Sample records for bubble rise characteristics
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Rise characteristics of gas bubbles in a 2D rectangular column: VOF simulations vs experiments
DOE Office of Scientific and Technical Information (OSTI.GOV)
Krishna, R.; Baten, J.M. van
About five centuries ago, Leonardo da Vinci described the sinuous motion of gas bubbles rising in water. The authors have attempted to simulate the rise trajectories of bubbles of 4, 5, 7, 8, 9, 12, and 20 mm in diameter rising in a 2D rectangular column filled with water. The simulations were carried out using the volume-of-fluid (VOF) technique developed by Hirt and Nichols (J. Computational Physics, 39, 201--225 (1981)). To solve the Navier-Stokes equations of motion the authors used a commercial solver, CFX 4.1c of AEA Technology, UK. They developed their own bubble-tracking algorithm to capture sinuous bubble motions.more » The 4 and 5 mm bubbles show large lateral motions observed by Da Vinci. The 7, 8 and 9 mm bubble behave like jellyfish. The 12 mm bubble flaps its wings like a bird. The extent of lateral motion of the bubbles decreases with increasing bubble size. Bubbles larger than 20 mm in size assume a spherical cap form and simulations of the rise characteristics match experiments exactly. VOF simulations are powerful tools for a priori determination of the morphology and rise characteristics of bubbles rising in a liquid. Bubble-bubble interactions are also properly modeled by the VOF technique.« less
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Bubble behavior characteristics based on virtual binocular stereo vision
NASA Astrophysics Data System (ADS)
Xue, Ting; Xu, Ling-shuang; Zhang, Shang-zhen
2018-01-01
The three-dimensional (3D) behavior characteristics of bubble rising in gas-liquid two-phase flow are of great importance to study bubbly flow mechanism and guide engineering practice. Based on the dual-perspective imaging of virtual binocular stereo vision, the 3D behavior characteristics of bubbles in gas-liquid two-phase flow are studied in detail, which effectively increases the projection information of bubbles to acquire more accurate behavior features. In this paper, the variations of bubble equivalent diameter, volume, velocity and trajectory in the rising process are estimated, and the factors affecting bubble behavior characteristics are analyzed. It is shown that the method is real-time and valid, the equivalent diameter of the rising bubble in the stagnant water is periodically changed, and the crests and troughs in the equivalent diameter curve appear alternately. The bubble behavior characteristics as well as the spiral amplitude are affected by the orifice diameter and the gas volume flow.
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Exploring the mechanisms of rising bubbles in marine biofouling prevention
NASA Astrophysics Data System (ADS)
Menesses, Mark; Belden, Jesse; Dickenson, Natasha; Bird, James
2015-11-01
Fluid motion, such as flow past a ship, is known to inhibit the growth of marine biofouling. Bubbles rising along a submerged structure also exhibit this behavior, which is typically attributed to buoyancy induced flow. However, the bubble interface may also have a direct influence on inhibiting growth that is independent of the surrounding flow. Here we aim to decouple these two mechanisms through a combination of field and laboratory experiments. In this study, a wall jet and a stream of bubbles are used to create two flows near a submerged solid surface where biofouling occurs. The flow structure characteristics were recorded using PIV. This experimental analysis allows for us to compare the efficacy of each flow relative to its flow parameters. Exploration of the mechanisms at play in the prevention of biofouling by use of rising bubbles provides a foundation to predict and optimize this antifouling technique under various conditions.
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From Rising Bubble to RNA/DNA and Bacteria
NASA Astrophysics Data System (ADS)
Marks, Roman; Cieszyńska, Agata; Wereszka, Marzena; Borkowski, Wojciech
2017-04-01
In this study we have focused on the movement of rising bubbles in a salty water body. Experiments reviled that free buoyancy movement of bubbles forces displacement of ions, located on the outer side of the bubble wall curvatures. During the short moment of bubble passage, all ions in the vicinity of rising bubble, are separated into anions that are gathered on the bubble upper half sphere and cations that slip along the bottom concave half-sphere of a bubble and develop a sub-bubble vortex. The principle of ions separation bases on the differences in displacement resistance. In this way, relatively heavier and larger, thus more resistant to displacement anions are gathered on the rising bubble upper half sphere, while smaller and lighter cations are assembled on the bottom half sphere and within the sub-bubble vortex. The acceleration of motion generates antiparallel rotary of bi-ionic domains, what implies that anions rotate in clockwise (CW) and cationic in counter-clockwise (CCW) direction. Then, both rotational systems may undergo splicing and extreme condensing by bi-pirouette narrowing of rotary. It is suggested that such double helix motion of bi-ionic domains creates RNA/DNA molecules. Finally, when the bubble reaches the water surface it burst and the preprocessed RNA/DNA matter is ejected into the droplets. Since that stage, droplet is suspended in positively charged troposphere, thus the cationic domain is located in the droplet center, whilst negative ions are attracted to configure the outer areola. According to above, the present study implies that the rising bubbles in salty waters may incept synergistic processing of matter resulting in its rotational/spherical organization that led to assembly of RNA/DNA molecules and bacteria cells.
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Rise of Air Bubbles in Aircraft Lubricating Oils
NASA Technical Reports Server (NTRS)
Robinson, J. V.
1950-01-01
Lubricating and antifoaming additives in aircraft lubricating oils may impede the escape of small bubbles from the oil by forming shells of liquid with a quasi-solid or gel structure around the bubbles. The rates of rise of small air bubbles, up to 2 millimeters in diameter, were measured at room temperature in an undoped oil, in the same oil containing foam inhibitors, and in an oil containing lubricating additives. The apparent diameter of the air bubbles was measured visually through an ocular micrometer on a traveling telescope. The bubbles in the undoped oil obeyed Stokes' Law, the rate of rise being proportional to the square of the apparent diameter and inversely proportional to the viscosity of the oil. The bubbles in the oils containing lubricating additives or foam inhibitors rose more slowly than the rate predicted by Stokes 1 Law from the apparent diameter, and the rate of rise decreased as the length of path the bubbles traveled increased. A method is derived to calculate the thickness of the liquid shell which would have to move with the bubbles in the doped oils to account for the abnoi'I!l8.lly slow velocity. The maximum thickness of this shell, calculated from the velocities observed, was equal to the bubble radius.
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NASA Astrophysics Data System (ADS)
Greinert, Jens; Artemov, Yuriy; Egorov, Viktor; De Batist, Marc; McGinnis, Daniel
2006-04-01
A mud volcano area in the deep waters (> 2000 m) of the Black Sea was studied by hydroacoustic measurements during several cruises between January 2002 and June 2004. Gas bubbles in the water column give strong backscatter signals and thus can be detected even in great water depths by echosounders as the 38 kHz EK500 scientific split-beam system that was used during the surveys. Because of their shape in echograms and to differentiate against geochemical plumes and real upwelling bubble-water plumes, we call these hydroacoustic manifestations of bubbles in the water column 'flares'. Digital recording and processing of the data allows a 3D visualization and data comparison over the entire observation period, without artefacts caused by changing system settings. During our surveys, we discovered bubble release from three separate mud volcanoes, Dvurechenskiy (DMV), Vodianitskiy (VMV) and the Nameless Seep Site (NSS), in about 2080 m water depth simultaneously. Bubble release was observed between 9 June 2003 and 5 June 2004. The most frequently surveyed, DMV, was found to be inactive during very intensive studies in January 2002. The first activity was observed on 27 June 2002, which finally ceased between 5 and 15 June 2004 after a period of continuously decreasing activity. This observed 2-yr bubble-release period at a mud volcano may give an indication for the duration of active periods. The absence of short-term variations (within days or hours) may indicate that the bubble release from the observed mud volcanoes does not undergo rapid changes. The recorded echograms show that bubbles rise about 1300 m high through the water column, to a final water depth of about 770 m, which is ˜75 m below the phase boundary of pure methane hydrate in the Black Sea. With a release depth from 2068 m and a detected rise height of 1300 m, the flare at VMV is among the deepest and highest reported so far, and gives evidence of highly extended bubble life times (up to 108 min) in
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A Study of Heat Transfer and Flow Characteristics of Rising Taylor Bubbles
NASA Technical Reports Server (NTRS)
Scammell, Alexander David
2016-01-01
Practical application of flow boiling to ground- and space-based thermal management systems hinges on the ability to predict the systems heat removal capabilities under expected operating conditions. Research in this field has shown that the heat transfer coefficient within two-phase heat exchangers can be largely dependent on the experienced flow regime. This finding has inspired an effort to develop mechanistic heat transfer models for each flow pattern which are likely to outperform traditional empirical correlations. As a contribution to the effort, this work aimed to identify the heat transfer mechanisms for the slug flow regime through analysis of individual Taylor bubbles.An experimental apparatus was developed to inject single vapor Taylor bubbles into co-currently flowing liquid HFE 7100. The heat transfer was measured as the bubble rose through a 6 mm inner diameter heated tube using an infrared thermography technique. High-speed flow visualization was obtained and the bubble film thickness measured in an adiabatic section. Experiments were conducted at various liquid mass fluxes (43-200 kgm2s) and gravity levels (0.01g-1.8g) to characterize the effect of bubble drift velocityon the heat transfer mechanisms. Variable gravity testing was conducted during a NASA parabolic flight campaign.Results from the experiments showed that the drift velocity strongly affects the hydrodynamics and heat transfer of single elongated bubbles. At low gravity levels, bubbles exhibited shapes characteristic of capillary flows and the heat transfer enhancement due to the bubble was dominated by conduction through the thin film. At moderate to high gravity, traditional Taylor bubbles provided small values of enhancement within the film, but large peaks in the wake heat transfer occurred due to turbulent vortices induced by the film plunging into the trailing liquid slug. Characteristics of the wake heat transfer profiles were analyzed and related to the predicted velocity field
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Study on drag coefficient of rising bubble in still water
NASA Astrophysics Data System (ADS)
Shi, M. Y.; Qi, Mei; Yi, C. G.; Liu, D. Y.; Zhang, K. X.
2017-09-01
Research on the behavior of a rising bubble in still water is on the basis of Newton's theory of classical mechanics. Develop a calculation analysis and an experimental process of bubble rising behavior in order to search for an appropriate way of valuing drag coefficient, which is the key element toward this issue. Analyze the adaptability of the drag coefficient; compare the theoretical model to the real experimental model of rising bubble behavior. The result turns out that the change rate of radius could be ignored according to the analysis; the acceleration phase is transient; final velocity and the diameter of bubble do relate to the drag coefficient, but have no obvious relation with the depth of water. After series of inference analysis of the bubble behavior and experimental demonstration, a new drag coefficient and computing method is proposed.
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Experimental study on wake structure of single rising clean bubble
NASA Astrophysics Data System (ADS)
Sato, Ayaka; Takedomi, Yuta; Shirota, Minori; Sanada, Toshiyuki; Watanabe, Masao
2007-11-01
Wake structure of clean bubble rising in quiescent silicone oil solution of photochromic dye is experimentally studied. A single bubble is generated, immediately after UV sheet light illuminates the part of the liquid just above the bubble generation nozzle in order to activate photochromic dye. Once the bubble passes across the colored part of the liquid, the bubble is accompanied by some portion of activated dye tracers; hence the flow structure in the rear of the single rising bubble is visualized. We capture stereo images of both wake structure and bubble motion. We study how wake structure changes with the increase in bubble size. We observe the stable axisymmetric wake structure, which is called `standing eddy' when bubble size is relatively small, and then wake structure becomes unstable and starts to oscillate with the increase in bubble size. With further increase in bubble size, a pair of streamwise vortices, which is called `double thread', is observed. We discuss in detail this transition from the steady wake to unsteady wake structure, especially double thread wake development and hairpin vortices shedding, in relation to the transition from rectilinear to spiral or zigzag bubble motions.
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Numerical simulation of superheated vapor bubble rising in stagnant liquid
NASA Astrophysics Data System (ADS)
Samkhaniani, N.; Ansari, M. R.
2017-09-01
In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.
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Liquid jet pumped by rising gas bubbles
NASA Technical Reports Server (NTRS)
Hussain, N. A.; Siegel, R.
1975-01-01
A two-phase mathematical model is proposed for calculating the induced turbulent vertical liquid flow. Bubbles provide a large buoyancy force and the associated drag on the liquid moves the liquid upward. The liquid pumped upward consists of the bubble wakes and the liquid brought into the jet region by turbulent entrainment. The expansion of the gas bubbles as they rise through the liquid is taken into account. The continuity and momentum equations are solved numerically for an axisymmetric air jet submerged in water. Water pumping rates are obtained as a function of air flow rate and depth of submergence. Comparisons are made with limited experimental information in the literature.
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NASA Astrophysics Data System (ADS)
Wang, Ye; Cai, Jiejin; Li, Qiong; Yin, Huaqiang; Yang, Xingtuan
2018-06-01
Gas-liquid two phase flow exists in several industrial processes and light-water reactors (LWRs). A diffuse interface based finite element method with two different mesh generation methods namely, the Adaptive Mesh Refinement (AMR) and the Arbitrary Lagrange Euler (ALE) methods is used to model the shape and velocity changes in a rising bubble. Moreover, the calculating speed and mesh generation strategies of AMR and ALE are contrasted. The simulation results agree with the Bhagat's experiments, indicating that both mesh generation methods can simulate the characteristics of bubble accurately. We concluded that: the small bubble rises as elliptical with oscillation, whereas a larger bubble (11 mm > d > 7 mm) rises with a morphology between the elliptical and cap type with a larger oscillation. When the bubble is large (d > 11 mm), it rises up as a cap type, and the amplitude becomes smaller. Moreover, it takes longer to achieve the stable shape from the ellipsoid to the spherical cap type with the increase of the bubble diameter. The results also show that for smaller diameter case, the ALE method uses fewer grids and has a faster calculation speed, but the AMR method can solve the case of a large geometry deformation efficiently.
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Rising dynamics of a bubble confined in vertical cells with rectangular cross-sections
NASA Astrophysics Data System (ADS)
Murano, Mayuko; Okumura, Ko
2017-11-01
Recently, the drag friction acting on a fluid drop in confined space has been actively studied. Here, we investigate the rising velocity of a bubble in a vertical cell with a rectangular cross-section, both theoretically and experimentally, in which understanding of the drag force acting on the rising bubble is crucial. Although the drag force in such confined space could involve several regimes, we study a special case in which the bubble is long and the aspect-ratio of the rectangular cross-section of the cell is high. As a result, we found new scaling law for the rising velocity and the drag force, and confirmed the laws experimentally. Crossover to the rising dynamics in a Hele-Shaw cell will be also discussed.
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Pore Size Control in Aluminium Foam by Standardizing Bubble Rise Velocity and Melt Viscosity
NASA Astrophysics Data System (ADS)
Avinash, G.; Harika, V.; Sandeepika, Ch; Gupta, N.
2018-03-01
In recent years, aluminium foams have found use in a wide range of applications. The properties of these foams, as good structural strength with light weight have made them as a promising structural material for aerospace industry. Foaming techniques (direct and indirect) are used to produce these foams. Direct foaming involves blowing of gas to create gas bubbles in the melt whereas indirect foaming technique uses blowing agents as metallic hydrides, which create hydrogen bubbles. Porosity and its distribution in foams directly affect its properties. This demands for more theoretical studies, to control such cellular structure and hence properties. In present work, we have studied the effect of gas bubble rise velocity and melt viscosity, on pore size and its distribution in aluminium foam. A 15 PPI aluminium foam, prepared using indirect foaming technique having porosity ~86 % was used for study. In order to obtain metal foam, the bubble must not escape from the melt and should get entrapped during solidification. Our calculations suggest that bubble rise velocity and melt viscosity are responsible for vertical displacement of bubble in the melt. It is observed that melt viscosity opposes bubble rise velocity and help the bubbles to stay in the melt, resulting in porous structure.
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NASA Astrophysics Data System (ADS)
Cano-Lozano, José Carlos; Martínez-Bazán, Carlos; Magnaudet, Jacques; Tchoufag, Joël
2016-09-01
We report on a series of results provided by three-dimensional numerical simulations of nearly spheroidal bubbles freely rising and deforming in a still liquid in the regime close to the transition to path instability. These results improve upon those of recent computational studies [Cano-Lozano et al., Int. J. Multiphase Flow 51, 11 (2013), 10.1016/j.ijmultiphaseflow.2012.11.005; Phys. Fluids 28, 014102 (2016), 10.1063/1.4939703] in which the neutral curve associated with this transition was obtained by considering realistic but frozen bubble shapes. Depending on the dimensionless parameters that characterize the system, various paths geometries are observed by letting an initially spherical bubble starting from rest rise under the effect of buoyancy and adjust its shape to the surrounding flow. These include the well-documented rectilinear axisymmetric, planar zigzagging, and spiraling (or helical) regimes. A flattened spiraling regime that most often eventually turns into either a planar zigzagging or a helical regime is also frequently observed. Finally, a chaotic regime in which the bubble experiences small horizontal displacements (typically one order of magnitude smaller than in the other regimes) is found to take place in a region of the parameter space where no standing eddy exists at the back of the bubble. The discovery of this regime provides evidence that path instability does not always result from a wake instability as previously believed. In each regime, we examine the characteristics of the path, bubble shape, and vortical structure in the wake, as well as their couplings. In particular, we observe that, depending on the fluctuations of the rise velocity, two different vortex shedding modes exist in the zigzagging regime, confirming earlier findings with falling spheres. The simulations also reveal that significant bubble deformations may take place along zigzagging or spiraling paths and that, under certain circumstances, they dramatically alter
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An analytical approach to the rise velocity of periodic bubble trains in non-Newtonian fluids.
Frank, X; Li, H Z; Funfschilling, D
2005-01-01
The present study aims at providing insight into the acceleration mechanism of a bubble chain rising in shear-thinning viscoelastic fluids. The experimental investigation by the Particle Image Velocimetry (PIV), birefringence visualisation and rheological simulation shows that two aspects are central to bubble interactions in such media: the stress creation by the passage of bubbles, and their relaxation due to the fluid's memory forming an evanescent corridor of reduced viscosity. Interactions between bubbles were taken into account mainly through a linear superposition of the stress evolution behind each bubble. An analytical approach together with the rheological consideration was developed to compute the rise velocity of a bubble chain in function of the injection period and bubble volume. The model predictions compare satisfactorily with the experimental investigation.
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Dynamics of the liquid film around elongated bubbles rising in vertical capillaries
NASA Astrophysics Data System (ADS)
Magnini, Mirco; Khodaparast, Sepideh; Matar, Omar K.; Stone, Howard A.; Thome, John R.
2017-11-01
We performed a theoretical, numerical and experimental study on elongated bubbles rising in vertical tubes in co-current liquid flows. The flow conditions were characterized by capillary, Reynolds and Bond numbers within the range of Ca = 0.005 - 0.1 , Re = 1 - 2000 and Bo = 0 - 20 . Direct numerical simulations of the two-phase flows are run with a self-improved version of OpenFOAM, implementing a coupled Level Set and Volume of Fluid method. A theoretical model based on an extension of the traditional Bretherton theory, accounting for inertia and the gravity force, is developed to obtain predictions of the profiles of the front and rear menisci of the bubble, liquid film thickness and bubble velocity. Different from the traditional theory for bubbles rising in a stagnant liquid, the gravity force impacts the flow already when Bo < 4 . Gravity effects speed up the bubble compared to the Bo = 0 case, making the liquid film thicker and reducing the amplitude of the undulation on the surface of the bubble near its tail. Gravity effects are more apparent in the visco-capillary regime, i.e. when the Reynolds number is below 1.
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NASA Technical Reports Server (NTRS)
Onorato, P. I. K.; Weinberg, M. C.; Uhlmann, D. R.
1981-01-01
Finite difference solutions of the mass transport equations governing the dissolution (growth) of a rising gas bubble, containing a single gas, in a glassmelt were obtained. These solutions were compared with those obtained from an approximate procedure for a range of the controlling parameters. Applications were made to describe various aspects of O2 and CO2 gas-bubble behavior in a soda-lime-silicate melt.
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Rise of an argon bubble in liquid steel in the presence of a transverse magnetic field
NASA Astrophysics Data System (ADS)
Jin, K.; Kumar, P.; Vanka, S. P.; Thomas, B. G.
2016-09-01
The rise of gaseous bubbles in viscous liquids is a fundamental problem in fluid physics, and it is also a common phenomenon in many industrial applications such as materials processing, food processing, and fusion reactor cooling. In this work, the motion of a single argon gas bubble rising in quiescent liquid steel under an external magnetic field is studied numerically using a Volume-of-Fluid method. To mitigate spurious velocities normally generated during numerical simulation of multiphase flows with large density differences, an improved algorithm for surface tension modeling, originally proposed by Wang and Tong ["Deformation and oscillations of a single gas bubble rising in a narrow vertical tube," Int. J. Therm. Sci. 47, 221-228 (2008)] is implemented, validated and used in the present computations. The governing equations are integrated by a second-order space and time accurate numerical scheme, and implemented on multiple Graphics Processing Units with high parallel efficiency. The motion and terminal velocities of the rising bubble under different magnetic fields are compared and a reduction in rise velocity is seen in cases with the magnetic field applied. The shape deformation and the path of the bubble are discussed. An elongation of the bubble along the field direction is seen, and the physics behind these phenomena is discussed. The wake structures behind the bubble are visualized and effects of the magnetic field on the wake structures are presented. A modified drag coefficient is obtained to include the additional resistance force caused by adding a transverse magnetic field.
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Rise of an argon bubble in liquid steel in the presence of a transverse magnetic field
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jin, K.; Kumar, P.; Vanka, S. P., E-mail: spvanka@illinois.edu
2016-09-15
The rise of gaseous bubbles in viscous liquids is a fundamental problem in fluid physics, and it is also a common phenomenon in many industrial applications such as materials processing, food processing, and fusion reactor cooling. In this work, the motion of a single argon gas bubble rising in quiescent liquid steel under an external magnetic field is studied numerically using a Volume-of-Fluid method. To mitigate spurious velocities normally generated during numerical simulation of multiphase flows with large density differences, an improved algorithm for surface tension modeling, originally proposed by Wang and Tong [“Deformation and oscillations of a single gasmore » bubble rising in a narrow vertical tube,” Int. J. Therm. Sci. 47, 221–228 (2008)] is implemented, validated and used in the present computations. The governing equations are integrated by a second-order space and time accurate numerical scheme, and implemented on multiple Graphics Processing Units with high parallel efficiency. The motion and terminal velocities of the rising bubble under different magnetic fields are compared and a reduction in rise velocity is seen in cases with the magnetic field applied. The shape deformation and the path of the bubble are discussed. An elongation of the bubble along the field direction is seen, and the physics behind these phenomena is discussed. The wake structures behind the bubble are visualized and effects of the magnetic field on the wake structures are presented. A modified drag coefficient is obtained to include the additional resistance force caused by adding a transverse magnetic field.« less
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Numerical study of wall effects on buoyant gas-bubble rise in a liquid-filled finite cylinder
Mukundakrishnan, Karthik; Quan, Shaoping; Eckmann, David M.; Ayyaswamy, Portonovo S.
2009-01-01
The wall effects on the axisymmetric rise and deformation of an initially spherical gas bubble released from rest in a liquid-filled, finite circular cylinder are numerically investigated. The bulk and gas phases are considered incompressible and immiscible. The bubble motion and deformation are characterized by the Morton number (Mo), Eötvös number (Eo), Reynolds number (Re), Weber number (We), density ratio, viscosity ratio, the ratios of the cylinder height and the cylinder radius to the diameter of the initially spherical bubble (H* = H/d0, R* = R/d0). Bubble rise in liquids described by Eo and Mo combinations ranging from (1,0.01) to (277.5,0.092), as appropriate to various terminal state Reynolds numbers (ReT) and shapes have been studied. The range of terminal state Reynolds numbers includes 0.02 < ReT < 70. Bubble shapes at terminal states vary from spherical to intermediate spherical-cap–skirted. The numerical procedure employs a front tracking finite difference method coupled with a level contour reconstruction of the front. This procedure ensures a smooth distribution of the front points and conserves the bubble volume. For the wide range of Eo and Mo examined, bubble motion in cylinders of height H* = 8 and R* ≥ 3, is noted to correspond to the rise in an infinite medium, both in terms of Reynolds number and shape at terminal state. In a thin cylindrical vessel (small R*), the motion of the bubble is retarded due to increased total drag and the bubble achieves terminal conditions within a short distance from release. The wake effects on bubble rise are reduced, and elongated bubbles may occur at appropriate conditions. For a fixed volume of the bubble, increasing the cylinder radius may result in the formation of well-defined rear recirculatory wakes that are associated with lateral bulging and skirt formation. The paper includes figures of bubble shape regimes for various values of R*, Eo, Mo, and ReT. Our predictions agree with existing results
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Effervescence in champagne and sparkling wines: From grape harvest to bubble rise
NASA Astrophysics Data System (ADS)
Liger-Belair, Gérard
2017-01-01
Bubbles in a glass of champagne may seem like the acme of frivolity to most of people, but in fact they may rather be considered as a fantastic playground for any fluid physicist. Under standard tasting conditions, about a million bubbles will nucleate and rise if you resist drinking from your flute. The so-called effervescence process, which enlivens champagne and sparkling wines tasting, is the result of the complex interplay between carbon dioxide (CO2) dissolved in the liquid phase, tiny air pockets trapped within microscopic particles during the pouring process, and some both glass and liquid properties. In this tutorial review, the journey of yeast-fermented CO2 is reviewed (from its progressive dissolution in the liquid phase during the fermentation process, to its progressive release in the headspace above glasses). The most recent advances about the physicochemical processes behind the nucleation, and rise of gaseous CO2 bubbles, under standard tasting conditions, have been gathered hereafter. Let's hope that your enjoyment of champagne will be enhanced after reading this tutorial review dedicated to the unsuspected physics hidden right under your nose each time you enjoy a glass of bubbly.
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Morphological Studies of Rising Equatorial Spread F Bubbles
1977-11-01
depletions. In the present paper , we wish to discuss equatorial Spread F bubble shapes and vertical rise rates within the context of the collisional...simulation results are needed to ascertain which model fits best. All of the models described in this paper , based on collisional Rayleigh-Taylor type...Analysis of Barium Clouds - Semi-Annual Technical Report, RADC-TR-72-103, Vol. I, Avco Everett Reserach Laboratory, Everett, Mass., January 1972
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The hydrodynamics of bubble rise and impact with solid surfaces.
Manica, Rogerio; Klaseboer, Evert; Chan, Derek Y C
2016-09-01
A bubble smaller than 1mm in radius rises along a straight path in water and attains a constant speed due to the balance between buoyancy and drag force. Depending on the purity of the system, within the two extreme limits of tangentially immobile or mobile boundary conditions at the air-water interface considerably different terminal speeds are possible. When such a bubble impacts on a horizontal solid surface and bounces, interesting physics can be observed. We study this physical phenomenon in terms of forces, which can be of colloidal, inertial, elastic, surface tension and viscous origins. Recent advances in high-speed photography allow for the observation of phenomena on the millisecond scale. Simultaneous use of such cameras to visualize both rise/deformation and the dynamics of the thin film drainage through interferometry are now possible. These experiments confirm that the drainage process obeys lubrication theory for the spectrum of micrometre to millimetre-sized bubbles that are covered in this review. We aim to bridge the colloidal perspective at low Reynolds numbers where surface forces are important to high Reynolds number fluid dynamics where the effect of the surrounding flow becomes important. A model that combines a force balance with lubrication theory allows for the quantitative comparison with experimental data under different conditions without any fitting parameter. Copyright © 2016 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Shafiei Dizaji, A.; Mohammadpourfard, M.; Aminfar, H.
2018-03-01
Multiphase flow is one of the most complicated problems, considering the multiplicity of the related parameters, especially the external factors influences. Thus, despite the recent developments more investigations are still required. The effect of a uniform magnetic field on the hydrodynamics behavior of a two-phase flow with different magnetic permeability is presented in this article. A single water vapor bubble which is rising inside a channel filled with ferrofluid has been simulated numerically. To capture the phases interface, the Volume of Fluid (VOF) model, and to solve the governing equations, the finite volume method has been employed. Contrary to the prior anticipations, while the consisting fluids of the flow are dielectric, uniform magnetic field causes a force acting normal to the interface toward to the inside of the bubble. With respect to the applied magnetic field direction, the bubble deformation due to the magnetic force increases the bubble rising velocity. Moreover, the higher values of applied magnetic field strength and magnetic permeability ratio resulted in the further increase of the bubble rising velocity. Also it is indicated that the flow mixing and the heat transfer rate is increased by a bubble injection and applying a magnetic field. The obtained results have been concluded that the presented phenomenon with applying a magnetic field can be used to control the related characteristics of the multiphase flows. Compared to the previous studies, implementing the applicable cases using the common and actual materials and a significant reduction of the CPU time are the most remarkable advantages of the current study.
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Numerical simulation of a bubble rising in an environment consisting of Xanthan gum
NASA Astrophysics Data System (ADS)
Aguirre, Víctor A.; Castillo, Byron A.; Narvaez, Christian P.
2017-09-01
An improved numerical algorithm for front tracking method is developed to simulate a bubble rising in viscous liquid. In the new numerical algorithm, volume correction is introduced to conserve the bubble volume while tracking the bubble's rising and deforming. Volume flux conservation is adopted to solve the Navier-Stokes equation for fluid flow using finite volume method. Non-Newtonian fluids are widely used in industry such as feed and energy industries. In this research we used Xanthan gum which is a microbiological polysaccharide. In order to obtain the properties of the Xanthan gum, such as viscosity, storage and loss modulus, shear rate, etc., it was necessary to do an amplitude sweep and steady flow test in a rheometer with a concentric cylinder as geometry. Based on the data given and using a numerical regression, the coefficients required by Giesekus model are obtained. With these coefficients, it is possible to simulate the comportment of the fluid by the use of the developed algorithm. Once the data given by OpenFOAM is acquired, it is compared with the experimental data.
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Prediction of the rate of the rise of an air bubble in nanofluids in a vertical tube.
Cho, Heon Ki; Nikolov, Alex D; Wasan, Darsh T
2018-04-19
Our recent experiments have demonstrated that when a bubble rises through a nanofluid (a liquid containing dispersed nanoparticles) in a vertical tube, a nanofluidic film with several particle layers is formed between the gas bubble and the glass tube wall, which significantly changes the bubble velocity due to the nanoparticle layering phenomenon in the film. We calculated the structural nanofilm viscosity as a function of the number of particle layers confined in it and found that the film viscosity increases rather steeply when the film contains only one or two particle layers. The nanofilm viscosity was found to be several times higher than the bulk viscosity of the fluid. Consequently, the Bretherton equation cannot accurately predict the rate of the rise of a slow-moving long bubble in a vertical tube in a nanofluid because it is valid only for very thick films and uses the bulk viscosity of the fluid. However, in this brief note, we demonstrate that the Bretherton equation can indeed be used for predicting the rate of the rise of a long single bubble through a vertical tube filled with a nanofluid by simply replacing the bulk viscosity with the proper structural nanofilm viscosity of the fluid. Copyright © 2018. Published by Elsevier Inc.
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NASA Astrophysics Data System (ADS)
Tulasi Ram, S.; Ajith, K. K.; Yokoyama, T.; Yamamoto, M.; Niranjan, K.
2017-06-01
The vertical rise velocity (Vr) and maximum altitude (Hm) of equatorial plasma bubbles (EPBs) were estimated using the two-dimensional fan sector maps of 47 MHz Equatorial Atmosphere Radar (EAR), Kototabang, during May 2010 to April 2013. A total of 86 EPBs were observed out of which 68 were postsunset EPBs and remaining 18 EPBs were observed around midnight hours. The vertical rise velocities of the EPBs observed around the midnight hours are significantly smaller ( 26-128 m/s) compared to those observed in postsunset hours ( 45-265 m/s). Further, the vertical growth of the EPBs around midnight hours ceases at relatively lower altitudes, whereas the majority of EPBs at postsunset hours found to have grown beyond the maximum detectable altitude of the EAR. The three-dimensional numerical high-resolution bubble (HIRB) model with varying background conditions are employed to investigate the possible factors that control the vertical rise velocity and maximum attainable altitudes of EPBs. The estimated rise velocities from EAR observations at both postsunset and midnight hours are, in general, consistent with the nonlinear evolution of EPBs from the HIRB model. The smaller vertical rise velocities (Vr) and lower maximum altitudes (Hm) of EPBs during midnight hours are discussed in terms of weak polarization electric fields within the bubble due to weaker background electric fields and reduced background ion density levels.
Plain Language SummaryEquatorial plasma <span class="hlt">bubbles</span> are plasma density irregularities in the ionosphere. The radio waves passing through these irregular density structures undergo severe degradation/scintillation that could cause severe disruption of satellite-based communication and augmentation systems such as GPS navigation. These <span class="hlt">bubbles</span> develop at geomagnetic equator, grow vertically, and elongate along the field lines to latitudes away from the equator. The knowledge on <span class="hlt">bubble</span> <span class="hlt">rise</span> velocities and their</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFDH11002T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFDH11002T"><span>The effect of surfactants on path instability of a <span class="hlt">rising</span> <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tagawa, Yoshiyuki; Takagi, Shu; Matsumoto, Yoichiro</p> <p>2013-11-01</p> <p>We experimentally investigate the surfactant effect on path instability of an air <span class="hlt">bubble</span> <span class="hlt">rising</span> in quiescent water. An addition of surfactant varies the gas-water boundary condition from zero shear stress to non-zero shear stress. We report three main findings: firstly, while the drag force acting on the <span class="hlt">bubble</span> increases with the surfactant concentration as expected, the lift force shows a non-monotonic behavior; secondly, the transient trajectory starting from helical to zigzag is observed, which has never been reported in the case of purified water; lastly, a <span class="hlt">bubble</span> with the intermediate slip conditions between free-slip and no-slip show a helical motion for a broad range of the Reynolds number. Aforementioned results are rationalized by considering the adsorption-desorption kinetics of the surfactants on gas-water interface and the wake dynamics. Y.T. thanks for financial support from Grant-in-Aid for JSPS Fellows (20-10701). We also thank for Grant-in-Aid for Scientific Research (B) (21360079).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850035784&hterms=lime&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlime','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850035784&hterms=lime&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlime"><span>Velocity of a freely <span class="hlt">rising</span> gas <span class="hlt">bubble</span> in a soda-lime silicate glass melt</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hornyak, E. J.; Weinberg, M. C.</p> <p>1984-01-01</p> <p>A comparison is conducted between measured velocities for the buoyant <span class="hlt">rise</span> of single <span class="hlt">bubbles</span> of varying size and composition, in a soda-lime silicate glass melt, with the steady state velocities predicted by the Stokes and Hadamard-Rybczynski formulas. In all cases, the data are noted to fit the Hadamard-Rybczynski expression for steady state <span class="hlt">rise</span> speed considerably better than the Stokes formula.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19288095','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19288095"><span>The "<span class="hlt">rising</span> <span class="hlt">bubble</span>" sign: a new aid in the diagnosis of unicameral bone cysts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jordanov, Martin I</p> <p>2009-06-01</p> <p>The observation of a <span class="hlt">bubble</span> of gas at the most non-dependent margin of a lytic bone lesion which has sustained a pathologic fracture implies that the lesion is hollow and can assist the radiologist in making the diagnosis of a unicameral bone cyst. The imaging studies of two patients who sustained pathologic fractures through unicameral bone cysts and exhibited the "<span class="hlt">rising</span> <span class="hlt">bubble</span>" sign are shown. The sign's basis, proper utilization, and potential pitfalls are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhFl...24k2101O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhFl...24k2101O"><span>The buoyancy-driven motion of a single skirted <span class="hlt">bubble</span> or drop <span class="hlt">rising</span> through a viscous liquid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohta, Mitsuhiro; Sussman, Mark</p> <p>2012-11-01</p> <p>The buoyancy-driven motion of a single skirted <span class="hlt">bubble</span> or drop <span class="hlt">rising</span> through a viscous liquid is computationally explored by way of 3d-axisymmetric computations. The Navier-Stokes equations for incompressible two-fluid flow are solved numerically in which the coupled level-set and volume-of-fluid method is used to simulate the deforming <span class="hlt">bubble</span>/drop boundary and the interface jump conditions on the deforming boundary are enforced through a sharp interface numerical treatment. Dynamic, block structured adaptive grid refinement is employed in order to sufficiently resolve the thin skirts. Results on the sensitivity of the thickness of trailing <span class="hlt">bubble</span>/drop skirts to the density ratio and viscosity ratio are reported. It is shown that both the density ratio (not the density difference) and the viscosity ratio effect the skirt thickness. Previous theory for predicting skirt thickness can be refined as a result of our calculations. It is also discovered that the formation of thin skirts for <span class="hlt">bubbles</span> and drops have little effect on the <span class="hlt">rise</span> velocity. In other words, the measured Re number for cases without skirt formation have almost the same values for Re as cases with a thin skirt.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA12A..06Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA12A..06Y"><span>Vertical <span class="hlt">Rise</span> Velocity of Equatorial Plasma <span class="hlt">Bubbles</span> Estimated from Equatorial Atmosphere Radar Observations and High-Resolution <span class="hlt">Bubble</span> Model Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yokoyama, T.; Ajith, K. K.; Yamamoto, M.; Niranjan, K.</p> <p>2017-12-01</p> <p>Equatorial plasma <span class="hlt">bubble</span> (EPB) is a well-known phenomenon in the equatorial ionospheric F region. As it causes severe scintillation in the amplitude and phase of radio signals, it is important to understand and forecast the occurrence of EPBs from a space weather point of view. The development of EPBs is presently believed as an evolution of the generalized Rayleigh-Taylor instability. We have already developed a 3D high-resolution <span class="hlt">bubble</span> (HIRB) model with a grid spacing of as small as 1 km and presented nonlinear growth of EPBs which shows very turbulent internal structures such as bifurcation and pinching. As EPBs have field-aligned structures, the latitude range that is affected by EPBs depends on the apex altitude of EPBs over the dip equator. However, it was not easy to observe the apex altitude and vertical <span class="hlt">rise</span> velocity of EPBs. Equatorial Atmosphere Radar (EAR) in Indonesia is capable of steering radar beams quickly so that the growth phase of EPBs can be captured clearly. The vertical <span class="hlt">rise</span> velocities of the EPBs observed around the midnight hours are significantly smaller compared to those observed in postsunset hours. Further, the vertical growth of the EPBs around midnight hours ceases at relatively lower altitudes, whereas the majority of EPBs at postsunset hours found to have grown beyond the maximum detectable altitude of the EAR. The HIRB model with varying background conditions are employed to investigate the possible factors that control the vertical <span class="hlt">rise</span> velocity and maximum attainable altitudes of EPBs. The estimated <span class="hlt">rise</span> velocities from EAR observations at both postsunset and midnight hours are, in general, consistent with the nonlinear evolution of EPBs from the HIRB model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011TRACE..12...31I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011TRACE..12...31I"><span>Cold Heat Release <span class="hlt">Characteristics</span> of Solidified Oil Droplet-Water Solution Latent Heat Emulsion by Air <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Inaba, Hideo; Morita, Shin-Ichi</p> <p></p> <p>The present work investigates the cold heat-release <span class="hlt">characteristics</span> of the solidified oil droplets (tetradecane, C14H30, freezing point 278.9 K)/water solution emulsion as a latent heat-storage material having a low melting point. An air <span class="hlt">bubbles</span>-emulsion direct-contact heat exchange method is selected for the cold heat-results from the solidified oil droplet-emulsion layer. This type of direct-contact method results in the high thermal efficiency. The diameter of air <span class="hlt">bubbles</span> in the emulsion increases as compared with that in the pure water. The air <span class="hlt">bubbles</span> blown from a nozzle show a strong mixing behavior during <span class="hlt">rising</span> in the emulsion. The temperature effectiveness, the sensible heat release time and the latent heat release time have been measured as experimental parameters. The useful nondimensional emulsion level equations for these parameters have been derived in terms of the nondimensional emalsion level expressed the emulsion layer dimensions, Reynolds number for air flow, Stefan number and heat capacity ratio.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AIPC..676..370T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AIPC..676..370T"><span>Anti-<span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tufaile, Alberto; Sartorelli, José Carlos</p> <p>2003-08-01</p> <p>An anti-<span class="hlt">bubble</span> is a striking kind of <span class="hlt">bubble</span> in liquid that seemingly does not comply the buoyancy, and after few minutes it disappears suddenly inside the liquid. Different from a simple air <span class="hlt">bubble</span> that <span class="hlt">rises</span> directly to the liquid surface, an anti-<span class="hlt">bubble</span> wanders around in the fluid due to its slightly lesser density than the surrounding liquid. In spite of this odd behavior, an anti-<span class="hlt">bubble</span> can be understood as the opposite of a conventional soap <span class="hlt">bubble</span> in air, which is a shell of liquid surrounding air, and an anti-<span class="hlt">bubble</span> is a shell of air surrounding a drop of the liquid inside the liquid. Two-phase flow has been a subject of interest due to its relevance to process equipment for contacting gases and liquids applied in industry. A chain of <span class="hlt">bubbles</span> <span class="hlt">rising</span> in a liquid formed from a nozzle is a two-phase flow, and there are certain conditions in which spherical air shells, called anti-<span class="hlt">bubbles</span>, are produced. The purpose of this work is mainly to note the existence of anti-<span class="hlt">bubbling</span> regime as a sequel of a <span class="hlt">bubbling</span> system. We initially have presented the experimental apparatus. After this we have described the evolution of the <span class="hlt">bubbling</span> regimes, and emulated the effect of <span class="hlt">bubbling</span> coalescence with simple maps. Then is shown the inverted dripping as a consequence of the <span class="hlt">bubble</span> coalescence, and finally the conditions for anti-<span class="hlt">bubble</span> formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MAR.M1187S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MAR.M1187S"><span>Interfacial <span class="hlt">Bubble</span> Deformations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seymour, Brian; Shabane, Parvis; Cypull, Olivia; Cheng, Shengfeng; Feitosa, Klebert</p> <p></p> <p>Soap <span class="hlt">bubbles</span> floating at an air-water experience deformations as a result of surface tension and hydrostatic forces. In this experiment, we investigate the nature of such deformations by taking cross-sectional images of <span class="hlt">bubbles</span> of different volumes. The results show that as their volume increases, <span class="hlt">bubbles</span> transition from spherical to hemispherical shape. The deformation of the interface also changes with <span class="hlt">bubble</span> volume with the capillary <span class="hlt">rise</span> converging to the capillary length as volume increases. The profile of the top and bottom of the <span class="hlt">bubble</span> and the capillary <span class="hlt">rise</span> are completely determined by the volume and pressure differences. James Madison University Department of Physics and Astronomy, 4VA Consortium, Research Corporation for Advancement of Science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HMT...tmp...42D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HMT...tmp...42D"><span>Visualisation of gas-liquid mass transfer around a <span class="hlt">rising</span> <span class="hlt">bubble</span> in a quiescent liquid using an oxygen sensitive dye</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dietrich, Nicolas; Hebrard, Gilles</p> <p>2018-02-01</p> <p>An approach for visualizing and measuring the mass transfer around a single <span class="hlt">bubble</span> <span class="hlt">rising</span> in a quiescent liquid is reported. A colorimetric technique, developed by (Dietrich et al. Chem Eng Sci 100:172-182, 2013) using an oxygen sensitive redox dye was implemented. It was based on the reduction of the colorimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected because it offered various reduced forms with colours ranging from transparent (without oxygen) to pink (in presence of oxygen). These advantages made it possible to visualize the spatio-temporal oxygen mass transfer around <span class="hlt">rising</span> <span class="hlt">bubbles</span>. Images were recorded by a CCD camera and, after post-processing, the shape, size, and velocity of the <span class="hlt">bubbles</span> were measured and the colours around the <span class="hlt">bubbles</span> mapped. A calibration, linking the level of colour with the dissolved oxygen concentration, enabled colour maps to be converted into oxygen concentration fields. A rheoscopic fluid was used to visualize the wake of the <span class="hlt">bubbles</span>. A calculation method was also developed to determine the transferred oxygen fluxes around <span class="hlt">bubbles</span> of two sizes (d = 0.82 mm and d = 2.12 mm) and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with classical global measurements made by oxygen micro-sensors or from the classical models. This study thus constitutes a striking example of how this new colorimetric method could become a remarkable tool for exploring gas-liquid mass transfer in fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HMT....54.2163D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HMT....54.2163D"><span>Visualisation of gas-liquid mass transfer around a <span class="hlt">rising</span> <span class="hlt">bubble</span> in a quiescent liquid using an oxygen sensitive dye</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dietrich, Nicolas; Hebrard, Gilles</p> <p>2018-07-01</p> <p>An approach for visualizing and measuring the mass transfer around a single <span class="hlt">bubble</span> <span class="hlt">rising</span> in a quiescent liquid is reported. A colorimetric technique, developed by (Dietrich et al. Chem Eng Sci 100:172-182, 2013) using an oxygen sensitive redox dye was implemented. It was based on the reduction of the colorimetric indicator in presence of oxygen, this reduction being catalysed by sodium hydroxide and glucose. In this study, resazurin was selected because it offered various reduced forms with colours ranging from transparent (without oxygen) to pink (in presence of oxygen). These advantages made it possible to visualize the spatio-temporal oxygen mass transfer around <span class="hlt">rising</span> <span class="hlt">bubbles</span>. Images were recorded by a CCD camera and, after post-processing, the shape, size, and velocity of the <span class="hlt">bubbles</span> were measured and the colours around the <span class="hlt">bubbles</span> mapped. A calibration, linking the level of colour with the dissolved oxygen concentration, enabled colour maps to be converted into oxygen concentration fields. A rheoscopic fluid was used to visualize the wake of the <span class="hlt">bubbles</span>. A calculation method was also developed to determine the transferred oxygen fluxes around <span class="hlt">bubbles</span> of two sizes (d = 0.82 mm and d = 2.12 mm) and the associated liquid-side mass transfer coefficients. The results compared satisfactorily with classical global measurements made by oxygen micro-sensors or from the classical models. This study thus constitutes a striking example of how this new colorimetric method could become a remarkable tool for exploring gas-liquid mass transfer in fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.Q3002B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.Q3002B"><span>Air <span class="hlt">bubbles</span> induce a critical continuous stress to prevent marine biofouling accumulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belden, Jesse; Menesses, Mark; Dickenson, Natasha; Bird, James</p> <p>2017-11-01</p> <p>Significant shear stresses are needed to remove established hard fouling organisms from a ship hull. Given that there is a link between the amount of time that fouling accumulates and the stress required to remove it, it is not surprising that more frequent grooming requires less shear stress. One approach to mitigate marine biofouling is to continuously introduce a curtain of air <span class="hlt">bubbles</span> under a submerged surface; it is believed that this aeration exploits the small stresses induced by <span class="hlt">rising</span> <span class="hlt">bubbles</span> to continuously prevent accumulation. Although curtains of <span class="hlt">rising</span> <span class="hlt">bubbles</span> have successfully prevented biofouling accumulation, it is unclear if a single stream of <span class="hlt">bubbles</span> could maintain a clean surface. In this talk, we show that single <span class="hlt">bubble</span> stream aeration can prevent biofouling accumulation in regions for which the average wall stress exceeds approximately 0.01 Pa. This value is arrived at by comparing observations of biofouling growth and prevention from field studies with laboratory measurements that probe the associated flow fields. We also relate the spatial and temporal <span class="hlt">characteristics</span> of the flow to the size and frequency of the <span class="hlt">rising</span> <span class="hlt">bubbles</span>, which informs the basic operating conditions required for aeration to continuously prevent biofouling accumulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/7119902-transformer-overload-characteristics-bubble-evolution','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/7119902-transformer-overload-characteristics-bubble-evolution"><span>Transformer overload <span class="hlt">characteristics---Bubble</span> evolution</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Woods, E.E.; Wendel, R.C.; Dresser, R.D.</p> <p>1988-08-01</p> <p>Project RP1289-3 explores significant parameters affecting <span class="hlt">bubble</span> evolution from transformer oil under high temperature operating conditions to address the question: Does ''real life'' operation of a transformer cause harmful <span class="hlt">bubbling</span> conditions. Studies outlined in the project are designed to determine when <span class="hlt">bubbling</span> occurs in transformers and if <span class="hlt">bubbling</span> can be harmful during the normal operation of these transformers. Data obtained from these studies should provide a basis for utilities to perform risk assessments in relation to their loading practices. The program is designed to demonstrate those conditions under which <span class="hlt">bubbling</span> occurs in transformers by using controlled models and actual signalmore » phase transformers that were designed to give access to both high and low voltage windings for the purpose of viewing <span class="hlt">bubble</span> generation. Results and observations from tests on the full-size transformers, thermal models, and electrical models have led to the conclusion that <span class="hlt">bubbles</span> can occur under operating conditions. The electrical models show that dielectric strength can be reduced by as much as 40 percent due to the presence of <span class="hlt">bubbles</span>. Because of factory safety considerations, the transformers could not be tested at hot spot temperatures greater than 140/degree/C. Therefore, there is no information on the dielectric strength of the full-size transformers under <span class="hlt">bubbling</span> conditions. 4 refs., 28 figs., 45 tabs.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H33A1514H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H33A1514H"><span>Effects of Particle Size and <span class="hlt">Bubble</span> <span class="hlt">Characteristics</span> on Transport of Micro- and Nano-<span class="hlt">Bubbles</span> in Saturated Porous Media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamamoto, S.; Nihei, N.; Ueda, Y.; Moldrup, P.; Nishimura, T.</p> <p>2016-12-01</p> <p>The micro- and nano-<span class="hlt">bubbles</span> (MNBs) have considerable potentials for the remediation of soil contaminated by organic compounds when used in conjunction with bioremediation technology. Understanding a transport mechanism of MNBs in soils is essential to optimize remediation techniques using MNBs. In this study, column transport experiments using glass beads with different size fractions (average particles size: 0.1 mm and 0.4 mm) were conducted, where MNBs created by oxygen gas were injected to the column with different flow rates. Effects of particle size and <span class="hlt">bubble</span> <span class="hlt">characteristics</span> on MNB transport in porous media were investigated based on the column experiments. The results showed that attachments of MNBs were enhanced under lower flow rate. Under higher flow rate condition, there were not significant differences of MNBs transport in porous media with different particle size. A convection-dispersion model including <span class="hlt">bubble</span> attachment, detachment, and straining terms was applied to the obtained breakthrough curves for each experiment, showing good fitness against the measured data. Further investigations will be conducted to understand <span class="hlt">bubble</span> <span class="hlt">characteristics</span> including <span class="hlt">bubble</span> size and zeta potential on MNB transport in porous media. Relations between in model parameters in the transport model and physical and chemical properties in porous media and MNBs will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/4203505','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/4203505"><span>CONTINUOUSLY SENSITIVE <span class="hlt">BUBBLE</span> CHAMBER</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Good, R.H.</p> <p>1959-08-18</p> <p>A radiation detector of the <span class="hlt">bubble</span> chamber class is described which is continuously sensitive and which does not require the complex pressure cycling equipment <span class="hlt">characteristic</span> of prior forms of the chamber. The radiation sensitive element is a gas-saturated liquid and means are provided for establishing a thermal gradient across a region of the liquid. The gradient has a temperature range including both the saturation temperature of the liquid and more elevated temperatures. Thus a supersaturated zone is created in which ionizing radiations may give <span class="hlt">rise</span> to visible gas <span class="hlt">bubbles</span> indicative of the passage of the radiation through the liquid. Additional means are provided for replenishing the supply of gas-saturated liquid to maintaincontinuous sensitivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFD.E4004G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFD.E4004G"><span>On the Physics of Fizziness: How liquid properties control bursting <span class="hlt">bubble</span> aerosol production?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe; Seon, Thomas</p> <p>2014-11-01</p> <p>Either in a champagne glass or at the oceanic scales, the tiny capillary <span class="hlt">bubbles</span> <span class="hlt">rising</span> at the surface burst in ejecting myriads of droplets. Focusing on the ejected droplets produced by a single <span class="hlt">bubble</span>, we investigate experimentally how liquid properties and <span class="hlt">bubble</span> size affect their <span class="hlt">characteristics</span>: number, ejection velocities, sizes and ejection heights. These results allow us to finely tune the bursting <span class="hlt">bubble</span> aerosol production. In the context of champagne industry, aerosols play a major role by spreading wine aroma above the glass. We demonstrate that this champagne fizz can be enhanced by selecting the wine viscosity and the <span class="hlt">bubble</span> size, thanks to specially designed glass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=calculus+AND+8&pg=2&id=EJ914739','ERIC'); return false;" href="https://eric.ed.gov/?q=calculus+AND+8&pg=2&id=EJ914739"><span>In Search of the Big <span class="hlt">Bubble</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Simoson, Andrew; Wentzky, Bethany</p> <p>2011-01-01</p> <p>Freely <span class="hlt">rising</span> air <span class="hlt">bubbles</span> in water sometimes assume the shape of a spherical cap, a shape also known as the "big <span class="hlt">bubble</span>". Is it possible to find some objective function involving a combination of a <span class="hlt">bubble</span>'s attributes for which the big <span class="hlt">bubble</span> is the optimal shape? Following the basic idea of the definite integral, we define a <span class="hlt">bubble</span>'s surface as…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28946511','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28946511"><span>Study on <span class="hlt">characteristics</span> of single cavitation <span class="hlt">bubble</span> considering condensation and evaporation of kerosene steam under ultrasonic vibration honing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ye, Linzheng; Zhu, Xijing; Wang, Lujie; Guo, Ce</p> <p>2018-01-01</p> <p>Ultrasonic vibration honing technology is an effective means for materials difficult to machine, where cavitation occurs in grinding fluid under the action of ultrasound. To investigate the changes of single cavitation <span class="hlt">bubble</span> <span class="hlt">characteristics</span> in the grinding area and how honing parameters influence <span class="hlt">bubble</span> <span class="hlt">characteristics</span>, a dynamic model of single cavitation <span class="hlt">bubble</span> in the ultrasonic vibration honing grinding area was established. The model was based on the <span class="hlt">bubble</span> dynamics and considered the condensation and evaporation of kerosene steam and honing processing environment. The change rules of <span class="hlt">bubble</span> radius, temperature, pressure and number of kerosene steam molecules inside the <span class="hlt">bubble</span> were numerically simulated in the process of <span class="hlt">bubble</span> moving. The results show that the condensation and evaporation of kerosene steam can help to explain the changes of temperature and pressure inside the <span class="hlt">bubble</span>. Compared with ultrasonic vibration, the amplitude of <span class="hlt">bubble</span> radius is greatly suppressed in the ultrasonic honing environment. However, the rate of movement of the <span class="hlt">bubble</span> is faster. Meanwhile, the minimum values of pressure and temperature are larger, and the number of kerosene steam molecules is less. By studying the effect of honing factors on the movement of the cavitation <span class="hlt">bubble</span>, it is found that honing pressure has a greater influence on <span class="hlt">bubble</span> evolution <span class="hlt">characteristics</span>, while rotation speed of honing head has a minor effect and the reciprocating speed of honing head has little impacts. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MMTA...49.2193H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MMTA...49.2193H"><span>Prediction of Cavitation Depth in an Al-Cu Alloy Melt with <span class="hlt">Bubble</span> <span class="hlt">Characteristics</span> Based on Synchrotron X-ray Radiography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Haijun; Shu, Da; Fu, Yanan; Zhu, Guoliang; Wang, Donghong; Dong, Anping; Sun, Baode</p> <p>2018-06-01</p> <p>The size of cavitation region is a key parameter to estimate the metallurgical effect of ultrasonic melt treatment (UST) on preferential structure refinement. We present a simple numerical model to predict the <span class="hlt">characteristic</span> length of the cavitation region, termed cavitation depth, in a metal melt. The model is based on wave propagation with acoustic attenuation caused by cavitation <span class="hlt">bubbles</span> which are dependent on <span class="hlt">bubble</span> <span class="hlt">characteristics</span> and ultrasonic intensity. In situ synchrotron X-ray imaging of cavitation <span class="hlt">bubbles</span> has been made to quantitatively measure the size of cavitation region and volume fraction and size distribution of cavitation <span class="hlt">bubbles</span> in an Al-Cu melt. The results show that cavitation <span class="hlt">bubbles</span> maintain a log-normal size distribution, and the volume fraction of cavitation <span class="hlt">bubbles</span> obeys a tanh function with the applied ultrasonic intensity. Using the experimental values of <span class="hlt">bubble</span> <span class="hlt">characteristics</span> as input, the predicted cavitation depth agrees well with observations except for a slight deviation at higher acoustic intensities. Further analysis shows that the increase of <span class="hlt">bubble</span> volume and <span class="hlt">bubble</span> size both leads to higher attenuation by cavitation <span class="hlt">bubbles</span>, and hence, smaller cavitation depth. The current model offers a guideline to implement UST, especially for structural refinement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MMTA..tmp.1486H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MMTA..tmp.1486H"><span>Prediction of Cavitation Depth in an Al-Cu Alloy Melt with <span class="hlt">Bubble</span> <span class="hlt">Characteristics</span> Based on Synchrotron X-ray Radiography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Haijun; Shu, Da; Fu, Yanan; Zhu, Guoliang; Wang, Donghong; Dong, Anping; Sun, Baode</p> <p>2018-04-01</p> <p>The size of cavitation region is a key parameter to estimate the metallurgical effect of ultrasonic melt treatment (UST) on preferential structure refinement. We present a simple numerical model to predict the <span class="hlt">characteristic</span> length of the cavitation region, termed cavitation depth, in a metal melt. The model is based on wave propagation with acoustic attenuation caused by cavitation <span class="hlt">bubbles</span> which are dependent on <span class="hlt">bubble</span> <span class="hlt">characteristics</span> and ultrasonic intensity. In situ synchrotron X-ray imaging of cavitation <span class="hlt">bubbles</span> has been made to quantitatively measure the size of cavitation region and volume fraction and size distribution of cavitation <span class="hlt">bubbles</span> in an Al-Cu melt. The results show that cavitation <span class="hlt">bubbles</span> maintain a log-normal size distribution, and the volume fraction of cavitation <span class="hlt">bubbles</span> obeys a tanh function with the applied ultrasonic intensity. Using the experimental values of <span class="hlt">bubble</span> <span class="hlt">characteristics</span> as input, the predicted cavitation depth agrees well with observations except for a slight deviation at higher acoustic intensities. Further analysis shows that the increase of <span class="hlt">bubble</span> volume and <span class="hlt">bubble</span> size both leads to higher attenuation by cavitation <span class="hlt">bubbles</span>, and hence, smaller cavitation depth. The current model offers a guideline to implement UST, especially for structural refinement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27150764','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27150764"><span>Experimental investigation on dynamic <span class="hlt">characteristics</span> and strengthening mechanism of laser-induced cavitation <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ren, X D; He, H; Tong, Y Q; Ren, Y P; Yuan, S Q; Liu, R; Zuo, C Y; Wu, K; Sui, S; Wang, D S</p> <p>2016-09-01</p> <p>The dynamic features of nanosecond laser-induced cavitation <span class="hlt">bubbles</span> near the light alloy boundary were investigated with the high-speed photography. The shock-waves and the dynamic <span class="hlt">characteristics</span> of the cavitation <span class="hlt">bubbles</span> generated by the laser were detected using the hydrophone. The dynamic features and strengthening mechanism of cavitation <span class="hlt">bubbles</span> were studied. The strengthening mechanisms of cavitation <span class="hlt">bubble</span> were discussed when the relative distance parameter γ was within the range of 0.5-2.5. It showed that the strengthening mechanisms caused by liquid jet or shock-waves depended on γ much. The research results provided a new strengthening method based on laser-induced cavitation shotless peening (CSP). Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/7763940','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/7763940"><span>Effect of polymer additives on hydrodynamics and oxygen transfer in a <span class="hlt">bubble</span> column bioreactor.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kawase, Y</p> <p>1993-01-01</p> <p>The influence of polymer additives (polyethylene oxide and polyacrylamide) on the hydrodynamics and oxygen transfer in a <span class="hlt">bubble</span> column bioreactor was examined. The addition of small amounts of these polymers has been known to cause significant drag reduction in turbulent flow circumstances. The gas hold-up was slightly decreased and the liquid-phase mixing was somewhat enhanced due to the addition of the polymers. The addition of polymer additives brought about a reduction of the volumetric oxygen transfer coefficient by about 40%. In dilute polymer solutions, large <span class="hlt">bubbles</span> formed by <span class="hlt">bubble</span> coalescence moved with high <span class="hlt">rise</span> velocities in the presence of many small <span class="hlt">bubbles</span> and the <span class="hlt">bubble</span> size distributions were less uniform compared with those in water. The complicated changes in <span class="hlt">bubble</span> hydrodynamic <span class="hlt">characteristics</span> were examined to give possible explanations for oxygen transfer reduction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMOS12A..06C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMOS12A..06C"><span>Study of CO2 <span class="hlt">bubble</span> dynamics in seawater from QICS field Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, B.; Dewar, M.; Sellami, N.; Stahl, H.; Blackford, J.</p> <p>2011-12-01</p> <p>One of the concerns of employing CCS at engineering scale is the risk of leakage of storage CO2 on the environment and especially on the marine life. QICS, a scientific research project was launched with an aim to study the effects of a potential leak from a CCS system on the UK marine environment [1]. The project involves the injection of CO2 from a shore-based lab into shallow marine sediments. One of the main objectives of the project is to generate experimental data to be compared with the developed physical models. The results of the models are vital for the biogeochemical and ecological models in order to predict the impact of a CO2 leak in a variety of situations. For the evaluation of the fate of the CO2 <span class="hlt">bubbles</span> into the surrounding seawater, the physical model requires two key parameters to be used as input which are: (i) a correlation of the drag coefficient as function of the CO2 <span class="hlt">bubble</span> Reynolds number and (ii) the CO2 <span class="hlt">bubble</span> size distribution. By precisely measuring the CO2 <span class="hlt">bubble</span> size and <span class="hlt">rising</span> speed, these two parameters can be established. For this purpose, the dynamical <span class="hlt">characteristics</span> of the <span class="hlt">rising</span> CO2 <span class="hlt">bubbles</span> in Scottish seawater were investigated experimentally within the QICS project. Observations of the CO2 <span class="hlt">bubbles</span> plume <span class="hlt">rising</span> freely in the in seawater column were captured by video survey using a ruler positioned at the leakage pockmark as dimension reference. This observation made it possible, for the first time, to discuss the dynamics of the CO2 <span class="hlt">bubbles</span> released in seawater. [1] QICS, QICS: Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage. (Accessed 15.07.13), http://www.bgs.ac.uk/qics/home.html</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS12A..06C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS12A..06C"><span>Study of CO2 <span class="hlt">bubble</span> dynamics in seawater from QICS field Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, B.; Dewar, M.; Sellami, N.; Stahl, H.; Blackford, J.</p> <p>2013-12-01</p> <p>One of the concerns of employing CCS at engineering scale is the risk of leakage of storage CO2 on the environment and especially on the marine life. QICS, a scientific research project was launched with an aim to study the effects of a potential leak from a CCS system on the UK marine environment [1]. The project involves the injection of CO2 from a shore-based lab into shallow marine sediments. One of the main objectives of the project is to generate experimental data to be compared with the developed physical models. The results of the models are vital for the biogeochemical and ecological models in order to predict the impact of a CO2 leak in a variety of situations. For the evaluation of the fate of the CO2 <span class="hlt">bubbles</span> into the surrounding seawater, the physical model requires two key parameters to be used as input which are: (i) a correlation of the drag coefficient as function of the CO2 <span class="hlt">bubble</span> Reynolds number and (ii) the CO2 <span class="hlt">bubble</span> size distribution. By precisely measuring the CO2 <span class="hlt">bubble</span> size and <span class="hlt">rising</span> speed, these two parameters can be established. For this purpose, the dynamical <span class="hlt">characteristics</span> of the <span class="hlt">rising</span> CO2 <span class="hlt">bubbles</span> in Scottish seawater were investigated experimentally within the QICS project. Observations of the CO2 <span class="hlt">bubbles</span> plume <span class="hlt">rising</span> freely in the in seawater column were captured by video survey using a ruler positioned at the leakage pockmark as dimension reference. This observation made it possible, for the first time, to discuss the dynamics of the CO2 <span class="hlt">bubbles</span> released in seawater. [1] QICS, QICS: Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage. (Accessed 15.07.13), http://www.bgs.ac.uk/qics/home.html</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMOS13D1565L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMOS13D1565L"><span>Methane <span class="hlt">rising</span> from the Deep: Hydrates, <span class="hlt">Bubbles</span>, Oil Spills, and Global Warming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leifer, I.; Rehder, G. J.; Solomon, E. A.; Kastner, M.; Asper, V. L.; Joye, S. B.</p> <p>2011-12-01</p> <p>Elevated methane concentrations in near-surface waters and the atmosphere have been reported for seepage from depths of nearly 1 km at the Gulf of Mexico hydrate observatory (MC118), suggesting that for some methane sources, deepsea methane is not trapped and can contribute to atmospheric greenhouse gas budgets. Ebullition is key with important sensitivity to the formation of hydrate skins and oil coatings, high-pressure solubility, <span class="hlt">bubble</span> size and <span class="hlt">bubble</span> plume processes. <span class="hlt">Bubble</span> ROV tracking studies showed survival to near thermocline depths. Studies with a numerical <span class="hlt">bubble</span> propagation model demonstrated that consideration of structure I hydrate skins transported most methane only to mid-water column depths. Instead, consideration of structure II hydrates, which are stable to far shallower depths and appropriate for natural gas mixtures, allows <span class="hlt">bubbles</span> to survive to far shallower depths. Moreover, model predictions of vertical methane and alkane profiles and <span class="hlt">bubble</span> size evolution were in better agreement with observations after consideration of structure II hydrate properties as well as an improved implementation of plume properties, such as currents. These results demonstrate the importance of correctly incorporating <span class="hlt">bubble</span> hydrate processes in efforts to predict the impact of deepsea seepage as well as to understand the fate of <span class="hlt">bubble</span>-transported oil and methane from deepsea pipeline leaks and well blowouts. Application to the DWH spill demonstrated the importance of deepsea processes to the fate of spilled subsurface oil. Because several of these parameters vary temporally (<span class="hlt">bubble</span> flux, currents, temperature), sensitivity studies indicate the importance of real-time monitoring data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDA21008M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDA21008M"><span><span class="hlt">Bubble</span> Size Distribution in a Vibrating <span class="hlt">Bubble</span> Column</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohagheghian, Shahrouz; Wilson, Trevor; Valenzuela, Bret; Hinds, Tyler; Moseni, Kevin; Elbing, Brian</p> <p>2016-11-01</p> <p>While vibrating <span class="hlt">bubble</span> columns have increased the mass transfer between phases, a universal scaling law remains elusive. Attempts to predict mass transfer rates in large industrial scale applications by extrapolating laboratory scale models have failed. In a stationary <span class="hlt">bubble</span> column, mass transfer is a function of phase interfacial area (PIA), while PIA is determined based on the <span class="hlt">bubble</span> size distribution (BSD). On the other hand, BSD is influenced by the injection <span class="hlt">characteristics</span> and liquid phase dynamics and properties. Vibration modifies the BSD by impacting the gas and gas-liquid dynamics. This work uses a vibrating cylindrical <span class="hlt">bubble</span> column to investigate the effect of gas injection and vibration <span class="hlt">characteristics</span> on the BSD. The <span class="hlt">bubble</span> column has a 10 cm diameter and was filled with water to a depth of 90 cm above the tip of the orifice tube injector. BSD was measured using high-speed imaging to determine the projected area of individual <span class="hlt">bubbles</span>, which the nominal <span class="hlt">bubble</span> diameter was then calculated assuming spherical <span class="hlt">bubbles</span>. The BSD dependence on the distance from the injector, injector design (1.6 and 0.8 mm ID), air flow rates (0.5 to 5 lit/min), and vibration conditions (stationary and vibration conditions varying amplitude and frequency) will be presented. In addition to mean data, higher order statistics will also be provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22408940','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22408940"><span><span class="hlt">Characteristics</span> of carbon nanotubes based micro-<span class="hlt">bubble</span> generator for thermal jet printing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Wenli; Li, Yupeng; Sun, Weijun; Wang, Yunbo; Zhu, Chao</p> <p>2011-12-01</p> <p>We propose a conceptional thermal printhead with dual microbubble generators mounted parallel in each nozzle chamber, where multiwalled carbon nanotubes are adopted as heating elements with much higher energy efficiency than traditional approaches using noble metals or polysilicon. Tailing effect of droplet can be excluded by appropriate control of grouped <span class="hlt">bubble</span> generations. <span class="hlt">Characteristics</span> of the corresponding micro-fabricated microbubble generators were comprehensively studied before the formation of printhead. Electrical properties of the microheaters on glass substrate in air and performance of <span class="hlt">bubble</span> generation underwater focusing on the relationships between input power, device resistance and <span class="hlt">bubble</span> behavior were probed. Proof-of-concept <span class="hlt">bubble</span> generations grouped to eliminate the tailing effect of droplet were performed indicating precise pattern with high resolution could be realized by this kind of printhead. Experimental results revealed guidance to the geometric design of the printhead as well as its fabrication margin and the electrical control of the microbubble generators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDR35004S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDR35004S"><span>Approaching behavior of a pair of spherical <span class="hlt">bubbles</span> in quiescent liquids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanada, Toshiyuki; Kusuno, Hiroaki</p> <p>2015-11-01</p> <p>Some unique motions related <span class="hlt">bubble-bubble</span> interaction, such as equilibrium distance, wake induced lift force, have been proposed by theoretical analysis or numerical simulations. These motions are different from the solid spheres like DKT model (Drafting, Kissing and Tumbling). However, there is a lack of the experimental verification. In this study, we experimentally investigated the motion of a pair of <span class="hlt">bubbles</span> initially positioned in-line configuration in ultrapure water or an aqueous surfactant solution. The <span class="hlt">bubble</span> motion were observed by two high speed video cameras. The <span class="hlt">bubbles</span> Reynolds number was ranged from 50 to 300 and <span class="hlt">bubbles</span> hold the spherical shape in this range. In ultrapure water, initially the trailing <span class="hlt">bubble</span> deviated from the vertical line on the leading <span class="hlt">bubble</span> owing to the wake of the leading <span class="hlt">bubble</span>. And then, the slight difference of the <span class="hlt">bubble</span> radius changed the relative motion. When the trailing <span class="hlt">bubble</span> slightly larger than the leading <span class="hlt">bubble</span>, the trailing <span class="hlt">bubble</span> approached to the leading <span class="hlt">bubble</span> due to it's buoyancy difference. The <span class="hlt">bubbles</span> attracted and collided only when the <span class="hlt">bubbles</span> <span class="hlt">rising</span> approximately side by side configuration. In addition, we will also discuss the motion of <span class="hlt">bubbles</span> <span class="hlt">rising</span> in an aqueous surfactant solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16003969','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16003969"><span>The relationship between critical flux and fibre movement induced by <span class="hlt">bubbling</span> in a submerged hollow fibre system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wicaksana, F; Fan, A G; Chen, V</p> <p>2005-01-01</p> <p><span class="hlt">Bubbling</span> has been used to enhance various processes. In this paper we deal with the effect of <span class="hlt">bubbling</span> on submerged hollow fibre membranes, where <span class="hlt">bubbling</span> is applied to prevent severe membrane fouling. Previous work with submerged hollow fibres has observed that significant fibre movement can be induced by <span class="hlt">bubbling</span> and that there is a qualitative relationship between fibre movement and filtration performance. Therefore, the aim of the present research has been to analyse the link between <span class="hlt">bubbling</span>, fibre movement and critical flux, identified as the flux at which the transmembrane pressure (TMP) starts to <span class="hlt">rise</span>. Tests were performed on vertical isolated fibres with a model feed of yeast suspension. The fibres were subject to steady <span class="hlt">bubbling</span> from below. The parameters of interest were the fibre <span class="hlt">characteristics</span>, such as tightness, diameter and length, as well as feed concentration. The results confirmed that the critical fluxes are affected by the fibre <span class="hlt">characteristics</span> and feed concentration. Higher critical flux values can be achieved by using loose fibres, smaller diameters and longer fibres. The enhancement is partially linked to fibre movement and this is confirmed by improved performance when fibres are subject to mechanical movement in the absence of <span class="hlt">bubbling</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPJST.226..117S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPJST.226..117S"><span>Effervescence in champagne and sparkling wines: From <span class="hlt">bubble</span> bursting to droplet evaporation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Séon, T.; Liger-Belair, G.</p> <p>2017-01-01</p> <p>When a <span class="hlt">bubble</span> reaches an air-liquid interface, it ruptures, projecting a multitude of tiny droplets in the air. Across the oceans, an estimated 1018 to 1020 <span class="hlt">bubbles</span> burst every second, and form the so called sea spray, a major player in earth's climate system. At a smaller scale, in a glass of champagne about a million <span class="hlt">bubbles</span> nucleate on the wall, <span class="hlt">rise</span> towards the surface and burst, giving birth to a particular aerosol that holds a concentrate of wine aromas. Based on the model experiment of a single <span class="hlt">bubble</span> bursting in simple liquids, we depict each step of this effervescence, from <span class="hlt">bubble</span> bursting to drop evaporation. In particular, we propose simple scaling laws for the jet velocity and the top drop size. We unravel experimentally the intricate roles of <span class="hlt">bubble</span> shape, capillary waves, gravity, and liquid properties in the jet dynamics and the drop detachment. We demonstrate how damping action of viscosity produces faster and smaller droplets and more generally how liquid properties enable to control the <span class="hlt">bubble</span> bursting aerosol <span class="hlt">characteristics</span>. In this context, the particular case of Champagne wine aerosol is studied in details and the key features of this aerosol are identified. We demonstrate that compared to a still wine, champagne fizz drastically enhances the transfer of liquid into the atmosphere. Conditions on <span class="hlt">bubble</span> radius and wine viscosity that optimize aerosol evaporation are provided. These results pave the way towards the fine tuning of aerosol <span class="hlt">characteristics</span> and flavor release during sparkling wine tasting, a major issue of the sparkling wine industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..214a2003E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..214a2003E"><span>Theoretical Investigation on Particle Brownian Motion on Micro-air-<span class="hlt">bubble</span> <span class="hlt">Characteristic</span> in H2O Solvent</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eka Putri, Irana; Gita Redhyka, Grace</p> <p>2017-07-01</p> <p>Micro-air-<span class="hlt">bubble</span> has a high potential contribution in waste water, farming, and fishery treatment. In this research, submicron scale of micro-air-<span class="hlt">bubble</span> was observed to determine its stability in H2O solvent. By increasing its stability, it can be used for several applications, such as bio-preservative for medical and food transport. The micro-air-<span class="hlt">bubble</span> was assumed in spherical shape that in incompressible gas boundary condition. So, the random motion of particle (Brownian motion) can be solved by using Stokes-Einstein approximation. But, Hadamard and Rybczynski equation is promoted to solve for larger <span class="hlt">bubble</span> (micro scale). While, the effect of physical properties (e.g. diffusion coefficient, density, and flow rate) have taken important role in its <span class="hlt">characteristics</span> in water. According to the theoretical investigation that have been done, decreasing of <span class="hlt">bubble</span> velocity indicates that the <span class="hlt">bubble</span> dissolves away or shrinking to the surface. To obtain longevity <span class="hlt">bubble</span> in pure water medium, it is recomended to apply some surfactant molecules (e.g. NaCl) in micro-air-<span class="hlt">bubble</span> medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22492642-numerical-investigation-bubble-nonlinear-dynamics-characteristics','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22492642-numerical-investigation-bubble-nonlinear-dynamics-characteristics"><span>Numerical investigation of <span class="hlt">bubble</span> nonlinear dynamics <span class="hlt">characteristics</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Shi, Jie, E-mail: shijie@hrbeu.edu.cn; Yang, Desen; Shi, Shengguo</p> <p>2015-10-28</p> <p>The complicated dynamical behaviors of <span class="hlt">bubble</span> oscillation driven by acoustic wave can provide favorable conditions for many engineering applications. On the basis of Keller-Miksis model, the influences of control parameters, including acoustic frequency, acoustic pressure and radius of gas <span class="hlt">bubble</span>, are discussed by utilizing various numerical analysis methods, Furthermore, the law of power spectral variation is studied. It is shown that the complicated dynamic behaviors of <span class="hlt">bubble</span> oscillation driven by acoustic wave, such as bifurcation and chaos, further the stimulated scattering processes are revealed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F8006T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F8006T"><span>Molecular Dynamics Investigation of Each <span class="hlt">Bubble</span> Behavior in Coarsening of Cavitation <span class="hlt">Bubbles</span> in a Finite Space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsuda, Shin-Ichi; Nakano, Yuta; Watanabe, Satoshi</p> <p>2017-11-01</p> <p>Recently, several studies using Molecular Dynamics (MD) simulation have been conducted for investigation of Ostwald ripening of cavitation <span class="hlt">bubbles</span> in a finite space. The previous studies focused a <span class="hlt">characteristic</span> length of <span class="hlt">bubbles</span> as one of the spatially-averaged quantities, but each <span class="hlt">bubble</span> behavior was not been investigated in detail. The objective of this study is clarification of the <span class="hlt">characteristics</span> of each <span class="hlt">bubble</span> behavior in Ostwald ripening, and we conducted MD simulation of a Lennard-Jones fluid in a semi-confined space. As a result, the time dependency of the <span class="hlt">characteristic</span> length of <span class="hlt">bubbles</span> as a spatially-averaged quantity suggested that the driving force of the Ostwald ripening is Evaporation/Condensation (EC) across liquid-vapor surface, which is the same result as the previous works. The radius change of the relatively larger <span class="hlt">bubbles</span> also showed the same tendency to a classical EC model. However, the sufficiently smaller <span class="hlt">bubbles</span> than the critical size, e.g., the <span class="hlt">bubbles</span> just before collapsing, showed a different <span class="hlt">characteristic</span> from the classical EC model. Those smaller <span class="hlt">bubbles</span> has a tendency to be limited by mechanical non-equilibrium in which viscosity of liquid is dominant rather than by EC across liquid-vapor surface. This work was supported by JSPS KAKENHI Grant Number JP16K06085.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFD.D9001H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFD.D9001H"><span>Taylor <span class="hlt">bubbles</span> at high viscosity ratios: experiments and numerical simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hewakandamby, Buddhika; Hasan, Abbas; Azzopardi, Barry; Xie, Zhihua; Pain, Chris; Matar, Omar</p> <p>2015-11-01</p> <p>The Taylor <span class="hlt">bubble</span> is a single long <span class="hlt">bubble</span> which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of this study is to investigate the fluid dynamics of three-dimensional Taylor <span class="hlt">bubble</span> <span class="hlt">rising</span> in highly viscous silicone oil in a vertical pipe. An adaptive unstructured mesh modelling framework is adopted here which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of <span class="hlt">bubble</span> <span class="hlt">rising</span> and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a `volume of fluid'-type method for the interface-capturing based on a compressive control volume advection method, and a force-balanced algorithm for the surface tension implementation. Experimental results for the Taylor <span class="hlt">bubble</span> shape and <span class="hlt">rise</span> velocity are presented, together with numerical results for the dynamics of the <span class="hlt">bubbles</span>. A comparison of the simulation predictions with experimental data available in the literature is also presented to demonstrate the capabilities of our numerical method. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25455807','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25455807"><span>Dynamics of Rear Stagnant Cap formation at the surface of spherical <span class="hlt">bubbles</span> <span class="hlt">rising</span> in surfactant solutions at large Reynolds numbers under conditions of small Marangoni number and slow sorption kinetics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dukhin, S S; Kovalchuk, V I; Gochev, G G; Lotfi, M; Krzan, M; Malysa, K; Miller, R</p> <p>2015-08-01</p> <p>On the surface of <span class="hlt">bubbles</span> <span class="hlt">rising</span> in a surfactant solution the adsorption process proceeds and leads to the formation of a so called Rear Stagnant Cap (RSC). The larger this RSC is the stronger is the retardation of the <span class="hlt">rising</span> velocity. The theory of a steady RSC and steady retarded <span class="hlt">rising</span> velocity, which sets in after a transient stage, has been generally accepted. However, a non-steady process of <span class="hlt">bubble</span> <span class="hlt">rising</span> starting from the initial zero velocity represents an important portion of the trajectory of <span class="hlt">rising</span>, characterized by a local velocity profile (LVP). As there is no theory of RSC growth for large Reynolds numbers Re » 1 so far, the interpretation of LVPs measured in this regime was impossible. It turned out, that an analytical theory for a quasi-steady growth of RSC is possible for small Marangoni numbers Ma « 1, i.e. when the RSC is almost completely compressed, which means a uniform surface concentration Γ(θ)=Γ(∞) within the RSC. Hence, the RSC angle ψ(t) is obtained as a function of the adsorption isotherm parameters and time t. From the steady velocity v(st)(ψ), the dependence of non-steady velocity on time is obtained by employing v(st)[ψ(t)] via a quasi-steady approximation. The measurement of LVP creates a promising new opportunity for investigation of the RSC dynamics and adsorption kinetics. While adsorption and desorption happen at the same localization in the classical methods, in <span class="hlt">rising</span> <span class="hlt">bubble</span> experiments desorption occurs mainly within RSC while adsorption on the mobile part of the <span class="hlt">bubble</span> surface. The desorption flux from RSC is proportional to αΓ(∞), while it is usually αΓ. The adsorption flux at the mobile surface above RSC can be assumed proportional to βC0, while it is usually βC0(1-Γ/Γ(∞)). These simplifications may become favorable in investigations of the adsorption kinetics for larger molecules, in particular for globular proteins, which essentially stay at an interface once adsorbed. Copyright © 2014 Elsevier B</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050186639&hterms=nitrous+oxide+production&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dnitrous%2Boxide%2Bproduction','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050186639&hterms=nitrous+oxide+production&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dnitrous%2Boxide%2Bproduction"><span><span class="hlt">Bubble</span> Combustion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Corrigan, Jackie</p> <p>2004-01-01</p> <p>A method of energy production that is capable of low pollutant emissions is fundamental to one of the four pillars of NASA s Aeronautics Blueprint: Revolutionary Vehicles. <span class="hlt">Bubble</span> combustion, a new engine technology currently being developed at Glenn Research Center promises to provide low emissions combustion in support of NASA s vision under the Emissions Element because it generates power, while minimizing the production of carbon dioxide (CO2) and nitrous oxides (NOx), both known to be Greenhouse gases. and allows the use of alternative fuels such as corn oil, low-grade fuels, and even used motor oil. <span class="hlt">Bubble</span> combustion is analogous to the inverse of spray combustion: the difference between <span class="hlt">bubble</span> and spray combustion is that spray combustion is spraying a liquid in to a gas to form droplets, whereas <span class="hlt">bubble</span> combustion involves injecting a gas into a liquid to form gaseous <span class="hlt">bubbles</span>. In <span class="hlt">bubble</span> combustion, the process for the ignition of the <span class="hlt">bubbles</span> takes place on a time scale of less than a nanosecond and begins with acoustic waves perturbing each <span class="hlt">bubble</span>. This perturbation causes the local pressure to drop below the vapor pressure of the liquid thus producing cavitation in which the <span class="hlt">bubble</span> diameter grows, and upon reversal of the oscillating pressure field, the <span class="hlt">bubble</span> then collapses rapidly with the aid of the high surface tension forces acting on the wall of the <span class="hlt">bubble</span>. The rapid and violent collapse causes the temperatures inside the <span class="hlt">bubbles</span> to soar as a result of adiabatic heating. As the temperatures <span class="hlt">rise</span>, the gaseous contents of the <span class="hlt">bubble</span> ignite with the <span class="hlt">bubble</span> itself serving as its own combustion chamber. After ignition, this is the time in the <span class="hlt">bubble</span> s life cycle where power is generated, and CO2, and NOx among other species, are produced. However, the pollutants CO2 and NOx are absorbed into the surrounding liquid. The importance of <span class="hlt">bubble</span> combustion is that it generates power using a simple and compact device. We conducted a parametric study using CAVCHEM</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JCoPh.347..261W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JCoPh.347..261W"><span>Advanced subgrid-scale modeling for convection-dominated species transport at fluid interfaces with application to mass transfer from <span class="hlt">rising</span> <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weiner, Andre; Bothe, Dieter</p> <p>2017-10-01</p> <p>This paper presents a novel subgrid scale (SGS) model for simulating convection-dominated species transport at deformable fluid interfaces. One possible application is the Direct Numerical Simulation (DNS) of mass transfer from <span class="hlt">rising</span> <span class="hlt">bubbles</span>. The transport of a dissolving gas along the <span class="hlt">bubble</span>-liquid interface is determined by two transport phenomena: convection in streamwise direction and diffusion in interface normal direction. The convective transport for technical <span class="hlt">bubble</span> sizes is several orders of magnitude higher, leading to a thin concentration boundary layer around the <span class="hlt">bubble</span>. A true DNS, fully resolving hydrodynamic and mass transfer length scales results in infeasible computational costs. Our approach is therefore a DNS of the flow field combined with a SGS model to compute the mass transfer between <span class="hlt">bubble</span> and liquid. An appropriate model-function is used to compute the numerical fluxes on all cell faces of an interface cell. This allows to predict the mass transfer correctly even if the concentration boundary layer is fully contained in a single cell layer around the interface. We show that the SGS-model reduces the resolution requirements at the interface by a factor of ten and more. The integral flux correction is also applicable to other thin boundary layer problems. Two flow regimes are investigated to validate the model. A semi-analytical solution for creeping flow is used to assess local and global mass transfer quantities. For higher Reynolds numbers ranging from Re = 100 to Re = 460 and Péclet numbers between Pe =104 and Pe = 4 ṡ106 we compare the global Sherwood number against correlations from literature. In terms of accuracy, the predicted mass transfer never deviates more than 4% from the reference values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhFl...19j8105A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhFl...19j8105A"><span>Taylor <span class="hlt">bubbles</span> in liquid filled annuli: Some new observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agarwal, V.; Jana, A. K.; Das, G.; Das, P. K.