Science.gov

Sample records for particle movement solids

  1. Characteristics of movement of solid particle in snow-water mixtures

    NASA Astrophysics Data System (ADS)

    Sasaki, Mikio

    2009-02-01

    In the present study, experimental observations for the movement of solid particles in the solid-water mixture flow were carried out in the horizontal pipe with a high-speed camera. When flow is slow, the picture was taken at 1000 scenes per second, and when flow is fast, the flow observation catches the solid particle very clearly at 4000 scenes per second. From the flow observation of the solid-water multi-phase flow that the solid specific gravity is near that of the transportation fluid, the change of the solid particle position and the speed change of the solid particle were shown in the present study. Within the scope of the present study, the following conclusions were derived. The solid particle flows with moving up and down. The change of the speed is large. The speeds in the lower layer and upper layer are both great fluctuations because the change of the speed near the wall is large. On the other hand, the vicinity of the solid particle in the middle layer of the pipe fluctuates a little and a steady speed continues. The solid particle near the wall rotates greatly, however, the solid particle in the middle layer of the pipe shows a small rotation. The rotation means that the flow of the mixtures is not Bingham flow.

  2. Intragastric movement assessment by measuring magnetic field decay of magnetised tracer particles in a solid meal.

    PubMed

    Forsman, M

    2000-03-01

    The aim of the study is to evaluate and further develop a non-invasive method for the measurement of intragastric movements. Ferrimagnetic particles (gamma-Fe2O3) are ingested within a standard test meal (pancakes), and given a permanent magnetisation by an applied homogeneous magnetic field. Magnetic measurements are performed outside the stomach, using fluxgate magnetometers anterior and posterior, in seven periods of 12 minutes each. Any movements caused by grinding and mixing in the ingesta would result in a misalignment of the magnetic moments, and hence in a decay of the external magnetic field. Twelve healthy male volunteers, aged 26.7 +/- 2.7 years (mean +/- SD), are studied. After an initial phase of low and almost linear flux density decay (32 +/- 19%, from minute 10 to minute 22 postprandially), the mean rotation and decay gradually increases (67 +/- 21%, from minute 100 to 112), and the decay becomes bi-exponential. It is hypothesised that the bi-exponential nature of the decay corresponds to the relative fractions, solid and semifluid, of gastric content. The decay curves often show superimposed 3 cycles min-1 variations, which correlate well with the basic electrical rhythm of the stomach measured by electrogastrography (EGG). It is concluded that these variations are induced by gastric contractions. PMID:10829409

  3. The movement of particles in liquid metals under gravity forces and the interaction of particles with advancing solid-liquid interface

    NASA Technical Reports Server (NTRS)

    Weinberg, F.

    1984-01-01

    The problems of shrinkage and gas porosity are discussed. Gravity forces enhance the removal of gas bubbles from a metal melt and contribute to the feeding of shrinkage porosity in castings. Experiments are reviewed which determine how large a density difference is required for metal particles to float or sink in a metal melt and to what extent do factors not considered in Stokes Law influence particle movement in a real system. As to the interaction of particles with an advancing solid-liquid interface, the results indicate that the metal particles are not rejected in a metal melt, and that concentrations of particles in a metal following solidification are due to other factors.

  4. Movement of particles using sequentially activated dielectrophoretic particle trapping

    DOEpatents

    Miles, Robin R.

    2004-02-03

    Manipulation of DNA and cells/spores using dielectrophoretic (DEP) forces to perform sample preparation protocols for polymerized chain reaction (PCR) based assays for various applications. This is accomplished by movement of particles using sequentially activated dielectrophoretic particle trapping. DEP forces induce a dipole in particles, and these particles can be trapped in non-uniform fields. The particles can be trapped in the high field strength region of one set of electrodes. By switching off this field and switching on an adjacent electrodes, particles can be moved down a channel with little or no flow.

  5. Mars - Wind friction speeds for particle movement

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Leach, R.; White, B.; Iversen, J.; Pollack, J.

    1976-01-01

    Wind friction threshold speeds for particle movement were determined in a low pressure boundary layer wind tunnel at an atmospheric pressure of 5.3 mb. The results imply that for comparable pressures on Mars, the minimum wind friction threshold speed is about 2.5 m/sec, which would require free-stream winds of 50 to 135 m/sec, depending on the character of the surface and the atmospheric conditions. The corresponding wind speeds at the height of the Viking lander meteorology instrument would be about a factor of two less than the free-stream wind speed. The particle size most easily moved by winds on Mars is about 160 microns; particles both larger and smaller than this (at least down to about 5 microns) require stronger winds to initiate movement.

  6. In Situ Solid Particle Generator

    NASA Technical Reports Server (NTRS)

    Agui, Juan H.; Vijayakumar, R.

    2013-01-01

    Particle seeding is a key diagnostic component of filter testing and flow imaging techniques. Typical particle generators rely on pressurized air or gas sources to propel the particles into the flow field. Other techniques involve liquid droplet atomizers. These conventional techniques have drawbacks that include challenging access to the flow field, flow and pressure disturbances to the investigated flow, and they are prohibitive in high-temperature, non-standard, extreme, and closed-system flow conditions and environments. In this concept, the particles are supplied directly within a flow environment. A particle sample cartridge containing the particles is positioned somewhere inside the flow field. The particles are ejected into the flow by mechanical brush/wiper feeding and sieving that takes place within the cartridge chamber. Some aspects of this concept are based on established material handling techniques, but they have not been used previously in the current configuration, in combination with flow seeding concepts, and in the current operational mode. Unlike other particle generation methods, this concept has control over the particle size range ejected, breaks up agglomerates, and is gravity-independent. This makes this device useful for testing in microgravity environments.

  7. Movement mechanisms of gross solids in intermittent flow.

    PubMed

    Littlewood, K; Butler, D

    2003-01-01

    Gross solids, such as used tampons, sanitary towels and faecal stools, are introduced into the sewer network via the WC. Although small diameter pipes (< or = 150mm diameter) make up a large proportion of most sewer networks, the transport behaviour of gross solids in these smaller pipes is not fully established. In particular, there are concerns about the effect of water conservation measures on the transport of gross solids in the intermittent flow regime prevalent in small pipes. This paper introduces a study carried out on the movement of solids in this flow regime. An extensive series of experiments has been carried out to investigate the movement mechanisms and behaviour in detail. It was found that there are three different mechanisms of movement, and photographic evidence is provided in the paper. The concept and implications of the "limiting solid transport distance" is also introduced. It is argued that solid movement is dependent on factors other than just WC flush volume and that increased blockage potential is not inevitable. PMID:12666800

  8. Electronically shielded solid state charged particle detector

    DOEpatents

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1996-08-20

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig.

  9. Electronically shielded solid state charged particle detector

    DOEpatents

    Balmer, David K.; Haverty, Thomas W.; Nordin, Carl W.; Tyree, William H.

    1996-08-20

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite.

  10. Particle behavior in solid propellant rockets

    NASA Technical Reports Server (NTRS)

    Netzer, D. W.; Diloreto, V. D.; Dubrov, E.

    1980-01-01

    The use of holography, high speed motion pictures, light scattering measurements, and post-fire particle collection/scanning electron microscopic examination to study the combustion of composite solid propellants is discussed. The relative advantages and disadvantages of the different experimental techniques for obtaining two-phase flow characteristics within the combustion environment of a solid propellant grain are evaluated. Combustion bomb studies using high speed motion pictures and post-fire residue analysis were completed for six low metal content propellants. Resolution capabilities and the relationships between post-fire residue and motion picture data are determined. Initial testing using a holocamera together with a 2D windowed motor is also described.

  11. Stochastic analysis of particle movement over a dune bed

    USGS Publications Warehouse

    Lee, Baum K.; Jobson, Harvey E.

    1977-01-01

    Stochastic models are available that can be used to predict the transport and dispersion of bed-material sediment particles in an alluvial channel. These models are based on the proposition that the movement of a single bed-material sediment particle consists of a series of steps of random length separated by rest periods of random duration and, therefore, application of the models requires a knowledge of the probability distributions of the step lengths, the rest periods, the elevation of particle deposition, and the elevation of particle erosion. The procedure was tested by determining distributions from bed profiles formed in a large laboratory flume with a coarse sand as the bed material. The elevation of particle deposition and the elevation of particle erosion can be considered to be identically distributed, and their distribution can be described by either a ' truncated Gaussian ' or a ' triangular ' density function. The conditional probability distribution of the rest period given the elevation of particle deposition closely followed the two-parameter gamma distribution. The conditional probability distribution of the step length given the elevation of particle erosion and the elevation of particle deposition also closely followed the two-parameter gamma density function. For a given flow, the scale and shape parameters describing the gamma probability distributions can be expressed as functions of bed-elevation. (Woodard-USGS)

  12. Experimental detection of transverse particle movement with structured light.

    PubMed

    Rosales-Guzmán, Carmelo; Hermosa, Nathaniel; Belmonte, Aniceto; Torres, Juan P

    2013-10-02

    One procedure widely used to detect the velocity of a moving object is by using the Doppler effect. This is the perceived change in frequency of a wave caused by the relative motion between the emitter and the detector, or between the detector and a reflecting target. The relative movement, in turn, generates a time-varying phase which translates into the detected frequency shift. The classical longitudinal Doppler effect is sensitive only to the velocity of the target along the line-of-sight between the emitter and the detector (longitudinal velocity), since any transverse velocity generates no frequency shift. This makes the transverse velocity undetectable in the classical scheme. Although there exists a relativistic transverse Doppler effect, it gives values that are too small for the typical velocities involved in most laser remote sensing applications. Here we experimentally demonstrate a novel way to detect transverse velocities. The key concept is the use of structured light beams. These beams are unique in the sense that their phases can be engineered such that each point in its transverse plane has an associated phase value. When a particle moves across the beam, the reflected light will carry information about the particle's movement through the variation of the phase of the light that reaches the detector, producing a frequency shift associated with the movement of the particle in the transverse plane.

  13. Experimental detection of transverse particle movement with structured light.

    PubMed

    Rosales-Guzmán, Carmelo; Hermosa, Nathaniel; Belmonte, Aniceto; Torres, Juan P

    2013-01-01

    One procedure widely used to detect the velocity of a moving object is by using the Doppler effect. This is the perceived change in frequency of a wave caused by the relative motion between the emitter and the detector, or between the detector and a reflecting target. The relative movement, in turn, generates a time-varying phase which translates into the detected frequency shift. The classical longitudinal Doppler effect is sensitive only to the velocity of the target along the line-of-sight between the emitter and the detector (longitudinal velocity), since any transverse velocity generates no frequency shift. This makes the transverse velocity undetectable in the classical scheme. Although there exists a relativistic transverse Doppler effect, it gives values that are too small for the typical velocities involved in most laser remote sensing applications. Here we experimentally demonstrate a novel way to detect transverse velocities. The key concept is the use of structured light beams. These beams are unique in the sense that their phases can be engineered such that each point in its transverse plane has an associated phase value. When a particle moves across the beam, the reflected light will carry information about the particle's movement through the variation of the phase of the light that reaches the detector, producing a frequency shift associated with the movement of the particle in the transverse plane. PMID:24085150

  14. Elementary Particle Spectroscopy in Regular Solid Rewrite

    NASA Astrophysics Data System (ADS)

    Trell, Erik

    2008-10-01

    The Nilpotent Universal Computer Rewrite System (NUCRS) has operationalized the radical ontological dilemma of Nothing at All versus Anything at All down to the ground recursive syntax and principal mathematical realisation of this categorical dichotomy as such and so governing all its sui generis modalities, leading to fulfilment of their individual terms and compass when the respective choice sequence operations are brought to closure. Focussing on the general grammar, NUCRS by pure logic and its algebraic notations hence bootstraps Quantum Mechanics, aware that it "is the likely keystone of a fundamental computational foundation" also for e.g. physics, molecular biology and neuroscience. The present work deals with classical geometry where morphology is the modality, and ventures that the ancient regular solids are its specific rewrite system, in effect extensively anticipating the detailed elementary particle spectroscopy, and further on to essential structures at large both over the inorganic and organic realms. The geodetic antipode to Nothing is extension, with natural eigenvector the endless straight line which when deployed according to the NUCRS as well as Plotelemeian topographic prescriptions forms a real three-dimensional eigenspace with cubical eigenelements where observed quark-skewed quantum-chromodynamical particle events self-generate as an Aristotelean phase transition between the straight and round extremes of absolute endlessness under the symmetry- and gauge-preserving, canonical coset decomposition SO(3)×O(5) of Lie algebra SU(3). The cubical eigen-space and eigen-elements are the parental state and frame, and the other solids are a range of transition matrix elements and portions adapting to the spherical root vector symmetries and so reproducibly reproducing the elementary particle spectroscopy, including a modular, truncated octahedron nano-composition of the Electron which piecemeal enter into molecular structures or compressed to each

  15. Elementary Particle Spectroscopy in Regular Solid Rewrite

    SciTech Connect

    Trell, Erik

    2008-10-17

    The Nilpotent Universal Computer Rewrite System (NUCRS) has operationalized the radical ontological dilemma of Nothing at All versus Anything at All down to the ground recursive syntax and principal mathematical realisation of this categorical dichotomy as such and so governing all its sui generis modalities, leading to fulfilment of their individual terms and compass when the respective choice sequence operations are brought to closure. Focussing on the general grammar, NUCRS by pure logic and its algebraic notations hence bootstraps Quantum Mechanics, aware that it ''is the likely keystone of a fundamental computational foundation'' also for e.g. physics, molecular biology and neuroscience. The present work deals with classical geometry where morphology is the modality, and ventures that the ancient regular solids are its specific rewrite system, in effect extensively anticipating the detailed elementary particle spectroscopy, and further on to essential structures at large both over the inorganic and organic realms. The geodetic antipode to Nothing is extension, with natural eigenvector the endless straight line which when deployed according to the NUCRS as well as Plotelemeian topographic prescriptions forms a real three-dimensional eigenspace with cubical eigenelements where observed quark-skewed quantum-chromodynamical particle events self-generate as an Aristotelean phase transition between the straight and round extremes of absolute endlessness under the symmetry- and gauge-preserving, canonical coset decomposition SO(3)xO(5) of Lie algebra SU(3). The cubical eigen-space and eigen-elements are the parental state and frame, and the other solids are a range of transition matrix elements and portions adapting to the spherical root vector symmetries and so reproducibly reproducing the elementary particle spectroscopy, including a modular, truncated octahedron nano-composition of the Electron which piecemeal enter into molecular structures or compressed to each

  16. Holographic investigation of solid propellant combustion particles

    NASA Astrophysics Data System (ADS)

    Mellin, P. J.

    1983-12-01

    This investigation continued the development of a method for obtaining high quality holograms of the combustion products from aluminized solid rocket motor propellants burned in a two-dimensional motor to provide a cross-flow environment. The use of glass side plates as a motor casing provided both a convenient construction technique and allowed good quality holograms to be obtained. At combustion pressures above 500 psia and propellant slab thicknesses greater than 0.080 inches, the timing of the laser pulse during the burn was found to be critical, since an extremely short time interval existed between the establishment of steady state slab burning and the generation of too much smoke/combustion products to permit laser penetration. As desired operating pressures increase and aluminum powder particle sizes decrease, it will probably be necessary to use thinner propellant slabs.

  17. Solid particle erosion of polymers and composites

    NASA Astrophysics Data System (ADS)

    Friedrich, K.; Almajid, A. A.

    2014-05-01

    After a general introduction to the subject of solid particle erosion of polymers and composites, the presentation focusses more specifically on the behavior of unidirectional carbon fiber (CF) reinforced polyetheretherketone (PEEK) composites under such loadings, using different impact conditions and erodents. The data were analyzed on the basis of a newly defined specific erosive wear rate, allowing a better comparison of erosion data achieved under various testing conditions. Characteristic wear mechanisms of the CF/PEEK composites consisted of fiber fracture, matrix cutting and plastic matrix deformation, the relative contribution of which depended on the impingement angles and the CF orientation. The highest wear rates were measured for impingement angles between 45 and 60°. Using abrasion resistant neat polymer films (in this case PEEK or thermoplastic polyurethane (TPU) ones) on the surface of a harder substrate (e.g. a CF/PEEK composite plate) resulted in much lower specific erosive wear rates. The use of such polymeric films can be considered as a possible method to protect composite surfaces from damage caused by minor impacts and erosion. In fact, they are nowadays already successfully applied as protections for wind energy rotor blades.

  18. Experimental characterization of solid particle transport by slug flow using Particle Image Velocimetry

    NASA Astrophysics Data System (ADS)

    Goharzadeh, A.; Rodgers, P.

    2009-02-01

    This paper presents an experimental study of gas-liquid slug flow on solid particle transport inside a horizontal pipe with two types of experiments conducted. The influence of slug length on solid particle transportation is characterized using high speed photography. Using combined Particle Image Velocimetry (PIV) with Refractive Index Matching (RIM) and fluorescent tracers (two-phase oil-air loop) the velocity distribution inside the slug body is measured. Combining these experimental analyses, an insight is provided into the physical mechanism of solid particle transportation due to slug flow. It was observed that the slug body significantly influences solid particle mobility. The physical mechanism of solid particle transportation was found to be discontinuous. The inactive region (in terms of solid particle transport) upstream of the slug nose was quantified as a function of gas-liquid composition and solid particle size. Measured velocity distributions showed a significant drop in velocity magnitude immediately upstream of the slug nose and therefore the critical velocity for solid particle lifting is reached further upstream.