</p> <p>2007-10-01</p> <p>Taylor <span class="hlt">bubbles</span> <span class="hlt">rising</span> through a vertical concentric annulus do not wrap around the inner tube completely. The two edges of the <span class="hlt">bubble</span> are separated by a liquid bridge which increases with an increase of the inner radius. However, the change in the shape of the Taylor <span class="hlt">bubbles</span> in annuli with extremely small inner diameter has not yet been reported. In the present investigation, several experiments have been performed in circular and noncircular annuli to understand the influence of the inner and outer wall on the <span class="hlt">bubble</span> shape. The <span class="hlt">bubble</span> has been observed to assume a completely different shape in both circular and square annuli with a very thin inner rod. Nevertheless, the <span class="hlt">rise</span> velocity for such situations agree with the prediction of the model proposed by Das et al. [Chem. Eng. Sci. 53, 977 (1998)] when the outer pipe is circular but fails for a square outer pipe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.A6004K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.A6004K"><span><span class="hlt">Bubble</span> bursting at an interface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kulkarni, Varun; Sajjad, Kumayl; Anand, Sushant; Fezzaa, Kamel</p> <p>2017-11-01</p> <p><span class="hlt">Bubble</span> bursting is crucial to understanding the life span of <span class="hlt">bubbles</span> at an interface and more importantly the nature of interaction between the bulk liquid and the outside environment from the point of view of chemical and biological material transport. The dynamics of the <span class="hlt">bubble</span> as it <span class="hlt">rises</span> from inside the liquid bulk to its disappearance on the interface after bursting is an intriguing process, many aspects of which are still being explored. In our study, we make detailed high speed imaging measurements to examine carefully the hole initiation and growth in bursting <span class="hlt">bubbles</span> that unearth some interesting features of the process. Previous analyses available in literature are revisited based on our novel experimental visualizations. Using a combination of experiments and theory we investigate the role of various forces during the rupturing process. This work aims to further our current knowledge of <span class="hlt">bubble</span> dynamics at an interface with an aim of predicting better the <span class="hlt">bubble</span> evolution from its growth to its eventual integration with the liquid bulk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1357617','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1357617"><span>Experimental study on <span class="hlt">bubble</span> dynamics and wall heat transfer arising from a single nucleation site at subcooled flow boiling conditions – Part 2: Data analysis on sliding <span class="hlt">bubble</span> <span class="hlt">characteristics</span> and associated wall heat transfer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Yooa, Junsoo; Estrada-Perez, Carlos E.; Hassan, Yassin A.</p> <p></p> <p>In this second of two companion papers presents an analysis of sliding <span class="hlt">bubble</span> and wall heat transfer parameters measured during subcooled boiling in a square, vertical, upward flow channel. <span class="hlt">Bubbles</span> were generated only from a single nucleation site for better observation of both the sliding bubbles’ <span class="hlt">characteristics</span> and their impact on wall heat transfer through optical measurement techniques. Specific interests include: (i) <span class="hlt">bubbles</span> departure and subsequent growth while sliding, (ii) <span class="hlt">bubbles</span> release frequency, (iii) coalescence of sliding <span class="hlt">bubbles</span>, (iv) sliding <span class="hlt">bubbles</span> velocity, (v) <span class="hlt">bubbles</span> size distribution and (vi) wall heat transfer influenced by sliding <span class="hlt">bubbles</span>. Our results showed that slidingmore » <span class="hlt">bubbles</span> involve two distinct growth behaviors: (i) at low mass fluxes, sliding <span class="hlt">bubbles</span> grew fast near the nucleation site, subsequently shrank, and then grew again, (ii) as mass flux increased, however, sliding <span class="hlt">bubbles</span> grew more steadily. The <span class="hlt">bubbles</span> originating from the single nucleation site coalesced frequently while sliding, which showed close relation with <span class="hlt">bubbles</span> release frequency. The sliding <span class="hlt">bubble</span> velocity near the nucleation site consistently decreased by increasing mass flux, while the observation often became reversed as the <span class="hlt">bubbles</span> slid downstream due to the effect of interfacial drag. The sliding <span class="hlt">bubbles</span> moved faster than the local liquid (i.e., ur<0) at low mass flux conditions, but it became reversed as the mass flux increased. The size distribution of sliding <span class="hlt">bubbles</span> followed Gaussian distribution well both near and far from the nucleation site. The standard deviation of <span class="hlt">bubble</span> size varied insignificantly through sliding compared to the changes in mean <span class="hlt">bubble</span> size. Lastly, the sliding <span class="hlt">bubbles</span> enhanced the wall heat transfer and the effect became more noticeable as inlet subcooling/mass flux decreased or wall heat flux increased. Particularly, the sliding <span class="hlt">bubble</span> <span class="hlt">characteristics</span> such as <span class="hlt">bubble</span> growth behavior observed near the nucleation site played</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1357617-experimental-study-bubble-dynamics-wall-heat-transfer-arising-from-single-nucleation-site-subcooled-flow-boiling-conditions-part-data-analysis-sliding-bubble-characteristics-associated-wall-heat-transfer','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1357617-experimental-study-bubble-dynamics-wall-heat-transfer-arising-from-single-nucleation-site-subcooled-flow-boiling-conditions-part-data-analysis-sliding-bubble-characteristics-associated-wall-heat-transfer"><span>Experimental study on <span class="hlt">bubble</span> dynamics and wall heat transfer arising from a single nucleation site at subcooled flow boiling conditions – Part 2: Data analysis on sliding <span class="hlt">bubble</span> <span class="hlt">characteristics</span> and associated wall heat transfer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Yooa, Junsoo; Estrada-Perez, Carlos E.; Hassan, Yassin A.</p> <p>2016-04-28</p> <p>In this second of two companion papers presents an analysis of sliding <span class="hlt">bubble</span> and wall heat transfer parameters measured during subcooled boiling in a square, vertical, upward flow channel. <span class="hlt">Bubbles</span> were generated only from a single nucleation site for better observation of both the sliding bubbles’ <span class="hlt">characteristics</span> and their impact on wall heat transfer through optical measurement techniques. Specific interests include: (i) <span class="hlt">bubbles</span> departure and subsequent growth while sliding, (ii) <span class="hlt">bubbles</span> release frequency, (iii) coalescence of sliding <span class="hlt">bubbles</span>, (iv) sliding <span class="hlt">bubbles</span> velocity, (v) <span class="hlt">bubbles</span> size distribution and (vi) wall heat transfer influenced by sliding <span class="hlt">bubbles</span>. Our results showed that slidingmore » <span class="hlt">bubbles</span> involve two distinct growth behaviors: (i) at low mass fluxes, sliding <span class="hlt">bubbles</span> grew fast near the nucleation site, subsequently shrank, and then grew again, (ii) as mass flux increased, however, sliding <span class="hlt">bubbles</span> grew more steadily. The <span class="hlt">bubbles</span> originating from the single nucleation site coalesced frequently while sliding, which showed close relation with <span class="hlt">bubbles</span> release frequency. The sliding <span class="hlt">bubble</span> velocity near the nucleation site consistently decreased by increasing mass flux, while the observation often became reversed as the <span class="hlt">bubbles</span> slid downstream due to the effect of interfacial drag. The sliding <span class="hlt">bubbles</span> moved faster than the local liquid (i.e., ur<0) at low mass flux conditions, but it became reversed as the mass flux increased. The size distribution of sliding <span class="hlt">bubbles</span> followed Gaussian distribution well both near and far from the nucleation site. The standard deviation of <span class="hlt">bubble</span> size varied insignificantly through sliding compared to the changes in mean <span class="hlt">bubble</span> size. Lastly, the sliding <span class="hlt">bubbles</span> enhanced the wall heat transfer and the effect became more noticeable as inlet subcooling/mass flux decreased or wall heat flux increased. Particularly, the sliding <span class="hlt">bubble</span> <span class="hlt">characteristics</span> such as <span class="hlt">bubble</span> growth behavior observed near the nucleation site played</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1355810-blowing-magnetic-skyrmion-bubbles','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1355810-blowing-magnetic-skyrmion-bubbles"><span>Blowing magnetic skyrmion <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Jiang, Wanjun; Upadhyaya, Pramey; Zhang, Wei; ...</p> <p>2015-06-11</p> <p>The formation of soap <span class="hlt">bubbles</span> from thin films is accompanied by topological transitions. In this paper, we show how a magnetic topological structure, a skyrmion <span class="hlt">bubble</span>, can be generated in a solid-state system in a similar manner. Using an inhomogeneous in-plane current in a system with broken inversion symmetry, we experimentally “blow” magnetic skyrmion <span class="hlt">bubbles</span> from a geometrical constriction. The presence of a spatially divergent spin-orbit torque gives <span class="hlt">rise</span> to instabilities of the magnetic domain structures that are reminiscent of Rayleigh-Plateau instabilities in fluid flows. We determine a phase diagram for skyrmion formation and reveal the efficient manipulation of thesemore » dynamically created skyrmions, including depinning and motion. Finally, the demonstrated current-driven transformation from stripe domains to magnetic skyrmion <span class="hlt">bubbles</span> could lead to progress in skyrmion-based spintronics.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoMP..171...32B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoMP..171...32B"><span><span class="hlt">Bubble</span> migration in a compacting crystal-liquid mush</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boudreau, Alan</p> <p>2016-04-01</p> <p>Recent theoretical models have suggested that <span class="hlt">bubbles</span> are unlikely to undergo significant migration in a compaction crystal mush by capillary invasion while the system remains partly molten. To test this, experiments of <span class="hlt">bubble</span> migration during compaction in a crystal-liquid mush were modeled using deformable foam crystals in corn syrup in a volumetric burette, compacted with rods of varying weights. A <span class="hlt">bubble</span> source was provided by sodium bicarbonate (Alka-Seltzer®). Large <span class="hlt">bubbles</span> (>several crystal sizes) are pinched by the compacting matrix and become overpressured and deformed as the <span class="hlt">bubbles</span> experience a load change from hydrostatic to lithostatic. Once they begin to move, they move much faster than the compaction-driven liquid. <span class="hlt">Bubbles</span> that are about the same size as the crystals but larger than the narrower pore throats move by deformation or breaking into smaller <span class="hlt">bubbles</span> as they are forced through pore restrictions. <span class="hlt">Bubbles</span> that are less than the typical pore diameter generally move with the liquid: The liquid + <span class="hlt">bubble</span> mixture behaves as a single phase with a lower density than the <span class="hlt">bubble</span>-free liquid, and as a consequence it <span class="hlt">rises</span> faster than <span class="hlt">bubble</span>-free liquid and allows for faster compaction. The overpressure required to force a <span class="hlt">bubble</span> through the matrix (max grain size = 5 mm) is modest, about 5 %, and it is estimated that for a grain size of 1 mm, the required overpressure would be about 25 %. Using apatite distribution in a Stillwater olivine gabbro as an analog for <span class="hlt">bubble</span> nucleation and growth, it is suggested that relatively large <span class="hlt">bubbles</span> initially nucleate and grow in liquid-rich channels that develop late in the compaction history. Overpressure from compaction allows <span class="hlt">bubbles</span> to <span class="hlt">rise</span> higher into hotter parts of the crystal pile, where they redissolve and increase the volatile content of the liquid over what it would have without the <span class="hlt">bubble</span> migration, leading to progressively earlier vapor saturation during crystallization of the interstitial liquid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.6841W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.6841W"><span>Dynamic morphology of gas hydrate on a methane <span class="hlt">bubble</span> in water: Observations and new insights for hydrate film models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Warzinski, Robert P.; Lynn, Ronald; Haljasmaa, Igor; Leifer, Ira; Shaffer, Frank; Anderson, Brian J.; Levine, Jonathan S.</p> <p>2014-10-01</p> <p>Predicting the fate of subsea hydrocarbon gases escaping into seawater is complicated by potential formation of hydrate on <span class="hlt">rising</span> <span class="hlt">bubbles</span> that can enhance their survival in the water column, allowing gas to reach shallower depths and the atmosphere. The precise nature and influence of hydrate coatings on <span class="hlt">bubble</span> hydrodynamics and dissolution is largely unknown. Here we present high-definition, experimental observations of complex surficial mechanisms governing methane <span class="hlt">bubble</span> hydrate formation and dissociation during transit of a simulated oceanic water column that reveal a temporal progression of deep-sea controlling mechanisms. Synergistic feedbacks between <span class="hlt">bubble</span> hydrodynamics, hydrate morphology, and coverage <span class="hlt">characteristics</span> were discovered. Morphological changes on the <span class="hlt">bubble</span> surface appear analogous to macroscale, sea ice processes, presenting new mechanistic insights. An inverse linear relationship between hydrate coverage and <span class="hlt">bubble</span> dissolution rate is indicated. Understanding and incorporating these phenomena into <span class="hlt">bubble</span> and <span class="hlt">bubble</span> plume models will be necessary to accurately predict global greenhouse gas budgets for warming ocean scenarios and hydrocarbon transport from anthropogenic or natural deep-sea eruptions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRC..121.2203W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRC..121.2203W"><span>Observations of <span class="hlt">bubbles</span> in natural seep flares at MC 118 and GC 600 using in situ quantitative imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Binbin; Socolofsky, Scott A.; Breier, John A.; Seewald, Jeffrey S.</p> <p>2016-04-01</p> <p>This paper reports the results of quantitative imaging using a stereoscopic, high-speed camera system at two natural gas seep sites in the northern Gulf of Mexico during the Gulf Integrated Spill Research G07 cruise in July 2014. The cruise was conducted on the E/V Nautilus using the ROV Hercules for in situ observation of the seeps as surrogates for the behavior of hydrocarbon <span class="hlt">bubbles</span> in subsea blowouts. The seeps originated between 890 and 1190 m depth in Mississippi Canyon block 118 and Green Canyon block 600. The imaging system provided qualitative assessment of <span class="hlt">bubble</span> behavior (e.g., breakup and coalescence) and verified the formation of clathrate hydrate skins on all <span class="hlt">bubbles</span> above 1.3 m altitude. Quantitative image analysis yielded the <span class="hlt">bubble</span> size distributions, <span class="hlt">rise</span> velocity, total gas flux, and void fraction, with most measurements conducted from the seafloor to an altitude of 200 m. <span class="hlt">Bubble</span> size distributions fit well to lognormal distributions, with median <span class="hlt">bubble</span> sizes between 3 and 4.5 mm. Measurements of <span class="hlt">rise</span> velocity fluctuated between two ranges: fast-<span class="hlt">rising</span> <span class="hlt">bubbles</span> following helical-type trajectories and <span class="hlt">bubbles</span> <span class="hlt">rising</span> about 40% slower following a zig-zag pattern. <span class="hlt">Rise</span> speed was uncorrelated with hydrate formation, and <span class="hlt">bubbles</span> following both speeds were observed at both sites. Ship-mounted multibeam sonar provided the flare <span class="hlt">rise</span> heights, which corresponded closely with the boundary of the hydrate stability zone for the measured gas compositions. The evolution of <span class="hlt">bubble</span> size with height agreed well with mass transfer rates predicted by equations for dirty <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFDD32002W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFDD32002W"><span>Capillarity-Driven <span class="hlt">Bubble</span> Separations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wollman, Andrew; Weislogel, Mark; Dreyer, Michael</p> <p>2013-11-01</p> <p>Techniques for phase separation in the absence of gravity continue to be sought after 5 decades of space flight. This work focuses on the fundamental problem of gas <span class="hlt">bubble</span> separation in <span class="hlt">bubbly</span> flows through open wedge-shaped channel in a microgravity environment. The <span class="hlt">bubbles</span> appear to <span class="hlt">rise</span> in the channel and coalesce with the free surface. Forces acting on the <span class="hlt">bubble</span> are the combined effects of surface tension, wetting conditions, and geometry; not buoyancy. A single dimensionless group is identified that characterizes the <span class="hlt">bubble</span> behavior and supportive experiments are conducted in a terrestrial laboratory, in a 2.1 second drop tower, and aboard the International Space Station as part of the Capillary Channel Flow (CCF) experiments. The data is organized into regime maps that provide insight on passive phase separations for applications ranging from liquid management aboard spacecraft to lab-on-chip technologies. NASA NNX09AP66A, NASA Oregon Space Grant NNX10AK68H, NASA NNX12AO47A, DLR 50WM0535/0845/1145</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFDE11001D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFDE11001D"><span>How are soap <span class="hlt">bubbles</span> blown? Fluid dynamics of soap <span class="hlt">bubble</span> blowing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davidson, John; Lambert, Lori; Sherman, Erica; Wei, Timothy; Ryu, Sangjin</p> <p>2013-11-01</p> <p>Soap <span class="hlt">bubbles</span> are a common interfacial fluid dynamics phenomenon having a long history of delighting not only children and artists but also scientists. In contrast to the dynamics of liquid droplets in gas and gas <span class="hlt">bubbles</span> in liquid, the dynamics of soap <span class="hlt">bubbles</span> has not been well documented. This is possibly because studying soap <span class="hlt">bubbles</span> is more challenging due to there existing two gas-liquid interfaces. Having the thin-film interface seems to alter the <span class="hlt">characteristics</span> of the <span class="hlt">bubble</span>/drop creation process since the interface has limiting factors such as thickness. Thus, the main objective of this study is to determine how the thin-film interface differentiates soap <span class="hlt">bubbles</span> from gas <span class="hlt">bubbles</span> and liquid drops. To investigate the creation process of soap <span class="hlt">bubbles</span>, we constructed an experimental model consisting of air jet flow and a soap film, which consistently replicates the conditions that a human produces when blowing soap <span class="hlt">bubbles</span>, and examined the interaction between the jet and the soap film using the high-speed videography and the particle image velocimetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnRFM..50...25R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnRFM..50...25R"><span>Agitation, Mixing, and Transfers Induced by <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Risso, Frédéric</p> <p>2018-01-01</p> <p><span class="hlt">Bubbly</span> flows involve <span class="hlt">bubbles</span> randomly distributed within a liquid. At large Reynolds number, they experience an agitation that can combine shear-induced turbulence (SIT), large-scale buoyancy-driven flows, and <span class="hlt">bubble</span>-induced agitation (BIA). The properties of BIA strongly differ from those of SIT. They have been determined from studies of homogeneous swarms of <span class="hlt">rising</span> <span class="hlt">bubbles</span>. Regarding the <span class="hlt">bubbles</span>, agitation is mainly caused by the wake-induced path instability. Regarding the liquid, two contributions must be distinguished. The first one corresponds to the anisotropic flow disturbances generated near the <span class="hlt">bubbles</span>, principally in the vertical direction. The second one is the almost isotropic turbulence induced by the flow instability through a population of <span class="hlt">bubbles</span>, which turns out to be the main cause of horizontal fluctuations. Both contributions generate a k-3 spectral subrange and exponential probability density functions. The subsequent issue will be to understand how BIA interacts with SIT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..DFD.GJ010P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..DFD.GJ010P"><span>Slowing down <span class="hlt">bubbles</span> with sound</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poulain, Cedric; Dangla, Remie; Guinard, Marion</p> <p>2009-11-01</p> <p>We present experimental evidence that a <span class="hlt">bubble</span> moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down even for moderate acoustic pressure. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the <span class="hlt">bubble</span>'s fundamental resonant mode. We render the <span class="hlt">bubble</span>'s oscillations and translational movements using high speed video. We show that radial oscillations (Rayleigh-Plesset type) have no effect on the mean velocity, while above a critical pressure, a parametric type instability (Faraday waves) is triggered and gives <span class="hlt">rise</span> to nonlinear surface oscillations. We evidence that these surface waves are subharmonic and responsible for the <span class="hlt">bubble</span>'s drag increase. When the acoustic intensity is increased, Faraday modes interact and the strongly nonlinear oscillations behave randomly, leading to a random behavior of the <span class="hlt">bubble</span>'s trajectory and consequently to a higher slow down. Our observations may suggest new strategies for <span class="hlt">bubbly</span> flow control, or two-phase microfluidic devices. It might also be applicable to other elastic objects, such as globules, cells or vesicles, for medical applications such as elasticity-based sorting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16968053','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16968053"><span>Champagne experiences various rhythmical <span class="hlt">bubbling</span> regimes in a flute.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liger-Belair, Gérard; Tufaile, Alberto; Jeandet, Philippe; Sartorelli, José-Carlos</p> <p>2006-09-20</p> <p><span class="hlt">Bubble</span> trains are seen <span class="hlt">rising</span> gracefully from a few points on the glass wall (called nucleation sites) whenever champagne is poured into a glass. As time passes during the gas-discharging process, the careful observation of some given <span class="hlt">bubble</span> columns reveals that the interbubble distance may change suddenly, thus revealing different rhythmical <span class="hlt">bubbling</span> regimes. Here, it is reported that the transitions between the different <span class="hlt">bubbling</span> regimes of some nucleation sites during gas discharging is a process which may be ruled by a strong interaction between tiny gas pockets trapped inside the nucleation site and/or also by an interaction between the tiny <span class="hlt">bubbles</span> just blown from the nucleation site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997PhDT........84R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997PhDT........84R"><span>Characterisation of <span class="hlt">bubbles</span> in liquids using acoustic techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramble, David Gary</p> <p>1997-12-01</p> <p>This thesis is concerned with the characterisation of air <span class="hlt">bubbles</span> in a liquid through the use of a range of acoustic techniques, with the ultimate aim of minimising the ambiguity of the result and the complexity of the task. A <span class="hlt">bubble</span> is particularly amenable to detection by using acoustical methods because there usually exists a large acoustic impedance mismatch between the gas/vapour inside the <span class="hlt">bubble</span> and that of the surrounding liquid. The <span class="hlt">bubble</span> also behaves like a single degree-of-freedom oscillator when excited, and as such exhibits a well-defined resonance frequency which is related to its radius. Though techniques which exploit this resonance property of the <span class="hlt">bubble</span> are straightforward to apply, the results are prone to ambiguities as larger <span class="hlt">bubbles</span> can geometrically scatter more sound than a smaller resonant <span class="hlt">bubble</span>. However, these drawbacks can be overcome by using acoustical methods which make use of the nonlinear behaviour of <span class="hlt">bubbles</span>. A particular nonlinear technique monitors the second harmonic emission of the <span class="hlt">bubble</span> which is a global maximum at resonance. In addition, a two- frequency excitation technique is used which involves exciting the <span class="hlt">bubble</span> with a fixed high frequency signal (the imaging signal, ωi) of the order of megahertz, and a lower variable frequency (the pumping signal, ωp) which is tuned to the <span class="hlt">bubble</span>'s resonance. The <span class="hlt">bubble</span> couples these two sound fields together to produce sum-and-difference terms which peak at resonance. The two most promising combination frequency signals involve the coupling of the <span class="hlt">bubble</span>'s fundamental with the imaging frequency to give <span class="hlt">rise</span> to a ωi+ωp signal, and the coupling of a subharmonic signal at half the resonance frequency of the <span class="hlt">bubble</span> to give <span class="hlt">rise</span> to a ωi/pmωp/2 signal. Initially, theory is studied which outlines the advantages and disadvantages of each of the acoustic techniques available. Experiments are then conducted in a large tank of water on simple <span class="hlt">bubble</span> populations, ranging from stationary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007WRR....43.2405S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007WRR....43.2405S"><span>Linear <span class="hlt">bubble</span> plume model for hypolimnetic oxygenation: Full-scale validation and sensitivity analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singleton, V. L.; Gantzer, P.; Little, J. C.</p> <p>2007-02-01</p> <p>An existing linear <span class="hlt">bubble</span> plume model was improved, and data collected from a full-scale diffuser installed in Spring Hollow Reservoir, Virginia, were used to validate the model. The depth of maximum plume <span class="hlt">rise</span> was simulated well for two of the three diffuser tests. Temperature predictions deviated from measured profiles near the maximum plume <span class="hlt">rise</span> height, but predicted dissolved oxygen profiles compared very well with observations. A sensitivity analysis was performed. The gas flow rate had the greatest effect on predicted plume <span class="hlt">rise</span> height and induced water flow rate, both of which were directly proportional to gas flow rate. Oxygen transfer within the hypolimnion was independent of all parameters except initial <span class="hlt">bubble</span> radius and was inversely proportional for radii greater than approximately 1 mm. The results of this work suggest that plume dynamics and oxygen transfer can successfully be predicted for linear <span class="hlt">bubble</span> plumes using the discrete-<span class="hlt">bubble</span> approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/7081779-transformer-overload-bubble-evolution-proceedings','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/7081779-transformer-overload-bubble-evolution-proceedings"><span>Transformer overload and <span class="hlt">bubble</span> evolution: Proceedings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Addis, G.; Lindgren, S.</p> <p>1988-06-01</p> <p>The EPRI workshop on Transformer Overload <span class="hlt">Characteristics</span> and <span class="hlt">Bubble</span> Evolution was held to review the findings of investigations over the past 7-8 years to determine whether enough information is now available for utilities to establish safe loading practices. Sixteen papers were presented, including a utility review, physical and dielectric effects of gas and <span class="hlt">bubble</span> formation from cellulose insulated transformers, transformer life <span class="hlt">characteristics</span>, gas <span class="hlt">bubble</span> studies and impulse test on distribution transformers, mathematical modeling of <span class="hlt">bubble</span> evolution, transformer overload <span class="hlt">characteristics</span>, variation of PD-strength for oil-paper insulation, survey on maximum safe operating hot spot temperature, and overload management. The meeting concluded withmore » a general discussion covering the existing state of knowledge and the need for additional research. Sixteen papers have been cataloged separately.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011OcScD...8.1757S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011OcScD...8.1757S"><span>Technical Note: Detection of gas <span class="hlt">bubble</span> leakage via correlation of water column multibeam images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schneider von Deimling, J.; Papenberg, C.</p> <p>2011-07-01</p> <p>Hydroacoustic detection of natural gas release from the seafloor has been conducted in the past by using singlebeam echosounders. In contrast modern multibeam swath mapping systems allow much wider coverage, higher resolution, and offer 3-D spatial correlation. However, up to the present, the extremely high data rate hampers water column backscatter investigations. More sophisticated visualization and processing techniques for water column backscatter analysis are still under development. We here present such water column backscattering data gathered with a 50 kHz prototype multibeam system. Water column backscattering data is presented in videoframes grabbed over 75 s and a "re-sorted" singlebeam presentation. Thus individual gas <span class="hlt">bubbles</span> <span class="hlt">rising</span> from the 24 m deep seafloor clearly emerge in the acoustic images and <span class="hlt">rise</span> velocities can be determined. A sophisticated processing scheme is introduced to identify those <span class="hlt">rising</span> gas <span class="hlt">bubbles</span> in the hydroacoustic data. It applies a cross-correlation technique similar to that used in Particle Imaging Velocimetry (PIV) to the acoustic backscatter images. Tempo-spatial drift patterns of the <span class="hlt">bubbles</span> are assessed and match very well measured and theoretical <span class="hlt">rise</span> patterns. The application of this processing scheme to our field data gives impressive results with respect to unambiguous <span class="hlt">bubble</span> detection and remote <span class="hlt">bubble</span> <span class="hlt">rise</span> velocimetry. The method can identify and exclude the main driver for misinterpretations, i.e. fish-mediated echoes. Even though image-based cross-correlation techniques are well known in the field of fluid mechanics for high resolution and non-inversive current flow field analysis, this technique was never applied in the proposed sense for an acoustic <span class="hlt">bubble</span> detector.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012OcSci...8..175S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012OcSci...8..175S"><span>Technical Note: Detection of gas <span class="hlt">bubble</span> leakage via correlation of water column multibeam images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schneider von Deimling, J.; Papenberg, C.</p> <p>2012-03-01</p> <p>Hydroacoustic detection of natural gas release from the seafloor has been conducted in the past by using singlebeam echosounders. In contrast, modern multibeam swath mapping systems allow much wider coverage, higher resolution, and offer 3-D spatial correlation. Up to the present, the extremely high data rate hampers water column backscatter investigations and more sophisticated visualization and processing techniques are needed. Here, we present water column backscatter data acquired with a 50 kHz prototype multibeam system over a period of 75 seconds. Display types are of swath-images as well as of a "re-sorted" singlebeam presentation. Thus, individual and/or groups of gas <span class="hlt">bubbles</span> <span class="hlt">rising</span> from the 24 m deep seafloor clearly emerge in the acoustic images, making it possible to estimate <span class="hlt">rise</span> velocities. A sophisticated processing scheme is introduced to identify those <span class="hlt">rising</span> gas <span class="hlt">bubbles</span> in the hydroacoustic data. We apply a cross-correlation technique adapted from particle imaging velocimetry (PIV) to the acoustic backscatter images. Temporal and spatial drift patterns of the <span class="hlt">bubbles</span> are assessed and are shown to match very well to measured and theoretical <span class="hlt">rise</span> patterns. The application of this processing to our field data gives clear results with respect to unambiguous <span class="hlt">bubble</span> detection and remote <span class="hlt">bubble</span> <span class="hlt">rise</span> velocimetry. The method can identify and exclude the main source of misinterpretations, i.e. fish-mediated echoes. Although image-based cross-correlation techniques are well known in the field of fluid mechanics for high resolution and non-inversive current flow field analysis, we present the first application of this technique as an acoustic <span class="hlt">bubble</span> detector.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15823741','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15823741"><span>Elutriation <span class="hlt">characteristics</span> of fine particles from <span class="hlt">bubbling</span> fluidized bed incineration for sludge cake treatment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chang, Yu-Min; Chou, Chih-Mei; Su, Kuo-Tung; Hung, Chao-Yang; Wu, Chao-Hsiung</p> <p>2005-01-01</p> <p>In this study, measurements of elutriation rate were carried out in a bench scale <span class="hlt">bubbling</span> fluidized bed incinerator, which was used to combust sludge cake. The particle size distribution and ignition loss were analyzed to study the elutriation <span class="hlt">characteristics</span> of <span class="hlt">bubbling</span> fluidized bed incineration. Drawn from the experimental data, the elutriation rate constant K(i)* for fine particles were obtained and correlated with parameters. It was found that most of the solid particles (about 95%) elutriated came from the fluidized medium (inorganic matters), but few came from unburned carbon particles or soot (about 5%). Finally, this paper lists a comparison of K(i)* between this study and the published prediction equations derived or studied in non-incineration modes of fluidized bed. A new and modified correlation is proposed here to estimate the elutriation rate of fine particles emitted from a <span class="hlt">bubbling</span> fluidized bed incinerator. Primary operation variables (superficial gas velocity and incineration temperature) affecting the elutriation rate are also discussed in the paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020018887&hterms=surfactants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsurfactants','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020018887&hterms=surfactants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsurfactants"><span>Remobilizing the Interface of Thermocapillary Driven <span class="hlt">Bubbles</span> Retarded By the Adsorption of a Surfactant Impurity on the <span class="hlt">Bubble</span> Surface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Palaparthi, Ravi; Maldarelli, Charles; Papageorgiou, Dimitri; Singh, Bhim (Technical Monitor)</p> <p>2001-01-01</p> <p> molecules which kinetically rapidly exchange between the bulk and the surface and are at high bulk concentrations. Because the remobilizing surfactant is present at much higher concentrations than the impurity, it adsorbs to the <span class="hlt">bubble</span> surface much faster than the impurity when the <span class="hlt">bubble</span> is formed, and thereby prevents the impurity from adsorbing onto the surface. In addition, the rapid kinetic exchange and high bulk concentration maintain a saturated surface with uniform surface concentrations. This prevents retarding surface tension gradients and keeps the thermocapillary velocity high. In our reports over the first 2 years, we presented numerical simulations of the <span class="hlt">bubble</span> motion and surfactant transport which verified theoretically the concept of remobilization, and the development of an apparatus to track and measure the velocity of <span class="hlt">rising</span> <span class="hlt">bubbles</span> in a glycerol/water surfactant solution. This year, we detail experimental observations of remobilization. Two polyethylene oxide surfactants were studied, C12E6 (CH3(CH2)11(OCH2)6OH) and C10E8 (CH3(CH2)4(OCH2CH2)8OH). Measurements of the kinetic exchange for these surfactants show that the one with the longer hydrophobe chain C12E6 has a lower rate of kinetic exchange. In addition, this surfactant is much less soluble in the glycerol/water mixture because of the shorter ethoxylate chain. As a result, we found that C12E6 had only a very limited ability to remobilize <span class="hlt">rising</span> <span class="hlt">bubbles</span> because of the limited kinetic exchange and reduced solubility. However, C10E8, with its higher solubility and more rapid exchange was found to dramatically remobilize <span class="hlt">rising</span> <span class="hlt">bubbles</span>. We also compared our theoretical calculations to the experimental measurements of velocity for both the non-remobilizing and remobilizing surfactants and found excellent agreement. We further observed that for C10E8 at high concentrations, which exceeded the critical micelle concentrations, additional remobilization was measured. In this case the rapid exchange of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/7098532-multiple-bubbles-hele-shaw-cell','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/7098532-multiple-bubbles-hele-shaw-cell"><span>Multiple <span class="hlt">bubbles</span> in a Hele-Shaw cell</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Vasconcelos, G.L.</p> <p></p> <p>A new class of exact solutions is reported for an infinite stream of identical groups of <span class="hlt">bubbles</span> moving with a constant velocity [ital U] in a Hele-Shaw cell when surface tension is neglected. It is suggested that the existence of these solutions might explain some of the complex behavior observed in recent experiments on <span class="hlt">rising</span> <span class="hlt">bubbles</span> in a Hele-Shaw cell. Solutions for a finite number of <span class="hlt">bubbles</span> in a channel are also obtained. In this case, it is shown that solutions with an arbitrary <span class="hlt">bubble</span> velocity [ital U][gt][ital V], where [ital V] is the fluid velocity at infinity, can inmore » general be obtained from a simple transformation of the solutions for [ital U]=2[ital V].« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26486337','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26486337"><span>Droplets, <span class="hlt">Bubbles</span> and Ultrasound Interactions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shpak, Oleksandr; Verweij, Martin; de Jong, Nico; Versluis, Michel</p> <p>2016-01-01</p> <p>The interaction of droplets and <span class="hlt">bubbles</span> with ultrasound has been studied extensively in the last 25 years. Microbubbles are broadly used in diagnostic and therapeutic medical applications, for instance, as ultrasound contrast agents. They have a similar size as red blood cells, and thus are able to circulate within blood vessels. Perfluorocarbon liquid droplets can be a potential new generation of microbubble agents as ultrasound can trigger their conversion into gas <span class="hlt">bubbles</span>. Prior to activation, they are at least five times smaller in diameter than the resulting <span class="hlt">bubbles</span>. Together with the violent nature of the phase-transition, the droplets can be used for local drug delivery, embolotherapy, HIFU enhancement and tumor imaging. Here we explain the basics of <span class="hlt">bubble</span> dynamics, described by the Rayleigh-Plesset equation, <span class="hlt">bubble</span> resonance frequency, damping and quality factor. We show the elegant calculation of the above <span class="hlt">characteristics</span> for the case of small amplitude oscillations by linearizing the equations. The effect and importance of a <span class="hlt">bubble</span> coating and effective surface tension are also discussed. We give the main <span class="hlt">characteristics</span> of the power spectrum of <span class="hlt">bubble</span> oscillations. Preceding <span class="hlt">bubble</span> dynamics, ultrasound propagation is introduced. We explain the speed of sound, nonlinearity and attenuation terms. We examine <span class="hlt">bubble</span> ultrasound scattering and how it depends on the wave-shape of the incident wave. Finally, we introduce droplet interaction with ultrasound. We elucidate the ultrasound-focusing concept within a droplets sphere, droplet shaking due to media compressibility and droplet phase-conversion dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010004356','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010004356"><span>Buoyancy Driven Shear Flows of <span class="hlt">Bubble</span> Suspensions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koch, D. L.; Hill, R. J.; Chellppannair, T.; Zenit, R.; Zenit, R.; Spelt, P. D. M.</p> <p>1999-01-01</p> <p>In this work the gas volume fraction and the root-mean-squared fluid velocity are measured in buoyancy driven shear flows of <span class="hlt">bubble</span> suspensions in a tall, inclined, rectangular channel. The experiments are performed under conditions where We << 1a nd Re >> 1, for which comparisons are made with kinetic theory and numerical simulations. Here Re = gamma(a(exp 2)/nu is the Reynolds number and We = rho(gamma(exp 2))a(exp 3)/sigma is the Weber number; gamma is the shear rate, a is the <span class="hlt">bubble</span> radius, nu is the kinematic viscosity of the liquid, rho is the density of the liquid, and sigma is the surface tension of the gas/liquid interface. Kang et al. calculated the <span class="hlt">bubble</span> phase pressure and velocity variance of sheared <span class="hlt">bubble</span> suspensions under conditions where the <span class="hlt">bubbles</span> are spherical and the liquid phase velocity field can be approximated using potential flow theory, i.e. We= 0 and Re >> 1. Such conditions can be achieved in an experiment using gas <span class="hlt">bubbles</span>, with a radius of O(0.5mm), in water. The theory requires that there be no average relative motion of the gas and liquid phases, hence the motivation for an experimental program in microgravity. The necessity of performing preliminary, Earth based experiments, however, requires performing experiments where the gas phase <span class="hlt">rises</span> in the liquid, which significantly complicates the comparison of experiments with theory. Rather than comparing experimental results with theory for a uniform, homogeneous shear flow, experiments can be compared directly with solutions of the averaged equations of motion for <span class="hlt">bubble</span> suspensions. This requires accounting for the significant lift force acting on the gas phase when the <span class="hlt">bubbles</span> <span class="hlt">rise</span> parallel to the average velocity of the sheared suspension. Shear flows can be produced in which the <span class="hlt">bubble</span> phase pressure gradient, arising from shear induced collisions amongst the <span class="hlt">bubbles</span>, balances a body force (centrifugal or gravitational) on the gas phase. A steady, non-uniform gas volume fraction</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040142377','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040142377"><span>MOBI: Microgravity Observations of <span class="hlt">Bubble</span> Interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koch, Donald L.; Sangani, Ashok</p> <p>2004-01-01</p> <p>One of the greatest uncertainties affecting the design of multiphase flow technologies for space exploration is the spatial distribution of phases that will arise in microgravity or reduced gravity. On Earth, buoyancy-driven motion predominates whereas the shearing of the <span class="hlt">bubble</span> suspension controls its behavior in microgravity. We are conducting a series of ground-based experiments and a flight experiment spanning the full range of ratios of buoyancy to shear. These include: (1) <span class="hlt">bubbles</span> <span class="hlt">rising</span> in a quiescent liquid in a vertical channel; (2) weak shear flow induced by slightly inclining the channel; (3) moderate shear flow in a terrestrial vertical pipe flow; and (4) shearing of a <span class="hlt">bubble</span> suspension in a cylindrical Couette cell in microgravity. We consider nearly monodisperse suspensions of 1 to 1.8 mm diameter <span class="hlt">bubbles</span> in aqueous electrolyte solutions. The liquid velocity disturbance produced by <span class="hlt">bubbles</span> in this size range can often be described using an inviscid analysis. Electrolytic solutions lead to hydrophilic repulsion forces that stabilize the <span class="hlt">bubble</span> suspension without causing Marangoni stresses. We will discuss the mechanisms that control the flow behavior and phase distribution in the ground-based experiments and speculate on the factors that may influence the suspension flow and <span class="hlt">bubble</span> volume fraction distribution in the flight experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.3428B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.3428B"><span><span class="hlt">Bubble</span> video experiments in the marine waters off Panarea Island (Italy): real-world data for modelling CO2 <span class="hlt">bubble</span> dissolution and evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaubien, Stan; De Vittor, Cinzia; McGinnis, Dan; Bigi, Sabina; Comici, Cinzia; Ingrosso, Gianmarco; Lombardi, Salvatore; Ruggiero, Livio</p> <p>2014-05-01</p> <p>Carbon capture and storage is expected to provide an important, short-term contribution to mitigate global climate change due to anthropogenic emissions of CO2. Offshore reservoirs are particularly favourable, however concerns exist regarding the potential for CO2 leakage into the water column (with possible ecosystem impacts) and the atmosphere. Although laboratory experiments and modelling can examine these issues, the study of natural systems can provide a more complete and realistic understanding. For this reason the natural CO2 emission site off the coast of Panarea Island (Italy) was chosen for study within the EC-funded ECO2 project. The present paper discusses the results of field experiments conducted at this site to better understand the fate of CO2 gas <span class="hlt">bubbles</span> as they <span class="hlt">rise</span> through the water column, and to use this real-world data as input to test the predictive capabilities of a <span class="hlt">bubble</span> model. Experiments were conducted using a 1m wide x 1m deep x 3m tall, hollow-tube structure equipped with a vertical guide on the front face and a dark, graduated cloth for contrast and depth reference on the back. A Plexiglas box was filled with the naturally emitted gas and fixed on the seafloor inside the structure. Tubes exit the top of the box to make <span class="hlt">bubbles</span> of different diameters, while valves on each tube control <span class="hlt">bubble</span> release rate. <span class="hlt">Bubble</span> <span class="hlt">rise</span> velocity was measured by tracking each <span class="hlt">bubble</span> with a HD video camera mounted in the guide and calculating values over 20 cm intervals. <span class="hlt">Bubble</span> diameter was measured by filming the <span class="hlt">bubbles</span> as they collide with a graduated Plexiglas sheet deployed horizontally at the measurement height. <span class="hlt">Bubble</span> gas was collected at different heights using a funnel and analysed in the laboratory for CO2, O2+Ar, N2, and CH4. Water parameters were measured by performing a CTD cast beside the structure and collecting water samples at four depths using a Niskin bottle; samples were analysed in the laboratory for all carbonate system species, DO</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890010133','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890010133"><span>A computationally efficient modelling of laminar separation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dini, Paolo; Maughmer, Mark D.</p> <p>1989-01-01</p> <p>The goal is to accurately predict the <span class="hlt">characteristics</span> of the laminar separation <span class="hlt">bubble</span> and its effects on airfoil performance. Toward this end, a computational model of the separation <span class="hlt">bubble</span> was developed and incorporated into the Eppler and Somers airfoil design and analysis program. Thus far, the focus of the research was limited to the development of a model which can accurately predict situations in which the interaction between the <span class="hlt">bubble</span> and the inviscid velocity distribution is weak, the so-called short <span class="hlt">bubble</span>. A summary of the research performed in the past nine months is presented. The <span class="hlt">bubble</span> model in its present form is then described. Lastly, the performance of this model in predicting <span class="hlt">bubble</span> <span class="hlt">characteristics</span> is shown for a few cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JThSc..22..242L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JThSc..22..242L"><span>Interaction mechanism of double <span class="hlt">bubbles</span> in hydrodynamic cavitation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Fengchao; Cai, Jun; Huai, Xiulan; Liu, Bin</p> <p>2013-06-01</p> <p><span class="hlt">Bubble-bubble</span> interaction is an important factor in cavitation <span class="hlt">bubble</span> dynamics. In this paper, the dynamic behaviors of double cavitation <span class="hlt">bubbles</span> driven by varying pressure field downstream of an orifice plate in hydrodynamic cavitation reactor are examined. The <span class="hlt">bubble-bubble</span> interaction between two <span class="hlt">bubbles</span> with different radii is considered. We have shown the different dynamic behaviors between double cavitation <span class="hlt">bubbles</span> and a single <span class="hlt">bubble</span> by solving two coupling nonlinear equations using the Runge-Kutta fourth order method with adaptive step size control. The simulation results indicate that, when considering the role of the neighbor smaller <span class="hlt">bubble</span>, the oscillation of the bigger <span class="hlt">bubble</span> gradually exhibits a lag in comparison with the single-<span class="hlt">bubble</span> case, and the extent of the lag becomes much more obvious as time goes by. This phenomenon is more easily observed with the increase of the initial radius of the smaller <span class="hlt">bubble</span>. In comparison with the single-<span class="hlt">bubble</span> case, the oscillation of the bigger <span class="hlt">bubble</span> is enhanced by the neighbor smaller <span class="hlt">bubble</span>. Especially, the pressure pulse of the bigger <span class="hlt">bubble</span> <span class="hlt">rises</span> intensely when the sizes of two <span class="hlt">bubbles</span> approach, and a series of peak values for different initial radii are acquired when the initial radius ratio of two <span class="hlt">bubbles</span> is in the range of 0.9˜1.0. Although the increase of the center distance between two <span class="hlt">bubbles</span> can weaken the mutual interaction, it has no significant influence on the enhancement trend. On the one hand, the interaction between two <span class="hlt">bubbles</span> with different radii can suppress the growth of the smaller <span class="hlt">bubble</span>; on the other hand, it also can enhance the growth of the bigger one at the same time. The significant enhancement effect due to the interaction of multi-<span class="hlt">bubbles</span> should be paid more attention because it can be used to reinforce the cavitation intensity for various potential applications in future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMOS44A..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMOS44A..01W"><span>Quantification of Methane Gas Flux and <span class="hlt">Bubble</span> Fate on the Eastern Siberian Arctic Shelf Utilizing Calibrated Split-beam Echosounder Data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weidner, E. F.; Mayer, L. A.; Weber, T. C.; Jerram, K.; Jakobsson, M.; Chernykh, D.; Ananiev, R.; Mohammad, R.; Semiletov, I. P.</p> <p>2016-12-01</p> <p>On the Eastern Siberian Arctic Shelf (ESAS) subsea permafrost, shallow gas hydrates, and trapped free gas hold an estimated 1400 Gt of methane. Recent observations of methane <span class="hlt">bubble</span> plumes and high concentrations of dissolved methane in the water column indicate methane release via ebullition. Methane gas released from the shallow ESAS (<50 m average depth) has high potential to be transported to the atmosphere. To directly and quantitatively address the magnitude of methane flux and the fate of <span class="hlt">rising</span> <span class="hlt">bubbles</span> in the ESAS, methane seeps were mapped with a broadband split-beam echosounder as part of the Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions program (SWERUS-C3). Acoustic measurements were made over a broad range of frequencies (16 to 29 kHz). The broad bandwidth provided excellent discrimination of individual targets in the water column, allowing for the identification of single <span class="hlt">bubbles</span>. Absolute <span class="hlt">bubble</span> target strength values were determined by compensating apparent target strength measurements for beam pattern effects via standard calibration techniques. The <span class="hlt">bubble</span> size distribution of seeps with individual <span class="hlt">bubble</span> signatures was determined by exploiting <span class="hlt">bubble</span> target strength models over the broad range of frequencies. For denser seeps, with potential higher methane flux, <span class="hlt">bubble</span> size distribution was determined via extrapolation from seeps in similar geomorphological settings. By coupling <span class="hlt">bubble</span> size distributions with <span class="hlt">rise</span> velocity measurements, which are made possible by split-beam target tracking, methane gas flux can be estimated. Of the 56 identified seeps in the SWERUS data set, individual <span class="hlt">bubbles</span> scatterers were identified in more than half (31) of the seeps. Preliminary <span class="hlt">bubble</span> size distribution results indicate <span class="hlt">bubble</span> radii range from 0.75 to 3.0 mm, with relatively constant <span class="hlt">bubble</span> size distribution throughout the water column. Initial <span class="hlt">rise</span> velocity observations indicate <span class="hlt">bubble</span> <span class="hlt">rise</span> velocity increases with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..104..134W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..104..134W"><span>A deep-sea, high-speed, stereoscopic imaging system for in situ measurement of natural seep <span class="hlt">bubble</span> and droplet <span class="hlt">characteristics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Binbin; Socolofsky, Scott A.</p> <p>2015-10-01</p> <p>Development, testing, and application of a deep-sea, high-speed, stereoscopic imaging system are presented. The new system is designed for field-ready deployment, focusing on measurement of the <span class="hlt">characteristics</span> of natural seep <span class="hlt">bubbles</span> and droplets with high-speed and high-resolution image capture. The stereo view configuration allows precise evaluation of the physical scale of the moving particles in image pairs. Two laboratory validation experiments (a continuous <span class="hlt">bubble</span> chain and an airstone <span class="hlt">bubble</span> plume) were carried out to test the calibration procedure, performance of image processing and <span class="hlt">bubble</span> matching algorithms, three-dimensional viewing, and estimation of <span class="hlt">bubble</span> size distribution and volumetric flow rate. The results showed that the stereo view was able to improve the individual <span class="hlt">bubble</span> size measurement over the single-camera view by up to 90% in the two validation cases, with the single-camera being biased toward overestimation of the flow rate. We also present the first application of this imaging system in a study of natural gas seeps in the Gulf of Mexico. The high-speed images reveal the rigidity of the transparent <span class="hlt">bubble</span> interface, indicating the presence of clathrate hydrate skins on the natural gas <span class="hlt">bubbles</span> near the source (lowest measurement 1.3 m above the vent). We estimated the dominant <span class="hlt">bubble</span> size at the seep site Sleeping Dragon in Mississippi Canyon block 118 to be in the range of 2-4 mm and the volumetric flow rate to be 0.2-0.3 L/min during our measurements from 17 to 21 July 2014.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4738301','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4738301"><span>Steady State Vapor <span class="hlt">Bubble</span> in Pool Boiling</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C.; Maroo, Shalabh C.</p> <p>2016-01-01</p> <p>Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The <span class="hlt">bubble</span> ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial <span class="hlt">characteristics</span> of a single <span class="hlt">bubble</span>. Here, we create a steady-state vapor <span class="hlt">bubble</span> that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the <span class="hlt">bubble</span> allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor <span class="hlt">bubble</span> in degassed water shows a completely wetted <span class="hlt">bubble</span> base with the microlayer, and the <span class="hlt">bubble</span> does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental <span class="hlt">characteristics</span> of a stable vapor <span class="hlt">bubble</span> will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics. PMID:26837464</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Shrink&pg=3&id=EJ951386','ERIC'); return false;" href="https://eric.ed.gov/?q=Shrink&pg=3&id=EJ951386"><span>Affirmative Discrimination and the <span class="hlt">Bubble</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Clegg, Roger</p> <p>2011-01-01</p> <p>In this essay, the author discusses how affirmative action contributed to an unnatural <span class="hlt">rise</span> in enrollments in college. In considering the higher education <span class="hlt">bubble</span>, he makes the case that as the opposition to preferences continues to build, the momentum of this trend will only increase as funding shrinks. He offers some tentative answers to a series…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3561622','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3561622"><span><span class="hlt">Bubbling</span> behavior of a fluidized bed of fine particles caused by vibration-induced air inflow</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi</p> <p>2013-01-01</p> <p>We demonstrate that a vibration-induced air inflow can cause vigorous <span class="hlt">bubbling</span> in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of <span class="hlt">bubbles</span> that <span class="hlt">rise</span> and eventually burst at the top surface of the powder bed. A negative pressure is created below the <span class="hlt">rising</span> <span class="hlt">bubbles</span>. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously <span class="hlt">bubbling</span> fluidized bed that does not require the use of an external air supply system. PMID:23378921</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23378921','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23378921"><span><span class="hlt">Bubbling</span> behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi</p> <p>2013-01-01</p> <p>We demonstrate that a vibration-induced air inflow can cause vigorous <span class="hlt">bubbling</span> in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of <span class="hlt">bubbles</span> that <span class="hlt">rise</span> and eventually burst at the top surface of the powder bed. A negative pressure is created below the <span class="hlt">rising</span> <span class="hlt">bubbles</span>. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously <span class="hlt">bubbling</span> fluidized bed that does not require the use of an external air supply system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ExFl...59...52I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ExFl...59...52I"><span>Effects of free-stream turbulence intensity on transition in a laminar separation <span class="hlt">bubble</span> formed over an airfoil</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Istvan, Mark S.; Yarusevych, Serhiy</p> <p>2018-03-01</p> <p>The laminar-to-turbulent transition process in a laminar separation <span class="hlt">bubble</span> formed over a NACA 0018 airfoil is investigated experimentally. All experiments are performed for an angle of attack of 4°, chord Reynolds numbers of 80,000 and 125,000, and free-stream turbulence intensities between 0.06 and 1.99%. The results show that increasing the level of free-stream turbulence intensity leads to a decrease in separation <span class="hlt">bubble</span> length, attributed to a downstream shift in mean separation and an upstream shift in mean reattachment, the later ascribed to an upstream shift in mean transition. Maximum spatial amplification rates of disturbances in the separated shear layer decrease with increasing free-stream turbulence intensity, implying that the larger initial amplitudes of disturbances are solely responsible for the upstream shift in mean transition and as a result mean reattachment. At the baseline level of turbulence intensity, coherent structures forming in the aft portion of the <span class="hlt">bubble</span> are characterized by strong spanwise coherence at formation, and undergo spanwise deformations leading to localized breakup in the vicinity of mean reattachment. As the level of free-stream turbulence intensity is increased, the spanwise coherence of the shear layer rollers is reduced, and spanwise undulations in the vortex filaments start to take place at the mean location of roll-up. At the highest level of turbulence intensity investigated, streamwise streaks originating in the boundary layer upstream of the separation <span class="hlt">bubble</span> are observed within the <span class="hlt">bubble</span>. These streaks signify an onset of bypass transition upstream of the separation <span class="hlt">bubble</span>, which gives <span class="hlt">rise</span> to a highly three-dimensional shear layer roll-up. A quantitative analysis of the associated changes in salient <span class="hlt">characteristics</span> of the coherent structures is presented, connecting the effect of elevated free-stream turbulence intensity on the time-averaged and dynamic <span class="hlt">characteristics</span> of the separation <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDH12005L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDH12005L"><span><span class="hlt">Bubble</span> dynamics and <span class="hlt">bubble</span>-induced turbulence of a single-<span class="hlt">bubble</span> chain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Joohyoung; Park, Hyungmin</p> <p>2016-11-01</p> <p>In the present study, the <span class="hlt">bubble</span> dynamics and liquid-phase turbulence induced by a chain of <span class="hlt">bubbles</span> injected from a single nozzle have been experimentally investigated. Using a high-speed two-phase particle image velociemtry, measurements on the <span class="hlt">bubbles</span> and liquid-phase velocity field are conducted in a transparent tank filled with water, while varying the <span class="hlt">bubble</span> release frequency from 0.1 to 35 Hz. The tested <span class="hlt">bubble</span> size ranges between 2.0-3.2 mm, and the corresponding <span class="hlt">bubble</span> Reynolds number is 590-1100, indicating that it belongs to the regime of path instability. As the release frequency increases, it is found that the global shape of <span class="hlt">bubble</span> dispersion can be classified into two regimes: from asymmetric (regular) to axisymmetric (irregular). In particular, at higher frequency, the wake vortices of leading <span class="hlt">bubbles</span> cause an irregular behaviour of the following <span class="hlt">bubble</span>. For the liquid phase, it is found that a specific trend on the <span class="hlt">bubble</span>-induced turbulence appears in a strong relation to the above <span class="hlt">bubble</span> dynamics. Considering this, we try to provide a theoretical model to estimate the liquid-phase turbulence induced by a chain of <span class="hlt">bubbles</span>. Supported by a Grant funded by Samsung Electronics, Korea.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhDT........93D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhDT........93D"><span>Single <span class="hlt">bubble</span> sonoluminescence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dan, Manas</p> <p></p> <p> just after the initial collapse. The pressure amplitudes of the main AE spike are much weaker below the sonoluminescing regime. The amplitude of the principal AE spike in the sonoluminescing regime is about 1.2 atm at 7.2 mm from the <span class="hlt">bubble</span>. The <span class="hlt">rise</span> time as well as the FWHM of the principal spikes and after bounces in three different regimes of <span class="hlt">bubble</span> motion has been reported. A light scattering experiment has been carried out to study the <span class="hlt">bubble</span> dynamics. An extremely strong correlation between the results of light scattering and those of AE has been found.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001101&hterms=black+lives+matter&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dblack%2Blives%2Bmatter','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001101&hterms=black+lives+matter&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dblack%2Blives%2Bmatter"><span>FEASTING BLACK HOLE BLOWS <span class="hlt">BUBBLES</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>A monstrous black hole's rude table manners include blowing huge <span class="hlt">bubbles</span> of hot gas into space. At least, that's the gustatory practice followed by the supermassive black hole residing in the hub of the nearby galaxy NGC 4438. Known as a peculiar galaxy because of its unusual shape, NGC 4438 is in the Virgo Cluster, 50 million light-years from Earth. These NASA Hubble Space Telescope images of the galaxy's central region clearly show one of the <span class="hlt">bubbles</span> <span class="hlt">rising</span> from a dark band of dust. The other <span class="hlt">bubble</span>, emanating from below the dust band, is barely visible, appearing as dim red blobs in the close-up picture of the galaxy's hub (the colorful picture at right). The background image represents a wider view of the galaxy, with the central region defined by the white box. These extremely hot <span class="hlt">bubbles</span> are caused by the black hole's voracious eating habits. The eating machine is engorging itself with a banquet of material swirling around it in an accretion disk (the white region below the bright <span class="hlt">bubble</span>). Some of this material is spewed from the disk in opposite directions. Acting like high-powered garden hoses, these twin jets of matter sweep out material in their paths. The jets eventually slam into a wall of dense, slow-moving gas, which is traveling at less than 223,000 mph (360,000 kph). The collision produces the glowing material. The <span class="hlt">bubbles</span> will continue to expand and will eventually dissipate. Compared with the life of the galaxy, this <span class="hlt">bubble</span>-blowing phase is a short-lived event. The <span class="hlt">bubble</span> is much brighter on one side of the galaxy's center because the jet smashed into a denser amount of gas. The brighter <span class="hlt">bubble</span> is 800 light-years tall and 800 light-years across. The observations are being presented June 5 at the American Astronomical Society meeting in Rochester, N.Y. Both pictures were taken March 24, 1999 with the Wide Field and Planetary Camera 2. False colors were used to enhance the details of the <span class="hlt">bubbles</span>. The red regions in the picture denote the hot gas</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21041109','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21041109"><span>Characterization of an acoustic cavitation <span class="hlt">bubble</span> structure at 230 kHz.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thiemann, Andrea; Nowak, Till; Mettin, Robert; Holsteyns, Frank; Lippert, Alexander</p> <p>2011-03-01</p> <p>A generic <span class="hlt">bubble</span> structure in a 230 kHz ultrasonic field is observed in a partly developed standing wave field in water. It is characterized by high-speed imaging, sonoluminescence recordings, and surface cleaning tests. The structure has two distinct <span class="hlt">bubble</span> populations. Bigger <span class="hlt">bubbles</span> (much larger than linear resonance size) group on rings in planes parallel to the transducer surface, apparently in locations of driving pressure minima. They slowly <span class="hlt">rise</span> in a jittering, but synchronous way, and they can have smaller satellite <span class="hlt">bubbles</span>, thus resembling the arrays of <span class="hlt">bubbles</span> observed by Miller [D. Miller, Stable arrays of resonant <span class="hlt">bubbles</span> in a 1-MHz standing-wave acoustic field, J. Acoust. Soc. Am. 62 (1977) 12]. Smaller <span class="hlt">bubbles</span> (below and near linear resonance size) show a fast "streamer" motion perpendicular to and away from the transducer surface. While the bigger <span class="hlt">bubbles</span> do not emit light, the smaller <span class="hlt">bubbles</span> in the streamers show sonoluminescence when they pass the planes of high driving pressure. Both <span class="hlt">bubble</span> populations exhibit cleaning potential with respect to micro-particles attached to a glass substrate. The respective mechanisms of particle removal, though, might be different. Copyright © 2010 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhyA..382..235R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhyA..382..235R"><span>On the maximum drawdown during speculative <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rotundo, Giulia; Navarra, Mauro</p> <p>2007-08-01</p> <p>A taxonomy of large financial crashes proposed in the literature locates the burst of speculative <span class="hlt">bubbles</span> due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the bulk of drawdown price movement distribution. This paper goes on deeper in the analysis providing a further characterization of the <span class="hlt">rising</span> part of such selected <span class="hlt">bubbles</span> through the examination of drawdown and maximum drawdown movement of indices prices. The analysis of drawdown duration is also performed and it is the core of the risk measure estimated here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AnGeo..36...91B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AnGeo..36...91B"><span><span class="hlt">Characteristics</span> of equatorial plasma <span class="hlt">bubbles</span> observed by TEC map based on ground-based GNSS receivers over South America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barros, Diego; Takahashi, Hisao; Wrasse, Cristiano M.; Figueiredo, Cosme Alexandre O. B.</p> <p>2018-01-01</p> <p>A ground-based network of GNSS receivers has been used to monitor equatorial plasma <span class="hlt">bubbles</span> (EPBs) by mapping the total electron content (TEC map). The large coverage of the TEC map allowed us to monitor several EPBs simultaneously and get <span class="hlt">characteristics</span> of the dynamics, extension and longitudinal distributions of the EPBs from the onset time until their disappearance. These <span class="hlt">characteristics</span> were obtained by using TEC map analysis and the keogram technique. TEC map databases analyzed were for the period between November 2012 and January 2016. The zonal drift velocities of the EPBs showed a clear latitudinal gradient varying from 123 m s-1 at the Equator to 65 m s-1 for 35° S latitude. Consequently, observed EPBs are inclined against the geomagnetic field lines. Both zonal drift velocity and the inclination of the EPBs were compared to the thermospheric neutral wind, which showed good agreement. Moreover, the large two-dimensional coverage of TEC maps allowed us to study periodic EPBs with a wide longitudinal distance. The averaged values observed for the inter-<span class="hlt">bubble</span> distances also presented a clear latitudinal gradient varying from 920 km at the Equator to 640 km at 30° S. The latitudinal gradient in the inter-<span class="hlt">bubble</span> distances seems to be related to the difference in the zonal drift velocity of the EPB from the Equator to middle latitudes and to the difference in the westward movement of the terminator. On several occasions, the distances reached more than 2000 km. Inter-<span class="hlt">bubble</span> distances greater than 1000 km have not been reported in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29408118','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29408118"><span>Estimation of structural film viscosity based on the <span class="hlt">bubble</span> <span class="hlt">rise</span> method in a nanofluid.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cho, Heon Ki; Nikolov, Alex D; Wasan, Darsh T</p> <p>2018-04-15</p> <p>When a single <span class="hlt">bubble</span> moves at a very low capillary number (10 -7 ) through a liquid with dispersed nanoparticles (nanofluid) inside a vertical tube/capillary, a film is formed between the <span class="hlt">bubble</span> surface and the tube wall and the nanoparticles self-layer inside the confined film. We measured the film thickness using reflected light interferometry. We calculated the film structural energy isotherm vs. the film thickness from the film-meniscus contact angle measurements using the reflected light interferometric method. Based on the experimental measurement of the film thickness and the calculated values of the film structural energy barrier, we estimated the structural film viscosity vs. the film thickness using the Frenkel approach. Because of the nanoparticle film self-layering phenomenon, we observed a gradual increase in the film viscosity with the decreasing film thickness. However, we observed a significant increase in the film viscosity accompanied by a step-wise decrease in the <span class="hlt">bubble</span> velocity when the film thickness decreased from 3 to 2 particle layers due to the structural transition in the film. Copyright © 2018 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001129&hterms=Hawthorn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DHawthorn','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001129&hterms=Hawthorn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DHawthorn"><span>BURST OF STAR FORMATION DRIVES <span class="hlt">BUBBLE</span> IN GALAXY'S CORE</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>These NASA Hubble Space Telescope snapshots reveal dramatic activities within the core of the galaxy NGC 3079, where a lumpy <span class="hlt">bubble</span> of hot gas is <span class="hlt">rising</span> from a cauldron of glowing matter. The picture at left shows the <span class="hlt">bubble</span> in the center of the galaxy's disk. The structure is more than 3,000 light-years wide and <span class="hlt">rises</span> 3,500 light-years above the galaxy's disk. The smaller photo at right is a close-up view of the <span class="hlt">bubble</span>. Astronomers suspect that the <span class="hlt">bubble</span> is being blown by 'winds' (high-speed streams of particles) released during a burst of star formation. Gaseous filaments at the top of the <span class="hlt">bubble</span> are whirling around in a vortex and are being expelled into space. Eventually, this gas will rain down upon the galaxy's disk where it may collide with gas clouds, compress them, and form a new generation of stars. The two white dots just above the <span class="hlt">bubble</span> are probably stars in the galaxy. The close-up reveals that the <span class="hlt">bubble</span>'s surface is lumpy, consisting of four columns of gaseous filaments that tower above the galaxy's disk. The filaments disperse at a height of 2,000 light-years. Each filament is about 75 light-years wide. Velocity measurements taken by the Canada-France-Hawaii Telescope in Hawaii show that the gaseous filaments are ascending at more than 4 million miles an hour (6 million kilometers an hour). According to theoretical models, the <span class="hlt">bubble</span> formed when ongoing winds from hot stars mixed with small <span class="hlt">bubbles</span> of very hot gas from supernova explosions. Observations of the core's structure by radio telescopes indicate that those processes are still active. The models suggest that this outflow began about a million years ago. They occur about every 10 million years. Eventually, the hot stars will die, and the <span class="hlt">bubble</span>'s energy source will fade away. Astronomers have seen evidence of previous outbursts from radio and X-ray observations. Those studies show rings of dust and gas and long plumes of material, all of which are larger than the <span class="hlt">bubble</span>. NGC 3079 is 50</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21032489-moduli-vacuum-bubbles-produced-evaporating-black-holes','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21032489-moduli-vacuum-bubbles-produced-evaporating-black-holes"><span>Moduli vacuum <span class="hlt">bubbles</span> produced by evaporating black holes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Morris, J. R.</p> <p>2007-10-15</p> <p>We consider a model with a toroidally compactified extra dimension giving <span class="hlt">rise</span> to a temperature-dependent 4D effective potential with one-loop contributions due to the Casimir effect, along with a 5D cosmological constant. The forms of the effective potential at low and high temperatures indicate a possibility for the formation of a domain wall <span class="hlt">bubble</span>, formed by the modulus scalar field, surrounding an evaporating black hole. This is viewed as an example of a recently proposed black hole vacuum <span class="hlt">bubble</span> arising from matter-sourced moduli fields in the vicinity of an evaporating black hole [D. Green, E. Silverstein, and D. Starr, Phys.more » Rev. D 74, 024004 (2006)]. The black hole <span class="hlt">bubble</span> can be highly opaque to lower-energy particles and photons, and thereby entrap them within. For high-temperature black holes, there may also be a symmetry-breaking black hole <span class="hlt">bubble</span> of false vacuum of the type previously conjectured by Moss [I. G. Moss, Phys. Rev. D 32, 1333 (1985)], tending to reflect low-energy particles from its wall. A double <span class="hlt">bubble</span> composed of these two different types of <span class="hlt">bubble</span> may form around the black hole, altering the hole's emission spectrum that reaches outside observers. Smaller mass black holes that have already evaporated away could have left vacuum <span class="hlt">bubbles</span> behind that contribute to the dark matter.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008APS..DFD.AH004L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008APS..DFD.AH004L"><span>Asymmetric <span class="hlt">bubble</span> collapse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lai, Lipeng; Turitsyn, Konstantin S.; Zhang, Wendy W.</p> <p>2008-11-01</p> <p>Recent studies reveal that an inertial implosion, analogous to the collapse of a large cavity in water, governs how a submerged air <span class="hlt">bubble</span> disconnects from a nozzle. For the <span class="hlt">bubble</span>, slight asymmetries in the initial neck shape give <span class="hlt">rise</span> to vibrations that grow pronounced over time. These results motivate our study of the final stage of asymmetric cavity collapse. We are particularly interested in the generic situation where the initial condition is sufficiently well-focused that a cavity can implode inwards energetically. Yet, because the initial condition is not perfectly symmetric, the implosion fails to condense all the energy. We consider cavity shapes in the slender-body limit, for which the collapse dynamics is quasi two-dimensional. In this limit, each cross-section of the cavity evolves as if it were a distorted void immersed in an inviscid and irrotational fluid. Simulations of a circular void distorted by an elongation-compression vibrational mode reveal that a variety of outcomes are possible in the 2D problem. Opposing sides of the void surface can curve inwards and contact smoothly in a finite amount of time. Depending on the phase of the vibration excited, the contact can be either north-south or east-west. Phase values that lie in the transition zone from one orientation to the other give <span class="hlt">rise</span> to final shapes with large lengthscale separation. We show also that the final outcome varies non-monotonically with the initial amplitude of the vibrational mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010012148&hterms=surfactants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsurfactants','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010012148&hterms=surfactants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsurfactants"><span>Remobilizing the Interfaces of Thermocapillary Driven <span class="hlt">Bubbles</span> Retarded by the Adsorption of a Surfactant Impurity on the <span class="hlt">Bubble</span> Surface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Palaparthi, Ravi; Maldarelli, Charles; Papageorgiou, Dimitri; Singh, Bhim S. (Technical Monitor)</p> <p>2000-01-01</p> <p> concentrations than the impurity, it adsorbs to the <span class="hlt">bubble</span> much faster than the impurity when the <span class="hlt">bubble</span> is formed, and thereby prevents the impurity from adsorbing onto the surface. In addition the rapid kinetic exchange and high bulk concentration maintain a saturated surface with a uniform surface concentrations. This prevents retarding surface tension gradients and keeps the velocity high. In our first report last year, we detailed experimental results which verified the theory of remobilization in ground based experiments in which the steady velocity of <span class="hlt">rising</span> <span class="hlt">bubbles</span> was measured in a continuous phase consisting of a glycerol/water mixture containing a polyethylene glycol surfactant C12E6 (CH3(CH2)11(OCH2CH2)6OH). In our report this year, we detail our efforts to describe theoretically the remobilization observed. We construct a model in which a <span class="hlt">bubble</span> <span class="hlt">rises</span> steadily by buoyancy in a continuous (Newtonian) viscous fluid containing surfactant with a uniform far field bulk concentration. We account for the effects of inertia as well as viscosity in the flow in the continuous phase caused by the <span class="hlt">bubble</span> motion (order one Reynolds number), and we assume that the <span class="hlt">bubble</span> shape remains spherical (viscous and inertial forces are smaller than capillary forces, i e. small Weber and capillary numbers). The surfactant distribution is calculated by solving the mass transfer equations including convection and diffusion in the bulk, and finite kinetic exchange the bulk and the surface. Convective effects dominate diffusive mass transfer in the bulk of the liquid (high Peclet numbers) except in a thin boundary layer near the surface. A finite volume method is used to numerically solve the hydrodynamic and mass transfer equations on a staggered grid which accounts specifically for the thin boundary layer. We present the results of the nondimensional drag as a function of the bulk concentration of surfactant for different rates of kinetic exchange, from which we develop criteria for the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhyA..391..180Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhyA..391..180Y"><span>Leverage <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Wanfeng; Woodard, Ryan; Sornette, Didier</p> <p>2012-01-01</p> <p>Leverage is strongly related to liquidity in a market and lack of liquidity is considered a cause and/or consequence of the recent financial crisis. A repurchase agreement is a financial instrument where a security is sold simultaneously with an agreement to buy it back at a later date. Repurchase agreement (repo) market size is a very important element in calculating the overall leverage in a financial market. Therefore, studying the behavior of repo market size can help to understand a process that can contribute to the birth of a financial crisis. We hypothesize that herding behavior among large investors led to massive over-leveraging through the use of repos, resulting in a <span class="hlt">bubble</span> (built up over the previous years) and subsequent crash in this market in early 2008. We use the Johansen-Ledoit-Sornette (JLS) model of rational expectation <span class="hlt">bubbles</span> and behavioral finance to study the dynamics of the repo market that led to the crash. The JLS model qualifies a <span class="hlt">bubble</span> by the presence of <span class="hlt">characteristic</span> patterns in the price dynamics, called log-periodic power law (LPPL) behavior. We show that there was significant LPPL behavior in the market before that crash and that the predicted range of times predicted by the model for the end of the <span class="hlt">bubble</span> is consistent with the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407724','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407724"><span>A multi-functional <span class="hlt">bubble</span>-based microfluidic system</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Khoshmanesh, Khashayar; Almansouri, Abdullah; Albloushi, Hamad; Yi, Pyshar; Soffe, Rebecca; Kalantar-zadeh, Kourosh</p> <p>2015-01-01</p> <p>Recently, the <span class="hlt">bubble</span>-based systems have offered a new paradigm in microfluidics. Gas <span class="hlt">bubbles</span> are highly flexible, controllable and barely mix with liquids, and thus can be used for the creation of reconfigurable microfluidic systems. In this work, a hydrodynamically actuated <span class="hlt">bubble</span>-based microfluidic system is introduced. This system enables the precise movement of air <span class="hlt">bubbles</span> via axillary feeder channels to alter the geometry of the main channel and consequently the flow <span class="hlt">characteristics</span> of the system. Mixing of neighbouring streams is demonstrated by oscillating the <span class="hlt">bubble</span> at desired displacements and frequencies. Flow control is achieved by pushing the <span class="hlt">bubble</span> to partially or fully close the main channel. Patterning of suspended particles is also demonstrated by creating a large <span class="hlt">bubble</span> along the sidewalls. Rigorous analytical and numerical calculations are presented to describe the operation of the system. The examples presented in this paper highlight the versatility of the developed <span class="hlt">bubble</span>-based actuator for a variety of applications; thus providing a vision that can be expanded for future highly reconfigurable microfluidics. PMID:25906043</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JOUC...16..223L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JOUC...16..223L"><span>Numerical simulation of <span class="hlt">bubble</span> plumes and an analysis of their seismic attributes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Canping; Gou, Limin; You, Jiachun</p> <p>2017-04-01</p> <p>To study the <span class="hlt">bubble</span> plume's seismic response <span class="hlt">characteristics</span>, the model of a plume water body has been built in this article using the <span class="hlt">bubble</span>-contained medium acoustic velocity model and the stochastic medium theory based on an analysis of both the acoustic <span class="hlt">characteristics</span> of a <span class="hlt">bubble</span>-contained water body and the actual features of a plume. The finite difference method is used for forward modelling, and the single-shot seismic record exhibits the <span class="hlt">characteristics</span> of a scattered wave field generated by a plume. A meaningful conclusion is obtained by extracting seismic attributes from the pre-stack shot gather record of a plume. The values of the amplitude-related seismic attributes increase greatly as the <span class="hlt">bubble</span> content goes up, and changes in <span class="hlt">bubble</span> radius will not cause seismic attributes to change, which is primarily observed because the <span class="hlt">bubble</span> content has a strong impact on the plume's acoustic velocity, while the <span class="hlt">bubble</span> radius has a weak impact on the acoustic velocity. The above conclusion provides a theoretical reference for identifying hydrate plumes using seismic methods and contributes to further study on hydrate decomposition and migration, as well as on distribution of the methane <span class="hlt">bubble</span> in seawater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1368176-void-fraction-bubble-size-interfacial-area-measurements-co-current-downflow-bubble-column-reactor-microbubble-dispersion','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1368176-void-fraction-bubble-size-interfacial-area-measurements-co-current-downflow-bubble-column-reactor-microbubble-dispersion"><span>Void fraction, <span class="hlt">bubble</span> size and interfacial area measurements in co-current downflow <span class="hlt">bubble</span> column reactor with microbubble dispersion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Hernandez-Alvarado, Freddy; Kalaga, Dinesh V.; Turney, Damon; ...</p> <p>2017-05-06</p> <p>Micro-<span class="hlt">bubbles</span> dispersed in <span class="hlt">bubble</span> column reactors have received great interest in recent years, due to their small size, stability, high gas-liquid interfacial area concentrations and longer residence times. The high gas-liquid interfacial area concentrations lead to high mass transfer rates compared to conventional <span class="hlt">bubble</span> column reactors. In the present work, experiments have been performed in a down-flow <span class="hlt">bubble</span> column reactor with micro-<span class="hlt">bubbles</span> generated and dispersed by a novel mechanism to determine the gas-liquid interfacial area concentrations by measuring the void fraction and <span class="hlt">bubble</span> size distributions. Gamma-ray densitometry has been employed to determine the axial and radial distributions of void fractionmore » and a high speed camera equipped with a borescope is used to measure the axial and radial variations of <span class="hlt">bubble</span> sizes. Also, the effects of superficial gas and liquid velocities on the two-phase flow <span class="hlt">characteristics</span> have been investigated. Further, reconstruction techniques of the radial void fraction profiles from the gamma densitometry's chordal measurements are discussed and compared for a <span class="hlt">bubble</span> column reactor with dispersed micro-<span class="hlt">bubbles</span>. The results demonstrate that the new <span class="hlt">bubble</span> generation technique offers high interfacial area concentrations (1,000 to 4,500 m 2/m 3) with sub-millimeter <span class="hlt">bubbles</span> (500 to 900 µm) and high overall void fractions (10% – 60%) in comparison with previous <span class="hlt">bubble</span> column reactor designs. The void fraction data was analyzed using slip velocity model and empirical correlation has been proposed to predict the Sauter mean <span class="hlt">bubble</span> diameter.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1368176','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1368176"><span>Void fraction, <span class="hlt">bubble</span> size and interfacial area measurements in co-current downflow <span class="hlt">bubble</span> column reactor with microbubble dispersion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hernandez-Alvarado, Freddy; Kalaga, Dinesh V.; Turney, Damon</p> <p></p> <p>Micro-<span class="hlt">bubbles</span> dispersed in <span class="hlt">bubble</span> column reactors have received great interest in recent years, due to their small size, stability, high gas-liquid interfacial area concentrations and longer residence times. The high gas-liquid interfacial area concentrations lead to high mass transfer rates compared to conventional <span class="hlt">bubble</span> column reactors. In the present work, experiments have been performed in a down-flow <span class="hlt">bubble</span> column reactor with micro-<span class="hlt">bubbles</span> generated and dispersed by a novel mechanism to determine the gas-liquid interfacial area concentrations by measuring the void fraction and <span class="hlt">bubble</span> size distributions. Gamma-ray densitometry has been employed to determine the axial and radial distributions of void fractionmore » and a high speed camera equipped with a borescope is used to measure the axial and radial variations of <span class="hlt">bubble</span> sizes. Also, the effects of superficial gas and liquid velocities on the two-phase flow <span class="hlt">characteristics</span> have been investigated. Further, reconstruction techniques of the radial void fraction profiles from the gamma densitometry's chordal measurements are discussed and compared for a <span class="hlt">bubble</span> column reactor with dispersed micro-<span class="hlt">bubbles</span>. The results demonstrate that the new <span class="hlt">bubble</span> generation technique offers high interfacial area concentrations (1,000 to 4,500 m 2/m 3) with sub-millimeter <span class="hlt">bubbles</span> (500 to 900 µm) and high overall void fractions (10% – 60%) in comparison with previous <span class="hlt">bubble</span> column reactor designs. The void fraction data was analyzed using slip velocity model and empirical correlation has been proposed to predict the Sauter mean <span class="hlt">bubble</span> diameter.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MeScT..29g5206F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MeScT..29g5206F"><span>3D <span class="hlt">bubble</span> reconstruction using multiple cameras and space carving method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, Yucheng; Liu, Yang</p> <p>2018-07-01</p> <p>An accurate measurement of <span class="hlt">bubble</span> shape and size has a significant value in understanding the behavior of <span class="hlt">bubbles</span> that exist in many engineering applications. Past studies usually use one or two cameras to estimate <span class="hlt">bubble</span> volume, surface area, among other parameters. The 3D <span class="hlt">bubble</span> shape and rotation angle are generally not available in these studies. To overcome this challenge and obtain more detailed information of individual <span class="hlt">bubbles</span>, a 3D imaging system consisting of four high-speed cameras is developed in this paper, and the space carving method is used to reconstruct the 3D <span class="hlt">bubble</span> shape based on the recorded high-speed images from different view angles. The proposed method can reconstruct the <span class="hlt">bubble</span> surface with minimal assumptions. A benchmarking test is performed in a 3 cm × 1 cm rectangular channel with stagnant water. The results show that the newly proposed method can measure the <span class="hlt">bubble</span> volume with an error of less than 2% compared with the syringe reading. The conventional two-camera system has an error around 10%. The one-camera system has an error greater than 25%. The visualization of a 3D <span class="hlt">bubble</span> <span class="hlt">rising</span> demonstrates the wall influence on <span class="hlt">bubble</span> rotation angle and aspect ratio. This also explains the large error that exists in the single camera measurement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFD.E4003S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFD.E4003S"><span>On the Physics of Fizziness: How <span class="hlt">Bubble</span> Bursting Controls Droplets Ejection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seon, Thomas; Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe</p> <p>2014-11-01</p> <p>Either in a champagne glass or at the oceanic scales, the tiny <span class="hlt">bubbles</span> <span class="hlt">rising</span> at the surface burst in ejecting myriads of droplets. Focusing on the <span class="hlt">bubble</span> bursting jet, prelude for these aerosols, we propose a simple scaling for the jet velocity, we unravel experimentally the intricate roles of <span class="hlt">bubble</span> shape, capillary waves and liquid properties, and we demonstrate that droplets ejection can be tuned by changing the liquid properties. In particular, as capillary waves are shown to always evolve into a self-similar collapsing cavity, faster and smaller droplets can be produced by sheltering this collapse from remnant ripples using damping action of viscosity. These results pave the road to the characterization and control of the bursting <span class="hlt">bubble</span> aerosols. Applications to champagne aroma diffusion will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...35a2020K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...35a2020K"><span>Gas transfer in a <span class="hlt">bubbly</span> wake flow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karn, A.; Gulliver, J. S.; Monson, G. M.; Ellis, C.; Arndt, R. E. A.; Hong, J.</p> <p>2016-05-01</p> <p>The present work reports simultaneous <span class="hlt">bubble</span> size and gas transfer measurements in a <span class="hlt">bubbly</span> wake flow of a hydrofoil, designed to be similar to a hydroturbine blade. <span class="hlt">Bubble</span> size was measured by a shadow imaging technique and found to have a Sauter mean diameter of 0.9 mm for a reference case. A lower gas flow rate, greater liquid velocities, and a larger angle of attack all resulted in an increased number of small size <span class="hlt">bubbles</span> and a reduced weighted mean <span class="hlt">bubble</span> size. <span class="hlt">Bubble</span>-water gas transfer is measured by the disturbed equilibrium technique. The gas transfer model of Azbel (1981) is utilized to characterize the liquid film coefficient for gas transfer, with one scaling coefficient to reflect the fact that <span class="hlt">characteristic</span> turbulent velocity is replaced by cross-sectional mean velocity. The coefficient was found to stay constant at a particular hydrofoil configuration while it varied within a narrow range of 0.52-0.60 for different gas/water flow conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AAS...23123705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AAS...23123705K"><span>A Statistical Study of the Southern Fermi <span class="hlt">Bubble</span> in UV Absorption Spectra</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karim, Md. Tanveer; Fox, Andrew; Jenkins, Edward; Bordoloi, Rongmon; Wakker, Bart; Savage, Blair D.; Lockman, Felix; Crawford, Steve; Bland-Hawthorn, Joss; Jorgenson, Regina A.</p> <p>2018-01-01</p> <p>The Fermi <span class="hlt">Bubbles</span> are two giant lobes of plasma situated at the center of the Milky Way, extending 55° above and below the Galactic Midplane. Although the <span class="hlt">Bubbles</span> have been widely studied in multiple wavelengths, few studies have been done in UV absorption. Here we present a statistical study of the Southern Fermi <span class="hlt">Bubble</span> using 17 QSO sightlines — 6 inside the <span class="hlt">Bubble</span>, 11 outside — using UV absorption spectra from the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS). We searched for high-velocity clouds (HVCs) in 11 metal lines from ions of Aluminium, Carbon and Silicon. We detected HVCs in 83% of the sightlines inside the <span class="hlt">Bubble</span> and 64% outside the <span class="hlt">Bubble</span>, showing an enhancement in the covering fraction of HVCs in the Southern <span class="hlt">Bubble</span> region. We also observed a decrease in vLSR of the HVCs as a function of the galactic latitude, consistent with a scenario where the identified HVCs trace the Galactic nuclear outflow, as sightlines closer to the central engine are expected to show a higher velocity. Combined with previous studies, our analysis indicates that the Southern Fermi <span class="hlt">Bubble</span> is a dynamic environment giving <span class="hlt">rise</span> to complex absorption features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26406633','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26406633"><span>Monte Carlo simulation of spectral reflectance and BRDF of the <span class="hlt">bubble</span> layer in the upper ocean.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Lanxin; Wang, Fuqiang; Wang, Chengan; Wang, Chengchao; Tan, Jianyu</p> <p>2015-09-21</p> <p>The presence of <span class="hlt">bubbles</span> can significantly change the radiative properties of seawater and these changes will affect remote sensing and underwater target detection. In this work, the spectral reflectance and bidirectional reflectance <span class="hlt">characteristics</span> of the <span class="hlt">bubble</span> layer in the upper ocean are investigated using the Monte Carlo method. The Hall-Novarini (HN) <span class="hlt">bubble</span> population model, which considers the effect of wind speed and depth on the <span class="hlt">bubble</span> size distribution, is used. The scattering coefficients and the scattering phase functions of <span class="hlt">bubbles</span> in seawater are calculated using Mie theory, and the inherent optical properties of seawater for wavelengths between 300 nm and 800 nm are related to chlorophyll concentration (Chl). The effects of <span class="hlt">bubble</span> coating, Chl, and <span class="hlt">bubble</span> number density on the spectral reflectance of the <span class="hlt">bubble</span> layer are studied. The bidirectional reflectance distribution function (BRDF) of the <span class="hlt">bubble</span> layer for both normal and oblique incidence is also investigated. The results show that <span class="hlt">bubble</span> populations in clear waters under high wind speed conditions significantly influence the reflection <span class="hlt">characteristics</span> of the <span class="hlt">bubble</span> layer. Furthermore, the contribution of <span class="hlt">bubble</span> populations to the reflection <span class="hlt">characteristics</span> is mainly due to the strong backscattering of <span class="hlt">bubbles</span> that are coated with an organic film.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNH53B2004K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNH53B2004K"><span>Increasing of Gas <span class="hlt">Bubbling</span> at Wariishi Flowing Spring, Central Japan, before and after the 2014 Ontake Volcano Eruption</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kimata, F.; Tasaka, S.; Asai, Y.</p> <p>2016-12-01</p> <p>Wariishi Spa is locating at Atotsugawa active fault, and it is an flowing spring from the 850m depth by the bore hole. The spring is coming from the rain fall through the geological boundary. Discharge was measured 100L/minute by manual every week in 1977. In 1990, measurement system was updated to 1Hz by electromagnetic flowmeter system. Co-seismic discharge <span class="hlt">rises</span> are measured for about 100 examples of the earthquake occurrence in around area. The discharge <span class="hlt">rise</span> is decreasing asymptotic convergence with time. In 2011 Tohoku Earthquake, the discharge of spring is a <span class="hlt">rise</span> of 30 L/minutes, and it took 1 and half year to return to 20 L/minute. Ontake Volcano is one of the active volcanoes in same mountain range, but it is located about 50 km south from the Wariishi spa. There are three active volcanoes between Wariishi Spa and Ontake Volcano. The volcano was erupted in a phreatic explosion on September 27, 2014. There is no observation of the discharge change at the eruption in the hot spring. There are other hot spring systems in Wariishi spa. The spa has a periodic spring with one to two-hour frequencies. The periodic frequencies are depended on the discharge volume. Therefore, at the co-seismic discharge <span class="hlt">rise</span>, the shortenings of periodic frequencies are observed. Hence, the mechanism of main discharge and periodic spring is located at the depth of 850 m. Based on discussion on time series of discharge spa, there are observed many pulsed noises between the periodic springs. The noises are caused by gas <span class="hlt">bubbling</span> from the precise examinations. It is suggested that gas <span class="hlt">bubbling</span> is different mechanism with periodic spring, because no effects on the periodic spring frequency. <span class="hlt">Bubbling</span> is sourced from more deep than 850 m. Gas <span class="hlt">bubbling</span> was observed about 50 times between the periodic spa around the Ontake volcano eruption. There is no report on such gas <span class="hlt">bubbling</span> <span class="hlt">rise</span> since 2012. Discussed above, it is suggested some changes of strain field at central Japan, especially in</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24571670','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24571670"><span>How many <span class="hlt">bubbles</span> in your glass of <span class="hlt">bubbly</span>?