  19. Kinetic behavior of solid particles in fluidized beds

    SciTech Connect

    Kono, H.O.

    1990-06-01

    The overall objectives of this project are to develop experimental techniques for measuring the forces of fluidized particles, and to predict the solid-gas performance in fluidized beds by using data analysis system, and by elucidating the intrinsic mechanism of erosion and attrition phenomena in fluidized beds. The reduction of erosion and attrition rates is one of the critical engineering problems for the design and operation of fluidized bed combustors. Specifically, the objectives are to: (1) develop the experimental techniques to measure the forces of solid particles prevailing in fluidized beds: (2) measure and characterize the forces of solid particles in various types of fluidized beds with various configurations (conventional and spouted fluidized beds) and with different scales (10, 20, and 30cm) under various fluidization conditions (particle size, bed aspect ratio and gas velocity); (3) find and verify the mechanism of erosion rates of in-bed tubes and attrition rates of fluidized particles by forces of solid particles in fluidized beds. We developed three different kinds of measurement methods, i.e., fracture sensitive sensor, piezoelectric sensor and gas pressure fluctuation method. By using these methods the exact forces of solid particles, including the transient corporate in fluidized beds, were systematically measured. Simultaneously, the erosion rates of in-bed tubes and attrition rates of fluidized particles were measured. 69 figs., 9 tabs.

  20. Foam drainage in the presence of solid particles.

    PubMed

    Wang, J; Nguyen, A V

    2016-03-28

    We conducted forced drainage experiments to study the liquid flow within the foams stabilized by a cationic surfactant (CTAB) in the presence of partially hydrophobic silica particles. The results show that the presence of solid particles, even when present in small amounts (0.0932 g L(-1) foam), can significantly decrease the foam permeability. The scaling behaviour (power law) between the drainage velocity and the imposed flow rate indicates that the presence of solid particles in the foams triggers a transition of the foam drainage regime from a node-dominated regime to a Plateau border-dominated regime. We applied two foam drainage equations for aqueous foams to simulate the experimental data and interpret the transition. The simulation results show that the presence of solid particles in the foams increases the rigidity of the interfaces and the viscous losses in the channels (the Plateau borders) of the foams, and decreases the foam permeability. We also generalize the theory for the effects of unattached hydrophilic particles on foam drainage by considering the effects of hydrophobicity and concentration of solid particles on the confinement of foam networks. This study explores liquid drainage in three-phase foams and is relevant to the field of hydrophobic particle separation by froth flotation, in which the wash water is commonly applied to the froth layer to improve the product grade.

  1. A continuum theory of a lubrication problem with solid particles

    SciTech Connect

    Dai, F.; Khonsari, M. M. )

    1993-03-01

    The governing equations for a two-dimensional lubrication problem involving the mixture of a Newtonian fluid with solid particles at an arbitrary volume fraction are developed using the theory of interacting continuua (mixture theory). The equations take the interaction between the fluid and the particles into consideration. Provision is made for the possibility of particle slippage at the boundaries. The equations are simplified assuming that the solid volume fraction varies in the sliding direction alone. Equations are solved for the velocity of the fluid phase and that of the solid phase of the mixture flow in the clearance space of an arbitrary shaped bearing. It is shown that the classical pure fluid case can be recovered as a special case of the solutions presented. Extensive numerical solutions are presented to quantify the effect of particulate solid for a number of pertinent performance parameters for both slider and journal bearings. Included in the results are discussions on the influence of particle slippage on the boundaries as well as the role of the interacting body force between the fluid and solid particles. 13 refs.

  2. Optical trapping and Raman spectroscopy of solid particles.

    PubMed

    Rkiouak, L; Tang, M J; Camp, J C J; McGregor, J; Watson, I M; Cox, R A; Kalberer, M; Ward, A D; Pope, F D

    2014-06-21

    The heterogeneous interactions of gas molecules on solid particles are crucial in many areas of science, engineering and technology. Such interactions play a critical role in atmospheric chemistry and in heterogeneous catalysis, a key technology in the energy and chemical industries. Investigating heterogeneous interactions upon single levitated particles can provide significant insight into these important processes. Various methodologies exist for levitating micron sized particles including: optical, electrical and acoustic techniques. Prior to this study, the optical levitation of solid micron scale particles has proved difficult to achieve over timescales relevant to the above applications. In this work, a new vertically configured counter propagating dual beam optical trap was optimized to levitate a range of solid particles in air. Silica (SiO2), α-alumina (Al2O3), titania (TiO2) and polystyrene were stably trapped with a high trapping efficiency (Q = 0.42). The longest stable trapping experiment was conducted continuously for 24 hours, and there are no obvious constraints on trapping time beyond this period. Therefore, the methodology described in this paper should be of major benefit to various research communities. The strength of the new technique is demonstrated by the simultaneous levitation and spectroscopic interrogation of silica particles by Raman spectroscopy. In particular, the adsorption of water upon silica was investigated under controlled relative humidity environments. Furthermore, the collision and coagulation behaviour of silica particles with microdroplets of sulphuric acid was followed using both optical imaging and Raman spectroscopy. PMID:24803083

  3. Automated recognition of urinary microscopic solid particles.

    PubMed

    Almadhoun, Mohamed D; El-Halees, Alaa

    2014-03-01

    Urine analysis reveals the presence of many problems and diseases in the human body. Manual microscopic urine analysis is time-consuming, subjective to human observation and causes mistakes. Computer aided automatic microscopic analysis can help to overcome these problems. This paper introduces a comprehensive approach for automating procedures for detecting and recognition of microscopic urine particles. Samples of red blood cells (RBC), white blood cells (WBC), calcium oxalate, triple phosphate and other undefined images were used in experiments. Image processing functions and segmentation were applied, shape and textural features were extracted and five classifiers were tested to get the best results. Repeated experiments were done for adjusting factors to produce the best evaluation results. A good performance was achieved compared with many related works. PMID:24392883

  4. Global Evolution of Solid Matter in Turbulent Protoplanetry Disks. Part 1; Aerodynamics of Solid Particles

    NASA Technical Reports Server (NTRS)

    Stepinski, T. F.; Valageas, P.

    1996-01-01

    The problem of planetary system formation and its subsequent character can only be addressed by studying the global evolution of solid material entrained in gaseous protoplanetary disks. We start to investigate this problem by considering the space-time development of aerodynamic forces that cause solid particles to decouple from the gas. The aim of this work is to demonstrate that only the smallest particles are attached to the gas, or that the radial distribution of the solid matter has no momentary relation to the radial distribution of the gas. We present the illustrative example wherein a gaseous disk of 0.245 solar mass and angular momentum of 5.6 x 10(exp 52) g/sq cm/s is allowed to evolve due to turbulent viscosity characterized by either alpha = 10(exp -2) or alpha = 10(exp -3). The motion of solid particles suspended in a viscously evolving gaseous disk is calculated numerically for particles of different sizes. In addition we calculate the global evolution of single-sized, noncoagulating particles. We find that particles smaller than 0.1 cm move with the gas; larger particles have significant radial velocities relative to the gas. Particles larger than 0.1 cm but smaller than 10(exp 3) cm have inward radial velocities much larger than the gas, whereas particles larger than 10(exp 4) cm have inward velocities much smaller than the gas. A significant difference in the form of the radial distribution of solids and the gas develops with time. It is the radial distribution of solids, rather than the gas, that determines the character of an emerging planetary system.

  5. An amorphous solid state of biogenic secondary organic aerosol particles.

    PubMed

    Virtanen, Annele; Joutsensaari, Jorma; Koop, Thomas; Kannosto, Jonna; Yli-Pirilä, Pasi; Leskinen, Jani; Mäkelä, Jyrki M; Holopainen, Jarmo K; Pöschl, Ulrich; Kulmala, Markku; Worsnop, Douglas R; Laaksonen, Ari

    2010-10-14

    Secondary organic aerosol (SOA) particles are formed in the atmosphere from condensable oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs). On a global scale, biogenic VOCs account for about 90% of VOC emissions and of SOA formation (90 billion kilograms of carbon per year). SOA particles can scatter radiation and act as cloud condensation or ice nuclei, and thereby influence the Earth's radiation balance and climate. They consist of a myriad of different compounds with varying physicochemical properties, and little information is available on the phase state of SOA particles. Gas-particle partitioning models usually assume that SOA particles are liquid, but here we present experimental evidence that they can be solid under ambient conditions. We investigated biogenic SOA particles formed from oxidation products of VOCs in plant chamber experiments and in boreal forests within a few hours after atmospheric nucleation events. On the basis of observed particle bouncing in an aerosol impactor and of electron microscopy we conclude that biogenic SOA particles can adopt an amorphous solid-most probably glassy-state. This amorphous solid state should provoke a rethinking of SOA processes because it may influence the partitioning of semi-volatile compounds, reduce the rate of heterogeneous chemical reactions, affect the particles' ability to accommodate water and act as cloud condensation or ice nuclei, and change the atmospheric lifetime of the particles. Thus, the results of this study challenge traditional views of the kinetics and thermodynamics of SOA formation and transformation in the atmosphere and their implications for air quality and climate.

  6. An amorphous solid state of biogenic secondary organic aerosol particles.

    PubMed

    Virtanen, Annele; Joutsensaari, Jorma; Koop, Thomas; Kannosto, Jonna; Yli-Pirilä, Pasi; Leskinen, Jani; Mäkelä, Jyrki M; Holopainen, Jarmo K; Pöschl, Ulrich; Kulmala, Markku; Worsnop, Douglas R; Laaksonen, Ari

    2010-10-14

    Secondary organic aerosol (SOA) particles are formed in the atmosphere from condensable oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs). On a global scale, biogenic VOCs account for about 90% of VOC emissions and of SOA formation (90 billion kilograms of carbon per year). SOA particles can scatter radiation and act as cloud condensation or ice nuclei, and thereby influence the Earth's radiation balance and climate. They consist of a myriad of different compounds with varying physicochemical properties, and little information is available on the phase state of SOA particles. Gas-particle partitioning models usually assume that SOA particles are liquid, but here we present experimental evidence that they can be solid under ambient conditions. We investigated biogenic SOA particles formed from oxidation products of VOCs in plant chamber experiments and in boreal forests within a few hours after atmospheric nucleation events. On the basis of observed particle bouncing in an aerosol impactor and of electron microscopy we conclude that biogenic SOA particles can adopt an amorphous solid-most probably glassy-state. This amorphous solid state should provoke a rethinking of SOA processes because it may influence the partitioning of semi-volatile compounds, reduce the rate of heterogeneous chemical reactions, affect the particles' ability to accommodate water and act as cloud condensation or ice nuclei, and change the atmospheric lifetime of the particles. Thus, the results of this study challenge traditional views of the kinetics and thermodynamics of SOA formation and transformation in the atmosphere and their implications for air quality and climate. PMID:20944744

  7. Acceleration of solid particles by gaseous detonation products

    SciTech Connect

    Gavrilenko, T.P.; Grigoriev, V.V.; Zhdan, S.A.; Nikolaev, Y.A.; Boiko, V.M.; Papyrin, A.N.

    1986-11-01

    This investigation is concerned with a theoretical and experimental study of acceleration dynamics of spherically inert solid particles (100 ..mu..m nominal diameter) in flows of gaseous detonation products. The experiments were conducted in a detonation channel 1.5 m long with a 20 x 20 mm/sup 2/ cross section and one open end. Particle motion was observed with the method of multiexposure photographic recording and a laser stroboscopic light source. The character of velocity variation of individual particles inside and outside of the channel was investigated for different initial positions of particles. Under certain conditions the accelerated particles are destroyed. A mathematical model based on two-phase multivelocity continuum mechanics has been formulated to describe the detonation wave propagation, outflow of detonation products from the channel, and interaction between particles and a nonstationary flow of detonation products. The model includes chemical equilibrium of detonation products, particle acceleration, heat exchange between phases and channel walls, particle melting, and fragmentation of droplets if the Weber number exceeds some critical value. Particle destruction has been correlated with the initial position, diameter, and physical properties of particles. Comparison of computer and experimental results shows that the model satisfactorily describes acceleration, heating, and fragmentation of particles.

  8. Assessment of the effects of greywater reuse on gross solids movement in sewer systems.

    PubMed

    Penn, R; Schütze, M; Friedler, E

    2014-01-01

    Onsite greywater reuse (GWR) and installation of water-efficient toilets (WETs) reduce urban freshwater demand and thus enhance urban water use sustainability. Research on GWR and WETs has generally overlooked their potential effects on municipal sewer systems: GWR and WETs affect the flow regime in sewers, and consequently also influence gross solids transport. To asses these impacts, a gross solids transport model was developed. The model is based on approaches found in the literature. Hydrodynamic calculations of sewage flow were performed using the SIMBA6 simulator and then used for the gross solid movement models. Flow characteristics in the up- and downstream sections of the sewer network differ. Therefore different approaches were used to model solids movement in each of these two parts. Each model determines whether a solid moves as a result of a momentary sewage flow, and if it moves, calculation of its velocity is possible. The paper shows the adoption and implementation of two gross solids transport models using SIMBA6 and depicts the results of the effects of various GWR and WET scenarios on gross solids movement in sewers for a real case study in Israel.

  9. Solid-particle jet formation under shock-wave acceleration.

    PubMed

    Rodriguez, V; Saurel, R; Jourdan, G; Houas, L

    2013-12-01

    When solid particles are impulsively dispersed by a shock wave, they develop a spatial distribution which takes the form of particle jets whose selection mechanism is still unidentified. The aim of the present experimental work is to study particle dispersal with fingering effects in an original quasi-two-dimensional experiment facility in order to accurately extract information. Shock and blast waves are generated in the carrier gas at the center of a granular medium ring initially confined inside a Hele-Shaw cell and impulsively accelerated. With the present experimental setup, the particle jet formation is clearly observed. From fast flow visualizations, we notice, in all instances, that the jets are initially generated inside the particle ring and thereafter expelled outward. This point has not been observed in three-dimensional experiments. We highlight that the number of jets is unsteady and decreases with time. For a fixed configuration, considering the very early times following the initial acceleration, the jet size selection is independent of the particle diameter. Moreover, the influence of the initial overpressure and the material density on the particle jet formation have been studied. It is shown that the wave number of particle jets increases with the overpressure and with the decrease of the material density. The normalized number of jets as a function of the initial ring acceleration shows a power law valid for all studied configurations involving various initial pressure ratios, particle sizes, and particle materials. PMID:24483561

  10. Solid-particle jet formation under shock-wave acceleration.

    PubMed

    Rodriguez, V; Saurel, R; Jourdan, G; Houas, L

    2013-12-01

    When solid particles are impulsively dispersed by a shock wave, they develop a spatial distribution which takes the form of particle jets whose selection mechanism is still unidentified. The aim of the present experimental work is to study particle dispersal with fingering effects in an original quasi-two-dimensional experiment facility in order to accurately extract information. Shock and blast waves are generated in the carrier gas at the center of a granular medium ring initially confined inside a Hele-Shaw cell and impulsively accelerated. With the present experimental setup, the particle jet formation is clearly observed. From fast flow visualizations, we notice, in all instances, that the jets are initially generated inside the particle ring and thereafter expelled outward. This point has not been observed in three-dimensional experiments. We highlight that the number of jets is unsteady and decreases with time. For a fixed configuration, considering the very early times following the initial acceleration, the jet size selection is independent of the particle diameter. Moreover, the influence of the initial overpressure and the material density on the particle jet formation have been studied. It is shown that the wave number of particle jets increases with the overpressure and with the decrease of the material density. The normalized number of jets as a function of the initial ring acceleration shows a power law valid for all studied configurations involving various initial pressure ratios, particle sizes, and particle materials.

  11. Solid particle deposition during turbulent flow production operations

    SciTech Connect

    Escobedo, J.; Mansoori, G.A.

    1995-12-31

    The production and transportation of petroleum fluids could be severely affected by deposition of suspended particles (i.e., asphaltene, paraffin/wax, sand, and/or diamondoid) in the production wells and/or transfer pipelines. In many instances the amount of precipitation is rather large causing complete plugging of these conduits. Therefore, it is important to understand the behavior of suspended particles during flow conditions. In this paper the authors present an analysis of the diffusional effects on the rate of solid particle deposition during turbulent flow conditions (crude oil production generally falls within this regime). The turbulent boundary layer theory and the concepts of mass transfer have been utilized to calculate the particle deposition rates on the walls of the flowing conduit. The developed model accounts for the eddy and Brownian diffusivities as well as for inertial effects. The analysis presented in this paper shows that rates of solid-particle deposition (during crude oil production) on the walls of the flowing channel due solely to diffusional effects are small. It is also shown that deposition rates decrease with increasing particle size. However, when the process is momentum controlled (large particle sizes) higher deposition rates are expected.