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liger-Belair, Gérard</p> <p>2014-03-20</p> <p>The issue about how many carbon dioxide <span class="hlt">bubbles</span> are likely to nucleate in a glass of champagne (or <span class="hlt">bubbly</span>) is of concern for sommeliers, wine journalists, experienced tasters, and any open minded physical chemist wondering about complex phenomena at play in a glass of <span class="hlt">bubbly</span>. The whole number of <span class="hlt">bubbles</span> likely to form in a single glass is the result of the fine interplay between dissolved CO2, tiny gas pockets trapped within particles acting as <span class="hlt">bubble</span> nucleation sites, and ascending <span class="hlt">bubble</span> dynamics. Based on theoretical models combining ascending <span class="hlt">bubble</span> dynamics and mass transfer equations, the falsely naı̈ve question of how many <span class="hlt">bubbles</span> are likely to form per glass is discussed in the present work. A theoretical relationship is derived, which provides the whole number of <span class="hlt">bubbles</span> likely to form per glass, depending on various parameters of both the wine and the glass itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AnRFM..49..221P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AnRFM..49..221P"><span>Vapor <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prosperetti, Andrea</p> <p>2017-01-01</p> <p>This article reviews the fundamental physics of vapor <span class="hlt">bubbles</span> in liquids. Work on <span class="hlt">bubble</span> growth and condensation for stationary and translating <span class="hlt">bubbles</span> is summarized and the differences with <span class="hlt">bubbles</span> containing a permanent gas stressed. In particular, it is shown that the natural frequency of a vapor <span class="hlt">bubble</span> is proportional not to the inverse radius, as for a gas <span class="hlt">bubble</span>, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the <span class="hlt">bubble</span> with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of pressure waves in a vaporous <span class="hlt">bubbly</span> liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and vapor <span class="hlt">bubbles</span> in an immiscible liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4388830','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4388830"><span><span class="hlt">Bubble</span>-Induced Cave Collapse</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Girihagama, Lakshika; Nof, Doron; Hancock, Cathrine</p> <p>2015-01-01</p> <p>Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned “natural” instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers <span class="hlt">bubbles</span> <span class="hlt">rising</span> to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar <span class="hlt">bubble</span> dynamics, fluid dynamics of <span class="hlt">bubble</span>-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a “collapse”. We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the <span class="hlt">bubbles</span> were produced using a syringe located at the cave floor. PMID:25849088</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25849088','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25849088"><span><span class="hlt">Bubble</span>-induced cave collapse.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Girihagama, Lakshika; Nof, Doron; Hancock, Cathrine</p> <p>2015-01-01</p> <p>Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned "natural" instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers <span class="hlt">bubbles</span> <span class="hlt">rising</span> to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar <span class="hlt">bubble</span> dynamics, fluid dynamics of <span class="hlt">bubble</span>-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a "collapse". We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the <span class="hlt">bubbles</span> were produced using a syringe located at the cave floor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.A6003B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.A6003B"><span>Size of the top jet drop produced by <span class="hlt">bubble</span> bursting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berny, Alexis; Deike, Luc; Popinet, Stéphane; Seon, Thomas</p> <p>2017-11-01</p> <p>When a <span class="hlt">bubble</span> is located on a liquid-air interface, it eventually bursts. First, the <span class="hlt">bubble</span> cap shatters and produces film drops. Then, the cavity collapses, a tiny liquid jet <span class="hlt">rises</span> and, depending on <span class="hlt">bubble</span> radius and liquid parameters, it can eventually break-up and release the so-called jet drops. We perform numerical simulations, using the free software basilisk, to determine and discuss the regime of existence and the size of the first liquid jet droplets. We first validate the numerical scheme by comparing our results with recent experimental data. We then extend our numerical study to a wider range of control parameters in order to enrich our knowledge of the jet drops production. Finally, we show and interpret our results using a scaling law approach and basic physical arguments. This allows us to untangle the intricate roles of viscosity, gravity, and surface tension in the end pinching of the <span class="hlt">bubble</span> bursting jet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.739a2058W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.739a2058W"><span>Generation of Submicron <span class="hlt">Bubbles</span> using Venturi Tube Method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wiraputra, I. G. P. A. E.; Edikresnha, D.; Munir, M. M.; Khairurrijal</p> <p>2016-08-01</p> <p>In this experiment, submicron <span class="hlt">bubbles</span> that have diameters less than 1 millimeter were generated by mixing water and gas by hydrodynamic cavitation method. The water was forced to pass through a venturi tube in which the speed of the water will increase in the narrow section, the throat, of the venturi. When the speed of water increased, the pressure would drop at the throat of the venturi causing the outside air to be absorbed via the gas inlet. The gas was then trapped inside the water producing <span class="hlt">bubbles</span>. The effects of several physical parameters on the <span class="hlt">characteristics</span> of the <span class="hlt">bubbles</span> will be discussed thoroughly in this paper. It was found that larger amount of gas pressure during compression will increase the production rate of <span class="hlt">bubbles</span> and increase the density of <span class="hlt">bubble</span> within water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhRvL..98x4501R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhRvL..98x4501R"><span>Lifetime of <span class="hlt">Bubble</span> Rafts: Cooperativity and Avalanches</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ritacco, Hernán; Kiefer, Flavien; Langevin, Dominique</p> <p>2007-06-01</p> <p>We have studied the collapse of pseudo-bi-dimensional foams. These foams are made of uniformly sized soap <span class="hlt">bubbles</span> packed in an hexagonal lattice sitting at the top of a liquid surface. The collapse process follows the sequence: (1) rupture of a first <span class="hlt">bubble</span>, driven by thermal fluctuations and (2) a cascade of bursting <span class="hlt">bubbles</span>. We present a simple numerical model which captures the main <span class="hlt">characteristics</span> of the dynamics of foam collapse. We show that in a certain range of viscosities of the foaming solutions, the size distribution of the avalanches follows power laws as in self-organized criticality processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17677967','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17677967"><span>Lifetime of <span class="hlt">bubble</span> rafts: cooperativity and avalanches.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ritacco, Hernán; Kiefer, Flavien; Langevin, Dominique</p> <p>2007-06-15</p> <p>We have studied the collapse of pseudo-bi-dimensional foams. These foams are made of uniformly sized soap <span class="hlt">bubbles</span> packed in an hexagonal lattice sitting at the top of a liquid surface. The collapse process follows the sequence: (1) rupture of a first <span class="hlt">bubble</span>, driven by thermal fluctuations and (2) a cascade of bursting <span class="hlt">bubbles</span>. We present a simple numerical model which captures the main <span class="hlt">characteristics</span> of the dynamics of foam collapse. We show that in a certain range of viscosities of the foaming solutions, the size distribution of the avalanches follows power laws as in self-organized criticality processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020014638&hterms=mushrooms&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmushrooms','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020014638&hterms=mushrooms&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmushrooms"><span><span class="hlt">Bubble</span> Formation at a Submerged Orifice in Reduced Gravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Buyevich, Yu A.; Webbon, Bruce W.</p> <p>1994-01-01</p> <p>The dynamic regime of gas injection through a circular plate orifice into an ideally wetting liquid is considered, when successively detached <span class="hlt">bubbles</span> may be regarded as separate identities. In normal gravity and at relatively low gas flow rates, a growing <span class="hlt">bubble</span> is modeled as a spherical segment touching the orifice perimeter during the whole time of its evolution. If the flow rate exceeds a certain threshold value, another stage of the detachment process takes place in which an almost spherical gas envelope is connected with the orifice by a nearly cylindrical stem that lengthens as the <span class="hlt">bubble</span> <span class="hlt">rises</span> above the plate. The <span class="hlt">bubble</span> shape resembles then that of a mushroom and the upper envelope continues to grow until the gas supply through the stem is completely cut off. Such a stage is always present under conditions of sufficiently low gravity, irrespective of the flow rate. Two major reasons make for <span class="hlt">bubble</span> detachment: the buoyancy force and the force due to the momentum inflow into the <span class="hlt">bubble</span> with the injected gas. The former force dominates the process at normal gravity whereas the second one plays a key role under negligible gravity conditions. It is precisely this fundamental factor that conditions the drastic influence on <span class="hlt">bubble</span> growth and detachment that changes in gravity are able to cause. The frequency of <span class="hlt">bubble</span> formation is proportional to and the volume of detached <span class="hlt">bubbles</span> is independent of the gas flow rate in sufficiently low gravity, while at normal and moderately reduced gravity conditions the first variable slightly decreases and the second one almost linearly increases as the flow rate grows. Effects of other parameters, such as the orifice radius, gas and liquid densities, and surface tension are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880006567','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880006567"><span>A computationally efficient modelling of laminar separation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Maughmer, Mark D.</p> <p>1988-01-01</p> <p>The goal of this research is to accurately predict the <span class="hlt">characteristics</span> of the laminar separation <span class="hlt">bubble</span> and its effects on airfoil performance. To this end, a model of the <span class="hlt">bubble</span> is under development and will be incorporated in the analysis section of the Eppler and Somers program. As a first step in this direction, an existing <span class="hlt">bubble</span> model was inserted into the program. It was decided to address the problem of the short <span class="hlt">bubble</span> before attempting the prediction of the long <span class="hlt">bubble</span>. In the second place, an integral boundary-layer method is believed more desirable than a finite difference approach. While these two methods achieve similar prediction accuracy, finite-difference methods tend to involve significantly longer computer run times than the integral methods. Finally, as the boundary-layer analysis in the Eppler and Somers program employs the momentum and kinetic energy integral equations, a short-<span class="hlt">bubble</span> model compatible with these equations is most preferable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.tmp.1212Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.tmp.1212Z"><span>Generation of Internal Waves by Buoyant <span class="hlt">Bubbles</span> in Galaxy Clusters and Heating of Intracluster Medium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Congyao; Churazov, Eugene; Schekochihin, Alexander A.</p> <p>2018-05-01</p> <p>Buoyant <span class="hlt">bubbles</span> of relativistic plasma in cluster cores plausibly play a key role in conveying the energy from a supermassive black hole to the intracluster medium (ICM) - the process known as radio-mode AGN feedback. Energy conservation guarantees that a <span class="hlt">bubble</span> loses most of its energy to the ICM after crossing several pressure scale heights. However, actual processes responsible for transferring the energy to the ICM are still being debated. One attractive possibility is the excitation of internal waves, which are trapped in the cluster's core and eventually dissipate. Here we show that a sufficient condition for efficient excitation of these waves in stratified cluster atmospheres is flattening of the <span class="hlt">bubbles</span> in the radial direction. In our numerical simulations, we model the <span class="hlt">bubbles</span> phenomenologically as rigid bodies buoyantly <span class="hlt">rising</span> in the stratified cluster atmosphere. We find that the terminal velocities of the flattened <span class="hlt">bubbles</span> are small enough so that the Froude number Fr ≲ 1. The effects of stratification make the dominant contribution to the total drag force balancing the buoyancy force. Clear signs of internal waves are seen in the simulations. These waves propagate horizontally and downwards from the <span class="hlt">rising</span> <span class="hlt">bubble</span>, spreading their energy over large volumes of the ICM. If our findings are scaled to the conditions of the Perseus cluster, the expected terminal velocity is ˜100 - 200 km s-1 near the cluster cores, which is in broad agreement with direct measurements by the Hitomi satellite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5524383','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5524383"><span>Numerical Analysis of the Influence of Low Frequency Vibration on <span class="hlt">Bubble</span> Growth</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Han, D.; Kedzierski, Mark A.</p> <p>2017-01-01</p> <p>Numerical simulation of <span class="hlt">bubble</span> growth during pool boiling under the influence of low frequency vibration was performed to understand the influence of common vibrations such as those induced by wind, highway transportation, and nearby mechanical devices on the performance of thermal systems that rely on boiling. The simulations were done for saturated R123 boiling at 277.6 K with a 15 K wall superheat. The numerical volume-of-fluid method (fixed grid) was used to define the liquid-vapor interface. The basic <span class="hlt">bubble</span> growth <span class="hlt">characteristics</span> including the <span class="hlt">bubble</span> departure diameter and the <span class="hlt">bubble</span> departure time were determined as a function of the <span class="hlt">bubble</span> contact angle (20°–80°), the vibration displacement (10 µm–50 µm), the vibration frequency (5 Hz–25 Hz), and the initial vibration direction (positive or negative). The <span class="hlt">bubble</span> parameters were shown to be strongly dependent on the <span class="hlt">bubble</span> contact angle at the surface. For example, both the <span class="hlt">bubble</span> departure diameter and the <span class="hlt">bubble</span> departure time increased with the contact angle. At the same vibration frequency and the initial vibration direction, the <span class="hlt">bubble</span> departure diameter and the <span class="hlt">bubble</span> departure time both decreased with increasing vibration displacement. In addition, the vibration frequency had a greater effect on the <span class="hlt">bubble</span> growth <span class="hlt">characteristics</span> than did the vibration displacement. The vibration frequency effect was strongly influenced by the initial vibration direction. The pressure contour, the volume fraction of vapor phase, the temperature profile, and the velocity vector were investigated to understand these dynamic <span class="hlt">bubble</span> behaviors. The limitation of the computational fluid dynamics approach was also described. PMID:28747812</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS21B1698P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS21B1698P"><span>Analysis of <span class="hlt">bubble</span> plume spacing produced by regular breaking waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Phaksopa, J.; Haller, M. C.</p> <p>2012-12-01</p> <p>The breaking wave process in the ocean is a significant mechanism for energy dissipation, splash, and entrainment of air. The relationship between breaking waves and <span class="hlt">bubble</span> plume <span class="hlt">characteristics</span> is still a mystery because of the complexity of the breaking wave mechanism. This study takes a unique approach to quantitatively analyze <span class="hlt">bubble</span> plumes produced by regular breaking waves. Various previous studies have investigated the formation and the <span class="hlt">characteristics</span> of <span class="hlt">bubble</span> plumes using either field observations, laboratory experiments, or numerical modeling However, in most observational work the plume <span class="hlt">characteristics</span> have been studied from the underneath the water surface. In addition, though numerical simulations are able to include much of the important physics, the computational costs are high and <span class="hlt">bubble</span> plume events are only simulated for short times. Hence, <span class="hlt">bubble</span> plume evolution and generation throughout the surf zone is not yet computationally feasible. In the present work we take a unique approach to analyzing <span class="hlt">bubble</span> plumes. These data may be of use for model/data comparisons as numerical simulations become more tractable. The remotely sensed video data from freshwater breaking waves in the OSU Large Wave Flume (Catalan and Haller, 2008) are analyzed. The data set contains six different regular wave conditions and the video intensity data are used to estimate the spacing of plume events (wavenumber spectrum), to calculate the spectral width (i.e. the range of plume spacing), and to relate these with the wave conditions. The video intensity data capture the evolution of the wave passage over a fixed bed arranged in a bar-trough morphology. Bright regions represent the moving path or trajectory coincident with <span class="hlt">bubble</span> plume of each wave. It also shows the <span class="hlt">bubble</span> foam were generated and released from wave crest shown in the form of <span class="hlt">bubble</span> tails with almost regular spacing for each wave. The <span class="hlt">bubble</span> tails show that most <span class="hlt">bubbles</span> did not move along with wave. For the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhPl...25e3103F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhPl...25e3103F"><span>Electron self-injection in the donut <span class="hlt">bubble</span> wakefield</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Firouzjaei, Ali Shekari; Shokri, Babak</p> <p>2018-05-01</p> <p>We investigate electron self-injection in a donut <span class="hlt">bubble</span> wakefield driven by a Laguerre-Gauss laser pulse. The present work discusses the electron capture by modeling the analytical donut <span class="hlt">bubble</span> field. We discuss the self-injection of the electrons from plasma for various initial conditions and then compare the results. We show that the donut <span class="hlt">bubble</span> can trap plasma electrons forming a hollow beam. We present the phase spaces and longitudinal momentum evolution for the trapped electrons in the <span class="hlt">bubble</span> and discuss their <span class="hlt">characteristic</span> behaviors and stability. It will be shown that the electrons self-injected in the front are ideal for applications in which a good stability and low energy spread are essential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11402044H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11402044H"><span>CFD analysis of the two-phase <span class="hlt">bubbly</span> flow <span class="hlt">characteristics</span> in helically coiled rectangular and circular tube heat exchangers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hussain, Alamin; Fsadni, Andrew M.</p> <p>2016-03-01</p> <p>Due to their ease of manufacture, high heat transfer efficiency and compact design, helically coiled heat exchangers are increasingly being adopted in a number of industries. The higher heat transfer efficiency over straight pipes is due to the secondary flow that develops as a result of the centrifugal force. In spite of the widespread use of helically coiled heat exchangers, and the presence of <span class="hlt">bubbly</span> two-phase flow in a number of systems, very few studies have investigated the resultant flow <span class="hlt">characteristics</span>. This paper will therefore present the results of CFD simulations for the two-phase <span class="hlt">bubbly</span> flow in helically coiled heat exchangers as a function of the volumetric void fraction and the tube cross-section design. The CFD results are compared to the scarce flow visualisation experimental results available in the open literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005APS..DFD.BD003F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005APS..DFD.BD003F"><span><span class="hlt">Bubble</span> breakup phenomena in a venturi tube</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujiwara, Akiko</p> <p>2005-11-01</p> <p>Microbubble has distinguished <span class="hlt">characteristics</span> of large surface area to unit volume and small buoyancy, and it has advantages in many engineering fields. Recently microbubble generators with low energy and high performance are required to wide applications. In the present study, we propose one new effective technique to generate tiny <span class="hlt">bubbles</span> with less than 200 μm diameter utilizing venturi tube under high void fraction condition. The objective of the present study is to elucidate the mechanism of <span class="hlt">bubble</span> breakup phenomena in the venturi tube and to clarify the effects of parameters which are necessary to realize an optimum system experimentally. Experiment was conducted with void fraction of 4% and variation of liquid velocity from 9 to 26 m/s at the throat. Under low velocity condition, <span class="hlt">bubbles</span> which were observed with a high speed camera parted gradually in a wide region. On the contrary under high velocity condition, <span class="hlt">bubbles</span> expanded after passing through the throat and shrank rapidly. Since the speed of sound in gas-liquid system is extremely lower than that of single-phase flow, the <span class="hlt">bubble</span> breakup phenomenon in the venturi tube is explained as the supersonic flow in a Laval nozzle. By rapid pressure recovery in diverging area, expanding <span class="hlt">bubbles</span> collapse violently. The tiny <span class="hlt">bubbles</span> are generated due to the surface instability of shrinking <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020041256&hterms=swimming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dswimming','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020041256&hterms=swimming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dswimming"><span>Ring <span class="hlt">Bubbles</span> of Dolphins</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shariff, Karim; Marten, Ken; Psarakos, Suchi; White, Don J.; Merriam, Marshal (Technical Monitor)</p> <p>1996-01-01</p> <p>The article discusses how dolphins create and play with three types of air-filled vortices. The underlying physics is discussed. Photographs and sketches illustrating the dolphin's actions and physics are presented. The dolphins engage in this behavior on their own initiative without food reward. These behaviors are done repeatedly and with singleminded effort. The first type is the ejection of <span class="hlt">bubbles</span> which, after some practice on the part of the dolphin, turn into toroidal vortex ring <span class="hlt">bubbles</span> by the mechanism of baroclinic torque. These <span class="hlt">bubbles</span> grow in radius and become thinner as they <span class="hlt">rise</span> vertically to the surface. One dolphin would blow two in succession and guide them to fuse into one. Physicists call this a vortex reconnection. In the second type, the dolphins first create an invisible vortex ring in the water by swimming on their side and waving their tail fin (also called flukes) vigorously. This vortex ring travels horizontally in the water. The dolphin then turns around, finds the vortex and injects a stream of air into it from its blowhole. The air "fills-out" the core of the vortex ring. Often, the dolphin would knock-off a smaller ring <span class="hlt">bubble</span> from the larger ring (this also involves vortex reconnection) and steer the smaller ring around the tank. One other dolphin employed a few other techniques for planting air into the fluke vortex. One technique included standing vertically in the water with tail-up, head-down and tail piercing the free surface. As the fluke is waved to create the vortex ring, air is entrained from above the surface. Another technique was gulping air in the mouth, diving down, releasing air <span class="hlt">bubbles</span> from the mouth and curling them into a ring when they rose to the level of the fluke. In the third type, demonstrated by only one dolphin, the longitudinal vortex created by the dorsal fin on the back is used to produce 10-15 foot long helical <span class="hlt">bubbles</span>. In one technique she swims in a curved path. This creates a dorsal fin vortex since</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/accomplishments/glaser.html','SCIGOVWS'); return false;" href="http://www.osti.gov/accomplishments/glaser.html"><span>Donald Glaser, the <span class="hlt">Bubble</span> Chamber, and Elementary Particles</span></a></p> <p><a target="_blank" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Effects of Ionizing Radiation on the Formation of <span class="hlt">Bubbles</span> in Liquids <em>Physical</em> Review, Vol. 87, Issue 4 , 665, August 15, 1952 <span class="hlt">Characteristics</span> of <span class="hlt">Bubble</span> Chambers <em>Physical</em> Review, Vol. 97, Issue 2, 474-479 Chambers <em>Physical</em> Review, Vol. 102, Issue 6, 1653-1658, June 15, 1956 Methods of Particle Detection for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.3641C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.3641C"><span>Gas separation and <span class="hlt">bubble</span> behavior at a woven screen</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conrath, Michael; Dreyer, Michael E.</p> <p></p> <p> trapped <span class="hlt">bubble</span> volumes, liquid flow rates and flow-induced compression, ii) typical breakthrough of a trapped <span class="hlt">bubble</span> at <span class="hlt">rising</span> liquid flow rate and iii) steady gas supply in steady liquid flow. It shows that our model can explain the experimental observations. One of the interesting findings for the dynamic <span class="hlt">bubble</span> point is that hydraulic losses in the rest of the circuit will shift the breakthrough of gas to higher liquid flow rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3677508','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3677508"><span>Heat transport in <span class="hlt">bubbling</span> turbulent convection</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lakkaraju, Rajaram; Stevens, Richard J. A. M.; Oresta, Paolo; Verzicco, Roberto; Lohse, Detlef; Prosperetti, Andrea</p> <p>2013-01-01</p> <p>Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to numerous mechanisms, many of which are not understood in quantitative detail. An important component of the overall process is that the buoyancy of the <span class="hlt">bubble</span> compounds with that of the liquid to give <span class="hlt">rise</span> to a much-enhanced natural convection. In this article, we focus specifically on this enhancement and present a numerical study of the resulting two-phase Rayleigh–Bénard convection process in a cylindrical cell with a diameter equal to its height. We make no attempt to model other aspects of the boiling process such as <span class="hlt">bubble</span> nucleation and detachment. The cell base and top are held at temperatures above and below the boiling point of the liquid, respectively. By keeping this difference constant, we study the effect of the liquid superheat in a Rayleigh number range that, in the absence of boiling, would be between 2 × 106 and 5 × 109. We find a considerable enhancement of the heat transfer and study its dependence on the number of <span class="hlt">bubbles</span>, the degree of superheat of the hot cell bottom, and the Rayleigh number. The increased buoyancy provided by the <span class="hlt">bubbles</span> leads to more energetic hot plumes detaching from the cell bottom, and the strength of the circulation in the cell is significantly increased. Our results are in general agreement with recent experiments on boiling Rayleigh–Bénard convection. PMID:23696657</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23696657','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23696657"><span>Heat transport in <span class="hlt">bubbling</span> turbulent convection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lakkaraju, Rajaram; Stevens, Richard J A M; Oresta, Paolo; Verzicco, Roberto; Lohse, Detlef; Prosperetti, Andrea</p> <p>2013-06-04</p> <p>Boiling is an extremely effective way to promote heat transfer from a hot surface to a liquid due to numerous mechanisms, many of which are not understood in quantitative detail. An important component of the overall process is that the buoyancy of the <span class="hlt">bubble</span> compounds with that of the liquid to give <span class="hlt">rise</span> to a much-enhanced natural convection. In this article, we focus specifically on this enhancement and present a numerical study of the resulting two-phase Rayleigh-Bénard convection process in a cylindrical cell with a diameter equal to its height. We make no attempt to model other aspects of the boiling process such as <span class="hlt">bubble</span> nucleation and detachment. The cell base and top are held at temperatures above and below the boiling point of the liquid, respectively. By keeping this difference constant, we study the effect of the liquid superheat in a Rayleigh number range that, in the absence of boiling, would be between 2 × 10(6) and 5 × 10(9). We find a considerable enhancement of the heat transfer and study its dependence on the number of <span class="hlt">bubbles</span>, the degree of superheat of the hot cell bottom, and the Rayleigh number. The increased buoyancy provided by the <span class="hlt">bubbles</span> leads to more energetic hot plumes detaching from the cell bottom, and the strength of the circulation in the cell is significantly increased. Our results are in general agreement with recent experiments on boiling Rayleigh-Bénard convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhFl...16.1852P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhFl...16.1852P"><span><span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prosperetti, Andrea</p> <p>2004-06-01</p> <p>Vanitas vanitatum et omnia vanitas: <span class="hlt">bubbles</span> are emptiness, non-liquid, a tiny cloud shielding a mathematical singularity. Born from chance, a violent and brief life ending in the union with the (nearly) infinite. But a wealth of phenomena spring forth from this nothingness: underwater noise, sonoluminescence, boiling, and many others. Some recent results on a "blinking <span class="hlt">bubble</span>" micropump and vapor <span class="hlt">bubbles</span> in sound fields are outlined. The last section describes Leonardo da Vinci's observation of the non-rectlinear ascent of buoyant <span class="hlt">bubbles</span> and justifies the name Leonardo's paradox recently attributed to this phenomenon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F7009K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F7009K"><span>Freezing <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kingett, Christian; Ahmadi, Farzad; Nath, Saurabh; Boreyko, Jonathan</p> <p>2017-11-01</p> <p>The two-stage freezing process of a liquid droplet on a substrate is well known; however, how <span class="hlt">bubbles</span> freeze has not yet been studied. We first deposited <span class="hlt">bubbles</span> on a silicon substrate that was chilled at temperatures ranging from -10 °C to -40 °C, while the air was at room temperature. We observed that the freeze front moved very slowly up the <span class="hlt">bubble</span>, and in some cases, even came to a complete halt at a critical height. This slow freezing front propagation can be explained by the low thermal conductivity of the thin soap film, and can be observed more clearly when the <span class="hlt">bubble</span> size or the surface temperature is increased. This delayed freezing allows the frozen portion of the <span class="hlt">bubble</span> to cool the air within the <span class="hlt">bubble</span> while the top part is still liquid, which induces a vapor pressure mismatch that either collapses the top or causes the top to pop. In cases where the freeze front reaches the top of the <span class="hlt">bubble</span>, a portion of the top may melt and slowly refreeze; this can happen more than just once for a single <span class="hlt">bubble</span>. We also investigated freezing <span class="hlt">bubbles</span> inside of a freezer where the air was held at -20 °C. In this case, the <span class="hlt">bubbles</span> freeze quickly and the ice grows radially from nucleation sites instead of perpendicular to the surface, which provides a clear contrast with the conduction limited room temperature <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUOSHI54B1859P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUOSHI54B1859P"><span>In Situ Raman Spectroscopic Observations of Gas-Saturated <span class="hlt">Rising</span> Oil droplets: Simulation with Decane as an Oil-Equivalent Substitute</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peltzer, E. T.; Walz, P. M.; Brewer, P. G.</p> <p>2016-02-01</p> <p>Oil droplets <span class="hlt">rising</span> from the sea floor, whether from seeps or well leakage, contain very large quantities of dissolved gas that profoundly affects their density and critical oil-water interfacial <span class="hlt">characteristics</span>. The primary dissolved gas is methane which may be up to 30% of the molar volume. This can create a hydrate skin as the methane gas is shed from the oil as it <span class="hlt">rises</span> through the water column, thus decreasing in pressure and increasing in temperature, and steadily changing the <span class="hlt">rising</span> droplet buoyancy. We have explored this phenomenon by executing controlled ROV based experiments with a "<span class="hlt">bubble</span> cup" technique in which a small volume of gas saturated decane (saturated with pure methane, a mix of methane and nitrogen , or a mix of methane and CO2) is interrogated by laser Raman spectroscopy. The use of decane as an oil "substitute" is required since natural oil samples are highly fluorescent due to the presence of polycyclic aromatic hydrocarbons. We have devised Matlab techniques for extracting the spectroscopic dissolved methane signal from the thicket of decane peaks that surround it. We have directly observed the rate at which gases are lost from the "oil" per unit area at depths in the water column that are both within and outside the hydrate forming phase boundary. We have compared the behavior of both a non-hydrate forming dissolved gas (nitrogen) with CO2 where the hydrate phase boundary is at significantly shallower depth. The results indicate complex interfacial behavior and physical chemistry. We did not observe direct gas <span class="hlt">bubble</span> formation on the decane outer surface but did observe gas <span class="hlt">bubble</span> formation within the oil droplets as they rose through the water column. Because there are significant energy barriers for homogeneous <span class="hlt">bubble</span> formation within the decane phase, we took this as evidence of significant gas super-saturation within the oil droplet. The gas loss rates increased significantly in all cases when the hydrate phase boundary was crossed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Surfactants&pg=2&id=EJ633596','ERIC'); return false;" href="https://eric.ed.gov/?q=Surfactants&pg=2&id=EJ633596"><span><span class="hlt">Bubble</span>, <span class="hlt">Bubble</span>, Toil and Trouble.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Journal of Chemical Education, 2001</p> <p>2001-01-01</p> <p><span class="hlt">Bubbles</span> are a fun way to introduce the concepts of surface tension, intermolecular forces, and the use of surfactants. Presents two activities in which students add chemicals to liquid dishwashing detergent with water in order to create longer lasting <span class="hlt">bubbles</span>. (ASK)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDH36006T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDH36006T"><span>Distinguishing between microscale gaseous <span class="hlt">bubbles</span> and liquid drops</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tan, Beng Hau; An, Hongjie; Chan, Chon U.; Ohl, Claus-Dieter</p> <p>2015-11-01</p> <p>In recent years, there has been strong research interest in decorating surfaces with tiny <span class="hlt">bubbles</span> and drops due to their potential applications in reducing slippage in micro and nanofluidic devices. Both nanobubbles and nanodrops are typically nucleated by exchanging fluids over a suitable substrate. However, the nucleation experiments present many challenges, such as reproducibility and the possibility of contamination. The use of one-use plastic syringes and needle cannulas in nucleation experiments can introduce polymeric contamination. A contaminated experiment may nucleate <span class="hlt">bubbles</span>, drops or both. Moreover, it is surprisingly difficult to distinguish between <span class="hlt">bubbles</span> and drops under the usual atomic force microscopy or optical techniques. Here we present an experimental study comparing <span class="hlt">bubbles</span> and oil (PDMS) drops on an atomically smooth surface (HOPG). Instead of nucleating the objects via solvent exchange, we directly introduced <span class="hlt">bubbles</span> via electrolysis, and oil drops by injecting a dilute solution. Contrary to previous reports, we find that under careful AFM characterisation, liquid drops and gaseous <span class="hlt">bubbles</span> respond differently to a change in imaging force, and moreover present different <span class="hlt">characteristic</span> force curves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22088010','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22088010"><span><span class="hlt">Bubble</span> dynamics in a standing sound field: the <span class="hlt">bubble</span> habitat.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koch, P; Kurz, T; Parlitz, U; Lauterborn, W</p> <p>2011-11-01</p> <p><span class="hlt">Bubble</span> dynamics is investigated numerically with special emphasis on the static pressure and the positional stability of the <span class="hlt">bubble</span> in a standing sound field. The <span class="hlt">bubble</span> habitat, made up of not dissolving, positionally and spherically stable <span class="hlt">bubbles</span>, is calculated in the parameter space of the <span class="hlt">bubble</span> radius at rest and sound pressure amplitude for different sound field frequencies, static pressures, and gas concentrations of the liquid. The <span class="hlt">bubble</span> habitat grows with static pressure and shrinks with sound field frequency. The range of diffusionally stable <span class="hlt">bubble</span> oscillations, found at positive slopes of the habitat-diffusion border, can be increased substantially with static pressure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22088012','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22088012"><span>Optical nucleation of <span class="hlt">bubble</span> clouds in a high pressure spherical resonator.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderson, Phillip; Sampathkumar, A; Murray, Todd W; Gaitan, D Felipe; Glynn Holt, R</p> <p>2011-11-01</p> <p>An experimental setup for nucleating clouds of <span class="hlt">bubbles</span> in a high-pressure spherical resonator is described. Using nanosecond laser pulses and multiple phase gratings, <span class="hlt">bubble</span> clouds are optically nucleated in an acoustic field. Dynamics of the clouds are captured using a high-speed CCD camera. The images reveal cloud nucleation, growth, and collapse and the resulting emission of radially expanding shockwaves. These shockwaves are reflected at the interior surface of the resonator and then reconverge to the center of the resonator. As the shocks reconverge upon the center of the resonator, they renucleate and grow the <span class="hlt">bubble</span> cloud. This process is repeated over many acoustic cycles and with each successive shock reconvergence, the <span class="hlt">bubble</span> cloud becomes more organized and centralized so that subsequent collapses give <span class="hlt">rise</span> to stronger, better defined shockwaves. After many acoustic cycles individual <span class="hlt">bubbles</span> cannot be distinguished and the cloud is then referred to as a cluster. Sustainability of the process is ultimately limited by the detuning of the acoustic field inside the resonator. The nucleation parameter space is studied in terms of laser firing phase, laser energy, and acoustic power used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870036169&hterms=Glass+bubble&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGlass%2Bbubble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870036169&hterms=Glass+bubble&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGlass%2Bbubble"><span>Physical data measurements and mathematical modelling of simple gas <span class="hlt">bubble</span> experiments in glass melts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weinberg, Michael C.</p> <p>1986-01-01</p> <p>In this work consideration is given to the problem of the extraction of physical data information from gas <span class="hlt">bubble</span> dissolution and growth measurements. The discussion is limited to the analysis of the simplest experimental systems consisting of a single, one component gas <span class="hlt">bubble</span> in a glassmelt. It is observed that if the glassmelt is highly under- (super-) saturated, then surface tension effects may be ignored, simplifying the task of extracting gas diffusivity values from the measurements. If, in addition, the <span class="hlt">bubble</span> <span class="hlt">rise</span> velocity is very small (or very large) the ease of obtaining physical property data is enhanced. Illustrations are given for typical cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18163660','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18163660"><span><span class="hlt">Bubble</span> colloidal AFM probes formed from ultrasonically generated <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vakarelski, Ivan U; Lee, Judy; Dagastine, Raymond R; Chan, Derek Y C; Stevens, Geoffrey W; Grieser, Franz</p> <p>2008-02-05</p> <p>Here we introduce a simple and effective experimental approach to measuring the interaction forces between two small <span class="hlt">bubbles</span> (approximately 80-140 microm) in aqueous solution during controlled collisions on the scale of micrometers to nanometers. The colloidal probe technique using atomic force microscopy (AFM) was extended to measure interaction forces between a cantilever-attached <span class="hlt">bubble</span> and surface-attached <span class="hlt">bubbles</span> of various sizes. By using an ultrasonic source, we generated numerous small <span class="hlt">bubbles</span> on a mildly hydrophobic surface of a glass slide. A single <span class="hlt">bubble</span> picked up with a strongly hydrophobized V-shaped cantilever was used as the colloidal probe. Sample force measurements were used to evaluate the pure water <span class="hlt">bubble</span> cleanliness and the general consistency of the measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26016773','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26016773"><span><span class="hlt">Bubble</span> pump: scalable strategy for in-plane liquid routing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oskooei, Ali; Günther, Axel</p> <p>2015-07-07</p> <p>We present an on-chip liquid routing technique intended for application in well-based microfluidic systems that require long-term active pumping at low to medium flowrates. Our technique requires only one fluidic feature layer, one pneumatic control line and does not rely on flexible membranes and mechanical or moving parts. The presented <span class="hlt">bubble</span> pump is therefore compatible with both elastomeric and rigid substrate materials and the associated scalable manufacturing processes. Directed liquid flow was achieved in a microchannel by an in-series configuration of two previously described "<span class="hlt">bubble</span> gates", i.e., by gas-<span class="hlt">bubble</span> enabled miniature gate valves. Only one time-dependent pressure signal is required and initiates at the upstream (active) <span class="hlt">bubble</span> gate a reciprocating <span class="hlt">bubble</span> motion. Applied at the downstream (passive) gate a time-constant gas pressure level is applied. In its rest state, the passive gate remains closed and only temporarily opens while the liquid pressure <span class="hlt">rises</span> due to the active gate's reciprocating <span class="hlt">bubble</span> motion. We have designed, fabricated and consistently operated our <span class="hlt">bubble</span> pump with a variety of working liquids for >72 hours. Flow rates of 0-5.5 μl min(-1), were obtained and depended on the selected geometric dimensions, working fluids and actuation frequencies. The maximum operational pressure was 2.9 kPa-9.1 kPa and depended on the interfacial tension of the working fluids. Attainable flow rates compared favorably with those of available micropumps. We achieved flow rate enhancements of 30-100% by operating two <span class="hlt">bubble</span> pumps in tandem and demonstrated scalability of the concept in a multi-well format with 12 individually and uniformly perfused microchannels (variation in flow rate <7%). We envision the demonstrated concept to allow for the consistent on-chip delivery of a wide range of different liquids that may even include highly reactive or moisture sensitive solutions. The presented <span class="hlt">bubble</span> pump may provide active flow control for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.V53A1531G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.V53A1531G"><span>Magnetite Scavenging and the Buoyancy of <span class="hlt">Bubbles</span> in Magmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gualda, G. A.; Ghiorso, M. S.</p> <p>2005-12-01</p> <p>It is generally assumed that when eruptions are triggered, magmas are <span class="hlt">bubble</span>-free, and all the vesicularity observed in pumice is due to nucleation and growth during ascent. However, decompression experiments show that <span class="hlt">bubbles</span> tend to nucleate on magnetite crystals at relatively low supersaturation, and there is convincing evidence that an exsolved gas phase was present during much of the evolution of the Bishop magma. The fate of pre-eruptive <span class="hlt">bubbles</span> depends directly on their buoyancy, which can be strongly modified by the presence of crystals attached to the <span class="hlt">bubble</span>-melt interface. That crystals tend to attach to <span class="hlt">bubbles</span> is indicated by experiments and observations, and can be explained theoretically. Whether, however, crystals and <span class="hlt">bubbles</span> can be held together by interface forces is yet uncertain, and we use the available knowledge on surface energies to explore this problem. We call adhesion energy the surface energy change due to attachment of a crystal to a <span class="hlt">bubble</span>. We show that sticking a <span class="hlt">bubble</span> to a mineral substrate is always energetically favored over keeping <span class="hlt">bubble</span> and mineral separate. Because the adhesion energy is a strong function of the wetting angle, different minerals will be more strongly attached to <span class="hlt">bubbles</span> than others. In particular, oxide minerals will attach to a given <span class="hlt">bubble</span> much more strongly than any silicates. One interesting consequence of the attachment of grains to a <span class="hlt">bubble</span> is that this can cause these <span class="hlt">bubble</span>-crystal pairs to be neutrally buoyant, preventing <span class="hlt">bubble</span> <span class="hlt">rise</span> and crystal sinking. The criterion for buoyancy of a <span class="hlt">bubble</span>-crystal pair can be calculated as the condition when the apparent weight of the crystal and the <span class="hlt">bubble</span> are opposite and equal. If a <span class="hlt">bubble</span>-mineral pair is to remain joined, the binding force has to be provided by the adhesion force, which is also a strong function of the wetting angle. Since the adhesion force is linear on R, and the buoyancy force is proportional to R cubed, there is a critical <span class="hlt">bubble</span> radius</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H23I..04K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H23I..04K"><span>Scaling behavior of microbubbles <span class="hlt">rising</span> in water-saturated porous media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kong, X.; Ma, Y.; Scheuermann, A.; Bringemeier, D.; Galindo-Torres, S. A.; Saar, M. O.; Li, L.</p> <p>2015-12-01</p> <p>Gas transport in the form of discrete microbubbles in saturated porous media is of importance in a number of processes relevant to many geo-environmental and engineering systems such as <span class="hlt">bubbling</span> of greenhouse gases in river and sea beds, hydrocarbon gas migration in coal cleats and rock fractures, and air sparging for remediation of soil contaminated with volatile organic compounds. Under the assumption of no or minor volume expansion during gravity-driven migration, the transport of a single microbubble can be well described using various drag force models. However, not enough attention has been paid to the collective behavior of microbubbles during their ascend as a plume through the saturated porous medium, involving dynamic interactions between individual <span class="hlt">bubbles</span>, <span class="hlt">bubbles</span> and the ambient fluid, as well as <span class="hlt">bubbles</span> and the solid matrix. With our quasi-2D, lab-scale microbubble migration experiments, where <span class="hlt">bubbles</span> are continuously released from a diffuser at the bottom of a porous bed of hydrated gel beads, we establish a scaling relationship between the gas (<span class="hlt">bubble</span>) release rate and various <span class="hlt">characteristic</span> parameters of the <span class="hlt">bubble</span> plume, such as plume tip velocity, plume width, and breakthrough time of the plume front. We find that the <span class="hlt">characteristic</span> width of the <span class="hlt">bubble</span> plume varies as a power of both the gas release rate and the bed thickness, with exponents of 0.2 and 0.4, respectively. Moreover, the <span class="hlt">characteristic</span> breakthrough time also scales with both the gas release rate and the bed thickness with power-law exponents of -0.4 and 1.2, respectively. The mean pore-water velocity of the circulating ambient water also follows a power-law relationship with the gas release rate being an exponent of 0.6 of the gas release rate. This can be quantitatively proven using a simplified momentum exchange model together with the above power-law exponents for the <span class="hlt">bubble</span> plume. These analyses on the experimental results are carried out on the basis of non</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020014835&hterms=crisis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dcrisis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020014835&hterms=crisis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dcrisis"><span>Modeling of Vapor <span class="hlt">Bubble</span> Growth Under Nucleate Boiling Conditions in Reduced Gravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Buyevich, Yu A.; Webbon, Bruce W.</p> <p>1995-01-01</p> <p>A dynamic model is developed to describe the evolution of a vapor <span class="hlt">bubble</span> growing at a nucleation site on a superheated surface under arbitrary gravity. The <span class="hlt">bubble</span> is separated from the surface by a thin microlayer and grows due to the evaporation from the microlayer interface. The average thickness of the microlayer increases as the <span class="hlt">bubble</span> expands along the surface if the evaporation rate is lower than some critical value. The corresponding threshold value of the surface temperature has to be associated with the burn-out crisis. Two main reasons make for <span class="hlt">bubble</span> separation, which are the buoyancy force and a force caused by the vapor momentum that comes to the <span class="hlt">bubble</span> with vapor molecules. The latter force is somewhat diminished if condensation takes place at the upper <span class="hlt">bubble</span> surface in subcooled liquids. The action of the said forces is opposed by inertia of the additional mass of liquid as the <span class="hlt">bubble</span> center <span class="hlt">rises</span> above the surface and by inertia of liquid being expelled by the growing <span class="hlt">bubble</span> in radial directions. An extra pressure force arises due to the liquid inflow into the microlayer with a finite velocity. The last force helps in holding the <span class="hlt">bubble</span> close to the surface during an initial stage of <span class="hlt">bubble</span> evolution. Two limiting regimes with distinctly different properties can be singled out, depending on which of the forces that favor <span class="hlt">bubble</span> detachment dominates. Under conditions of moderately reduced gravity, the situation is much the same as in normal gravity, although the <span class="hlt">bubble</span> detachment volume increases as gravity diminishes. In microgravity, the buoyancy force is negligible. Then the <span class="hlt">bubble</span> is capable of staying near the surface for a long time, with intensive evaporation from the microlayer. It suggests a drastic change in the physical mechanism of heat removal as gravity falls below a certain sufficiently low level. Inferences of the model and conclusions pertaining to effects caused on heat transfer processes by changes in <span class="hlt">bubble</span> hydrodynamics induced</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008RScI...79l5105L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008RScI...79l5105L"><span><span class="hlt">Bubble</span> velocity, diameter, and void fraction measurements in a multiphase flow using fiber optic reflectometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lim, Ho-Joon; Chang, Kuang-An; Su, Chin B.; Chen, Chi-Yueh</p> <p>2008-12-01</p> <p>A fiber optic reflectometer (FOR) technique featuring a single fiber probe is investigated for its feasibility of measuring the <span class="hlt">bubble</span> velocity, diameter, and void fraction in a multiphase flow. The method is based on the interference of the scattered signal from the <span class="hlt">bubble</span> surface with the Fresnel reflection signal from the tip of the optical fiber. Void fraction is obtained with a high accuracy if an appropriate correction is applied to compensate the underestimated measurement value. Velocity information is accurately obtained from the reflected signals before the fiber tip touches the <span class="hlt">bubble</span> surface so that several factors affecting the traditional dual-tip probes such as blinding, crawling, and drifting effects due to the interaction between the probe and <span class="hlt">bubbles</span> can be prevented. The coherent signals reflected from both the front and rear ends of a <span class="hlt">bubble</span> can provide velocity information. Deceleration of <span class="hlt">rising</span> <span class="hlt">bubbles</span> and particles due to the presence of the fiber probe is observed when they are very close to the fiber tip. With the residence time obtained, the <span class="hlt">bubble</span> chord length can be determined by analyzing the coherent signal for velocity determination before the deceleration starts. The <span class="hlt">bubble</span> diameters are directly obtained from analyzing the signals of the <span class="hlt">bubbles</span> that contain velocity information. The chord lengths of these <span class="hlt">bubbles</span> measured by FOR represent the <span class="hlt">bubble</span> diameters when the <span class="hlt">bubble</span> shape is spherical or represent the minor axes when the <span class="hlt">bubble</span> shape is ellipsoidal. The velocity and size of <span class="hlt">bubbles</span> obtained from the FOR measurements are compared with those obtained simultaneously using a high speed camera.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6761474-analysis-boundary-conditions-hele-shaw-bubble','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6761474-analysis-boundary-conditions-hele-shaw-bubble"><span>Analysis of the boundary conditions for a Hele--Shaw <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Burgess, D.; Foster, M.R.</p> <p>1990-07-01</p> <p>Effective boundary conditions are derived to be used with the classical Hele--Shaw equations in calculating the shape and motion of a Hele--Shaw <span class="hlt">bubble</span>. The main assumptions of this analysis are that the displaced fluid wets the plates, and that the capillary number Ca and the ratio of gap width to <span class="hlt">characteristic</span> <span class="hlt">bubble</span> length {epsilon} are both small. In a small region at the sides of the <span class="hlt">bubble</span>, it is found that the thin-film thickness scales with {epsilon}{sup 2/5} Ca{sup 4/5}, rather than the Ca{sup 2/3} scaling that is valid over most of the thin film above and below the <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29073483','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29073483"><span>Effect of ultrasound on dynamics <span class="hlt">characteristic</span> of the cavitation <span class="hlt">bubble</span> in grinding fluids during honing process.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guo, Ce; Zhu, Xijing</p> <p>2018-03-01</p> <p>The effect of ultrasound on generating and controlling the cavitation <span class="hlt">bubble</span> of the grinding fluid during ultrasonic vibration honing was investigated. The grinding fluid on the surface of the honing stone was measured by utilizing the digital microscope VHX-600ESO. Based on analyzing the cavitation mechanism of the grinding fluid, the <span class="hlt">bubble</span> dynamics model under conventional honing (CH) and ultrasonic vibration honing (UVH) was established respectively. Difference of dynamic behaviors of the <span class="hlt">bubble</span> between the cases in UVH and CH was compared respectively, and the effects of acoustic amplitude and ultrasonic frequency on the <span class="hlt">bubble</span> dynamics were simulated numerically using the Runge-Kutta fourth order method with variable step size adaptive control. Finally, the cavitation intensity of grinding fluids under ultrasound was measured quantitatively using acoustimeter. The results showed that the grinding fluid subjected to ultrasound can generate many <span class="hlt">bubbles</span> and further forms numerous groups of araneose cavitation <span class="hlt">bubbles</span> on the surface of the honing stone. The oscillation of the <span class="hlt">bubble</span> under UVH is more intense than the case under CH, and the maximum velocity of the <span class="hlt">bubble</span> wall under UVH is higher two magnitudes than the case under CH. For lower acoustic amplitude, the dynamic behaviors of the <span class="hlt">bubble</span> under UVH are similar to that case under CH. As increasing acoustic amplitude, the cavitation intensity of the <span class="hlt">bubble</span> is growing increased. Honing pressure has an inhabitation effect on cavitation effect of the grinding fluid. The perfect performance of cavitation of the grinding fluid can be obtained when the device of UVH is in the resonance. However, the cavitation intensity of the grinding fluid can be growing weakened with increasing ultrasonic frequency, when the device of UVH is in the off-resonance. The experimental results agree with the theoretical and numerical analysis, which provides a method for exploring applications of the cavitation effect in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/328500','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/328500"><span>Simulation studies of vapor <span class="hlt">bubble</span> generation by short-pulse lasers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Amendt, P.; London, R.A.; Strauss, M.</p> <p>1997-10-26</p> <p>Formation of vapor <span class="hlt">bubbles</span> is <span class="hlt">characteristic</span> of many applications of short-pulse lasers in medicine. An understanding of the dynamics of vapor <span class="hlt">bubble</span> generation is useful for developing and optimizing laser-based medical therapies. To this end, experiments in vapor <span class="hlt">bubble</span> generation with laser light deposited in an aqueous dye solution near a fiber-optic tip have been performed. Numerical hydrodynamic simulations have been developed to understand and extrapolate results from these experiments. Comparison of two-dimensional simulations with the experiment shows excellent agreement in tracking the <span class="hlt">bubble</span> evolution. Another regime of vapor <span class="hlt">bubble</span> generation is short-pulse laser interactions with melanosomes. Strong shock generationmore » and vapor <span class="hlt">bubble</span> generation are common physical features of this interaction. A novel effect of discrete absorption by melanin granules within a melanosome is studied as a possible role in previously reported high Mach number shocks.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70184329','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70184329"><span>Investigating the role of gas <span class="hlt">bubble</span> formation and entrapment in contaminated aquifers: Reactive transport modelling</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Amos, Richard T.; Mayer, K. Ulrich</p> <p>2006-01-01</p> <p>In many natural and contaminated aquifers, geochemical processes result in the production or consumption of dissolved gases. In cases where methanogenesis or denitrification occurs, the production of gases may result in the formation and growth of gas <span class="hlt">bubbles</span> below the water table. Near the water table, entrapment of atmospheric gases during water table <span class="hlt">rise</span> may provide a significant source of O2 to waters otherwise depleted in O2. Furthermore, the presence of <span class="hlt">bubbles</span> will affect the hydraulic conductivity of an aquifer, resulting in changes to the groundwater flow regime. The interactions between physical transport, biogeochemical processes, and gas <span class="hlt">bubble</span> formation, entrapment and release is complex and requires suitable analysis tools. The objective of the present work is the development of a numerical model capable of quantitatively assessing these processes. The multicomponent reactive transport code MIN3P has been enhanced to simulate <span class="hlt">bubble</span> growth and contraction due to in-situ gas production or consumption, <span class="hlt">bubble</span> entrapment due to water table <span class="hlt">rise</span> and subsequent re-equilibration of the <span class="hlt">bubble</span> with ambient groundwater, and permeability changes due to trapped gas phase saturation. The resulting formulation allows for the investigation of complex geochemical systems where microbially mediated redox reactions both produce and consume gases as well as affect solution chemistry, alkalinity, and pH. The enhanced model has been used to simulate processes in a petroleum hydrocarbon contaminated aquifer where methanogenesis is an important redox process. The simulations are constrained by data from a crude oil spill site near Bemidji, MN. Our results suggest that permeability reduction in the methanogenic zone due to in-situ formation of gas <span class="hlt">bubbles</span>, and dissolution of entrapped atmospheric <span class="hlt">bubbles</span> near the water table, both work to attenuate the dissolved gas plume emanating from the source zone. Furthermore, the simulations demonstrate that under the given</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JCHyd..87..123A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JCHyd..87..123A"><span>Investigating the role of gas <span class="hlt">bubble</span> formation and entrapment in contaminated aquifers: Reactive transport modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amos, Richard T.; Ulrich Mayer, K.</p> <p>2006-09-01</p> <p>In many natural and contaminated aquifers, geochemical processes result in the production or consumption of dissolved gases. In cases where methanogenesis or denitrification occurs, the production of gases may result in the formation and growth of gas <span class="hlt">bubbles</span> below the water table. Near the water table, entrapment of atmospheric gases during water table <span class="hlt">rise</span> may provide a significant source of O 2 to waters otherwise depleted in O 2. Furthermore, the presence of <span class="hlt">bubbles</span> will affect the hydraulic conductivity of an aquifer, resulting in changes to the groundwater flow regime. The interactions between physical transport, biogeochemical processes, and gas <span class="hlt">bubble</span> formation, entrapment and release is complex and requires suitable analysis tools. The objective of the present work is the development of a numerical model capable of quantitatively assessing these processes. The multicomponent reactive transport code MIN3P has been enhanced to simulate <span class="hlt">bubble</span> growth and contraction due to in-situ gas production or consumption, <span class="hlt">bubble</span> entrapment due to water table <span class="hlt">rise</span> and subsequent re-equilibration of the <span class="hlt">bubble</span> with ambient groundwater, and permeability changes due to trapped gas phase saturation. The resulting formulation allows for the investigation of complex geochemical systems where microbially mediated redox reactions both produce and consume gases as well as affect solution chemistry, alkalinity, and pH. The enhanced model has been used to simulate processes in a petroleum hydrocarbon contaminated aquifer where methanogenesis is an important redox process. The simulations are constrained by data from a crude oil spill site near Bemidji, MN. Our results suggest that permeability reduction in the methanogenic zone due to in-situ formation of gas <span class="hlt">bubbles</span>, and dissolution of entrapped atmospheric <span class="hlt">bubbles</span> near the water table, both work to attenuate the dissolved gas plume emanating from the source zone. Furthermore, the simulations demonstrate that under the given</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvE..96c3114S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvE..96c3114S"><span>Luminescence from cavitation <span class="hlt">bubbles</span> deformed in uniform pressure gradients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed</p> <p>2017-09-01</p> <p>Presented here are observations that demonstrate how the deformation of millimetric cavitation <span class="hlt">bubbles</span> by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced <span class="hlt">bubbles</span> in water. By varying the <span class="hlt">bubble</span> size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical <span class="hlt">bubble</span> collapses. Luminescence was detected for <span class="hlt">bubbles</span> of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced <span class="hlt">bubbles</span>. The relative luminescence energy was found to rapidly decrease as a function of the <span class="hlt">bubble</span> asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the <span class="hlt">characteristic</span> parameters of <span class="hlt">bubble</span>-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the <span class="hlt">bubble</span> and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each <span class="hlt">bubble</span> collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28455642','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28455642"><span>Double <span class="hlt">bubble</span> with the big-<span class="hlt">bubble</span> technique during deep anterior lamellar keratoplasty.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wise, Stephanie; Dubord, Paul; Yeung, Sonia N</p> <p>2017-04-28</p> <p>To report a case of intraoperative double <span class="hlt">bubble</span> that formed during big-<span class="hlt">bubble</span> DALK surgery in a patient with corneal scarring secondary to herpetic stromal keratitis. Case report. A 22 year old woman presented with a large corneal scar, likely secondary to previous herpetic stromal keratitis. She underwent big-<span class="hlt">bubble</span> DALK surgery for visual rehabilitation. Intraoperatively, a mixed <span class="hlt">bubble</span> with persistent type 2 <span class="hlt">bubble</span> postoperatively was noted. The second <span class="hlt">bubble</span> resorbed with clearance of the graft and good visual outcome after 6 weeks. This case report describes the unusual development of a mixed <span class="hlt">bubble</span> during big-<span class="hlt">bubble</span> DALK surgery. This graft cleared with resolution of the second <span class="hlt">bubble</span> postoperatively without further surgical intervention.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990064092','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990064092"><span><span class="hlt">Bubble</span> Generation in a Continuous Liquid Flow Under Reduced Gravity Conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pais, Salvatore Cezar</p> <p>1999-01-01</p> <p>The present work reports a study of <span class="hlt">bubble</span> generation under reduced gravity conditions for both co-flow and cross-flow configurations. Experiments were performed aboard the DC-9 Reduced Gravity Aircraft at NASA Glenn Research Center, using an air-water system. Three different flow tube diameters were used: 1.27, 1.9, and 2.54 cm. Two different ratios of air injection nozzle to tube diameters were considered: 0.1 and 0.2. Gas and liquid volumetric flow rates were varied from 10 to 200 ml/s. It was experimentally observed that with increasing superficial liquid velocity, the <span class="hlt">bubbles</span> generated decreased in size. The <span class="hlt">bubble</span> diameter was shown to increase with increasing air injection nozzle diameters. As the tube diameter was increased, the size of the detached <span class="hlt">bubbles</span> increased. Likewise, as the superficial liquid velocity was increased, the frequency of <span class="hlt">bubble</span> formation increased and thus the time to detach forming <span class="hlt">bubbles</span> decreased. Independent of the flow configuration (for either single nozzle or multiple nozzle gas injection), void fraction and hence flow regime transition can be controlled in a somewhat precise manner by solely varying the gas and liquid volumetric flow rates. On the other hand, it is observed that uniformity of <span class="hlt">bubble</span> size can be controlled more accurately by using single nozzle gas injection than by using multiple port injection, since this latter system gives <span class="hlt">rise</span> to unpredictable coalescence of adjacent <span class="hlt">bubbles</span>. A theoretical model, based on an overall force balance, is employed to study single <span class="hlt">bubble</span> generation in the dynamic and <span class="hlt">bubbly</span> flow regime. Under conditions of reduced gravity, the gas momentum flux enhances <span class="hlt">bubble</span> detachment; however, the surface tension forces at the nozzle tip inhibits <span class="hlt">bubble</span> detachment. Liquid drag and inertia can act either as attaching or detaching force, depending on the relative velocity of the <span class="hlt">bubble</span> with respect to the surrounding liquid. Predictions of the theoretical model compare well with performed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988MTB....19...83E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988MTB....19...83E"><span><span class="hlt">Bubbling</span> at high flow rates in inviscid and viscous liquids (slags)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engh, T. Abel; Nilmani, M.</p> <p>1988-02-01</p> <p>The behavior of gas discharging into melts at high velocities but still in the <span class="hlt">bubbling</span> regime has been investigated in a laboratory modeling study for constant flow conditions. Air or helium was injected through a vertical tuyere into water, zinc-chloride, and aqueous glycerol solutions. High speed cinematography and pressure measurements in the tuyere have been carried out simultaneously. Pressure fluctuations at the injection point were monitored and correlated to the mode of <span class="hlt">bubble</span> formation. The effects of high gas flow rates and high liquid viscosities have been examined in particular. Flow rates were employed up to 10-3 m3/s and viscosity to 0.5 Ns/m2. In order to attain a high gas momentum, the tuyere diameter was only 3 x 10-3 m. The experimental conditions and modeling liquids were chosen with special reference to the established practice of submerged gas injection to treat nonferrous slags. Such slags can be highly viscous. <span class="hlt">Bubble</span> volume is smaller than that calculated from existing models such as those given by Davidson and Schüler10,11 due to the effect of gas momentum elongating the <span class="hlt">bubbles</span>. On the other hand, viscosity tends to retard the <span class="hlt">bubble</span> <span class="hlt">rise</span> velocity, thus increasing volumes. To take elongation into account, a mathematical model is presented that assumes a prolate ellipsoidal shape of the <span class="hlt">bubbles</span>. The unsteady potential flow equations for the liquid are solved for this case. Viscous effects are taken into account by noting that flow deviates from irrotational motion only in a thin boundary layer along the surface of the <span class="hlt">bubble</span>. Thus, drag on the <span class="hlt">bubble</span> can be obtained by calculating the viscous energy dissipation for potential flow past an ellipse. The time-dependent inertia coefficient for the ellipsoid is found by equating the vertical pressure increase inside and outside the <span class="hlt">bubble</span>. This pressure change in the <span class="hlt">bubble</span> is obtained by assuming that gas enters as a homogeneous jet and then calculating the stagnation pressure at the apex of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25350655','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25350655"><span>A <span class="hlt">bubble</span>-based microfluidic gas sensor for gas chromatographs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bulbul, Ashrafuzzaman; Kim, Hanseup</p> <p>2015-01-07</p> <p>We report a new proof-of-concept <span class="hlt">bubble</span>-based gas sensor for a gas chromatography system, which utilizes the unique relationship between the diameters of the produced <span class="hlt">bubbles</span> with the gas types and mixture ratios as a sensing element. The <span class="hlt">bubble</span>-based gas sensor consists of gas and liquid channels as well as a nozzle to produce gas <span class="hlt">bubbles</span> through a micro-structure. It utilizes custom-developed software and an optical camera to statistically analyze the diameters of the produced <span class="hlt">bubbles</span> in flow. The fabricated gas sensor showed that five types of gases (CO2, He, H2, N2, and CH4) produced (1) unique volumes of 0.44, 0.74, 1.03, 1.28, and 1.42 nL (0%, 68%, 134%, 191%, and 223% higher than that of CO2) and (2) <span class="hlt">characteristic</span> linear expansion coefficients (slope) of 1.38, 2.93, 3.45, 5.06, and 5.44 nL/(kPa (μL s(-1))(-1)). The gas sensor also demonstrated that (3) different gas mixture ratios of CO2 : N2 (100 : 0, 80 : 20, 50 : 50, 20 : 80 and 0 : 100) generated <span class="hlt">characteristic</span> <span class="hlt">bubble</span> diameters of 48.95, 77.99, 71.00, 78.53 and 99.50 μm, resulting in a linear coefficient of 10.26 μm (μL s(-1))(-1). It (4) successfully identified an injection (0.01 μL) of pentane (C5) into a continuous carrier gas stream of helium (He) by monitoring <span class="hlt">bubble</span> diameters and creating a chromatogram and demonstrated (5) the output stability within only 5.60% variation in 67 tests over a month.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhFl...27f3103W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhFl...27f3103W"><span>Numerical modeling of <span class="hlt">bubble</span> dynamics in viscoelastic media with relaxation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Warnez, M. T.; Johnsen, E.</p> <p>2015-06-01</p> <p>Cavitation occurs in a variety of non-Newtonian fluids and viscoelastic materials. The large-amplitude volumetric oscillations of cavitation <span class="hlt">bubbles</span> give <span class="hlt">rise</span> to high temperatures and pressures at collapse, as well as induce large and rapid deformation of the surroundings. In this work, we develop a comprehensive numerical framework for spherical <span class="hlt">bubble</span> dynamics in isotropic media obeying a wide range of viscoelastic constitutive relationships. Our numerical approach solves the compressible Keller-Miksis equation with full thermal effects (inside and outside the <span class="hlt">bubble</span>) when coupled to a highly generalized constitutive relationship (which allows Newtonian, Kelvin-Voigt, Zener, linear Maxwell, upper-convected Maxwell, Jeffreys, Oldroyd-B, Giesekus, and Phan-Thien-Tanner models). For the latter two models, partial differential equations (PDEs) must be solved in the surrounding medium; for the remaining models, we show that the PDEs can be reduced to ordinary differential equations. To solve the general constitutive PDEs, we present a Chebyshev spectral collocation method, which is robust even for violent collapse. Combining this numerical approach with theoretical analysis, we simulate <span class="hlt">bubble</span> dynamics in various viscoelastic media to determine the impact of relaxation time, a constitutive parameter, on the associated physics. Relaxation time is found to increase <span class="hlt">bubble</span> growth and permit rebounds driven purely by residual stresses in the surroundings. Different regimes of oscillations occur depending on the relaxation time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474959','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474959"><span>Numerical modeling of <span class="hlt">bubble</span> dynamics in viscoelastic media with relaxation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Warnez, M. T.; Johnsen, E.</p> <p>2015-01-01</p> <p>Cavitation occurs in a variety of non-Newtonian fluids and viscoelastic materials. The large-amplitude volumetric oscillations of cavitation <span class="hlt">bubbles</span> give <span class="hlt">rise</span> to high temperatures and pressures at collapse, as well as induce large and rapid deformation of the surroundings. In this work, we develop a comprehensive numerical framework for spherical <span class="hlt">bubble</span> dynamics in isotropic media obeying a wide range of viscoelastic constitutive relationships. Our numerical approach solves the compressible Keller–Miksis equation with full thermal effects (inside and outside the <span class="hlt">bubble</span>) when coupled to a highly generalized constitutive relationship (which allows Newtonian, Kelvin–Voigt, Zener, linear Maxwell, upper-convected Maxwell, Jeffreys, Oldroyd-B, Giesekus, and Phan-Thien-Tanner models). For the latter two models, partial differential equations (PDEs) must be solved in the surrounding medium; for the remaining models, we show that the PDEs can be reduced to ordinary differential equations. To solve the general constitutive PDEs, we present a Chebyshev spectral collocation method, which is robust even for violent collapse. Combining this numerical approach with theoretical analysis, we simulate <span class="hlt">bubble</span> dynamics in various viscoelastic media to determine the impact of relaxation time, a constitutive parameter, on the associated physics. Relaxation time is found to increase <span class="hlt">bubble</span> growth and permit rebounds driven purely by residual stresses in the surroundings. Different regimes of oscillations occur depending on the relaxation time. PMID:26130967</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/875130','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/875130"><span><span class="hlt">Bubble</span> diagnostics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Visuri, Steven R.; Mammini, Beth M.; Da Silva, Luiz B.; Celliers, Peter M.</p> <p>2003-01-01</p> <p>The present invention is intended as a means of diagnosing the presence of a gas <span class="hlt">bubble</span> and incorporating the information into a feedback system for opto-acoustic thrombolysis. In opto-acoustic thrombolysis, pulsed laser radiation at ultrasonic frequencies is delivered intraluminally down an optical fiber and directed toward a thrombus or otherwise occluded vessel. Dissolution of the occlusion is therefore mediated through ultrasonic action of propagating pressure or shock waves. A vapor <span class="hlt">bubble</span> in the fluid surrounding the occlusion may form as a result of laser irradiation. This vapor <span class="hlt">bubble</span> may be used to directly disrupt the occlusion or as a means of producing a pressure wave. It is desirable to detect the formation and follow the lifetime of the vapor <span class="hlt">bubble</span>. Knowledge of the <span class="hlt">bubble</span> formation and lifetime yields critical information as to the maximum size of the <span class="hlt">bubble</span>, density of the absorbed radiation, and properties of the absorbing material. This information can then be used in a feedback system to alter the irradiation conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JFST....3..116O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JFST....3..116O"><span>Propagation of Pressure Waves, Caused by a Thermal Shock, in Liquid Metals Containing Gas <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okita, Kohei; Takagi, Shu; Matsumoto, Yoichiro</p> <p></p> <p>The propagation of pressure waves caused by a thermal shock in liquid mercury containing micro gas <span class="hlt">bubbles</span> has been simulated numerically. In the present study, we clarify the influences of the introduced <span class="hlt">bubble</span> size and void fraction on the absorption of thermal expansion of liquid mercury and attenuation of pressure waves. The mass, momentum and energy conservation equations for both <span class="hlt">bubbly</span> mixture and gas inside each <span class="hlt">bubble</span> are solved, in which the <span class="hlt">bubble</span> dynamics is represented by the Keller equation. The results show that when the initial void fraction is larger than the rate of the thermal expansion of liquid mercury, the pressure <span class="hlt">rise</span> caused by the thermal expansion decreases with decreasing the <span class="hlt">bubble</span> radius, because of the increase of the natural frequency of <span class="hlt">bubbly</span> mixture. On the other hand, as the <span class="hlt">bubble</span> radius increases, the peak of pressure waves which propagate at the sound speed of mixture decreases gradually due to the dispersion effect of mixture. When the natural frequency of the mixture with large <span class="hlt">bubbles</span> is lower than that of the thremal shock, the peak pressure at the wall increases because the pressure waves propagate through the mixture at the sound speed of liquid mercury. The comparison of the results with and without heat transfer through the gas liquid interface shows that the pressure waves are attenuated greatly by the thermal damping effect with the decrease of the void fraction which enhances the nonlinearity of <span class="hlt">bubble</span> oscillation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/20002430-analysis-three-dimensional-structure-bubble-wake-using-piv-galilean-decomposition','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/20002430-analysis-three-dimensional-structure-bubble-wake-using-piv-galilean-decomposition"><span>Analysis of the three-dimensional structure of a <span class="hlt">bubble</span> wake using PIV and Galilean decomposition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hassan, Y.A.; Schmidl, W.D.; Ortiz-Villafuerte, J.</p> <p>1999-07-01</p> <p><span class="hlt">Bubbly</span> flow plays a key role in a variety of natural and industrial processes. An accurate and complete description of the phase interactions in two-phase <span class="hlt">bubbly</span> flow is not available at this time. These phase interactions are, in general, always three-dimensional and unsteady. Therefore, measurement techniques utilized to obtain qualitative and quantitative data from two-phase flow should be able to acquire transient and three-dimensional data, in order to provide information to test theoretical models and numerical simulations. Even for dilute <span class="hlt">bubble</span> flows, in which <span class="hlt">bubble</span> interaction is at a minimum, the turbulent motion of the liquid generated by the bubblemore » is yet to be completely understood. For many years, the design of systems with <span class="hlt">bubbly</span> flows was based primarily on empiricism. Dilute <span class="hlt">bubbly</span> flows are an extension of single <span class="hlt">bubble</span> dynamics, and therefore improvements in the description and modeling of single <span class="hlt">bubble</span> motion, the flow field around the <span class="hlt">bubble</span>, and the dynamical interactions between the <span class="hlt">bubble</span> and the flow will consequently improve <span class="hlt">bubbly</span> flow modeling. The improved understanding of the physical phenomena will have far-reaching benefits in upgrading the operation and efficiency of current processes and in supporting the development of new and innovative approaches. A stereoscopic particle image velocimetry measurement of the flow generated by the passage of a single air-<span class="hlt">bubble</span> <span class="hlt">rising</span> in stagnant water, in a circular pipe is presented. Three-dimensional velocity fields within the measurement zone were obtained. Ensemble-averaged instantaneous velocities for a specific <span class="hlt">bubble</span> path were calculated and interpolated to obtain mean three-dimensional velocity fields. A Galilean velocity decomposition is used to study the vorticity generated in the flow.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20365474','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20365474"><span>Formation and evolution of <span class="hlt">bubbly</span> screens in confined oscillating <span class="hlt">bubbly</span> liquids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shklyaev, Sergey; Straube, Arthur V</p> <p>2010-01-01</p> <p>We consider the dynamics of dilute monodisperse <span class="hlt">bubbly</span> liquid confined by two plane solid walls and subject to small-amplitude high-frequency oscillations normal to the walls. The initial state corresponds to the uniform distribution of <span class="hlt">bubbles</span> and motionless liquid. The period of external driving is assumed much smaller than typical relaxation times for a single <span class="hlt">bubble</span> but larger than the period of volume eigenoscillations. The time-averaged description accounting for the two-way coupling between the liquid and the <span class="hlt">bubbles</span> is applied. We show that the model predicts accumulation of <span class="hlt">bubbles</span> in thin sheets parallel to the walls. These singular structures, which are formally characterized by infinitely thin width and infinitely high concentration, are referred to as <span class="hlt">bubbly</span> screens. The formation of a <span class="hlt">bubbly</span> screen is described analytically in terms of a self-similar solution, which is in agreement with numerical simulations. We study the evolution of <span class="hlt">bubbly</span> screens and detect a one-dimensional stationary state, which is shown to be unconditionally unstable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvE..81a6321S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvE..81a6321S"><span>Formation and evolution of <span class="hlt">bubbly</span> screens in confined oscillating <span class="hlt">bubbly</span> liquids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shklyaev, Sergey; Straube, Arthur V.</p> <p>2010-01-01</p> <p>We consider the dynamics of dilute monodisperse <span class="hlt">bubbly</span> liquid confined by two plane solid walls and subject to small-amplitude high-frequency oscillations normal to the walls. The initial state corresponds to the uniform distribution of <span class="hlt">bubbles</span> and motionless liquid. The period of external driving is assumed much smaller than typical relaxation times for a single <span class="hlt">bubble</span> but larger than the period of volume eigenoscillations. The time-averaged description accounting for the two-way coupling between the liquid and the <span class="hlt">bubbles</span> is applied. We show that the model predicts accumulation of <span class="hlt">bubbles</span> in thin sheets parallel to the walls. These singular structures, which are formally characterized by infinitely thin width and infinitely high concentration, are referred to as <span class="hlt">bubbly</span> screens. The formation of a <span class="hlt">bubbly</span> screen is described analytically in terms of a self-similar solution, which is in agreement with numerical simulations. We study the evolution of <span class="hlt">bubbly</span> screens and detect a one-dimensional stationary state, which is shown to be unconditionally unstable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....9421A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....9421A"><span>Acoustic observations of gas <span class="hlt">bubble</span> streams in the NW Black Sea as a method for estimation of gas flux from vent sites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Artemov, Yu. G.</p> <p>2003-04-01</p> <p>Relatively recent discovery of the natural CH_4 gas seepage from the sea bed had action upon the philosophy of CH_4 contribution to global budgets. So far as numerous gas vent sites are known, an acceptable method for released gas quantification is required. In particular, the questions should be answered as follows: 1) how much amount of gas comes into the water column due to a certain <span class="hlt">bubble</span> stream, 2) how much amount of gas comes into the water column due to a certain seepage area of the see floor, 3) how much amount of gas diffuses into the water and how much gas phase enters the atmosphere. Echo-sounder is the habitual equipment for detecting gas plumes (flares) in the water column. To provide observations of gas seeps with <span class="hlt">bubbles</span> tracking, single target and volume backscattering strength measurements, we use installed on board the R/V "Professor Vodyanitskiy" dual frequency (38 and 120 kHz) split-beam scientific echo-sounder SIMRAD EK-500. Dedicated software is developed to extract from the raw echo data and to handle the definite information for analyses of gas <span class="hlt">bubble</span> streams features. This improved hydroacoustic techniques allows to determine gas <span class="hlt">bubbles</span> size spectrum at different depths through the water column as well as <span class="hlt">rise</span> velocity of <span class="hlt">bubbles</span> of different sizes. For instance, <span class="hlt">bubble</span> of 4.5 mm diameter has <span class="hlt">rising</span> speed of 25.8 cm/sec at 105 m depth, while <span class="hlt">bubble</span> of 1.7 mm diameter has <span class="hlt">rising</span> speed of 16.3 cm/sec at 32 m depth. Using volume backscattering measurements in addition, it is possible to evaluate flux of the gas phase produced by methane <span class="hlt">bubble</span> streams and to learn of its fate in the water column. Ranking of various gas plumes by flux rate value is available also. In this presentation results of acoustic observations at the shallow NW Black Sea seepage area are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JOM....70b.229Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JOM....70b.229Z"><span>Computational Fluid Dynamics-Population Balance Model Simulation of Effects of Cell Design and Operating Parameters on Gas-Liquid Two-Phase Flows and <span class="hlt">Bubble</span> Distribution <span class="hlt">Characteristics</span> in Aluminum Electrolysis Cells</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhan, Shuiqing; Wang, Junfeng; Wang, Zhentao; Yang, Jianhong</p> <p>2018-02-01</p> <p>The effects of different cell design and operating parameters on the gas-liquid two-phase flows and <span class="hlt">bubble</span> distribution <span class="hlt">characteristics</span> under the anode bottom regions in aluminum electrolysis cells were analyzed using a three-dimensional computational fluid dynamics-population balance model. These parameters include inter-anode channel width, anode-cathode distance (ACD), anode width and length, current density, and electrolyte depth. The simulations results show that the inter-anode channel width has no significant effect on the gas volume fraction, electrolyte velocity, and <span class="hlt">bubble</span> size. With increasing ACD, the above values decrease and more uniform <span class="hlt">bubbles</span> can be obtained. Different effects of the anode width and length can be concluded in different cell regions. With increasing current density, the gas volume fraction and electrolyte velocity increase, but the <span class="hlt">bubble</span> size keeps nearly the same. Increasing electrolyte depth decreased the gas volume fraction and <span class="hlt">bubble</span> size in particular areas and the electrolyte velocity increased.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870057647&hterms=Separation+Techniques&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSeparation%2BTechniques','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870057647&hterms=Separation+Techniques&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSeparation%2BTechniques"><span>A unique measurement technique to study laminar-separation <span class="hlt">bubble</span> <span class="hlt">characteristics</span> on an airfoil</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stack, J. P.; Mangalam, S. M.; Berry, S. A.</p> <p>1987-01-01</p> <p>A 'nonintrusive', multielement heat-transfer sensor was designed to study laminar-separation <span class="hlt">bubble</span> <span class="hlt">characteristics</span> on a NASA LRN (1)-1010 low-Reynolds number airfoil. The sensor consists of 30 individual nickel films, vacuum-deposited on a thin substrate (0.05 mm) that was bonded to the airfoil model with the sensor array placed streamwise on the airfoil upper surface. Experiments were conducted on a 15-cm chord model in the 50,000-300,000 chord Reynolds number range. Time history as well as spectral analysis of signals from surface film gauges were simultaneously obtained to determine the location of laminar separation and the subsequent behavior of the separated shear layer. In addition to the successful determination of laminar separation, a new phenomenon involving a large phase shift in dynamic shear stresses across the separation and reattachment points was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMOS33C1372W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMOS33C1372W"><span>Oceanic Gas <span class="hlt">Bubble</span> Measurements Using an Acoustic <span class="hlt">Bubble</span> Spectrometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, S. J.; Baschek, B.; Deane, G.</p> <p>2008-12-01</p> <p>Gas <span class="hlt">bubble</span> injection by breaking waves contributes significantly to the exchange of gases between atmosphere and ocean at high wind speeds. In this respect, CO2 is primarily important for the global ocean and climate, while O2 is especially relevant for ecosystems in the coastal ocean. For measuring oceanic gas <span class="hlt">bubble</span> size distributions, a commercially available Dynaflow Acoustic <span class="hlt">Bubble</span> Spectrometer (ABS) has been modified. Two hydrophones transmit and receive selected frequencies, measuring attenuation and absorption. Algorithms are then used to derive <span class="hlt">bubble</span> size distributions. Tank test were carried out in order to test the instrument performance.The software algorithms were compared with Commander and Prosperetti's method (1989) of calculating sound speed ratio and attenuation for a known <span class="hlt">bubble</span> distribution. Additional comparisons with micro-photography were carried out in the lab and will be continued during the SPACE '08 experiment in October 2008 at Martha's Vineyard Coastal Observatory. The measurements of gas <span class="hlt">bubbles</span> will be compared to additional parameters, such as wind speed, wave height, white cap coverage, or dissolved gases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRC..122.2671L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRC..122.2671L"><span>On the role of sea-state in <span class="hlt">bubble</span>-mediated air-sea gas flux during a winter storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Jun-Hong; Emerson, Steven R.; D'Asaro, Eric A.; McNeil, Craig L.; Harcourt, Ramsey R.; Sullivan, Peter P.; Yang, Bo; Cronin, Meghan F.</p> <p>2017-04-01</p> <p>Oceanic <span class="hlt">bubbles</span> play an important role in the air-sea exchange of weakly soluble gases at moderate to high wind speeds. A Lagrangian <span class="hlt">bubble</span> model embedded in a large eddy simulation model is developed to study <span class="hlt">bubbles</span> and their influence on dissolved gases in the upper ocean. The transient evolution of mixed-layer dissolved oxygen and nitrogen gases at Ocean Station Papa (50°N, 145°W) during a winter storm is reproduced with the model. Among different physical processes, gas <span class="hlt">bubbles</span> are the most important in elevating dissolved gas concentrations during the storm, while atmospheric pressure governs the variability of gas saturation anomaly (the relative departure of dissolved gas concentration from the saturation concentration). For the same wind speed, <span class="hlt">bubble</span>-mediated gas fluxes are larger during <span class="hlt">rising</span> wind with smaller wave age than during falling wind with larger wave age. Wave conditions are the primary cause for the <span class="hlt">bubble</span> gas flux difference: when wind strengthens, waves are less-developed with respect to wind, resulting in more frequent large breaking waves. <span class="hlt">Bubble</span> generation in large breaking waves is favorable for a large <span class="hlt">bubble</span>-mediated gas flux. The wave-age dependence is not included in any existing <span class="hlt">bubble</span>-mediated gas flux parameterizations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830027510','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830027510"><span>Acoustic <span class="hlt">bubble</span> removal method</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Trinh, E. H.; Elleman, D. D.; Wang, T. G. (Inventor)</p> <p>1983-01-01</p> <p>A method is described for removing <span class="hlt">bubbles</span> from a liquid bath such as a bath of molten glass to be used for optical elements. Larger <span class="hlt">bubbles</span> are first removed by applying acoustic energy resonant to a bath dimension to drive the larger <span class="hlt">bubbles</span> toward a pressure well where the <span class="hlt">bubbles</span> can coalesce and then be more easily removed. Thereafter, submillimeter <span class="hlt">bubbles</span> are removed by applying acoustic energy of frequencies resonant to the small <span class="hlt">bubbles</span> to oscillate them and thereby stir liquid immediately about the <span class="hlt">bubbles</span> to facilitate their breakup and absorption into the liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JVGR..285..129A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JVGR..285..129A"><span>Geyser preplay and eruption in a laboratory model with a <span class="hlt">bubble</span> trap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adelstein, Esther; Tran, Aaron; Saez, Carolina Muñoz; Shteinberg, Alexander; Manga, Michael</p> <p>2014-09-01</p> <p>We present visual observations and temperature measurements from a laboratory model of a geyser. Our model incorporates a <span class="hlt">bubble</span> trap, a zone in which vapor can accumulate in the geyser's subsurface plumbing, in a vertical conduit connected to a basal chamber. Analogous features have been identified at several natural geysers. We observe three types of eruptions: 1) <span class="hlt">rising</span> <span class="hlt">bubbles</span> eject a small volume of liquid in a weak spout (small eruption); 2) boiling occurs in the conduit above the <span class="hlt">bubble</span> trap (medium eruption); and 3) boiling occurs in the conduit and chamber (large eruption). In the last two cases, boiling in the conduit causes a rapid hydrostatic pressure drop that allows for the <span class="hlt">rise</span> and eruption of liquid water in a vigorous spout. Boiling initiates at depth rather than propagating downward from the surface. In a single eruption cycle, multiple small eruptions precede every medium and large eruption. At least one eruption cycle that culminates in a medium eruption (i.e., a quiescent period followed by a series of small eruptions leading up to a medium eruption) precedes every eruption cycle that culminates in a large eruption. We find that the transfer of fluid with high enthalpy to the upper conduit during small and medium eruptions is necessary to heat the upper conduit and prepare the system for the full boiling required for a large eruption. The placement of the <span class="hlt">bubble</span> trap midway up the conduit allows for more efficient heating of the upper conduit. Our model provides insight into the influence of conduit geometry on eruption style and the importance of heat transfer by smaller events in preparing the geyser system for eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17677349','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17677349"><span>Chaotic <span class="hlt">bubbling</span> and nonstagnant foams.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tufaile, Alberto; Sartorelli, José Carlos; Jeandet, Philippe; Liger-Belair, Gerard</p> <p>2007-06-01</p> <p>We present an experimental investigation of the agglomeration of <span class="hlt">bubbles</span> obtained from a nozzle working in different <span class="hlt">bubbling</span> regimes. This experiment consists of a continuous production of <span class="hlt">bubbles</span> from a nozzle at the bottom of a liquid column, and these <span class="hlt">bubbles</span> create a two-dimensional (2D) foam (or a <span class="hlt">bubble</span> raft) at the top of this column. The <span class="hlt">bubbles</span> can assemble in various dynamically stable arrangement, forming different kinds of foams in a liquid mixture of water and glycerol, with the effect that the <span class="hlt">bubble</span> formation regimes influence the foam obtained from this agglomeration of <span class="hlt">bubbles</span>. The average number of <span class="hlt">bubbles</span> in the foam is related to the <span class="hlt">bubble</span> formation frequency and the <span class="hlt">bubble</span> mean lifetime. The periodic <span class="hlt">bubbling</span> can generate regular or irregular foam, while a chaotic <span class="hlt">bubbling</span> only generates irregular foam.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5375841','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5375841"><span>A Micro <span class="hlt">Bubble</span> Structure Based Fabry–Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost <span class="hlt">Characteristics</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yan, Lu; Gui, Zhiguo; Wang, Guanjun; An, Yongquan; Gu, Jinyu; Zhang, Meiqin; Liu, Xinglin; Wang, Zhibin; Wang, Gao; Jia, Pinggang</p> <p>2017-01-01</p> <p>A high-sensitivity, low-cost, ultrathin, hollow fiber micro <span class="hlt">bubble</span> structure was proposed; such a <span class="hlt">bubble</span> can be used to develop a high-sensitivity strain sensor based on a Fabry–Perot interferometer (FPI). The micro <span class="hlt">bubble</span> is fabricated at the fiber tip by splicing a glass tube to a single mode fiber (SMF) and then the glass tube is filled with gas in order to expand and form a micro <span class="hlt">bubble</span>. The sensitivity of the strain sensor with a cavity length of about 155 μm and a <span class="hlt">bubble</span> wall thickness of about 6 μm was measured to be up to 8.14 pm/με. PMID:28282960</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28282960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28282960"><span>A Micro <span class="hlt">Bubble</span> Structure Based Fabry-Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost <span class="hlt">Characteristics</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Lu; Gui, Zhiguo; Wang, Guanjun; An, Yongquan; Gu, Jinyu; Zhang, Meiqin; Liu, Xinglin; Wang, Zhibin; Wang, Gao; Jia, Pinggang</p> <p>2017-03-09</p> <p>A high-sensitivity, low-cost, ultrathin, hollow fiber micro <span class="hlt">bubble</span> structure was proposed; such a <span class="hlt">bubble</span> can be used to develop a high-sensitivity strain sensor based on a Fabry-Perot interferometer (FPI). The micro <span class="hlt">bubble</span> is fabricated at the fiber tip by splicing a glass tube to a single mode fiber (SMF) and then the glass tube is filled with gas in order to expand and form a micro <span class="hlt">bubble</span>. The sensitivity of the strain sensor with a cavity length of about 155 μm and a <span class="hlt">bubble</span> wall thickness of about 6 μm was measured to be up to 8.14 pm/μϵ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27649206','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27649206"><span>Research on the Conductivity-Based Detection Principles of <span class="hlt">Bubbles</span> in Two-Phase Flows and the Design of a <span class="hlt">Bubble</span> Sensor for CBM Wells.