  12. Actuated cilial layers regulate deposition of microscopic solid particles

    NASA Astrophysics Data System (ADS)

    Ghosh, Rajat; Buxton, Gavin A.; Berk Usta, O.; Balazs, Anna C.; Alexeev, Alexander

    2009-11-01

    We use computational modeling to examine the three-dimensional interactions between oscillating, synthetic cilia and microscopic solid particles in a fluid-filled microchannel. The synthetic cilia are elastic filaments that are tethered to a substrate and are actuated by a sinusoidal force, which is applied to their free ends. The cilia are arranged in a square pattern and a neutrally buoyant particle is initially located between these filaments. Our computational studies reveal that depending on frequency of the beating cilia, the particle can be either driven downwards toward the substrate or driven upwards and expelled into the fluid above the cilial layer. This behavior mimics the performance of biological cilia used by certain marine animals to extract suspended food particles. The findings uncover a new route for controlling the deposition of microscopic particles in microfluidic devices.

  13. Image preprocessing method for particle image velocimetry (PIV) image interrogation near a fluid-solid surface

    NASA Astrophysics Data System (ADS)

    Zhu, Yiding; Jia, Lichao; Bai, Ye; Yuan, Huijing; Lee, Cunbiao

    2014-11-01

    Accurate particle image velocimetry (PIV) measurements near the moving wall are a great challenge. The problem is compounded by the very large in-plane displacement on PIV images commonly encountered in measurements of the high speed flow. An improved image preprocessing method is presented in this paper. A wall detection technique is used first to qualify the wall position and the movement of the solid body. Virtual particle images are imposed in the solid region, of which the displacements are evaluated by the body movement. The estimation near the wall is then smoothed by data from both sides of the shear layer to reduce the large random uncertainties. Interrogations in the following iterative steps then converge to the correct results to provide accurate predictions for particle tracking velocimetries (PTV). Significant improvement is seen in Monte Carlo simulations and experimental tests such as measurements near a flapping flag or compressor plates. The algorithm also successfully extracted the small flow structures of the 2nd mode wave in the hypersonic boundary layer from PIV images with low signal-noise-ratios(SNR) when the traditional method was not successful.

  14. Kinetic behavior of solid particles in fluidized beds: Annual report

    SciTech Connect

    Kono, H.O.; Huang, C.C.

    1987-10-01

    This report summarizes technical accomplishments for the first year in a 3-year contract project for the Morgantown Energy Technology Center (METC) of the US Department of Energy (DOE) under contract number AC21-86MC23249. The objectives of the project are (1) to develop experimental techniques for measuring the forces of fluidized particles, and (2) to predict solid particle performance in fluidized beds using data analysis and mathematical modeling. During the first year, the fracture-sensitive tracer-particle method was developed and applied to investigate the effects of fluidized particle size, superficial gas velocity, bed height, bed diameter, and bed configuration on the kinetic behavior of solid particles in fluidized beds. Quantitative data and comprehensive information were obtained. A piezoresistive strain-gauge sensor and a PC data-acquisition system were also developed; these are being used to measure the force distribution in fluidized beds. The pressure fluctuation method will also be investigated in the near future. 12 refs., 24 figs., 2 tabs.

  15. A Refined Model for Solid Particle Rock Erosion

    NASA Astrophysics Data System (ADS)

    Momber, A. W.

    2016-02-01

    A procedure for the estimation of distribution parameters of a Weibull distribution model K 1 = f( K Ic 12/4 / σ C 23/4 ) for solid particle erosion, as recently suggested in Rock Mech Rock Eng, doi: 10.1007/s00603-014-0658-x, 2014, is derived. The procedure is based on examinations of elastic-plastically responding rocks (rhyolite, granite) and plastically responding rocks (limestone, schist). The types of response are quantified through SEM inspections of eroded surfaces. Quantitative numbers for the distribution parameter K 1 are calculated for 30 rock materials, which cover a wide range of mechanical properties. The ranking according to the parameter K 1 is related to qualitative rock classification schemes. A modified proposal for the erosion of schist due to solid particle impingement at normal incidence is introduced.

  16. Discrete particle simulations predicting mixing behavior of solid substrate particles in a rotating drum fermenter.

    PubMed

    Schutyser, M A; Padding, J T; Weber, F J; Briels, W J; Rinzema, A; Boom, R

    2001-12-20

    A soft-sphere discrete particle model was used to simulate mixing behavior of solid substrate particles in a slow rotating drum for solid-state fermentation. In this approach, forces acting on and subsequent motion of individual particles can be predicted. The (2D) simulations were qualitatively and quantitatively validated by mixing experiments using video and image analysis techniques. It was found that the simulations successfully predicted the mixing progress as a function of the degree of filling and size of the drum. It is shown that only relatively large, straight baffles perpendicular to the drum wall (67% of the drum radius) increase the mixing performance of the rotating drum. Considering the different aspects of mixing dealt with in this work, it is concluded that the soft sphere discrete particle model can serve as a valuable tool for investigating mixing of solid substrate particles. Finally, it is expected that this model may evolve into a potential tool for design and scale-up of mixed solid-state fermenters. PMID:11745144

  17. Passage of a charged particle through a thin solid film

    NASA Astrophysics Data System (ADS)

    Filippov, G. M.

    2015-07-01

    The inelastic collisions effect on the interaction of the projectile with a super thin solid film is considered. The wave nature of the particle and its transitions from delocalized to the strongly localized state defined many important properties of the interaction. As examples the effect of perforation the 1 nm carbon foil as well as the overwhelming passage through a thick porous layer are considered.

  18. Hydrodynamic Stability Analysis of Particle-Laden Solid Rocket Motors

    NASA Astrophysics Data System (ADS)

    Elliott, T. S.; Majdalani, J.

    2014-11-01

    Fluid-wall interactions within solid rocket motors can result in parietal vortex shedding giving rise to hydrodynamic instabilities, or unsteady waves, that translate into pressure oscillations. The oscillations can result in vibrations observed by the rocket, rocket subsystems, or payload, which can lead to changes in flight characteristics, design failure, or other undesirable effects. For many years particles have been embedded in solid rocket propellants with the understanding that their presence increases specific impulse and suppresses fluctuations in the flowfield. This study utilizes a two dimensional framework to understand and quantify the aforementioned two-phase flowfield inside a motor case with a cylindrical grain perforation. This is accomplished through the use of linearized Navier-Stokes equations with the Stokes drag equation and application of the biglobal ansatz. Obtaining the biglobal equations for analysis requires quantification of the mean flowfield within the solid rocket motor. To that end, the extended Taylor-Culick form will be utilized to represent the gaseous phase of the mean flowfield while the self-similar form will be employed for the particle phase. Advancing the mean flowfield by quantifying the particle mass concentration with a semi-analytical solution the finalized mean flowfield is combined with the biglobal equations resulting in a system of eight partial differential equations. This system is solved using an eigensolver within the framework yielding the entire spectrum of eigenvalues, frequency and growth rate components, at once. This work will detail the parametric analysis performed to demonstrate the stabilizing and destabilizing effects of particles within solid rocket combustion.

  19. Peristaltic pumping of solid particles immersed in a viscoelastic fluid

    NASA Astrophysics Data System (ADS)

    Chrispell, John; Fauci, Lisa

    2010-11-01

    Peristaltic pumping of fluid is a fundamental method of transport in many biological processes. In some instances, particles of appreciable size are transported along with the fluid, such as ovum transport in the oviduct or kidney stones in the ureter. In some of these biological settings, the fluid may be viscoelastic. In such a case, a nonlinear constitutive equation to describe the evolution of the viscoelastic contribution to the stress tensor must be included in the governing equations. Here we use an immersed boundary framework to study peristaltic transport of a macroscopic solid particle in a viscoelastic fluid governed by a Navier-Stokes/Oldroyd-B model. Numerical simulations of peristaltic pumping as a function of Weissenberg number are presented. We examine the spatial and temporal evolution of the polymer stress field, and also find that the viscoelasticity of the fluid does hamper the overall transport of the particle in the direction of the wave.

  20. Accelerated algorithm for computing the motion of solid particles suspended in fluid.

    PubMed

    Ding, E J

    2009-08-01

    A fast algorithm for computing the motion of solid particles suspended in fluid is presented. The motion of solid particles suspended in Stokes flow can be calculated without fully calculating the fluid motion. When the steady-state simulation is sufficient, this algorithm can greatly accelerate the simulation of solid particle suspension in Stokes flow.