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming</p> <p>2016-09-17</p> <p>The parameters of gas-liquid two-phase flow <span class="hlt">bubbles</span> in field coalbed methane (CBM) wells are of great significance for analyzing coalbed methane output, judging faults in CBM wells, and developing gas drainage and extraction processes, which stimulates an urgent need for detecting <span class="hlt">bubble</span> parameters for CBM wells in the field. However, existing <span class="hlt">bubble</span> detectors cannot meet the requirements of the working environments of CBM wells. Therefore, this paper reports findings on the principles of measuring the flow pattern, velocity, and volume of two-phase flow <span class="hlt">bubbles</span> based on conductivity, from which a new <span class="hlt">bubble</span> sensor was designed. The structural parameters and other parameters of the sensor were then computed, the "water film phenomenon" produced by the sensor was analyzed, and the appropriate materials for making the sensor were tested and selected. After the sensor was successfully devised, laboratory tests and field tests were performed, and the test results indicated that the sensor was highly reliable and could detect the flow patterns of two-phase flows, as well as the quantities, velocities, and volumes of <span class="hlt">bubbles</span>. With a velocity measurement error of ±5% and a volume measurement error of ±7%, the sensor can meet the requirements of field use. Finally, the <span class="hlt">characteristics</span> and deficiencies of the <span class="hlt">bubble</span> sensor are summarized based on an analysis of the measurement errors and a comparison of existing <span class="hlt">bubble</span>-measuring devices and the designed sensor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5038793','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5038793"><span>Research on the Conductivity-Based Detection Principles of <span class="hlt">Bubbles</span> in Two-Phase Flows and the Design of a <span class="hlt">Bubble</span> Sensor for CBM Wells</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming</p> <p>2016-01-01</p> <p>The parameters of gas-liquid two-phase flow <span class="hlt">bubbles</span> in field coalbed methane (CBM) wells are of great significance for analyzing coalbed methane output, judging faults in CBM wells, and developing gas drainage and extraction processes, which stimulates an urgent need for detecting <span class="hlt">bubble</span> parameters for CBM wells in the field. However, existing <span class="hlt">bubble</span> detectors cannot meet the requirements of the working environments of CBM wells. Therefore, this paper reports findings on the principles of measuring the flow pattern, velocity, and volume of two-phase flow <span class="hlt">bubbles</span> based on conductivity, from which a new <span class="hlt">bubble</span> sensor was designed. The structural parameters and other parameters of the sensor were then computed, the “water film phenomenon” produced by the sensor was analyzed, and the appropriate materials for making the sensor were tested and selected. After the sensor was successfully devised, laboratory tests and field tests were performed, and the test results indicated that the sensor was highly reliable and could detect the flow patterns of two-phase flows, as well as the quantities, velocities, and volumes of <span class="hlt">bubbles</span>. With a velocity measurement error of ±5% and a volume measurement error of ±7%, the sensor can meet the requirements of field use. Finally, the <span class="hlt">characteristics</span> and deficiencies of the <span class="hlt">bubble</span> sensor are summarized based on an analysis of the measurement errors and a comparison of existing <span class="hlt">bubble</span>-measuring devices and the designed sensor. PMID:27649206</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JHyDy..30...79S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JHyDy..30...79S"><span>Modeling of single film <span class="hlt">bubble</span> and numerical study of the plateau structure in foam system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Zhong-guo; Ni, Ni; Sun, Yi-jie; Xi, Guang</p> <p>2018-02-01</p> <p>The single-film <span class="hlt">bubble</span> has a special geometry with a certain amount of gas shrouded by a thin layer of liquid film under the surface tension force both on the inside and outside surfaces of the <span class="hlt">bubble</span>. Based on the mesh-less moving particle semi-implicit (MPS) method, a single-film double-gas-liquid-interface surface tension (SDST) model is established for the single-film <span class="hlt">bubble</span>, which <span class="hlt">characteristically</span> has totally two gas-liquid interfaces on both sides of the film. Within this framework, the conventional surface free energy surface tension model is improved by using a higher order potential energy equation between particles, and the modification results in higher accuracy and better symmetry properties. The complex interface movement in the oscillation process of the single-film <span class="hlt">bubble</span> is numerically captured, as well as typical flow phenomena and deformation <span class="hlt">characteristics</span> of the liquid film. In addition, the basic behaviors of the coalescence and connection process between two and even three single-film <span class="hlt">bubbles</span> are studied, and the cases with <span class="hlt">bubbles</span> of different sizes are also included. Furthermore, the classic plateau structure in the foam system is reproduced and numerically proved to be in the steady state for multi-<span class="hlt">bubble</span> connections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22492644-cavitation-inception-backscattering-pressure-waves-from-bubble-interface','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22492644-cavitation-inception-backscattering-pressure-waves-from-bubble-interface"><span>Cavitation inception by the backscattering of pressure waves from a <span class="hlt">bubble</span> interface</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Takahira, Hiroyuki, E-mail: takahira@me.osakafu-u.ac.jp; Ogasawara, Toshiyuki, E-mail: oga@me.osakafu-u.ac.jp; Mori, Naoto, E-mail: su101064@edu.osakafu-u.ac.jp</p> <p>2015-10-28</p> <p>The secondary cavitation that occurs by the backscattering of focused ultrasound from a primary cavitation <span class="hlt">bubble</span> caused by the negative pressure part of the ultrasound (Maxwell, et al., 2011) might be useful for the energy exchange due to <span class="hlt">bubble</span> oscillations in High Intensity Focused Ultrasound (HIFU). The present study is concerned with the cavitation inception by the backscattering of ultrasound from a <span class="hlt">bubble</span>. In the present experiment, a laser-induced <span class="hlt">bubble</span> which is generated by a pulsed focused laser beam with high intensity is utilized as a primary cavitation <span class="hlt">bubble</span>. After generating the <span class="hlt">bubble</span>, focused ultrasound is emitted to the <span class="hlt">bubble</span>.more » The acoustic field and the <span class="hlt">bubble</span> motion are observed with a high-speed video camera. It is confirmed that the secondary cavitation <span class="hlt">bubble</span> clouds are generated by the backscattering from the laser-induced <span class="hlt">bubble</span>. The growth of cavitation <span class="hlt">bubble</span> clouds is analyzed with the image processing method. The experimental results show that the height and width of the <span class="hlt">bubble</span> clouds grow in stepwise during their evolution. The direct numerical simulations are also conducted for the backscattering of incident pressure waves from a <span class="hlt">bubble</span> in order to evaluate a pressure field near the <span class="hlt">bubble</span>. It is shown that the ratio of a <span class="hlt">bubble</span> collapse time t{sub 0} to a <span class="hlt">characteristic</span> time of wave propagation t{sub S}, η = t{sub 0}/t{sub s}, is an important determinant for generating negative pressure region by backscattering. The minimum pressure location by the backscattering in simulations is in good agreement with the experiment.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990053987&hterms=Velcro+effect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DVelcro%2Beffect','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990053987&hterms=Velcro+effect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DVelcro%2Beffect"><span>Bursting <span class="hlt">Bubbles</span> from Combustion of Thermoplastic Materials in Microgravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Butler, K. B.</p> <p>1999-01-01</p> <p>Many thermoplastic materials in common use for a wide range of applications, including spacecraft, develop <span class="hlt">bubbles</span> internally as they burn due to chemical reactions taking place within the bulk. These <span class="hlt">bubbles</span> grow and migrate until they burst at the surface, forceably ejecting volatile gases and, occasionally, molten fuel. In experiments in normal gravity, Kashiwagi and Ohlemiller observed vapor jets extending a few centimeters from the surface of a radiatively heated polymethylmethacrylate (PMMA) sample, with some molten material ejected into the gas phase. These physical phenomena complicated the combustion process considerably. In addition to the non-steady release of volatiles, the depth of the surface layer affected by oxygen was increased, attributed to the roughening of the surface by bursting events. The ejection of burning droplets in random directions presents a potential fire hazard unique to microgravity. In microgravity combustion experiments on nylon Velcro fasteners and on polyethylene wire insulation, the presence of bursting fuel vapor <span class="hlt">bubbles</span> was associated with the ejection of small particles of molten fuel as well as pulsations of the flame. For the nylon fasteners, particle velocities were higher than 30 cm/sec. The droplets burned robustly until all fuel was consumed, demonstrating the potential for the spread of fire in random directions over an extended distance. The sequence of events for a bursting <span class="hlt">bubble</span> has been photographed by Newitt et al.. As the <span class="hlt">bubble</span> reaches the fluid surface, the outer surface forms a dome while the internal <span class="hlt">bubble</span> pressure maintains a depression at the inner interface. Liquid drains from the dome until it breaks into a cloud of droplets on the order of a few microns in size. The <span class="hlt">bubble</span> gases are released rapidly, generating vortices in the quiescent surroundings and transporting the tiny droplets. The depression left by the escaping gases collapses into a central jet, which <span class="hlt">rises</span> with a high velocity and may</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12942960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12942960"><span><span class="hlt">Bubble</span> levitation and translation under single-<span class="hlt">bubble</span> sonoluminescence conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Matula, Thomas J</p> <p>2003-08-01</p> <p><span class="hlt">Bubble</span> levitation in an acoustic standing wave is re-examined for conditions relevant to single-<span class="hlt">bubble</span> sonoluminescence. Unlike a previous examination [Matula et al., J. Acoust. Soc. Am. 102, 1522-1527 (1997)], the stable parameter space [Pa,R0] is accounted for in this realization. Forces such as the added mass force and drag are included, and the results are compared with a simple force balance that equates the Bjerknes force to the buoyancy force. Under normal sonoluminescence conditions, the comparison is quite favorable. A more complete accounting of the forces shows that a stably levitated <span class="hlt">bubble</span> does undergo periodic translational motion. The asymmetries associated with translational motion are hypothesized to generate instabilities in the spherical shape of the <span class="hlt">bubble</span>. A reduction in gravity results in reduced translational motion. It is hypothesized that such conditions may lead to increased light output from sonoluminescing <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhFl...30e1904O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhFl...30e1904O"><span>Cavitation <span class="hlt">bubble</span> nucleation induced by shock-<span class="hlt">bubble</span> interaction in a gelatin gel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oguri, Ryota; Ando, Keita</p> <p>2018-05-01</p> <p>An optical visualization technique is developed to study cavitation <span class="hlt">bubble</span> nucleation that results from interaction between a laser-induced shock and a preexisting gas <span class="hlt">bubble</span> in a 10 wt. % gelatin gel; images of the nucleated cavitation <span class="hlt">bubbles</span> are captured and the cavitation inception pressure is determined based on Euler flow simulation. A spherical gas cavity is generated by focusing an infrared laser pulse into a gas-supersaturated gel and the size of the laser-generated <span class="hlt">bubble</span> in mechanical equilibrium is tuned via mass transfer of the dissolved gas into the <span class="hlt">bubble</span>. A spherical shock is then generated, through rapid expansion of plasma induced by the laser focusing, in the vicinity of the gas <span class="hlt">bubble</span>. The shock-<span class="hlt">bubble</span> interaction is recorded by a CCD camera with flash illumination of a nanosecond green laser pulse. The observation captures cavitation inception in the gel under tension that results from acoustic impedance mismatching at the <span class="hlt">bubble</span> interface interacting with the shock. We measure the probability of cavitation inception from a series of the repeated experiments, by varying the <span class="hlt">bubble</span> radius and the standoff distance. The threshold pressure is defined at the cavitation inception probability equal to one half and is calculated, through comparisons to Euler flow simulation, at -24.4 MPa. This threshold value is similar to that from shock-<span class="hlt">bubble</span> interaction experiments using water, meaning that viscoelasticity of the 10 wt. % gelatin gel has a limited impact on <span class="hlt">bubble</span> nucleation dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020016466&hterms=Evolution+MORE+evidence+gravity&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DEvolution%2BMORE%2Bevidence%2Bgravity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020016466&hterms=Evolution+MORE+evidence+gravity&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DEvolution%2BMORE%2Bevidence%2Bgravity"><span>Dynamics of Vapour <span class="hlt">Bubbles</span> in Nucleate Boiling. 2; Evolution of Thermally Controlled <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Buyevich, Yu A.; Webbon, Bruce W.; Callaway, Robert (Technical Monitor)</p> <p>1995-01-01</p> <p>The previously developed dynamic theory of growth and detachment of vapour <span class="hlt">bubbles</span> under conditions of nucleate pool boiling is applied to study motion and deformation of a <span class="hlt">bubble</span> evolving at a single nucleation site. The <span class="hlt">bubble</span> growth is presumed to be thermally controlled, and two components of heat transfer to the <span class="hlt">bubble</span> are accounted of: the one from the bulk of surrounding liquid and the one due to heat conduction across a liquid microlayer formed underneath the <span class="hlt">bubble</span>. <span class="hlt">Bubble</span> evolution is governed by the buoyancy and an effective surface tension force, both the forces making the <span class="hlt">bubble</span> centre of mass move away from the wall and, thus, assisting its detachment. Buoyancy-controlled and surface-tension-controlled regimes are considered separately in a meticulous way. The duration of the whole process of <span class="hlt">bubble</span> evolution till detachment, the rate of growth, and the <span class="hlt">bubble</span> departure size are found as functions of time and physical and operating parameters. Some repeatedly observed phenomena, such as an influence of gravity on the growth rate, are explained. Inferences of the model agree qualitatively with available experimental evidence, and conclusions pertaining to the dependence on gravity of the <span class="hlt">bubble</span> radius at detachment and the whole time of the <span class="hlt">bubble</span> development when being attached to the wall are confirmed quantitatively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900015975','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900015975"><span>A computational efficient modelling of laminar separation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dini, Paolo; Maughmer, Mark D.</p> <p>1990-01-01</p> <p>In predicting the aerodynamic <span class="hlt">characteristics</span> of airfoils operating at low Reynolds numbers, it is often important to account for the effects of laminar (transitional) separation <span class="hlt">bubbles</span>. Previous approaches to the modelling of this viscous phenomenon range from fast but sometimes unreliable empirical correlations for the length of the <span class="hlt">bubble</span> and the associated increase in momentum thickness, to more accurate but significantly slower displacement-thickness iteration methods employing inverse boundary-layer formulations in the separated regions. Since the penalty in computational time associated with the more general methods is unacceptable for airfoil design applications, use of an accurate yet computationally efficient model is highly desirable. To this end, a semi-empirical <span class="hlt">bubble</span> model was developed and incorporated into the Eppler and Somers airfoil design and analysis program. The generality and the efficiency was achieved by successfully approximating the local viscous/inviscid interaction, the transition location, and the turbulent reattachment process within the framework of an integral boundary-layer method. Comparisons of the predicted aerodynamic <span class="hlt">characteristics</span> with experimental measurements for several airfoils show excellent and consistent agreement for Reynolds numbers from 2,000,000 down to 100,000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JSV...420...61D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JSV...420...61D"><span>Natural oscillations of a gas <span class="hlt">bubble</span> in a liquid-filled cavity located in a viscoelastic medium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Doinikov, Alexander A.; Marmottant, Philippe</p> <p>2018-04-01</p> <p>The present study is motivated by cavitation phenomena that occur in the stems of trees. The internal pressure in tree conduits can drop down to significant negative values. This drop gives <span class="hlt">rise</span> to cavitation <span class="hlt">bubbles</span>, which undergo high-frequency eigenmodes. The aim of the present study is to determine the parameters of the <span class="hlt">bubble</span> natural oscillations. To this end, a theory is developed that describes the pulsation of a spherical <span class="hlt">bubble</span> located at the center of a spherical cavity surrounded by an infinite solid medium. It is assumed that the medium inside the <span class="hlt">bubble</span> is a gas-vapor mixture, the cavity is filled with a compressible viscous liquid, and the medium surrounding the cavity behaves as a viscoelastic solid. The theoretical solution takes into account the outgoing acoustic wave produced by the <span class="hlt">bubble</span> pulsation, the incoming wave caused by reflection from the liquid-solid boundary, and the outgoing wave propagating in the solid. A dispersion equation for the calculation of complex wavenumbers of the <span class="hlt">bubble</span> eigenmodes is derived. Approximate analytical solutions to the dispersion equation are found. Numerical simulations are performed to reveal the effect of different physical parameters on the resonance frequency and the attenuation coefficient of the <span class="hlt">bubble</span> oscillations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27851796','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27851796"><span>Comparison of Monetary Policy Actions and Central Bank Communication on Tackling Asset Price <span class="hlt">Bubbles</span>-Evidence from China's Stock Market.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Ou; Liu, Zhixin</p> <p>2016-01-01</p> <p>We examine the different effects of monetary policy actions and central bank communication on China's stock market <span class="hlt">bubbles</span> with a Time-varying Parameter SVAR model. We find that with negative responses of fundamental component and positive responses of <span class="hlt">bubble</span> component of asset prices, contractionary monetary policy induces the observed stock prices to <span class="hlt">rise</span> during periods of large <span class="hlt">bubbles</span>. By contrast, central bank communication acts on the market through expectation guidance and has more significant effects on stock prices in the long run, which implies that central bank communication be used as an effective long-term instrument for the central bank's policymaking.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29160610','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29160610"><span>Do pregnancy <span class="hlt">characteristics</span> contribute to <span class="hlt">rising</span> childhood cancer incidence rates in the United States?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kehm, Rebecca D; Osypuk, Theresa L; Poynter, Jenny N; Vock, David M; Spector, Logan G</p> <p>2018-03-01</p> <p>Since 1975, childhood cancer incidence rates have gradually increased in the United States; however, few studies have conducted analyses across time to unpack this temporal <span class="hlt">rise</span>. The aim of this study was to test the hypothesis that increasing cancer incidence rates are due to secular trends in pregnancy <span class="hlt">characteristics</span> that are established risk factors for childhood cancer incidence including older maternal age, higher birthweight, and lower birth order. We also considered temporal trends in sociodemographic <span class="hlt">characteristics</span> including race/ethnicity and poverty. We conducted a time series county-level ecologic analysis using linked population-based data from Surveillance, Epidemiology, and End Results cancer registries (1975-2013), birth data from the National Center for Health Statistics (1970-2013), and sociodemographic data from the US Census (1970-2010). We estimated unadjusted and adjusted average annual percent changes (AAPCs) in incidence of combined (all diagnoses) and individual types of cancer among children, ages 0-4 years, from Poisson mixed models. There was a statistically significant unadjusted temporal <span class="hlt">rise</span> in incidence of combined childhood cancers (AAPC = 0.71%; 95% CI = 0.55-0.86), acute lymphoblastic leukemia (0.78%; 0.49-1.07), acute myeloid leukemia (1.86%; 1.13-2.59), central nervous system tumors (1.31%; 0.94-1.67), and hepatoblastoma (2.70%; 1.68-3.72). Adjustment for county-level maternal age reduced estimated AAPCs between 8% (hepatoblastoma) and 55% (combined). However, adjustment for other county <span class="hlt">characteristics</span> did not attenuate AAPCs, and AAPCs remained significantly above 0% in models fully adjusted for county-level <span class="hlt">characteristics</span>. Although <span class="hlt">rising</span> maternal age may account for some of the increase in childhood cancer incidence over time, other factors, not considered in this analysis, may also contribute to temporal trends. © 2017 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA115837','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA115837"><span><span class="hlt">Bubble</span> Dynamics and Resulting Noise from Traveling <span class="hlt">Bubble</span> Cavitation.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1982-04-13</p> <p>proportional to the gas content. The subjectivity of visual cavitation determination is evidenced by the maximum standard deviation. As mentioned before...<span class="hlt">bubble</span> radii at the maximum radius position on the model. The point on the model where the <span class="hlt">bubble</span> will be at its maximum volume was determined by...48 3.7 Recording <span class="hlt">Bubble</span> Dynamics . • . * . . . . 52 3.8 Measurement of Gas Nuclei in Water 0 • 52 3 TABLE OF CONTENTS (continued) Paqe</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhRvE..81a6308L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhRvE..81a6308L"><span>Nonspherical laser-induced cavitation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lim, Kang Yuan; Quinto-Su, Pedro A.; Klaseboer, Evert; Khoo, Boo Cheong; Venugopalan, Vasan; Ohl, Claus-Dieter</p> <p>2010-01-01</p> <p>The generation of arbitrarily shaped nonspherical laser-induced cavitation <span class="hlt">bubbles</span> is demonstrated with a optical technique. The nonspherical <span class="hlt">bubbles</span> are formed using laser intensity patterns shaped by a spatial light modulator using linear absorption inside a liquid gap with a thickness of 40μm . In particular we demonstrate the dynamics of elliptic, toroidal, square, and V-shaped <span class="hlt">bubbles</span>. The <span class="hlt">bubble</span> dynamics is recorded with a high-speed camera at framing rates of up to 300000 frames per second. The observed <span class="hlt">bubble</span> evolution is compared to predictions from an axisymmetric boundary element simulation which provides good qualitative agreement. Interesting dynamic features that are observed in both the experiment and simulation include the inversion of the major and minor axis for elliptical <span class="hlt">bubbles</span>, the rotation of the shape for square <span class="hlt">bubbles</span>, and the formation of a unidirectional jet for V-shaped <span class="hlt">bubbles</span>. Further we demonstrate that specific <span class="hlt">bubble</span> shapes can either be formed directly through the intensity distribution of a single laser focus, or indirectly using secondary <span class="hlt">bubbles</span> that either confine the central <span class="hlt">bubble</span> or coalesce with the main <span class="hlt">bubble</span>. The former approach provides the ability to generate in principle any complex <span class="hlt">bubble</span> geometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JMMM..451..660W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JMMM..451..660W"><span>Magnetic <span class="hlt">bubbles</span> and domain evolution in Fe/Gd multilayer nanodots</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, T. T.; Liu, W.; Dai, Z. M.; Zhao, X. T.; Zhao, X. G.; Zhang, Z. D.</p> <p>2018-04-01</p> <p>The formation of magnetic <span class="hlt">bubbles</span> and the domain-evolution processes, induced by a perpendicular magnetic field in Fe/Gd multilayer films and nanodots, have been investigated. At room temperature, the stripe domains in a continuous film transform into magnetic <span class="hlt">bubbles</span> in an external field, while <span class="hlt">bubbles</span> form spontaneously in nanodots due to the existence of shape anisotropy. When the temperature decreases to 20 K, the enhancement of the perpendicular magnetic anisotropy of the samples results in an increase of the domain size in the continuous film and the magnetization-reversal behavior of each nanodot becomes independent, and most reversed dots do not depend on each other, indicating the magnetic <span class="hlt">characteristics</span> of a single domain. The present research provides further understanding of the evolution of magnetic <span class="hlt">bubbles</span> in the Fe/Gd system and suggests their promising applications in patterned recording materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AIPC.1359..427K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AIPC.1359..427K"><span>The dynamics of histotripsy <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kreider, Wayne; Bailey, Michael R.; Sapozhnikov, Oleg A.; Khokhlova, Vera A.; Crum, Lawrence A.</p> <p>2011-09-01</p> <p>Histotripsy describes treatments in which high-amplitude acoustic pulses are used to excite <span class="hlt">bubbles</span> and erode tissue. Though tissue erosion can be directly attributed to <span class="hlt">bubble</span> activity, the genesis and dynamics of <span class="hlt">bubbles</span> remain unclear. Histotripsy lesions that show no signs of thermal coagulative damage have been generated with two different acoustic protocols: relatively long acoustic pulses that produce local boiling within milliseconds and relatively short pulses that are higher in amplitude but likely do not produce boiling. While these two approaches are often distinguished as `boiling' versus `cavitation', such labels can obscure similarities. In both cases, a <span class="hlt">bubble</span> undergoes large changes in radius and vapor is transported into and out of the <span class="hlt">bubble</span> as it oscillates. Moreover, observations from both approaches suggest that <span class="hlt">bubbles</span> grow to a size at which they cease to collapse violently. In order to better understand the dynamics of histotripsy <span class="hlt">bubbles</span>, a single-<span class="hlt">bubble</span> model has been developed that couples acoustically excited <span class="hlt">bubble</span> motions to the thermodynamic state of the surrounding liquid. Using this model for <span class="hlt">bubbles</span> exposed to histotripsy sound fields, simulations suggest that two mechanisms can act separately or in concert to lead to the typically observed <span class="hlt">bubble</span> growth. First, nonlinear acoustic propagation leads to the evolution of shocks and an asymmetry in the positive and negative pressures that drive <span class="hlt">bubble</span> motion. This asymmetry can have a rectifying effect on <span class="hlt">bubble</span> oscillations whereby the <span class="hlt">bubble</span> grows on average during each acoustic cycle. Second, vapor transport to/from the <span class="hlt">bubble</span> tends to produce larger <span class="hlt">bubbles</span>, especially at elevated temperatures. Vapor transport by itself can lead to rectified <span class="hlt">bubble</span> growth when the ambient temperature exceeds 100 °C (`boiling') or local heating in the vicinity of the <span class="hlt">bubble</span> leads to a superheated boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhDT........28V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhDT........28V"><span>Analytical and numerical investigations of <span class="hlt">bubble</span> behavior in electric fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vorreiter, Janelle Orae</p> <p></p> <p>The behavior of gas <span class="hlt">bubbles</span> in liquids is important in a wide range of applications. This study is motivated by a desire to understand the motion of <span class="hlt">bubbles</span> in the absence of gravity, as in many aerospace applications. Phase-change devices, cryogenic tanks and life-support systems are some of the applications where <span class="hlt">bubbles</span> exist in space environments. One of the main difficulties in employing devices with <span class="hlt">bubbles</span> in zero gravity environments is the absence of a buoyancy force. The use of an electric field is found to be an effective means of replacing the buoyancy force, improving the control of <span class="hlt">bubbles</span> in space environments. In this study, analytical and numerical investigations of <span class="hlt">bubble</span> behavior under the influence of electric fields are performed. The problem is a difficult one in that the physics of the liquid and the electric field need to be considered simultaneously to model the dynamics of the <span class="hlt">bubble</span>. Simplifications are required to reduce the problem to a tractable form. In this work, for the liquid and the electric field, assumptions are made which reduce the problem to one requiring only the solution of potentials in the domain of interest. Analytical models are developed using a perturbation analysis applicable for small deviations from a spherical shape. Numerical investigations are performed using a boundary integral code. A number of configurations are found to be successful in promoting <span class="hlt">bubble</span> motion by varying properties of the electric fields. In one configuration, the natural frequencies of a <span class="hlt">bubble</span> are excited using time-varying electric and pressure fields. The applied electric field is spatially uniform with frequencies corresponding to shape modes of the <span class="hlt">bubble</span>. The resulting <span class="hlt">bubble</span> velocity is related to the strength of the electric field as well as the <span class="hlt">characteristics</span> of the applied fields. In another configuration, static non-uniform fields are used to encourage <span class="hlt">bubble</span> motion. The resulting motion is related to the degree of non</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22364588-fermi-bubbles-bubble-like-emission-from-galactic-plane','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22364588-fermi-bubbles-bubble-like-emission-from-galactic-plane"><span>FERMI <span class="hlt">BUBBLES</span> AND <span class="hlt">BUBBLE</span>-LIKE EMISSION FROM THE GALACTIC PLANE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>De Boer, Wim; Weber, Markus, E-mail: wim.de.boer@kit.edu, E-mail: markus.weber2@kit.edu</p> <p>2014-10-10</p> <p>The diffuse gamma-ray sky revealed ''<span class="hlt">bubbles</span>'' of emission above and below the Galactic plane, symmetric around the center of the Milky Way, with a height of 10 kpc in both directions. At present, there is no convincing explanation for the origin. To understand the role of the Galactic center, one has to study the <span class="hlt">bubble</span> spectrum inside the disk, a region that has been excluded from previous analyses because of the large foreground. From a novel template fit, which allows a simultaneous determination of the signal and foreground in any direction, we find that <span class="hlt">bubble</span>-like emission is not only found inmore » the halo, but in the Galactic plane as well, with a width in latitude coinciding with the molecular clouds. The longitude distribution has a width corresponding to the Galactic bar with an additional contribution from the Scutum-Centaurus arm. The energy spectrum of the <span class="hlt">bubbles</span> coincides with the predicted contribution from CRs trapped in sources (SCRs). Also, the energetics fits well. Hence, we conclude that the <span class="hlt">bubble</span>-like emission has a hadronic origin that arises from SCRs, and the <span class="hlt">bubbles</span> in the halo arise from hadronic interactions in advected gas. Evidence for advection is provided by the ROSAT X-rays of hot gas in the <span class="hlt">bubble</span> region.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApPhL.103a4103A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApPhL.103a4103A"><span>Electrowetting of soap <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arscott, Steve</p> <p>2013-07-01</p> <p>A proof-of-concept demonstration of the electrowetting-on-dielectric of a sessile soap <span class="hlt">bubble</span> is reported here. The <span class="hlt">bubbles</span> are generated using a commercial soap <span class="hlt">bubble</span> mixture—the surfaces are composed of highly doped, commercial silicon wafers covered with nanometer thick films of Teflon®. Voltages less than 40 V are sufficient to observe the modification of the <span class="hlt">bubble</span> shape and the apparent <span class="hlt">bubble</span> contact angle. Such observations open the way to inter alia the possibility of <span class="hlt">bubble</span>-transport, as opposed to droplet-transport, in fluidic microsystems (e.g., laboratory-on-a-chip)—the potential gains in terms of volume, speed, and surface/volume ratio are non-negligible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5108003','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5108003"><span>Optical coherence tomography <span class="hlt">characteristics</span> of different types of big <span class="hlt">bubbles</span> seen in deep anterior lamellar keratoplasty by the big <span class="hlt">bubble</span> technique</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>AlTaan, S L; Termote, K; Elalfy, M S; Hogan, E; Werkmeister, R; Schmetterer, L; Holland, S; Dua, H S</p> <p>2016-01-01</p> <p>Purpose To define optical coherence tomography (OCT) <span class="hlt">characteristics</span> of type-1, type-2, and mixed big <span class="hlt">bubbles</span> (BB) seen in deep anterior lamellar keratoplasty. Methods Human sclero-corneal discs were obtained from UK (30) and Canada (16) eye banks. Air was injected into corneal stroma until a BB formed. UK samples were fixed in formalin before scanning with Fourier-domain (FD-OCT). One pair of each type of BB was scanned fresh. All BB obtained from Canada were scanned fresh with time-domain (TD-OCT). For each OCT machine used, type-1 BB from which Descemets membrane (DM) was partially peeled, were also scanned. The morphological <span class="hlt">characteristics</span> of the scans were studied. Results FD-OCT of the posterior wall of type-1 (Dua's layer (DL) with DM) and type-2 BB (DM alone) both revealed a double-contour hyper-reflective curvilinear image with a hypo-reflective zone in between. The anterior line of type-2 BB was thinner than that seen with type-1 BB. In mixed BB, FD-OCT showed two separate curvilinear images. The anterior image was a single hyper-reflective line (DL), whereas the posterior image, representing the posterior wall of type-2 BB (DM) was made of two hyper-reflective lines with a dark space in between. TD-OCT images were similar with less defined component lines, but the entire extent of the BB could be visualised. Conclusion On OCT examination the DM and DL present distinct features, which can help identify type-1, type-2, and mixed BB. These <span class="hlt">characteristics</span> will help corneal surgeons interpret intraoperative OCT during lamellar corneal surgery. PMID:27472215</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..MARR26006W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..MARR26006W"><span>Hexagonal <span class="hlt">bubble</span> formation and nucleation in sodium chloride solution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Lifen; Liu, Lei; Mohsin, Ali; Wen, Jianguo; Gu, Gong; Miller, Dean</p> <p></p> <p>The <span class="hlt">bubble</span> is formed frequently at a solid-liquid interface when the surface of the solid or liquid has a tendency of accumulating molecular species due to unbalanced surface hydrophobicity attraction. Morphology and shape of the <span class="hlt">bubble</span> are thought to be associated with the Laplace pressure that spherical-cap-shaped object are commonly observed. Dynamic surface nanobubble formation and nucleation in the controlled system have been not fully investigated due to the direct visualization challenge in liquid systems. Here, utilizing in situ TEM, dynamic formation and collapse of spherical-shaped nanobubbles were observed at the water-graphene interface, while hexagonal nanobubbles grew and merged with each other at water-crystalline sodium chloride interface. Our finding demonstrates that different hydrophobic-hydrophilic interaction systems give <span class="hlt">rise</span> to the varied morphology of surface nanobubble, leading to the fundamental understanding of the interface-interaction-governed law on the formation of surface nanobubble.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51D2091L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51D2091L"><span>Simulating <span class="hlt">Bubble</span> Plumes from Breaking Waves with a Forced-Air Venturi</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Long, M. S.; Keene, W. C.; Maben, J. R.; Chang, R. Y. W.; Duplessis, P.; Kieber, D. J.; Beaupre, S. R.; Frossard, A. A.; Kinsey, J. D.; Zhu, Y.; Lu, X.; Bisgrove, J.</p> <p>2017-12-01</p> <p>It has been hypothesized that the size distribution of <span class="hlt">bubbles</span> in subsurface seawater is a major factor that modulates the corresponding size distribution of primary marine aerosol (PMA) generated when those <span class="hlt">bubbles</span> burst at the air-water interface. A primary physical control of the <span class="hlt">bubble</span> size distribution produced by wave breaking is the associated turbulence that disintegrates larger <span class="hlt">bubbles</span> into smaller ones. This leads to two <span class="hlt">characteristic</span> features of <span class="hlt">bubble</span> size distributions: (1) the Hinze scale which reflects a <span class="hlt">bubble</span> size above which disintegration is possible based on turbulence intensity and (2) the slopes of log-linear regressions of the size distribution on either side of the Hinze scale that indicate the state of plume evolution or age. A Venturi with tunable seawater and forced air flow rates was designed and deployed in an artificial PMA generator to produce <span class="hlt">bubble</span> plumes representative of breaking waves. This approach provides direct control of turbulence intensity and, thus, the resulting <span class="hlt">bubble</span> size distribution characterizable by observations of the Hinze scale and the simulated plume age over a range of known air detrainment rates. Evaluation of performance in different seawater types over the western North Atlantic demonstrated that the Venturi produced <span class="hlt">bubble</span> plumes with parameter values that bracket the range of those observed in laboratory and field experiments. Specifically, the seawater flow rate modulated the value of the Hinze scale while the forced-air flow rate modulated the plume age parameters. Results indicate that the size distribution of sub-surface <span class="hlt">bubbles</span> within the generator did not significantly modulate the corresponding number size distribution of PMA produced via <span class="hlt">bubble</span> bursting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10250E..24L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10250E..24L"><span>Investigation of the properties of laser-induced cavitation <span class="hlt">bubble</span> collapse and sound waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Shengyong; Ai, Xiaochuan; Wu, Ronghua; Cao, Jing</p> <p>2017-02-01</p> <p>The theoretical model of single <span class="hlt">bubble</span> movement in an ideal solution, to carry on the numerical simulation of the process of cavitation in the liquid, the liquid in different laser energy, laser induced cavitation rules and acoustic <span class="hlt">characteristics</span> were studied by high-speed camera, high frequency measurements of the hydrophone. The results show that with the increase of laser energy, the period of <span class="hlt">bubble</span> pulsation and the maximum <span class="hlt">bubble</span> radius increase gradually, and the amplitude of the laser acoustic signal becomes larger.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26690168','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26690168"><span>The <span class="hlt">Bubble</span> Box: Towards an Automated Visual Sensor for 3D Analysis and Characterization of Marine Gas Release Sites.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jordt, Anne; Zelenka, Claudius; von Deimling, Jens Schneider; Koch, Reinhard; Köser, Kevin</p> <p>2015-12-05</p> <p>Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for <span class="hlt">bubble</span> stream observation have become an important tool, as they help estimating flux and <span class="hlt">bubble</span> sizes under certain assumptions. However, they record only a projection of a <span class="hlt">bubble</span> into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical <span class="hlt">bubbles</span>. The unknown distance of the <span class="hlt">bubble</span> to the camera (making it appear larger or smaller than expected) as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor <span class="hlt">bubble</span> box that overcomes these limitations, as it observes <span class="hlt">bubbles</span> from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting that are crucial to arrive at a 3D ellipsoidal shape and <span class="hlt">rise</span> speed of each <span class="hlt">bubble</span>. The obtained values for single <span class="hlt">bubbles</span> can be aggregated into statistical <span class="hlt">bubble</span> size distributions or fluxes for extrapolation based on diffusion and dissolution models and large scale acoustic surveys. We demonstrate and evaluate the wide baseline stereo measurement model using a controlled test setup with ground truth information.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4721745','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4721745"><span>The <span class="hlt">Bubble</span> Box: Towards an Automated Visual Sensor for 3D Analysis and Characterization of Marine Gas Release Sites</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jordt, Anne; Zelenka, Claudius; Schneider von Deimling, Jens; Koch, Reinhard; Köser, Kevin</p> <p>2015-01-01</p> <p>Several acoustic and optical techniques have been used for characterizing natural and anthropogenic gas leaks (carbon dioxide, methane) from the ocean floor. Here, single-camera based methods for <span class="hlt">bubble</span> stream observation have become an important tool, as they help estimating flux and <span class="hlt">bubble</span> sizes under certain assumptions. However, they record only a projection of a <span class="hlt">bubble</span> into the camera and therefore cannot capture the full 3D shape, which is particularly important for larger, non-spherical <span class="hlt">bubbles</span>. The unknown distance of the <span class="hlt">bubble</span> to the camera (making it appear larger or smaller than expected) as well as refraction at the camera interface introduce extra uncertainties. In this article, we introduce our wide baseline stereo-camera deep-sea sensor <span class="hlt">bubble</span> box that overcomes these limitations, as it observes <span class="hlt">bubbles</span> from two orthogonal directions using calibrated cameras. Besides the setup and the hardware of the system, we discuss appropriate calibration and the different automated processing steps deblurring, detection, tracking, and 3D fitting that are crucial to arrive at a 3D ellipsoidal shape and <span class="hlt">rise</span> speed of each <span class="hlt">bubble</span>. The obtained values for single <span class="hlt">bubbles</span> can be aggregated into statistical <span class="hlt">bubble</span> size distributions or fluxes for extrapolation based on diffusion and dissolution models and large scale acoustic surveys. We demonstrate and evaluate the wide baseline stereo measurement model using a controlled test setup with ground truth information. PMID:26690168</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AIPC..728..180L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AIPC..728..180L"><span>Nonlinear <span class="hlt">Bubble</span> Dynamics And The Effects On Propagation Through Near-Surface <span class="hlt">Bubble</span> Layers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leighton, Timothy G.</p> <p>2004-11-01</p> <p>Nonlinear <span class="hlt">bubble</span> dynamics are often viewed as the unfortunate consequence of having to use high acoustic pressure amplitudes when the void fraction in the near-surface oceanic <span class="hlt">bubble</span> layer is great enough to cause severe attenuation (e.g. >50 dB/m). This is seen as unfortunate since existing models for acoustic propagation in <span class="hlt">bubbly</span> liquids are based on linear <span class="hlt">bubble</span> dynamics. However, the development of nonlinear models does more than just allow quantification of the errors associated with the use of linear models. It also offers the possibility of propagation modeling and acoustic inversions which appropriately incorporate the <span class="hlt">bubble</span> nonlinearity. Furthermore, it allows exploration and quantification of possible nonlinear effects which may be exploited. As a result, high acoustic pressure amplitudes may be desirable even in low void fractions, because they offer opportunities to gain information about the <span class="hlt">bubble</span> cloud from the nonlinearities, and options to exploit the nonlinearities to enhance communication and sonar in <span class="hlt">bubbly</span> waters. This paper presents a method for calculating the nonlinear acoustic cross-sections, scatter, attenuations and sound speeds from <span class="hlt">bubble</span> clouds which may be inhomogeneous. The method allows prediction of the time dependency of these quantities, both because the cloud may vary and because the incident acoustic pulse may have finite and arbitrary time history. The method can be readily adapted for <span class="hlt">bubbles</span> in other environments (e.g. clouds of interacting <span class="hlt">bubbles</span>, sediments, structures, in vivo, reverberant conditions etc.). The possible exploitation of <span class="hlt">bubble</span> acoustics by marine mammals, and for sonar enhancement, is explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29131810','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29131810"><span>The role of trapped <span class="hlt">bubbles</span> in kidney stone detection with the color Doppler ultrasound twinkling artifact.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Simon, Julianna C; Sapozhnikov, Oleg A; Kreider, Wayne; Breshock, Michael; Williams, James C; Bailey, Michael R</p> <p>2018-01-09</p> <p>The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice <span class="hlt">bubbles</span> on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the <span class="hlt">bubbles</span> have not been directly observed. In this paper, the micron or submicron-sized <span class="hlt">bubbles</span> predicted by the crevice <span class="hlt">bubble</span> hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some <span class="hlt">bubbles</span> to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice <span class="hlt">bubbles</span>. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging <span class="hlt">bubbles</span>, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice <span class="hlt">bubble</span> hypothesis of twinkling and suggest the kidney stone crevices that give <span class="hlt">rise</span> to the twinkling phenomenon may be internal as well as external.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PMB....63b5011S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PMB....63b5011S"><span>The role of trapped <span class="hlt">bubbles</span> in kidney stone detection with the color Doppler ultrasound twinkling artifact</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simon, Julianna C.; Sapozhnikov, Oleg A.; Kreider, Wayne; Breshock, Michael; Williams, James C., Jr.; Bailey, Michael R.</p> <p>2018-01-01</p> <p>The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice <span class="hlt">bubbles</span> on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the <span class="hlt">bubbles</span> have not been directly observed. In this paper, the micron or submicron-sized <span class="hlt">bubbles</span> predicted by the crevice <span class="hlt">bubble</span> hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some <span class="hlt">bubbles</span> to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice <span class="hlt">bubbles</span>. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging <span class="hlt">bubbles</span>, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice <span class="hlt">bubble</span> hypothesis of twinkling and suggest the kidney stone crevices that give <span class="hlt">rise</span> to the twinkling phenomenon may be internal as well as external.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830062067&hterms=dissolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddissolution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830062067&hterms=dissolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddissolution"><span>Preliminary study of the effects of a reversible chemical reaction on gas <span class="hlt">bubble</span> dissolution. [for space glass refining</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weinberg, M. C.</p> <p>1982-01-01</p> <p>A preliminary investigation is carried out of the effects of a reversible chemical reaction on the dissolution of an isolated, stationary gas <span class="hlt">bubble</span> in a glass melt. The exact governing equations for the model system are formulated and analyzed. The approximate quasi-steady-state version of these equations is solved analytically, and a calculation is made of <span class="hlt">bubble</span> dissolution rates. The results are then compared with numerical solutions obtained from the finite difference form of the exact governing equations. It is pointed out that in the microgravity condition of space, the buoyant <span class="hlt">rise</span> of a gas <span class="hlt">bubble</span> in a glass melt will be negligible on the time scale of most experiments. For this reason, a determination of the behavior of a stationary gas <span class="hlt">bubble</span> in a melt is relevant for an understanding of glass refining in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhFl...30d1701K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhFl...30d1701K"><span>Letter: Entrapment and interaction of an air <span class="hlt">bubble</span> with an oscillating cavitation <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kannan, Y. S.; Karri, Badarinath; Sahu, Kirti Chandra</p> <p>2018-04-01</p> <p>The mechanism of the formation of an air <span class="hlt">bubble</span> due to an oscillating cavitation <span class="hlt">bubble</span> in its vicinity is reported from an experimental study using high-speed imaging. The cavitation <span class="hlt">bubble</span> is created close to the free surface of water using a low-voltage spark circuit comprising two copper electrodes in contact with each other. Before the <span class="hlt">bubble</span> is created, a third copper wire is positioned in contact with the free surface of water close to the two crossing electrodes. Due to the surface tension at the triple point (wire-water-air) interface, a small dip is observed in the free surface at the point where the wire is immersed. When the cavitation <span class="hlt">bubble</span> is created, the <span class="hlt">bubble</span> pushes at the dip while expanding and pulls at it while collapsing. The collapse phase leads to the entrapment of an air <span class="hlt">bubble</span> at the wire immersion point. During this phase, the air <span class="hlt">bubble</span> undergoes a "catapult" effect, i.e., it expands to a maximum size and then collapses with a microjet at the free surface. To the best of our knowledge, this mechanism has not been reported so far. A parametric study is also conducted to understand the effects of wire orientation and <span class="hlt">bubble</span> distance from the free surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1348074','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1348074"><span>Computational Fluid Dynamics Modeling of <span class="hlt">Bubbling</span> in a Viscous Fluid for Validation of Waste Glass Melter Modeling</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Abboud, Alexander William; Guillen, Donna Post</p> <p>2016-01-01</p> <p>At the Hanford site, radioactive waste stored in underground tanks is slated for vitrification for final disposal. A comprehensive knowledge of the glass batch melting process will be useful in optimizing the process, which could potentially reduce the cost and duration of this multi-billion dollar cleanup effort. We are developing a high-fidelity heat transfer model of a Joule-heated ceramic lined melter to improve the understanding of the complex, inter-related processes occurring with the melter. The glass conversion rates in the cold cap layer are dependent on promoting efficient heat transfer. In practice, heat transfer is augmented by inserting air bubblersmore » into the molten glass. However, the computational simulations must be validated to provide confidence in the solutions. As part of a larger validation procedure, it is beneficial to split the physics of the melter into smaller systems to validate individually. The substitution of molten glass for a simulant liquid with similar density and viscosity at room temperature provides a way to study mixing through <span class="hlt">bubbling</span> as an isolated effect without considering the heat transfer dynamics. The simulation results are compared to experimental data obtained by the Vitreous State Laboratory at the Catholic University of America using bubblers placed within a large acrylic tank that is similar in scale to a pilot glass waste melter. Comparisons are made for surface area of the <span class="hlt">rising</span> air <span class="hlt">bubbles</span> between experiments and CFD simulations for a variety of air flow rates and <span class="hlt">bubble</span> injection depths. Also, computed <span class="hlt">bubble</span> <span class="hlt">rise</span> velocity is compared to a well-accepted expression for <span class="hlt">bubble</span> terminal velocity.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110020420','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110020420"><span><span class="hlt">Bubble</span> Eliminator Based on Centrifugal Flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gonda, Steve R.; Tsao, Yow-Min D.; Lee, Wenshan</p> <p>2004-01-01</p> <p>The fluid <span class="hlt">bubble</span> eliminator (FBE) is a device that removes gas <span class="hlt">bubbles</span> from a flowing liquid. The FBE contains no moving parts and does not require any power input beyond that needed to pump the liquid. In the FBE, the buoyant force for separating the gas from the liquid is provided by a radial pressure gradient associated with a centrifugal flow of the liquid and any entrained <span class="hlt">bubbles</span>. A device based on a similar principle is described in Centrifugal Adsorption Cartridge System (MSC- 22863), which appears on page 48 of this issue. The FBE was originally intended for use in filtering <span class="hlt">bubbles</span> out of a liquid flowing relatively slowly in a bioreactor system in microgravity. Versions that operate in normal Earth gravitation at greater flow speeds may also be feasible. The FBE (see figure) is constructed as a cartridge that includes two concentric cylinders with flanges at the ends. The outer cylinder is an impermeable housing; the inner cylinder comprises a gas-permeable, liquid-impermeable membrane covering a perforated inner tube. Multiple spiral disks that collectively constitute a spiral ramp are mounted in the space between the inner and outer cylinders. The liquid enters the FBE through an end flange, flows in the annular space between the cylinders, and leaves through the opposite end flange. The spiral disks channel the liquid into a spiral flow, the circumferential component of which gives <span class="hlt">rise</span> to the desired centrifugal effect. The resulting radial pressure gradient forces the <span class="hlt">bubbles</span> radially inward; that is, toward the inner cylinder. At the inner cylinder, the gas-permeable, liquid-impermeable membrane allows the <span class="hlt">bubbles</span> to enter the perforated inner tube while keeping the liquid in the space between the inner and outer cylinders. The gas thus collected can be vented via an endflange connection to the inner tube. The centripetal acceleration (and thus the radial pressure gradient) is approximately proportional to the square of the flow speed and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/article/002762.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/article/002762.htm"><span><span class="hlt">Bubble</span> bath soap poisoning</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... medlineplus.gov/ency/article/002762.htm <span class="hlt">Bubble</span> bath soap poisoning To use the sharing features on this page, please enable JavaScript. <span class="hlt">Bubble</span> bath soap poisoning occurs when someone swallows <span class="hlt">bubble</span> bath soap. ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22410083-characteristics-temperature-rise-variable-inductor-employing-magnetorheological-fluid-driven-high-frequency-pulsed-voltage-source','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22410083-characteristics-temperature-rise-variable-inductor-employing-magnetorheological-fluid-driven-high-frequency-pulsed-voltage-source"><span><span class="hlt">Characteristics</span> of temperature <span class="hlt">rise</span> in variable inductor employing magnetorheological fluid driven by a high-frequency pulsed voltage source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lee, Ho-Young; Kang, In Man, E-mail: imkang@ee.knu.ac.kr; Shon, Chae-Hwa</p> <p>2015-05-07</p> <p>A variable inductor with magnetorheological (MR) fluid has been successfully applied to power electronics applications; however, its thermal <span class="hlt">characteristics</span> have not been investigated. To evaluate the performance of the variable inductor with respect to temperature, we measured the <span class="hlt">characteristics</span> of temperature <span class="hlt">rise</span> and developed a numerical analysis technique. The <span class="hlt">characteristics</span> of temperature <span class="hlt">rise</span> were determined experimentally and verified numerically by adopting a multiphysics analysis technique. In order to accurately estimate the temperature distribution in a variable inductor with an MR fluid-gap, the thermal solver should import the heat source from the electromagnetic solver to solve the eddy current problem. Tomore » improve accuracy, the B–H curves of the MR fluid under operating temperature were obtained using the magnetic property measurement system. In addition, the Steinmetz equation was applied to evaluate the core loss in a ferrite core. The predicted temperature <span class="hlt">rise</span> for a variable inductor showed good agreement with the experimental data and the developed numerical technique can be employed to design a variable inductor with a high-frequency pulsed voltage source.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H31L..04K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H31L..04K"><span>Characterization of nano-<span class="hlt">bubbles</span> as an oxygen carrier for in-situ bioremediation of organic pollutants in the subsurface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>KIM, E.; Jung, J.; Kang, S.; Choi, Y.</p> <p>2016-12-01</p> <p>In-situ bioremediation using <span class="hlt">bubbles</span> as an oxygen carrier has shown its applicability for aerobic biodegradation of organic pollutants in the subsurface. By recent progresses, generation of nano-sized <span class="hlt">bubbles</span> is possible, which have enhanced oxygen transfer efficiencies due to their high interfacial area and stability. We are developing an in-situ bioremediation technique using nano-<span class="hlt">bubbles</span> as an oxygen carrier. In this study, nano-<span class="hlt">bubbles</span> were characterized for their size and oxygen supply capacity. Nano-<span class="hlt">bubbles</span> were generated with pure oxygen and pure helium gas. The stable nano-<span class="hlt">bubbles</span> suspended in water were sonicated to induce the <span class="hlt">bubbles</span> to coalesce, making them to <span class="hlt">rise</span> and be released out of the water. By removing the <span class="hlt">bubbles</span>, the water volume was decreased by 0.006%. The gas released from the <span class="hlt">bubble</span> suspension was collected to measure the amount of gas in the nano-<span class="hlt">bubbles</span>. For sparingly soluble helium gas 17.9 mL/L was released from the <span class="hlt">bubble</span> suspension, while for oxygen 46.2 mL/L was collected. For the oxygen nano-<span class="hlt">bubble</span> suspension, it is likely that the release of dissolved oxygen (DO) contributed to the collected gas volume. After removing the oxygen nano-<span class="hlt">bubbles</span>, 36.0 mg/L of DO was still present in water. Altogether, the oxygen nano-<span class="hlt">bubble</span> suspension was estimated to have 66.2 mg/L of oxygen in a dissolved form and 25.6 mg/L as nano-<span class="hlt">bubbles</span>. A high DO level in the water was possible because of their large Laplace pressure difference across the fluid interface. Applying Young-Laplace equation and ideal gas law, the <span class="hlt">bubble</span> diameter was estimated to be approximately 10 nm, having an internal pressure of 323 atm. Considering the saturation DO of 8.26 mg/L for water in equilibrium with the atmosphere, the total oxygen content of 91.8 mg/L in the nano-<span class="hlt">bubble</span> suspension suggests its great potential as an oxygen carrier. Studies are underway to verify the enhanced aerobic biodegradation of organic pollutants in soils by injecting nano-<span class="hlt">bubble</span> suspensions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDH21004A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDH21004A"><span>Visualization of airflow growing soap <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Al Rahbi, Hamood; Bock, Matthew; Ryu, Sangjin</p> <p>2016-11-01</p> <p>Visualizing airflow inside growing soap <span class="hlt">bubbles</span> can answer questions regarding the fluid dynamics of soap <span class="hlt">bubble</span> blowing, which is a model system for flows with a gas-liquid-gas interface. Also, understanding the soap <span class="hlt">bubble</span> blowing process is practical because it can contribute to controlling industrial processes similar to soap <span class="hlt">bubble</span> blowing. In this study, we visualized airflow which grows soap <span class="hlt">bubbles</span> using the smoke wire technique to understand how airflow blows soap <span class="hlt">bubbles</span>. The soap <span class="hlt">bubble</span> blower setup was built to mimic the human blowing process of soap <span class="hlt">bubbles</span>, which consists of a blower, a nozzle and a <span class="hlt">bubble</span> ring. The smoke wire was placed between the nozzle and the <span class="hlt">bubble</span> ring, and smoke-visualized airflow was captured using a high speed camera. Our visualization shows how air jet flows into the growing soap <span class="hlt">bubble</span> on the ring and how the airflow interacts with the soap film of growing <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940009275','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940009275"><span>Study of <span class="hlt">bubble</span> behavior in weightlessness (effects of thermal gradient and acoustic stationary wave) (M-16)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Azuma, H.</p> <p>1993-01-01</p> <p>The aim of this experiment is to understand how <span class="hlt">bubbles</span> behave in a thermal gradient and acoustic stationary wave under microgravity. In microgravity, <span class="hlt">bubble</span> or <span class="hlt">bubbles</span> in a liquid will not <span class="hlt">rise</span> upward as they do on Earth but will rest where they are formed because there exists no gravity-induced buoyancy. We are interested in how <span class="hlt">bubbles</span> move and in the mechanisms which support the movement. We will try two ways to make <span class="hlt">bubbles</span> migrate. The first experiment concerns behavior of <span class="hlt">bubbles</span> in a thermal gradient. It is well known than an effect of surface tension which is masked by gravity on the ground becomes dominant in microgravity. The surface tension on the side of the <span class="hlt">bubble</span> at a lower temperature is stronger than at a higher temperature. The <span class="hlt">bubble</span> migrates toward the higher temperature side due to the surface tension difference. The migration speed depends on the so-called Marangoni number, which is a function of the temperature difference, the <span class="hlt">bubble</span> diameter, liquid viscosity, and thermal diffusivity. At present, some experimental data about migration speeds in liquids with very small Marangoni numbers were obtained in space experiments, but cases of large Marangoni number are rarely obtained. In our experiment a couple of <span class="hlt">bubbles</span> are to be injected into a cell filled with silicon oil, and the temperature gradient is to be made gradually in the cell by a heater and a cooler. We will be able to determine migration speeds in a very wide range of Marangoni numbers, as well as study interactions between the <span class="hlt">bubbles</span>. We will observe <span class="hlt">bubble</span> movements affected by hydrodynamical and thermal interactions, the two kinds of interactions which occur simultaneously. These observation data will be useful for analyzing the interactions as well as understanding the behavior of particles or drops in materials processing. The second experiment concerns <span class="hlt">bubble</span> movement in an acoustic stationary wave. It is known that a <span class="hlt">bubble</span> in a stationary wave moves toward the node or the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28633816','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28633816"><span>A derivation of the stable cavitation threshold accounting for <span class="hlt">bubble-bubble</span> interactions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guédra, Matthieu; Cornu, Corentin; Inserra, Claude</p> <p>2017-09-01</p> <p>The subharmonic emission of sound coming from the nonlinear response of a <span class="hlt">bubble</span> population is the most used indicator for stable cavitation. When driven at twice their resonance frequency, <span class="hlt">bubbles</span> can exhibit subharmonic spherical oscillations if the acoustic pressure amplitude exceeds a threshold value. Although various theoretical derivations exist for the subharmonic emission by free or coated <span class="hlt">bubbles</span>, they all rest on the single <span class="hlt">bubble</span> model. In this paper, we propose an analytical expression of the subharmonic threshold for interacting <span class="hlt">bubbles</span> in a homogeneous, monodisperse cloud. This theory predicts a shift of the subharmonic resonance frequency and a decrease of the corresponding pressure threshold due to the interactions. For a given sonication frequency, these results show that an optimal value of the interaction strength (i.e. the number density of <span class="hlt">bubbles</span>) can be found for which the subharmonic threshold is minimum, which is consistent with recently published experiments conducted on ultrasound contrast agents. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120003981','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120003981"><span>Analysis of the Pressure <span class="hlt">Rise</span> in a Partially Filled Liquid Tank in Microgravity with Low Wall Heat Flux and Simultaneous Boiling and Condensation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hasan, Mohammad M.; Balasubramaniam, R.</p> <p>2012-01-01</p> <p>Experiments performed with Freon 113 in the space shuttle have shown that in a pro- cess of very slow heating, high liquid superheats can be sustained for a long period in microgravity. In a closed system explosive vaporization of superheated liquid resulted in pressure spikes of varying magnitudes. In this paper, we analyze the pressure <span class="hlt">rise</span> in a partially lled closed tank in which a large vapor <span class="hlt">bubble</span> (i.e., ullage) is initially present, and the liquid is subjected to a low wall heat ux. The liquid layer adjacent to the wall becomes superheated until the temperature for nucleation of the <span class="hlt">bubbles</span> (or the incipience of boiling) is achieved. In the absence of the gravity-induced convection large quantities of superheated liquid can accumulate over time near the heated surface. Once the incipience temperature is attained, explosive boiling occurs and the vapor <span class="hlt">bubbles</span> that are produced on the heater surface tend to quickly raise the tank pressure. The liquid-vapor saturation temperature increases as well. These two e ects tend to induce condensation of the large ullage <span class="hlt">bubble</span> that is initially present, and tends to mitigate the tank pressure <span class="hlt">rise</span>. As a result, the tank pressure is predicted to <span class="hlt">rise</span> sharply, attain a maximum, and subsequently decay slowly. The predicted pressure <span class="hlt">rise</span> is compared with experimental results obtained in the microgravity environments of the space shuttle for Freon 113. The analysis is appli- cable, in general to heating of liquid in closed containers in microgravity and to cryogenic fuel tanks, in particular where small heat leaks into the tank are unavoidable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010004342','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010004342"><span>Single <span class="hlt">Bubble</span> Sonoluminescence in Low Gravity and Optical Radiation Pressure Positioning of the <span class="hlt">Bubble</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thiessen, D. B.; Young, J. E.; Marr-Lyon, M. J.; Richardson, S. L.; Breckon, C. D.; Douthit, S. G.; Jian, P. S.; Torruellas, W. E.; Marston, P. L.</p> <p>1999-01-01</p> <p>Several groups of researchers have demonstrated that high frequency sound in water may be used to cause the regular repeated compression and luminescence of a small <span class="hlt">bubble</span> of gas in a flask. The phenomenon is known as single <span class="hlt">bubble</span> sonoluminescence (SBSL). It is potentially important because light emitted by the <span class="hlt">bubble</span> appears to be associated with a significant concentration of energy within the volume of the <span class="hlt">bubble</span>. Unfortunately, the detailed physical mechanisms causing the radiation of light by oscillating <span class="hlt">bubbles</span> are poorly understood and there is some evidence that carrying out experiments in a weightless environment may provide helpful clues. In addition, the radiation pressure of laser beams on the <span class="hlt">bubble</span> may provide a way of simulating weightless experiments in the laboratory. The standard model of SBSL attributes the light emission to heating within the <span class="hlt">bubble</span> by a spherically imploding shock wave to achieve temperatures of 50,000 K or greater. In an alternative model, the emission is attributed to the impact of a jet of water which is required to span the <span class="hlt">bubble</span> and the formation of the jet is linked to the buoyancy of the <span class="hlt">bubble</span>. The coupling between buoyancy and jet formation is a consequence of the displacement of the <span class="hlt">bubble</span> from a velocity node (pressure antinode) of the standing acoustic wave that drives the radial <span class="hlt">bubble</span> oscillations. One objective of this grant is to understand SBSL emission in reduced buoyancy on KC-135 parabolic flights. To optimize the design of those experiments and for other reasons which will help resolve the role of buoyancy, laboratory experiments are planned in simulated low gravity in which the radiation pressure of laser light will be used to position the <span class="hlt">bubble</span> at the acoustic velocity node of the ultrasonic standing wave. Laser light will also be used to push the <span class="hlt">bubble</span> away from the velocity node, increasing the effective buoyancy. The original experiments on the optical levitation and radiation pressure on <span class="hlt">bubbles</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998ApJ...492..804E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998ApJ...492..804E"><span>The Physics of Twisted Magnetic Tubes <span class="hlt">Rising</span> in a Stratified Medium: Two-dimensional Results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Emonet, T.; Moreno-Insertis, F.</p> <p>1998-01-01</p> <p>The physics of a twisted magnetic flux tube <span class="hlt">rising</span> in a stratified medium is studied using a numerical magnetohydrodynamic (MHD) code. The problem considered is fully compressible (has no Boussinesq approximation), includes ohmic resistivity, and is two-dimensional, i.e., there is no variation of the variables in the direction of the tube axis. We study a high-plasma β-case with a small ratio of radius to external pressure scale height. The results obtained will therefore be of relevance to understanding the transport of magnetic flux across the solar convection zone. We confirm that a sufficient twist of the field lines around the tube axis can suppress the conversion of the tube into two vortex rolls. For a tube with a relative density deficit on the order of 1/β (the classical Parker buoyancy) and a radius smaller than the pressure scale height (R2<<H2p), the minimum amount of twist necessary corresponds to an average pitch angle on the order of sin-1 [(R/Hp)1/2]. The evolution of a tube with this degree of twist is studied in detail, including the initial transient phase, the internal torsional oscillations, and the asymptotic, quasi-stationary phase. During the initial phase, the outermost, weakly magnetized layers of the tube are torn off its main body and endowed with vorticity. They yield a trailing magnetized wake with two vortex rolls. The fraction of the total magnetic flux that is brought to the wake is a function of the initial degree of twist. In the weakly twisted case, most of the initial tube is turned into vortex rolls. With a strong initial twist, the tube <span class="hlt">rises</span> with only a small deformation and no substantial loss of magnetic flux. The formation of the wake and the loss of flux from the main body of the tube are basically complete after the initial transient phase. A sharp interface between the tube interior and the external flows is formed at the tube front and sides; this area has the <span class="hlt">characteristic</span> features of a magnetic boundary layer. Its</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/350971','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/350971"><span>Aspherical <span class="hlt">bubble</span> dynamics and oscillation times</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Godwin, R.P.; Chapyak, E.J.; Noack, J.</p> <p>1999-03-01</p> <p>The cavitation <span class="hlt">bubbles</span> common in laser medicine are rarely perfectly spherical and are often located near tissue boundaries, in vessels, etc., which introduce aspherical dynamics. Here, novel features of aspherical <span class="hlt">bubble</span> dynamics are explored. Time-resolved experimental photographs and simulations of large aspect ratio (length:diameter {approximately}20) cylindrical <span class="hlt">bubble</span> dynamics are presented. The experiments and calculations exhibit similar dynamics. A small high-pressure cylindrical <span class="hlt">bubble</span> initially expands radially with hardly any axial motion. Then, after reaching its maximum volume, a cylindrical <span class="hlt">bubble</span> collapses along its long axis with relatively little radial motion. The growth-collapse period of these very aspherical <span class="hlt">bubbles</span> differs only sightlymore » from twice the Rayleigh collapse time for a spherical <span class="hlt">bubble</span> with an equivalent maximum volume. This fact justifies using the temporal interval between the acoustic signals emitted upon <span class="hlt">bubble</span> creation and collapse to estimate the maximum <span class="hlt">bubble</span> volume. As a result, hydrophone measurements can provide an estimate of the <span class="hlt">bubble</span> energy even for aspherical <span class="hlt">bubbles</span>. The prolongation of the oscillation period of <span class="hlt">bubbles</span> near solid boundaries relative to that of isolated spherical <span class="hlt">bubbles</span> is also discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15890380','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15890380"><span><span class="hlt">Bubble</span> oscillation and inertial cavitation in viscoelastic fluids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiménez-Fernández, J; Crespo, A</p> <p>2005-08-01</p> <p>Non-linear acoustic oscillations of gas <span class="hlt">bubbles</span> immersed in viscoelastic fluids are theoretically studied. The problem is formulated by considering a constitutive equation of differential type with an interpolated time derivative. With the aid of this rheological model, fluid elasticity, shear thinning viscosity and extensional viscosity effects may be taken into account. <span class="hlt">Bubble</span> radius evolution in time is analyzed and it is found that the amplitude of the <span class="hlt">bubble</span> oscillations grows drastically as the Deborah number (the ratio between the relaxation time of the fluid and the <span class="hlt">characteristic</span> time of the flow) increases, so that, even for moderate values of the external pressure amplitude, the behavior may become chaotic. The quantitative influence of the rheological fluid properties on the pressure thresholds for inertial cavitation is investigated. Pressure thresholds values in terms of the Deborah number for systems of interest in ultrasonic biomedical applications, are provided. It is found that these critical pressure amplitudes are clearly reduced as the Deborah number is increased.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000031620','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000031620"><span>System for Manipulating Drops and <span class="hlt">Bubbles</span> Using Acoustic Radiation Pressure</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oeftering, Richard C. (Inventor)</p> <p>1999-01-01</p> <p>The manipulation and control of drops of liquid and gas <span class="hlt">bubbles</span> is achieved using high intensity acoustics in the form of and/or acoustic radiation pressure and acoustic streaming. generated by a controlled wave emission from a transducer. Acoustic radiation pressure is used to deploy or dispense drops into a liquid or a gas or <span class="hlt">bubbles</span> into a liquid at zero or near zero velocity from the discharge end of a needle such as a syringe needle. Acoustic streaming is useful in manipulating the drop or <span class="hlt">bubble</span> during or after deployment. Deployment and discharge is achieved by focusing the acoustic radiation pressure on the discharge end of the needle, and passing the acoustic waves through the fluid in the needle. through the needle will itself, or coaxially through the fluid medium surrounding the needle. Alternatively, the acoustic waves can be counter-deployed by focusing on the discharge end of the needle from a transducer axially aligned with the needle, but at a position opposite the needle, to prevent premature deployment of the drop or <span class="hlt">bubble</span>. The acoustic radiation pressure can also be used for detecting the presence or absence of a drop or a <span class="hlt">bubble</span> at the tip of a needle or for sensing various physical <span class="hlt">characteristics</span> of the drop or <span class="hlt">bubble</span> such as size or density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDM35010S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDM35010S"><span>From <span class="hlt">bubble</span> bursting to droplet evaporation in the context of champagne aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seon, Thomas; Ghabache, Elisabeth; Antkowiak, Arnaud; Liger-Belair, Gerard</p> <p>2015-11-01</p> <p>As champagne or sparkling wine is poured into a glass, a myriad of ascending <span class="hlt">bubbles</span> collapse and therefore radiate a multitude of tiny droplets above the free surface into the form of very <span class="hlt">characteristic</span> and refreshing aerosols. Because these aerosols have been found to hold the organoleptic ``essence'' of champagne they are believed to play a crucial role in the flavor release in comparison with that from a flat wine for example. Based on the model experiment of a single <span class="hlt">bubble</span> bursting in idealized champagnes, the velocity, radius and maximum height of the first jet drop following <span class="hlt">bubble</span> collapse have been characterized, with varying <span class="hlt">bubble</span> size and liquid properties in the context of champagne aerosols. Using the experimental results and simple theoretical models for drop and surface evaporation, we show that <span class="hlt">bubble</span> bursting aerosols drastically enhance the transfer of liquid in the atmosphere with respect to a flat liquid surface. Contrary to popular opinion, we exhibit that small <span class="hlt">bubbles</span> are negative in terms of aroma release, and we underline <span class="hlt">bubble</span> radii enabling to optimize the droplet height and evaporation in the whole range of champagne properties. These results pave the road to the fine tuning of champagne aroma diffusion, a major issue of the sparkling wine industry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002APS..DFD.CA002P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002APS..DFD.CA002P"><span><span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prosperetti, Andrea</p> <p>2002-11-01</p> <p>``Vanitas vanitatum et omnia vanitas": <span class="hlt">bubbles</span> are emptiness, non-liquid, a tiny cloud shielding a mathematical singularity. Born from chance, a violent and brief life ending in the union with the (nearly) infinite. But a wealth of phenomena spring forth from this nothingness: underwater noise, sonoluminescence, boiling, many others. Ultimately, diffusive processes govern much of the physics, and the difference between the diffusivity of heat and dissolved gases in ordinary liquids holds the key to the striking differences between gas and vapor <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ASSP...34..371S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ASSP...34..371S"><span>Fermi <span class="hlt">Bubble</span>: Giant Gamma-Ray <span class="hlt">Bubbles</span> in the Milky Way</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Meng</p> <p></p> <p>Data from the Fermi-LAT reveal two gigantic gamma-ray emitting <span class="hlt">bubble</span> structures (known as the Fermibubbles), extending˜50° above and below the Galactic center symmetric about the Galactic plane, with a width of˜40∘ in longitude. The gamma-ray emission associated with these <span class="hlt">bubbles</span> has a significantly harder spectrum ({dN}/{dE} ˜ {E}^{-2}) than the inverse Compton emission from known cosmic ray electrons in the Galactic disk, or the gamma-rays produced by decay of pions from proton-ISM collisions. The <span class="hlt">bubbles</span> are spatially correlated with the hard-spectrum microwave excess known as the WMAPhaze; the edges of the <span class="hlt">bubbles</span> also line up with features in the ROSATsoft X-ray maps at 1.5-2keV. The Fermibubble is most likely created by some large episode of energy injection in the Galactic center, such as past accretion events onto the central massive black hole, or a nuclear starburst in the last˜10Myr. Study of the origin and evolution of the <span class="hlt">bubbles</span> also has the potential to improve our understanding of recent energetic events in the inner Galaxy and the high-latitude cosmic ray population.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080007051','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080007051"><span><span class="hlt">Bubble</span> measuring instrument and method</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Magari, Patrick J. (Inventor); Kline-Schoder, Robert (Inventor)</p> <p>2003-01-01</p> <p>Method and apparatus are provided for a non-invasive <span class="hlt">bubble</span> measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as <span class="hlt">bubbles</span> over a selectable range of <span class="hlt">bubble</span> sizes of interest. A selected measurement volume in which <span class="hlt">bubbles</span> may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer, respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite <span class="hlt">bubbles</span> to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which <span class="hlt">bubbles</span> may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant <span class="hlt">bubble</span>. In a preferred embodiment, software control maintains the beat signal at a preselected frequency while varying the pump transducer frequency to excite <span class="hlt">bubbles</span> of different diameters to resonate depending on the range of <span class="hlt">bubble</span> diameters selected for investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020078061','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020078061"><span><span class="hlt">Bubble</span> Measuring Instrument and Method</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kline-Schoder, Robert (Inventor); Magari, Patrick J. (Inventor)</p> <p>2002-01-01</p> <p>Method and apparatus are provided for a non-invasive <span class="hlt">bubble</span> measuring instrument operable for detecting, distinguishing, and counting gaseous embolisms such as <span class="hlt">bubbles</span> over a selectable range of <span class="hlt">bubble</span> sizes of interest. A selected measurement volume in which <span class="hlt">bubbles</span> may be detected is insonified by two distinct frequencies from a pump transducer and an image transducer. respectively. The image transducer frequency is much higher than the pump transducer frequency. The relatively low-frequency pump signal is used to excite <span class="hlt">bubbles</span> to resonate at a frequency related to their diameter. The image transducer is operated in a pulse-echo mode at a controllable repetition rate that transmits bursts of high-frequency ultrasonic signal to the measurement volume in which <span class="hlt">bubbles</span> may be detected and then receives the echo. From the echo or received signal, a beat signal related to the repetition rate may be extracted and used to indicate the presence or absence of a resonant <span class="hlt">bubble</span>. In a preferred embodiment, software control maintains the beat signal at a preselected frequency while varying the pump transducer frequency to excite <span class="hlt">bubbles</span> of different diameters to resonate depending on the range of <span class="hlt">bubble</span> diameters selected for investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030005575&hterms=Scholarships&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DScholarships','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030005575&hterms=Scholarships&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DScholarships"><span><span class="hlt">Bubble</span> Formation and Detachment in Reduced Gravity Under the Influence of Electric Fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Herman, Cila; Iacona, Estelle; Chang, Shinan</p> <p>2002-01-01</p> <p>The objective of the study is to investigate the behavior of individual air <span class="hlt">bubbles</span> injected through an orifice into an electrically insulating liquid under the influence of a static electric field. Both uniform and nonuniform electric field configurations were considered. <span class="hlt">Bubble</span> formation and detachment were recorded and visualized in reduced gravity (corresponding to gravity levels on Mars, on the Moon as well as microgravity) using a high-speed video camera. <span class="hlt">Bubble</span> volume, dimensions and contact angle at detachment were measured. In addition to the experimental studies, a simple model, predicting <span class="hlt">bubble</span> <span class="hlt">characteristics</span> at detachment was developed. The model, based on thermodynamic considerations, accounts for the level of gravity as well as the magnitude of the uniform electric field. Measured data and model predictions show good agreement and indicate that the level of gravity and the electric field magnitude significantly affect <span class="hlt">bubble</span> shape, volume and dimensions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19545884','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19545884"><span>Towards classification of the bifurcation structure of a spherical cavitation <span class="hlt">bubble</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Behnia, Sohrab; Sojahrood, Amin Jafari; Soltanpoor, Wiria; Sarkhosh, Leila</p> <p>2009-12-01</p> <p>We focus on a single cavitation <span class="hlt">bubble</span> driven by ultrasound, a system which is a specimen of forced nonlinear oscillators and is characterized by its extreme sensitivity to the initial conditions. The driven radial oscillations of the <span class="hlt">bubble</span> are considered to be implicated by the principles of chaos physics and owing to specific ranges of control parameters, can be periodic or chaotic. Despite the growing number of investigations on its dynamics, there is not yet an inclusive yardstick to sort the dynamical behavior of the <span class="hlt">bubble</span> into classes; also, the response oscillations are so complex that long term prediction on the behavior becomes difficult to accomplish. In this study, the nonlinear dynamics of a <span class="hlt">bubble</span> oscillator was treated numerically and the simulations were proceeded with bifurcation diagrams. The calculated bifurcation diagrams were compared in an attempt to classify the <span class="hlt">bubble</span> dynamic <span class="hlt">characteristics</span> when varying the control parameters. The comparison reveals distinctive bifurcation patterns as a consequence of driving the systems with unequal ratios of R(0)lambda (where R(0) is the <span class="hlt">bubble</span> initial radius and lambda is the wavelength of the driving ultrasonic wave). Results indicated that systems having the equal ratio of R(0)lambda, share remarkable similarities in their bifurcating behavior and can be classified under a unit category.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.B33E2123C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.B33E2123C"><span>Layered storage of biogenic methane-enriched gas <span class="hlt">bubbles</span> in peat: A lumped capacitance model controlled by soil structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, X.; Comas, X.; Binley, A. M.; Slater, L. D.</p> <p>2017-12-01</p> <p>Methane can accumulate in the gaseous phase in peats, and enter the atmosphere as gas <span class="hlt">bubbles</span> with a mass flux higher than that via diffusion and plant-mediated pathways. A complete understanding of the mechanisms regulating <span class="hlt">bubble</span> storage in peats remains incomplete. We developed a layered model to quantify the storage of gas <span class="hlt">bubbles</span> over a peat column based on a general lumped capacitance model. This conceptual model was applied to explain the effects of peat structure on <span class="hlt">bubble</span> storage at different depths observed in a laboratory experiment. A peat monolith was collected from the Everglades, a subtropical wetland located in Florida (USA), and kept submerged in a cuboid chamber over 102 days until gas <span class="hlt">bubble</span> saturation was achieved. Time-lapse ground-penetrating radar (GPR) was used to estimate changes in gas content of each layer and the corresponding average dimensions of stored gas <span class="hlt">bubbles</span>. The results highlight a hotspot layer of <span class="hlt">bubble</span> accumulation at depths between 5 and 10 cm below the monolith surface. <span class="hlt">Bubbles</span> in this shallow hotspot layer were larger relative to those in deeper layers, whilst the degree of decomposition of the upper layers was generally smaller than that of the lower layers based on von Post humification tests. X-ray Computer tomography (CT) was applied to resin-impregnated peat sections from different depths and the results showed that a higher porosity promotes <span class="hlt">bubbles</span> storage. The stored gas <span class="hlt">bubbles</span> were released by changing water levels and the air CH4 concentrations above the peat monolith were measured using a flow-through chamber system to confirm the high CH4 concentration in the stored <span class="hlt">bubbles</span>. Our findings suggest that <span class="hlt">bubble</span> capacitance is related to the difference in size between gas <span class="hlt">bubbles</span> and peat pores. This work has implications for better understanding how changes in water table elevation associated with climate change and sea level <span class="hlt">rise</span> (particularly for freshwater wetlands near coastal areas like the Everglades) may</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18048983','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18048983"><span>Effects of floc and <span class="hlt">bubble</span> size on the efficiency of the dissolved air flotation (DAF) process.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Han, Mooyoung; Kim, Tschung-il; Kim, Jinho</p> <p>2007-01-01</p> <p>Dissolved air flotation (DAF) is a method for removing particles from water using micro <span class="hlt">bubbles</span> instead of settlement. The process has proved to be successful and, since the 1960s, accepted as an alternative to the conventional sedimentation process for water and wastewater treatment. However, limited research into the process, especially the fundamental <span class="hlt">characteristics</span> of <span class="hlt">bubbles</span> and particles, has been carried out. The single collector collision model is not capable of determining the effects of particular <span class="hlt">characteristics</span>, such as the size and surface charge of <span class="hlt">bubbles</span> and particles. Han has published a set of modeling results after calculating the collision efficiency between <span class="hlt">bubbles</span> and particles by trajectory analysis. His major conclusion was that collision efficiency is maximum when the <span class="hlt">bubbles</span> and particles are nearly the same size but have opposite charge. However, experimental verification of this conclusion has not been carried out yet. This paper describes a new method for measuring the size of particles and <span class="hlt">bubbles</span> developed using computational image analysis. DAF efficiency is influenced by the effect of the recycle ratio on various average floc sizes. The larger the recycle ratio, the higher the DAF efficiency at the same pressure and particle size. The treatment efficiency is also affected by the saturation pressure, because the <span class="hlt">bubble</span> size and <span class="hlt">bubble</span> volume concentration are controlled by the pressure. The highest efficiency is obtained when the floc size is larger than the <span class="hlt">bubble</span> size. These results, namely that the highest collision efficiency occurs when the particles and <span class="hlt">bubbles</span> are about the same size, are more in accordance with the trajectory model than with the white water collector model, which implies that the larger the particles, the higher is the collision efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=GL-2002-001196&hterms=eating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Deating','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=GL-2002-001196&hterms=eating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Deating"><span>BLOWING COSMIC <span class="hlt">BUBBLES</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>This NASA Hubble Space Telescope image reveals an expanding shell of glowing gas surrounding a hot, massive star in our Milky Way Galaxy. This shell is being shaped by strong stellar winds of material and radiation produced by the bright star at the left, which is 10 to 20 times more massive than our Sun. These fierce winds are sculpting the surrounding material - composed of gas and dust - into the curve-shaped <span class="hlt">bubble</span>. Astronomers have dubbed it the <span class="hlt">Bubble</span> Nebula (NGC 7635). The nebula is 10 light-years across, more than twice the distance from Earth to the nearest star. Only part of the <span class="hlt">bubble</span> is visible in this image. The glowing gas in the lower right-hand corner is a dense region of material that is getting blasted by radiation from the <span class="hlt">Bubble</span> Nebula's massive star. The radiation is eating into the gas, creating finger-like features. This interaction also heats up the gas, causing it to glow. Scientists study the <span class="hlt">Bubble</span> Nebula to understand how hot stars interact with the surrounding material. Credit: Hubble Heritage Team (AURA/STScI/NASA)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA07841&hterms=baby&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbaby','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA07841&hterms=baby&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbaby"><span>A <span class="hlt">Bubble</span> Bursts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p><p/> RCW 79 is seen in the southern Milky Way, 17,200 light-years from Earth in the constellation Centaurus. The <span class="hlt">bubble</span> is 70-light years in diameter, and probably took about one million years to form from the radiation and winds of hot young stars. <p/> The balloon of gas and dust is an example of stimulated star formation. Such stars are born when the hot <span class="hlt">bubble</span> expands into the interstellar gas and dust around it. RCW 79 has spawned at least two groups of new stars along the edge of the large <span class="hlt">bubble</span>. Some are visible inside the small <span class="hlt">bubble</span> in the lower left corner. Another group of baby stars appears near the opening at the top. <p/> NASA's Spitzer Space Telescope easily detects infrared light from the dust particles in RCW 79. The young stars within RCW 79 radiate ultraviolet light that excites molecules of dust within the <span class="hlt">bubble</span>. This causes the dust grains to emit infrared light that is detected by Spitzer and seen here as the extended red features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JCAP...12..029F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JCAP...12..029F"><span><span class="hlt">Bubble</span> nucleation and inflationary perturbations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Firouzjahi, Hassan; Jazayeri, Sadra; Karami, Asieh; Rostami, Tahereh</p> <p>2017-12-01</p> <p>In this work we study the imprints of <span class="hlt">bubble</span> nucleation on primordial inflationary perturbations. We assume that the <span class="hlt">bubble</span> is formed via the tunneling of a spectator field from the false vacuum of its potential to its true vacuum. We consider the configuration in which the observable CMB sphere is initially outside of the <span class="hlt">bubble</span>. As the <span class="hlt">bubble</span> expands, more and more regions of the exterior false vacuum, including our CMB sphere, fall into the interior of the <span class="hlt">bubble</span>. The modes which leave the horizon during inflation at the time when the <span class="hlt">bubble</span> wall collides with the observable CMB sphere are affected the most. The <span class="hlt">bubble</span> wall induces non-trivial anisotropic and scale dependent corrections in the two point function of the curvature perturbation. The corrections in the curvature perturbation and the diagonal and off-diagonal elements of CMB power spectrum are estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017HMT...tmp..370O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017HMT...tmp..370O"><span>Forced convection in the wakes of impacting and sliding <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Reilly Meehan, R.; Williams, N. P.; Donnelly, B.; Persoons, T.; Nolan, K.; Murray, D. B.</p> <p>2017-09-01</p> <p>Both vapour and gas <span class="hlt">bubbles</span> are known to significantly increase heat transfer rates between a heated surface and the surrounding fluid, even with no phase change. The cooling structures observed are highly temporal, intricate and complex, with a full description of the surface cooling phenomena not yet available. The current study uses high speed infrared thermography to measure the surface temperature and determine the convective heat flux enhancement associated with the interaction of a single air <span class="hlt">bubble</span> with a heated, inclined surface. This process can be discretised into the initial impact, in which enhancement levels in excess of 20 times natural convection are observed, and the subsequent sliding behaviour, with more moderate maximum enhancement levels of 8 times natural convection. In both cases, localised regions of suppressed heat transfer are also observed due to the recirculation of warm fluid displaced from the thermal boundary layer with the surface. The cooling patterns observed herein are consistent with the interaction between an undulating wake containing multiple hairpin vortex loops and the thermal boundary layer that exists under the surface, with the initial nature of this enhancement and suppression dependent on the particular point on its <span class="hlt">rising</span> path at which the <span class="hlt">bubble</span> impacts the surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.A7008K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.A7008K"><span>Single-<span class="hlt">bubble</span> boiling under Earth's and low gravity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khusid, Boris; Elele, Ezinwa; Lei, Qian; Tang, John; Shen, Yueyang</p> <p>2017-11-01</p> <p>Miniaturization of electronic systems in terrestrial and space applications is challenged by a dramatic increase in the power dissipation per unit volume with the occurrence of localized hot spots where the heat flux is much higher than the average. Cooling by forced gas or liquid flow appears insufficient to remove high local heat fluxes. Boiling that involves evaporation of liquid in a hot spot and condensation of vapor in a cold region can remove a significantly larger amount of heat through the latent heat of vaporization than force-flow cooling can carry out. Traditional methods for enhancing boiling heat transfer in terrestrial and space applications focus on removal of <span class="hlt">bubbles</span> from the heating surface. In contrast, we unexpectedly observed a new boiling regime of water under Earth's gravity and low gravity in which a <span class="hlt">bubble</span> was pinned on a small heater up to 270°C and delivered a heat flux up to 1.2 MW/m2 that was as high as the critical heat flux in the classical boiling regime on Earth .Low gravity measurements conducted in parabolic flights in NASA Boeing 727. The heat flux in flight and Earth's experiments was found to <span class="hlt">rise</span> linearly with increasing the heater temperature. We will discuss physical mechanisms underlying heat transfer in single-<span class="hlt">bubble</span> boiling. The work supported by NASA Grants NNX12AM26G and NNX09AK06G.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DFDG11008L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DFDG11008L"><span><span class="hlt">Bubble</span> Transport through Micropillar Arrays</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Kenneth; Savas, Omer</p> <p>2012-11-01</p> <p>In current energy research, artificial photosynthetic devices are being designed to split water and harvest hydrogen gas using energy from the sun. In one such design, hydrogen gas <span class="hlt">bubbles</span> evolve on the catalytic surfaces of arrayed micropillars. If these <span class="hlt">bubbles</span> are not promptly removed from the surface, they can adversely affect gas evolution rates, water flow rates, sunlight capture, and heat management of the system. Therefore, an efficient method of collecting the evolved gas <span class="hlt">bubbles</span> is crucial. Preliminary flow visualization has been conducted of <span class="hlt">bubbles</span> advecting through dense arrays of pillars. <span class="hlt">Bubbles</span> moving through square and hexagonal arrays are tracked, and the results are qualitatively described. Initial attempts to correlate <span class="hlt">bubble</span> motion with relevant lengthscales and forces are also presented. These observations suggest how <span class="hlt">bubble</span> transport within such pillar arrays can be managed, as well as guide subsequent experiments that investigate <span class="hlt">bubble</span> evolution and collection. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080004753','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080004753"><span>Gas <span class="hlt">bubble</span> detector</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mount, Bruce E. (Inventor); Burchfield, David E. (Inventor); Hagey, John M. (Inventor)</p> <p>1995-01-01</p> <p>A gas <span class="hlt">bubble</span> detector having a modulated IR source focused through a bandpass filter onto a venturi, formed in a sample tube, to illuminate the venturi with modulated filtered IR to detect the presence of gas <span class="hlt">bubbles</span> as small as 0.01 cm or about 0.004 in diameter in liquid flowing through the venturi. Means are provided to determine the size of any detected <span class="hlt">bubble</span> and to provide an alarm in the absence of liquid in the sample tube.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020038581','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020038581"><span>Behavior of Rapidly Sheared <span class="hlt">Bubble</span> Suspensions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sangani, A. S.; Kushch, V. I.; Hoffmann, M.; Nahra, H.; Koch, D. L.; Tsang, Y.</p> <p>2002-01-01</p> <p>An experiment to be carried out aboard the International Space Station is described. A suspension consisting of millimeter-sized <span class="hlt">bubbles</span> in water containing some dissolved salt, which prevents <span class="hlt">bubbles</span> from coalescing, will be sheared in a Couette cylindrical cell. Rotation of the outer cylinder will produce centrifugal force which will tend to accumulate the <span class="hlt">bubbles</span> near the inner wall. The shearing will enhance collisions among <span class="hlt">bubbles</span> creating thereby <span class="hlt">bubble</span> phase pressure that will resist the tendency of the <span class="hlt">bubbles</span> to accumulate near the inner wall. The <span class="hlt">bubble</span> volume fraction and velocity profiles will be measured and compared with the theoretical predictions. Ground-based research on measurement of <span class="hlt">bubble</span> phase properties and flow in vertical channel are described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26565252','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26565252"><span>Doughnut-shaped soap <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Préve, Deison; Saa, Alberto</p> <p>2015-10-01</p> <p>Soap <span class="hlt">bubbles</span> are thin liquid films enclosing a fixed volume of air. Since the surface tension is typically assumed to be the only factor responsible for conforming the soap <span class="hlt">bubble</span> shape, the realized <span class="hlt">bubble</span> surfaces are always minimal area ones. Here, we consider the problem of finding the axisymmetric minimal area surface enclosing a fixed volume V and with a fixed equatorial perimeter L. It is well known that the sphere is the solution for V=L(3)/6π(2), and this is indeed the case of a free soap <span class="hlt">bubble</span>, for instance. Surprisingly, we show that for V<αL(3)/6π(2), with α≈0.21, such a surface cannot be the usual lens-shaped surface formed by the juxtaposition of two spherical caps, but is rather a toroidal surface. Practically, a doughnut-shaped <span class="hlt">bubble</span> is known to be ultimately unstable and, hence, it will eventually lose its axisymmetry by breaking apart in smaller <span class="hlt">bubbles</span>. Indisputably, however, the topological transition from spherical to toroidal surfaces is mandatory here for obtaining the global solution for this axisymmetric isoperimetric problem. Our result suggests that deformed <span class="hlt">bubbles</span> with V<αL(3)/6π(2) cannot be stable and should not exist in foams, for instance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..92d2402P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..92d2402P"><span>Doughnut-shaped soap <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Préve, Deison; Saa, Alberto</p> <p>2015-10-01</p> <p>Soap <span class="hlt">bubbles</span> are thin liquid films enclosing a fixed volume of air. Since the surface tension is typically assumed to be the only factor responsible for conforming the soap <span class="hlt">bubble</span> shape, the realized <span class="hlt">bubble</span> surfaces are always minimal area ones. Here, we consider the problem of finding the axisymmetric minimal area surface enclosing a fixed volume V and with a fixed equatorial perimeter L . It is well known that the sphere is the solution for V =L3/6 π2 , and this is indeed the case of a free soap <span class="hlt">bubble</span>, for instance. Surprisingly, we show that for V <α L3/6 π2 , with α ≈0.21 , such a surface cannot be the usual lens-shaped surface formed by the juxtaposition of two spherical caps, but is rather a toroidal surface. Practically, a doughnut-shaped <span class="hlt">bubble</span> is known to be ultimately unstable and, hence, it will eventually lose its axisymmetry by breaking apart in smaller <span class="hlt">bubbles</span>. Indisputably, however, the topological transition from spherical to toroidal surfaces is mandatory here for obtaining the global solution for this axisymmetric isoperimetric problem. Our result suggests that deformed <span class="hlt">bubbles</span> with V <α L3/6 π2 cannot be stable and should not exist in foams, for instance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6975814-bubble-generation-during-transformer-overload','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6975814-bubble-generation-during-transformer-overload"><span><span class="hlt">Bubble</span> generation during transformer overload</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Oommen, T.V.</p> <p>1990-03-01</p> <p><span class="hlt">Bubble</span> generation in transformers has been demonstrated under certain overload conditions. The release of large quantities of <span class="hlt">bubbles</span> would pose a dielectric breakdown hazard. A <span class="hlt">bubble</span> prediction model developed under EPRI Project 1289-4 attempts to predict the <span class="hlt">bubble</span> evolution temperature under different overload conditions. This report details a verification study undertaken to confirm the validity of the above model using coil structures subjected to overload conditions. The test variables included moisture in paper insulation, gas content in oil, and the type of oil preservation system. Two aged coils were also tested. The results indicated that the observed <span class="hlt">bubble</span> temperatures weremore » close to the predicted temperatures for models with low initial gas content in the oil. The predicted temperatures were significantly lower than the observed temperatures for models with high gas content. Some explanations are provided for the anomalous behavior at high gas levels in oil. It is suggested that the dissolved gas content is not a significant factor in <span class="hlt">bubble</span> evolution. The dominant factor in <span class="hlt">bubble</span> evolution appears to be the water vapor pressure which must reach critical levels before <span class="hlt">bubbles</span> can be released. Further study is needed to make a meaningful revision of the <span class="hlt">bubble</span> prediction model. 8 refs., 13 figs., 11 tabs.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......181G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......181G"><span>Pulsed electrical discharge in gas <span class="hlt">bubbles</span> in water</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gershman, Sophia</p> <p></p> <p>A phenomenological picture of pulsed electrical discharge in gas <span class="hlt">bubbles</span> in water is produced by combining electrical, spectroscopic, and imaging methods. The discharge is generated by applying one microsecond long 5 to 20 kilovolt pulses between the needle and disk electrodes submerged in water. A gas <span class="hlt">bubble</span> is generated at the tip of the needle electrode. The study includes detailed experimental investigation of the discharge in argon <span class="hlt">bubbles</span> and a brief look at the discharge in oxygen <span class="hlt">bubbles</span>. Imaging, electrical <span class="hlt">characteristics</span>, and time-resolved optical emission data point to a fast streamer propagation mechanism and formation of a plasma channel in the <span class="hlt">bubble</span>. Spectroscopic methods based on line intensity ratios and Boltzmann plots of line intensities of argon, atomic hydrogen, and argon ions and the examination of molecular emission bands from molecular nitrogen and hydroxyl radicals provide evidence of both fast beam-like electrons and slow thermalized ones with temperatures of 0.6 -- 0.8 electron-volts. The collisional nature of plasma at atmospheric pressure affects the decay rates of optical emission. Spectroscopic study of rotational-vibrational bands of hydroxyl radical and molecular nitrogen gives vibrational and rotational excitation temperatures of the discharge of about 0.9 and 0.1 electron-volt, respectively. Imaging and electrical evidence show that discharge charge is deposited on the <span class="hlt">bubble</span> wall and water serves as a dielectric barrier for the field strength and time scales of this experiment. Comparing the electrical and imaging information for consecutive pulses applied at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from long-lived chemical species, such as ozone and oxygen. Intermediate values for the discharge gap and pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ExFl...58...43K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ExFl...58...43K"><span>Vortex shedding within laminar separation <span class="hlt">bubbles</span> forming over an airfoil</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirk, Thomas M.; Yarusevych, Serhiy</p> <p>2017-05-01</p> <p>Vortex shedding within laminar separation <span class="hlt">bubbles</span> forming over the suction side of a NACA 0018 airfoil is studied through a combination of high-speed flow visualization and boundary layer measurements. Wind tunnel experiments are performed at a chord-based Reynolds number of 100,000 and four angles of attack. The high-speed flow visualization is complemented by quantitative velocity and surface pressure measurements. The structures are shown to originate from the natural amplification of small-amplitude disturbances, and the shear layer roll-up is found to occur coherently across the span. However, significant cycle-to-cycle variations are observed in vortex <span class="hlt">characteristics</span>, including shedding period and roll-up location. The formation of the roll-up vortices precedes the later stages of transition, during which these structures undergo significant deformations and breakdown to smaller scales. During this stage of flow development, vortex merging is also observed. The results provide new insight into the development of coherent structures in separation <span class="hlt">bubbles</span> and their relation to the overall <span class="hlt">bubble</span> dynamics and mean <span class="hlt">bubble</span> topology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.G4006B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.G4006B"><span><span class="hlt">Bubble</span> transport in bifurcations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bull, Joseph; Qamar, Adnan</p> <p>2017-11-01</p> <p>Motivated by a developmental gas embolotherapy technique for cancer treatment, we examine the transport of <span class="hlt">bubbles</span> entrained in liquid. In gas embolotherapy, infarction of tumors is induced by selectively formed vascular gas <span class="hlt">bubbles</span> that originate from acoustic vaporization of vascular droplets. In the case of non-functionalized droplets with the objective of vessel occlusion, the <span class="hlt">bubbles</span> are transported by flow through vessel bifurcations, where they may split prior to eventually reach vessels small enough that they become lodged. This splitting behavior affects the distribution of <span class="hlt">bubbles</span> and the efficacy of flow occlusion and the treatment. In these studies, we investigated <span class="hlt">bubble</span> transport in bifurcations using computational and theoretical modeling. The model reproduces the variety of experimentally observed splitting behaviors. Splitting homogeneity and maximum shear stress along the vessel walls is predicted over a variety of physical parameters. Maximum shear stresses were found to decrease with increasing Reynolds number. The initial <span class="hlt">bubble</span> length was found to affect the splitting behavior in the presence of gravitational asymmetry. This work was supported by NIH Grant R01EB006476.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003JFM...476..345C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JFM...476..345C"><span>Compressible <span class="hlt">bubbles</span> in Stokes flow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crowdy, Darren G.</p> <p>2003-02-01</p> <p>The problem of a two-dimensional inviscid compressible <span class="hlt">bubble</span> evolving in Stokes flow is considered. By generalizing the work of Tanveer & Vasconcelos (1995) it is shown that for certain classes of initial condition the quasi-steady free boundary problem for the <span class="hlt">bubble</span> shape evolution is reducible to a finite set of coupled nonlinear ordinary differential equations, the form of which depends on the equation of state governing the relationship between the <span class="hlt">bubble</span> pressure and its area. Recent numerical calculations by Pozrikidis (2001) using boundary integral methods are retrieved and extended. If the ambient pressures are small enough, it is shown that <span class="hlt">bubbles</span> can expand significantly. It is also shown that a <span class="hlt">bubble</span> evolving adiabatically is less likely to expand than an isothermal <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SMat...13.8684F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SMat...13.8684F"><span><span class="hlt">Bubble</span> propagation on a rail: a concept for sorting <span class="hlt">bubbles</span> by size</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Franco-Gómez, Andrés; Thompson, Alice B.; Hazel, Andrew L.; Juel, Anne</p> <p></p> <p>We demonstrate experimentally that the introduction of a rail, a small height constriction, within the cross-section of a rectangular channel could be used as a robust passive sorting device in two-phase fluid flows. Single air <span class="hlt">bubbles</span> carried within silicone oil are generally transported on one side of the rail. However, for flow rates marginally larger than a critical value, a narrow band of <span class="hlt">bubble</span> sizes can propagate (stably) over the rail, while <span class="hlt">bubbles</span> of other sizes segregate to the side of the rail. The width of this band of <span class="hlt">bubble</span> sizes increases with flow rate and the size of the most stable <span class="hlt">bubble</span> can be tuned by varying the rail width. We present a complementary theoretical analysis based on a depth-averaged theory, which is in qualitative agreement with the experiments. The theoretical study reveals that the mechanism relies on a non-trivial interaction between capillary and viscous forces that is fully dynamic, rather than being a simple modification of capillary static solutions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26067442','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26067442"><span>Study of a Novel Method for the Thermolysis of Solutes in Aqueous Solution Using a Low Temperature <span class="hlt">Bubble</span> Column Evaporator.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shahid, Muhammad; Xue, Xinkai; Fan, Chao; Ninham, Barry W; Pashley, Richard M</p> <p>2015-06-25</p> <p>An enhanced thermal decomposition of chemical compounds in aqueous solution has been achieved at reduced solution temperatures. The technique exploits hitherto unrecognized properties of a <span class="hlt">bubble</span> column evaporator (BCE). It offers better heat transfer efficiency than conventional heat transfer equipment. This is obtained via a continuous flow of hot, dry air <span class="hlt">bubbles</span> of optimal (1-3 mm) size. Optimal <span class="hlt">bubble</span> size is maintained by using the <span class="hlt">bubble</span> coalescence inhibition property of some salts. This novel method is illustrated by a study of thermal decomposition of ammonium bicarbonate (NH4HCO3) and potassium persulfate (K2S2O8) in aqueous solutions. The decomposition occurs at significantly lower temperatures than those needed in bulk solution. The process appears to work via the continuous production of hot (e.g., 150 °C) dry air <span class="hlt">bubbles</span>, which do not heat the solution significantly but produce a transient hot surface layer around each <span class="hlt">rising</span> <span class="hlt">bubble</span>. This causes the thermal decomposition of the solute. The decomposition occurs due to the effective collision of the solute with the surface of the hot <span class="hlt">bubbles</span>. The new process could, for example, be applied to the regeneration of the ammonium bicarbonate draw solution used in forward osmosis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.G6001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.G6001B"><span>Acoustically-Enhanced Direct Contact Vapor <span class="hlt">Bubble</span> Condensation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boziuk, Thomas; Smith, Marc; Glezer, Ari</p> <p>2017-11-01</p> <p>Rate-limited, direct contact vapor condensation of vapor <span class="hlt">bubbles</span> that are formed by direct steam injection through a nozzle in a quiescent subcooled liquid bath is accelerated using ultrasonic (MHz-range) actuation. A submerged, low power actuator produces an acoustic beam whose radiation pressure deforms the liquid-vapor interface, leading to the formation of a liquid spear that penetrates the vapor <span class="hlt">bubble</span> to form a vapor torus with a significantly larger surface area and condensation rate. Ultrasonic focusing along the spear leads to the ejection of small, subcooled droplets through the vapor volume that impact the vapor-liquid interface and further enhance the condensation. High-speed Schlieren imaging of the formation and collapse of the vapor <span class="hlt">bubbles</span> in the absence and presence of actuation shows that the impulse associated with the collapse of the toroidal volume leads to the formation of a turbulent vortex ring in the liquid phase. Liquid motions near the condensing vapor volume are investigated in the absence and presence of acoustic actuation using high-magnification PIV and show the evolution of a liquid jet through the center of the condensing toroidal volume and the formation and advection of vortex ring structures whose impulse appear to increase with temperature difference between the liquid and vapor phases. High-speed image processing is used to assess the effect of the actuation on the temporal and spatial variations in the <span class="hlt">characteristic</span> scales and condensation rates of the vapor <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22340173-milky-way-project-leveraging-citizen-science-machine-learning-detect-interstellar-bubbles','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22340173-milky-way-project-leveraging-citizen-science-machine-learning-detect-interstellar-bubbles"><span>THE MILKY WAY PROJECT: LEVERAGING CITIZEN SCIENCE AND MACHINE LEARNING TO DETECT INTERSTELLAR <span class="hlt">BUBBLES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Beaumont, Christopher N.; Williams, Jonathan P.; Goodman, Alyssa A.</p> <p></p> <p>We present Brut, an algorithm to identify <span class="hlt">bubbles</span> in infrared images of the Galactic midplane. Brut is based on the Random Forest algorithm, and uses <span class="hlt">bubbles</span> identified by >35,000 citizen scientists from the Milky Way Project to discover the identifying <span class="hlt">characteristics</span> of <span class="hlt">bubbles</span> in images from the Spitzer Space Telescope. We demonstrate that Brut's ability to identify <span class="hlt">bubbles</span> is comparable to expert astronomers. We use Brut to re-assess the <span class="hlt">bubbles</span> in the Milky Way Project catalog, and find that 10%-30% of the objects in this catalog are non-<span class="hlt">bubble</span> interlopers. Relative to these interlopers, high-reliability <span class="hlt">bubbles</span> are more confined to themore » mid-plane, and display a stronger excess of young stellar objects along and within <span class="hlt">bubble</span> rims. Furthermore, Brut is able to discover <span class="hlt">bubbles</span> missed by previous searches—particularly <span class="hlt">bubbles</span> near bright sources which have low contrast relative to their surroundings. Brut demonstrates the synergies that exist between citizen scientists, professional scientists, and machine learning techniques. In cases where ''untrained' citizens can identify patterns that machines cannot detect without training, machine learning algorithms like Brut can use the output of citizen science projects as input training sets, offering tremendous opportunities to speed the pace of scientific discovery. A hybrid model of machine learning combined with crowdsourced training data from citizen scientists can not only classify large quantities of data, but also address the weakness of each approach if deployed alone.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6356E..12K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6356E..12K"><span><span class="hlt">Bubble</span> structure evaluation method of sponge cake by using image morphology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kato, Kunihito; Yamamoto, Kazuhiko; Nonaka, Masahiko; Katsuta, Yukiyo; Kasamatsu, Chinatsu</p> <p>2007-01-01</p> <p>Nowadays, many evaluation methods for food industry by using image processing are proposed. These methods are becoming new evaluation method besides the sensory test and the solid-state measurement that have been used for the quality evaluation recently. The goal of our research is structure evaluation of sponge cake by using the image processing. In this paper, we propose a feature extraction method of the bobble structure in the sponge cake. Analysis of the <span class="hlt">bubble</span> structure is one of the important properties to understand <span class="hlt">characteristics</span> of the cake from the image. In order to take the cake image, first we cut cakes and measured that's surface by using the CIS scanner, because the depth of field of this type scanner is very shallow. Therefore the <span class="hlt">bubble</span> region of the surface has low gray scale value, and it has a feature that is blur. We extracted <span class="hlt">bubble</span> regions from the surface images based on these features. The input image is binarized, and the feature of <span class="hlt">bubble</span> is extracted by the morphology analysis. In order to evaluate the result of feature extraction, we compared correlation with "Size of the <span class="hlt">bubble</span>" of the sensory test result. From a result, the <span class="hlt">bubble</span> extraction by using morphology analysis gives good correlation. It is shown that our method is as well as the subjectivity evaluation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPD....40.1007B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPD....40.1007B"><span>Prominence <span class="hlt">Bubbles</span> and Plumes: Thermo-magnetic Buoyancy in Coronal Cavity Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berger, Thomas; Hurlburt, N.</p> <p>2009-05-01</p> <p>The Hinode/Solar Optical Telescope continues to produce high spatial and temporal resolution images of solar prominences in both the Ca II 396.8 nm H-line and the H-alpha 656.3 nm line. Time series of these images show that many quiescent prominences produce large scale (50 Mm) dark "<span class="hlt">bubbles</span>" that "inflate" into, and sometimes burst through, the prominence material. In addition, small-scale (2--5 Mm) dark plumes are seen <span class="hlt">rising</span> into many quiescent prominences. We show typical examples of both phenomena and argue that they originate from the same mechanism: concentrated and heated magnetic flux that <span class="hlt">rises</span> due to thermal and magnetic buoyancy to equilibrium heights in the prominence/coronal-cavity system. More generally, these <span class="hlt">bubbles</span> and upflows offer a source of both magnetic flux and mass to the overlying coronal cavity, supporting B.C. Low's theory of CME initiation via steadily increasing magnetic buoyancy breaking through the overlying helmut streamer tension forces. Quiescent prominences are thus seen as the lowermost parts of the larger coronal cavity system, revealing through thermal effects both the cooled downflowing "drainage" from the cavity and the heated upflowing magnetic "plasmoids" supplying the cavity. We compare SOT movies to new 3D compressible MHD simulations that reproduce the dark turbulent plume dynamics to establish the magnetic and thermal character of these buoyancy-driven flows into the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDD21007M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDD21007M"><span>Gas depletion through single gas <span class="hlt">bubble</span> diffusive growth and its effect on subsequent <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moreno Soto, Alvaro; Prosperetti, Andrea; Lohse, Detlef; van der Meer, Devaraj; Physics of Fluid Group Collaboration; MCEC Netherlands CenterMultiscale Catalytic Energy Conversion Collaboration</p> <p>2016-11-01</p> <p>In weakly supersaturated mixtures, <span class="hlt">bubbles</span> are known to grow quasi-statically as diffusion-driven mass transfer governs the process. In the final stage of the evolution, before detachment, there is an enhancement of mass transfer, which changes from diffusion to natural convection. Once the <span class="hlt">bubble</span> detaches, it leaves behind a gas-depleted area. The diffusive mass transfer towards that region cannot compensate for the amount of gas which is taken away by the <span class="hlt">bubble</span>. Consequently, the consecutive <span class="hlt">bubble</span> will grow in an environment which contains less gas than for the previous one. This reduces the local supersaturation of the mixture around the nucleation site, leading to a reduced <span class="hlt">bubble</span> growth rate. We present quantitative experimental data on this effect and the theoretical model for depletion during the <span class="hlt">bubble</span> growth rate. This work was supported by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23534695','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23534695"><span>Electrohydrodynamic <span class="hlt">bubbling</span>: an alternative route to fabricate porous structures of silk fibroin based materials.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ekemen, Zeynep; Ahmad, Zeeshan; Stride, Eleanor; Kaplan, David; Edirisinghe, Mohan</p> <p>2013-05-13</p> <p>Conventional fabrication techniques and structures employed in the design of silk fibroin (SF) based porous materials provide only limited control over pore size and require several processing stages. In this study, it is shown that, by utilizing electrohydrodynamic <span class="hlt">bubbling</span>, not only can new hollow spherical structures of SF be formed in a single step by means of <span class="hlt">bubbles</span>, but the resulting <span class="hlt">bubbles</span> can serve as pore generators when dehydrated. The <span class="hlt">bubble</span> <span class="hlt">characteristics</span> can be controlled through simple adjustments to the processing parameters. <span class="hlt">Bubbles</span> with diameters in the range of 240-1000 μm were fabricated in controlled fashion. FT-IR characterization confirmed that the rate of air infused during processing enhanced β-sheet packing in SF at higher flow rates. Dynamic mechanical analysis also demonstrated a correlation between air flow rate and film tensile strength. Results indicate that electrohydrodynamically generated SF and their composite <span class="hlt">bubbles</span> can be employed as new tools to generate porous structures in a controlled manner with a range of potential applications in biocoatings and tissue engineering scaffolds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MS%26E..158a2003A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MS%26E..158a2003A"><span>The calculation of weakly non-spherical cavitation <span class="hlt">bubble</span> impact on a solid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aganin, A. A.; Guseva, T. S.; Kosolapova, L. A.; Khismatullina, N. A.</p> <p>2016-11-01</p> <p>The effect of small spheroidal non-sphericity of a cavitation <span class="hlt">bubble</span> touching a solid at the beginning of its collapse on its impact on the solid of a copper-nickel alloy is investigated. The impact on the solid is realized by means of a high-speed liquid jet arising at collapse on the <span class="hlt">bubble</span> surface. The shape of the jet, its velocity and pressure are calculated by the boundary element method. The spatial and temporal <span class="hlt">characteristics</span> of the pressure pulses on the solid surface are determined by the CIP-CUP method on dynamically adaptive grids without explicitly separating the gas-liquid interface. The solid surface layer dynamics is evaluated by the Godunov method. The results are analyzed in dimensionless variables obtained with using the water hammer pressure, the time moment and the jet-solid contact area radius at which the jet begins to spread on the solid surface. It is shown that in those dimensionless variables, the dependence of the spatial and temporal <span class="hlt">characteristics</span> of the solid surface pressure pulses on the initial <span class="hlt">bubble</span> shape non-sphericity is relatively small. The nonsphericity also slightly influences the main qualitative features of the dynamic processes inside the solid, whereas its effect on their quantitative <span class="hlt">characteristics</span> can be significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17358260','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17358260"><span>Single-<span class="hlt">bubble</span> sonoluminescence in sulfuric acid and water: <span class="hlt">bubble</span> dynamics, stability, and continuous spectra.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Puente, Gabriela F; García-Martínez, Pablo; Bonetto, Fabián J</p> <p>2007-01-01</p> <p>We present theoretical calculations of an argon <span class="hlt">bubble</span> in a liquid solution of 85%wt sulfuric acid and 15%wt water in single-<span class="hlt">bubble</span> sonoluminescence. We used a model without free parameters to be adjusted. We predict from first principles the region in parameter space for stable <span class="hlt">bubble</span> evolution, the temporal evolution of the <span class="hlt">bubble</span> radius, the maximum temperature, pressures, and the light spectra due to thermal emissions. We also used a partial differential equation based model (hydrocode) to compute the temperature and pressure evolutions at the center of the <span class="hlt">bubble</span> during maximum compression. We found the behavior of this liquid mixture to be very different from water in several aspects. Most of the models in sonoluminescence were compared with water experimental results.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920045467&hterms=divided+attention&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddivided%2Battention','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920045467&hterms=divided+attention&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddivided%2Battention"><span>Electric field observations of equatorial <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aggson, T. L.; Maynard, N. C.; Hanson, W. B.; Saba, Jack L.</p> <p>1992-01-01</p> <p>Results from the double floating probe experiment performed on the San Marco D satellite are presented, with emphasis on the observation of large incremental changes in the convective electric field vector at the boundary of equatorial plasma <span class="hlt">bubbles</span>. Attention is given to isolated <span class="hlt">bubble</span> structures in the upper ionospheric F regions; these observed <span class="hlt">bubble</span> encounters are divided into two types - type I (live <span class="hlt">bubbles</span>) and type II (dead <span class="hlt">bubbles</span>). Type I <span class="hlt">bubbles</span> show varying degrees of plasma depletion and large upward velocities range up to 1000 km/s. The geometry of these <span class="hlt">bubbles</span> is such that the spacecraft orbit may cut them where they are tilting either eastward or (more often) westward. Type II <span class="hlt">bubbles</span> exhibit plasma density depletion but no appreciable upward convection. Both types of events are usually surrounded by a halo of plasma turbulence, which can extend considerably beyond the region of plasma depletion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22399295-low-threshold-lasing-bubble-containing-glass-microspheres-non-whispering-gallery-mode-excitation-over-wide-wavelength-range','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22399295-low-threshold-lasing-bubble-containing-glass-microspheres-non-whispering-gallery-mode-excitation-over-wide-wavelength-range"><span>Low threshold lasing of <span class="hlt">bubble</span>-containing glass microspheres by non-whispering gallery mode excitation over a wide wavelength range</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kumagai, Tsutaru, E-mail: kumagai.t.af@m.titech.ac.jp; Kishi, Tetsuo; Yano, Tetsuji</p> <p>2015-03-21</p> <p><span class="hlt">Bubble</span>-containing Nd{sup 3+}-doped tellurite glass microspheres were fabricated by localized laser heating technique to investigate their optical properties for use as microresonators. Fluorescence and excitation spectra measurements were performed by pumping with a tunable CW-Ti:Sapphire laser. The excitation spectra manifested several sharp peaks due to the conventional whispering gallery mode (WGM) when the pumping laser was irradiated to the edge part of the microsphere. However, when the excitation light was irradiated on the <span class="hlt">bubble</span> position inside the microsphere, “non-WGM excitation” was induced, giving <span class="hlt">rise</span> to numerous peaks at a broad wavelength range in the excitation spectra. Thus, efficient excitation wasmore » achieved over a wide wavelength range. Lasing threshold excited at the <span class="hlt">bubble</span> position was much lower than that for the excitation at the edges of the microsphere. The lowest value of the laser threshold was 34 μW for a 4 μm sphere containing a 0.5 μm <span class="hlt">bubble</span>. Efficiency of the excitation at the <span class="hlt">bubble</span> position with broadband light was calculated to be 5 times higher than that for the edge of the microsphere. The <span class="hlt">bubble</span>-containing microsphere enables efficient utilization of broadband light excitation from light-emitting diodes and solar light.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDG21001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDG21001B"><span>Interfacial Dynamics of Condensing Vapor <span class="hlt">Bubbles</span> in an Ultrasonic Acoustic Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boziuk, Thomas; Smith, Marc; Glezer, Ari</p> <p>2016-11-01</p> <p>Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor <span class="hlt">bubbles</span> are formed by direct injection from a pressurized steam reservoir through nozzles of varying <span class="hlt">characteristic</span> diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor <span class="hlt">bubble</span> and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in <span class="hlt">characteristic</span> scale (and condensation rate) of the vapor <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870011043','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870011043"><span><span class="hlt">Bubble</span> memory module for spacecraft application</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hayes, P. J.; Looney, K. T.; Nichols, C. D.</p> <p>1985-01-01</p> <p><span class="hlt">Bubble</span> domain technology offers an all-solid-state alternative for data storage in onboard data systems. A versatile modular <span class="hlt">bubble</span> memory concept was developed. The key module is the <span class="hlt">bubble</span> memory module which contains all of the storage devices and circuitry for accessing these devices. This report documents the <span class="hlt">bubble</span> memory module design and preliminary hardware designs aimed at memory module functional demonstration with available commercial <span class="hlt">bubble</span> devices. The system architecture provides simultaneous operation of <span class="hlt">bubble</span> devices to attain high data rates. Banks of <span class="hlt">bubble</span> devices are accessed by a given <span class="hlt">bubble</span> controller to minimize controller parts. A power strobing technique is discussed which could minimize the average system power dissipation. A fast initialization method using EEPROM (electrically erasable, programmable read-only memory) devices promotes fast access. Noise and crosstalk problems and implementations to minimize these are discussed. Flight memory systems which incorporate the concepts and techniques of this work could now be developed for applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvD..95j3513H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvD..95j3513H"><span>Consistent cosmic <span class="hlt">bubble</span> embeddings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haque, S. Shajidul; Underwood, Bret</p> <p>2017-05-01</p> <p>The Raychaudhuri equation for null rays is a powerful tool for finding consistent embeddings of cosmological <span class="hlt">bubbles</span> in a background spacetime in a way that is largely independent of the matter content. We find that spatially flat or positively curved thin wall <span class="hlt">bubbles</span> surrounded by a cosmological background must have a Hubble expansion that is either contracting or expanding slower than the background, which is a more stringent constraint than those obtained by the usual Israel thin-wall formalism. Similarly, a cosmological <span class="hlt">bubble</span> surrounded by Schwarzschild space, occasionally used as a simple "swiss cheese" model of inhomogenities in an expanding universe, must be contracting (for spatially flat and positively curved <span class="hlt">bubbles</span>) and bounded in size by the apparent horizon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11973104','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11973104"><span>Endothelial protection: avoiding air <span class="hlt">bubble</span> formation at the phacoemulsification tip.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Eung Kweon; Cristol, Stephen M; Kang, Shin J; Edelhauser, Henry F; Yeon, Dong-Soo; Lee, Jae Bum</p> <p>2002-03-01</p> <p>To investigate the conditions under which <span class="hlt">bubbles</span> form during phacoemulsification. Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea. In the first part of the study, the partial pressure of oxygen (pO(2)) was used as a surrogate measure for the partial pressure of air. Irrigation solutions packaged in glass and plastic containers were studied. A directly vented glass bottle was also tested. The pO(2) of the various irrigation solutions was measured as the containers were emptied. In the second part, phacoemulsification procedures were performed in rabbit eyes with different power settings and different irrigation solutions. Intracameral <span class="hlt">bubble</span> formation during the procedure was recorded. Following the phacoemulsification procedures, the corneas were stained for F-actin and examined for endothelial injury. The initial pO(2) in irrigation solutions packaged in glass bottles was about half that at atmospheric levels; in solutions packaged in plastic, it was at atmospheric levels. As irrigation solutions were drained from the container, the pO(2) of the solution tended to <span class="hlt">rise</span> toward atmospheric levels. The rate of pO(2) increase was markedly reduced by using a directly vented glass bottle. In the phacoemulsification procedures, <span class="hlt">bubble</span> formation was most likely to occur with higher pO(2) and higher power settings. Observation of <span class="hlt">bubbles</span> by the surgeon was highly correlated with endothelial damage. Keeping the pO(2) low reduced the risk of endothelial damage, especially at higher phacoemulsification powers. The packaging of irrigation solutions was the most important factor in controlling the initial pO(2) of the solution. The pO(2) can be minimized throughout a phacoemulsification procedure by using a directly vented glass bottle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AmJPh..86..250L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AmJPh..86..250L"><span>Sinking <span class="hlt">bubbles</span> in stout beers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, W. T.; Kaar, S.; O'Brien, S. B. G.</p> <p>2018-04-01</p> <p>A surprising phenomenon witnessed by many is the sinking <span class="hlt">bubbles</span> seen in a settling pint of stout beer. <span class="hlt">Bubbles</span> are less dense than the surrounding fluid so how does this happen? Previous work has shown that the explanation lies in a circulation of fluid promoted by the tilted sides of the glass. However, this work has relied heavily on computational fluid dynamics (CFD) simulations. Here, we show that the phenomenon of sinking <span class="hlt">bubbles</span> can be predicted using a simple analytic model. To make the model analytically tractable, we work in the limit of small <span class="hlt">bubbles</span> and consider a simplified geometry. The model confirms both the existence of sinking <span class="hlt">bubbles</span> and the previously proposed mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21993505','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21993505"><span><span class="hlt">Bubbles</span> in live-stranded dolphins.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dennison, S; Moore, M J; Fahlman, A; Moore, K; Sharp, S; Harry, C T; Hoppe, J; Niemeyer, M; Lentell, B; Wells, R S</p> <p>2012-04-07</p> <p><span class="hlt">Bubbles</span> in supersaturated tissues and blood occur in beaked whales stranded near sonar exercises, and post-mortem in dolphins bycaught at depth and then hauled to the surface. To evaluate live dolphins for <span class="hlt">bubbles</span>, liver, kidneys, eyes and blubber-muscle interface of live-stranded and capture-release dolphins were scanned with B-mode ultrasound. Gas was identified in kidneys of 21 of 22 live-stranded dolphins and in the hepatic portal vasculature of 2 of 22. Nine then died or were euthanized and <span class="hlt">bubble</span> presence corroborated by computer tomography and necropsy, 13 were released of which all but two did not re-strand. <span class="hlt">Bubbles</span> were not detected in 20 live wild dolphins examined during health assessments in shallow water. Off-gassing of supersaturated blood and tissues was the most probable origin for the gas <span class="hlt">bubbles</span>. In contrast to marine mammals repeatedly diving in the wild, stranded animals are unable to recompress by diving, and thus may retain <span class="hlt">bubbles</span>. Since the majority of beached dolphins released did not re-strand it also suggests that minor <span class="hlt">bubble</span> formation is tolerated and will not lead to clinically significant decompression sickness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17234444','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17234444"><span><span class="hlt">Bubbles</span> in an acoustic field: an overview.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ashokkumar, Muthupandian; Lee, Judy; Kentish, Sandra; Grieser, Franz</p> <p>2007-04-01</p> <p>Acoustic cavitation is the fundamental process responsible for the initiation of most of the sonochemical reactions in liquids. Acoustic cavitation originates from the interaction between sound waves and <span class="hlt">bubbles</span>. In an acoustic field, <span class="hlt">bubbles</span> can undergo growth by rectified diffusion, <span class="hlt">bubble-bubble</span> coalescence, <span class="hlt">bubble</span> dissolution or <span class="hlt">bubble</span> collapse leading to the generation of primary radicals and other secondary chemical reactions. Surface active solutes have been used in association with a number of experimental techniques in order to isolate and understand these activities. A strobe technique has been used for monitoring the growth of a single <span class="hlt">bubble</span> by rectified diffusion. Multibubble sonoluminescence has been used for monitoring the growth of the <span class="hlt">bubbles</span> as well as coalescence between <span class="hlt">bubbles</span>. The extent of <span class="hlt">bubble</span> coalescence has also been monitored using a newly developed capillary technique. An overview of the various experimental results has been presented in order to highlight the complexities involved in acoustic cavitation processes, which on the other hand arise from a simple, mechanical interaction between sound waves and <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4454370','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4454370"><span>A New Active Cavitation Mapping Technique for Pulsed HIFU Applications – <span class="hlt">Bubble</span> Doppler</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Tong; Khokhlova, Tatiana; Sapozhnikov, Oleg; Hwang, Joo Ha; Sapozhnikov, Oleg; O’Donnell, Matthew</p> <p>2015-01-01</p> <p>In this work, a new active cavitation mapping technique for pulsed high-intensity focused ultrasound (pHIFU) applications termed <span class="hlt">bubble</span> Doppler is proposed and its feasibility tested in tissue-mimicking gel phantoms. pHIFU therapy uses short pulses, delivered at low pulse repetition frequency, to cause transient <span class="hlt">bubble</span> activity that has been shown to enhance drug and gene delivery to tissues. The current gold standard for detecting and monitoring cavitation activity during pHIFU treatments is passive cavitation detection (PCD), which provides minimal information on the spatial distribution of the <span class="hlt">bubbles</span>. B-mode imaging can detect hyperecho formation, but has very limited sensitivity, especially to small, transient microbubbles. The <span class="hlt">bubble</span> Doppler method proposed here is based on a fusion of the adaptations of three Doppler techniques that had been previously developed for imaging of ultrasound contrast agents – color Doppler, pulse inversion Doppler, and decorrelation Doppler. Doppler ensemble pulses were interleaved with therapeutic pHIFU pulses using three different pulse sequences and standard Doppler processing was applied to the received echoes. The information yielded by each of the techniques on the distribution and <span class="hlt">characteristics</span> of pHIFU-induced cavitation <span class="hlt">bubbles</span> was evaluated separately, and found to be complementary. The unified approach - <span class="hlt">bubble</span> Doppler – was then proposed to both spatially map the presence of transient <span class="hlt">bubbles</span> and to estimate their sizes and the degree of nonlinearity. PMID:25265178</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvX...6a1010T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvX...6a1010T"><span>Probing the Mechanical Strength of an Armored <span class="hlt">Bubble</span> and Its Implication to Particle-Stabilized Foams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taccoen, Nicolas; Lequeux, François; Gunes, Deniz Z.; Baroud, Charles N.</p> <p>2016-01-01</p> <p><span class="hlt">Bubbles</span> are dynamic objects that grow and <span class="hlt">rise</span> or shrink and disappear, often on the scale of seconds. This conflicts with their uses in foams where they serve to modify the properties of the material in which they are embedded. Coating the <span class="hlt">bubble</span> surface with solid particles has been demonstrated to strongly enhance the foam stability, although the mechanisms for such stabilization remain mysterious. In this paper, we reduce the problem of foam stability to the study of the behavior of a single spherical <span class="hlt">bubble</span> coated with a monolayer of solid particles. The behavior of this armored <span class="hlt">bubble</span> is monitored while the ambient pressure around it is varied, in order to simulate the dissolution stress resulting from the surrounding foam. We find that above a critical stress, localized dislocations appear on the armor and lead to a global loss of the mechanical stability. Once these dislocations appear, the armor is unable to prevent the dissolution of the gas into the surrounding liquid, which translates into a continued reduction of the <span class="hlt">bubble</span> volume, even for a fixed overpressure. The observed route to the armor failure therefore begins from localized dislocations that lead to large-scale deformations of the shell until the <span class="hlt">bubble</span> completely dissolves. The critical value of the ambient pressure that leads to the failure depends on the <span class="hlt">bubble</span> radius, with a scaling of Δ Pcollapse∝R-1 , but does not depend on the particle diameter. These results disagree with the generally used elastic models to describe particle-covered interfaces. Instead, the experimental measurements are accounted for by an original theoretical description that equilibrates the energy gained from the gas dissolution with the capillary energy cost of displacing the individual particles. The model recovers the short-wavelength instability, the scaling of the collapse pressure with <span class="hlt">bubble</span> radius, and the insensitivity to particle diameter. Finally, we use this new microscopic understanding to predict</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhFl...29c7103Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhFl...29c7103Q"><span>Stream-wise distribution of skin-friction drag reduction on a flat plate with <span class="hlt">bubble</span> injection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Shijie; Chu, Ning; Yao, Yan; Liu, Jingting; Huang, Bin; Wu, Dazhuan</p> <p>2017-03-01</p> <p>To investigate the stream-wise distribution of skin-friction drag reduction on a flat plate with <span class="hlt">bubble</span> injection, both experiments and simulations of <span class="hlt">bubble</span> drag reduction (BDR) have been conducted in this paper. Drag reductions at various flow speeds and air injection rates have been tested in cavitation tunnel experiments. Visualization of <span class="hlt">bubble</span> flow pattern is implemented synchronously. The computational fluid dynamics (CFD) method, in the framework of Eulerian-Eulerian two fluid modeling, coupled with population balance model (PBM) is used to simulate the <span class="hlt">bubbly</span> flow along the flat plate. A wide range of <span class="hlt">bubble</span> sizes considering <span class="hlt">bubble</span> breakup and coalescence is modeled based on experimental <span class="hlt">bubble</span> distribution images. Drag and lift forces are fully modeled based on applicable closure models. Both predicted drag reductions and <span class="hlt">bubble</span> distributions are in reasonable concordance with experimental results. Stream-wise distribution of BDR is revealed based on CFD-PBM numerical results. In particular, four distinct regions with different BDR <span class="hlt">characteristics</span> are first identified and discussed in this study. Thresholds between regions are extracted and discussed. And it is highly necessary to fully understand the stream-wise distribution of BDR in order to establish a universal scaling law. Moreover, mechanism of stream-wise distribution of BDR is analysed based on the near-wall flow parameters. The local drag reduction is a direct result of near-wall max void fraction. And the near-wall velocity gradient modified by the presence of <span class="hlt">bubbles</span> is considered as another important factor for <span class="hlt">bubble</span> drag reduction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.449...26V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.449...26V"><span>Models for viscosity and shear localization in <span class="hlt">bubble</span>-rich magmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vona, Alessandro; Ryan, Amy G.; Russell, James K.; Romano, Claudia</p> <p>2016-09-01</p> <p><span class="hlt">Bubble</span> content influences magma rheology and, thus, styles of volcanic eruption. Increasing magma vesicularity affects the bulk viscosity of the <span class="hlt">bubble</span>-melt suspension and has the potential to promote non-Newtonian behavior in the form of shear localization or brittle failure. Here, we present a series of high temperature uniaxial deformation experiments designed to investigate the effect of <span class="hlt">bubbles</span> on the magma bulk viscosity. The starting materials are cores of natural rhyolitic obsidian synthesized to have variable vesicularity (ϕ = 0- 66%). The foamed cores were deformed isothermally (T = 750 °C) at atmospheric conditions using a high-temperature uniaxial press under constant displacement rates (strain rates between 0.5- 1 ×10-4 s-1) and to total strains of 10-40%. The viscosity of the <span class="hlt">bubble</span>-free melt (η0) was measured by micropenetration and parallel plate methods to establish a baseline for experiments on the vesicle rich cores. At the experimental conditions, <span class="hlt">rising</span> vesicle content produces a marked decrease in bulk viscosity that is best described by a two-parameter empirical equation: log10 ηBulk =log10 η0 - 1.47[ ϕ / (1 - ϕ) ] 0.48. Our parameterization of the <span class="hlt">bubble</span>-melt rheology is combined with Maxwell relaxation theory to map the potential onset of non-Newtonian behavior (shear localization) in magmas as a function of melt viscosity, vesicularity, and strain rate. For low degrees of strain (i.e. as in our study), the rheological properties of vesicular magmas under different flow types (pure vs. simple shear) are indistinguishable. For high strain or strain rates where simple and pure shear viscosity values may diverge, our model represents a maximum boundary condition. Vesicular magmas can behave as non-Newtonian fluids at lower strain rates than unvesiculated melts, thereby, promoting shear localization and (explosive or non-explosive) magma fragmentation. The extent of shear localization in magma influences outgassing efficiency</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26187759','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26187759"><span>Mechanisms of single <span class="hlt">bubble</span> cleaning.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reuter, Fabian; Mettin, Robert</p> <p>2016-03-01</p> <p>The dynamics of collapsing <span class="hlt">bubbles</span> close to a flat solid is investigated with respect to its potential for removal of surface attached particles. Individual <span class="hlt">bubbles</span> are created by nanosecond Nd:YAG laser pulses focused into water close to glass plates contaminated with melamine resin micro-particles. The <span class="hlt">bubble</span> dynamics is analysed by means of synchronous high-speed recordings. Due to the close solid boundary, the <span class="hlt">bubble</span> collapses with the well-known liquid jet phenomenon. Subsequent microscopic inspection of the substrates reveals circular areas clean of particles after a single <span class="hlt">bubble</span> generation and collapse event. The detailed <span class="hlt">bubble</span> dynamics, as well as the cleaned area size, is characterised by the non-dimensional <span class="hlt">bubble</span> stand-off γ=d/Rmax, with d: laser focus distance to the solid boundary, and Rmax: maximum <span class="hlt">bubble</span> radius before collapse. We observe a maximum of clean area at γ≈0.7, a roughly linear decay of the cleaned circle radius for increasing γ, and no cleaning for γ>3.5. As the main mechanism for particle removal, rapid flows at the boundary are identified. Three different cleaning regimes are discussed in relation to γ: (I) For large stand-off, 1.8<γ<3.5, <span class="hlt">bubble</span> collapse induced vortex flows touch down onto the substrate and remove particles without significant contact of the gas phase. (II) For small distances, γ<1.1, the <span class="hlt">bubble</span> is in direct contact with the solid. Fast liquid flows at the substrate are driven by the jet impact with its subsequent radial spreading, and by the liquid following the motion of the collapsing and rebounding <span class="hlt">bubble</span> wall. Both flows remove particles. Their relative timing, which depends sensitively on the exact γ, appears to determine the extension of the area with forces large enough to cause particle detachment. (III) At intermediate stand-off, 1.1<γ<1.8, only the second <span class="hlt">bubble</span> collapse touches the substrate, but acts with cleaning mechanisms similar to an effective small γ collapse: particles are removed by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26172798','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26172798"><span>Dynamics of two-dimensional <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piedra, Saúl; Ramos, Eduardo; Herrera, J Ramón</p> <p>2015-06-01</p> <p>The dynamics of two-dimensional <span class="hlt">bubbles</span> ascending under the influence of buoyant forces is numerically studied with a one-fluid model coupled with the front-tracking technique. The <span class="hlt">bubble</span> dynamics are described by recording the position, shape, and orientation of the <span class="hlt">bubbles</span> as functions of time. The qualitative properties of the <span class="hlt">bubbles</span> and their terminal velocities are described in terms of the Eötvos (ratio of buoyancy to surface tension) and Archimedes numbers (ratio of buoyancy to viscous forces). The terminal Reynolds number result from the balance of buoyancy and drag forces and, consequently, is not an externally fixed parameter. In the cases that yield small Reynolds numbers, the <span class="hlt">bubbles</span> follow straight paths and the wake is steady. A more interesting behavior is found at high Reynolds numbers where the <span class="hlt">bubbles</span> follow an approximately periodic zigzag trajectory and an unstable wake with properties similar to the Von Karman vortex street is formed. The dynamical features of the motion of single <span class="hlt">bubbles</span> are compared to experimental observations of air <span class="hlt">bubbles</span> ascending in a water-filled Hele-Shaw cell. Although the comparison is not strictly valid in the sense that the effect of the lateral walls is not incorporated in the model, most of the dynamical properties observed are in good qualitative agreement with the numerical calculations. Hele-Shaw cells with different gaps have been used to determine the degree of approximation of the numerical calculation. It is found that for the relation between the terminal Reynolds number and the Archimedes number, the numerical calculations are closer to the observations of <span class="hlt">bubble</span> dynamics in Hele-Shaw cells of larger gaps.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002PhRvE..66d6630H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002PhRvE..66d6630H"><span>Acoustical stability of a sonoluminescing <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holzfuss, Joachim; Rüggeberg, Matthias; Holt, R. Glynn</p> <p>2002-10-01</p> <p>In the parameter region for sonoluminescence of a single levitated <span class="hlt">bubble</span> in a water-filled resonator it is observed that the <span class="hlt">bubble</span> may have an enormous spatial stability leaving it ``pinned'' in the fluid and allowing it to emit light pulses of picosecond accuracy. We report here observations of a complex harmonic structure in the acoustic field surrounding a sonoluminescing <span class="hlt">bubble</span>. We show that this complex sound field determines the position of the <span class="hlt">bubble</span> and may either increase or decrease its spatial stability. The acoustic environment of the <span class="hlt">bubble</span> is the result of the excitation of high-order normal modes of the resonator by the outgoing shock wave generated by the <span class="hlt">bubble</span> collapse.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..MARJ28002S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..MARJ28002S"><span>Between soap <span class="hlt">bubbles</span> and vesicles: The dynamics of freely floating smectic <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stannarius, Ralf; May, Kathrin; Harth, Kirsten; Trittel, Torsten</p> <p>2013-03-01</p> <p>The dynamics of droplets and <span class="hlt">bubbles</span>, particularly on microscopic scales, are of considerable importance in biological, environmental, and technical contexts. We introduce freely floating <span class="hlt">bubbles</span> of smectic liquid crystals and report their unique dynamic properties. Smectic <span class="hlt">bubbles</span> can be used as simple models for dynamic studies of fluid membranes. In equilibrium, they form minimal surfaces like soap films. However, shape transformations of closed smectic membranes that change the surface area involve the formation and motion of molecular layer dislocations. These processes are slow compared to the capillary wave dynamics, therefore the effective surface tension is zero like in vesicles. Freely floating smectic <span class="hlt">bubbles</span> are prepared from collapsing catenoid films and their dynamics is studied with optical high-speed imaging. Experiments are performed under normal gravity and in microgravity during parabolic flights. Supported by DLR within grant OASIS-Co.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Polyhedron&pg=2&id=EJ185654','ERIC'); return false;" href="https://eric.ed.gov/?q=Polyhedron&pg=2&id=EJ185654"><span>Cohesion of <span class="hlt">Bubbles</span> in Foam</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ross, Sydney</p> <p>1978-01-01</p> <p>The free-energy change, or binding energy, of an idealized <span class="hlt">bubble</span> cluster is calculated on the basis of one mole of gas, and on the basis of a single <span class="hlt">bubble</span> going from sphere to polyhedron. Some new relations of <span class="hlt">bubble</span> geometry are developed in the course of the calculation. (BB)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5220441','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/5220441"><span>Monitoring and analyzing waste glass compositions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Schumacher, R.F.</p> <p>1994-03-01</p> <p>A device and method are described for determining the viscosity of a fluid, preferably molten glass. The apparatus and method use the velocity of <span class="hlt">rising</span> <span class="hlt">bubbles</span>, preferably helium <span class="hlt">bubbles</span>, within the molten glass to determine the viscosity of the molten glass. The <span class="hlt">bubbles</span> are released from a tube positioned below the surface of the molten glass so that the <span class="hlt">bubbles</span> pass successively between two sets of electrodes, one above the other, that are continuously monitoring the conductivity of the molten glass. The measured conductivity will change as a <span class="hlt">bubble</span> passes between the electrodes enabling an accurate determination of when a <span class="hlt">bubble</span> has passed between the electrodes. The velocity of <span class="hlt">rising</span> <span class="hlt">bubbles</span> can be determined from the time interval between a change in conductivity of the first electrode pair and the second, upper electrode pair. The velocity of the <span class="hlt">rise</span> of the <span class="hlt">bubbles</span> in the glass melt is used in conjunction with other physical <span class="hlt">characteristics</span>, obtained by known methods, to determine the viscosity of the glass melt fluid and, hence, glass quality. 2 figures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/869169','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/869169"><span>Monitoring and analyzing waste glass compositions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Schumacher, Ray F.</p> <p>1994-01-01</p> <p>A device and method for determining the viscosity of a fluid, preferably molten glass. The apparatus and method uses the velocity of <span class="hlt">rising</span> <span class="hlt">bubbles</span>, preferably helium <span class="hlt">bubbles</span>, within the molten glass to determine the viscosity of the molten glass. The <span class="hlt">bubbles</span> are released from a tube positioned below the surface of the molten glass so that the <span class="hlt">bubbles</span> pass successively between two sets of electrodes, one above the other, that are continuously monitoring the conductivity of the molten glass. The measured conductivity will change as a <span class="hlt">bubble</span> passes between the electrodes enabling an accurate determination of when a <span class="hlt">bubble</span> has passed between the electrodes. The velocity of <span class="hlt">rising</span> <span class="hlt">bubbles</span> can be determined from the time interval between a change in conductivity of the first electrode pair and the second, upper electrode pair. The velocity of the <span class="hlt">rise</span> of the <span class="hlt">bubbles</span> in the glass melt is used in conjunction with other physical <span class="hlt">characteristics</span>, obtained by known methods, to determine the viscosity of the glass melt fluid and, hence, glass quality.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15181804','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15181804"><span>Shock-wave propagation and cavitation <span class="hlt">bubble</span> oscillation by Nd:YAG laser ablation of a metal in water.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Xiao; Xu, Rong-Qing; Chen, Jian-Ping; Shen, Zhong-Hua; Jian, Lu; Ni, Xiao-Wu</p> <p>2004-06-01</p> <p>A highly sensitive fiber-optic sensor based on optical beam deflection is applied for investigating the propagation of a laser-induced plasma shock wave, the oscillation of a cavitation <span class="hlt">bubble</span> diameter, and the development of a <span class="hlt">bubble</span>-collapse-induced shock wave when a Nd:YAG laser pulse is focused upon an aluminum surface in water. By the sequence of experimental waveforms detected at different distances, the attenuation properties of the plasma shock wave and of the <span class="hlt">bubble</span>-collapse-induced shock wave are obtained. Besides, based on <span class="hlt">characteristic</span> signals, both the maximum and the minimum <span class="hlt">bubble</span> radii at each oscillation cycle are determined, as are the corresponding oscillating periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=SOAP&pg=3&id=EJ1115198','ERIC'); return false;" href="https://eric.ed.gov/?q=SOAP&pg=3&id=EJ1115198"><span>The Early Years: Blowing <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ashbrook, Peggy</p> <p>2016-01-01</p> <p>Blowing <span class="hlt">bubbles</span> is not only a favorite summer activity for young children. Studying <span class="hlt">bubbles</span> that are grouped together, or "foam," is fun for children and fascinating to many real-world scientists. Foam is widely used--from the bedroom (mattresses) to outer space (insulating panels on spacecraft). <span class="hlt">Bubble</span> foam can provide children a…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5847080-infinite-stream-hele-shaw-bubbles','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5847080-infinite-stream-hele-shaw-bubbles"><span>Infinite stream of Hele--Shaw <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Burgess, D.; Tanveer, S.</p> <p>1991-03-01</p> <p>Exact solutions are presented for a steady stream of <span class="hlt">bubbles</span> in a Hele--Shaw cell when the effect of surface tension is neglected. These solutions form a three-parameter family. For specified area and distance between <span class="hlt">bubbles</span>, the speed of the <span class="hlt">bubble</span> remains arbitrary when surface tension is neglected. However, numerical and analytical evidence indicates that this arbitrariness is removed by the effect of surface tension. The branch of solutions that corresponds to the McLean--Saffman finger solution were primarily studied. A dramatic increase was observed in <span class="hlt">bubble</span> speeds when the distance between <span class="hlt">bubbles</span> is on the order of a <span class="hlt">bubble</span> diameter, whichmore » may have relevance to experiments done by Maxworthy (J. Fluid Mech. {bold 173}, 95 (1986)).« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000JChEd..77.1339C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000JChEd..77.1339C"><span>Time-Dependent Changes in a Shampoo <span class="hlt">Bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chattopadhyay, Arun</p> <p>2000-10-01</p> <p>This article demonstrates the fascinating phenomenon of time evolution of a shampoo <span class="hlt">bubble</span> through experiments that can be performed by undergraduate students. The changes in thickness of the <span class="hlt">bubble</span> films with time are followed by UV-vis spectroscopy. The change in chemical composition as a <span class="hlt">bubble</span> film evolves is monitored by FTIR spectroscopy. It is observed that the change in thickness of a typical shampoo <span class="hlt">bubble</span> film enclosed in a container is gradual and slow, and the hydrocarbon components of the <span class="hlt">bubble</span> drain from the <span class="hlt">bubble</span> much more slowly than water. An additional agent, such as acetonitrile, strikingly alters the dynamics of evolution of such a <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..MARH17006A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..MARH17006A"><span><span class="hlt">Bubbles</span> are responsive materials interesting for nonequilibrium physics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andreeva, Daria; Granick, Steve</p> <p></p> <p>Understanding of nature and conditions of non-equilibrium transformations of <span class="hlt">bubbles</span>, droplets, polysomes and vesicles in a gradient filed is a breath-taking question that dissipative systems raise. We ask: how to establish a dynamic control of useful <span class="hlt">characteristics</span>, for example dynamic control of morphology and composition modulation in soft matter. A possible answer is to develop a new generation of dynamic impactors that can trigger spatiotemporal oscillations of structures and functions. We aim to apply acoustic filed for development of temperature and pressure oscillations at a microscale area. We demonstrate amazing dynamic behavior of gas-filled <span class="hlt">bubbles</span> in pressure gradient field using a unique technique combining optical imaging, high intensity ultrasound and high speed camera. We find that pressure oscillations trigger continuous phase transformations that are considered to be impossible in physical systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDH14003R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDH14003R"><span><span class="hlt">Bubble</span> baths: just splashing around?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, Wesley; Speirs, Nathan; Sharker, Saberul Islam; Hurd, Randy; Williams, Bj; Truscott, Tadd</p> <p>2016-11-01</p> <p>Soap <span class="hlt">Bubbles</span> on the water surface would seem to be an intuitive means for splash suppression, but their presence appears to be a double edged sword. We present on the water entry of hydrophilic spheres where the liquid surface is augmented by the presence of a <span class="hlt">bubble</span> layer, similar to a <span class="hlt">bubble</span> bath. While the presence of a <span class="hlt">bubble</span> layer can diminish splashing upon impact at low Weber numbers, it also induces cavity formation at speeds below the critical velocity. The formation of a cavity generally results in larger Worthington jets and thus, larger amounts of ejected liquid. <span class="hlt">Bubble</span> layers induce cavity formation by wetting the sphere prior to liquid impact, causing them to form cavities similar to those created by hydrophobic spheres. Droplets present on a pre-wetted sphere disrupt the flow of the advancing liquid during entry, pushing it away from the impacting body to form an entrained air cavity. This phenomena was noted by Worthington with pre-wetted stone marbles, and suggests that the application of a <span class="hlt">bubble</span> layer is generally ineffective as a means of splash suppression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1282..115L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1282..115L"><span>OH Production Enhancement in <span class="hlt">Bubbling</span> Pulsed Discharges</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lungu, Cristian P.; Porosnicu, Corneliu; Jepu, Ionut; Chiru, Petrica; Zaroschi, Valentin; Lungu, Ana M.; Saito, Nagahiro; Bratescu, Maria; Takai, Osamu; Velea, Theodor; Predica, Vasile</p> <p>2010-10-01</p> <p>The generation of active species, such as H2O2, O*, OH*, HO2*, O3, N2*, etc, produced in aqueous solutions by HV pulsed discharges was studied in order to find the most efficient way in waste water treatment taking into account that these species are almost stronger oxidizers than ozone. Plasma was generated inside gas <span class="hlt">bubbles</span> formed by the argon, air and oxygen gas flow between the special designed electrodes. The pulse width and pulse frequency influence was studied in order to increase the efficiency of the OH active species formation. The produced active species were investigated by optical emission spectroscopy and correlated with electrical parameters of the discharges (frequency, pulse width, amplitude, and <span class="hlt">rise</span> and decay time).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17053668','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17053668"><span>Movement <span class="hlt">characteristics</span> of persons with prader-willi syndrome <span class="hlt">rising</span> from supine.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Belt, A B; Hertel, T A; Mante, J R; Marks, T; Rockett, V L; Wade, C; Clayton-Krasinski, D</p> <p>2001-01-01</p> <p>The purposes of this study were to: 1) determine if previously published descriptors of the supine to stand <span class="hlt">rising</span> task in healthy individuals could be applied to the movements of persons with Prader-Willi Syndrome (PWS); and 2) assess upper extremity (UE), axial region (AX), and lower extremity (LE) movements among subjects with PWS compared with controls. Nine subjects with PWS (seven-36 years of age) and matched controls were videotaped performing 10 <span class="hlt">rising</span> trials. The UE, AX, and LE movements were classified using published descriptors. Occurrence frequencies of movement patterns, duration of movement, and the relationships among body region movement score, BMI, and age were determined. Subjects with PWS utilized developmentally less advanced asymmetrical <span class="hlt">rising</span> patterns, took longer to <span class="hlt">rise</span>, and demonstrated less within subject variability than controls. Categorical descriptors, with minor modifications, can be used to describe <span class="hlt">rising</span> movements in persons with PWS. Knowledge of successful <span class="hlt">rising</span> patterns may assist PTs when examining or planning intervention strategies for teaching the <span class="hlt">rising</span> task.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24468106','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24468106"><span>Neural basis of economic <span class="hlt">bubble</span> behavior.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ogawa, A; Onozaki, T; Mizuno, T; Asamizuya, T; Ueno, K; Cheng, K; Iriki, A</p> <p>2014-04-18</p> <p>Throughout human history, economic <span class="hlt">bubbles</span> have formed and burst. As a <span class="hlt">bubble</span> grows, microeconomic behavior ceases to be constrained by realistic predictions. This contradicts the basic assumption of economics that agents have rational expectations. To examine the neural basis of behavior during <span class="hlt">bubbles</span>, we performed functional magnetic resonance imaging while participants traded shares in a virtual stock exchange with two non-<span class="hlt">bubble</span> stocks and one <span class="hlt">bubble</span> stock. The price was largely deflected from the fair price in one of the non-<span class="hlt">bubble</span> stocks, but not in the other. Their fair prices were specified. The price of the <span class="hlt">bubble</span> stock showed a large increase and battering, as based on a real stock-market bust. The imaging results revealed modulation of the brain circuits that regulate trade behavior under different market conditions. The premotor cortex was activated only under a market condition in which the price was largely deflected from the fair price specified. During the <span class="hlt">bubble</span>, brain regions associated with the cognitive processing that supports order decisions were identified. The asset preference that might bias the decision was associated with the ventrolateral prefrontal cortex and the dorsolateral prefrontal cortex (DLPFC). The activity of the inferior parietal lobule (IPL) was correlated with the score of future time perspective, which would bias the estimation of future price. These regions were deemed to form a distinctive network during the <span class="hlt">bubble</span>. A functional connectivity analysis showed that the connectivity between the DLPFC and the IPL was predominant compared with other connectivities only during the <span class="hlt">bubble</span>. These findings indicate that uncertain and unstable market conditions changed brain modes in traders. These brain mechanisms might lead to a loss of control caused by wishful thinking, and to microeconomic <span class="hlt">bubbles</span> that expand, on the macroscopic scale, toward bust. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1304725-bubble-skyrmion-crystals-frustrated-magnets-easy-axis-anisotropy','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1304725-bubble-skyrmion-crystals-frustrated-magnets-easy-axis-anisotropy"><span><span class="hlt">Bubble</span> and skyrmion crystals in frustrated magnets with easy-axis anisotropy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Hayami, Satoru; Lin, Shi-Zeng; Batista, Cristian D.</p> <p>2016-05-12</p> <p>We clarify the conditions for the emergence of multiple-Q structures out of lattice and easy-axis spin anisotropy in frustrated magnets. By considering magnets whose exchange interaction has multiple global minima in momentum space, we find that both types of anisotropy stabilize triple-Q orderings. Moderate anisotropy leads to a magnetic field-induced skyrmion crystal, which evolves into a <span class="hlt">bubble</span> crystal for increasing spatial and spin anisotropy. Finally, the <span class="hlt">bubble</span> crystal exhibits a quasi-continuous (devil’s staircase) temperature dependent ordering wave-vector, <span class="hlt">characteristic</span> of the competition between frustrated exchange and strong easy-axis anisotropy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AAS...22940408K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AAS...22940408K"><span>Subsonic evolution of the radio <span class="hlt">bubbles</span> in the nearby massive early-type galaxy NGC 4472: uplift, buoyancy, and heating</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kraft, Ralph P.; Gendron Marsolais, Marie-Lou; Bogdan, Akos; Su, Yuanyuan; Forman, William R.; Hlavacek-Larrondo, Julie; Jones, Christine; Nulsen, Paul; Randall, Scott W.; Roediger, Elke</p> <p>2017-01-01</p> <p>We present results from a deep (380 ks) Chandra observation of the hot gas in the nearby massive early-type galaxy NGC 4472. X-ray cavities were previously reported coincident with the radio lobes (Biller et al. 2004). In our deeper observation, we confirm the presence of the cavities and detect rims of enhanced emission surrounding the <span class="hlt">bubbles</span>. The temperature of the gas in these rims is less than that of the ambient medium, demonstrating that they cold, low entropy material that has been drawn up from the group center by the buoyant <span class="hlt">rise</span> of the <span class="hlt">bubbles</span> and not shocks from supersonic inflation of the lobes. Interestingly, the gravitational energy required to lift these lobes from the group center is a significant fraction of the <span class="hlt">bubble</span> enthalpy. This suggests that uplift by AGN <span class="hlt">bubbles</span> may play an important role in some cases in offsetting the radiative cooling at cluster and group centers. This uplift also provides an efficient means of transporting enriched material from the group center to large radii.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AmJPh..76.1087B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AmJPh..76.1087B"><span>Soap <span class="hlt">bubbles</span> in paintings: Art and science</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Behroozi, F.</p> <p>2008-12-01</p> <p>Soap <span class="hlt">bubbles</span> became popular in 17th century paintings and prints primarily as a metaphor for the impermanence and fragility of life. The Dancing Couple (1663) by the Dutch painter Jan Steen is a good example which, among many other symbols, shows a young boy blowing soap <span class="hlt">bubbles</span>. In the 18th century the French painter Jean-Simeon Chardin used soap <span class="hlt">bubbles</span> not only as metaphor but also to express a sense of play and wonder. In his most famous painting, Soap <span class="hlt">Bubbles</span> (1733/1734) a translucent and quavering soap <span class="hlt">bubble</span> takes center stage. Chardin's contemporary Charles Van Loo painted his Soap <span class="hlt">Bubbles</span> (1764) after seeing Chardin's work. In both paintings the soap <span class="hlt">bubbles</span> have a hint of color and show two bright reflection spots. We discuss the physics involved and explain how keenly the painters have observed the interaction of light and soap <span class="hlt">bubbles</span>. We show that the two reflection spots on the soap <span class="hlt">bubbles</span> are images of the light source, one real and one virtual, formed by the curved surface of the <span class="hlt">bubble</span>. The faint colors are due to thin film interference effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19739710','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19739710"><span>Influence of the <span class="hlt">bubble-bubble</span> interaction on destruction of encapsulated microbubbles under ultrasound.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yasui, Kyuichi; Lee, Judy; Tuziuti, Toru; Towata, Atsuya; Kozuka, Teruyuki; Iida, Yasuo</p> <p>2009-09-01</p> <p>Influence of the <span class="hlt">bubble-bubble</span> interaction on the pulsation of encapsulated microbubbles has been studied by numerical simulations under the condition of the experiment reported by Chang et al. [IEEE Trans. Ultrason Ferroelectr. Freq. Control 48, 161 (2001)]. It has been shown that the natural (resonance) frequency of a microbubble decreases considerably as the microbubble concentration increases to relatively high concentrations. At some concentration, the natural frequency may coincide with the driving frequency. Microbubble pulsation becomes milder as the microbubble concentration increases except at around the resonance condition due to the stronger <span class="hlt">bubble-bubble</span> interaction. This may be one of the reasons why the threshold of acoustic pressure for destruction of an encapsulated microbubble increases as the microbubble concentration increases. A theoretical model for destruction has been proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830000347&hterms=Glass+bubble&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGlass%2Bbubble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830000347&hterms=Glass+bubble&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGlass%2Bbubble"><span>Dissolving <span class="hlt">Bubbles</span> in Glass</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weinberg, M. C.; Oronato, P. I.; Uhlmann, D. R.</p> <p>1984-01-01</p> <p>Analytical expression used to calculate time it takes for stationary <span class="hlt">bubbles</span> of oxygen and carbon dioxide to dissolve from glass melt. Technique based on analytical expression for <span class="hlt">bubble</span> radius as function time, with consequences of surface tension included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16615794','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16615794"><span>Soap <span class="hlt">bubbles</span> in analytical chemistry. Conductometric determination of sub-parts per million levels of sulfur dioxide with a soap <span class="hlt">bubble</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kanyanee, Tinakorn; Borst, Walter L; Jakmunee, Jaroon; Grudpan, Kate; Li, Jianzhong; Dasgupta, Purnendu K</p> <p>2006-04-15</p> <p>Soap <span class="hlt">bubbles</span> provide a fascinating tool that is little used analytically. With a very low liquid volume to surface area ratio, a soap <span class="hlt">bubble</span> can potentially provide a very useful interface for preconcentration where mass transfer to an interfacial surface is important. Here we use an automated system to create <span class="hlt">bubbles</span> of uniform size and film thickness. We utilize purified Triton-X 100, a nonionic surfactant, to make soap <span class="hlt">bubbles</span>. We use such <span class="hlt">bubbles</span> as a gas-sampling interface. Incorporating hydrogen peroxide into the <span class="hlt">bubble</span> provides a system where electrical conductance increases as the <span class="hlt">bubble</span> is exposed to low concentrations of sulfur dioxide gas. We theoretically derive the conductance of a hollow conducting spherical thin film with spherical cap electrodes. We measure the film thickness by incorporating a dye in the <span class="hlt">bubble</span> making solution and laser transmission photometry and find that it agrees well with the geometrically computed thickness. With the conductance of the <span class="hlt">bubble</span>-making soap solution being measured by conventional methods, we show that the measured values of the <span class="hlt">bubble</span> conductance with known <span class="hlt">bubble</span> and electrode dimensions closely correspond to the theoretically computed value. Finally, we demonstrate that sub-ppm levels of SO(2) can readily be detected by the conductivity change of a hydrogen peroxide-doped soap <span class="hlt">bubble</span>, measured in situ, when the gas flows around the <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDG21009Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDG21009Z"><span>Effects of non-condensable gas on the dynamic oscillations of cavitation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Yuning</p> <p>2016-11-01</p> <p>Cavitation is an essential topic of multiphase flow with a broad range of applications. Generally, there exists non-condensable gas in the liquid and a complex vapor/gas mixture <span class="hlt">bubble</span> will be formed. A rigorous prediction of the dynamic behavior of the aforementioned mixture <span class="hlt">bubble</span> is essential for the development of a complete cavitation model. In the present paper, effects of non-condensable gas on the dynamic oscillations of the vapor/gas mixture <span class="hlt">bubble</span> are numerically investigated in great detail. For the completeness, a large parameter zone (e.g. <span class="hlt">bubble</span> radius, frequency and ratio between gas and vapor) is investigated with many demonstrating examples. The mechanisms of mass diffusion are categorized into different groups with their <span class="hlt">characteristics</span> and dominated regions given. Influences of non-condensable gas on the wave propagation (e.g. wave speed and attenuation) in the <span class="hlt">bubbly</span> liquids are also briefly discussed. Specifically, the minimum wave speed is quantitatively predicted in order to close the pressure-density coupling relationship usually employed for the cavitation modelling. Finally, the application of the present finding on the development of cavitation model is demonstrated with a brief discussion of its influence on the cavitation dynamics. This work was financially supported by the National Natural Science Foundation of China (Project No.: 51506051).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NuPhS.256..179C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NuPhS.256..179C"><span>Fermi <span class="hlt">bubbles</span> as a source of cosmic rays above 1015 eV</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chernyshov, D. O.; Cheng, K. S.; Dogiel, V. A.; Ko, C. M.</p> <p>2014-11-01</p> <p>Fermi <span class="hlt">bubbles</span> are giant gamma-ray structures extended north and south of the Galactic center with <span class="hlt">characteristic</span> sizes of order of 10 kpc recently discovered by Fermi Large Area Telescope. Good correlation between radio and gamma-ray emission in the region covered by Fermi <span class="hlt">bubbles</span> implies the presence of high-energy electrons in this region. Since it is relatively difficult for relativistic electrons of this energy to travel all the way from the Galactic sources toward Fermi <span class="hlt">bubbles</span> one can assume that they accelerated in-situ. The corresponding acceleration mechanism should also affect the distribution of the relativistic protons in the Galaxy. Since protons have much larger lifetimes the effect may even be observed near the Earth. In our model we suggest that Fermi <span class="hlt">bubbles</span> are created by acceleration of electrons on series of shocks born due to periodic star accretions by supermassive black hole Sgr A*. We propose that hadronic CR within the 'knee' of the observed CR spectrum are produced by Galactic supernova remnants distributed in the Galactic disk. Reacceleration of these particles in the Fermi <span class="hlt">Bubble</span> produces CRs beyond the knee. This model provides a natural explanation of the observed CR flux, spectral indexes, and matching of spectra at the knee.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16556197','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16556197"><span>Metaphors and models: the ASR <span class="hlt">bubble</span> in the Floridan aquifer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vacher, H L; Hutchings, William C; Budd, David A</p> <p>2006-01-01</p> <p>Studies at the intersection of cognitive science and linguistics have revealed the crucial role that metaphors play in shaping our thoughts about phenomena we cannot see. According to the domains interaction theory of cognition, a metaphoric expression sets up mappings between a target domain that we wish to understand and a familiar source domain. The source domain contains elements ("commonplaces") that we manipulate mentally, like parts of an analogue model, to illuminate the target domain. This paper applies the structure of domains interaction theory to analyze the dynamics of a metaphor in hydrogeology: the so-called <span class="hlt">bubble</span> formed by water injected into an aquifer during aquifer storage and recovery (ASR). Of the four commonplaces of <span class="hlt">bubbles</span>--(1) they are discrete; (2) they are geometrically simple; (3) they <span class="hlt">rise</span>; and (4) they burst--we focus on the first two using both displacement and dispersion (tracer) models for both homogeneous and heterogeneous storage zones patterned from geological studies of the Suwannee Limestone of Sarasota County, Florida. The displacement model easily shows that "bottle brush" better represents the geometric complexity predicted from the known and inferred heterogeneity. There is virtually no difference, however, in the prediction of recovery efficiency using the dispersion model for a <span class="hlt">bubble</span> (homogeneous flow zone) vs. bottle brush (heterogeneous flow zone). On the other hand, only the bottle brush reveals that unrecovered tracer is located preferentially in the low-permeability layers that lie adjacent to high-permeability channels in the flow zones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820015565','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820015565"><span>The production of drops by the bursting of a <span class="hlt">bubble</span> at an air liquid interface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Darrozes, J. S.; Ligneul, P.</p> <p>1982-01-01</p> <p>The fundamental mechanism arising during the bursting of a <span class="hlt">bubble</span> at an air-liquid interface is described. A single <span class="hlt">bubble</span> was followed from an arbitrary depth in the liquid, up to the creation and motion of the film and jet drops. Several phenomena were involved and their relative order of magnitude was compared in order to point out the dimensionless parameters which govern each step of the motion. High-speed cinematography is employed. The <span class="hlt">characteristic</span> <span class="hlt">bubble</span> radius which separates the creation of jet drops from cap bursting without jet drops is expressed mathematically. The corresponding numerical value for water is 3 mm and agrees with experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24580324','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24580324"><span>Unorthodox <span class="hlt">bubbles</span> when boiling in cold water.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Parker, Scott; Granick, Steve</p> <p>2014-01-01</p> <p>High-speed movies are taken when <span class="hlt">bubbles</span> grow at gold surfaces heated spotwise with a near-infrared laser beam heating water below the boiling point (60-70 °C) with heating powers spanning the range from very low to so high that water fails to rewet the surface after <span class="hlt">bubbles</span> detach. Roughly half the <span class="hlt">bubbles</span> are conventional: They grow symmetrically through evaporation until buoyancy lifts them away. Others have unorthodox shapes and appear to contribute disproportionately to heat transfer efficiency: mushroom cloud shapes, violently explosive <span class="hlt">bubbles</span>, and cavitation events, probably stimulated by a combination of superheating, convection, turbulence, and surface dewetting during the initial <span class="hlt">bubble</span> growth. Moreover, <span class="hlt">bubbles</span> often follow one another in complex sequences, often beginning with an unorthodox <span class="hlt">bubble</span> that stirs the water, followed by several conventional <span class="hlt">bubbles</span>. This large dataset is analyzed and discussed with emphasis on how explosive phenomena such as cavitation induce discrepancies from classical expectations about boiling.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFD.G4008D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFD.G4008D"><span>Pinch-off Scaling Law of Soap <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davidson, John; Ryu, Sangjin</p> <p>2014-11-01</p> <p>Three common interfacial phenomena that occur daily are liquid drops in gas, gas <span class="hlt">bubbles</span> in liquid and thin-film <span class="hlt">bubbles</span>. One aspect that has been studied for these phenomena is the formation or pinch-off of the drop/<span class="hlt">bubble</span> from the liquid/gas threads. In contrast to the formation of liquid drops in gas and gas <span class="hlt">bubbles</span> in liquid, thin-film <span class="hlt">bubble</span> pinch-off has not been well documented. Having thin-film interfaces may alter the pinch-off process due to the limiting factor of the film thickness. We observed the pinch-off of one common thin-film <span class="hlt">bubble</span>, soap <span class="hlt">bubbles</span>, in order to characterize its pinch-off behavior. We achieved this by constructing an experimental model replicating the process of a human producing soap <span class="hlt">bubbles</span>. Using high-speed videography and image processing, we determined that the minimal neck radius scaled with the time left till pinch-off, and that the scaling law exponent was 2/3, similar to that of liquid drops in gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA629693','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA629693"><span><span class="hlt">Bubbles</span> in Sediments</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1999-09-30</p> <p>saturated poroelastic medium. The transition matrix scattering formalism was used to develop the scattered acoustic field(s) such that appropriate...sediment increases from a fluid model (simplest) to a fluid-saturated poroelastic model (most complex). Laboratory experiments in carefully quantified...of a linear acoustic field from a <span class="hlt">bubble</span>, collection of <span class="hlt">bubbles</span>, or other targets embedded in a fluid-saturated sediment are not well known. This</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26442143','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26442143"><span><span class="hlt">Bubbles</span> with shock waves and ultrasound: a review.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ohl, Siew-Wan; Klaseboer, Evert; Khoo, Boo Cheong</p> <p>2015-10-06</p> <p>The study of the interaction of <span class="hlt">bubbles</span> with shock waves and ultrasound is sometimes termed 'acoustic cavitation'. It is of importance in many biomedical applications where sound waves are applied. The use of shock waves and ultrasound in medical treatments is appealing because of their non-invasiveness. In this review, we present a variety of acoustics-<span class="hlt">bubble</span> interactions, with a focus on shock wave-<span class="hlt">bubble</span> interaction and <span class="hlt">bubble</span> cloud phenomena. The dynamics of a single spherically oscillating <span class="hlt">bubble</span> is rather well understood. However, when there is a nearby surface, the <span class="hlt">bubble</span> often collapses non-spherically with a high-speed jet. The direction of the jet depends on the 'resistance' of the boundary: the <span class="hlt">bubble</span> jets towards a rigid boundary, splits up near an elastic boundary, and jets away from a free surface. The presence of a shock wave complicates the <span class="hlt">bubble</span> dynamics further. We shall discuss both experimental studies using high-speed photography and numerical simulations involving shock wave-<span class="hlt">bubble</span> interaction. In biomedical applications, instead of a single <span class="hlt">bubble</span>, often clouds of <span class="hlt">bubbles</span> appear (consisting of many individual <span class="hlt">bubbles</span>). The dynamics of such a <span class="hlt">bubble</span> cloud is even more complex. We shall show some of the phenomena observed in a high-intensity focused ultrasound (HIFU) field. The nonlinear nature of the sound field and the complex inter-<span class="hlt">bubble</span> interaction in a cloud present challenges to a comprehensive understanding of the physics of the <span class="hlt">bubble</span> cloud in HIFU. We conclude the article with some comments on the challenges ahead.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4549845','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4549845"><span><span class="hlt">Bubbles</span> with shock waves and ultrasound: a review</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ohl, Siew-Wan; Klaseboer, Evert; Khoo, Boo Cheong</p> <p>2015-01-01</p> <p>The study of the interaction of <span class="hlt">bubbles</span> with shock waves and ultrasound is sometimes termed ‘acoustic cavitation'. It is of importance in many biomedical applications where sound waves are applied. The use of shock waves and ultrasound in medical treatments is appealing because of their non-invasiveness. In this review, we present a variety of acoustics–<span class="hlt">bubble</span> interactions, with a focus on shock wave–<span class="hlt">bubble</span> interaction and <span class="hlt">bubble</span> cloud phenomena. The dynamics of a single spherically oscillating <span class="hlt">bubble</span> is rather well understood. However, when there is a nearby surface, the <span class="hlt">bubble</span> often collapses non-spherically with a high-speed jet. The direction of the jet depends on the ‘resistance' of the boundary: the <span class="hlt">bubble</span> jets towards a rigid boundary, splits up near an elastic boundary, and jets away from a free surface. The presence of a shock wave complicates the <span class="hlt">bubble</span> dynamics further. We shall discuss both experimental studies using high-speed photography and numerical simulations involving shock wave–<span class="hlt">bubble</span> interaction. In biomedical applications, instead of a single <span class="hlt">bubble</span>, often clouds of <span class="hlt">bubbles</span> appear (consisting of many individual <span class="hlt">bubbles</span>). The dynamics of such a <span class="hlt">bubble</span> cloud is even more complex. We shall show some of the phenomena observed in a high-intensity focused ultrasound (HIFU) field. The nonlinear nature of the sound field and the complex inter-<span class="hlt">bubble</span> interaction in a cloud present challenges to a comprehensive understanding of the physics of the <span class="hlt">bubble</span> cloud in HIFU. We conclude the article with some comments on the challenges ahead. PMID:26442143</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.5868W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.5868W"><span>Predawn plasma <span class="hlt">bubble</span> cluster observed in Southeast Asia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watthanasangmechai, Kornyanat; Yamamoto, Mamoru; Saito, Akinori; Tsunoda, Roland; Yokoyama, Tatsuhiro; Supnithi, Pornchai; Ishii, Mamoru; Yatini, Clara</p> <p>2016-06-01</p> <p>Predawn plasma <span class="hlt">bubble</span> was detected as deep plasma depletion by GNU Radio Beacon Receiver (GRBR) network and in situ measurement onboard Defense Meteorological Satellite Program F15 (DMSPF15) satellite and was confirmed by sparse GPS network in Southeast Asia. In addition to the deep depletion, the GPS network revealed the coexisting submesoscale irregularities. A deep depletion is regarded as a primary <span class="hlt">bubble</span>. Submesoscale irregularities are regarded as secondary <span class="hlt">bubbles</span>. Primary <span class="hlt">bubble</span> and secondary <span class="hlt">bubbles</span> appeared together as a cluster with zonal wavelength of 50 km. An altitude of secondary <span class="hlt">bubbles</span> happened to be lower than that of the primary <span class="hlt">bubble</span> in the same cluster. The observed pattern of plasma <span class="hlt">bubble</span> cluster is consistent with the simulation result of the recent high-resolution <span class="hlt">bubble</span> (HIRB) model. This event is only a single event out of 76 satellite passes at nighttime during 3-25 March 2012 that significantly shows plasma depletion at plasma <span class="hlt">bubble</span> wall. The inside structure of the primary <span class="hlt">bubble</span> was clearly revealed from the in situ density data of DMSPF15 satellite and the ground-based GRBR total electron content.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820000341&hterms=Glass+bubble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DGlass%2Bbubble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820000341&hterms=Glass+bubble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DGlass%2Bbubble"><span>Acoustic Methods Remove <span class="hlt">Bubbles</span> From Liquids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Trinh, E.; Elleman, D. D.; Wang, T. G.