  1. Transport coefficients of solid particles immersed in a viscous gas.

    PubMed

    Garzó, Vicente; Fullmer, William D; Hrenya, Christine M; Yin, Xiaolong

    2016-01-01

    Transport properties of a suspension of solid particles in a viscous gas are studied. The dissipation in such systems arises from two sources: inelasticity in particle collisions and viscous dissipation due to the effect of the gas phase on the particles. Here we consider a simplified case in which the mean relative velocity between the gas and solid phases is taken to be zero, such that "thermal drag" is the only remaining gas-solid interaction. Unlike the previous, more general, treatment of the drag force [Garzó et al., J. Fluid Mech. 712, 129 (2012)]JFLSA70022-112010.1017/jfm.2012.404, here we take into account contributions to the (scaled) transport coefficients η^{*} (shear viscosity), κ^{*} (thermal conductivity), and μ^{*} (Dufour-like coefficient) coming from the temperature dependence of the (dimensionless) friction coefficient γ^{*} characterizing the amplitude of the drag force. At moderate densities, the thermal drag model (which is based on the Enskog kinetic equation) is solved by means of the Chapman-Enskog method and the Navier-Stokes transport coefficients are determined in terms of the coefficient of restitution, the solid volume fraction, and the friction coefficient. The results indicate that the effect of the gas phase on η^{*} and μ^{*} is non-negligible (especially in the case of relatively dilute systems) while the form of κ^{*} is the same as the one obtained in the dry granular limit. Finally, as an application of these results, a linear stability analysis of the hydrodynamic equations is carried out to analyze the conditions for stability of the homogeneous cooling state. A comparison with direct numerical simulations shows a good agreement for conditions of practical interest. PMID:26871141

  2. Transport coefficients of solid particles immersed in a viscous gas

    NASA Astrophysics Data System (ADS)

    Garzó, Vicente; Fullmer, William D.; Hrenya, Christine M.; Yin, Xiaolong

    2016-01-01

    Transport properties of a suspension of solid particles in a viscous gas are studied. The dissipation in such systems arises from two sources: inelasticity in particle collisions and viscous dissipation due to the effect of the gas phase on the particles. Here we consider a simplified case in which the mean relative velocity between the gas and solid phases is taken to be zero, such that "thermal drag" is the only remaining gas-solid interaction. Unlike the previous, more general, treatment of the drag force [Garzó et al., J. Fluid Mech. 712, 129 (2012)], 10.1017/jfm.2012.404, here we take into account contributions to the (scaled) transport coefficients η* (shear viscosity), κ* (thermal conductivity), and μ* (Dufour-like coefficient) coming from the temperature dependence of the (dimensionless) friction coefficient γ* characterizing the amplitude of the drag force. At moderate densities, the thermal drag model (which is based on the Enskog kinetic equation) is solved by means of the Chapman-Enskog method and the Navier-Stokes transport coefficients are determined in terms of the coefficient of restitution, the solid volume fraction, and the friction coefficient. The results indicate that the effect of the gas phase on η* and μ* is non-negligible (especially in the case of relatively dilute systems) while the form of κ* is the same as the one obtained in the dry granular limit. Finally, as an application of these results, a linear stability analysis of the hydrodynamic equations is carried out to analyze the conditions for stability of the homogeneous cooling state. A comparison with direct numerical simulations shows a good agreement for conditions of practical interest.

  3. Transport coefficients of solid particles immersed in a viscous gas.

    PubMed

    Garzó, Vicente; Fullmer, William D; Hrenya, Christine M; Yin, Xiaolong

    2016-01-01

    Transport properties of a suspension of solid particles in a viscous gas are studied. The dissipation in such systems arises from two sources: inelasticity in particle collisions and viscous dissipation due to the effect of the gas phase on the particles. Here we consider a simplified case in which the mean relative velocity between the gas and solid phases is taken to be zero, such that "thermal drag" is the only remaining gas-solid interaction. Unlike the previous, more general, treatment of the drag force [Garzó et al., J. Fluid Mech. 712, 129 (2012)]JFLSA70022-112010.1017/jfm.2012.404, here we take into account contributions to the (scaled) transport coefficients η^{*} (shear viscosity), κ^{*} (thermal conductivity), and μ^{*} (Dufour-like coefficient) coming from the temperature dependence of the (dimensionless) friction coefficient γ^{*} characterizing the amplitude of the drag force. At moderate densities, the thermal drag model (which is based on the Enskog kinetic equation) is solved by means of the Chapman-Enskog method and the Navier-Stokes transport coefficients are determined in terms of the coefficient of restitution, the solid volume fraction, and the friction coefficient. The results indicate that the effect of the gas phase on η^{*} and μ^{*} is non-negligible (especially in the case of relatively dilute systems) while the form of κ^{*} is the same as the one obtained in the dry granular limit. Finally, as an application of these results, a linear stability analysis of the hydrodynamic equations is carried out to analyze the conditions for stability of the homogeneous cooling state. A comparison with direct numerical simulations shows a good agreement for conditions of practical interest.

  4. Acoustofluidics 15: streaming with sound waves interacting with solid particles.

    PubMed

    Sadhal, S S

    2012-08-01

    In Part 15 of the tutorial series "Acoustofluidics-exploiting ultrasonic standing waves forces and acoustic streaming in microfluidic systems for cell and particle manipulation," we examine the interaction of acoustic fields with solid particles. The main focus here is the interaction of standing waves with spherical particles leading to streaming, together with some discussion on one non-spherical case. We begin with the classical problem of a particle at the velocity antinode of a standing wave, and then treat the problem of a sphere at the velocity node, followed by the intermediate situation of a particle between nodes. Finally, we discuss the effect of deviation from sphericity which brings about interesting fluid mechanics. The entire Focus article is devoted to the analysis of the nonlinear fluid mechanics by singular perturbation methods, and the study of the streaming phenomenon that ensues from the nonlinear interaction. With the intention of being instructive material, this tutorial cannot by any means be considered 'complete and comprehensive' owing to the complexity of the class of problems being covered herein.

  5. Acoustofluidics 15: streaming with sound waves interacting with solid particles.

    PubMed

    Sadhal, S S

    2012-08-01

    In Part 15 of the tutorial series "Acoustofluidics-exploiting ultrasonic standing waves forces and acoustic streaming in microfluidic systems for cell and particle manipulation," we examine the interaction of acoustic fields with solid particles. The main focus here is the interaction of standing waves with spherical particles leading to streaming, together with some discussion on one non-spherical case. We begin with the classical problem of a particle at the velocity antinode of a standing wave, and then treat the problem of a sphere at the velocity node, followed by the intermediate situation of a particle between nodes. Finally, we discuss the effect of deviation from sphericity which brings about interesting fluid mechanics. The entire Focus article is devoted to the analysis of the nonlinear fluid mechanics by singular perturbation methods, and the study of the streaming phenomenon that ensues from the nonlinear interaction. With the intention of being instructive material, this tutorial cannot by any means be considered 'complete and comprehensive' owing to the complexity of the class of problems being covered herein. PMID:22744212

  6. Homogenous Surface Nucleation of Solid Polar Stratospheric Cloud Particles

    NASA Technical Reports Server (NTRS)

    Tabazadeh, A.; Hamill, P.; Salcedo, D.; Gore, Warren J. (Technical Monitor)

    2002-01-01

    A general surface nucleation rate theory is presented for the homogeneous freezing of crystalline germs on the surfaces of aqueous particles. While nucleation rates in a standard classical homogeneous freezing rate theory scale with volume, the rates in a surface-based theory scale with surface area. The theory is used to convert volume-based information on laboratory freezing rates (in units of cu cm, seconds) of nitric acid trihydrate (NAT) and nitric acid dihydrate (NAD) aerosols into surface-based values (in units of sq cm, seconds). We show that a surface-based model is capable of reproducing measured nucleation rates of NAT and NAD aerosols from concentrated aqueous HNO3 solutions in the temperature range of 165 to 205 K. Laboratory measured nucleation rates are used to derive free energies for NAT and NAD germ formation in the stratosphere. NAD germ free energies range from about 23 to 26 kcal mole, allowing for fast and efficient homogeneous NAD particle production in the stratosphere. However, NAT germ formation energies are large (greater than 26 kcal mole) enough to prevent efficient NAT particle production in the stratosphere. We show that the atmospheric NAD particle production rates based on the surface rate theory are roughly 2 orders of magnitude larger than those obtained from a standard volume-based rate theory. Atmospheric volume and surface production of NAD particles will nearly cease in the stratosphere when denitrification in the air exceeds 40 and 78%, respectively. We show that a surface-based (volume-based) homogeneous freezing rate theory gives particle production rates, which are (not) consistent with both laboratory and atmospheric data on the nucleation of solid polar stratospheric cloud particles.