</p> <p>1983-01-01</p> <p>Two acoustic methods applied to molten glass or other viscous liquids to remove <span class="hlt">bubbles</span>. <span class="hlt">Bubbles</span> are either absorbed or brought to surface by applying high-intensity Sonic field at resonant frequency. Sonic oscillation increases surface area of <span class="hlt">bubbles</span> and causes them to dissipate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPJWC.14009002P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPJWC.14009002P"><span>Influence of obstacles on <span class="hlt">bubbles</span> <span class="hlt">rising</span> in water-saturated sand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poryles, Raphaël; Varas, Germán; Vidal, Valérie</p> <p>2017-06-01</p> <p>This work investigates the dynamics of air <span class="hlt">rising</span> through a water-saturated sand confined in a Hele- Shaw cell in which a circular obstacle is trapped. The air is injected at constant flow rate through a single nozzle at the bottom center of the cell. Without obstacle, in a similar configuration, previous studies pointed out the existence of a fluidized zone generated by the central upward gas motion which entrains two granular convection rolls on its sides. Here, a circular obstacle which diameter is of the order of the central air channel width is trapped at the vertical of the injection nozzle. We analyze the influence of the obstacle location on the size of the fluidized zone and its impact on the morphology of the central air channel. Finally, we quantify the variations of the granular free surface. Two configurations with multiple obstacles are also considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22078340','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22078340"><span>Mesoporous hollow spheres from soap <span class="hlt">bubbling</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Xianglin; Liang, Fuxin; Liu, Jiguang; Lu, Yunfeng; Yang, Zhenzhong</p> <p>2012-02-01</p> <p>The smaller and more stable <span class="hlt">bubbles</span> can be generated from the large parent <span class="hlt">bubbles</span> by rupture. In the presence of a <span class="hlt">bubble</span> blowing agent, hollow spheres can be prepared by <span class="hlt">bubbling</span> a silica sol. Herein, the trapped gas inside the <span class="hlt">bubble</span> acts as a template. When the porogen, i.e., other surfactant, is introduced, a mesostructured shell forms by the co-assembly with the silica sol during sol-gel process. Morphological evolution emphasizes the prerequisite of an intermediate interior gas flow rate and high exterior gas flow rate for hollow spheres. The method is valid for many compositions from inorganic, polymer to their composites. Copyright © 2011 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/866790','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/866790"><span>Rotating <span class="hlt">bubble</span> membrane radiator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Webb, Brent J.; Coomes, Edmund P.</p> <p>1988-12-06</p> <p>A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating <span class="hlt">bubble</span> membrane radiator, where it is sprayed into the interior of the <span class="hlt">bubble</span>. Liquid impacting upon the interior surface of the <span class="hlt">bubble</span> is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100042226','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100042226"><span>Slopes To Prevent Trapping of <span class="hlt">Bubbles</span> in Microfluidic Channels</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Greer, Harold E.; Lee, Michael C.; Smith, J. Anthony; Willis, Peter A.</p> <p>2010-01-01</p> <p>The idea of designing a microfluidic channel to slope upward along the direction of flow of the liquid in the channel has been conceived to help prevent trapping of gas <span class="hlt">bubbles</span> in the channel. In the original application that gave <span class="hlt">rise</span> to this idea, the microfluidic channels are parts of micro-capillary electrophoresis (microCE) devices undergoing development for use on Mars in detecting compounds indicative of life. It is necessary to prevent trapping of gas <span class="hlt">bubbles</span> in these devices because uninterrupted liquid pathways are essential for sustaining the electrical conduction and flows that are essential for CE. The idea is also applicable to microfluidic devices that may be developed for similar terrestrial microCE biotechnological applications or other terrestrial applications in which trapping of <span class="hlt">bubbles</span> in microfluidic channels cannot be tolerated. A typical microCE device in the original application includes, among other things, multiple layers of borosilicate float glass wafers. Microfluidic channels are formed in the wafers, typically by use of wet chemical etching. The figure presents a simplified cross section of part of such a device in which the CE channel is formed in the lowermost wafer (denoted the channel wafer) and, according to the present innovation, slopes upward into a via hole in another wafer (denoted the manifold wafer) lying immediately above the channel wafer. Another feature of the present innovation is that the via hole in the manifold wafer is made to taper to a wider opening at the top to further reduce the tendency to trap <span class="hlt">bubbles</span>. At the time of reporting the information for this article, an effort to identify an optimum technique for forming the slope and the taper was in progress. Of the techniques considered thus far, the one considered to be most promising is precision milling by use of femtosecond laser pulses. Other similar techniques that may work equally well are precision milling using a focused ion beam, or a small diamond</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...619113R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...619113R"><span>Surfactants for <span class="hlt">Bubble</span> Removal against Buoyancy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raza, Md. Qaisar; Kumar, Nirbhay; Raj, Rishi</p> <p>2016-01-01</p> <p>The common phenomenon of buoyancy-induced vapor <span class="hlt">bubble</span> lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing <span class="hlt">bubbles</span> coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted heater in earth gravity where both buoyancy and surface tension act upwards to oppose <span class="hlt">bubble</span> removal. Here we report a robust passive technique which uses surfactants found in common soaps and detergents to avoid coalescence and remove <span class="hlt">bubbles</span> downwards, away from an inverted heater. A force balance model is developed to demonstrate that the force of repulsion resulting from the interaction of surfactants adsorbed at the neighboring liquid-vapor interfaces of the thin liquid film contained between <span class="hlt">bubbles</span> is strong enough to overcome buoyancy and surface tension. <span class="hlt">Bubble</span> removal frequencies in excess of ten Hz resulted in more than twofold enhancement in heat transfer in comparison to pure water. We believe that this novel <span class="hlt">bubble</span> removal mechanism opens up opportunities for designing boiling-based systems for space applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4705484','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4705484"><span>Surfactants for <span class="hlt">Bubble</span> Removal against Buoyancy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Raza, Md. Qaisar; Kumar, Nirbhay; Raj, Rishi</p> <p>2016-01-01</p> <p>The common phenomenon of buoyancy-induced vapor <span class="hlt">bubble</span> lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing <span class="hlt">bubbles</span> coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted heater in earth gravity where both buoyancy and surface tension act upwards to oppose <span class="hlt">bubble</span> removal. Here we report a robust passive technique which uses surfactants found in common soaps and detergents to avoid coalescence and remove <span class="hlt">bubbles</span> downwards, away from an inverted heater. A force balance model is developed to demonstrate that the force of repulsion resulting from the interaction of surfactants adsorbed at the neighboring liquid-vapor interfaces of the thin liquid film contained between <span class="hlt">bubbles</span> is strong enough to overcome buoyancy and surface tension. <span class="hlt">Bubble</span> removal frequencies in excess of ten Hz resulted in more than twofold enhancement in heat transfer in comparison to pure water. We believe that this novel <span class="hlt">bubble</span> removal mechanism opens up opportunities for designing boiling-based systems for space applications. PMID:26743179</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810000292&hterms=Glass+bubble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DGlass%2Bbubble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810000292&hterms=Glass+bubble&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DGlass%2Bbubble"><span>Gas Diffusion in Fluids Containing <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zak, M.; Weinberg, M. C.</p> <p>1982-01-01</p> <p>Mathematical model describes movement of gases in fluid containing many <span class="hlt">bubbles</span>. Model makes it possible to predict growth and shrink age of <span class="hlt">bubbles</span> as function of time. New model overcomes complexities involved in analysis of varying conditions by making two simplifying assumptions. It treats <span class="hlt">bubbles</span> as point sources, and it employs approximate expression for gas concentration gradient at liquid/<span class="hlt">bubble</span> interface. In particular, it is expected to help in developing processes for production of high-quality optical glasses in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28528785','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28528785"><span>Resonance Tube Phonation in Water-the Effect of Tube Diameter and Water Depth on Back Pressure and <span class="hlt">Bubble</span> <span class="hlt">Characteristics</span> at Different Airflows.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wistbacka, Greta; Andrade, Pedro Amarante; Simberg, Susanna; Hammarberg, Britta; Södersten, Maria; Švec, Jan G; Granqvist, Svante</p> <p>2018-01-01</p> <p>Resonance tube phonation with tube end in water is a voice therapy method in which the patient phonates through a glass tube, keeping the free end of the tube submerged in water, creating <span class="hlt">bubbles</span>. The purpose of this experimental study was to determine flow-pressure relationship, flow thresholds between <span class="hlt">bubble</span> types, and <span class="hlt">bubble</span> frequency as a function of flow and back volume. A flow-driven vocal tract simulator was used for recording the back pressure produced by resonance tubes with inner diameters of 8 and 9 mm submerged at water depths of 0-7 cm. Visual inspection of <span class="hlt">bubble</span> types through video recording was also performed. The static back pressure was largely determined by the water depth. The narrower tube provided a slightly higher back pressure for a given flow and depth. The amplitude of the pressure oscillations increased with flow and depth. Depending on flow, the <span class="hlt">bubbles</span> were emitted from the tube in three distinct types with increasing flow: one by one, pairwise, and in a chaotic manner. The <span class="hlt">bubble</span> frequency was slightly higher for the narrower tube. An increase in back volume led to a decrease in <span class="hlt">bubble</span> frequency. This study provides data on the physical properties of resonance tube phonation with the tube end in water. This information will be useful in future research when looking into the possible effects of this type of voice training. Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28531363','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28531363"><span>Beneficial effect of enriched air nitrox on <span class="hlt">bubble</span> formation during scuba diving. An open-water study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brebeck, Anne-Kathrin; Deussen, Andreas; Range, Ursula; Balestra, Costantino; Cleveland, Sinclair; Schipke, Jochen D</p> <p>2018-03-01</p> <p><span class="hlt">Bubble</span> formation during scuba diving might induce decompression sickness. This prospective randomised and double-blind study included 108 advanced recreational divers (38 females). Fifty-four pairs of divers, 1 breathing air and the other breathing nitrox28 undertook a standardised dive (24 ± 1 msw; 62 ± 5min) in the Red Sea. Venous gas <span class="hlt">bubbles</span> were counted (Doppler) 30-<45 min (early) and 45-60 min (late) post-dive at jugular, subclavian and femoral sites. Only 7% (air) vs. 11% (air28®) (n.s.) were <span class="hlt">bubble</span>-free after a dive. Independent of sampling time and breathing gas, there were more <span class="hlt">bubbles</span> in the jugular than in the femoral vein. More <span class="hlt">bubbles</span> were counted in the air-group than in the air28-group (pooled vein: early: 1845 vs. 948; P = 0.047, late: 1817 vs. 953; P = 0.088). The number of <span class="hlt">bubbles</span> was sex-dependent. Lastly, 29% of female air divers but only 14% of male divers were <span class="hlt">bubble</span>-free (P = 0.058). Air28® helps to reduce venous gas emboli in recreational divers. The <span class="hlt">bubble</span> number depended on the breathing gas, sampling site and sex. Thus, both exact reporting the dive and in particular standardising sampling <span class="hlt">characteristics</span> seem mandatory to compare results from different studies to further investigate the hitherto incoherent relation between inert gas <span class="hlt">bubbles</span> and DCS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21428629-oh-production-enhancement-bubbling-pulsed-discharges','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21428629-oh-production-enhancement-bubbling-pulsed-discharges"><span>OH Production Enhancement in <span class="hlt">Bubbling</span> Pulsed Discharges</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lungu, Cristian P.; Porosnicu, Corneliu; Jepu, Ionut</p> <p>2010-10-13</p> <p>The generation of active species, such as H{sub 2}O{sub 2}, O{sup *}, OH*, HO{sub 2}*, O{sub 3}, N{sub 2}{sup *}, etc, produced in aqueous solutions by HV pulsed discharges was studied in order to find the most efficient way in waste water treatment taking into account that these species are almost stronger oxidizers than ozone. Plasma was generated inside gas <span class="hlt">bubbles</span> formed by the argon, air and oxygen gas flow between the special designed electrodes. The pulse width and pulse frequency influence was studied in order to increase the efficiency of the OH active species formation. The produced active speciesmore » were investigated by optical emission spectroscopy and correlated with electrical parameters of the discharges (frequency, pulse width, amplitude, and <span class="hlt">rise</span> and decay time).« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5298746','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5298746"><span>Two-Dimensional Numerical Simulations of Ultrasound in Liquids with Gas <span class="hlt">Bubble</span> Agglomerates: Examples of <span class="hlt">Bubbly</span>-Liquid-Type Acoustic Metamaterials (BLAMMs)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vanhille, Christian</p> <p>2017-01-01</p> <p>This work deals with a theoretical analysis about the possibility of using linear and nonlinear acoustic properties to modify ultrasound by adding gas <span class="hlt">bubbles</span> of determined sizes in a liquid. We use a two-dimensional numerical model to evaluate the effect that one and several monodisperse <span class="hlt">bubble</span> populations confined in restricted areas of a liquid have on ultrasound by calculating their nonlinear interaction. The filtering of an input ultrasonic pulse performed by a net of <span class="hlt">bubbly</span>-liquid cells is analyzed. The generation of a low-frequency component from a single cell impinged by a two-frequency harmonic wave is also studied. These effects rely on the particular dispersive character of attenuation and nonlinearity of such <span class="hlt">bubbly</span> fluids, which can be extremely high near <span class="hlt">bubble</span> resonance. They allow us to observe how gas <span class="hlt">bubbles</span> can change acoustic signals. Variations of the <span class="hlt">bubbly</span> medium parameters induce alterations of the effects undergone by ultrasound. Results suggest that acoustic signals can be manipulated by <span class="hlt">bubbles</span>. This capacity to achieve the modification and control of sound with oscillating gas <span class="hlt">bubbles</span> introduces the concept of <span class="hlt">bubbly</span>-liquid-based acoustic metamaterials (BLAMMs). PMID:28106748</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28106748','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28106748"><span>Two-Dimensional Numerical Simulations of Ultrasound in Liquids with Gas <span class="hlt">Bubble</span> Agglomerates: Examples of <span class="hlt">Bubbly</span>-Liquid-Type Acoustic Metamaterials (BLAMMs).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vanhille, Christian</p> <p>2017-01-17</p> <p>This work deals with a theoretical analysis about the possibility of using linear and nonlinear acoustic properties to modify ultrasound by adding gas <span class="hlt">bubbles</span> of determined sizes in a liquid. We use a two-dimensional numerical model to evaluate the effect that one and several monodisperse <span class="hlt">bubble</span> populations confined in restricted areas of a liquid have on ultrasound by calculating their nonlinear interaction. The filtering of an input ultrasonic pulse performed by a net of <span class="hlt">bubbly</span>-liquid cells is analyzed. The generation of a low-frequency component from a single cell impinged by a two-frequency harmonic wave is also studied. These effects rely on the particular dispersive character of attenuation and nonlinearity of such <span class="hlt">bubbly</span> fluids, which can be extremely high near <span class="hlt">bubble</span> resonance. They allow us to observe how gas <span class="hlt">bubbles</span> can change acoustic signals. Variations of the <span class="hlt">bubbly</span> medium parameters induce alterations of the effects undergone by ultrasound. Results suggest that acoustic signals can be manipulated by <span class="hlt">bubbles</span>. This capacity to achieve the modification and control of sound with oscillating gas <span class="hlt">bubbles</span> introduces the concept of <span class="hlt">bubbly</span>-liquid-based acoustic metamaterials (BLAMMs).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F7002P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F7002P"><span>The life and death of film <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poulain, S.; Villermaux, E.; Bourouiba, L.</p> <p>2017-11-01</p> <p>Following its burst, the fragmentation of a large <span class="hlt">bubble</span> (film <span class="hlt">bubble</span>) at the air-water interface can release hundreds of micrometer-sized film-drops in the air we breathe. This mechanism of droplet formation is one of the most prominent sources of sea spray. Indoor or outdoor, pathogens from contaminated water are transported by these droplets and have also been linked to respiratory infection. The lifetime and thickness of <span class="hlt">bubbles</span> govern the number and size of the droplets they produce. Despite these important implications, little is known about the factors influencing the life and death of surface film <span class="hlt">bubbles</span>. In particular, the fundamental physical mechanisms linking <span class="hlt">bubble</span> aging, thinning, and lifetime remain poorly understood. To address this gap, we present the results of an extensive investigation of the aging of film-drop-producing <span class="hlt">bubbles</span> in various ambient air, water composition, and temperature conditions. We present and validate a generalized physical picture and model of <span class="hlt">bubble</span> cap thickness evolution. The model and physical picture are linked to the lifetime of <span class="hlt">bubbles</span> via a series of cap rupture mechanisms of increasing efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AmJPh..78..990J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AmJPh..78..990J"><span>Analysis of a deflating soap <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jackson, David P.; Sleyman, Sarah</p> <p>2010-10-01</p> <p>A soap <span class="hlt">bubble</span> on the end of a cylindrical tube is seen to deflate as the higher pressure air inside the <span class="hlt">bubble</span> escapes through a tube. We perform an experiment to measure the radius of the slowly deflating <span class="hlt">bubble</span> and observe that the radius decreases to a minimum before quickly increasing. This behavior reflects the fact that the <span class="hlt">bubble</span> ends up as a flat surface over the end of the tube. A theoretical analysis reproduces this behavior and compares favorably with the experimental data.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvF...3a3302Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvF...3a3302Z"><span>Steady displacement of long gas <span class="hlt">bubbles</span> in channels and tubes filled by a Bingham fluid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zamankhan, Parsa; Takayama, Shuichi; Grotberg, James B.</p> <p>2018-01-01</p> <p>Bingham fluids behave like solids below a von Mises stress threshold, the yield stress, while above it they behave like Newtonian fluids. They are characterized by a dimensionless parameter, Bingham number (Bn), which is the ratio of the yield stress to a <span class="hlt">characteristic</span> viscous stress. In this study, the noninertial steady motion of a finite-size gas <span class="hlt">bubble</span> in both a plane two-dimensional (2D) channel and an axisymmetric tube filled by a Bingham fluid has been studied numerically. The Bingham number, Bn, is in the range 0 ≤Bn ≤3 , where Bn =0 is the Newtonian case, while the capillary number, which is the ratio of a <span class="hlt">characteristic</span> viscous force to the surface tension, has values Ca =0.05 ,0.10 , and 0.25. The volume of all axisymmetric and 2D <span class="hlt">bubbles</span> has been chosen to be identical for all parameter choices and large enough for the <span class="hlt">bubbles</span> to be long compared to the channel, tube height, and diameter. The Bingham fluid constitutive equation is approximated by a regularized equation. During the motion, the <span class="hlt">bubble</span> interface is separated from the wall by a static liquid film. The film thickness scaled by the tube radius (axisymmetric) and half of the channel height (2D) is the dimensionless film thickness, h . The results show that increasing Bn initially leads to an increase in h ; however, the profile h versus Bn can be monotonic or nonmonotonic depending on Ca values and 2D or axisymmetric configurations. The yield stress also alters the shape of the front and rear of the <span class="hlt">bubble</span> and suppresses the capillary waves at the rear of the <span class="hlt">bubble</span>. The yield stress increases the magnitude of the wall shear stress and its gradient and therefore increases the potential for epithelial cell injuries in applications to lung airway mucus plugs. The topology of the yield surfaces as well as the flow pattern in the <span class="hlt">bubble</span> frame of reference varies significantly by Ca and Bn.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999APS..DFD..AJ03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999APS..DFD..AJ03K"><span>Transient <span class="hlt">bubbles</span>, bublets and breakup</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keen, Giles; Blake, John</p> <p>1999-11-01</p> <p>The non-spherical nature of the collapse of <span class="hlt">bubbles</span> has important ramifications in many practical situations such as ultrasonic cleaning, tanning of leather, and underwater explosions. In particular the high speed liquid jet that can thread a collapsing <span class="hlt">bubble</span> is central to the functional performance. An impressive photographic record of a liquid jet was obtained by Crum using a <span class="hlt">bubble</span> situated in the vicinity of a platform oscillating vertically at a frequency of 60 Hz. A boundary integral method is used to model this situation and is found to closely mimic some of the observations. However, a slight variation of parameters or a change in the phase of the driving frequency can lead to dramatically different <span class="hlt">bubble</span> behaviour, a feature also observed by Crum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22676215-electroweak-bubble-wall-speed-limit','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22676215-electroweak-bubble-wall-speed-limit"><span>Electroweak <span class="hlt">bubble</span> wall speed limit</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Bödeker, Dietrich; Moore, Guy D., E-mail: bodeker@physik.uni-bielefeld.de, E-mail: guymoore@ikp.physik.tu-darmstadt.de</p> <p></p> <p>In extensions of the Standard Model with extra scalars, the electroweak phase transition can be very strong, and the <span class="hlt">bubble</span> walls can be highly relativistic. We revisit our previous argument that electroweak <span class="hlt">bubble</span> walls can 'run away,' that is, achieve extreme ultrarelativistic velocities γ ∼ 10{sup 14}. We show that, when particles cross the <span class="hlt">bubble</span> wall, they can emit transition radiation. Wall-frame soft processes, though suppressed by a power of the coupling α, have a significance enhanced by the γ-factor of the wall, limiting wall velocities to γ ∼ 1/α. Though the <span class="hlt">bubble</span> walls can move at almost the speedmore » of light, they carry an infinitesimal share of the plasma's energy.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=optics+AND+interference&pg=2&id=EJ374049','ERIC'); return false;" href="https://eric.ed.gov/?q=optics+AND+interference&pg=2&id=EJ374049"><span>Let Them Blow <span class="hlt">Bubbles</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Korenic, Eileen</p> <p>1988-01-01</p> <p>Describes a series of activities and demonstrations involving the science of soap <span class="hlt">bubbles</span>. Starts with a recipe for <span class="hlt">bubble</span> solution and gives instructions for several activities on topics such as density, interference colors, optics, static electricity, and galaxy formation. Contains some background information to help explain some of the effects.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFD.R4004G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFD.R4004G"><span><span class="hlt">Bubble</span> formation dynamics in a planar co-flow configuration: Influence of geometric and operating <span class="hlt">characteristics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gutiérrez-Montes, Cándido; Bolaños-Jiménez, Rocío; Martínez-Bazán, Carlos; Sevilla, Alejandro</p> <p>2014-11-01</p> <p>An experimental and numerical study has been performed to explore the influence of different geometric features and operating conditions on the dynamics of a water-air-water planar co-flow. Specifically, regarding the nozzle used, the inner-to-outer thickness ratio of the air injector, β = Hi/Ho, the water-to-air thickness ratio, h = Hw/Ho, and the shape of the injector tip, have been described. As for the operating conditions, the water exit velocity profile under constant flow rate and constant air feeding pressure has been assessed. The results show that the jetting-<span class="hlt">bubbling</span> transition is promoted for increasing values of β, decreasing values of h, rounded injector tip, and for uniform water exit velocity profiles. As for the <span class="hlt">bubble</span> formation frequency, it increases with increasing values of β, decreasing values of h, rounded injector and parabolic-shaped water exit profiles. Furthermore, the <span class="hlt">bubble</span> formation frequency has been shown to be lower under constant air feeding pressure conditions than at constant gas flow rate conditions. Finally, the effectiveness of a time-variable air feeding stream has been numerically studied, determining the forcing receptivity space in the amplitude-frequency plane. Experimental results corroborate the effectiveness of this control technique. Work supported by Spanish MINECO, Junta de Andalucía, European Funds and UJA under Projects DPI2011-28356-C03-02, DPI2011-28356-C03-03, P11-TEP7495 and UJA2013/08/05.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvF...3c4306S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvF...3c4306S"><span>Average properties of bidisperse <span class="hlt">bubbly</span> flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Serrano-García, J. C.; Mendez-Díaz, S.; Zenit, R.</p> <p>2018-03-01</p> <p>Experiments were performed in a vertical channel to study the properties of a <span class="hlt">bubbly</span> flow composed of two distinct <span class="hlt">bubble</span> size species. <span class="hlt">Bubbles</span> were produced using a capillary bank with tubes with two distinct inner diameters; the flow through each capillary size was controlled such that the amount of large or small <span class="hlt">bubbles</span> could be controlled. Using water and water-glycerin mixtures, a wide range of Reynolds and Weber number ranges were investigated. The gas volume fraction ranged between 0.5% and 6%. The measurements of the mean <span class="hlt">bubble</span> velocity of each species and the liquid velocity variance were obtained and contrasted with the monodisperse flows with equivalent gas volume fractions. We found that the bidispersity can induce a reduction of the mean <span class="hlt">bubble</span> velocity of the large species; for the small size species, the <span class="hlt">bubble</span> velocity can be increased, decreased, or remain unaffected depending of the flow conditions. The liquid velocity variance of the bidisperse flows is, in general, bound by the values of the small and large monodisperse values; interestingly, in some cases, the liquid velocity fluctuations can be larger than either monodisperse case. A simple model for the liquid agitation for bidisperse flows is proposed, with good agreement with the experimental measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25771332','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25771332"><span>Influences of non-uniform pressure field outside <span class="hlt">bubbles</span> on the propagation of acoustic waves in dilute <span class="hlt">bubbly</span> liquids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Yuning; Du, Xiaoze</p> <p>2015-09-01</p> <p>Predictions of the propagation of the acoustic waves in <span class="hlt">bubbly</span> liquids is of great importance for <span class="hlt">bubble</span> dynamics and related applications (e.g. sonochemistry, sonochemical reactor design, biomedical engineering). In the present paper, an approach for modeling the propagation of the acoustic waves in dilute <span class="hlt">bubbly</span> liquids is proposed through considering the non-uniform pressure field outside the <span class="hlt">bubbles</span>. This approach is validated through comparing with available experimental data in the literature. Comparing with the previous models, our approach mainly improves the predictions of the attenuation of acoustic waves in the regions with large kR0 (k is the wave number and R0 is the equilibrium <span class="hlt">bubble</span> radius). Stability of the oscillating <span class="hlt">bubbles</span> under acoustic excitation are also quantitatively discussed based on the analytical solution. Copyright © 2015 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12636582','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12636582"><span>Bifurcation scenarios for <span class="hlt">bubbling</span> transition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zimin, Aleksey V; Hunt, Brian R; Ott, Edward</p> <p>2003-01-01</p> <p>Dynamical systems with chaos on an invariant submanifold can exhibit a type of behavior called <span class="hlt">bubbling</span>, whereby a small random or fixed perturbation to the system induces intermittent bursting. The bifurcation to <span class="hlt">bubbling</span> occurs when a periodic orbit embedded in the chaotic attractor in the invariant manifold becomes unstable to perturbations transverse to the invariant manifold. Generically the periodic orbit can become transversely unstable through a pitchfork, transcritical, period-doubling, or Hopf bifurcation. In this paper a unified treatment of the four types of <span class="hlt">bubbling</span> bifurcation is presented. Conditions are obtained determining whether the transition to <span class="hlt">bubbling</span> is soft or hard; that is, whether the maximum burst amplitude varies continuously or discontinuously with variation of the parameter through its critical value. For soft <span class="hlt">bubbling</span> transitions, the scaling of the maximum burst amplitude with the parameter is derived. For both hard and soft transitions the scaling of the average interburst time with the bifurcation parameter is deduced. Both random (noise) and fixed (mismatch) perturbations are considered. Results of numerical experiments testing our theoretical predictions are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EJPh...29.1263D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EJPh...29.1263D"><span>The Minnaert <span class="hlt">bubble</span>: an acoustic approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Devaud, Martin; Hocquet, Thierry; Bacri, Jean-Claude; Leroy, Valentin</p> <p>2008-11-01</p> <p>We propose an ab initio introduction to the well-known Minnaert pulsating <span class="hlt">bubble</span> at graduate level. After a brief recall of the standard stuff, we begin with a detailed discussion of the radial movements of an air <span class="hlt">bubble</span> in water. This discussion is managed from an acoustic point of view, and using the Lagrangian rather than the Eulerian variables. In unbounded water, the air-water system has a continuum of eigenmodes, some of them correspond to regular Fabry-Pérot resonances. A singular resonance, the lowest one, is shown to coincide with that of Minnaert. In bounded water, the eigenmodes spectrum is discrete, with a finite fundamental frequency. A spectacular quasi-locking of the latter occurs if it happens to exceed the Minnaert frequency, which provides an unforeseen one-<span class="hlt">bubble</span> alternative version of the famous 'hot chocolate effect'. In the (low) frequency domain in which sound propagation inside the <span class="hlt">bubble</span> reduces to a simple 'breathing' (i.e. inflation/deflation), the light air <span class="hlt">bubble</span> can be 'dressed' by the outer water pressure forces, and is turned into the heavy Minnaert <span class="hlt">bubble</span>. Thanks to this unexpected renormalization process, we demonstrate that the Minnaert <span class="hlt">bubble</span> definitely behaves like a true harmonic oscillator of the spring-bob type, but with a damping term and a forcing term in apparent disagreement with those commonly admitted in the literature. Finally, we underline the double role played by the water. In order to tell the water motion associated with water compressibility (i.e. the sound) from the simple incompressible accompaniment of the <span class="hlt">bubble</span> breathing, we introduce a new picture analogous to the electromagnetic radiative picture in Coulomb gauge, which naturally leads us to split the water displacement in an instantaneous and a retarded part. The Minnaert renormalized mass of the dressed <span class="hlt">bubble</span> is then automatically recovered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhFl...19g2106T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhFl...19g2106T"><span>Nonlinear oscillations and collapse of elongated <span class="hlt">bubbles</span> subject to weak viscous effects: Effect of internal overpressure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsiglifis, Kostas; Pelekasis, Nikos A.</p> <p>2007-07-01</p> <p>The details of nonlinear oscillations and collapse of elongated <span class="hlt">bubbles</span>, subject to large internal overpressure, are studied by a boundary integral method. Weak viscous effects on the liquid side are accounted for by integrating the equations of motion across the boundary layer that is formed adjacent to the interface. For relatively large <span class="hlt">bubbles</span> with initial radius R0 on the order of millimeters, PSt=PSt'/(2σ/R0)˜300 and Oh =μ/(σR0ρ)1/2˜200, and an almost spherical initial shape, S˜1, Rayleigh-Taylor instability prevails and the <span class="hlt">bubble</span> breaks up as a result of growth of higher modes and the development of regions of very small radius of curvature; σ, ρ, μ, and PSt' denote the surface tension, density, viscosity, and dimensional static pressure in the host liquid while S is the ratio between the length of the minor semiaxis of the <span class="hlt">bubble</span>, taken as an axisymmetric ellipsoid, and its equivalent radius R0. For finite initial elongations, 0.5⩽S <1, the <span class="hlt">bubble</span> collapses either via two jets that counterpropagate along the axis of symmetry and eventually coalesce at the equatorial plane, or in the form of a sink flow approaching the center of the <span class="hlt">bubble</span> along the equatorial plane. This pattern persists for the above range of initial elongations examined and large internal overpressure amplitudes, ɛB⩾1, irrespective of Oh. It is largely due to the phase in the growth of the second Legendre mode during the after-bounce of the oscillating <span class="hlt">bubble</span>, during which it acquires large enough positive accelerations for collapse to take place. For smaller <span class="hlt">bubbles</span> with initial radius on the order of micrometers, PSt˜4 and Oh ˜20, and small initial elongations, 0.75<S⩽1, viscosity counteracts P2 growth and subsequent jet motion, thus giving <span class="hlt">rise</span> to a critical value of Oh-1 below which the <span class="hlt">bubble</span> eventually returns to its equilibrium spherical shape, whereas above it collapse via jet impact or sink flow is obtained. For moderate elongations, 0.5⩽S⩽0.75, and large</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.D7009M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.D7009M"><span>Gas <span class="hlt">Bubble</span> Dynamics under Mechanical Vibrations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohagheghian, Shahrouz; Elbing, Brian</p> <p>2017-11-01</p> <p>The scientific community has a limited understanding of the <span class="hlt">bubble</span> dynamics under mechanical oscillations due to over simplification of Navier-Stockes equation by neglecting the shear stress tensor and not accounting for body forces when calculating the acoustic radiation force. The current work experimental investigates <span class="hlt">bubble</span> dynamics under mechanical vibration and resulting acoustic field by measuring the <span class="hlt">bubble</span> size and velocity using high-speed imaging. The experimental setup consists of a custom-designed shaker table, cast acrylic <span class="hlt">bubble</span> column, compressed air injection manifold and an optical imaging system. The mechanical vibrations resulted in accelerations between 0.25 to 10 times gravitational acceleration corresponding to frequency and amplitude range of 8 - 22Hz and 1 - 10mm respectively. Throughout testing the void fraction was limited to <5%. The <span class="hlt">bubble</span> size is larger than resonance size and smaller than acoustic wavelength. The amplitude of acoustic pressure wave was estimated using the definition of Bjerknes force in combination with Rayleigh-Plesset equation. Physical behavior of the system was capture and classified. <span class="hlt">Bubble</span> size, velocity as well as size and spatial distribution will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004PhyA..337..565A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004PhyA..337..565A"><span>Fearless versus fearful speculative financial <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andersen, J. V.; Sornette, D.</p> <p>2004-06-01</p> <p>Using a recently introduced rational expectation model of <span class="hlt">bubbles</span>, based on the interplay between stochasticity and positive feedbacks of prices on returns and volatility, we develop a new methodology to test how this model classifies nine time series that have been previously considered as <span class="hlt">bubbles</span> ending in crashes. The model predicts the existence of two anomalous behaviors occurring simultaneously: (i) super-exponential price growth and (ii) volatility growth, that we refer to as the “fearful singular bubble” regime. Out of the nine time series, we find that five pass our tests and can be characterized as “fearful singular bubbles”. The four other cases are the information technology Nasdaq <span class="hlt">bubble</span> and three <span class="hlt">bubbles</span> of the Hang Seng index ending in crashes in 1987, 1994 and 1997. According to our analysis, these four <span class="hlt">bubbles</span> have developed with essentially no significant increase of their volatility. This paper thus proposes that speculative <span class="hlt">bubbles</span> ending in crashes form two groups hitherto unrecognized, namely those accompanied by increasing volatility (reflecting increasing risk perception) and those without change of volatility (reflecting an absence of risk perception).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010APS..DFD.LR009K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010APS..DFD.LR009K"><span>Simulations of <span class="hlt">Bubble</span> Motion in an Oscillating Liquid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kraynik, A. M.; Romero, L. A.; Torczynski, J. R.</p> <p>2010-11-01</p> <p>Finite-element simulations are used to investigate the motion of a gas <span class="hlt">bubble</span> in a liquid undergoing vertical vibration. The effect of <span class="hlt">bubble</span> compressibility is studied by comparing "compressible" <span class="hlt">bubbles</span> that obey the ideal gas law with "incompressible" <span class="hlt">bubbles</span> that are taken to have constant volume. Compressible <span class="hlt">bubbles</span> exhibit a net downward motion away from the free surface that does not exist for incompressible <span class="hlt">bubbles</span>. Net (rectified) velocities are extracted from the simulations and compared with theoretical predictions. The dependence of the rectified velocity on ambient gas pressure, <span class="hlt">bubble</span> diameter, and <span class="hlt">bubble</span> depth are in agreement with the theory. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950011773','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950011773"><span>Time-evolving <span class="hlt">bubbles</span> in two-dimensional stokes flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tanveer, Saleh; Vasconcelos, Giovani L.</p> <p>1994-01-01</p> <p>A general class of exact solutions is presented for a time evolving <span class="hlt">bubble</span> in a two-dimensional slow viscous flow in the presence of surface tension. These solutions can describe a <span class="hlt">bubble</span> in a linear shear flow as well as an expanding or contracting <span class="hlt">bubble</span> in an otherwise quiescent flow. In the case of expanding <span class="hlt">bubbles</span>, the solutions have a simple behavior in the sense that for essentially arbitrary initial shapes the <span class="hlt">bubble</span> will asymptote an expanding circle. Contracting <span class="hlt">bubbles</span>, on the other hand, can develop narrow structures ('near-cusps') on the interface and may undergo 'break up' before all the <span class="hlt">bubble</span>-fluid is completely removed. The mathematical structure underlying the existence of these exact solutions is also investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HMT....54..353L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HMT....54..353L"><span>Recognition and measurement gas-liquid two-phase flow in a vertical concentric annulus at high pressures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Hao; Sun, Baojiang; Guo, Yanli; Gao, Yonghai; Zhao, Xinxin</p> <p>2018-02-01</p> <p>The air-water flow <span class="hlt">characteristics</span> under pressure in the range of 1-6 MPa in a vertical annulus were evaluated in this report. Time-resolved <span class="hlt">bubble</span> <span class="hlt">rising</span> velocity and void fraction were also measured using an electrical void fraction meter. The results showed that the pressure has remarkable effect on the density, <span class="hlt">bubble</span> size and <span class="hlt">rise</span> velocity of the gas. Four flow patterns (<span class="hlt">bubble</span>, cap-<span class="hlt">bubble</span>, cap-slug, and churn) were also observed instead of Taylor <span class="hlt">bubble</span> at high pressure. Additionally, the transition process from <span class="hlt">bubble</span> to cap-<span class="hlt">bubble</span> was investigated at atmospheric and high pressures, respectively. The results revealed that the flow regime transition criteria for atmospheric pressure do not work at high pressure, hence a new flow regime transition model for annular flow channel geometry was developed to predict the flow regime transition, which thereafter exhibited high accuracy at high pressure condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4549848','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4549848"><span>The speed of sound in a gas–vapour <span class="hlt">bubbly</span> liquid</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Prosperetti, Andrea</p> <p>2015-01-01</p> <p>In addition to the vapour of the liquid, <span class="hlt">bubbles</span> in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a <span class="hlt">bubbly</span> liquid with these <span class="hlt">characteristics</span>. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model. PMID:26442146</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26442146','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26442146"><span>The speed of sound in a gas-vapour <span class="hlt">bubbly</span> liquid.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prosperetti, Andrea</p> <p>2015-10-06</p> <p>In addition to the vapour of the liquid, <span class="hlt">bubbles</span> in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a <span class="hlt">bubbly</span> liquid with these <span class="hlt">characteristics</span>. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22591516-robust-acoustic-wave-manipulation-bubbly-liquids','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22591516-robust-acoustic-wave-manipulation-bubbly-liquids"><span>Robust acoustic wave manipulation of <span class="hlt">bubbly</span> liquids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Gumerov, N. A., E-mail: gumerov@umiacs.umd.edu; Center for Micro- and Nanoscale Dynamics of Dispersed Systems, Bashkir State University, Ufa 450076; Akhatov, I. S.</p> <p></p> <p>Experiments with water–air <span class="hlt">bubbly</span> liquids when exposed to acoustic fields of frequency ∼100 kHz and intensity below the cavitation threshold demonstrate that <span class="hlt">bubbles</span> ∼30 μm in diameter can be “pushed” away from acoustic sources by acoustic radiation independently from the direction of gravity. This manifests formation and propagation of acoustically induced transparency waves (waves of the <span class="hlt">bubble</span> volume fraction). In fact, this is a collective effect of <span class="hlt">bubbles</span>, which can be described by a mathematical model of <span class="hlt">bubble</span> self-organization in acoustic fields that matches well with our experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000086.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e000086.html"><span>Hubble's Cosmic <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-08</p> <p>This entrancing image shows a few of the tenuous threads that comprise Sh2-308, a faint and wispy shell of gas located 5,200 light-years away in the constellation of Canis Major (The Great Dog). Sh2-308 is a large <span class="hlt">bubble</span>-like structure wrapped around an extremely large, bright type of star known as a Wolf-Rayet Star — this particular star is called EZ Canis Majoris. These type of stars are among the brightest and most massive stars in the Universe, tens of times more massive than our own sun, and they represent the extremes of stellar evolution. Thick winds continually poured off the progenitors of such stars, flooding their surroundings and draining the outer layers of the Wolf-Rayet stars. The fast wind of a Wolf-Rayet star therefore sweeps up the surrounding material to form <span class="hlt">bubbles</span> of gas. EZ Canis Majoris is responsible for creating the <span class="hlt">bubble</span> of Sh2-308 — the star threw off its outer layers to create the strands visible here. The intense and ongoing radiation from the star pushes the <span class="hlt">bubble</span> out farther and farther, blowing it bigger and bigger. Currently the edges of Sh2-308 are some 60 light-years apart! Beautiful as these cosmic <span class="hlt">bubbles</span> are, they are fleeting. The same stars that form them will also cause their death, eclipsing and subsuming them in violent supernova explosions. Credit: ESA/Hubble & NASA NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA10111&hterms=Blue+star+years&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBlue%2Bstar%2B5%2Byears','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA10111&hterms=Blue+star+years&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBlue%2Bstar%2B5%2Byears"><span><span class="hlt">Bubbly</span> Little Star</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2007-01-01</p> <p><p/> In this processed Spitzer Space Telescope image, baby star HH 46/47 can be seen blowing two massive '<span class="hlt">bubbles</span>.' The star is 1,140 light-years away from Earth. <p/> The infant star can be seen as a white spot toward the center of the Spitzer image. The two <span class="hlt">bubbles</span> are shown as hollow elliptical shells of bluish-green material extending from the star. Wisps of green in the image reveal warm molecular hydrogen gas, while the bluish tints are formed by starlight scattered by surrounding dust. <p/> These <span class="hlt">bubbles</span> formed when powerful jets of gas, traveling at 200 to 300 kilometers per second, or about 120 to 190 miles per second, smashed into the cosmic cloud of gas and dust that surrounds HH 46/47. The red specks at the end of each <span class="hlt">bubble</span> show the presence of hot sulfur and iron gas where the star's narrow jets are currently crashing head-on into the cosmic cloud's gas and dust material. <p/> Whenever astronomers observe a star, or snap a stellar portrait, through the lens of any telescope, they know that what they are seeing is slightly blurred. To clear up the blurring in Spitzer images, astronomers at the Jet Propulsion Laboratory developed an image processing technique for Spitzer called Hi-Res deconvolution. <p/> This process reduces blurring and makes the image sharper and cleaner, enabling astronomers to see the emissions around forming stars in greater detail. When scientists applied this image processing technique to the Spitzer image of HH 46/47, they were able to see winds from the star and jets of gas that are carving the celestial <span class="hlt">bubbles</span>. <p/> This infrared image is a three-color composite, with data at 3.6 microns represented in blue, 4.5 and 5.8 microns shown in green, and 24 microns represented as red.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDR36007D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDR36007D"><span>Bernoulli Suction Effect on Soap <span class="hlt">Bubble</span> Blowing?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davidson, John; Ryu, Sangjin</p> <p>2015-11-01</p> <p>As a model system for thin-film <span class="hlt">bubble</span> with two gas-liquid interfaces, we experimentally investigated the pinch-off of soap <span class="hlt">bubble</span> blowing. Using the lab-built <span class="hlt">bubble</span> blower and high-speed videography, we have found that the scaling law exponent of soap <span class="hlt">bubble</span> pinch-off is 2/3, which is similar to that of soap film bridge. Because air flowed through the decreasing neck of soap film tube, we studied possible Bernoulli suction effect on soap <span class="hlt">bubble</span> pinch-off by evaluating the Reynolds number of airflow. Image processing was utilized to calculate approximate volume of growing soap film tube and the volume flow rate of the airflow, and the Reynolds number was estimated to be 800-3200. This result suggests that soap <span class="hlt">bubbling</span> may involve the Bernoulli suction effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5281049-further-experimentation-bubble-generation-during-transformer-overload','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5281049-further-experimentation-bubble-generation-during-transformer-overload"><span>Further experimentation on <span class="hlt">bubble</span> generation during transformer overload</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Oommen, T.V.</p> <p>1992-03-01</p> <p>This report covers additional work done during 1990 and 1991 on gas <span class="hlt">bubble</span> generation under overload conditions. To improve visual <span class="hlt">bubble</span> detection, a single disc coil was used. To further improve detection, a corona device was also used which signaled the onset of corona activity in the early stages of <span class="hlt">bubble</span> formation. A total of fourteen model tests were conducted, half of which used the Inertaire system, and the remaining, a conservator (COPS). Moisture content of paper in the coil varied from 1.0% to 8.0%; gas (nitrogen) content varied from 1.0% to 8.8%. The results confirmed earlier observations that themore » mathematical <span class="hlt">bubble</span> prediction model was not valid for high gas content model with relatively low moisture levels in the coil. An empirical relationship was formulated to accurately predict <span class="hlt">bubble</span> evolution temperatures from known moisture and gas content values. For low moisture content models (below 2%), the simple Piper relationship was sufficient to predict <span class="hlt">bubble</span> evolution temperatures, regardless of gas content. Moisture in the coil appears to be the key factor in <span class="hlt">bubble</span> generation. Gas blanketed (Inertaire) systems do not appear to be prone to premature <span class="hlt">bubble</span> generation from overloads as previously thought. The new <span class="hlt">bubble</span> prediction model reveals that for a coil with 2% moisture, the <span class="hlt">bubble</span> evolution temperature would be about 140{degrees}C. Since old transformers in service may have as much as 2% moisture in paper, the 140{degrees}C <span class="hlt">bubble</span> evolution temperature may be taken as the lower limit of <span class="hlt">bubble</span> evolution temperature under overload conditions for operating transformers. Drier insulation would raise the <span class="hlt">bubble</span> evolution temperature.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24141738','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24141738"><span><span class="hlt">Bubble</span>-driven mixer integrated with a microfluidic bead-based ELISA for rapid bladder cancer biomarker detection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, Yen-Heng; Wang, Chia-Chu; Lei, Kin Fong</p> <p>2014-04-01</p> <p>In this study, fine <span class="hlt">bubbles</span> were successfully generated and used as a simple, low-cost driving force for mixing fluids in an integrated microfluidic bead-based enzyme-linked immunosorbent assay (ELISA) to rapidly and quantitatively detect apolipoprotein A1 (APOA1), a biomarker highly correlated with bladder cancer. A wooden gas diffuser was embedded underneath a microfluidic chip to refine injected air and generate <span class="hlt">bubbles</span> of less than 0.3 mm. The <span class="hlt">rising</span> <span class="hlt">bubbles</span> caused disturbances and convection in the fluid, increasing the probability of analyte interaction. This setup not only simplifies the micromixer design but also achieves rapid mixing with a small airflow as a force. We used this <span class="hlt">bubble</span>-driven micromixer in a bead-based ELISA that targeted APOA1. The results indicate that this micromixer reduced the time for each incubation from 60 min in the conventional assay to 8 min with the chip, resulting in a reduction of total ELISA reaction time from 3-4 h to 30-40 min. Furthermore, the concentration detection limit was 9.16 ng/mL, which was lower than the detection cut-off value (11.16 ng/mL) for bladder cancer diagnosis reported in the literature. Therefore, this chip can be used to achieve rapid low-cost bladder cancer detection and may be used in point-of-care cancer monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.9302S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.9302S"><span>900-m high gas plumes <span class="hlt">rising</span> from marine sediments containing structure II hydrates at Vestnesa Ridge, offshore W-Svalbard</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, Andrew J.; Mienert, Jürgen; Bünz, Stefan; Greinert, Jens; Rasmussen, Tine L.</p> <p>2013-04-01</p> <p>We study an arctic sediment drift in ~1200 m water depth at Vestnesa Ridge, offshore western Svalbard. The ridge is spotted with pockmarks that range in size from a few meters to hundreds of meters in diameter and centimeters to tens of meters in height (e.g. Vogt et al., 1994). There is a strong negative-polarity seismic reflection below the ridge that is interpreted to record a negative impedance contrast marking the boundary between gas hydrate and water above and free gas and water below: it is the bottom-simulating reflector (BSR). Seismically transparent zones, interpreted as gas chimneys, extend from pockmarks at the seafloor to depths below the BSR (180-220 meters below the seafloor) (Bünz et al., 2012). Gas flares, gas hydrate, and methane-seep-specific biological communities (pogonphora and begiatoa bacterial mats) have been observed adjacent to pockmarks at the ridge (Bünz et al., 2012). We present new single-beam echosounding data that were acquired during 2010 and 2012 cruises on the R/V Helmer Hanssen at Vestnesa Ridge using a Simrad EK60 system that operates at frequencies of 18 and 38 kHz. During both cruises which lasted 3-5 days, we detected continuous <span class="hlt">bubble</span> release from 4 separate pockmarks in 2010 and 6 separate pockmarks in 2012. There were no noticeable, short-term (hourly or daily) variations in the <span class="hlt">bubble</span> release from the pockmarks, indicating that the venting from the pockmarks does not undergo rapid changes. Plumes from the pockmarks <span class="hlt">rise</span> between 875 to 925m above the seafloor to a final water depth of 325 to 275m, respectively. This depth is in excellent agreement with the top of the hydrate stability zone (275 meters below sea level) for the gas composition of hydrate sampled at the ridge (96.31% C1; 3.36% C2; 0.21% C3; 0.11% IC4; 0.01% NC4). This suggests that hydrate skins are forming around the gas <span class="hlt">bubbles</span>, inhibiting the dissolution of gas, and allowing the <span class="hlt">bubbles</span> to <span class="hlt">rise</span> to such great heights in the water column. Our results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA154575','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA154575"><span><span class="hlt">Bubble</span> Dynamics in Polymer Solutions Undergoing Shear.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1985-04-01</p> <p>cavitation <span class="hlt">bubble</span> in water has been established as the fundamental theoretical approach to understanding this phenomenon. LA_ Laser -induced...cavitation inception. 1-2 Polymer effects on cavity appearance. 2-1 Spherical laser -induced <span class="hlt">bubble</span> dynamics. 2-2 Vapor cavity jet formation. 2-3 <span class="hlt">Bubble</span>...distilled water. 2-6B Nonspherical <span class="hlt">bubble</span> dynamics in dilute polymer. 3-1 Closed-loop hydraulic cavitation tunnel. 3-2 Laser system optical components. 3-3</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5018722','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5018722"><span>Observations of internal flow inside an evaporating nanofluid sessile droplet in the presence of an entrapped air <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shin, Dong Hwan; Allen, Jeffrey S.; Lee, Seong Hyuk; Choi, Chang Kyoung</p> <p>2016-01-01</p> <p>Using a unique, near-field microscopy technique, fringe patterns and nanoparticle motions are visualized immediately following a nanofluid droplet deposition on a glass substrate in which an air <span class="hlt">bubble</span> is entrapped. The nanofluid consists of DI-water, 0.10% Aluminum Oxide nanoparticles with an average diameter of 50 nm, and 0.0005% yellow-green polystyrene fluorescent particles of 1 μm diameter. High-speed, fluorescent-mode confocal imaging enables investigation of depth-wise sectioned particle movements in the nanofluid droplet inside which a <span class="hlt">bubble</span> is entrapped. The static contact angle is increased when a <span class="hlt">bubble</span> is applied. In the presence of the <span class="hlt">bubble</span> in the droplet, the observed flow toward the center of the droplet is opposite to the flow observed in a droplet without the <span class="hlt">bubble</span>. When the <span class="hlt">bubble</span> is present, the evaporation process is retarded. Also, random motion is observed in the contact line region instead of the typical evaporation-driven flow toward the droplet edge. Once the <span class="hlt">bubble</span> bursts, however, the total evaporation time decreases due to the change in the contact line <span class="hlt">characteristics</span>. Moreover, the area of fringe patterns beneath the <span class="hlt">bubble</span> increases with time. Discussed herein is a unique internal flow that has not been observed in nanofluid droplet evaporation. PMID:27615999</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27615999','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27615999"><span>Observations of internal flow inside an evaporating nanofluid sessile droplet in the presence of an entrapped air <span class="hlt">bubble</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shin, Dong Hwan; Allen, Jeffrey S; Lee, Seong Hyuk; Choi, Chang Kyoung</p> <p>2016-09-12</p> <p>Using a unique, near-field microscopy technique, fringe patterns and nanoparticle motions are visualized immediately following a nanofluid droplet deposition on a glass substrate in which an air <span class="hlt">bubble</span> is entrapped. The nanofluid consists of DI-water, 0.10% Aluminum Oxide nanoparticles with an average diameter of 50 nm, and 0.0005% yellow-green polystyrene fluorescent particles of 1 μm diameter. High-speed, fluorescent-mode confocal imaging enables investigation of depth-wise sectioned particle movements in the nanofluid droplet inside which a <span class="hlt">bubble</span> is entrapped. The static contact angle is increased when a <span class="hlt">bubble</span> is applied. In the presence of the <span class="hlt">bubble</span> in the droplet, the observed flow toward the center of the droplet is opposite to the flow observed in a droplet without the <span class="hlt">bubble</span>. When the <span class="hlt">bubble</span> is present, the evaporation process is retarded. Also, random motion is observed in the contact line region instead of the typical evaporation-driven flow toward the droplet edge. Once the <span class="hlt">bubble</span> bursts, however, the total evaporation time decreases due to the change in the contact line <span class="hlt">characteristics</span>. Moreover, the area of fringe patterns beneath the <span class="hlt">bubble</span> increases with time. Discussed herein is a unique internal flow that has not been observed in nanofluid droplet evaporation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030025342','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030025342"><span>Time and Space Resolved Heat Transfer Measurements Under Nucleate <span class="hlt">Bubbles</span> with Constant Heat Flux Boundary Conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Myers, Jerry G.; Hussey, Sam W.; Yee, Glenda F.; Kim, Jungho</p> <p>2003-01-01</p> <p>Investigations into single <span class="hlt">bubble</span> pool boiling phenomena are often complicated by the difficulties in obtaining time and space resolved information in the <span class="hlt">bubble</span> region. This usually occurs because the heaters and diagnostics used to measure heat transfer data are often on the order of, or larger than, the <span class="hlt">bubble</span> <span class="hlt">characteristic</span> length or region of influence. This has contributed to the development of many different and sometimes contradictory models of pool boiling phenomena and dominant heat transfer mechanisms. Recent investigations by Yaddanapyddi and Kim and Demiray and Kim have obtained time and space resolved heat transfer information at the <span class="hlt">bubble</span>/heater interface under constant temperature conditions using a novel micro-heater array (10x10 array, each heater 100 microns on a side) that is semi-transparent and doubles as a measurement sensor. By using active feedback to maintain a state of constant temperature at the heater surface, they showed that the area of influence of <span class="hlt">bubbles</span> generated in FC-72 was much smaller than predicted by standard models and that micro-conduction/micro-convection due to re-wetting dominated heat transfer effects. This study seeks to expand on the previous work by making time and space resolved measurements under <span class="hlt">bubbles</span> nucleating on a micro-heater array operated under constant heat flux conditions. In the planned investigation, wall temperature measurements made under a single <span class="hlt">bubble</span> nucleation site will be synchronized with high-speed video to allow analysis of the <span class="hlt">bubble</span> energy removal from the wall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=nucleation&id=EJ980893','ERIC'); return false;" href="https://eric.ed.gov/?q=nucleation&id=EJ980893"><span>Evaporation, Boiling and <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Goodwin, Alan</p> <p>2012-01-01</p> <p>Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of <span class="hlt">bubbles</span> of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention <span class="hlt">bubble</span> formation in this context. The…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22308840-bubble-detection-system-propellant-filling-pipeline','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22308840-bubble-detection-system-propellant-filling-pipeline"><span>A <span class="hlt">bubble</span> detection system for propellant filling pipeline</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wen, Wen; Zong, Guanghua; Bi, Shusheng</p> <p>2014-06-15</p> <p>This paper proposes a <span class="hlt">bubble</span> detection system based on the ultrasound transmission method, mainly for probing high-speed <span class="hlt">bubbles</span> in the satellite propellant filling pipeline. First, three common ultrasonic detection methods are compared and the ultrasound transmission method is used in this paper. Then, the ultrasound beam in a vertical pipe is investigated, suggesting that the width of the beam used for detection is usually smaller than the internal diameter of the pipe, which means that when <span class="hlt">bubbles</span> move close to the pipe wall, they may escape from being detected. A special device is designed to solve this problem. It canmore » generate the spiral flow to force all the <span class="hlt">bubbles</span> to ascend along the central line of the pipe. In the end, experiments are implemented to evaluate the performance of this system. <span class="hlt">Bubbles</span> of five different sizes are generated and detected. Experiment results show that the sizes and quantity of <span class="hlt">bubbles</span> can be estimated by this system. Also, the <span class="hlt">bubbles</span> of different radii can be distinguished from each other. The numerical relationship between the ultrasound attenuation and the <span class="hlt">bubble</span> radius is acquired and it can be utilized for estimating the unknown <span class="hlt">bubble</span> size and measuring the total <span class="hlt">bubble</span> volume.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26133052','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26133052"><span>Dynamics of Single Hydrogen <span class="hlt">Bubbles</span> at a Platinum Microelectrode.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Xuegeng; Karnbach, Franziska; Uhlemann, Margitta; Odenbach, Stefan; Eckert, Kerstin</p> <p>2015-07-28</p> <p><span class="hlt">Bubble</span> dynamics, including the formation, growth, and detachment, of single H2 <span class="hlt">bubbles</span> was studied at a platinum microelectrode during the electrolysis of 1 M H2SO4 electrolyte. The <span class="hlt">bubbles</span> were visualized through a microscope by a high-speed camera. Electrochemical measurements were conducted in parallel to measure the transient current. The periodic current oscillations, resulting from the periodic formation and detachment of single <span class="hlt">bubbles</span>, allow the <span class="hlt">bubble</span> lifetime and size to be predicted from the transient current. A comparison of the <span class="hlt">bubble</span> volume calculated from the current and from the recorded <span class="hlt">bubble</span> image shows a gas evolution efficiency increasing continuously with the growth of the <span class="hlt">bubble</span> until it reaches 100%. Two different substrates, glass and epoxy, were used to embed the Pt wire. While nearly no difference was found with respect to the growth law for the <span class="hlt">bubble</span> radius, the contact angle differs strongly for the two types of cell. Data provided for the contact point evolution further complete the image of single hydrogen <span class="hlt">bubble</span> growth. Finally, the velocity field driven by the detached <span class="hlt">bubble</span> was measured by means of PIV, and the effects of the convection on the subsequent <span class="hlt">bubble</span> were evaluated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2480679','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2480679"><span><span class="hlt">Bubbles</span>, Gating, and Anesthetics in Ion Channels</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Roth, Roland; Gillespie, Dirk; Nonner, Wolfgang; Eisenberg, Robert E.</p> <p>2008-01-01</p> <p>We suggest that <span class="hlt">bubbles</span> are the bistable hydrophobic gates responsible for the on-off transitions of single channel currents. In this view, many types of channels gate by the same physical mechanism—dewetting by capillary evaporation—but different types of channels use different sensors to modulate hydrophobic properties of the channel wall and thereby trigger and control <span class="hlt">bubbles</span> and gating. Spontaneous emptying of channels has been seen in many simulations. Because of the physics involved, such phase transitions are inherently sensitive, unstable threshold phenomena that are difficult to simulate reproducibly and thus convincingly. We present a thermodynamic analysis of a <span class="hlt">bubble</span> gate using morphometric density functional theory of classical (not quantum) mechanics. Thermodynamic analysis of phase transitions is generally more reproducible and less sensitive to details than simulations. Anesthetic actions of inert gases—and their interactions with hydrostatic pressure (e.g., nitrogen narcosis)—can be easily understood by actions on <span class="hlt">bubbles</span>. A general theory of gas anesthesia may involve <span class="hlt">bubbles</span> in channels. Only experiments can show whether, or when, or which channels actually use <span class="hlt">bubbles</span> as hydrophobic gates: direct observation of <span class="hlt">bubbles</span> in channels is needed. Existing experiments show thin gas layers on hydrophobic surfaces in water and suggest that <span class="hlt">bubbles</span> nearly exist in bulk water. PMID:18234836</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026855','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026855"><span>Gravity Wave Seeding of Equatorial Plasma <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Singh, Sardul; Johnson, F. S.; Power, R. A.</p> <p>1997-01-01</p> <p>Some examples from the Atmosphere Explorer E data showing plasma <span class="hlt">bubble</span> development from wavy ion density structures in the bottomside F layer are described. The wavy structures mostly had east-west wavelengths of 150-800 km, in one example it was about 3000 km. The ionization troughs in the wavy structures later broke up into either a multiple-<span class="hlt">bubble</span> patch or a single <span class="hlt">bubble</span>, depending upon whether, in the precursor wavy structure, shorter wavelengths were superimposed on the larger scale wavelengths. In the multiple <span class="hlt">bubble</span> patches, intrabubble spacings vaned from 55 km to 140 km. In a fully developed equatorial spread F case, east-west wavelengths from 690 km down to about 0.5 km were present simultaneously. The spacings between <span class="hlt">bubble</span> patches or between <span class="hlt">bubbles</span> in a patch appear to be determined by the wavelengths present in the precursor wave structure. In some cases, deeper <span class="hlt">bubbles</span> developed on the western edge of a <span class="hlt">bubble</span> patch, suggesting an east-west asymmetry. Simultaneous horizontal neutral wind measurements showed wavelike perturbations that were closely associated with perturbations in the plasma horizontal drift velocity. We argue that the wave structures observed here that served as the initial seed ion density perturbations were caused by gravity waves, strengthening the view that gravity waves seed equatorial spread F irregularities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920056524&hterms=cartilage&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcartilage','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920056524&hterms=cartilage&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcartilage"><span>Cartilage formation in the CELLS 'double <span class="hlt">bubble</span>' hardware</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Duke, P. J.; Arizpe, Jorge; Montufar-Solis, Dina</p> <p>1991-01-01</p> <p>The CELLS experiment scheduled to be flown on the first International Microgravity Laboratory is designed to study the effect of microgravity on the cartilage formation, by measuring parameters of growth in a differentiating cartilage cell culture. This paper investigates the conditions for this experiment by studying cartilage differentiation in the '<span class="hlt">bubble</span> exchange' hardware with the 'double <span class="hlt">bubble</span>' design in which the <span class="hlt">bubbles</span> are joined by a flange which also overlays the gasket. Four types of double <span class="hlt">bubbles</span> (or double gas permeable membranes) were tested: injection-molded <span class="hlt">bubbles</span> 0.01- and 0.005-in. thick, and compression molded <span class="hlt">bubbles</span> 0.015- and 0.01-in. thick. It was found that double <span class="hlt">bubble</span> membranes of 0.005- and 0.010-in. thickness supported cartilage differentiation, while the 0.015-in. <span class="hlt">bubbles</span> did not. It was also found that nodule count, used in this study as a parameter, is not the best measure of the amount of cartilage differentiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..MAR.H1311H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..MAR.H1311H"><span>Microstreaming from Sessile Semicylindrical <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hilgenfeldt, Sascha; Rallabandi, Bhargav; Guo, Lin; Wang, Cheng</p> <p>2014-03-01</p> <p>Powerful steady streaming flows result from the ultrasonic driving of microbubbles, in particular when these <span class="hlt">bubbles</span> have semicylindrical cross section and are positioned in contact with a microfluidic channel wall. We have used this streaming in experiment to develop novel methods for trapping and sorting of microparticles by size, as well as for micromixing. Theoretically, we arrive at an analytical description of the streaming flow field through an asymptotic computation that, for the first time, reconciles the boundary layers around the <span class="hlt">bubble</span> and along the substrate wall, and also takes into account the oscillation modes of the <span class="hlt">bubble</span>. This approach gives insight into changes in the streaming pattern with <span class="hlt">bubble</span> size and driving frequency, including a reversal of the flow direction at high frequencies with potentially useful applications. Present address: Mechanical and Aerospace Engineering, Missouri S &T.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018E3SWC..3302006V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018E3SWC..3302006V"><span>Investigation the effect of outdoor air infiltration on the heat-shielding <span class="hlt">characteristics</span> the outer walls of high-<span class="hlt">rise</span> buildings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vytchikov, Yu. S.; Kostuganov, A. B.; Saparev, M. E.; Belyakov, I. G.</p> <p>2018-03-01</p> <p>The presented article considers the influence of infiltrated outdoor air on the heat-shielding <span class="hlt">characteristics</span> of the exterior walls of modern residential and public buildings. A review of the sources devoted to this problem confirmed its relevance at the present time, especially for high-<span class="hlt">rise</span> buildings. The authors of the article analyzed the effect of longitudinal and transverse air infiltration on the heat-shielding <span class="hlt">characteristics</span> of the outer wall of a 25-story building that was built in Samara. The results showed a significant reduction of the reduced resistance to the heat transfer of the outer wall when air is infiltrated through it. There are the results of full-scale examination of external walls to confirm the calculated data. Based on the results of the study carried out by the authors of the article, general recommendations on the internal finishing of the outer walls of high-<span class="hlt">rise</span> buildings are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/175495','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/175495"><span>Numerical simulation of high Reynolds number <span class="hlt">bubble</span> motion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>McLaughlin, J.B.</p> <p></p> <p>This paper presents the results of numerical simulations of <span class="hlt">bubble</span> motion. All the results are for single <span class="hlt">bubbles</span> in unbounded fluids. The liquid phase is quiescent except for the motion created by the <span class="hlt">bubble</span>, which is axisymmetric. The main focus of the paper is on <span class="hlt">bubbles</span> that are of order 1 mm in diameter in water. Of particular interest is the effect of surfactant molecules on <span class="hlt">bubble</span> motion. Results for the {open_quotes}insoluble surfactant{close_quotes} model will be presented. These results extend research by other investigators to finite Reynolds numbers. The results indicate that, by assuming complete coverage of the <span class="hlt">bubble</span> surface,more » one obtains good agreement with experimental observations of <span class="hlt">bubble</span> motion in tap water. The effect of surfactant concentration on the separation angle is discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApPhL.111x1604Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApPhL.111x1604Z"><span>Formation of soap <span class="hlt">bubbles</span> by gas jet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Maolei; Li, Min; Chen, Zhiyuan; Han, Jifeng; Liu, Dong</p> <p>2017-12-01</p> <p>Soap <span class="hlt">bubbles</span> can be easily generated by various methods, while their formation process is complicated and still worth studying. A model about the <span class="hlt">bubble</span> formation process was proposed in the study by Salkin et al. [Phys. Rev. Lett. 116, 077801 (2016)] recently, and it was reported that the <span class="hlt">bubbles</span> were formed when the gas blowing velocity was above one threshold. However, after a detailed study of these experiments, we found that the <span class="hlt">bubbles</span> could be generated in two velocity ranges which corresponded to the laminar and turbulent gas jet, respectively, and the predicted threshold was only effective for turbulent gas flow. The study revealed that the <span class="hlt">bubble</span> formation was greatly influenced by the aerodynamics of the gas jet blowing to the film, and these results will help to further understand the formation mechanism of the soap <span class="hlt">bubble</span> as well as the interaction between the gas jet and the thin liquid film.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22140098-magnetic-topology-bubbles-quiescent-prominences','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22140098-magnetic-topology-bubbles-quiescent-prominences"><span>MAGNETIC TOPOLOGY OF <span class="hlt">BUBBLES</span> IN QUIESCENT PROMINENCES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Dudik, J.; Aulanier, G.; Schmieder, B.</p> <p></p> <p>We study a polar-crown prominence with a <span class="hlt">bubble</span> and its plume observed in several coronal filters by the SDO/AIA and in H{alpha} by the MSDP spectrograph in Bialkow (Poland) to address the following questions: what is the brightness of prominence <span class="hlt">bubbles</span> in EUV with respect to the corona outside of the prominence and the prominence coronal cavity? What is the geometry and topology of the magnetic field in the <span class="hlt">bubble</span>? What is the nature of the vertical threads seen within prominences? We find that the brightness of the <span class="hlt">bubble</span> and plume is lower than the brightness of the corona outsidemore » of the prominence, and is similar to that of the coronal cavity. We constructed linear force-free models of prominences with <span class="hlt">bubbles</span>, where the flux rope is perturbed by inclusion of parasitic bipoles. The arcade field lines of the bipole create the <span class="hlt">bubble</span>, which is thus devoid of magnetic dips. Shearing the bipole or adding a second one can lead to cusp-shaped prominences with <span class="hlt">bubbles</span> similar to the observed ones. The <span class="hlt">bubbles</span> have complex magnetic topology, with a pair of coronal magnetic null points linked by a separator outlining the boundary between the <span class="hlt">bubble</span> and the prominence body. We conjecture that plume formation involves magnetic reconnection at the separator. Depending on the viewing angle, the prominence can appear either anvil-shaped with predominantly horizontal structures, or cusp-shaped with predominantly vertical structuring. The latter is an artifact of the alignment of magnetic dips with respect to the prominence axis and the line of sight.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2583453','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2583453"><span>Interaction of lithotripter shockwaves with single inertial cavitation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Klaseboer, Evert; Fong, Siew Wan; Turangan, Cary K.; Khoo, Boo Cheong; Szeri, Andrew J.; Calvisi, Michael L.; Sankin, Georgy N.; Zhong, Pei</p> <p>2008-01-01</p> <p>The dynamic interaction of a shockwave (modelled as a pressure pulse) with an initially spherically oscillating <span class="hlt">bubble</span> is investigated. Upon the shockwave impact, the <span class="hlt">bubble</span> deforms non-spherically and the flow field surrounding the <span class="hlt">bubble</span> is determined with potential flow theory using the boundary-element method (BEM). The primary advantage of this method is its computational efficiency. The simulation process is repeated until the two opposite sides of the <span class="hlt">bubble</span> surface collide with each other (i.e. the formation of a jet along the shockwave propagation direction). The collapse time of the <span class="hlt">bubble</span>, its shape and the velocity of the jet are calculated. Moreover, the impact pressure is estimated based on water-hammer pressure theory. The Kelvin impulse, kinetic energy and <span class="hlt">bubble</span> displacement (all at the moment of jet impact) are also determined. Overall, the simulated results compare favourably with experimental observations of lithotripter shockwave interaction with single <span class="hlt">bubbles</span> (using laser-induced <span class="hlt">bubbles</span> at various oscillation stages). The simulations confirm the experimental observation that the most intense collapse, with the highest jet velocity and impact pressure, occurs for <span class="hlt">bubbles</span> with intermediate size during the contraction phase when the collapse time of the <span class="hlt">bubble</span> is approximately equal to the compressive pulse duration of the shock wave. Under this condition, the maximum amount of energy of the incident shockwave is transferred to the collapsing <span class="hlt">bubble</span>. Further, the effect of the <span class="hlt">bubble</span> contents (ideal gas with different initial pressures) and the initial conditions of the <span class="hlt">bubble</span> (initially oscillating vs. non-oscillating) on the dynamics of the shockwave–<span class="hlt">bubble</span> interaction are discussed. PMID:19018296</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19018296','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19018296"><span>Interaction of lithotripter shockwaves with single inertial cavitation <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klaseboer, Evert; Fong, Siew Wan; Turangan, Cary K; Khoo, Boo Cheong; Szeri, Andrew J; Calvisi, Michael L; Sankin, Georgy N; Zhong, Pei</p> <p>2007-01-01</p> <p>The dynamic interaction of a shockwave (modelled as a pressure pulse) with an initially spherically oscillating <span class="hlt">bubble</span> is investigated. Upon the shockwave impact, the <span class="hlt">bubble</span> deforms non-spherically and the flow field surrounding the <span class="hlt">bubble</span> is determined with potential flow theory using the boundary-element method (BEM). The primary advantage of this method is its computational efficiency. The simulation process is repeated until the two opposite sides of the <span class="hlt">bubble</span> surface collide with each other (i.e. the formation of a jet along the shockwave propagation direction). The collapse time of the <span class="hlt">bubble</span>, its shape and the velocity of the jet are calculated. Moreover, the impact pressure is estimated based on water-hammer pressure theory. The Kelvin impulse, kinetic energy and <span class="hlt">bubble</span> displacement (all at the moment of jet impact) are also determined. Overall, the simulated results compare favourably with experimental observations of lithotripter shockwave interaction with single <span class="hlt">bubbles</span> (using laser-induced <span class="hlt">bubbles</span> at various oscillation stages). The simulations confirm the experimental observation that the most intense collapse, with the highest jet velocity and impact pressure, occurs for <span class="hlt">bubbles</span> with intermediate size during the contraction phase when the collapse time of the <span class="hlt">bubble</span> is approximately equal to the compressive pulse duration of the shock wave. Under this condition, the maximum amount of energy of the incident shockwave is transferred to the collapsing <span class="hlt">bubble</span>. Further, the effect of the <span class="hlt">bubble</span> contents (ideal gas with different initial pressures) and the initial conditions of the <span class="hlt">bubble</span> (initially oscillating vs. non-oscillating) on the dynamics of the shockwave-<span class="hlt">bubble</span> interaction are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EPJD...60..661G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EPJD...60..661G"><span>Time-resolved processes in a pulsed electrical discharge in argon <span class="hlt">bubbles</span> in water</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gershman, S.; Belkind, A.</p> <p>2010-12-01</p> <p>A phenomenological picture of a pulsed electrical discharge in gas <span class="hlt">bubbles</span> in water is produced by combining electrical, spectroscopic, and imaging characterization methods. The discharge is generated by applying 1 μ s pulses of 5 to 20 kV between a needle and a disk electrode submerged in water. An Ar gas <span class="hlt">bubble</span> surrounds the tip of the needle electrode. Imaging, electrical <span class="hlt">characteristics</span>, and time-resolved optical emission spectroscopic data suggest a fast streamer propagation mechanism and the formation of a plasma channel in the <span class="hlt">bubble</span>. Comparing the electrical and imaging data for consecutive pulses applied to the <span class="hlt">bubble</span> at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from the presence of long-lived chemical species, such as ozone and oxygen. Imaging and electrical data show the presence of two discharge events during each applied voltage pulse, a forward discharge near the beginning of the applied pulse depositing charge on the surface of the <span class="hlt">bubble</span> and a reverse discharge removing the accumulated charge from the water/gas interface when the applied voltage is turned off. The pd value of ~ 300-500 torr cm, the 1 μs long pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique compared to the traditional corona or dielectric barrier discharges.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720004579','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720004579"><span>Analysis of cavitation <span class="hlt">bubble</span> dynamics in a liquid</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fontenot, L. L.; Lee, Y. C.</p> <p>1971-01-01</p> <p>General differential equations governing the dynamics of the cavitation <span class="hlt">bubbles</span> in a liquid were derived. With the assumption of spherical symmetry the governing equations were simplified. Closed form solutions were obtained for simple cases, and numerical solutions were calculated for complicated ones. The growth and the collapse of the <span class="hlt">bubble</span> were analyzed, oscillations of the <span class="hlt">bubbles</span> were studied, and the stability of the cavitation <span class="hlt">bubbles</span> were investigated. The results show that the cavitation <span class="hlt">bubbles</span> are unstable, and the oscillation is not sinusoidal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26382410','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26382410"><span>Simple improvements to classical <span class="hlt">bubble</span> nucleation models.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tanaka, Kyoko K; Tanaka, Hidekazu; Angélil, Raymond; Diemand, Jürg</p> <p>2015-08-01</p> <p>We revisit classical nucleation theory (CNT) for the homogeneous <span class="hlt">bubble</span> nucleation rate and improve the classical formula using a correct prefactor in the nucleation rate. Most of the previous theoretical studies have used the constant prefactor determined by the <span class="hlt">bubble</span> growth due to the evaporation process from the <span class="hlt">bubble</span> surface. However, the growth of <span class="hlt">bubbles</span> is also regulated by the thermal conduction, the viscosity, and the inertia of liquid motion. These effects can decrease the prefactor significantly, especially when the liquid pressure is much smaller than the equilibrium one. The deviation in the nucleation rate between the improved formula and the CNT can be as large as several orders of magnitude. Our improved, accurate prefactor and recent advances in molecular dynamics simulations and laboratory experiments for argon <span class="hlt">bubble</span> nucleation enable us to precisely constrain the free energy barrier for <span class="hlt">bubble</span> nucleation. Assuming the correction to the CNT free energy is of the functional form suggested by Tolman, the precise evaluations of the free energy barriers suggest the Tolman length is ≃0.3σ independently of the temperature for argon <span class="hlt">bubble</span> nucleation, where σ is the unit length of the Lennard-Jones potential. With this Tolman correction and our prefactor one gets accurate <span class="hlt">bubble</span> nucleation rate predictions in the parameter range probed by current experiments and molecular dynamics simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EPJWC.18002038J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EPJWC.18002038J"><span>Comparison of cavitation <span class="hlt">bubbles</span> evolution in viscous media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jasikova, Darina; Schovanec, Petr; Kotek, Michal; Kopecky, Vaclav</p> <p>2018-06-01</p> <p>There have been tried many types of liquids with different ranges of viscosity values that have been tested to form a single cavitation <span class="hlt">bubble</span>. The purpose of these experiments was to observe the behaviour of cavitation <span class="hlt">bubbles</span> in media with different ranges of absorbance. The most of the method was based on spark to induced superheat limit of liquid. Here we used arrangement of the laser-induced breakdown (LIB) method. There were described the set cavitation setting that affects the size <span class="hlt">bubble</span> in media with different absorbance. We visualized the cavitation <span class="hlt">bubble</span> with a 60 kHz high speed camera. We used here shadowgraphy setup for the <span class="hlt">bubble</span> visualization. There were observed time development and <span class="hlt">bubble</span> extinction in various media, where the size of the <span class="hlt">bubble</span> in the silicone oil was extremely small, due to the absorbance size of silicon oil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhyA..492...50W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhyA..492...50W"><span>A note on effects of rational <span class="hlt">bubble</span> on portfolios</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Chan; Nie, Pu-yan</p> <p>2018-02-01</p> <p>In general, demand increases in wealth and decreases in price in microeconomics. We thereby propose a completely different perspective. By establishing expected utility function of investors, this article introduces one rational <span class="hlt">bubble</span> asset and one <span class="hlt">bubble</span> free asset in portfolios and focuses on the effects of <span class="hlt">bubble</span> on investment portfolios from wealth and price perspectives. All conclusions are obtained by theoretical analysis with microeconomics theory. We argue that inferior goods and Giffen behavior can occur for the <span class="hlt">bubble</span> free asset in microeconomic fields. The results can help investors to recognize <span class="hlt">bubble</span> assets and <span class="hlt">bubble</span> free assets more scientifically. Both <span class="hlt">bubble</span> and <span class="hlt">bubble</span> free assets can be inferior goods under some conditions, so we cannot to say which asset better than the other one absolutely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvE..83e1609L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvE..83e1609L"><span><span class="hlt">Bubble</span> nucleation in stout beers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, W. T.; McKechnie, J. S.; Devereux, M. G.</p> <p>2011-05-01</p> <p><span class="hlt">Bubble</span> nucleation in weakly supersaturated solutions of carbon dioxide—such as champagne, sparkling wines, and carbonated beers—is well understood. <span class="hlt">Bubbles</span> grow and detach from nucleation sites: gas pockets trapped within hollow cellulose fibers. This mechanism appears not to be active in stout beers that are supersaturated solutions of nitrogen and carbon dioxide. In their canned forms these beers require additional technology (widgets) to release the <span class="hlt">bubbles</span> which will form the head of the beer. We extend the mathematical model of <span class="hlt">bubble</span> nucleation in carbonated liquids to the case of two gases and show that this nucleation mechanism is active in stout beers, though substantially slower than in carbonated beers and confirm this by observation. A rough calculation suggests that despite the slowness of the process, applying a coating of hollow porous fibers to the inside of a can or bottle could be a potential replacement for widgets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110020424','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110020424"><span>Using an Ultrasonic Instrument to Size Extravascular <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Magari, Patrick J.; Kline-Schroder, J.; Kenton, Marc A.</p> <p>2004-01-01</p> <p>In an ongoing development project, microscopic <span class="hlt">bubbles</span> in extravascular tissue in a human body will be detected by use of an enhanced version of the apparatus described in Ultrasonic <span class="hlt">Bubble</span>- Sizing Instrument (MSC-22980), NASA Tech Briefs, Vol. 24, No. 10 (October 2000), page 62. To recapitulate: The physical basis of the instrument is the use of ultrasound to excite and measure the resonant behavior (oscillatory expansion and contraction) of <span class="hlt">bubbles</span>. The resonant behavior is a function of the <span class="hlt">bubble</span> diameter; the instrument exploits the diameter dependence of the resonance frequency and the general nonlinearity of the ultrasonic response of <span class="hlt">bubbles</span> to detect <span class="hlt">bubbles</span> and potentially measure their diameters. In the cited prior article, the application given most prominent mention was the measurement of gaseous emboli (essentially, gas <span class="hlt">bubbles</span> in blood vessels) that cause decompression sickness and complications associated with cardiopulmonary surgery. According to the present proposal, the instrument capabilities would be extended to measure extravascular <span class="hlt">bubbles</span> with diameters in the approximate range of 1 to 30 m. The proposed use of the instrument could contribute further to the understanding and prevention of decompression sickness: There is evidence that suggests that prebreathing oxygen greatly reduces the risk of decompression sickness by reducing the number of microscopic extravascular <span class="hlt">bubbles</span>. By using the ultrasonic <span class="hlt">bubble</span>-sizing instrument to detect and/or measure the sizes of such <span class="hlt">bubbles</span>, it might be possible to predict the risk of decompression sickness. The instrument also has potential as a tool to guide the oxygen-prebreathing schedules of astronauts; high-altitude aviators; individuals who undertake high-altitude, low-opening (HALO) parachute jumps; and others at risk of decompression sickness. For example, an individual at serious risk of decompression sickness because of high concentrations of extravascular microscopic <span class="hlt">bubbles</span> could be given a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980206465','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980206465"><span><span class="hlt">Bubble</span>, Drop and Particle Unit (BDPU)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1998-01-01</p> <p>This section of the Life and Microgravity Spacelab (LMS) publication includes the following articles entitled: (1) Oscillatory Thermocapillary Instability; (2) Thermocapillary Convection in Multilayer Systems; (3) <span class="hlt">Bubble</span> and Drop Interaction with Solidification Front; (4) A Liquid Electrohydrodynamics Experiment; (5) Boiling on Small Plate Heaters under Microgravity and a Comparison with Earth Gravity; (6) Thermocapillary Migration and Interactions of <span class="hlt">Bubbles</span> and Drops; and (7) Nonlinear Surface Tension Driven <span class="hlt">Bubble</span> Migration</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26762545','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26762545"><span>Carbon dioxide induced <span class="hlt">bubble</span> formation in a CH4-CO2-H2O ternary system: a molecular dynamics simulation study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sujith, K S; Ramachandran, C N</p> <p>2016-02-07</p> <p>The extraction of methane from its hydrates using carbon dioxide involves the decomposition of the hydrate resulting in a CH4-CO2-H2O ternary solution. Using classical molecular dynamics simulations, we investigate the evolution of dissolved gas molecules in the ternary system at different concentrations of CO2. Various compositions considered in the present study resemble the solution formed during the decomposition of methane hydrates at the initial stages of the extraction process. We find that the presence of CO2 aids the formation of CH4 <span class="hlt">bubbles</span> by causing its early nucleation. Elucidation of the composition of the <span class="hlt">bubble</span> revealed that in ternary solutions with high concentration of CO2, mixed gas <span class="hlt">bubbles</span> composed of CO2 and CH4 are formed. To understand the role of CO2 in the nucleation of CH4 <span class="hlt">bubbles</span>, the structure of the <span class="hlt">bubble</span> formed was analyzed, which revealed that there is an accumulation of CO2 at the interface of the <span class="hlt">bubble</span> and the surrounding water. The aggregation of CO2 at the <span class="hlt">bubble</span>-water interface occurs predominantly when the concentration of CO2 is high. Radial distribution function for the CH4-CO2 pair indicates that there is an increasingly favorable direct contact between dissolved CH4 and CO2 molecules in the <span class="hlt">bubble</span>-water interface. It is also observed that the presence of CO2 at the interface results in the decrease in surface tension. Thus, CO2 leads to greater stability of the <span class="hlt">bubble</span>-water interface thereby bringing down the critical size of the <span class="hlt">bubble</span> nuclei. The results suggest that a <span class="hlt">rise</span> in concentration of CO2 helps in the removal of dissolved CH4 thereby preventing the accumulation of methane in the liquid phase. Thus, the presence of CO2 is predicted to assist the decomposition of methane hydrates in the initial stages of the replacement process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017TCry...11.1333L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017TCry...11.1333L"><span>Sonar gas flux estimation by <span class="hlt">bubble</span> insonification: application to methane <span class="hlt">bubble</span> flux from seep areas in the outer Laptev Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leifer, Ira; Chernykh, Denis; Shakhova, Natalia; Semiletov, Igor</p> <p>2017-06-01</p> <p>Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered <span class="hlt">bubble</span> plumes from 40 m depth with fluxes spanning 0.019 to 1.1 L s-1 to derive the in situ calibration curve (Q(σ)). These nonlinear curves related flux (Q) to sonar return (σ) for a multibeam echosounder (MBES) and a single-beam echosounder (SBES) for a range of depths. The analysis demonstrated significant multiple <span class="hlt">bubble</span> acoustic scattering - precluding the use of a theoretical approach to derive Q(σ) from the product of the <span class="hlt">bubble</span> σ(r) and the <span class="hlt">bubble</span> size distribution where r is <span class="hlt">bubble</span> radius. The <span class="hlt">bubble</span> plume σ occurrence probability distribution function (Ψ(σ)) with respect to Q found Ψ(σ) for weak σ well described by a power law that likely correlated with small-<span class="hlt">bubble</span> dispersion and was strongly depth dependent. Ψ(σ) for strong σ was largely depth independent, consistent with <span class="hlt">bubble</span> plume behavior where large <span class="hlt">bubbles</span> in a plume remain in a focused core. Ψ(σ) was bimodal for all but the weakest plumes. Q(σ) was applied to sonar observations of natural arctic Laptev Sea seepage after accounting for volumetric change with numerical <span class="hlt">bubble</span> plume simulations. Simulations addressed different depths and gases between calibration and seep plumes. Total mass fluxes (Qm) were 5.56, 42.73, and 4.88 mmol s-1 for MBES data with good to reasonable agreement (4-37 %) between the SBES and MBES systems. The seepage flux occurrence probability distribution function (Ψ(Q)) was bimodal, with weak Ψ(Q) in each seep area well described by a power law, suggesting primarily minor <span class="hlt">bubble</span> plumes. The seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SPIE.6051E..1DT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SPIE.6051E..1DT"><span>Quantitative evaluation method of the <span class="hlt">bubble</span> structure of sponge cake by using morphology image processing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tatebe, Hironobu; Kato, Kunihito; Yamamoto, Kazuhiko; Katsuta, Yukio; Nonaka, Masahiko</p> <p>2005-12-01</p> <p>Now a day, many evaluation methods for the food industry by using image processing are proposed. These methods are becoming new evaluation method besides the sensory test and the solid-state measurement that are using for the quality evaluation. An advantage of the image processing is to be able to evaluate objectively. The goal of our research is structure evaluation of sponge cake by using image processing. In this paper, we propose a feature extraction method of the bobble structure in the sponge cake. Analysis of the <span class="hlt">bubble</span> structure is one of the important properties to understand <span class="hlt">characteristics</span> of the cake from the image. In order to take the cake image, first we cut cakes and measured that's surface by using the CIS scanner. Because the depth of field of this type scanner is very shallow, the <span class="hlt">bubble</span> region of the surface has low gray scale values, and it has a feature that is blur. We extracted <span class="hlt">bubble</span> regions from the surface images based on these features. First, input image is binarized, and the feature of <span class="hlt">bubble</span> is extracted by the morphology analysis. In order to evaluate the result of feature extraction, we compared correlation with "Size of the <span class="hlt">bubble</span>" of the sensory test result. From a result, the <span class="hlt">bubble</span> extraction by using morphology analysis gives good correlation. It is shown that our method is as well as the subjectivity evaluation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29676748','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29676748"><span>Study on <span class="hlt">bubble</span> column humidification and dehumidification system for coal mine wastewater treatment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gao, Penghui; Zhang, Meng; Du, Yuji; Cheng, Bo; Zhang, Donghai</p> <p>2018-04-01</p> <p>Water is important resource for human survival and development. Coal mine wastewater (CMW) is a byproduct of the process of coal mining, which is about 7.0 × 10 10 m 3 in China in 2016. Considering coal mine wastewater includes different ingredients, a new <span class="hlt">bubble</span> column humidification and dehumidification system is proposed for CMW treatment. The system is mainly composed of a <span class="hlt">bubble</span> column humidification and dehumidification unit, solar collector, fan and water tank, in which air is used as a circulating medium. The system can avoid water treatment component blocking for reverse osmosis (RO) and multi effect distillation (MED) dealing with CMW, and produce water greenly. By analysis of heat and mass transfer, the effects of solar radiation, air <span class="hlt">bubble</span> velocity and mine water temperature on water treatment production <span class="hlt">characteristics</span> are studied. Compared with other methods, thermal energy consumption (TEC) of <span class="hlt">bubble</span> column humidification and dehumidification (BCHD) is moderate, which is about 700 kJ/kg (powered by solar energy). The results would provide a new method for CMW treatment and insights into the efficient coal wastewater treatment, besides, it helps to identify the parameters for the technology development in mine water treatment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25799328','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25799328"><span>Jumping acoustic <span class="hlt">bubbles</span> on lipid bilayers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Der Loughian, Christelle; Muleki Seya, Pauline; Pirat, Christophe; Inserra, Claude; Béra, Jean-Christophe; Rieu, Jean-Paul</p> <p>2015-05-07</p> <p>In the context of sonoporation, we use supported lipid bilayers as a model for biological membranes and investigate the interactions between the bilayer and microbubbles induced by ultrasound. Among the various types of damage caused by <span class="hlt">bubbles</span> on the surface, our experiments exhibit a singular dynamic interaction process where <span class="hlt">bubbles</span> are jumping on the bilayer, forming a necklace pattern of alteration on the membrane. This phenomenon was explored with different time and space resolutions and, based on our observations, we propose a model for a microbubble subjected to the combined action of van der Waals, acoustic and hydrodynamic forces. Describing the repeated jumps of the <span class="hlt">bubble</span>, this model explains the lipid exchanges between the <span class="hlt">bubble</span> and bilayer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22311337-detecting-vapour-bubbles-simulations-metastable-water','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22311337-detecting-vapour-bubbles-simulations-metastable-water"><span>Detecting vapour <span class="hlt">bubbles</span> in simulations of metastable water</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>González, Miguel A.; Abascal, Jose L. F.; Valeriani, Chantal, E-mail: christoph.dellago@univie.ac.at, E-mail: cvaleriani@quim.ucm.es</p> <p>2014-11-14</p> <p>The investigation of cavitation in metastable liquids with molecular simulations requires an appropriate definition of the volume of the vapour <span class="hlt">bubble</span> forming within the metastable liquid phase. Commonly used approaches for <span class="hlt">bubble</span> detection exhibit two significant flaws: first, when applied to water they often identify the voids within the hydrogen bond network as <span class="hlt">bubbles</span> thus masking the signature of emerging <span class="hlt">bubbles</span> and, second, they lack thermodynamic consistency. Here, we present two grid-based methods, the M-method and the V-method, to detect <span class="hlt">bubbles</span> in metastable water specifically designed to address these shortcomings. The M-method incorporates information about neighbouring grid cells to distinguishmore » between liquid- and vapour-like cells, which allows for a very sensitive detection of small <span class="hlt">bubbles</span> and high spatial resolution of the detected <span class="hlt">bubbles</span>. The V-method is calibrated such that its estimates for the <span class="hlt">bubble</span> volume correspond to the average change in system volume and are thus thermodynamically consistent. Both methods are computationally inexpensive such that they can be used in molecular dynamics and Monte Carlo simulations of cavitation. We illustrate them by computing the free energy barrier and the size of the critical <span class="hlt">bubble</span> for cavitation in water at negative pressure.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010024912','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010024912"><span>Marangoni Effects on Near-<span class="hlt">Bubble</span> Microscale Transport During Boiling of Binary Fluid Mixtures</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>V. Carey; Sun, C.; Carey, V. P.</p> <p>2000-01-01</p> <p>In earlier investigations, Marangoni effects were observed to be the dominant mechanism of boiling transport in 2-propanol/water mixtures under reduced gravity conditions. In this investigation we have examined the mechanisms of binary mixture boiling by exploring the transport near a single <span class="hlt">bubble</span> generated in a binary mixture between a heated surface and cold surface. The temperature field created in the liquid around the <span class="hlt">bubble</span> produces vaporization over the portion of its interface near the heated surface and condensation over portions of its interface near the cold surface. Experiments were conducted using different mixtures of water and 2-propanol under 1g conditions and under reduced gravity conditions aboard the KC135 aircraft. Since 2-propanol is more volatile than water, there is a lower concentration of 2-propanol near the hot surface and a higher concentration of 2-propanol near the cold plate relative to the bulk quantity. This difference in interface concentration gives <span class="hlt">rise</span> to strong Marangoni effects that move liquid toward the hot plate in the near <span class="hlt">bubble</span> region for 2-propanol and water mixtures. In the experiments in this study, the pressure of the test system was maintained at about 5 kPa to achieve the full spectrum of boiling behavior (nucleate boiling, critical heat flux and film boiling) at low temperature and heat flux levels. Heat transfer data and visual documentation of the <span class="hlt">bubble</span> shape were extracted from the experimental results. In the 1-g experiments at moderate to high heat flux levels, the <span class="hlt">bubble</span> was observed to grow into a mushroom shape with a larger top portion near the cold plate due to the buoyancy effect. The shape of the <span class="hlt">bubble</span> was somewhat affected by the cold plate subcooling and the superheat of the heated surface. At low superheat levels for the heated surface, several active nucleation sites were observed, and the vapor stems from them merged to form a larger <span class="hlt">bubble</span>. The generation rate of vapor is moderate in this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010MMTB...41.1006V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010MMTB...41.1006V"><span>Morphology of Two-Phase Layers with Large <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vékony, Klára; Kiss, László I.</p> <p>2010-10-01</p> <p>The understanding of formation and movement of <span class="hlt">bubbles</span> nucleated during aluminum reduction is essential for a good control of the electrolysis process. In our experiments, we filmed and studied the formation of a <span class="hlt">bubble</span> layer under the anode in a real-size air-water electrolysis cell model. The maximum height of the <span class="hlt">bubbles</span> was found to be up to 2 cm because of the presence of the so-called Fortin <span class="hlt">bubbles</span>. Also, the mean height of the <span class="hlt">bubble</span> layer was found to be much higher than published previously. The Fortin <span class="hlt">bubbles</span> were investigated more closely, and their shape was found to be induced by a gravity wave formed at the gas-liquid interface. In addition, large <span class="hlt">bubbles</span> were always observed to break up into smaller parts right before escaping from under the anode. This breakup and escape led to a large momentum transfer in the bath.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19656520','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19656520"><span>The detachment of particles from coalescing <span class="hlt">bubble</span> pairs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ata, Seher</p> <p>2009-10-15</p> <p>This paper is concerned with the detachment of particles from coalescing <span class="hlt">bubble</span> pairs. Two <span class="hlt">bubbles</span> were generated at adjacent capillaries and coated with hydrophobic glass particles of mean diameter 66 microm. The <span class="hlt">bubbles</span> were then positioned next to each other until the thin liquid film between them ruptured. The particles that dropped from the <span class="hlt">bubble</span> surface during the coalescence process were collected and measured. The coalescence process was very vigorous and observations showed that particles detached from the <span class="hlt">bubble</span> surfaces as a result of the oscillations caused by coalescence. The attached particles themselves and, to some extent the presence of the surfactant had a damping affect on the <span class="hlt">bubble</span> oscillation, which played a decisive role on the particle detachment phenomena. The behaviour of particles on the surfaces of the <span class="hlt">bubbles</span> during coalescence was described, and implications of results for the flotation process were discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010004280','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010004280"><span><span class="hlt">Bubble</span> Generation in a Flowing Liquid Medium and Resulting Two-Phase Flow in Microgravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pais, S. C.; Kamotani, Y.; Bhunia, A.; Ostrach, S.</p> <p>1999-01-01</p> <p> forming <span class="hlt">bubble</span> decreases, as the superficial liquid velocity is in-creased. Furthermore, it is shown that the void fraction of the resulting two-phase flow increases with volumetric gas flow rate Q(sub d), pipe diameter and gas injection nozzle diameter, while they decrease with surrounding liquid flow. The important role played by flowing liquid in detaching <span class="hlt">bubbles</span> in a reduced gravity environment is thus emphasized. We observe that the void fraction can be accurately controlled by using single nozzle gas injection, rather than by employing multiple port injection, since the later system gives <span class="hlt">rise</span> to unpredictable coalescence of adjacent <span class="hlt">bubbles</span>. It is of interest to note that empirical <span class="hlt">bubble</span> size and corresponding void fraction are somewhat smaller for the co-flow geometry than the cross-flow configuration at similar flow conditions with similar pipe and nozzle diameters. In order to supplement the empirical data, a theoretical model is employed to study single <span class="hlt">bubble</span> generation in the dynamic (Q(sub d) = 1 - 1000 cu cm/s) and <span class="hlt">bubbly</span> flow regime within the framework of the co-flow configuration. This theoretical model is based on an overall force balance acting on the <span class="hlt">bubble</span> during the two stages of generation, namely the expansion and the detachment stage. Two sets of forces, one aiding and the other inhibiting <span class="hlt">bubble</span> detachment are identified. Under conditions of reduced gravity, gas momentum flux enhances, while the surface tension force at the air injection nozzle tip inhibits <span class="hlt">bubble</span> detachment. In parallel, liquid drag and inertia can act as both attaching and detaching forces, depending on the relative velocity of the <span class="hlt">bubble</span> with respect to the surrounding liquid. Predictions of the theoretical model compare well with our experimental results. However, at higher superficial liquid velocities, as the <span class="hlt">bubble</span> loses its spherical form, empirical <span class="hlt">bubble</span> size no longer matches the theoretical predictions. In summary, we have developed a combined experimental and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25772819','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25772819"><span>Contact <span class="hlt">bubble</span> bilayers with flush drainage.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Iwamoto, Masayuki; Oiki, Shigetoshi</p> <p>2015-03-16</p> <p>Planar lipid bilayers have been used to form stable bilayers into which membrane proteins are reconstituted for measurements of their function under an applied membrane potential. Recently, a lipid bilayer membrane is formed by the apposition of two monolayers that line an oil-electrolyte interface. Here, a bilayer membrane system is developed with picoliter <span class="hlt">bubbles</span> under mechanically and chemically manipulable conditions. A water <span class="hlt">bubble</span> lined with a phospholipid monolayer is blown from a glass pipette into an oil phase. Two blowing pipettes are manipulated, and <span class="hlt">bubbles</span> (each with a diameter of ~ 50 μm) are held side by side to form a bilayer, which is termed a contact <span class="hlt">bubble</span> bilayer. With the electrode implemented in the blowing pipette, currents through the bilayer are readily measured. The intra-<span class="hlt">bubble</span> pressure is varied with the pressure-controller, leading to various sizes of the <span class="hlt">bubble</span> and the membrane area. A rapid solution exchange system is developed by introducing additional pressure-driven injection pipettes, and the blowing pipette works as a drain. The solution is exchanged within 20 ms. Also, an asymmetric membrane with different lipid composition of each leaflet is readily formed. Example applications of this versatile method are presented to characterize the function of ion channels.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4360637','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4360637"><span>Contact <span class="hlt">Bubble</span> Bilayers with Flush Drainage</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Iwamoto, Masayuki; Oiki, Shigetoshi</p> <p>2015-01-01</p> <p>Planar lipid bilayers have been used to form stable bilayers into which membrane proteins are reconstituted for measurements of their function under an applied membrane potential. Recently, a lipid bilayer membrane is formed by the apposition of two monolayers that line an oil-electrolyte interface. Here, a bilayer membrane system is developed with picoliter <span class="hlt">bubbles</span> under mechanically and chemically manipulable conditions. A water <span class="hlt">bubble</span> lined with a phospholipid monolayer is blown from a glass pipette into an oil phase. Two blowing pipettes are manipulated, and <span class="hlt">bubbles</span> (each with a diameter of ~ 50 μm) are held side by side to form a bilayer, which is termed a contact <span class="hlt">bubble</span> bilayer. With the electrode implemented in the blowing pipette, currents through the bilayer are readily measured. The intra-<span class="hlt">bubble</span> pressure is varied with the pressure-controller, leading to various sizes of the <span class="hlt">bubble</span> and the membrane area. A rapid solution exchange system is developed by introducing additional pressure-driven injection pipettes, and the blowing pipette works as a drain. The solution is exchanged within 20 ms. Also, an asymmetric membrane with different lipid composition of each leaflet is readily formed. Example applications of this versatile method are presented to characterize the function of ion channels. PMID:25772819</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25964033','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25964033"><span>Flying after diving: should recommendations be reviewed? In-flight echocardiographic study in <span class="hlt">bubble</span>-prone and <span class="hlt">bubble</span>-resistant divers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cialoni, Danilo; Pieri, Massimo; Balestra, Costantino; Marroni, Alessandro</p> <p>2015-03-01</p> <p>Inert gas accumulated after multiple recreational dives can generate tissue supersaturation and <span class="hlt">bubble</span> formation when ambient pressure decreases. We hypothesized that this could happen even if divers respected the currently recommended 24-hour pre-flight surface interval (PFSI). We performed transthoracic echocardiography (TTE) on a group of 56 healthy scuba divers (39 male, 17 female) as follows: first echo--during the outgoing flight, no recent dives; second echo--before boarding the return flight, after a multiday diving week in the tropics and a 24-hour PFSI; third echo--during the return flight at 30, 60 and 90 minutes after take-off. TTE was also done after every dive during the week's diving. Divers were divided into three groups according to their '<span class="hlt">bubble</span>-proneness': non-bubblers, occasional bubblers and consistent bubblers. During the diving, 23 subjects never developed <span class="hlt">bubbles</span>, 17 only occasionally and 16 subjects produced <span class="hlt">bubbles</span> every day and after every dive. <span class="hlt">Bubbles</span> on the return flight were observed in eight of the 56 divers (all from the 'bubblers' group). Two subjects who had the highest <span class="hlt">bubble</span> scores during the diving were advised not to make the last dive (increasing their PFSI to approximately 36 hours), and did not demonstrate <span class="hlt">bubbles</span> on the return flight. Even though a 24-hour PFSI is recommended on the basis of clinical trials showing a low risk of decompression sickness (DCS), the presence of venous gas <span class="hlt">bubbles</span> in-flight in eight of 56 divers leads us to suspect that in real-life situations DCS risk after such a PFSI is not zero.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28191980','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28191980"><span>Interaction Mechanisms between Air <span class="hlt">Bubble</span> and Molybdenite Surface: Impact of Solution Salinity and Polymer Adsorption.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xie, Lei; Wang, Jingyi; Yuan, Duowei; Shi, Chen; Cui, Xin; Zhang, Hao; Liu, Qi; Liu, Qingxia; Zeng, Hongbo</p> <p>2017-03-07</p> <p>The surface <span class="hlt">characteristics</span> of molybdenite (MoS 2 ) such as wettability and surface interactions have attracted much research interest in a wide range of engineering applications, such as froth flotation. In this work, a <span class="hlt">bubble</span> probe atomic force microscope (AFM) technique was employed to directly measure the interaction forces between an air <span class="hlt">bubble</span> and molybdenite mineral surface before/after polymer (i.e., guar gum) adsorption treatment. The AFM imaging showed that the polymer coverage on the surface of molybdenite could achieve ∼5.6, ∼44.5, and ∼100% after conditioning in 1, 5, and 10 ppm polymer solution, respectively, which coincided with the polymer coverage results based on contact angle measurements. The electrolyte concentration and surface treatment by polymer adsorption were found to significantly affect <span class="hlt">bubble</span>-mineral interaction and attachment. The experimental force results on <span class="hlt">bubble</span>-molybdenite (without polymer treatment) agreed well with the calculations using a theoretical model based on the Reynolds lubrication theory and augmented Young-Laplace equation including the effect of disjoining pressure. The overall surface repulsion was enhanced when the NaCl concentration decreased from 100 to 1 mM, which inhibited the <span class="hlt">bubble</span>-molybdenite attachment. After conditioning the molybdenite surface in 1 ppm polymer solution, it was more difficult for air <span class="hlt">bubbles</span> to attach to the molybdenite surface due to the weakened hydrophobic interaction with a shorter decay length. Increasing the polymer concentration to 5 ppm effectively inhibited <span class="hlt">bubble</span> attachment on mineral surface, which was mainly due to the much reduced hydrophobic interaction as well as the additional steric repulsion between the extended polymer chains and <span class="hlt">bubble</span> surface. The results provide quantitative information on the interaction mechanism between air <span class="hlt">bubbles</span> and molybdenite mineral surfaces on the nanoscale, with useful implications for the development of effective polymer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23670058','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23670058"><span><span class="hlt">Bubble</span> gate for in-plane flow control.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Oskooei, Ali; Abolhasani, Milad; Günther, Axel</p> <p>2013-07-07</p> <p>We introduce a miniature gate valve as a readily implementable strategy for actively controlling the flow of liquids on-chip, within a footprint of less than one square millimetre. <span class="hlt">Bubble</span> gates provide for simple, consistent and scalable control of liquid flow in microchannel networks, are compatible with different bulk microfabrication processes and substrate materials, and require neither electrodes nor moving parts. A <span class="hlt">bubble</span> gate consists of two microchannel sections: a liquid-filled channel and a gas channel that intercepts the liquid channel to form a T-junction. The open or closed state of a <span class="hlt">bubble</span> gate is determined by selecting between two distinct gas pressure levels: the lower level corresponds to the "open" state while the higher level corresponds to the "closed" state. During closure, a gas <span class="hlt">bubble</span> penetrates from the gas channel into the liquid, flanked by a column of equidistantly spaced micropillars on each side, until the flow of liquid is completely obstructed. We fabricated <span class="hlt">bubble</span> gates using single-layer soft lithographic and bulk silicon micromachining procedures and evaluated their performance with a combination of theory and experimentation. We assessed the dynamic behaviour during more than 300 open-and-close cycles and report the operating pressure envelope for different <span class="hlt">bubble</span> gate configurations and for the working fluids: de-ionized water, ethanol and a biological buffer. We obtained excellent agreement between the experimentally determined <span class="hlt">bubble</span> gate operational envelope and a theoretical prediction based on static wetting behaviour. We report case studies that serve to illustrate the utility of <span class="hlt">bubble</span> gates for liquid sampling in single and multi-layer microfluidic devices. Scalability of our strategy was demonstrated by simultaneously addressing 128 <span class="hlt">bubble</span> gates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19756233','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19756233"><span>Numerical simulations of non-spherical <span class="hlt">bubble</span> collapse.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johnsen, Eric; Colonius, Tim</p> <p>2009-06-01</p> <p>A high-order accurate shock- and interface-capturing scheme is used to simulate the collapse of a gas <span class="hlt">bubble</span> in water. In order to better understand the damage caused by collapsing <span class="hlt">bubbles</span>, the dynamics of the shock-induced and Rayleigh collapse of a <span class="hlt">bubble</span> near a planar rigid surface and in a free field are analysed. Collapse times, <span class="hlt">bubble</span> displacements, interfacial velocities and surface pressures are quantified as a function of the pressure ratio driving the collapse and of the initial <span class="hlt">bubble</span> stand-off distance from the wall; these quantities are compared to the available theory and experiments and show good agreement with the data for both the <span class="hlt">bubble</span> dynamics and the propagation of the shock emitted upon the collapse. Non-spherical collapse involves the formation of a re-entrant jet directed towards the wall or in the direction of propagation of the incoming shock. In shock-induced collapse, very high jet velocities can be achieved, and the finite time for shock propagation through the <span class="hlt">bubble</span> may be non-negligible compared to the collapse time for the pressure ratios of interest. Several types of shock waves are generated during the collapse, including precursor and water-hammer shocks that arise from the re-entrant jet formation and its impact upon the distal side of the <span class="hlt">bubble</span>, respectively. The water-hammer shock can generate very high pressures on the wall, far exceeding those from the incident shock. The potential damage to the neighbouring surface is quantified by measuring the wall pressure. The range of stand-off distances and the surface area for which amplification of the incident shock due to <span class="hlt">bubble</span> collapse occurs is determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2743482','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2743482"><span>Numerical simulations of non-spherical <span class="hlt">bubble</span> collapse</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>JOHNSEN, ERIC; COLONIUS, TIM</p> <p>2009-01-01</p> <p>A high-order accurate shock- and interface-capturing scheme is used to simulate the collapse of a gas <span class="hlt">bubble</span> in water. In order to better understand the damage caused by collapsing <span class="hlt">bubbles</span>, the dynamics of the shock-induced and Rayleigh collapse of a <span class="hlt">bubble</span> near a planar rigid surface and in a free field are analysed. Collapse times, <span class="hlt">bubble</span> displacements, interfacial velocities and surface pressures are quantified as a function of the pressure ratio driving the collapse and of the initial <span class="hlt">bubble</span> stand-off distance from the wall; these quantities are compared to the available theory and experiments and show good agreement with the data for both the <span class="hlt">bubble</span> dynamics and the propagation of the shock emitted upon the collapse. Non-spherical collapse involves the formation of a re-entrant jet directed towards the wall or in the direction of propagation of the incoming shock. In shock-induced collapse, very high jet velocities can be achieved, and the finite time for shock propagation through the <span class="hlt">bubble</span> may be non-negligible compared to the collapse time for the pressure ratios of interest. Several types of shock waves are generated during the collapse, including precursor and water-hammer shocks that arise from the re-entrant jet formation and its impact upon the distal side of the <span class="hlt">bubble</span>, respectively. The water-hammer shock can generate very high pressures on the wall, far exceeding those from the incident shock. The potential damage to the neighbouring surface is quantified by measuring the wall pressure. The range of stand-off distances and the surface area for which amplification of the incident shock due to <span class="hlt">bubble</span> collapse occurs is determined. PMID:19756233</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F8001A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F8001A"><span>Inertial collapse of <span class="hlt">bubble</span> pairs near a solid surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alahyari Beig, Shahaboddin; Johnsen, Eric</p> <p>2017-11-01</p> <p>Cavitation occurs in a variety of applications ranging from naval structures to biomedical ultrasound. One important consequence is structural damage to neighboring surfaces following repeated inertial collapse of vapor <span class="hlt">bubbles</span>. Although the mechanical loading produced by the collapse of a single <span class="hlt">bubble</span> has been widely investigated, less is known about the detailed dynamics of the collapse of multiple <span class="hlt">bubbles</span>. In such a problem, the <span class="hlt">bubble-bubble</span> interactions typically affect the dynamics, e.g., by increasing the non-sphericity of the <span class="hlt">bubbles</span> and amplifying/hindering the collapse intensity depending on the flow parameters. Here, we quantify the effects of <span class="hlt">bubble-bubble</span> interactions on the <span class="hlt">bubble</span> dynamics, as well as the pressures/temperatures produced by the collapse of a pair of gas <span class="hlt">bubbles</span> near a rigid surface. We perform high-resolution simulations of this problem by solving the three-dimensional compressible Navier-Stokes equations for gas/liquid flows. The results are used to investigate the non-spherical <span class="hlt">bubble</span> dynamics and characterize the pressure and temperature fields based on the relevant parameters entering the problem: stand-off distance, geometrical configuration (angle, relative size, distance), collapse strength. This research was supported in part by ONR Grant N00014-12-1-0751 and NSF Grant CBET 1253157.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19228030','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19228030"><span><span class="hlt">Bubble</span> snap-off and capillary-back pressure during counter-current spontaneous imbibition into model pores.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Unsal, Evren; Mason, Geoffrey; Morrow, Norman R; Ruth, Douglas W</p> <p>2009-04-09</p> <p>A previous paper (Unsal, E.; Mason, G.; Ruth, D. W.; Morrow, N. R. J. Colloid Interface Sci. 2007, 315, 200-209) reported experiments involving counter-current spontaneous imbibition into a model pore system consisting of a rod in an angled slot covered by a glass plate. Such an arrangement gives two tubes with different cross-sections (both size and shape) with an interconnection through the gap between the rod and the plate. In the previous experiments, the wetting phase advanced in the small tube and nonwetting phase retreated in the large tube. No <span class="hlt">bubbles</span> were formed. In this paper, we study experimentally and theoretically the formation of <span class="hlt">bubbles</span> at the open end of the large tube and their subsequent snap-off. Such <span class="hlt">bubbles</span> reduce the capillary back pressure produced by the larger tube and can thus have an effect on the local rate of imbibition. In the model pore system, the rod was either in contact with the glass, forming two independent tubes, or the rod was spaced from the glass to allow cross-flow between the tubes. For small gaps, there were three distinct menisci. The one with the highest curvature was between the rod and the plate. The next most highly curved was in the smaller tube, and the least highly curved meniscus was in the large tube and this was the tube from which the <span class="hlt">bubbles</span> developed. The pressure in the dead end of the system was recorded during imbibition. Once the <span class="hlt">bubble</span> starts to form outside of the tube, the pressure drops rapidly and then steadies. After the <span class="hlt">bubble</span> snaps off, the pressure <span class="hlt">rises</span> to almost the initial value and stays essentially constant until the next <span class="hlt">bubble</span> starts to form. After snap-off, the meniscus in the large tube appears to invade the large tube for some distance. The snap-off is the result of capillary instability; it takes place significantly inside the large tube with flow of wetting phase moving in the angular corners. As imbibition into the small tube progresses, the rate of imbibition decreases and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70148465','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70148465"><span>Bursting the <span class="hlt">bubble</span> of melt inclusions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lowenstern, Jacob B.</p> <p>2015-01-01</p> <p>Most silicate melt inclusions (MI) contain <span class="hlt">bubbles</span>, whose significance has been alternately calculated, pondered, and ignored, but rarely if ever directly explored. Moore et al. (2015) analyze the <span class="hlt">bubbles</span>, as well as their host glasses, and conclude that they often hold the preponderance of CO2 in the MI. Their findings entreat future researchers to account for the presence of <span class="hlt">bubbles</span> in MI when calculating volatile budgets, saturation pressures, and eruptive flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860000110&hterms=fast+memory&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfast%2Bmemory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860000110&hterms=fast+memory&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfast%2Bmemory"><span>Fast Initialization of <span class="hlt">Bubble</span>-Memory Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Looney, K. T.; Nichols, C. D.; Hayes, P. J.</p> <p>1986-01-01</p> <p>Improved scheme several orders of magnitude faster than normal initialization scheme. State-of-the-art commercial <span class="hlt">bubble</span>-memory device used. Hardware interface designed connects controlling microprocessor to bubblememory circuitry. System software written to exercise various functions of <span class="hlt">bubble</span>-memory system in comparison made between normal and fast techniques. Future implementations of approach utilize E2PROM (electrically-erasable programable read-only memory) to provide greater system flexibility. Fastinitialization technique applicable to all <span class="hlt">bubble</span>-memory devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ApJ...847...94S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ApJ...847...94S"><span>Buoyant AGN <span class="hlt">Bubbles</span> in the Quasi-isothermal Potential of NGC 1399</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Yuanyuan; Nulsen, Paul E. J.; Kraft, Ralph P.; Forman, William R.; Jones, Christine; Irwin, Jimmy A.; Randall, Scott W.; Churazov, Eugene</p> <p>2017-10-01</p> <p>The Fornax Cluster is a low-mass cool-core galaxy cluster. We present a deep Chandra study of NGC 1399, the central dominant elliptical galaxy of Fornax. The cluster center harbors two symmetric X-ray cavities coincident with a pair of radio lobes fed by two collimated jets along a north-south axis. A temperature map reveals that the active galactic nucleus (AGN) outburst has created a channel filled with cooler gas out to a radius of 10 kpc. The cavities are surrounded by cool bright rims and filaments that may have been lifted from smaller radii by the buoyant <span class="hlt">bubbles</span>. X-ray imaging suggests a potential ghost <span class="hlt">bubble</span> of ≳5 kpc diameter to the northwest. We find that the amount of gas lifted by AGN <span class="hlt">bubbles</span> is comparable to that which would otherwise cool, demonstrating that AGN-driven outflow is effective in offsetting cooling in low-mass clusters. The cluster cooling timescale is > 30 times longer than the dynamical timescale, which is consistent with the lack of cold molecular gas at the cluster center. The X-ray hydrostatic mass is consistent within 10%, with the total mass derived from the optical data. The observed entropy profile <span class="hlt">rises</span> linearly, following a steeper slope than that observed at the centers of massive clusters; gas shed by stars in NGC 1399 may be incorporated in the hot phase. However, it is far-fetched for supernova-driven outflow to produce and maintain the thermal distribution in NGC 1399, and it is in tension with the metal content in the hot gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998NewA....3...57Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998NewA....3...57Z"><span>1D gasdynamics of wind-blown <span class="hlt">bubbles</span>: effects of thermal conduction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhekov, S. A.; Myasnikov, A. V.</p> <p>1998-03-01</p> <p>Gasdynamic properties of the wind-blown <span class="hlt">bubbles</span> are considered in the framework of the 1D spherically symmetric flow. The model self-consistently takes into account the optically-thin-plasma cooling and the electron thermal conduction. The numerical method used in calculations is described in details. A comparison with the existing self-similar solution is provided. It is shown that the self-similar solution gives a relatively well representation of the hot-<span class="hlt">bubble</span> interior and could be used for estimations of some of its spectral <span class="hlt">characteristics</span>. However, it is also shown that the thermal conduction in combination with the cooling may cause additional multiple shocks to appear in the interaction region and the analysis of the nature of these shocks is provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFD.E4005P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFD.E4005P"><span>Bursting the Taylor cone <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pan, Zhao; Truscott, Tadd</p> <p>2014-11-01</p> <p>A soap <span class="hlt">bubble</span> fixed on a surface and placed in an electric field will take on the shape of a cone rather than constant curvature (dome) when the electrical field is not present. The phenomenon was introduced by J. Zeleny (1917) and studied extensively by C.T. Wilson & G.I. Taylor (1925). We revisit the Taylor cone problem by studying the deformation and bursting of soap <span class="hlt">bubbles</span> in a point charge electric field. A single <span class="hlt">bubble</span> takes on the shape of a cone in the electric field and a high-speed camera equipped with a micro-lens is used to observe the unsteady dynamics at the tip. Rupture occurs as a very small piece of the tip is torn away from the <span class="hlt">bubble</span> toward the point charge. Based on experiments, a theoretical model is developed that predicts when rupture should occur. This study may help in the design of foam-removal techniques in engineering and provide a better understanding of an electrified air-liquid interface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvL.120r6104H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvL.120r6104H"><span>Raman Spectral Band Oscillations in Large Graphene <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huang, Yuan; Wang, Xiao; Zhang, Xu; Chen, Xianjue; Li, Baowen; Wang, Bin; Huang, Ming; Zhu, Chongyang; Zhang, Xuewei; Bacsa, Wolfgang S.; Ding, Feng; Ruoff, Rodney S.</p> <p>2018-05-01</p> <p>Raman spectra of large graphene <span class="hlt">bubbles</span> showed size-dependent oscillations in spectral intensity and frequency, which originate from optical standing waves formed in the vicinity of the graphene surface. At a high laser power, local heating can lead to oscillations in the Raman frequency and also create a temperature gradient in the <span class="hlt">bubble</span>. Based on Raman data, the temperature distribution within the graphene <span class="hlt">bubble</span> was calculated, and it is shown that the heating effect of the laser is reduced when moving from the center of a <span class="hlt">bubble</span> to its edge. By studying graphene <span class="hlt">bubbles</span>, both the thermal conductivity and chemical reactivity of graphene were assessed. When exposed to hydrogen plasma, areas with <span class="hlt">bubbles</span> are found to be more reactive than flat graphene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25994696','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25994696"><span>Two types of nonlinear wave equations for diffractive beams in <span class="hlt">bubbly</span> liquids with nonuniform <span class="hlt">bubble</span> number density.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kanagawa, Tetsuya</p> <p>2015-05-01</p> <p>This paper theoretically treats the weakly nonlinear propagation of diffracted sound beams in nonuniform <span class="hlt">bubbly</span> liquids. The spatial distribution of the number density of the <span class="hlt">bubbles</span>, initially in a quiescent state, is assumed to be a slowly varying function of the spatial coordinates; the amplitude of variation is assumed to be small compared to the mean number density. A previous derivation method of nonlinear wave equations for plane progressive waves in uniform <span class="hlt">bubbly</span> liquids [Kanagawa, Yano, Watanabe, and Fujikawa (2010). J. Fluid Sci. Technol. 5(3), 351-369] is extended to handle quasi-plane beams in weakly nonuniform <span class="hlt">bubbly</span> liquids. The diffraction effect is incorporated by adding a relation that scales the circular sound source diameter to the wavelength into the original set of scaling relations composed of nondimensional physical parameters. A set of basic equations for <span class="hlt">bubbly</span> flows is composed of the averaged equations of mass and momentum, the Keller equation for <span class="hlt">bubble</span> wall, and supplementary equations. As a result, two types of evolution equations, a nonlinear Schrödinger equation including dissipation, diffraction, and nonuniform effects for high-frequency short-wavelength case, and a Khokhlov-Zabolotskaya-Kuznetsov equation including dispersion and nonuniform effects for low-frequency long-wavelength case, are derived from the basic set.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950029712&hterms=bubbling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbubbling','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950029712&hterms=bubbling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbubbling"><span>Methane emission by <span class="hlt">bubbling</span> from Gatun Lake, Panama</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Keller, Michael; Stallard, Robert F.</p> <p>1994-01-01</p> <p>We studied methane emission by <span class="hlt">bubbling</span> from Gatun Lake, Panama, at water depths of less than 1 m to about 10 m. Gas <span class="hlt">bubbles</span> were collected in floating traps deployed during 12- to 60-hour observation periods. Comparison of floating traps and floating chambers showed that about 98% of methane emission occurred by <span class="hlt">bubbling</span> and only 2% occurred by diffusion. Average methane concentration of <span class="hlt">bubbles</span> at our sites varied from 67% to 77%. Methane emission by <span class="hlt">bubbling</span> occurred episodically, with greatest rates primarily between the hours of 0800 and 1400 LT. Events appear to be triggered by wind. The flux of methane associated with <span class="hlt">bubbling</span> was strongly anticorrelated with water depth. Seasonal changes in water depth caused seasonal variation of methane emission. <span class="hlt">Bubble</span> methane fluxes through the lake surface into the atmosphere measured during 24-hour intervals were least (10-200 mg/m2/d) at deeper sites (greater than 7 m) and greatest (300-2000 mg/m2/d) at shallow sites (less than 2 m).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AIPC.1474..155S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AIPC.1474..155S"><span>Orbital motions of <span class="hlt">bubbles</span> in an acoustic field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shirota, Minori; Yamashita, Ko; Inamura, Takao</p> <p>2012-09-01</p> <p>This experimental study aims to clarify the mechanism of orbital motion of two oscillating <span class="hlt">bubbles</span> in an acoustic field. Trajectory of the orbital motion on the wall of a spherical levitator was observed using a high-speed video camera. Because of a good repeatability in volume oscillation of <span class="hlt">bubbles</span>, we were also able to observe the radial motion driven at 24 kHz by stroboscopic like imaging technique. The orbital motions of <span class="hlt">bubbles</span> raging from 0.13 to 0.18 mm were examined with different forcing amplitude and in different viscous oils. As a result, we found that pairs of <span class="hlt">bubbles</span> revolve along an elliptic orbit around the center of mass of the <span class="hlt">bubbles</span>. We also found that the two <span class="hlt">bubbles</span> perform anti-phase radial oscillation. Although this radial oscillation should result in a repulsive secondary Bjerknes force, the <span class="hlt">bubbles</span> kept a constant separate distance of about 1 mm, which indicates the existence of centripetal primary Bjerknes force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15835064','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15835064"><span>Dual-frequency ultrasound for detecting and sizing <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Buckey, Jay C; Knaus, Darin A; Alvarenga, Donna L; Kenton, Marc A; Magari, Patrick J</p> <p>2005-01-01</p> <p>ISS construction and Mars exploration require extensive extravehicular activity (EVA), exposing crewmembers to increased decompression sickness risk. Improved <span class="hlt">bubble</span> detection technologies could help increase EVA efficiency and safety. Creare Inc. has developed a <span class="hlt">bubble</span> detection and sizing instrument using dual-frequency ultrasound. The device emits "pump" and "image" signals at two frequencies. The low-frequency pump signal causes an appropriately-sized <span class="hlt">bubble</span> to resonate. When the image frequency hits a resonating <span class="hlt">bubble</span>, mixing signals are returned at the sum and difference of the two frequencies. To test the feasibility of transcutaneous intravascular detection, intravascular <span class="hlt">bubbles</span> in anesthetized swine were produced using agitated saline and decompression stress. Ultrasonic transducers on the chest provided the two frequencies. Mixing signals were detected transthoracically in the right atrium using both methods. A histogram of estimated <span class="hlt">bubble</span> sizes could be constructed. <span class="hlt">Bubbles</span> can be detected and sized transthoracically in the right atrium using dual-frequency ultrasound. c2005 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24401119','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24401119"><span>The elasticity of soap <span class="hlt">bubbles</span> containing wormlike micelles.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sabadini, Edvaldo; Ungarato, Rafael F S; Miranda, Paulo B</p> <p>2014-01-28</p> <p>Slow-motion imaging of the rupture of soap <span class="hlt">bubbles</span> generally shows the edges of liquid films retracting at a constant speed (known as the Taylor-Culick velocity). Here we investigate soap <span class="hlt">bubbles</span> formed from simple solutions of a cationic surfactant (cetyltrimethylammonium bromide - CTAB) and sodium salicylate. The interaction of salicylate ions with CTAB leads to the formation of wormlike micelles (WLM), which yield a viscoelastic behavior to the liquid film of the <span class="hlt">bubble</span>. We demonstrate that these elastic <span class="hlt">bubbles</span> collapse at a velocity up to 30 times higher than the Taylor-Culick limit, which has never been surpassed. This is because during the <span class="hlt">bubble</span> inflation, the entangled WLM chains stretch, storing elastic energy. This extra energy is then released during the rupture of the <span class="hlt">bubble</span>, yielding an additional driving force for film retraction (besides surface tension). This new mechanism for the bursting of elastic <span class="hlt">bubbles</span> may have important implications to the breakup of viscoelastic sprays in industrial applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8325E..2FT','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8325E..2FT"><span>Measurement and reduction of micro-<span class="hlt">bubble</span> formation in high-viscosity fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tom, Glenn; Liu, Wei</p> <p>2012-03-01</p> <p>Gases at high drive pressure can initially dissolve into the fluids used in lithography and other critical processes during the fabrication of integrated circuits. In the low pressure portion of the dispense train, the dissolved gases can revert to <span class="hlt">bubbles</span>. These <span class="hlt">bubbles</span> can: 1. Affect the compressibility of the working fluid and change the flow <span class="hlt">characteristics</span> of the dispense heads which require frequent re-tuning of the coating tools. 2. Contribute to defect formation if the <span class="hlt">bubbles</span> are trapped on the surface of the wafer. Photosensitive Polyimides (PI) have high viscosities (1000 to 20,000 cP). Because of the high viscosity, high-powered, expensive pumps are needed to effectively remove the fluid from its container. Suction from the pump filling cycle easily causes cavitation, which can create flow rate variability, and micro-<span class="hlt">bubble</span> formation. It is a common practice to apply pressure to the PI resists to minimize cavitation in the pump. The trade-off to this practice is the entrainment (dissolution) of the drive gas into the resist and the risk of micro-<span class="hlt">bubbles</span> forming later in the dispense train. In the current study, ATMI measured the effects of two methods of pressure dispense from the container on the amount of gas entrained in a viscous fluid: (1) indirect pressure dispense and (2) direct pressure dispense. The main analytical method employed to measure the amount of dissolved gases is a gas chromatograph (GC), which can measure the concentration of gases dissolved in a volatile fluid. It is not suitable to measure gases in low volatility fluids. The new test method developed, however, is capable of measuring dissolved gases in low volatility fluids.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1426481-magnetic-skyrmion-bubble-motion-driven-surface-acoustic-waves','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1426481-magnetic-skyrmion-bubble-motion-driven-surface-acoustic-waves"><span>Magnetic skyrmion <span class="hlt">bubble</span> motion driven by surface acoustic waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Nepal, Rabindra; Güngördü, Utkan; Kovalev, Alexey A.</p> <p>2018-03-12</p> <p>Here, we study the dynamical control of a magnetic skyrmion <span class="hlt">bubble</span> by using counter-propagating surface acoustic waves (SAWs) in a ferromagnet. First, we determine the <span class="hlt">bubble</span> mass and derive the force due to SAWs acting on a magnetic <span class="hlt">bubble</span> using Thiele’s method. The force that pushes the <span class="hlt">bubble</span> is proportional to the strain gradient for the major strain component. We then study the dynamical pinning and motion of magnetic <span class="hlt">bubbles</span> by SAWs in a nanowire. In a disk geometry, we propose a SAWs-driven skyrmion <span class="hlt">bubble</span> oscillator with two resonant frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1426481-magnetic-skyrmion-bubble-motion-driven-surface-acoustic-waves','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1426481-magnetic-skyrmion-bubble-motion-driven-surface-acoustic-waves"><span>Magnetic skyrmion <span class="hlt">bubble</span> motion driven by surface acoustic waves</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Nepal, Rabindra; Güngördü, Utkan; Kovalev, Alexey A.</p> <p></p> <p>Here, we study the dynamical control of a magnetic skyrmion <span class="hlt">bubble</span> by using counter-propagating surface acoustic waves (SAWs) in a ferromagnet. First, we determine the <span class="hlt">bubble</span> mass and derive the force due to SAWs acting on a magnetic <span class="hlt">bubble</span> using Thiele’s method. The force that pushes the <span class="hlt">bubble</span> is proportional to the strain gradient for the major strain component. We then study the dynamical pinning and motion of magnetic <span class="hlt">bubbles</span> by SAWs in a nanowire. In a disk geometry, we propose a SAWs-driven skyrmion <span class="hlt">bubble</span> oscillator with two resonant frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820015548','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820015548"><span>Dielectrophoretic levitation of droplets and <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, T. B.</p> <p>1982-01-01</p> <p>Uncharged droplets and <span class="hlt">bubbles</span> can be levitated dielectrophoretically in liquids using strong, nonuniform electric fields. The general equations of motion for a droplet or <span class="hlt">bubble</span> in an axisymmetric, divergence-free electrostatic field allow determination of the conditions necessary and sufficient for stable levitation. The design of dielectrophoretic (DEP) levitation electrode structures is simplified by a Taylor-series expansion of cusped axisymmetric electrostatic fields. Extensive experimental measurements on <span class="hlt">bubbles</span> in insulating liquids verify the simple dielectrophoretic model. Other have extended dielectrophoretic levitation to very small particles in aqueous media. Applications of DEP levitation to the study of gas <span class="hlt">bubbles</span>, liquid droplets, and solid particles are discussed. Some of these applications are of special interest in the reduced gravitational field of a spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JFM...442..171P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JFM...442..171P"><span>Expansion of a compressible gas <span class="hlt">bubble</span> in Stokes flow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pozrikidis, C.</p> <p>2001-09-01</p> <p>The flow-induced deformation of an inviscid <span class="hlt">bubble</span> occupied by a compressible gas and suspended in an ambient viscous liquid is considered at low Reynolds numbers with particular reference to the pressure developing inside the <span class="hlt">bubble</span>. Ambient fluid motion alters the <span class="hlt">bubble</span> pressure with respect to that established in the quiescent state, and requires the <span class="hlt">bubble</span> to expand or contract according to an assumed equation of state. When changes in the <span class="hlt">bubble</span> volume are prohibited by a global constraint on the total volume of the flow, the ambient pressure is modified while the <span class="hlt">bubble</span> pressure remains constant during the deformation. A numerical method is developed for evaluating the pressure inside a two-dimensional <span class="hlt">bubble</span> in an ambient Stokes flow on the basis of the normal component of the interfacial force balance involving the capillary pressure, the normal viscous stress, and the pressure at the free surface on the side of the liquid; the last is computed by evaluating a strongly singular integral. Dynamical simulations of <span class="hlt">bubble</span> deformation are performed using the boundary integral method properly implemented to remove the multiplicity of solutions due to the a priori unknown rate of expansion, and three particular problems are discussed in detail: the shrinkage of a <span class="hlt">bubble</span> at a specified rate, the deformation of a <span class="hlt">bubble</span> subject to simple shear flow, and the deformation of a <span class="hlt">bubble</span> subject to a purely elongational flow. In the case of shrinkage, it is found that the surface tension plays a critical role in determining the behaviour of the <span class="hlt">bubble</span> pressure near the critical time when the <span class="hlt">bubble</span> disappears. In the case of shear or elongational flow, it is found that the <span class="hlt">bubble</span> contracts during an initial period of deformation from the circular shape, and then it expands to obtain a stationary shape whose area is higher than that assumed in the quiescent state. Expansion may destabilize the <span class="hlt">bubble</span> by raising the capillary number above the critical threshold under which</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27292094','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27292094"><span>How Stressful Is "Deep <span class="hlt">Bubbling</span>"?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tyrmi, Jaana; Laukkanen, Anne-Maria</p> <p>2017-03-01</p> <p>Water resistance therapy by phonating through a tube into the water is used to treat dysphonia. Deep submersion (≥10 cm in water, "deep <span class="hlt">bubbling</span>") is used for hypofunctional voice disorders. Using it with caution is recommended to avoid vocal overloading. This experimental study aimed to investigate how strenuous "deep <span class="hlt">bubbling</span>" is. Fourteen subjects, half of them with voice training, repeated the syllable [pa:] in comfortable speaking pitch and loudness, loudly, and in strained voice. Thereafter, they phonated a vowel-like sound both in comfortable loudness and loudly into a glass resonance tube immersed 10 cm into the water. Oral pressure, contact quotient (CQ, calculated from electroglottographic signal), and sound pressure level were studied. The peak oral pressure P(oral) during [p] and shuttering of the outer end of the tube was measured to estimate the subglottic pressure P(sub) and the mean P(oral) during vowel portions to enable calculation of transglottic pressure P(trans). Sensations during phonation were reported with an open-ended interview. P(sub) and P(oral) were higher in "deep <span class="hlt">bubbling</span>" and P(trans) lower than in loud syllable phonation, but the CQ did not differ significantly. Similar results were obtained for the comparison between loud "deep <span class="hlt">bubbling</span>" and strained phonation, although P(sub) did not differ significantly. Most of the subjects reported "deep <span class="hlt">bubbling</span>" to be stressful only for respiratory and lip muscles. No big differences were found between trained and untrained subjects. The CQ values suggest that "deep <span class="hlt">bubbling</span>" may increase vocal fold loading. Further studies should address impact stress during water resistance exercises. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034415','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034415"><span>Pressure waves in a supersaturated <span class="hlt">bubbly</span> magma</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kurzon, I.; Lyakhovsky, V.; Navon, O.; Chouet, B.</p> <p>2011-01-01</p> <p>We study the interaction of acoustic pressure waves with an expanding <span class="hlt">bubbly</span> magma. The expansion of magma is the result of <span class="hlt">bubble</span> growth during or following magma decompression and leads to two competing processes that affect pressure waves. On the one hand, growth in vesicularity leads to increased damping and decreased wave amplitudes, and on the other hand, a decrease in the effective bulk modulus of the <span class="hlt">bubbly</span> mixture reduces wave velocity, which in turn, reduces damping and may lead to wave amplification. The additional acoustic energy originates from the chemical energy released during <span class="hlt">bubble</span> growth. We examine this phenomenon analytically to identify conditions under which amplification of pressure waves is possible. These conditions are further examined numerically to shed light on the frequency and phase dependencies in relation to the interaction of waves and growing <span class="hlt">bubbles</span>. Amplification is possible at low frequencies and when the growth rate of <span class="hlt">bubbles</span> reaches an optimum value for which the wave velocity decreases sufficiently to overcome the increased damping of the vesicular material. We examine two amplification phase-dependent effects: (1) a tensile-phase effect in which the inserted wave adds to the process of <span class="hlt">bubble</span> growth, utilizing the energy associated with the gas overpressure in the <span class="hlt">bubble</span> and therefore converting a large proportion of this energy into additional acoustic energy, and (2) a compressive-phase effect in which the pressure wave works against the growing <span class="hlt">bubbles</span> and a large amount of its acoustic energy is dissipated during the first cycle, but later enough energy is gained to amplify the second cycle. These two effects provide additional new possible mechanisms for the amplification phase seen in Long-Period (LP) and Very-Long-Period (VLP) seismic signals originating in magma-filled cracks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApPhL.101g1602P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApPhL.101g1602P"><span>Role of entrapped vapor <span class="hlt">bubbles</span> during microdroplet evaporation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Putnam, Shawn A.; Byrd, Larry W.; Briones, Alejandro M.; Hanchak, Michael S.; Ervin, Jamie S.; Jones, John G.</p> <p>2012-08-01</p> <p>On superheated surfaces, the air <span class="hlt">bubble</span> trapped during impingement grows into a larger vapor <span class="hlt">bubble</span> and oscillates at the frequency predicted for thermally induced capillary waves. In some cases, the entrapped vapor <span class="hlt">bubble</span> penetrates the droplet interface, leaving a micron-sized coffee-ring pattern of pure fluid. Vapor <span class="hlt">bubble</span> entrapment, however, does not influence the evaporation rate. This is also true on laser heated surfaces, where a laser can thermally excite capillary waves and induce <span class="hlt">bubble</span> oscillations over a broad range of frequencies, suggesting that exciting perturbations in a pinned droplets interface is not an effective avenue for enhancing evaporative heat transfer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F8002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F8002G"><span><span class="hlt">Bubble</span> coalescence in a Newtonian fluid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garg, Vishrut; Basaran, Osman</p> <p>2017-11-01</p> <p><span class="hlt">Bubble</span> coalescence plays a central role in the hydrodynamics of gas-liquid systems such as <span class="hlt">bubble</span> column reactors, spargers, and foams. Two <span class="hlt">bubbles</span> approaching each other at velocity V coalesce when the thin film between them ruptures, which is often the rate-limiting step. Experimental studies of this system are difficult, and recent works provide conflicting results on the effect of V on coalescence times. We simulate the head-on approach of two <span class="hlt">bubbles</span> of equal radii R in an incompressible Newtonian fluid (density ρ, viscosity μ, and surface tension σ) by solving numerically the free boundary problem comprised of the Navier Stokes and continuity equations. Simulations are made challenging by the existence of highly disparate lengthscales, i.e. film thickness and drop radii, which are resolved by using the method of elliptic mesh generation. For a given liquid, the <span class="hlt">bubbles</span> are shown to coalesce for all velocities below a critical value. The effects of Ohnesorge number Oh = μ /√{ ρσR } on coalescence time and critical velocity are also investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986PhRvD..34.2913L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986PhRvD..34.2913L"><span>Inflation and <span class="hlt">bubbles</span> in general relativity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laguna-Castillo, Pablo; Matzner, Richard A.</p> <p>1986-11-01</p> <p>Following Israel's study of singular hypersurfaces and thin shells in general relativity, the complete set of Einstein's field equations in the presence of a <span class="hlt">bubble</span> boundary SIGMA is reviewed for all spherically symmetric embedding four-geometries M+/-. The mapping that identifies points between the boundaries Σ+ and Σ- is obtained explicitly when the regions M+ and M- are described by a de Sitter and a Minkowski metric, respectively. In addition, the evolution of a <span class="hlt">bubble</span> with vanishing surface energy density is studied in a spatially flat Robertson-Walker space-time, for region M- radiation dominated with a vanishing cosmological constant, and an energy equation in M+ determined by the matching. It is found that this type of <span class="hlt">bubble</span> leads to a ``worm-hole'' matching; that is, an infinite extent exterior of a sphere is joined across the wall to another infinite extent exterior of a sphere. Interior-interior matches are also possible. Under this model, solutions for a <span class="hlt">bubble</span> following a Hubble law are analyzed. Numerical solutions for <span class="hlt">bubbles</span> with constant tension are also obtained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.437.3626I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.437.3626I"><span>A radio characterization of Galactic compact <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ingallinera, A.; Trigilio, C.; Umana, G.; Leto, P.; Noriega-Crespo, A.; Flagey, N.; Paladini, R.; Agliozzo, C.; Buemi, C. S.</p> <p>2014-02-01</p> <p>We report the radio observations of a subsample of the 428 Galactic compact <span class="hlt">bubbles</span> discovered at 24 μm with the MIPSGAL survey. Pervasive through the entire Galactic plane, these objects are thought to be different kinds of evolved stars. The very large majority of the <span class="hlt">bubbles</span> (˜70 per cent) are however not yet classified. We conducted radio observations with the Expanded Very Large Array at 6 and 20 cm in order to obtain the spectral index of 55 <span class="hlt">bubbles</span>. We found that at least 70 per cent of the 31 <span class="hlt">bubbles</span> for which we were effectively able to compute the spectral index (or its lower limit) are likely to be thermal emitters. We were also able to resolve some <span class="hlt">bubbles</span>, obtaining that the size of the radio nebula is usually similar to the IR size, although our low resolution (with respect to IR images) did not allow further morphological studies. Comparisons between radio flux densities and IR archive data from Spitzer and IRAS suggest that at least three unclassified <span class="hlt">bubbles</span> can be treated as planetary nebula candidates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ChOE...32...26Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ChOE...32...26Y"><span>Far-Field Noise Induced by <span class="hlt">Bubble</span> near Free Surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Xi; Li, Jiang-tao; Liu, Jian-hua; Chen, Hai-long</p> <p>2018-03-01</p> <p>The motion of a <span class="hlt">bubble</span> near the free surface is solved by the boundary element method based on the linear wave equation, and the influence of fluid compressibility on <span class="hlt">bubble</span> dynamics is analyzed. Based on the solution of the <span class="hlt">bubble</span> motion, the far-field radiation noise induced by the <span class="hlt">bubble</span> is calculated using Kirchhoff moving boundary integral equation, and the influence of free surface on far-field noise is researched. As the results, the oscillation amplitude of the <span class="hlt">bubble</span> is weakened in compressible fluid compared with that in incompressible fluid, and the free surface amplifies the effect of fluid compressibility. When the distance between the <span class="hlt">bubble</span> and an observer is much larger than that between the <span class="hlt">bubble</span> and free surface, the sharp wave trough of the sound pressure at the observer occurs. With the increment of the distance between the <span class="hlt">bubble</span> and free surface, the time of the wave trough appearing is delayed and the value of the wave trough increase. When the distance between the observer and the <span class="hlt">bubble</span> is reduced, the sharp wave trough at the observer disappears.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhL.106d3101N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhL.106d3101N"><span>Photothermally controlled Marangoni flow around a micro <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Namura, Kyoko; Nakajima, Kaoru; Kimura, Kenji; Suzuki, Motofumi</p> <p>2015-01-01</p> <p>We have experimentally investigated the control of Marangoni flow around a micro <span class="hlt">bubble</span> using photothermal conversion. Using a focused laser spot acting as a highly localized heat source on Au nanoparticles/dielectric/Ag mirror thin film enables us to create a micro <span class="hlt">bubble</span> and to control the temperature gradient around the <span class="hlt">bubble</span> at a micrometer scale. When we irradiate the laser next to the <span class="hlt">bubble</span>, a strong main flow towards the <span class="hlt">bubble</span> and two symmetric rotation flows on either side of it develop. The shape of this rotation flow shows a significant transformation depending on the relative position of the <span class="hlt">bubble</span> and the laser spot. Using this controllable rotation flow, we have demonstrated sorting of the polystyrene spheres with diameters of 2 μm and 0.75 μm according to their size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/10116967','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/10116967"><span><span class="hlt">Bubble</span> fusion: Preliminary estimates</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Krakowski, R.A.</p> <p>1995-02-01</p> <p>The collapse of a gas-filled <span class="hlt">bubble</span> in disequilibrium (i.e., internal pressure {much_lt} external pressure) can occur with a significant focusing of energy onto the entrapped gas in the form of pressure-volume work and/or acoustical shocks; the resulting heating can be sufficient to cause ionization and the emission of atomic radiations. The suggestion that extreme conditions necessary for thermonuclear fusion to occur may be possible has been examined parametrically in terms of the ratio of initial <span class="hlt">bubble</span> pressure relative to that required for equilibrium. In this sense, the disequilibrium <span class="hlt">bubble</span> is viewed as a three-dimensional ``sling shot`` that is ``loaded`` tomore » an extent allowed by the maximum level of disequilibrium that can stably be achieved. Values of this disequilibrium ratio in the range 10{sup {minus}5}--10{sup {minus}6} are predicted by an idealized <span class="hlt">bubble</span>-dynamics model as necessary to achieve conditions where nuclear fusion of deuterium-tritium might be observed. Harmonic and aharmonic pressurizations/decompressions are examined as means to achieve the required levels of disequilibrium required to create fusion conditions. A number of phenomena not included in the analysis reported herein could enhance or reduce the small levels of nuclear fusions predicted.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F8003P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F8003P"><span>The collapse of a cavitation <span class="hlt">bubble</span> in a corner</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peters, Ivo; Tagawa, Yoshiyuki</p> <p>2017-11-01</p> <p>The collapse of cavitation <span class="hlt">bubbles</span> is influenced by the surrounding geometry. A classic example is the collapse of a <span class="hlt">bubble</span> near a solid wall, where a fast jet is created towards the wall. The addition of a second wall creates a non-axisymmetric flow field, which influences the displacement and jet formation during the collapse of a <span class="hlt">bubble</span>. In this experimental study we generate mm-sized vapor <span class="hlt">bubbles</span> using a focused pulsed laser, giving us full control over the position of the <span class="hlt">bubble</span>. The corner geometry is formed by two glass slides. High-speed imaging reveals the directional motion of the <span class="hlt">bubble</span> during the collapse. We find that the <span class="hlt">bubble</span> displacement cannot be fully described by a simple superposition of the <span class="hlt">bubble</span> dynamics of the two walls individually. Comparison of our experimental results to a model based on potential flow shows a good agreement for the direction of displacement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PhRvD..76l3512G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PhRvD..76l3512G"><span>Eternal inflation, <span class="hlt">bubble</span> collisions, and the persistence of memory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garriga, Jaume; Guth, Alan H.; Vilenkin, Alexander</p> <p>2007-12-01</p> <p>A “<span class="hlt">bubble</span> universe” nucleating in an eternally inflating false vacuum will experience, in the course of its expansion, collisions with an infinite number of other <span class="hlt">bubbles</span>. In an idealized model, we calculate the rate of collisions around an observer inside a given reference <span class="hlt">bubble</span>. We show that the collision rate violates both the homogeneity and the isotropy of the <span class="hlt">bubble</span> universe. Each <span class="hlt">bubble</span> has a center which can be related to “the beginning of inflation” in the parent false vacuum, and any observer not at the center will see an anisotropic <span class="hlt">bubble</span> collision rate that peaks in the outward direction. Surprisingly, this memory of the onset of inflation persists no matter how much time elapses before the nucleation of the reference <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820031637&hterms=SODA-LIME-SILICA+GLASS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DSODA-LIME-SILICA%2BGLASS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820031637&hterms=SODA-LIME-SILICA+GLASS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DSODA-LIME-SILICA%2BGLASS"><span>Behavior of <span class="hlt">bubbles</span> in glassmelts. II - Dissolution of a stationary <span class="hlt">bubble</span> containing a diffusing and a nondiffusing gas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weinberg, M. C.; Onorato, P. I. K.; Uhlmann, D. R.</p> <p>1980-01-01</p> <p>The effect of a foreign nondiffusing gas on the rate of shrinkage of an oxygen <span class="hlt">bubble</span> in a soda-lime-silica melt was studied. The rate of change of <span class="hlt">bubble</span> radius with time was computed using the quasi-stationary approximation. The effects of melt undersaturation and initial fraction of foreign gas in the <span class="hlt">bubble</span> are considered and compared with those calculated using previously derived expressions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950071305&hterms=basil&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dbasil','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950071305&hterms=basil&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dbasil"><span><span class="hlt">Bubble</span>-Free Containers For Liquids In Microgravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kornfeld, Dale M.; Antar, Basil L.</p> <p>1995-01-01</p> <p>Reports discuss entrainment of gas <span class="hlt">bubbles</span> during handling of liquids in microgravity, and one report proposes containers filled with liquids in microgravity without entraining <span class="hlt">bubbles</span>. <span class="hlt">Bubbles</span> are troublesome in low-gravity experiments - particularly in biological experiments. Wire-mesh cage retains liquid contents without solid wall, because in microgravity, surface tension of liquid exerts sufficient confining force.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51D2092D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51D2092D"><span>Influences of Scavenging and Removal of Surfactants by <span class="hlt">Bubble</span> Processing on Primary Marine Aerosol Production from North Atlantic Seawater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duplessis, P.; Chang, R.; Frossard, A. A.; Keene, W. C.; Maben, J. R.; Long, M. S.; Beaupre, S. R.; Kieber, D. J.; Kinsey, J. D.; Zhu, Y.; Lu, X.; Bisgrove, J.</p> <p>2017-12-01</p> <p>Primary marine aerosol particles (PMA) are produced by bursting <span class="hlt">bubbles</span> from breaking waves at the air-sea interface and significantly modulate atmospheric chemical transformations and cloud properties. Surfactants in bulk seawater rapidly (seconds) adsorb onto fresh <span class="hlt">bubble</span> surfaces forming organic films that influence size, <span class="hlt">rise</span> velocity, bursting behavior, and associated PMA emissions. During a cruise on the R/V Endeavor in September and October 2016, PMA production from biologically productive and oligotrophic seawater was investigated at four stations in the western North Atlantic Ocean. PMA were produced in a high-capacity generator via turbulent mixing of seawater and clean air in a Venturi nozzle. When the flow of fresh seawater through the generator was turned off, surfactant depletion via <span class="hlt">bubble</span> processing resulted in greater PMA mass production efficiencies per unit air detrained but had no consistent influence on number production efficiencies. The greater (factor of 3) production efficiencies of organic matter associated with PMA generated with the Venturi relative to those generated with frits during previous campaigns contributed to a faster depletion of surfactants from the seawater reservoir and corresponding divergence in response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17895417','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17895417"><span>Use of a "small-<span class="hlt">bubble</span> technique" to increase the success of Anwar's "big-<span class="hlt">bubble</span> technique" for deep lamellar keratoplasty with complete baring of Descemet's membrane.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Parthasarathy, Anand; Por, Yong Ming; Tan, Donald T H</p> <p>2007-10-01</p> <p>To describe a quick and simple "small-<span class="hlt">bubble</span>" technique to immediately determine the success of attaining complete Descemet's membrane (DM) separation from corneal stroma through Anwar's "big-<span class="hlt">bubble</span>" technique of deep anterior lamellar keratoplasty (DALK) for complete stromal removal. A partial trephination was followed by a lamellar dissection of the anterior stroma. Deep stromal air injection was then attempted to achieve the big <span class="hlt">bubble</span> to help separate the stroma from the DM. To confirm that a big <span class="hlt">bubble</span> had been achieved, a small air <span class="hlt">bubble</span> was injected into the anterior chamber (AC) through a limbal paracentesis. If the small <span class="hlt">bubble</span> is then seen at the corneal periphery, it confirms that the big-<span class="hlt">bubble</span> separation of DM was successful because the convex nature of the <span class="hlt">bubble</span> will cause it to protrude posteriorly, forcing the small AC <span class="hlt">bubble</span> to the periphery. If the small AC <span class="hlt">bubble</span> is not seen in the corneal periphery, this means that it is present in the centre, beneath the opaque corneal stroma, and therefore the big <span class="hlt">bubble</span> has not been achieved. We used the small-<span class="hlt">bubble</span> technique to confirm the presence of the big <span class="hlt">bubble</span> in three (one keratoconus, one interstitial keratitis and one dense corneal scar) out of 41 patients who underwent DALK. The small-<span class="hlt">bubble</span> technique confirmed that the big <span class="hlt">bubble</span> was achieved in the eye of all three patients. Complete stromal removal with baring of the DM was achieved, and postoperatively all three eyes achieved best corrected vision of 6/6. The small-<span class="hlt">bubble</span> technique can be a useful surgical tool for corneal surgeons attempting lamellar keratoplasty using the big-<span class="hlt">bubble</span> technique. It helps in confirming the separation of DM from the deep stroma, which is important in achieving total stromal replacement. It will help to make the transition to lamellar keratoplasty smoother, enhance corneal graft success and improve visual outcomes in patients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160001341','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160001341"><span>Capillary Channel Flow (CCF) EU2-02 on the International Space Station (ISS): An Experimental Investigation of Passive <span class="hlt">Bubble</span> Separations in an Open Capillary Channel</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weislogel, Mark M.; Wollman, Andrew P.; Jenson, Ryan M.; Geile, John T.; Tucker, John F.; Wiles, Brentley M.; Trattner, Andy L.; DeVoe, Claire; Sharp, Lauren M.; Canfield, Peter J.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20160001341'); toggleEditAbsImage('author_20160001341_show'); toggleEditAbsImage('author_20160001341_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20160001341_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20160001341_hide"></p> <p>2015-01-01</p> <p>It would be signicantly easier to design fluid systems for spacecraft if the fluid phases behaved similarly to those on earth. In this research an open 15:8 degree wedge-sectioned channel is employed to separate <span class="hlt">bubbles</span> from a two-phase flow in a microgravity environment. The <span class="hlt">bubbles</span> appear to <span class="hlt">rise</span> in the channel and coalesce with the free surface in much the same way as would <span class="hlt">bubbles</span> in a terrestrial environment, only the combined effects of surface tension, wetting, and conduit geometry replace the role of buoyancy. The host liquid is drawn along the channel by a pump and noncondensible gas <span class="hlt">bubbles</span> are injected into it near the channel vertex at the channel inlet. Control parameters include <span class="hlt">bubble</span> volume, <span class="hlt">bubble</span> frequency, liquid volumetric flow rate, and channel length. The asymmetrically confined <span class="hlt">bubbles</span> are driven in the cross-flow direction by capillary forces until they at least become inscribed within the section or until they come in contact with the free surface, whereupon they usually coalesce and leave the flow. The merging of <span class="hlt">bubbles</span> enhances, but does not guarantee, the latter. The experiments are performed aboard the International Space Station as a subset of the Capillary Channel Flow experiments. The flight hardware is commanded remotely and continuously from ground stations during the tests and an extensive array of experiments is conducted identifying numerous <span class="hlt">bubble</span> flow regimes and regime transitions depending on the ratio and magnitude of the gas and liquid volumetric flow rates. The breadth of the publicly available experiments is conveyed herein primarily by narrative and by regime maps, where transitions are approximated by simple expressions immediately useful for the purposes of design and deeper analysis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15246416','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15246416"><span>Void fraction and velocity measurement of simulated <span class="hlt">bubble</span> in a rotating disc using high frame rate neutron radiography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saito, Y; Mishima, K; Matsubayashi, M</p> <p>2004-10-01</p> <p>To evaluate measurement error of local void fraction and velocity field in a gas-molten metal two-phase flow by high-frame-rate neutron radiography, experiments using a rotating stainless-steel disc, which has several holes of various diameters and depths simulating gas <span class="hlt">bubbles</span>, were performed. Measured instantaneous void fraction and velocity field of the simulated <span class="hlt">bubbles</span> were compared with the calculated values based on the rotating speed, the diameter and the depth of the holes as parameters and the measurement error was evaluated. The rotating speed was varied from 0 to 350 rpm (tangential velocity of the simulated <span class="hlt">bubbles</span> from 0 to 1.5 m/s). The effect of shutter speed of the imaging system on the measurement error was also investigated. It was revealed from the Lagrangian time-averaged void fraction profile that the measurement error of the instantaneous void fraction depends mainly on the light-decay <span class="hlt">characteristics</span> of the fluorescent converter. The measurement error of the instantaneous local void fraction of simulated <span class="hlt">bubbles</span> is estimated to be 20%. In the present imaging system, the light-decay <span class="hlt">characteristics</span> of the fluorescent converter affect the measurement remarkably, and so should be taken into account in estimating the measurement error of the local void fraction profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27779873','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27779873"><span>An Analysis of <span class="hlt">Bubble</span> Deformation by a Sphere Relevant to the Measurements of <span class="hlt">Bubble</span>-Particle Contact Interaction and Detachment Forces.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sherman, H; Nguyen, A V; Bruckard, W</p> <p>2016-11-22</p> <p>Atomic force microscopy makes it possible to measure the interacting forces between individual colloidal particles and air <span class="hlt">bubbles</span>, which can provide a measure of the particle hydrophobicity. To indicate the level of hydrophobicity of the particle, the contact angle can be calculated, assuming that no interfacial deformation occurs with the <span class="hlt">bubble</span> retaining a spherical profile. Our experimental results obtained using a modified sphere tensiometry apparatus to detach submillimeter spherical particles show that deformation of the <span class="hlt">bubble</span> interface does occur during particle detachment. We also develop a theoretical model to describe the equilibrium shape of the <span class="hlt">bubble</span> meniscus at any given particle position, based on the minimization of the free energy of the system. The developed model allows us to analyze high-speed video captured during detachment. In the system model deformation of the <span class="hlt">bubble</span> profile is accounted for by the incorporation of a Lagrange multiplier into both the Young-Laplace equation and the force balance. The solution of the <span class="hlt">bubble</span> profile matched to the high-speed video allows us to accurately calculate the contact angle and determine the total force balance as a function of the contact point of the <span class="hlt">bubble</span> on the particle surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhRvF...2j4303O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhRvF...2j4303O"><span>Visualization of the wake behind a sliding <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Reilly Meehan, R.; Grennan, K.; Davis, I.; Nolan, K.; Murray, D. B.</p> <p>2017-10-01</p> <p>In this work, Schlieren measurements are presented for the wake of an air <span class="hlt">bubble</span> sliding under a heated, inclined surface in quiescent water to provide new insights into the intricate sliding <span class="hlt">bubble</span> wake structure and the associated convective cooling process. This is a two-phase flow configuration that is pertinent to thermal management solutions, where the fundamental flow physics have yet to be fully described. In this work, we present an experimental apparatus that enables high-quality Schlieren images for different <span class="hlt">bubble</span> sizes and measurement planes. By combining these visualizations with an advanced <span class="hlt">bubble</span> tracking technique, we can simultaneously quantify the symbiotic relationship that exists between the sliding <span class="hlt">bubble</span> dynamics and its associated wake. An unstable, dynamic wake structure is revealed, consisting of multiple hairpin-shaped vortex structures interacting within the macroscopic area affected by the <span class="hlt">bubble</span>. As vorticity is generated in the near wake, the <span class="hlt">bubble</span> shape is observed to recoil and rebound. This also occurs normal to the surface and is particularly noticeable for larger <span class="hlt">bubble</span> sizes, with a periodic ejection of material from the near wake corresponding to significant shape changes. These findings, along with their implications from a thermal management perspective, provide information on the rich dynamics of this natural flow that cannot be obtained using alternate experimental techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA12A..08V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA12A..08V"><span>C/NOFS, SWARM, and LISN Observations of Equatorial Plasma <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valladares, C. E.; Coisson, P.; Buchert, S. C.; Huang, C.; Sheehan, R.</p> <p>2017-12-01</p> <p>We have used Langmuir Probe densities measured during the early commissioning phase of the SWARM mission and simultaneous number densities recorded with the PLP instrument on board the C/NOFS satellite to investigate the geometric <span class="hlt">characteristics</span> of equatorial plasma <span class="hlt">bubbles</span> (EPB). The SWARM satellites orbit in a polar orbit and the C/NOFS satellite has a near equatorial trajectory making it possible to precisely measure the north-south and the east-west width of plasma depletions. This unique satellite database is complemented with TEC values collected with hundreds of GPS receivers that belong to LISN and other networks that operate in South and Central America. The GPS receivers provide multiple and almost concurrent observations of the TEC depletions that are required to calculate the velocity of plasma <span class="hlt">bubbles</span> as a function of time, latitude, and longitude. The <span class="hlt">bubble</span> velocity field commonly decreases through the night from 150 to 0 m/s and from low to higher latitudes at a rate equal to 5 m/s/degree. This <span class="hlt">bubble</span> velocity field is used to trace backward and forward in time the satellite and GPS observations and reconstruct plasma depletions in 3 dimensions. The 3-D geometry indicates that in December 2013, the EPBs most of the time correspond to a series of embedded shells that drift eastward with velocities that vary between 125 and 20 m/s. The 3-D reconstructed EPBs can be used to perform close comparisons with results of numerical simulations and 2-D observations conducted with coherent radars or imagers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JCAP...03..030W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JCAP...03..030W"><span>Simulating the universe(s): from cosmic <span class="hlt">bubble</span> collisions to cosmological observables with numerical relativity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wainwright, Carroll L.; Johnson, Matthew C.; Peiris, Hiranya V.; Aguirre, Anthony; Lehner, Luis; Liebling, Steven L.</p> <p>2014-03-01</p> <p>The theory of eternal inflation in an inflaton potential with multiple vacua predicts that our universe is one of many <span class="hlt">bubble</span> universes nucleating and growing inside an ever-expanding false vacuum. The collision of our <span class="hlt">bubble</span> with another could provide an important observational signature to test this scenario. We develop and implement an algorithm for accurately computing the cosmological observables arising from <span class="hlt">bubble</span> collisions directly from the Lagrangian of a single scalar field. We first simulate the collision spacetime by solving Einstein's equations, starting from nucleation and ending at reheating. Taking advantage of the collision's hyperbolic symmetry, the simulations are performed with a 1+1-dimensional fully relativistic code that uses adaptive mesh refinement. We then calculate the comoving curvature perturbation in an open Friedmann-Robertson-Walker universe, which is used to determine the temperature anisotropies of the cosmic microwave background radiation. For a fiducial Lagrangian, the anisotropies are well described by a power law in the cosine of the angular distance from the center of the collision signature. For a given form of the Lagrangian, the resulting observational predictions are inherently statistical due to stochastic elements of the <span class="hlt">bubble</span> nucleation process. Further uncertainties arise due to our imperfect knowledge about inflationary and pre-recombination physics. We characterize observational predictions by computing the probability distributions over four phenomenological parameters which capture these intrinsic and model uncertainties. This represents the first fully-relativistic set of predictions from an ensemble of scalar field models giving <span class="hlt">rise</span> to eternal inflation, yielding significant differences from previous non-relativistic approximations. Thus, our results provide a basis for a rigorous confrontation of these theories with cosmological data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPhCS.498a2001W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPhCS.498a2001W"><span>Can airborne ultrasound monitor <span class="hlt">bubble</span> size in chocolate?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watson, N.; Hazlehurst, T.; Povey, M.; Vieira, J.; Sundara, R.; Sandoz, J.-P.</p> <p>2014-04-01</p> <p>Aerated chocolate products consist of solid chocolate with the inclusion of <span class="hlt">bubbles</span> and are a popular consumer product in many countries. The volume fraction and size distribution of the <span class="hlt">bubbles</span> has an effect on their sensory properties and manufacturing cost. For these reasons it is important to have an online real time process monitoring system capable of measuring their <span class="hlt">bubble</span> size distribution. As these products are eaten by consumers it is desirable that the monitoring system is non contact to avoid food contaminations. In this work we assess the feasibility of using an airborne ultrasound system to monitor the <span class="hlt">bubble</span> size distribution in aerated chocolate bars. The experimental results from the airborne acoustic experiments were compared with theoretical results for known <span class="hlt">bubble</span> size distributions using COMSOL Multiphysics. This combined experimental and theoretical approach is used to develop a greater understanding of how ultrasound propagates through aerated chocolate and to assess the feasibility of using airborne ultrasound to monitor <span class="hlt">bubble</span> size distribution in these systems. The results indicated that a smaller <span class="hlt">bubble</span> size distribution would result in an increase in attenuation through the product.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.F8009S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.F8009S"><span>Shock waves from non-spherically collapsing cavitation <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Supponen, Outi; Obreschkow, Danail; Farhat, Mohamed</p> <p>2017-11-01</p> <p>Combining simultaneous high-speed imaging and hydrophone measurements, we uncover details of the multiple shock wave emission from laser-induced cavitation <span class="hlt">bubbles</span> collapsing in a non-spherical way. For strongly deformed <span class="hlt">bubbles</span> collapsing near a free surface, we identify the distinct shock waves caused by the jet impact onto the opposite <span class="hlt">bubble</span> wall and by the individual collapses of the remaining <span class="hlt">bubble</span> segments. The energy carried by each of these shocks depends on the level of <span class="hlt">bubble</span> deformation, quantified by the anisotropy parameter ζ, the dimensionless equivalent of the Kelvin impulse. For jetting <span class="hlt">bubbles</span>, at ζ < 0.01 , the jet impact hammer pressure is found to be the most energetic shock. Through statistical analysis of the experimental data and theoretical derivations, and by comparing <span class="hlt">bubbles</span> deformed by different sources (variable gravity achieved on parabolic flights, and neighboring free and rigid surfaces), we find that the shock peak pressure may be approximated as the jet impact-induced water hammer as ph = 0.45 (ρc2 Δp) 1 / 2ζ-1 .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AIPC.1022..460P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AIPC.1022..460P"><span><span class="hlt">Bubble</span> Proliferation in Shock Wave Lithotripsy Occurs during Inertial Collapse</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pishchalnikov, Yuri A.; McAteer, James A.; Pishchalnikova, Irina V.; Williams, James C.; Bailey, Michael R.; Sapozhnikov, Oleg A.</p> <p>2008-06-01</p> <p>In shock wave lithotripsy (SWL), firing shock pulses at slow pulse repetition frequency (0.5 Hz) is more effective at breaking kidney stones than firing shock waves (SWs) at fast rate (2 Hz). Since at fast rate the number of cavitation <span class="hlt">bubbles</span> increases, it appears that <span class="hlt">bubble</span> proliferation reduces the efficiency of SWL. The goal of this work was to determine the basis for <span class="hlt">bubble</span> proliferation when SWs are delivered at fast rate. <span class="hlt">Bubbles</span> were studied using a high-speed camera (Imacon 200). Experiments were conducted in a test tank filled with nondegassed tap water at room temperature. Acoustic pulses were generated with an electromagnetic lithotripter (DoLi-50). In the focus of the lithotripter the pulses consisted of a ˜60 MPa positive-pressure spike followed by up to -8 MPa negative-pressure tail, all with a total duration of about 7 μs. Nonlinear propagation steepened the shock front of the pulses to become sufficiently thin (˜0.03 μm) to impose differential pressure across even microscopic <span class="hlt">bubbles</span>. High-speed camera movies showed that the SWs forced preexisting microbubbles to collapse, jet, and break up into daughter <span class="hlt">bubbles</span>, which then grew rapidly under the negative-pressure phase of the pulse, but later coalesced to re-form a single <span class="hlt">bubble</span>. Subsequent <span class="hlt">bubble</span> growth was followed by inertial collapse and, usually, rebound. Most, if not all, cavitation <span class="hlt">bubbles</span> emitted micro-jets during their first inertial collapse and re-growth. After jetting, these rebounding <span class="hlt">bubbles</span> could regain a spherical shape before undergoing a second inertial collapse. However, either upon this second inertial collapse, or sometimes upon the first inertial collapse, the rebounding <span class="hlt">bubble</span> emerged from the collapse as a cloud of smaller <span class="hlt">bubbles</span> rather than a single <span class="hlt">bubble</span>. These daughter <span class="hlt">bubbles</span> could continue to rebound and collapse for a few cycles, but did not coalesce. These observations show that the positive-pressure phase of SWs fragments preexisting <span class="hlt">bubbles</span> but this initial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=SOAP&pg=7&id=EJ538246','ERIC'); return false;" href="https://eric.ed.gov/?q=SOAP&pg=7&id=EJ538246"><span>Colorful Demos with a Long-Lasting Soap <span class="hlt">Bubble</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Behroozi, F.; Olson, D. W.</p> <p>1994-01-01</p> <p>Describes several demonstrations that feature interaction of light with soap <span class="hlt">bubbles</span>. Includes directions about how to produce a long-lasting stationary soap <span class="hlt">bubble</span> with an easily changeable size and describes the interaction of white light with the <span class="hlt">bubble</span>. (DDR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70176133','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70176133"><span>Dynamics of diffusive <span class="hlt">bubble</span> growth and pressure recovery in a <span class="hlt">bubbly</span> rhyolitic melt embedded in an elastic solid</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chouet, Bernard A.; Dawson, Phillip B.; Nakano, Masaru</p> <p>2006-01-01</p> <p>We present a model of gas exsolution and <span class="hlt">bubble</span> expansion in a melt supersaturated in response to a sudden pressure drop. In our model, the melt contains a suspension of gas <span class="hlt">bubbles</span> of identical sizes and is encased in a penny-shaped crack embedded in an elastic solid. The suspension is modeled as a three-dimensional lattice of spherical cells with slight overlap, where each elementary cell consists of a gas <span class="hlt">bubble</span> surrounded by a shell of volatile-rich melt. The melt is then subjected to a step drop in pressure, which induces gas exsolution and <span class="hlt">bubble</span> expansion, resulting in the compression of the melt and volumetric expansion of the crack. The dynamics of diffusion-driven <span class="hlt">bubble</span> growth and volumetric crack expansion span 9 decades in time. The model demonstrates that the speed of the crack response depends strongly on volatile diffusivity in the melt and <span class="hlt">bubble</span> number density and is markedly sensitive to the ratio of crack thickness to crack radius and initial <span class="hlt">bubble</span> radius but is relatively insensitive to melt viscosity. The net drop in gas concentration in the melt after pressure recovery represents only a small fraction of the initial concentration prior to the drop, suggesting the melt may undergo numerous pressure transients before becoming significantly depleted of gases. The magnitude of pressure and volume recovery in the crack depends sensitively on the size of the input-pressure transient, becoming relatively larger for smaller-size transients in a melt containing <span class="hlt">bubbles</span> with initial radii less than 10-5 m. Amplification of the input transient may be large enough to disrupt the crack wall and induce brittle failure in the rock matrix surrounding the crack. Our results provide additional basis for the interpretation of volume changes in the magma conduit under Popocatépetl Volcano during Vulcanian degassing bursts in its eruptive activity in April–May 2000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JNuM..496..265W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JNuM..496..265W"><span>Helium <span class="hlt">bubbles</span> aggravated defects production in self-irradiated copper</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, FengChao; Zhu, YinBo; Wu, Qiang; Li, XinZhu; Wang, Pei; Wu, HengAn</p> <p>2017-12-01</p> <p>Under the environment of high radiation, materials used in fission and fusion reactors will internally accumulate numerous lattice defects and <span class="hlt">bubbles</span>. With extensive studies focused on <span class="hlt">bubble</span> resolution under irradiation, the mutually effects between helium <span class="hlt">bubbles</span> and displacement cascades in irradiated materials remain unaddressed. Therefore, the defects production and microstructure evolution under self-irradiation events in vicinity of helium <span class="hlt">bubbles</span> are investigated by preforming large scale molecular dynamics simulations in single-crystal copper. When subjected to displacement cascades, distinguished <span class="hlt">bubble</span> resolution categories dependent on <span class="hlt">bubble</span> size are observed. With the existence of <span class="hlt">bubbles</span>, radiation damage is aggravated with the increasing <span class="hlt">bubble</span> size, represented as the promotion of point defects and dislocations. The atomic mechanisms of heterogeneous dislocation structures are attributed to different helium-vacancy cluster modes, transforming from the resolved gas trapped with vacancies to the biased absorption of vacancies by the over-pressured <span class="hlt">bubble</span>. In both cases, helium impedes the recombination of point defects, leading to the accelerated formation of interstitial loops. The results and insight obtained here might contribute to understand the underlying mechanism of transmutant solute on the long-term evolution of irradiated materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70011271','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70011271"><span>Expendable <span class="hlt">bubble</span> tiltmeter for geophysical monitoring</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Westphal, J.A.; Carr, M.A.; Miller, W.F.; Dzurisin, D.</p> <p>1983-01-01</p> <p>An unusually rugged highly sensitive and inexpensive <span class="hlt">bubble</span> tiltmeter has been designed, tested, and built in quantity. These tiltmeters are presently used on two volcanoes and an Alaskan glacier, where they continuously monitor surface tilts of geological interest. This paper discusses the mechanical, thermal, and electric details of the meter, and illustrates its performance <span class="hlt">characteristics</span> in both large (>10-4 radian) and small (<10-6 radian) tilt environments. The meter's ultimate sensitivity is better than 2??10-8 radians rms for short periods (hours), and its useful dynamic range is greater than 10 4. Included is a short description of field use of the instrument for volcano monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDD27004T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDD27004T"><span>Repeated <span class="hlt">bubble</span> breakup and coalescence in perturbed Hele-Shaw channels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, Alice; Franco-Gomez, Andres; Hazel, Andrew; Juel, Anne</p> <p>2017-11-01</p> <p>The introduction of an axially-uniform, centred constriction in a Hele-Shaw channel leads to multiple propagation modes for both air fingers and <span class="hlt">bubbles</span>, including symmetric and asymmetric steadily propagating modes along with oscillations. These multiple modes correspond to a non-trivial bifurcation structure, and relate to the plethora of steadily propagating <span class="hlt">bubbles</span> and fingers which exist in the Saffman-Taylor system. In both experiments and depth-averaged computations, a very small centred occlusion can be enough to trigger <span class="hlt">bubble</span> breakup, with a single large centred <span class="hlt">bubble</span> splitting into two smaller <span class="hlt">bubbles</span> which propagate along each side of the channel. We present numerical simulations for the depth-averaged model, implementing geometric criteria for pinchoff and coalescence in order to track the <span class="hlt">bubble</span> before and beyond breakup. We find that the two-<span class="hlt">bubble</span> state is itself unstable, with finger competition causing one <span class="hlt">bubble</span> to move ahead; the trailing <span class="hlt">bubble</span> then moves across the channel to merge with the leading <span class="hlt">bubble</span>. However, the story is not always so simple, enabling complicated cascades of splitting and merging <span class="hlt">bubbles</span>. We compare the general dynamical behaviour, basins of attraction, and the details of merging and splitting, to experimental observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.656a2029M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.656a2029M"><span>Beer tapping: dynamics of <span class="hlt">bubbles</span> after impact</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mantič-Lugo, V.; Cayron, A.; Brun, P.