  7. Spontaneous pairing and cooperative movements of micro-particles in a two dimensional plasma crystal

    SciTech Connect

    Zhdanov, S. K.; Couëdel, L.; Nosenko, V.; Thomas, H. M.; Morfill, G. E.

    2015-05-15

    In an argon plasma of 20 W rf discharge at a pressure of 1.38 Pa, a stable highly ordered monolayer of microparticles is suspended. We observe spontaneous particle pairing when suddenly reducing the gas pressure. Special types of dynamical activity, in particular, entanglement and cooperative movements of coupled particles have been registered. In the course of the experiment first appeared single vertical pairs of particles, in further they gradually accumulated causing melting of the entire crystal. To record pairing events, the particle suspension is side-view imaged using a vertically extended laser sheet. The long-lasting pre-melting phase assured the credible recording and identification of isolated particle pairs. The high monolayer charge density is crucial to explain the spontaneous pairing events observed in our experiments as the mutual repulsion between the particles comprising the monolayer make its vertical extend thicker.

  8. Fundamental studies of the solid-particle erosion of silicon

    NASA Technical Reports Server (NTRS)

    Routbort, J. L.; Scattergood, R. O.

    1982-01-01

    The predictions of the theories of solid-particle erosion of brittle materials are compared to experimental results of studies in which angular Al2O3 particles with mean diameters D of 23 to 270 microns are used to erode (111) surfaces of silicon single crystals at impact angles alpha from 20 to 90 deg and velocities v from 30 to 150 m/s. The description of the steady state erosion rate by a power law, delta W varies directly as (v sin alpha)(n)D(m) must be modified to include threshold and plasticity effects. Furthermore the velocity exponent n depends on D. Results using abrasives of different sizes mixed together can be explained using a logarithmic-normal distribution. The results of transient experiments can be used to explain the synergistic effects which are observed using a biomodal distribution of abrasives.

  9. Friction between footwear and floor covered with solid particles under dry and wet conditions.

    PubMed

    Li, Kai Way; Meng, Fanxing; Zhang, Wei

    2014-01-01

    Solid particles on the floor, both dry and wet, are common but their effects on the friction on the floor were seldom discussed in the literature. In this study, friction measurements were conducted to test the effects of particle size of solid contaminants on the friction coefficient on the floor under footwear, floor, and surface conditions. The results supported the hypothesis that particle size of solids affected the friction coefficient and the effects depended on footwear, floor, and surface conditions. On dry surfaces, solid particles resulted in friction loss when the Neolite footwear pad was used. On the other hand, solid particles provided additional friction when measured with the ethylene vinyl acetate (EVA) footwear pad. On wet surfaces, introducing solid particles made the floors more slip-resistant and such effects depended on particle size. This study provides information for better understanding of the mechanism of slipping when solid contaminants are present. PMID:24629869

  10. Friction between footwear and floor covered with solid particles under dry and wet conditions.

    PubMed

    Li, Kai Way; Meng, Fanxing; Zhang, Wei

    2014-01-01

    Solid particles on the floor, both dry and wet, are common but their effects on the friction on the floor were seldom discussed in the literature. In this study, friction measurements were conducted to test the effects of particle size of solid contaminants on the friction coefficient on the floor under footwear, floor, and surface conditions. The results supported the hypothesis that particle size of solids affected the friction coefficient and the effects depended on footwear, floor, and surface conditions. On dry surfaces, solid particles resulted in friction loss when the Neolite footwear pad was used. On the other hand, solid particles provided additional friction when measured with the ethylene vinyl acetate (EVA) footwear pad. On wet surfaces, introducing solid particles made the floors more slip-resistant and such effects depended on particle size. This study provides information for better understanding of the mechanism of slipping when solid contaminants are present.

  11. Models for solid-state transport: messenger RNA movement from nucleus to cytoplasm.

    PubMed

    Agutter, P S

    1994-09-01

    This paper explores the idea that mRNAs are transported between their transcription and processing sites in the nucleus, and their translation and degradation sites in the cytoplasm, by a 'solid-state' process. The underlying assumption is that negligible quantities of mRNA and of mRNA precursors are in solution in vivo. Therefore, mRNA transport cannot be considered as movement in the aqueous phase of the cell. The main lines of experimental evidence supporting this 'solid-state' concept are summarized and related controversies are outlined. Three possible models for a solid-state transport mechanism are discussed: a direct transfer model, with receptors organized analogously to the components of a multienzyme complex; a motor-driven model, analogous to synaptic vesicle transport in axons; and an assembly-driven model which assumes net movement along a fibril resulting from differential activities at the poles. Qualitative evaluation indicates that each of these models has characteristic advantages and disadvantages. The possibility that other nucleocytoplasmic transport processes might operate by solid-state mechanisms is briefly discussed.

  12. Compact solid-state neutral particle analyzer in current mode

    SciTech Connect

    Zhu, Y. B.; Bortolon, A.; Heidbrink, W. W.; Celle, S. L.; Roquemore, A. L.

    2012-10-15

    Solid state neutral particle analyzer (ssNPA) arrays are operated in current mode on the DIII-D tokamak and the National Spherical Torus Experiment (NSTX). Compared with conventional pulse-counting NPAs, current-mode operation sacrifices energy resolution to obtain economical, high-bandwidth, pitch-angle resolved measurements. With the success from a new three-channel near-vertical-view current mode ssNPA on DIII-D, the apertures on an existing array on NSTX were expanded to increase the particle influx. The sightlines of both arrays intersect heating beams, enabling both active and passive charge exchange measurements. The spatial resolution at beam intersection is typically 5 cm on both devices. Directly deposited ultra-thin foils on the detector surface block stray photons below the energy of 1 keV and also set low energy threshold about 25 keV for deuterium particle detection. Oscillations in neutral flux produced by high frequency magnetohydrodynamics (MHD) instabilities are readily detected.

  13. Overview of solid particle LV seeding techniques used at UTRC

    NASA Technical Reports Server (NTRS)

    Patrick, W. P.

    1985-01-01

    Due to the failure of existing seeders to meet the stringent specifications required for benchmark experiments in high pressure, high temperature, rapidly accelerating flowfields, an effort is made to improve an existing solid particle seeder. The goal is to produce a more monodisperse seed from the 0.3 micro alumina powder with more than 99 percent of the particles in the submicron range while maintaining a high seeding rate. Coiled-wire inserts are installed within the ends of the nitrogen injection lines in the primary seeder to produce swirling conical jets to vigorously agitate the seed bed. A secondary swirler, constructed from a 25 cm length of 3.8 cm ID steel pipe having threaded end caps, is connected to the output line of the primary seeder. The seeded nitrogen from the primary seeder is injected tangentially at near sonic velocity into the secondary swirler 9.4 cm above its base. Independently controlled auxiliary nitrogen used to increase the swirl in the secondary chamber is also injected tangentially 2.5 cm below the seeded nitrogen lines. Large seed particles are collected by bleeds in the swirler cap and directed overboard. The remaining seeded nitrogen is collected on the center line of the secondary swirler and ducted to the rig.

  14. Compact solid-state neutral particle analyzer in current mode.

    PubMed

    Zhu, Y B; Bortolon, A; Heidbrink, W W; Celle, S L; Roquemore, A L

    2012-10-01

    Solid state neutral particle analyzer (ssNPA) arrays are operated in current mode on the DIII-D tokamak and the National Spherical Torus Experiment (NSTX). Compared with conventional pulse-counting NPAs, current-mode operation sacrifices energy resolution to obtain economical, high-bandwidth, pitch-angle resolved measurements. With the success from a new three-channel near-vertical-view current mode ssNPA on DIII-D, the apertures on an existing array on NSTX were expanded to increase the particle influx. The sightlines of both arrays intersect heating beams, enabling both active and passive charge exchange measurements. The spatial resolution at beam intersection is typically 5 cm on both devices. Directly deposited ultra-thin foils on the detector surface block stray photons below the energy of 1 keV and also set low energy threshold about 25 keV for deuterium particle detection. Oscillations in neutral flux produced by high frequency magnetohydrodynamics (MHD) instabilities are readily detected.

  15. Compact solid-state neutral particle analyzer in current modea)

    NASA Astrophysics Data System (ADS)

    Zhu, Y. B.; Bortolon, A.; Heidbrink, W. W.; Celle, S. L.; Roquemore, A. L.