-T.; Gallaire, F.</p> <p>2015-12-01</p> <p>Beer tapping is a well known prank where a bottle of beer is impacted from the top by a solid object, usually another bottle, leading to a sudden foam overflow. A description of the shock-driven <span class="hlt">bubble</span> dynamics leading to foaming is presented based on an experimental and numerical study evoking the following physical picture. First, the solid impact produces a sudden downwards acceleration of the bottle creating a strong depression in the liquid bulk. The existing <span class="hlt">bubbles</span> undergo a strong expansion and a sudden contraction ending in their collapse and fragmentation into a large amount of small <span class="hlt">bubbles</span>. Second, the <span class="hlt">bubble</span> clouds present a large surface area to volume ratio, enhancing the CO2 diffusion from the supersaturated liquid, hence growing rapidly and depleting the CO2. The clouds of <span class="hlt">bubbles</span> migrate upwards in the form of plumes pulling the surrounding liquid with them and eventually resulting in the foam overflow. The sudden pressure drop that triggers the <span class="hlt">bubble</span> dynamics with a collapse and oscillations is modelled by the Rayleigh-Plesset equation. The <span class="hlt">bubble</span> dynamics from impact to collapse occurs over a time (tb ≃ 800 μs) much larger than the acoustic time scale of the liquid bulk (tac = 2H/c ≃ 80 μs), for the experimental container of height H = 6 cm and a speed of sound around c ≃ 1500 m/s. This scale separation, together with the comparison of numerical and experimental results, suggests that the pressure drop is controlled by two parameters: the acceleration of the container and the distance from the <span class="hlt">bubble</span> to the free surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApPhL.102y4103A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApPhL.102y4103A"><span>Wetting of soap <span class="hlt">bubbles</span> on hydrophilic, hydrophobic, and superhydrophobic surfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arscott, Steve</p> <p>2013-06-01</p> <p>Wetting of sessile <span class="hlt">bubbles</span> on various wetting surfaces (solid and liquid) has been studied. A model is presented for the apparent contact angle of a sessile <span class="hlt">bubble</span> based on a modified Young's equation--the experimental results agree with the model. Wetting a hydrophilic surface results in a <span class="hlt">bubble</span> contact angle of 90° whereas using a superhydrophobic surface one observes 134°. For hydrophilic surfaces, the <span class="hlt">bubble</span> angle diminishes with <span class="hlt">bubble</span> radius whereas on a superhydrophobic surface, the <span class="hlt">bubble</span> angle increases. The size of the plateau borders governs the <span class="hlt">bubble</span> contact angle, depending on the wetting of the surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSV...371..150T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSV...371..150T"><span>Noise reduction by the application of an air-<span class="hlt">bubble</span> curtain in offshore pile driving</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsouvalas, A.; Metrikine, A. V.</p> <p>2016-06-01</p> <p>Underwater noise pollution is a by-product of marine industrial operations. In particular, the noise generated when a foundation pile is driven into the soil with an impact hammer is considered to be harmful for the aquatic species. In an attempt to reduce the ecological footprint, several noise mitigation techniques have been investigated. Among the various solutions proposed, the air-<span class="hlt">bubble</span> curtain is often applied due to its efficacy in noise reduction. In this paper, a model is proposed for the investigation of the sound reduction during marine piling when an air-<span class="hlt">bubble</span> curtain is placed around the pile. The model consists of the pile, the surrounding water and soil media, and the air-<span class="hlt">bubble</span> curtain which is positioned at a certain distance from the pile surface. The solution approach is semi-analytical and is based on the dynamic sub-structuring technique and the modal decomposition method. Two main results of the paper can be distinguished. First, a new model is proposed that can be used for predictions of the noise levels in a computationally efficient manner. Second, an analysis is presented of the principal mechanisms that are responsible for the noise reduction due to the application of the air-<span class="hlt">bubble</span> curtain in marine piling. The understanding of these mechanisms turns to be crucial for the exploitation of the maximum efficiency of the system. It is shown that the principal mechanism of noise reduction depends strongly on the frequency content of the radiated sound and the <span class="hlt">characteristics</span> of the <span class="hlt">bubbly</span> medium. For piles of large diameter which radiate most of the acoustic energy at relatively low frequencies, the noise reduction is mainly attributed to the mismatch of the acoustic impedances between the seawater and the <span class="hlt">bubbly</span> layer. On the contrary, for smaller piles and when the radiated acoustic energy is concentrated at frequencies close to, or higher than, the resonance frequency of the air <span class="hlt">bubbles</span>, the sound absorption within the <span class="hlt">bubbly</span> layer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRB..123.1060M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRB..123.1060M"><span>Gas <span class="hlt">Bubble</span> Migration and Trapping in Porous Media: Pore-Scale Simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mahabadi, Nariman; Zheng, Xianglei; Yun, Tae Sup; van Paassen, Leon; Jang, Jaewon</p> <p>2018-02-01</p> <p>Gas <span class="hlt">bubbles</span> can be naturally generated or intentionally introduced in sediments. Gas <span class="hlt">bubble</span> migration and trapping affect the rate of gas emission into the atmosphere or modify the sediment properties such as hydraulic and mechanical properties. In this study, the migration and trapping of gas <span class="hlt">bubbles</span> are simulated using the pore-network model extracted from the 3D X-ray image of in situ sediment. Two types of <span class="hlt">bubble</span> size distribution (mono-sized and distributed-sized cases) are used in the simulation. The spatial and statistical <span class="hlt">bubble</span> size distribution, residual gas saturation, and hydraulic conductivity reduction due to the <span class="hlt">bubble</span> trapping are investigated. The results show that the <span class="hlt">bubble</span> size distribution becomes wider during the gas <span class="hlt">bubble</span> migration due to <span class="hlt">bubble</span> coalescence for both mono-sized and distributed-sized cases. And the trapped <span class="hlt">bubble</span> fraction and the residual gas saturation increase as the <span class="hlt">bubble</span> size increases. The hydraulic conductivity is reduced as a result of the gas <span class="hlt">bubble</span> trapping. The reduction in hydraulic conductivity is apparently observed as <span class="hlt">bubble</span> size and the number of nucleation points increase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JCAP...12..044D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JCAP...12..044D"><span>Primordial black hole formation by vacuum <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deng, Heling; Vilenkin, Alexander</p> <p>2017-12-01</p> <p>Vacuum <span class="hlt">bubbles</span> may nucleate during the inflationary epoch and expand, reaching relativistic speeds. After inflation ends, the <span class="hlt">bubbles</span> are quickly slowed down, transferring their momentum to a shock wave that propagates outwards in the radiation background. The ultimate fate of the <span class="hlt">bubble</span> depends on its size. <span class="hlt">Bubbles</span> smaller than certain critical size collapse to ordinary black holes, while in the supercritical case the <span class="hlt">bubble</span> interior inflates, forming a baby universe, which is connected to the exterior region by a wormhole. The wormhole then closes up, turning into two black holes at its two mouths. We use numerical simulations to find the masses of black holes formed in this scenario, both in subcritical and supercritical regime. The resulting mass spectrum is extremely broad, ranging over many orders of magnitude. For some parameter values, these black holes can serve as seeds for supermassive black holes and may account for LIGO observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970000384','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970000384"><span>Acoustic Behavior of Vapor <span class="hlt">Bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prosperetti, Andrea; Oguz, Hasan N.</p> <p>1996-01-01</p> <p>In a microgravity environment vapor <span class="hlt">bubbles</span> generated at a boiling surface tend to remain near it for a long time. This affects the boiling heat transfer and in particular promotes an early transition to the highly inefficient film boiling regime. This paper describes the physical basis underlying attempts to remove the <span class="hlt">bubbles</span> by means of pressure radiation forces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850015908','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850015908"><span>Advanced detectors and signal processing for <span class="hlt">bubble</span> memories</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kryder, M. H.; Rasky, P. H. L.; Greve, D. W.</p> <p>1985-01-01</p> <p>The feasibility of combining silicon and magnetic <span class="hlt">bubble</span> technologies is demonstrated. Results of <span class="hlt">bubble</span> film annealing indicate that a low temperature silicon on garnet technology is the most likely one to succeed commercially. Annealing ambients are also shown to have a major effect on the magnetic properties of <span class="hlt">bubble</span> films. Functional MOSFETs were fabricated on <span class="hlt">bubble</span> films coated with thick (approximately 1 micron) SiO2 layers. The two main problems with these silicon on garnet MOSFETs are low electron mobilities and large gate leakage currents. Results indicate that the laser recrystallized silicon and gate oxide (SiO2) layers are contaminated. The data suggest that part of the contaminating ions originate in the sputtered oxide spacer layer and part originates in the <span class="hlt">bubble</span> film itself. A diffusion barrier, such as silicon nitride, placed between the <span class="hlt">bubble</span> film and the silicon layer should eliminate the contamination induced problem.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000AIPC..524..421H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000AIPC..524..421H"><span>The acoustic environment of a sonoluminescing <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holzfuss, Joachim; Rüggeberg, Matthias; Holt, R. Glynn</p> <p>2000-07-01</p> <p>A <span class="hlt">bubble</span> is levitated in water in a cylindrical resonator which is driven by ultrasound. It has been shown that in a certain region of parameter space the <span class="hlt">bubble</span> is emitting light pulses (sonoluminescence). One of the properties observed is the enormous spatial stability leaving the <span class="hlt">bubble</span> "pinned" in space allowing it to emit light with a timing of picosecond accuracy. We argue that the observed stability is due to interactions of the <span class="hlt">bubble</span> with the resonator. A shock wave emitted at collapse time together with a self generated complex sound field, which is experimentally mapped with high resolution, is responsible for the observed effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/136034','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/136034"><span>A simple <span class="hlt">bubble</span>-flowmeter with quasicontinuous registration.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ludt, H; Herrmann, H D</p> <p>1976-07-22</p> <p>The construction of a simple <span class="hlt">bubble</span>-flow-meter is described. The instrument has the following features: 1. automatic <span class="hlt">bubble</span> injection, 2. precise measurement of the <span class="hlt">bubble</span> passage time by a digital counter, 3. quasicontinuous registration of the flow rate, 4. alternative run with clear fluid (water) and coloured fluid (blood), 5. low volume, 6. closed measuring system for measurements in low and high pressure systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/764653','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/764653"><span><span class="hlt">Bubble</span> Formation Modeling in IE-911</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Fondeur, F.F.</p> <p>2000-09-27</p> <p>The author used diffusion modeling to determine the hydrogen and oxygen concentration inside IE-911. The study revealed gas <span class="hlt">bubble</span> nucleation will not occur in the bulk solution inside the pore or on the pore wall. This finding results from the fast oxygen and hydrogen gas molecular diffusion and a very confined pore space. The net steady state concentration of these species inside the pore proves too low to drive <span class="hlt">bubble</span> nucleation. This study did not investigate other gas <span class="hlt">bubble</span> nucleating mechanism such as suspended particles in solution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970000447','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970000447"><span>Nonlinear <span class="hlt">Bubble</span> Interactions in Acoustic Pressure Fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barbat, Tiberiu; Ashgriz, Nasser; Liu, Ching-Shi</p> <p>1996-01-01</p> <p>The systems consisting of a two-phase mixture, as clouds of <span class="hlt">bubbles</span> or drops, have shown many common features in their responses to different external force fields. One of particular interest is the effect of an unsteady pressure field applied to these systems, case in which the coupling of the vibrations induced in two neighboring components (two drops or two <span class="hlt">bubbles</span>) may result in an interaction force between them. This behavior was explained by Bjerknes by postulating that every body that is moving in an accelerating fluid is subjected to a 'kinetic buoyancy' equal with the product of the acceleration of the fluid multiplied by the mass of the fluid displaced by the body. The external sound wave applied to a system of drops/<span class="hlt">bubbles</span> triggers secondary sound waves from each component of the system. These secondary pressure fields integrated over the surface of the neighboring drop/<span class="hlt">bubble</span> may result in a force additional to the effect of the primary sound wave on each component of the system. In certain conditions, the magnitude of these secondary forces may result in significant changes in the dynamics of each component, thus in the behavior of the entire system. In a system containing <span class="hlt">bubbles</span>, the sound wave radiated by one <span class="hlt">bubble</span> at the location of a neighboring one is dominated by the volume oscillation mode and its effects can be important for a large range of frequencies. The interaction forces in a system consisting of drops are much smaller than those consisting of <span class="hlt">bubbles</span>. Therefore, as a first step towards the understanding of the drop-drop interaction subject to external pressure fluctuations, it is more convenient to study the <span class="hlt">bubble</span> interactions. This paper presents experimental results and theoretical predictions concerning the interaction and the motion of two levitated air <span class="hlt">bubbles</span> in water in the presence of an acoustic field at high frequencies (22-23 KHz).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70193584','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70193584"><span>Convection in a volcanic conduit recorded by <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Carey, Rebecca J.; Manga, Michael; Degruyter, Wim; Gonnermann, Helge M.; Swanson, Donald; Houghton, Bruce F.; Orr, Tim R.; Patrick, Matthew R.</p> <p>2013-01-01</p> <p>Microtextures of juvenile pyroclasts from Kīlauea’s (Hawai‘i) early A.D. 2008 explosive activity record the velocity and depth of convection within the basaltic magma-filled conduit. We use X-ray microtomography (μXRT) to document the spatial distribution of <span class="hlt">bubbles</span>. We find small <span class="hlt">bubbles</span> (radii from 5 μm to 70 μm) in a halo surrounding larger millimeter-size <span class="hlt">bubbles</span>. This suggests that dissolved water was enriched around the larger bubbles—the opposite of what is expected if <span class="hlt">bubbles</span> grow as water diffuses into the <span class="hlt">bubble</span>. Such volatile enrichment implies that the volatiles within the large <span class="hlt">bubbles</span> were redissolving into the melt as they descended into the conduit by the downward motion of convecting magma within the lava lake. The thickness of the small <span class="hlt">bubble</span> halo is ∼100–150 μm, consistent with water diffusing into the melt on time scales on the order of 103 s. Eruptions, triggered by rockfall, rapidly exposed this magma to lower pressures, and the haloes of melt with re-dissolved water became sufficiently supersaturated to cause nucleation of the population of smaller <span class="hlt">bubbles</span>. The required supersaturation pressures are consistent with a depth of a few hundred meters and convection velocities of the order of 0.1 m s−1, similar to the circulation velocity observed on the surface of the Halema‘uma‘u lava lake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17431757','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17431757"><span>Air <span class="hlt">bubble</span> migration is a random event post embryo transfer.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Confino, E; Zhang, J; Risquez, F</p> <p>2007-06-01</p> <p>Air <span class="hlt">bubble</span> location following embryo transfer (ET) is the presumable placement spot of embryos. The purpose of this study was to document endometrial air <span class="hlt">bubble</span> position and migration following embryo transfer. Multicenter prospective case study. Eighty-eight embryo transfers were performed under abdominal ultrasound guidance in two countries by two authors. A single or double air <span class="hlt">bubble</span> was loaded with the embryos using a soft, coaxial, end opened catheters. The embryos were slowly injected 10-20 mm from the fundus. Air <span class="hlt">bubble</span> position was recorded immediately, 30 minutes later and when the patient stood up. <span class="hlt">Bubble</span> marker location analysis revealed a random distribution without visible gravity effect when the patients stood up. The <span class="hlt">bubble</span> markers demonstrated splitting, moving in all directions and dispersion. Air <span class="hlt">bubbles</span> move and split frequently post ET with the patient in the horizontal position, suggestive of active uterine contractions. <span class="hlt">Bubble</span> migration analysis supports a rather random movement of the <span class="hlt">bubbles</span> and possibly the embryos. Standing up changed somewhat <span class="hlt">bubble</span> configuration and distribution in the uterine cavity. Gravity related <span class="hlt">bubble</span> motion was uncommon, suggesting that horizontal rest post ET may not be necessary. This report challenges the common belief that a very accurate ultrasound guided embryo placement is mandatory. The very random <span class="hlt">bubble</span> movement observed in this two-center study suggests that a large "window" of embryo placement maybe present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25595420','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25595420"><span>Measurement and modeling on hydrodynamic forces and deformation of an air <span class="hlt">bubble</span> approaching a solid sphere in liquids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shahalami, Mansoureh; Wang, Louxiang; Wu, Chu; Masliyah, Jacob H; Xu, Zhenghe; Chan, Derek Y C</p> <p>2015-03-01</p> <p>The interaction between <span class="hlt">bubbles</span> and solid surfaces is central to a broad range of industrial and biological processes. Various experimental techniques have been developed to measure the interactions of <span class="hlt">bubbles</span> approaching solids in a liquid. A main challenge is to accurately and reliably control the relative motion over a wide range of hydrodynamic conditions and at the same time to determine the interaction forces, <span class="hlt">bubble</span>-solid separation and <span class="hlt">bubble</span> deformation. Existing experimental methods are able to focus only on one of the aspects of this problem, mostly for <span class="hlt">bubbles</span> and particles with <span class="hlt">characteristic</span> dimensions either below 100 μm or above 1 cm. As a result, either the interfacial deformations are measured directly with the forces being inferred from a model, or the forces are measured directly with the deformations to be deduced from the theory. The recently developed integrated thin film drainage apparatus (ITFDA) filled the gap of intermediate <span class="hlt">bubble</span>/particle size ranges that are commonly encountered in mineral and oil recovery applications. Equipped with side-view digital cameras along with a bimorph cantilever as force sensor and speaker diaphragm as the driver for <span class="hlt">bubble</span> to approach a solid sphere, the ITFDA has the capacity to measure simultaneously and independently the forces and interfacial deformations as a <span class="hlt">bubble</span> approaches a solid sphere in a liquid. Coupled with the thin liquid film drainage modeling, the ITFDA measurement allows the critical role of surface tension, fluid viscosity and <span class="hlt">bubble</span> approach speed in determining <span class="hlt">bubble</span> deformation (profile) and hydrodynamic forces to be elucidated. Here we compare the available methods of studying <span class="hlt">bubble</span>-solid interactions and demonstrate unique features and advantages of the ITFDA for measuring both forces and <span class="hlt">bubble</span> deformations in systems of Reynolds numbers as high as 10. The consistency and accuracy of such measurement are tested against the well established Stokes-Reynolds-Young-Laplace model</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993VA.....37..469S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993VA.....37..469S"><span><span class="hlt">Bubbles</span> in extended inflation and multi-production of universes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sakai, Nobuyuki; Maeda, Kei-ichi</p> <p></p> <p>Developing the thin-wall method of Israel, we present a formalism to investigate <span class="hlt">bubble</span> dynamics in generalized Einstein theories. We derive the equations of motion for a <span class="hlt">bubble</span>, finding that the space-time inside a <span class="hlt">bubble</span> is always inhomogeneous. Applying this formalism to extended inflation, we find the following two results: (1) Any true vacuum <span class="hlt">bubble</span> expands, contrary to the results of Goldwirth-Zaglauer, who claim that <span class="hlt">bubbles</span> created initially later collapse. We show that their initial conditions for collapsing <span class="hlt">bubbles</span> are physically inconsistent. (2) Concerning the global space-time structure of the Universe in extended inflation, we show that worm-holes are produced as in old inflation, resulting in the multi-production of universes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD0662409','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD0662409"><span>GAS AND <span class="hlt">BUBBLE</span> PRODUCTION BY SIPHONOPHORES.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p></p> <p>Gas-filled siphonophore floats collected from a deep scattering layer (DSL) were photographed in the act of voluntarily expelling <span class="hlt">bubbles</span> of nearly...Such free <span class="hlt">bubbles</span>, together with the siphonophore floats themselves, constitute a biological family of potentially resonant sonar targets</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002APS..DFD.EB006M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002APS..DFD.EB006M"><span><span class="hlt">Bubble</span>-induced microstreaming: guiding and destroying lipid vesicles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marmottant, Philippe; Hilgenfeldt, Sascha</p> <p>2002-11-01</p> <p>Micron-sized <span class="hlt">bubbles</span> respond with strong oscillations when submitted to ultrasound. This has led to their use as echographic contrast enhancers. The large energy and force densities generated by the collapsing <span class="hlt">bubbles</span> also make them non-invasive mechanical tools: Recently, it has been reported that the interaction of cavitating <span class="hlt">bubbles</span> with nearby cells can render the latter permeable to large molecules (sonoporation), suggesting prospects for drug delivery and gene transfection. We have developed a laboratory setup that allows for a controlled study of the interaction of single microbubbles with single lipid bilayer vesicles. Substituting vesicles for cell membranes is advantageous because the mechanical properties of vesicles are well-known. Microscopic observations reveal that vesicles near a <span class="hlt">bubble</span> follow the vivid streaming motion set up by the <span class="hlt">bubble</span>. The vesicles "bounce" off the <span class="hlt">bubble</span>, being periodically accelerated towards and away from it, and undergo well-defined shape deformations along their trajectory in accordance with fluid-dynamical theory. Break-up of vesicles could also be observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title21-vol8/pdf/CFR-2013-title21-vol8-sec870-4205.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title21-vol8/pdf/CFR-2013-title21-vol8-sec870-4205.pdf"><span>21 CFR 870.4205 - Cardiopulmonary bypass <span class="hlt">bubble</span> detector.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-04-01</p> <p>... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass <span class="hlt">bubble</span> detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass <span class="hlt">bubble</span> detector. (a) Identification. A cardiopulmonary bypass <span class="hlt">bubble</span> detector is a device used to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title21-vol8/pdf/CFR-2010-title21-vol8-sec870-4205.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title21-vol8/pdf/CFR-2010-title21-vol8-sec870-4205.pdf"><span>21 CFR 870.4205 - Cardiopulmonary bypass <span class="hlt">bubble</span> detector.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-04-01</p> <p>... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass <span class="hlt">bubble</span> detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass <span class="hlt">bubble</span> detector. (a) Identification. A cardiopulmonary bypass <span class="hlt">bubble</span> detector is a device used to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title21-vol8/pdf/CFR-2011-title21-vol8-sec870-4205.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title21-vol8/pdf/CFR-2011-title21-vol8-sec870-4205.pdf"><span>21 CFR 870.4205 - Cardiopulmonary bypass <span class="hlt">bubble</span> detector.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-04-01</p> <p>... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass <span class="hlt">bubble</span> detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass <span class="hlt">bubble</span> detector. (a) Identification. A cardiopulmonary bypass <span class="hlt">bubble</span> detector is a device used to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title21-vol8/pdf/CFR-2014-title21-vol8-sec870-4205.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title21-vol8/pdf/CFR-2014-title21-vol8-sec870-4205.pdf"><span>21 CFR 870.4205 - Cardiopulmonary bypass <span class="hlt">bubble</span> detector.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-04-01</p> <p>... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass <span class="hlt">bubble</span> detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass <span class="hlt">bubble</span> detector. (a) Identification. A cardiopulmonary bypass <span class="hlt">bubble</span> detector is a device used to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title21-vol8/pdf/CFR-2012-title21-vol8-sec870-4205.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title21-vol8/pdf/CFR-2012-title21-vol8-sec870-4205.pdf"><span>21 CFR 870.4205 - Cardiopulmonary bypass <span class="hlt">bubble</span> detector.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-04-01</p> <p>... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass <span class="hlt">bubble</span> detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass <span class="hlt">bubble</span> detector. (a) Identification. A cardiopulmonary bypass <span class="hlt">bubble</span> detector is a device used to...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16090745','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16090745"><span>Shock wave interaction with laser-generated single <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sankin, G N; Simmons, W N; Zhu, S L; Zhong, P</p> <p>2005-07-15</p> <p>The interaction of a lithotripter shock wave (LSW) with laser-generated single vapor <span class="hlt">bubbles</span> in water is investigated using high-speed photography and pressure measurement via a fiber-optic probe hydrophone. The interaction leads to nonspherical collapse of the <span class="hlt">bubble</span> with secondary shock wave emission and microjet formation along the LSW propagation direction. The maximum pressure amplification is produced during the collapse phase of the <span class="hlt">bubble</span> oscillation when the compressive pulse duration of the LSW matches with the forced collapse time of the <span class="hlt">bubble</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005PhRvL..94r4502B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005PhRvL..94r4502B"><span>Scaling and Instabilities in <span class="hlt">Bubble</span> Pinch-Off</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burton, J. C.; Waldrep, R.; Taborek, P.</p> <p>2005-05-01</p> <p>We have used a 100 000 frame-per-second video to analyze the pinch-off of nitrogen gas <span class="hlt">bubbles</span> in fluids with a wide range of viscosity. If the external fluid is highly viscous (ηext>100 cP), the <span class="hlt">bubble</span> neck radius is proportional to the time before break, τ, and decreases smoothly to zero. If the external fluid has low viscosity (ηext<10 cP), the radius scales as τ1/2 until an instability develops in the gas <span class="hlt">bubble</span>, which causes the neck to rupture and tear apart. Finally, if the viscosity of the external fluid is in an intermediate range, an elongated thread is formed, which breaks apart into micron-sized <span class="hlt">bubbles</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22051610','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22051610"><span>Filtering microfluidic <span class="hlt">bubble</span> trains at a symmetric junction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Parthiban, Pravien; Khan, Saif A</p> <p>2012-02-07</p> <p>We report how a nominally symmetric microfluidic junction can be used to sort all <span class="hlt">bubbles</span> of an incoming train exclusively into one of its arms. The existence of this "filter" regime is unexpected, given that the junction is symmetric. We analyze this behavior by quantifying how <span class="hlt">bubbles</span> modulate the hydrodynamic resistance in microchannels and show how speeding up a <span class="hlt">bubble</span> train whilst preserving its spatial periodicity can lead to filtering at a nominally symmetric junction. We further show how such an asymmetric traffic of <span class="hlt">bubble</span> trains can be triggered in symmetric geometries by identifying conditions wherein the resistance to flow decreases with an increase in the number of <span class="hlt">bubbles</span> in the microchannel and derive an exact criterion to predict the same.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27649337','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27649337"><span>Lithotripter shock wave interaction with a <span class="hlt">bubble</span> near various biomaterials.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ohl, S W; Klaseboer, E; Szeri, A J; Khoo, B C</p> <p>2016-10-07</p> <p>Following previous work on the dynamics of an oscillating <span class="hlt">bubble</span> near a bio-material (Ohl et al 2009 Phys. Med. Biol. 54 6313-36) and the interaction of a <span class="hlt">bubble</span> with a shockwave (Klaseboer et al 2007 J. Fluid Mech. 593 33-56), the present work concerns the interaction of a gas <span class="hlt">bubble</span> with a traveling shock wave (such as from a lithotripter) in the vicinity of bio-materials such as fat, skin, muscle, cornea, cartilage, and bone. The <span class="hlt">bubble</span> is situated in water (to represent a water-like biofluid). The <span class="hlt">bubble</span> collapses are not spherically symmetric, but tend to feature a high speed jet. A few simulations are performed and compared with available experimental observations from Sankin and Zhong (2006 Phys. Rev. E 74 046304). The collapses of cavitation <span class="hlt">bubbles</span> (created by laser in the experiment) near an elastic membrane when hit by a lithotripter shock wave are correctly captured by the simulation. This is followed by a more systematic study of the effects involved concerning shockwave <span class="hlt">bubble</span> biomaterial interactions. If a subsequent rarefaction wave hits the collapsed <span class="hlt">bubble</span>, it will re-expand to a very large size straining the bio-materials nearby before collapsing once again. It is noted that, for hard bio-material like bone, reflection of the shock wave at the bone-water interface can affect the <span class="hlt">bubble</span> dynamics. Also the initial size of the <span class="hlt">bubble</span> has a significant effect. Large <span class="hlt">bubbles</span> (∼1 mm) will split into smaller <span class="hlt">bubbles</span>, while small <span class="hlt">bubbles</span> collapse with a high speed jet in the travel direction of the shock wave. The numerical model offers a computationally efficient way of understanding the complex phenomena involving the interplay of a <span class="hlt">bubble</span>, a shock wave, and a nearby bio-material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PMB....61.7031O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PMB....61.7031O"><span>Lithotripter shock wave interaction with a <span class="hlt">bubble</span> near various biomaterials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohl, S. W.; Klaseboer, E.; Szeri, A. J.; Khoo, B. C.</p> <p>2016-10-01</p> <p>Following previous work on the dynamics of an oscillating <span class="hlt">bubble</span> near a bio-material (Ohl et al 2009 Phys. Med. Biol. 54 6313-36) and the interaction of a <span class="hlt">bubble</span> with a shockwave (Klaseboer et al 2007 J. Fluid Mech. 593 33-56), the present work concerns the interaction of a gas <span class="hlt">bubble</span> with a traveling shock wave (such as from a lithotripter) in the vicinity of bio-materials such as fat, skin, muscle, cornea, cartilage, and bone. The <span class="hlt">bubble</span> is situated in water (to represent a water-like biofluid). The <span class="hlt">bubble</span> collapses are not spherically symmetric, but tend to feature a high speed jet. A few simulations are performed and compared with available experimental observations from Sankin and Zhong (2006 Phys. Rev. E 74 046304). The collapses of cavitation <span class="hlt">bubbles</span> (created by laser in the experiment) near an elastic membrane when hit by a lithotripter shock wave are correctly captured by the simulation. This is followed by a more systematic study of the effects involved concerning shockwave <span class="hlt">bubble</span> biomaterial interactions. If a subsequent rarefaction wave hits the collapsed <span class="hlt">bubble</span>, it will re-expand to a very large size straining the bio-materials nearby before collapsing once again. It is noted that, for hard bio-material like bone, reflection of the shock wave at the bone—water interface can affect the <span class="hlt">bubble</span> dynamics. Also the initial size of the <span class="hlt">bubble</span> has a significant effect. Large <span class="hlt">bubbles</span> (˜1 mm) will split into smaller <span class="hlt">bubbles</span>, while small <span class="hlt">bubbles</span> collapse with a high speed jet in the travel direction of the shock wave. The numerical model offers a computationally efficient way of understanding the complex phenomena involving the interplay of a <span class="hlt">bubble</span>, a shock wave, and a nearby bio-material.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29429710','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29429710"><span>Numerical simulation of single <span class="hlt">bubble</span> dynamics under acoustic travelling waves.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ma, Xiaojian; Huang, Biao; Li, Yikai; Chang, Qing; Qiu, Sicong; Su, Zheng; Fu, Xiaoying; Wang, Guoyu</p> <p>2018-04-01</p> <p>The objective of this paper is to apply CLSVOF method to investigate the single <span class="hlt">bubble</span> dynamics in acoustic travelling waves. The Naiver-Stokes equation considering the acoustic radiation force is proposed and validated to capture the <span class="hlt">bubble</span> behaviors. And the CLSVOF method, which can capture the continuous geometric properties and satisfies mass conservation, is applied in present work. Firstly, the regime map, depending on the dimensionless acoustic pressure amplitude and acoustic wave number, is constructed to present different <span class="hlt">bubble</span> behaviors. Then, the time evolution of the <span class="hlt">bubble</span> oscillation is investigated and analyzed. Finally, the effect of the direction and the damping coefficient of acoustic wave propagation on the <span class="hlt">bubble</span> behavior are also considered. The numerical results show that the <span class="hlt">bubble</span> presents distinct oscillation types in acoustic travelling waves, namely, volume oscillation, shape oscillation, and splitting oscillation. For the splitting oscillation, the formation of jet, splitting of <span class="hlt">bubble</span>, and the rebound of sub-<span class="hlt">bubbles</span> may lead to substantial increase in pressure fluctuations on the boundary. For the shape oscillation, the nodes and antinodes of the acoustic pressure wave contribute to the formation of the "cross shape" of the <span class="hlt">bubble</span>. It should be noted that the direction of the <span class="hlt">bubble</span> translation and <span class="hlt">bubble</span> jet are always towards the direction of wave propagation. In addition, the damping coefficient causes <span class="hlt">bubble</span> in shape oscillation to be of asymmetry in shape and inequality in size, and delays the splitting process. Copyright © 2017 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5782021-heat-transfer-three-phase-fluidization-bubble-columns-high-gas-holdups','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5782021-heat-transfer-three-phase-fluidization-bubble-columns-high-gas-holdups"><span>Heat transfer in three-phase fluidization and <span class="hlt">bubble</span>-columns with high gas holdups</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kumar, S.; Kusakabe, K.; Fan, L.S.</p> <p>1993-08-01</p> <p><span class="hlt">Bubble</span> column and three-phase fluidized bed reactors have wide applications in biotechnological and petroleum processes (Deckwer, 1985; Fan, 1989). In such biotechnological processes as fermentation and waste water treatment, small <span class="hlt">bubbles</span> of oxygen and/or nitrogen are introduced in the column to enhance oxygen transfer and to ensure the stability of immobilized cell particles. In addition, tiny <span class="hlt">bubbles</span> are produced during the biological process due to the production of surface active compounds. The presence of these small <span class="hlt">bubbles</span> causes an increase in the gas holdup of the system. High gas holdups are also <span class="hlt">characteristics</span> of industrial processes such as coal liquefactionmore » and hydrotreating of residual oils. Good understanding of the transport properties of three-phase fluidized beds with high gas holdups is essential to the design, control and optimum operations of the commercial reactors employed in the above-mentioned processes. Heat-transfer studies in three-phase fluidized beds have been reviewed recently by Kim and Laurent (1991). Past studies focused primarily on the measurements of time-averaged heat transfer from the column wall to bed (Chiu and Ziegler 1983; Muroyama et al., 1986) or on immersed heating objects to bed (Baker et al., 1978; Kato et al., 1984) in aqueous systems. Recently, Kumar et al. (1992) provided a mechanistic understanding of the heat transfer in <span class="hlt">bubbly</span>-liquid and liquid-solid systems. The purpose of this work is to investigate the heat transfer in a three-phase fluidized bed under high gas holdup conditions. The associated hydrodynamic behavior of the system is also studied.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JAP...102f3302L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JAP...102f3302L"><span>One-dimensional <span class="hlt">bubble</span> model of pulsed discharge in water</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, XinPei</p> <p>2007-09-01</p> <p>In this paper, a one-dimensional <span class="hlt">bubble</span> model of pulsed discharge in water is presented. With a total input energy of 0.63J, the simulation results show that when the <span class="hlt">bubble</span> collapses at the center of the <span class="hlt">bubble</span>, the plasma pressure oscillates strongly. It oscillates between 800 and 1150atm with an oscillation frequency of about 6.9MHz, while at r =R/2 (R: <span class="hlt">bubble</span> radius), the gas velocity oscillates intensely at the same frequency. It oscillates between -235 and 229m/s when the <span class="hlt">bubble</span> radius reaches its minimum. But it does not oscillate at r =R because of the inertia of the surrounding water. The <span class="hlt">bubble</span> collapses and reexpands with almost the same speed as that of the zero-dimensional (0D) model. This further confirms why the shock wave pressure from the 0D mode has a good agreement with the experimental results since the shock wave pressure is only determined by the <span class="hlt">bubble</span> wall velocity v(R ).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=SPIRAL+AND+MODEL&pg=3&id=EJ888756','ERIC'); return false;" href="https://eric.ed.gov/?q=SPIRAL+AND+MODEL&pg=3&id=EJ888756"><span>Rhetoric, Risk, and Markets: The Dot-Com <span class="hlt">Bubble</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Goodnight, G. Thomas; Green, Sandy Edward, Jr.</p> <p>2010-01-01</p> <p>Post-conventional economic theories are assembled to inquire into the contingent, mimetic, symbolic, and material spirals unfolding the dot-com <span class="hlt">bubble</span>, 1992-2002. The new technologies <span class="hlt">bubble</span> is reconstructed as a rhetorical movement across the practices of the hybrid market-industry risk culture of communications. The legacies of the <span class="hlt">bubble</span> task…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970000379','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970000379"><span>Production of Gas <span class="hlt">Bubbles</span> in Reduced Gravity Environments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oguz, Hasan N.; Takagi, Shu; Misawa, Masaki</p> <p>1996-01-01</p> <p>In a wide variety of applications such as waste water treatment, biological reactors, gas-liquid reactors, blood oxygenation, purification of liquids, etc., it is necessary to produce small <span class="hlt">bubbles</span> in liquids. Since gravity plays an essential role in currently available techniques, the adaptation of these applications to space requires the development of new tools. Under normal gravity, <span class="hlt">bubbles</span> are typically generated by forcing gas through an orifice in a liquid. When a growing <span class="hlt">bubble</span> becomes large enough, the buoyancy dominates the surface tension force causing it to detach from the orifice. In space, the process is quite different and the <span class="hlt">bubble</span> may remain attached to the orifice indefinitely. The most practical approach to simulating gravity seems to be imposing an ambient flow to force <span class="hlt">bubbles</span> out of the orifice. In this paper, we are interested in the effect of an imposed flow in 0 and 1 g. Specifically, we investigate the process of <span class="hlt">bubble</span> formation subject to a parallel and a cross flow. In the case of parallel flow, we have a hypodermic needle in a tube from which <span class="hlt">bubbles</span> can be produced. On the other hand, the cross flow condition is established by forcing <span class="hlt">bubbles</span> through an orifice on a wall in a shear flow. The first series of experiments have been performed under normal gravity conditions and the working fluid was water. A high quality microgravity facility has been used for the second type and silicone oil is used as the host liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/10146236-further-experimentation-bubble-generation-during-transformer-overload-final-report','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/10146236-further-experimentation-bubble-generation-during-transformer-overload-final-report"><span>Further experimentation on <span class="hlt">bubble</span> generation during transformer overload. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Oommen, T.V.</p> <p>1992-03-01</p> <p>This report covers additional work done during 1990 and 1991 on gas <span class="hlt">bubble</span> generation under overload conditions. To improve visual <span class="hlt">bubble</span> detection, a single disc coil was used. To further improve detection, a corona device was also used which signaled the onset of corona activity in the early stages of <span class="hlt">bubble</span> formation. A total of fourteen model tests were conducted, half of which used the Inertaire system, and the remaining, a conservator (COPS). Moisture content of paper in the coil varied from 1.0% to 8.0%; gas (nitrogen) content varied from 1.0% to 8.8%. The results confirmed earlier observations that themore » mathematical <span class="hlt">bubble</span> prediction model was not valid for high gas content model with relatively low moisture levels in the coil. An empirical relationship was formulated to accurately predict <span class="hlt">bubble</span> evolution temperatures from known moisture and gas content values. For low moisture content models (below 2%), the simple Piper relationship was sufficient to predict <span class="hlt">bubble</span> evolution temperatures, regardless of gas content. Moisture in the coil appears to be the key factor in <span class="hlt">bubble</span> generation. Gas blanketed (Inertaire) systems do not appear to be prone to premature <span class="hlt">bubble</span> generation from overloads as previously thought. The new <span class="hlt">bubble</span> prediction model reveals that for a coil with 2% moisture, the <span class="hlt">bubble</span> evolution temperature would be about 140{degrees}C. Since old transformers in service may have as much as 2% moisture in paper, the 140{degrees}C <span class="hlt">bubble</span> evolution temperature may be taken as the lower limit of <span class="hlt">bubble</span> evolution temperature under overload conditions for operating transformers. Drier insulation would raise the <span class="hlt">bubble</span> evolution temperature.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFDG11002E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFDG11002E"><span>How do <span class="hlt">bubbles</span> grow in a weakly supersaturated solution?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Enriquez, Oscar; Sun, Chao; Lohse, Detlef; Prosperetti, Andrea; van der Meer, Devaraj</p> <p>2013-11-01</p> <p>Beer, champagne and soft-drinks are water-based solutions which owe their ``bubbliness'' to a moderate degree of carbon dioxide supersaturation. <span class="hlt">Bubbles</span> grow sequentially from nucleation sites due to solute concentration gradients and detach due to buoyancy. The leading mass transfer mechanism is diffusion, but the advection caused by the moving surface also plays an important role. Now, what happens at the limit of very weak supersaturation? We take an experimental look at CO2 <span class="hlt">bubbles</span> growing in water under such a condition. Nucleation sites are provided by hydrophobic micro-cavities on a silicon chip, therefore controlling the number and position of <span class="hlt">bubbles</span>. Although advection is negligible, measured growth rates for an isolated <span class="hlt">bubble</span> differ noticeably from a purely diffusive theoretical solution. We can explain the differences as effects of the concentration boundary layer around the <span class="hlt">bubble</span>. Initially, its interaction with the surface on which the <span class="hlt">bubble</span> grows slows the process down. Later on, the growth rate is enhanced by buoyancy effects caused by the depletion of the solute in the surroundings of the <span class="hlt">bubble</span>. When neighboring <span class="hlt">bubbles</span> are brought into play they interact through their boundary layers, further slowing down their growth rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080004012','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080004012"><span>Three-dimensional magnetic <span class="hlt">bubble</span> memory system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor); Wu, Jiin-Chuan (Inventor)</p> <p>1994-01-01</p> <p>A compact memory uses magnetic <span class="hlt">bubble</span> technology for providing data storage. A three-dimensional arrangement, in the form of stacks of magnetic <span class="hlt">bubble</span> layers, is used to achieve high volumetric storage density. Output tracks are used within each layer to allow data to be accessed uniquely and unambiguously. Storage can be achieved using either current access or field access magnetic <span class="hlt">bubble</span> technology. Optical sensing via the Faraday effect is used to detect data. Optical sensing facilitates the accessing of data from within the three-dimensional package and lends itself to parallel operation for supporting high data rates and vector and parallel processing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OAst...26..233V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OAst...26..233V"><span>Star formation in shells of colliding multi-SNe <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasiliev, Evgenii O.; Shchekinov, Yuri A.</p> <p>2017-12-01</p> <p>It is believed that when <span class="hlt">bubbles</span> formed by multiple supernovae explosions interact with one another, they stimulate star formation in overlapping shells. We consider the evolution of a shocked layer formed by the collision of two identical <span class="hlt">bubbles</span> each of which originated from OB clusters of ˜ 50 members and ˜ 50 pc. The clusters are separated by 200-400 pc.We found that depending on evolutionary status of colliding <span class="hlt">bubbles</span> the shocked layer can either be destroyed into diffuse lumps, or be fragmented into dense clumps: the former occurs in collisions of young <span class="hlt">bubbles</span> with continuing supernovae explosions, and the latter occurs in older <span class="hlt">bubble</span> interactions.We argue that fragmentation efficiency in shells depends on external heating: for a heating rate <˜ 1.7×10-24 erg s-1 the number of fragments formed in a collision of two old <span class="hlt">bubbles</span> reaches several tens at t ˜ 4 Myr, while a heating rate >˜ 7 × 10-24 erg s-1 prevents fragmentation. The clumps formed in freely expanding parts of <span class="hlt">bubbles</span> are gradually destroyed and disappear on t <˜ 1 Myr,whereas those formed in the overlapping shells survive much longer. Because of this the number of fragments in an isolated <span class="hlt">bubble</span> begins to decrease after reaching a maximum, while in collision of two old <span class="hlt">bubbles</span> it fluctuates around 60-70 until longer than t ˜ 5 Myr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4284549','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4284549"><span>Ethnic diversity deflates price <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Levine, Sheen S.; Apfelbaum, Evan P.; Bernard, Mark; Bartelt, Valerie L.; Zajac, Edward J.; Stark, David</p> <p>2014-01-01</p> <p>Markets are central to modern society, so their failures can be devastating. Here, we examine a prominent failure: price <span class="hlt">bubbles</span>. <span class="hlt">Bubbles</span> emerge when traders err collectively in pricing, causing misfit between market prices and the true values of assets. The causes of such collective errors remain elusive. We propose that <span class="hlt">bubbles</span> are affected by ethnic homogeneity in the market and can be thwarted by diversity. In homogenous markets, traders place undue confidence in the decisions of others. Less likely to scrutinize others’ decisions, traders are more likely to accept prices that deviate from true values. To test this, we constructed experimental markets in Southeast Asia and North America, where participants traded stocks to earn money. We randomly assigned participants to ethnically homogeneous or diverse markets. We find a marked difference: Across markets and locations, market prices fit true values 58% better in diverse markets. The effect is similar across sites, despite sizeable differences in culture and ethnic composition. Specifically, in homogenous markets, overpricing is higher as traders are more likely to accept speculative prices. Their pricing errors are more correlated than in diverse markets. In addition, when <span class="hlt">bubbles</span> burst, homogenous markets crash more severely. The findings suggest that price <span class="hlt">bubbles</span> arise not only from individual errors or financial conditions, but also from the social context of decision making. The evidence may inform public discussion on ethnic diversity: it may be beneficial not only for providing variety in perspectives and skills, but also because diversity facilitates friction that enhances deliberation and upends conformity. PMID:25404313</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25404313','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25404313"><span>Ethnic diversity deflates price <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Levine, Sheen S; Apfelbaum, Evan P; Bernard, Mark; Bartelt, Valerie L; Zajac, Edward J; Stark, David</p> <p>2014-12-30</p> <p>Markets are central to modern society, so their failures can be devastating. Here, we examine a prominent failure: price <span class="hlt">bubbles</span>. <span class="hlt">Bubbles</span> emerge when traders err collectively in pricing, causing misfit between market prices and the true values of assets. The causes of such collective errors remain elusive. We propose that <span class="hlt">bubbles</span> are affected by ethnic homogeneity in the market and can be thwarted by diversity. In homogenous markets, traders place undue confidence in the decisions of others. Less likely to scrutinize others' decisions, traders are more likely to accept prices that deviate from true values. To test this, we constructed experimental markets in Southeast Asia and North America, where participants traded stocks to earn money. We randomly assigned participants to ethnically homogeneous or diverse markets. We find a marked difference: Across markets and locations, market prices fit true values 58% better in diverse markets. The effect is similar across sites, despite sizeable differences in culture and ethnic composition. Specifically, in homogenous markets, overpricing is higher as traders are more likely to accept speculative prices. Their pricing errors are more correlated than in diverse markets. In addition, when <span class="hlt">bubbles</span> burst, homogenous markets crash more severely. The findings suggest that price <span class="hlt">bubbles</span> arise not only from individual errors or financial conditions, but also from the social context of decision making. The evidence may inform public discussion on ethnic diversity: it may be beneficial not only for providing variety in perspectives and skills, but also because diversity facilitates friction that enhances deliberation and upends conformity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24648277','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24648277"><span>Improving electrokinetic microdevice stability by controlling electrolysis <span class="hlt">bubbles</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Hwi Yong; Barber, Cedrick; Minerick, Adrienne R</p> <p>2014-07-01</p> <p>The voltage-operating window for many electrokinetic microdevices is limited by electrolysis gas <span class="hlt">bubbles</span> that destabilize microfluidic system causing noise and irreproducible responses above ∼3 V DC and less than ∼1 kHz AC at 3 Vpp. Surfactant additives, SDS and Triton X-100, and an integrated semipermeable SnakeSkin® membrane were employed to control and assess electrolysis <span class="hlt">bubbles</span> from platinum electrodes in a 180 by 70 μm, 10 mm long microchannel. Stabilized current responses at 100 V DC were observed with surfactant additives or SnakeSkin® barriers. Electrolysis <span class="hlt">bubble</span> behaviors, visualized via video microscopy at the electrode surface and in the microchannels, were found to be influenced by surfactant function and SnakeSkin® barriers. Both SDS and Triton X-100 surfactants promoted smaller <span class="hlt">bubble</span> diameters and faster <span class="hlt">bubble</span> detachment from electrode surfaces via increasing gas solubility. In contrast, SnakeSkin® membranes enhanced natural convection and blocked <span class="hlt">bubbles</span> from entering the microchannels and thus reduced current disturbances in the electric field. This data illustrated that electrode surface behaviors had substantially greater impacts on current stability than microbubbles within microchannels. Thus, physically blocking <span class="hlt">bubbles</span> from microchannels is less effective than electrode functionalization approaches to stabilize electrokinetic microfluidic systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26840001','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26840001"><span>Influence of mass transfer on <span class="hlt">bubble</span> plume hydrodynamics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lima Neto, Iran E; Parente, Priscila A B</p> <p>2016-03-01</p> <p>This paper presents an integral model to evaluate the impact of gas transfer on the hydrodynamics of <span class="hlt">bubble</span> plumes. The model is based on the Gaussian type self-similarity and functional relationships for the entrainment coefficient and factor of momentum amplification due to turbulence. The impact of mass transfer on <span class="hlt">bubble</span> plume hydrodynamics is investigated considering different <span class="hlt">bubble</span> sizes, gas flow rates and water depths. The results revealed a relevant impact when fine <span class="hlt">bubbles</span> are considered, even for moderate water depths. Additionally, model simulations indicate that for weak <span class="hlt">bubble</span> plumes (i.e., with relatively low flow rates and large depths and slip velocities), both dissolution and turbulence can affect plume hydrodynamics, which demonstrates the importance of taking the momentum amplification factor relationship into account. For deeper water conditions, simulations of <span class="hlt">bubble</span> dissolution/decompression using the present model and classical models available in the literature resulted in a very good agreement for both aeration and oxygenation processes. Sensitivity analysis showed that the water depth, followed by the <span class="hlt">bubble</span> size and the flow rate are the most important parameters that affect plume hydrodynamics. Lastly, dimensionless correlations are proposed to assess the impact of mass transfer on plume hydrodynamics, including both the aeration and oxygenation modes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020014640&hterms=crisis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcrisis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020014640&hterms=crisis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcrisis"><span>Evolution of Vapor <span class="hlt">Bubbles</span> Nucleation Sites in Low Gravity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Buyevich, Yu A.; Webbon, Bruce W.</p> <p>1995-01-01</p> <p>When liquid is expelled by a vapor <span class="hlt">bubble</span> growing at a nucleation site on a superheated surface, a thin microlayer underneath the <span class="hlt">bubble</span> is left behind. It is evaporated from the free microlayer surface that provides for <span class="hlt">bubble</span> growth. The average thickness of the microlayer determining the evaporation rate increases with time if the latter does not exceed a threshold value associated with the burn-out crisis. The <span class="hlt">bubble</span> is described as a spherical segment with its flattened part adjoining the microlayer. This introduces two independent variables - the radius of the spherical part of the <span class="hlt">bubble</span> surface and the polar angle that defines the relative area of the flattened part. They are to be found out from a set of two strongly nonlinear equations resulting from mass and momentum conservation laws. The first one depends on both microlayer thickness and nonmonotonously changing <span class="hlt">bubble</span> base area. The second involves two major factors favoring <span class="hlt">bubble</span> detachment - the buoyancy and a force due to the initial momentum of vapor input into the <span class="hlt">bubble</span>. The former force depends on gravity whereas the latter one does not. It is why the limiting regimes of <span class="hlt">bubble</span> evolution that correspond to normal or moderately reduced gravity and to microgravity feature drastically different properties. In the first case, the buoyancy dominates and the <span class="hlt">bubble</span> evolves in such a manner as to become a full sphere at a moment that can be viewed as that of detachment. The detachment volume grows as gravity decreases. In the second case, the buoyancy is negligible and the <span class="hlt">bubble</span> stays near the surface, while its volume continues to increase for a sufficiently long time. The findings are discussed in connection with experimental data obtained under different gravity conditions, some unpublished experiments being included. They help to understand why the pool boiling heat transfer coefficient frequently increases as gravity falls down and eventually vanishes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=Glass+AND+bubble&id=EJ325707','ERIC'); return false;" href="https://eric.ed.gov/?q=Glass+AND+bubble&id=EJ325707"><span>Tiny <span class="hlt">Bubbles</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kim, Hy</p> <p>1985-01-01</p> <p>A simple oxygen-collecting device (easily constructed from glass jars and a lid) can show <span class="hlt">bubbles</span> released by water plants during photosynthesis. Suggestions are given for: (1) testing the collected gas; (2) using various carbon dioxide sources; and (3) measuring respiration. (DH)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22493858-time-resolved-imaging-electrical-discharge-development-underwater-bubbles','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22493858-time-resolved-imaging-electrical-discharge-development-underwater-bubbles"><span>Time-resolved imaging of electrical discharge development in underwater <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tu, Yalong; Xia, Hualei; Yang, Yong, E-mail: yangyong@hust.edu.cn, E-mail: luxinpei@hust.edu.cn</p> <p>2016-01-15</p> <p>The formation and development of plasma in single air <span class="hlt">bubbles</span> submerged in water were investigated. The difference in the discharge dynamics and the after-effects on the <span class="hlt">bubble</span> were investigated using a 900 000 frame per second high-speed charge-coupled device camera. It was observed that depending on the position of the electrodes, the breakdown could be categorized into two modes: (1) direct discharge mode, where the high voltage and ground electrodes were in contact with the <span class="hlt">bubble</span>, and the streamer would follow the shortest path and propagate along the axis of the <span class="hlt">bubble</span> and (2) dielectric barrier mode, where the groundmore » electrode was not in touch with the <span class="hlt">bubble</span> surface, and the streamer would form along the inner surface of the <span class="hlt">bubble</span>. The oscillation of the <span class="hlt">bubble</span> and the development of instabilities on the <span class="hlt">bubble</span> surface were also discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JLTP..187..618Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JLTP..187..618Y"><span>Exploding and Imaging of Electron <span class="hlt">Bubbles</span> in Liquid Helium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yadav, Neha; Vadakkumbatt, Vaisakh; Maris, Humphrey J.; Ghosh, Ambarish</p> <p>2017-06-01</p> <p>An electron <span class="hlt">bubble</span> in liquid helium-4 under the saturated vapor pressure becomes unstable and explodes if the pressure becomes more negative than -1.9 bars. In this paper, we use focused ultrasound to explode electron <span class="hlt">bubbles</span>. We then image at 30,000 frames per second the growth and subsequent collapse of the <span class="hlt">bubbles</span>. We find that <span class="hlt">bubbles</span> can grow to as large as 1 mm in diameter within 2 ms after the cavitation event. We examine the relation between the maximum size of the <span class="hlt">bubble</span> and the lifetime and find good agreement with the experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810026241&hterms=dissolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddissolution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810026241&hterms=dissolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddissolution"><span>Dissolution of multicomponent <span class="hlt">bubbles</span>. [gases in glass melts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weinberg, M. C.; Subramanian, R. S.</p> <p>1980-01-01</p> <p>The behavior of an isolated, stationary, multicomponent gas <span class="hlt">bubble</span> in a glassmelt containing several dissolved gases is considered. The relevant mass-transport equations are formulated and calculations are performed for the case of two diffusing gases using a quasi-stationary model and a numerical solution of the exact mass-transfer equations. The results obtained from these two approaches are compared. The factors which govern the dissolution or growth of a <span class="hlt">bubble</span> are thermodynamic and kinetic in origin. The tendency of a <span class="hlt">bubble</span> to grow or shrink at long times is controlled by departure from overall equilibrium, whereas the short-time <span class="hlt">bubble</span> dynamics may be dominated by kinetic effects. As a result of the existence of these dual influences, maxima and/or minima occur in the functional dependence of the <span class="hlt">bubble</span> radius on time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFDR12005J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFDR12005J"><span>Interaction of a vortex ring and a <span class="hlt">bubble</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jha, Narsing K.; Govardhan, Raghuraman N.</p> <p>2014-11-01</p> <p>Micro-<span class="hlt">bubble</span> injection in to boundary layers is one possible method for reducing frictional drag of ships. Although this has been studied for some time, the physical mechanisms responsible for drag reduction using microbubbles in turbulent boundary layers is not yet fully understood. Previous studies suggest that <span class="hlt">bubble</span>-vortical structure interaction seems to be one of the important physical mechanisms for frictional drag reduction using microbubbles. In the present work, we study a simplification of this problem, namely, the interaction of a single vortical structure, in particular a vortex ring, with a single <span class="hlt">bubble</span> for better understanding of the physics. The vortex ring is generated using a piston-cylinder arrangement and the <span class="hlt">bubble</span> is generated by connecting a capillary to an air pump. The <span class="hlt">bubble</span> dynamics is directly visualized using a high speed camera, while the vorticity modification is measured using time resolved PIV. The results show that significant deformations can occur of both the <span class="hlt">bubble</span> and the vortex ring. Effect of different non-dimensional parameters on the interaction will be presented in the meeting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.473.1570Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.473.1570Y"><span>The variance of dispersion measure of high-redshift transient objects as a probe of ionized <span class="hlt">bubble</span> size during reionization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoshiura, Shintaro; Takahashi, Keitaro</p> <p>2018-01-01</p> <p>The dispersion measure (DM) of high-redshift (z ≳ 6) transient objects such as fast radio bursts can be a powerful tool to probe the intergalactic medium during the Epoch of Reionization. In this paper, we study the variance of the DMs of objects with the same redshift as a potential probe of the size distribution of ionized <span class="hlt">bubbles</span>. We calculate the DM variance with a simple model with randomly distributed spherical <span class="hlt">bubbles</span>. It is found that the DM variance reflects the <span class="hlt">characteristics</span> of the probability distribution of the <span class="hlt">bubble</span> size. We find that the variance can be measured precisely enough to obtain the information on the typical size with a few hundred sources at a single redshift.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhPro..67..386S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhPro..67..386S"><span>Simulation Studies on Cooling of Cryogenic Propellant by Gas <span class="hlt">Bubbling</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sandilya, Pavitra; Saha, Pritam; Sengupta, Sonali</p> <p></p> <p>Injection cooling was proposed to store cryogenic liquids (Larsen et al. [1], Schmidt [2]). When a non-condensable gas is injected through a liquid, the liquid component would evaporate into the <span class="hlt">bubble</span> if its partial pressure in the <span class="hlt">bubble</span> is lower than its vapour pressure. This would tend to cool the liquid. Earlier works on injection cooling was analysed by Larsen et al. [1], Schmidt [2], Cho et al. [3] and Jung et al. [4], considering instantaneous mass transfer and finite heat transfer between gas <span class="hlt">bubble</span> and liquid. It is felt that <span class="hlt">bubble</span> dynamics (break up, coalescence, deformation, trajectory etc.) should also play a significant role in liquid cooling. The reported work are based on simple assumptions like single <span class="hlt">bubble</span>, zero <span class="hlt">bubble</span> deformation, and no inter-<span class="hlt">bubble</span> interactions. Hence in this work, we propose a lumped parameter model considering both heat and mass interactions between <span class="hlt">bubble</span> and the liquid to gain a preliminary insight into the cooling phenomenon during gas injection through a liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3156824','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3156824"><span>Size limits the formation of liquid jets during <span class="hlt">bubble</span> bursting</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lee, Ji San; Weon, Byung Mook; Park, Su Ji; Je, Jung Ho; Fezzaa, Kamel; Lee, Wah-Keat</p> <p>2011-01-01</p> <p>A <span class="hlt">bubble</span> reaching an air–liquid interface usually bursts and forms a liquid jet. Jetting is relevant to climate and health as it is a source of aerosol droplets from breaking waves. Jetting has been observed for large <span class="hlt">bubbles</span> with radii of R≫100 μm. However, few studies have been devoted to small <span class="hlt">bubbles</span> (R<100 μm) despite the entrainment of a large number of such <span class="hlt">bubbles</span> in sea water. Here we show that jet formation is inhibited by <span class="hlt">bubble</span> size; a jet is not formed during bursting for <span class="hlt">bubbles</span> smaller than a critical size. Using ultrafast X-ray and optical imaging methods, we build a phase diagram for jetting and the absence of jetting. Our results demonstrate that jetting in <span class="hlt">bubble</span> bursting is analogous to pinching-off in liquid coalescence. The coalescence mechanism for <span class="hlt">bubble</span> bursting may be useful in preventing jet formation in industry and improving climate models concerning aerosol production. PMID:21694715</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5935447','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5935447"><span>Review—Physicochemical hydrodynamics of gas <span class="hlt">bubbles</span> in two phase electrochemical systems</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Taqieddin, Amir; Nazari, Roya; Rajic, Ljiljana; Alshawabkeh, Akram</p> <p>2018-01-01</p> <p>Electrochemical systems suffer from poor management of evolving gas <span class="hlt">bubbles</span>. Improved understanding of <span class="hlt">bubbles</span> behavior helps to reduce overpotential, save energy and enhance the mass transfer during chemical reactions. This work investigates and reviews the gas <span class="hlt">bubbles</span> hydrodynamics, behavior, and management in electrochemical cells. Although the rate of <span class="hlt">bubble</span> growth over the electrode surface is well understood, there is no reliable prediction of <span class="hlt">bubbles</span> break-off diameter from the electrode surface because of the complexity of <span class="hlt">bubbles</span> motion near the electrode surface. Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) are the most common experimental techniques to measure <span class="hlt">bubble</span> dynamics. Although the PIV is faster than LDA, both techniques are considered expensive and time-consuming. This encourages adapting Computational Fluid Dynamics (CFD) methods as an alternative to study <span class="hlt">bubbles</span> behavior. However, further development of CFD methods is required to include coalescence and break-up of <span class="hlt">bubbles</span> for better understanding and accuracy. The disadvantages of CFD methods can be overcome by using hybrid methods. The behavior of <span class="hlt">bubbles</span> in electrochemical systems is still a complex challenging topic which requires a better understanding of the gas <span class="hlt">bubbles</span> hydrodynamics and their interactions with the electrode surface and bulk liquid, as well as between the <span class="hlt">bubbles</span> itself. PMID:29731515</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29731515','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29731515"><span>Review-Physicochemical hydrodynamics of gas <span class="hlt">bubbles</span> in two phase electrochemical systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taqieddin, Amir; Nazari, Roya; Rajic, Ljiljana; Alshawabkeh, Akram</p> <p>2017-01-01</p> <p>Electrochemical systems suffer from poor management of evolving gas <span class="hlt">bubbles</span>. Improved understanding of <span class="hlt">bubbles</span> behavior helps to reduce overpotential, save energy and enhance the mass transfer during chemical reactions. This work investigates and reviews the gas <span class="hlt">bubbles</span> hydrodynamics, behavior, and management in electrochemical cells. Although the rate of <span class="hlt">bubble</span> growth over the electrode surface is well understood, there is no reliable prediction of <span class="hlt">bubbles</span> break-off diameter from the electrode surface because of the complexity of <span class="hlt">bubbles</span> motion near the electrode surface. Particle Image Velocimetry (PIV) and Laser Doppler Anemometry (LDA) are the most common experimental techniques to measure <span class="hlt">bubble</span> dynamics. Although the PIV is faster than LDA, both techniques are considered expensive and time-consuming. This encourages adapting Computational Fluid Dynamics (CFD) methods as an alternative to study <span class="hlt">bubbles</span> behavior. However, further development of CFD methods is required to include coalescence and break-up of <span class="hlt">bubbles</span> for better understanding and accuracy. The disadvantages of CFD methods can be overcome by using hybrid methods. The behavior of <span class="hlt">bubbles</span> in electrochemical systems is still a complex challenging topic which requires a better understanding of the gas <span class="hlt">bubbles</span> hydrodynamics and their interactions with the electrode surface and bulk liquid, as well as between the <span class="hlt">bubbles</span> itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19257138','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19257138"><span>Dynamics of sonoluminescing <span class="hlt">bubbles</span> within a liquid hammer device.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Urteaga, Raúl; García-Martínez, Pablo Luis; Bonetto, Fabián J</p> <p>2009-01-01</p> <p>We studied the dynamics of a single sonoluminescing <span class="hlt">bubble</span> (SBSL) in a liquid hammer device. In particular, we investigated the phosphoric acid-xenon system, in which pulses up to four orders of magnitude brighter than SBSL in water systems (about 10;{12} photons per pulse) have been previously reported [Chakravarty, Phys. Rev. E 69, 066317 (2004)]. We used stroboscopic photography and a Mie scattering technique in order to measure the radius evolution of the <span class="hlt">bubbles</span>. Under adequate conditions we may position a <span class="hlt">bubble</span> at the bottom of the tube (cavity) and a second <span class="hlt">bubble</span> trapped at the middle of the tube (upper <span class="hlt">bubble</span>). During its collapse, the cavity produces the compression of the liquid column. This compression drives impulsively the dynamics of the upper <span class="hlt">bubble</span>. Our measurements reveal that the observed light emissions produced by the upper <span class="hlt">bubble</span> are generated at its second collapse. We employed a simple numerical model to investigate the conditions that occur during the upper <span class="hlt">bubble</span> collapse. We found good agreement between numerical and experimental values for the light intensity (fluence) and light pulse widths. Results from the model show that the light emission is increased mainly due to an increase in noble gas ambient radius and not because the maximum temperature increases. Even for the brightest pulses obtained ( 2x10;{13} photons, about 20W of peak power) the maximum temperatures computed for the upper <span class="hlt">bubble</span> are always lower than 20000K .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800000496&hterms=Glass+bubble&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGlass%2Bbubble','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800000496&hterms=Glass+bubble&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGlass%2Bbubble"><span>Driving <span class="hlt">bubbles</span> out of glass</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mattox, D. M.</p> <p>1981-01-01</p> <p>Surface tension gradient in melt forces gas <span class="hlt">bubbles</span> to surface, increasing glass strength and transparency. Conventional chemical and buoyant fining are extremely slow in viscous glasses, but tension gradient method moves 250 um <span class="hlt">bubbles</span> as rapidly as 30 um/s. Heat required for high temperature part of melt is furnished by stationary electrical or natural-gas heater; induction and laser heating are also possible. Method has many applications in industry processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.A51D2093K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.A51D2093K"><span>Dynamic <span class="hlt">Bubble</span> Surface Tension Measurements in Northwest Atlantic Seawater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kieber, D. J.; Long, M. S.; Keene, W. C.; Kinsey, J. D.; Frossard, A. A.; Beaupre, S. R.; Duplessis, P.; Maben, J. R.; Lu, X.; Chang, R.; Zhu, Y.; Bisgrove, J.</p> <p>2017-12-01</p> <p>Numerous reports suggest that most organic matter (OM) associated with newly formed primary marine aerosol (PMA) originates from the sea-surface microlayer. However, surface-active OM rapidly adsorbs onto <span class="hlt">bubble</span> surfaces in the water column and is ejected into the atmosphere when <span class="hlt">bubbles</span> burst at the air-water interface. Here we present dynamic surface tension measurements of <span class="hlt">bubbles</span> produced in near surface seawater from biologically productive and oligotrophic sites and in deep seawater collected from 2500 m in the northwest Atlantic. In all cases, the surface tension of <span class="hlt">bubble</span> surfaces decreased within seconds after the <span class="hlt">bubbles</span> were exposed to seawater. These observations demonstrate that <span class="hlt">bubble</span> surfaces are rapidly saturated by surfactant material scavenged from seawater. Spatial and diel variability in <span class="hlt">bubble</span> surface evolution indicate corresponding variability in surfactant concentrations and/or composition. Our results reveal that surface-active OM is found throughout the water column, and that at least some surfactants are not of recent biological origin. Our results also support the hypothesis that the surface microlayer is a minor to negligible source of OM associated with freshly produced PMA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhPl...25e2113T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhPl...25e2113T"><span>Observation of high-temperature <span class="hlt">bubbles</span> in an ECR plasma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Terasaka, K.; Yoshimura, S.; Tanaka, M. Y.</p> <p>2018-05-01</p> <p>Creation and annihilation of high-temperature <span class="hlt">bubbles</span> have been observed in an electron cyclotron resonance plasma. The electron temperature in the <span class="hlt">bubble</span> core is three times higher than that in the ambient region, and the size perpendicular to the magnetic field is much smaller than the plasma diameter. Formation of a <span class="hlt">bubble</span> accompanies large negative spikes in the floating potential of a Langmuir probe, and the spatiotemporal behavior of the <span class="hlt">bubble</span> has been visualized with a high-impedance wire grid detector. It is found that the <span class="hlt">bubble</span> is in a prolate spheroidal shape with the axis along the magnetic field and occurs randomly in time and independently in space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.G7009I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.G7009I"><span><span class="hlt">Bubble</span> clustering in a glass of stout beer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iwatsubo, Fumiya; Watamura, Tomoaki; Sugiyama, Kazuyasu</p> <p>2017-11-01</p> <p>To clarify why the texture in stout beer poured into a pint glass descends, we investigated local time development of the void fraction and velocity of <span class="hlt">bubbles</span>. The propagation of the number density distribution, i.e. the texture, appearing near the inclined wall is observed. We visualized individual advective <span class="hlt">bubbles</span> near the inclined wall by microscope and measured the local void fraction using brightness of images while the velocity of <span class="hlt">bubbles</span> by means of Particle Tracking Velocimetry. As the result of measurements, we found the local void fraction and the <span class="hlt">bubbles</span> advection velocity increase and decrease repeatedly with a time delay. We conclude the texture pattern is composed of fluid blobs which contain less <span class="hlt">bubbles</span>; extruding and suction flows respectively toward and from the interior of the container form respectively in front and back of the blobs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3259670','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3259670"><span>Observations of the collapses and rebounds of millimeter-sized lithotripsy <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kreider, Wayne; Crum, Lawrence A.; Bailey, Michael R.; Sapozhnikov, Oleg A.</p> <p>2011-01-01</p> <p><span class="hlt">Bubbles</span> excited by lithotripter shock waves undergo a prolonged growth followed by an inertial collapse and rebounds. In addition to the relevance for clinical lithotripsy treatments, such <span class="hlt">bubbles</span> can be used to study the mechanics of inertial collapses. In particular, both phase change and diffusion among vapor and noncondensable gas molecules inside the <span class="hlt">bubble</span> are known to alter the collapse dynamics of individual <span class="hlt">bubbles</span>. Accordingly, the role of heat and mass transport during inertial collapses is explored by experimentally observing the collapses and rebounds of lithotripsy <span class="hlt">bubbles</span> for water temperatures ranging from 20 to 60 °C and dissolved gas concentrations from 10 to 85% of saturation. <span class="hlt">Bubble</span> responses were characterized through high-speed photography and acoustic measurements that identified the timing of individual <span class="hlt">bubble</span> collapses. Maximum <span class="hlt">bubble</span> diameters before and after collapse were estimated and the corresponding ratio of volumes was used to estimate the fraction of energy retained by the <span class="hlt">bubble</span> through collapse. The rebounds demonstrated statistically significant dependencies on both dissolved gas concentration and temperature. In many observations, liquid jets indicating asymmetric <span class="hlt">bubble</span> collapses were visible. <span class="hlt">Bubble</span> rebounds were sensitive to these asymmetries primarily for water conditions corresponding to the most dissipative collapses. PMID:22088027</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996PhRvD..54.5031Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996PhRvD..54.5031Y"><span>Quantum fluctuations and CMB anisotropies in one-<span class="hlt">bubble</span> open inflation models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamamoto, Kazuhiro; Sasaki, Misao; Tanaka, Takahiro</p> <p>1996-10-01</p> <p>We first develop a method to calculate a complete set of mode functions that describe the quantum fluctuations generated in one-<span class="hlt">bubble</span> open inflation models. We consider two classes of models. One is a single scalar field model proposed by Bucher, Goldhaber, and Turok and by us as an example of the open inflation scenario, and the other is a two-field model such as the ``supernatural'' inflation proposed by Linde and Mezhlumian. In both cases we assume the difference in the vacuum energy density between inside and outside the <span class="hlt">bubble</span> is negligible. There are two kinds of mode functions. One kind has the usual continuous spectrum and the other has a discrete spectrum with <span class="hlt">characteristic</span> wavelengths exceeding the spatial curvature scale. The latter can be further divided into two classes in terms of its origin. One is called the de Sitter supercurvature mode, which arises due to the global spacetime structure of de Sitter space, and the other is due to fluctuations of the <span class="hlt">bubble</span> wall. We calculate the spectrum of quantum fluctuations in these models and evaluate the resulting large angular scale CMB anisotropies. We find there are ranges of model parameters that are consistent with observed CMB anisotropies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990PhFlA...2.1412B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990PhFlA...2.1412B"><span>On the structure of nonlinear waves in liquids with gas <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beylich, Alfred E.; Gülhan, Ali</p> <p>1990-08-01</p> <p>Transient wave phenomena in two-phase mixtures with a liquid as the matrix and gas <span class="hlt">bubbles</span> as the dispersed phase have been studied in a shock tube using glycerine as the liquid and He, N2, and SF6 as gases having a large variation in the ratio of specific heats and the thermal diffusivity. Two different sizes of <span class="hlt">bubble</span> radii have been produced , R0=1.15 and 1.6 mm, with a dispersion in size of less than 5%. The void fraction was varied over one order of magnitude, φ0=0.2%-2%. The measured pressure profiles were averaged by superimposing many shots, typically 20. Speeds and profiles were measured for shock waves and for wave packets. Investigation of the wave structure allows one to approach the fundamental question of how the physics on the level of the microstructure influences the behavior on the macroscale. In the theoretical work, modeling on the basis of a hierarchy of <span class="hlt">characteristic</span> length scales is developed. <span class="hlt">Bubble</span> interactions, transient heat transfer, and dissipation due to molecular and bulk viscosities are included. Solutions for small void fractions and moderate amplitudes are obtained for the steady cases of shock waves and solitons and are compared with the experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDE33006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDE33006C"><span>Influences of source condition and dissolution on <span class="hlt">bubble</span> plume in a stratified environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Shigan; Prosperetti, Andrea</p> <p>2017-11-01</p> <p>A cross-sectionally averaged model is used to study a <span class="hlt">bubble</span> plume <span class="hlt">rising</span> in a stratified quiescent liquid. Scaling analyses for the peel height, at which the plume momentum vanishes, and the neutral height, at which its average density equals the ambient density, are presented. Contrary to a widespread practice in the literature, it is argued that the neutral height cannot be identified with the experimentally reported intrusion height. Recognizing this difference provides an explanation of the reason why the intrusion height is found so frequently to lie so much above predictions, and brings the theoretical results in line with observations. The mathematical model depends on three dimensionless parameters, some of which are related to the inlet conditions at the plume source. Their influence on the peel and neutral heights is illustrated by means of numerical results. Aside from the source parameters, we incorporate dissolution of <span class="hlt">bubbles</span> and the corresponding density change of plume into the model. Contrary to what's documented in literature, density change of plume due to dissolution plays an important role in keeping the total buoyancy of plume, thus alleviating the rapid decrease of peel height because of dissolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6732927-new-solutions-steady-bubbles-hele-shaw-cell','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6732927-new-solutions-steady-bubbles-hele-shaw-cell"><span>New solutions for steady <span class="hlt">bubbles</span> in a Hele-Shaw cell</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Tanveer, S.</p> <p>1987-03-01</p> <p>Exact solutions are presented for steadily moving <span class="hlt">bubbles</span> in a Hele--Shaw cell when the effect of surface tension is neglected. These solutions form a three-parameter family. For specified area, both the speed of the <span class="hlt">bubble</span> and the distance of its centroid from the channel centerline remain arbitrary when surface tension is ignored. However, numerical evidence suggests that this twofold arbitrariness is removed by the effect of surface tension, i.e., for given <span class="hlt">bubble</span> area and surface tension, solutions exist only when the <span class="hlt">bubble</span> velocity and the centroid distance from the channel centerline attain one or more isolated values. From a limitedmore » numerical search, no nonsymmetric solutions could be found; however, a branch of symmetric <span class="hlt">bubble</span> solutions that was not found in earlier work was found. This branch corresponds to one of the Romero-Vanden-Broeck branch of finger solutions when the <span class="hlt">bubble</span> size is large. A new procedure for numerical calculations of <span class="hlt">bubble</span> solutions in the presence of surface tension is presented and is found to work very well for reasonably large <span class="hlt">bubbles</span>, unlike the previous method of Tanveer (Phys. Fluids 29, 3537 (1986)). The precise power law dependence of <span class="hlt">bubble</span> velocity on surface tension for small surface tension is explored for <span class="hlt">bubbles</span> of different area. Agreement is noted with recent analytical results for a finger.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25019874','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25019874"><span>Single-<span class="hlt">bubble</span> dynamics in pool boiling of one-component fluids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Xinpeng; Qian, Tiezheng</p> <p>2014-06-01</p> <p>We numerically investigate the pool boiling of one-component fluids with a focus on the effects of surface wettability on the single-<span class="hlt">bubble</span> dynamics. We employed the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)], a diffuse-interface model for liquid-vapor flows involving liquid-vapor transition in nonuniform temperature fields. We first perform simulations for <span class="hlt">bubbles</span> on homogeneous surfaces. We find that an increase in either the contact angle or the surface superheating can enhance the <span class="hlt">bubble</span> spreading over the heating surface and increase the <span class="hlt">bubble</span> departure diameter as well and therefore facilitate the transition into film boiling. We then examine the dynamics of <span class="hlt">bubbles</span> on patterned surfaces, which incorporate the advantages of both hydrophobic and hydrophilic surfaces. The central hydrophobic region increases the thermodynamic probability of <span class="hlt">bubble</span> nucleation while the surrounding hydrophilic region hinders the continuous <span class="hlt">bubble</span> spreading by pinning the contact line at the hydrophobic-hydrophilic intersection. This leads to a small <span class="hlt">bubble</span> departure diameter and therefore prevents the transition from nucleate boiling into film boiling. With the <span class="hlt">bubble</span> nucleation probability increased and the <span class="hlt">bubble</span> departure facilitated, the efficiency of heat transfer on such patterned surfaces is highly enhanced, as observed experimentally [Int. J. Heat Mass Transfer 57, 733 (2013)]. In addition, the stick-slip motion of contact line on patterned surfaces is demonstrated in one-component fluids, with the effect weakened by surface superheating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29705527','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29705527"><span>Efficiencies of Tritium (3H) <span class="hlt">bubbling</span> systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Duda, Jean-Marie; Le Goff, Pierre; Leblois, Yoan; Ponsard, Samuel</p> <p>2018-09-01</p> <p><span class="hlt">Bubbling</span> systems are among the devices most used by nuclear operators to measure atmospheric tritium activity in their facilities or the neighbouring environment. However, information about trapping efficiency and <span class="hlt">bubbling</span> system oxidation is not accessible and/or, at best, only minimally supported by demonstrations in actual operating conditions. In order to evaluate easily these parameters and thereby meet actual normative and regulatory requirements, a statistical study was carried out over 2000 monitoring records from the CEA Valduc site. From this data collection obtained over recent years of monitoring the CEA Valduc facilities and environment, a direct relation was highlighted between the 3H-samplers trapping efficiency of tritium as tritiated water and the sampling time and conditions of use: temperature and atmospheric moisture. It was thus demonstrated that this efficiency originated from two sources. The first one is intrinsic to the <span class="hlt">bubbling</span> system operating parameters and the sampling time. That part applies equally to all four bubblers. The second part, however, is specific to the first bubbler. In essence, it depends on the sampling time and the sampled air <span class="hlt">characteristics</span>. It was also highlighted that the water volume variation in the first bubbler, between the beginning and the end of the sampling process, is directly related to the average water concentration of the sampled air. In this way, it was possible to model the variations in trapping efficiency of the 3H-samplers relative to the sampling time and the water volume variation in the first bubbler. This model makes it possible to obtain the quantities required to comply with the current standards governing the monitoring of radionuclides in the environment and to associate an uncertainty concerning the measurements as well as the sampling parameters. Copyright © 2018 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DMP.G3005T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DMP.G3005T"><span>Impurity <span class="hlt">bubbles</span> in a BEC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Timmermans, Eddy; Blinova, Alina; Boshier, Malcolm</p> <p>2013-05-01</p> <p>Polarons (particles that interact with the self-consistent deformation of the host medium that contains them) self-localize when strongly coupled. Dilute Bose-Einstein condensates (BECs) doped with neutral distinguishable atoms (impurities) and armed with a Feshbach-tuned impurity-boson interaction provide a unique laboratory to study self-localized polarons. In nature, self-localized polarons come in two flavors that exhibit qualitatively different behavior: In lattice systems, the deformation is slight and the particle is accompanied by a cloud of collective excitations as in the case of the Landau-Pekar polarons of electrons in a dielectric lattice. In natural fluids and gases, the strongly coupled particle radically alters the medium, e.g. by expelling the host medium as in the case of the electron <span class="hlt">bubbles</span> in superfluid helium. We show that BEC-impurities can self-localize in a <span class="hlt">bubble</span>, as well as in a Landau-Pekar polaron state. The BEC-impurity system is fully characterized by only two dimensionless coupling constants. In the corresponding phase diagram the <span class="hlt">bubble</span> and Landau-Pekar polaron limits correspond to large islands separated by a cross-over region. The same BEC-impurity species can be adiabatically Feshbach steered from the Landau-Pekar to the <span class="hlt">bubble</span> regime. This work was funded by the Los Alamos LDRD program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3460979','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3460979"><span>Models of cylindrical <span class="hlt">bubble</span> pulsation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hay, Todd A.; Hamilton, Mark F.</p> <p>2012-01-01</p> <p>Three models are considered for describing the dynamics of a pulsating cylindrical <span class="hlt">bubble</span>. A linear solution is derived for a cylindrical <span class="hlt">bubble</span> in an infinite compressible liquid. The solution accounts for losses due to viscosity, heat conduction, and acoustic radiation. It reveals that radiation is the dominant loss mechanism, and that it is 22 times greater than for a spherical <span class="hlt">bubble</span> of the same radius. The predicted resonance frequency provides a basis of comparison for limiting forms of other models. The second model considered is a commonly used equation in Rayleigh-Plesset form that requires an incompressible liquid to be finite in extent in order for <span class="hlt">bubble</span> pulsation to occur. The radial extent of the liquid becomes a fitting parameter, and it is found that considerably different values of the parameter are required for modeling inertial motion versus acoustical oscillations. The third model was developed by V. K. Kedrinskii [Hydrodynamics of Explosion (Springer, New York, 2005), pp. 23–26] in the form of the Gilmore equation for compressible liquids of infinite extent. While the correct resonance frequency and loss factor are not recovered from this model in the linear approximation, it provides reasonable agreement with observations of inertial motion. PMID:22978863</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950006440','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950006440"><span>Guest investigator program study: Physics of equatorial plasma <span class="hlt">bubbles</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tsunoda, Roland T.</p> <p>1994-01-01</p> <p>Plasma <span class="hlt">bubbles</span> are large-scale (10 to 100 km) depletions in plasma density found in the night-time equatorial ionosphere. Their formation has been found to entail the upward transport of plasma over hundreds of kilometers in altitude, suggesting that <span class="hlt">bubbles</span> play significant roles in the physics of many of the diverse and unique features found in the low-latitude ionosphere. In the simplest scenario, plasma <span class="hlt">bubbles</span> appear first as perturbations in the bottomside F layer, which is linearly unstable to the gravitationally driven Rayleigh-Taylor instability. Once initiated, <span class="hlt">bubbles</span> develop upward through the peak of the F layer into its topside (sometimes to altitudes in excess of 1000 km), a behavior predicted by the nonlinear form of the same instability. While good general agreement has been found between theory and observations, little is known about the detailed physics associated with plasma <span class="hlt">bubbles</span>. Our research activity centered around two topics: the shape of plasma <span class="hlt">bubbles</span> and associated electric fields, and the day-to-day variability in the occurrence of plasma <span class="hlt">bubbles</span>. The first topic was pursued because of a divergence in view regarding the nonlinear physics associated with plasma <span class="hlt">bubble</span> development. While the development of perturbations in isodensity contours in the bottomside F layer into plasma <span class="hlt">bubbles</span> is well accepted, some believed <span class="hlt">bubbles</span> to be cylinder-like closed regions of depleted plasma density that floated upward leaving a turbulent wake behind them (e.g., Woodman and LaHoz, 1976; Ott, 1978; Kelley and Ott, 1978). Our results, summarized in a paper submitted to the Journal of Geophysical Research, consisted of incoherent scatter radar measurements that showed unambiguously that the depleted region is wedgelike and not cylinderlike, and a case study and modeling of SM-D electric field instrument (EFI) measurements that showed that the absence of electric-field perturbations outside the plasma-depleted region is a distinct signature of wedge</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AIPC.1359..330K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AIPC.1359..330K"><span>Characterisation of gene delivery using liposomal <span class="hlt">bubbles</span> and ultrasound</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koshima, Risa; Suzuki, Ryo; Oda, Yusuke; Hirata, Keiichi; Nomura, Tetsuya; Negishi, Yoichi; Utoguchi, Naoki; Kudo, Nobuki; Maruyama, Kazuo</p> <p>2011-09-01</p> <p>The combination of nano/microbubbles and ultrasound is a novel technique for a non-viral gene deliver. We have previously developed novel ultrasound sensitive liposomes (<span class="hlt">Bubble</span> liposomes) which contain the ultrasound imaging gas perfluoropropane. In this study, <span class="hlt">Bubble</span> liposomes were compared with cationic lipid (CL)-DNA complexes as potential gene delivery carriers into tumors in vivo. The delivery of genes by <span class="hlt">bubble</span> liposomes depended on the intensity of the applied ultrasound. The transfection efficiency plateaued at 0.7 W/cm2 ultrasound intensity. <span class="hlt">Bubble</span> liposomes efficiently transferred genes into cultured cells even when the cells were exposed to ultrasound for only 1 s. In addition, <span class="hlt">bubble</span> liposomes were able to introduce the luciferase gene more effectively than CL-DNA complexes into mouse ascites tumor cells. We conclude that the combination of <span class="hlt">Bubble</span> liposomes and ultrasound is a good method for gene transfer in vivo.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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