    2012-10-01

    Solid state neutral particle analyzer (ssNPA) arrays are operated in current mode on the DIII-D tokamak and the National Spherical Torus Experiment (NSTX). Compared with conventional pulse-counting NPAs, current-mode operation sacrifices energy resolution to obtain economical, high-bandwidth, pitch-angle resolved measurements. With the success from a new three-channel near-vertical-view current mode ssNPA on DIII-D, the apertures on an existing array on NSTX were expanded to increase the particle influx. The sightlines of both arrays intersect heating beams, enabling both active and passive charge exchange measurements. The spatial resolution at beam intersection is typically 5 cm on both devices. Directly deposited ultra-thin foils on the detector surface block stray photons below the energy of 1 keV and also set low energy threshold about 25 keV for deuterium particle detection. Oscillations in neutral flux produced by high frequency magnetohydrodynamics (MHD) instabilities are readily detected.

  16. Air distribution and size changes in the remediated zone after air sparging for soil particle movement.

    PubMed

    Tsai, Yih-Jin

    2008-10-30

    In an unconsolidated porous medium, soil particles can be mobilized by physical perturbation. In model systems of fluids flowing over spherical particles attached to flat surfaces, the hydrodynamic shear force depends on the fluid viscosity, particle radius, and flow velocity. Soil particles can be reasonably expected to be transported by flowing water during air sparging when the particle-size distribution does not fit the densest possible particle arrangement. If soil particles are transported during air sparging, then the distribution of the porosity and reservoir permeability will change. The remediated zone changes because of the changes in soil characteristics. This study applied some mathematical models to elucidate the mobilization process of soil particles during in situ air sparging. The changes in the characteristics of the soil and the swept volume of injected air during air sparging were also investigated. The results demonstrated that particle movement reduced the radius of influence (ROI) and the swept volume of injected air. In this case study, the maximum reducing rates in ROI and the swept volume were 24% and 26% for the zone where the gas saturation exceeded 10%.

  17. Evaluation of Potential Climate Change Impacts on Particle Movement in Open Channel Flow

    NASA Astrophysics Data System (ADS)

    Lin, E.; Tsai, C.

    2014-12-01

    It is important to develop a forecast model to predict the trajectory of sediment particles when extreme flow events occur. In extreme flow environments, the stochastic jump diffusion particle tracking model (SJD-PTM) can be used to model the movement of sediment particles in response to extreme events. This proposed SJD-PTM can be separated into three main parts — a drift motion, a turbulence term and a jump term due to random occurrences of extreme flow events. The study is intended to modify the jump term, which models the abrupt changes of particle position in the extreme flow environments. The frequency of extreme flow occurrences might change due to many uncertain factors such as climate change. The study attempts to use the concept of the logistic regression and the parameter of odds ratio, namely the trend magnitude to investigate the frequency change of extreme flow event occurrences and its impact on sediment particle movement. With the SJD-PTM, the ensemble mean and variance of particle trajectory can be quantified via simulations. The results show that by taking the effect of the trend magnitude into consideration, the particle position and its uncertainty may undergo a significant increase. Such findings will have many important implications to the environmental and hydraulic engineering design and planning. For instance, when the frequency of the occurrence of flow events with higher extremity increases, particles can travel further and faster downstream. It is observed that flow events with higher extremity can induce a higher degree of entrainment and particle resuspension, and consequently more significant bed and bank erosion.

  18. Determination of Solid Particle Concentration at coal Transshipment site

    NASA Astrophysics Data System (ADS)

    Siliņš, K.; Žandeckis, A.; Valtere, S.

    2009-01-01

    Coal handling and grinding processes are associated with significant particulate matter emissions into the atmosphere. This problem is particularly urgent when a coal-processing company is located in or nearby a densely populated city. To quantitatively evaluate concentrations generated into the atmosphere according to the standardized methodology, it is necessary to make extensive measurements using an automatic real-time, infrared dust and aerosol monitor. Before the experiments, the impact of particulate matter on human health and the environment was explored, six solid particle concentration detection methods and best available techniques for particulate matter emission prevention was described. During this study field measurements were carried out at on the territory of a coal transshipment company. Using the solid particle concentration detection system Dust Detective kit, concentration monitoring of total particulate matter (TSP), PM10 and PM2.5 was carried out. The equipment was located 6 m above ground and 120 m away from the emission source - coal crushing and handling site. TSP monitoring was carried out during four diurnal, PM10 - during 17 diunral and PM2.5 - during 12 days. After comparison of results with concentration values set in normative documents of Latvia and EU, it was found out that average 17 diurnal day concentration values of PM10 exceeded normative values for nine times. PM2.5 daily average concentrations of 12 days exceeded for four times exceeded the value of 25 μg/m3, which is mentioned in Directive 2008/50/EC of EU. After analysis of wind behaviour impact on the concentration values it is now understood that if wind comes from the dust emission source to the measurement system, the increase in wind speed increases particle concentration as all particles in the air and those raised from coal piles are driven towards the equipment. If wind comes from the opposite direction, the decrease of wind velocity results in an increase of

  19. Methods of conveying fluids and methods of sublimating solid particles

    DOEpatents

    Turner, Terry D; Wilding, Bruce M

    2013-10-01

    A heat exchanger and associated methods for sublimating solid particles therein, for conveying fluids therethrough, or both. The heat exchanger includes a chamber and a porous member having a porous wall having pores in communication with the chamber and with an interior of the porous member. A first fluid is conveyed into the porous member while a second fluid is conveyed into the porous member through the porous wall. The second fluid may form a positive flow boundary layer along the porous wall to reduce or eliminate substantial contact between the first fluid and the interior of the porous wall. The combined first and second fluids are conveyed out of the porous member. Additionally, the first fluid and the second fluid may each be conveyed into the porous member at different temperatures and may exit the porous member at substantially the same temperature.

  20. Solid State Neutral Particle Analyzer Array on NSTX

    SciTech Connect

    K. Shinohara; D.S. Darrow; A.L. Roquemore; S.S. Medley; F.E. Cecil

    2004-05-13

    A Solid State Neutral Particle Analyzer (SSNPA) array has been installed on the National Spherical Torus Experiment (NSTX). The array consists of four chords viewing through a common vacuum flange. The tangency radii of the viewing chords are 60, 90, 100, and 120 cm. They view across the three co-injection neutral beam lines (deuterium, 80 keV (typ.) with tangency radii 48.7, 59.2, and 69.4 cm) on NSTX and detect co-going energetic ions. A silicon photodiode used was calibrated by using a mono-energetic deuteron beam source. Deuterons with energy above 40 keV can be detected with the present setup. The degradation of the performance was also investigated. Lead shots and epoxy are used for neutron shielding to reduce handling any hazardous heavy metal. This method also enables us to make an arbitrary shape to be fit into the complex flight tube.

  1. A new dimension in retrograde flow: centripetal movement of engulfed particles.

    PubMed Central

    Caspi, A; Yeger, O; Grosheva, I; Bershadsky, A D; Elbaum, M

    2001-01-01

    Centripetal motion of surface-adherent particles is a classic experimental system for studying surface dynamics on a eukaryotic cell. To investigate bead migration over the entire cell surface, we have developed an experimental assay using multinuclear giant fibroblasts, which provide expanded length scales and an unambiguous frame of reference. Beads coated by adhesion ligands concanavalin A or fibronectin are placed in specific locations on the cell using optical tweezers, and their subsequent motion is tracked over time. The adhesion, as well as velocity and directionality of their movement, expose distinct regions of the cytoplasm and membrane. Beads placed on the peripheral lamella initiate centripetal motion, whereas beads placed on the central part of the cell attach to a stationary cortex and do not move. Careful examination by complementary three-dimensional methods shows that the motion of a bead placed on the cell periphery takes place after engulfment into the cytoplasm, whereas stationary beads, placed near the cell center, are not engulfed. These results demonstrate that centripetal motion of adhering particles may occur inside as well as outside the cell. Inhibition of actomyosin activity is used to explore requirements for engulfment and aspects of the bead movement. Centripetal movement of adherent particles seems to depend on mechanisms distinct from those driving overall cell contractility. PMID:11566772

  2. Particle engineering in pharmaceutical solids processing: surface energy considerations.

    PubMed

    Williams, Daryl R

    2015-01-01

    During the past 10 years particle engineering in the pharmaceutical industry has become a topic of increasing importance. Engineers and pharmacists need to understand and control a range of key unit manufacturing operations such as milling, granulation, crystallisation, powder mixing and dry powder inhaled drugs which can be very challenging. It has now become very clear that in many of these particle processing operations, the surface energy of the starting, intermediate or final products is a key factor in understanding the processing operation and or the final product performance. This review will consider the surface energy and surface energy heterogeneity of crystalline solids, methods for the measurement of surface energy, effects of milling on powder surface energy, adhesion and cohesion on powder mixtures, crystal habits and surface energy, surface energy and powder granulation processes, performance of DPI systems and finally crystallisation conditions and surface energy. This review will conclude that the importance of surface energy as a significant factor in understanding the performance of many particulate pharmaceutical products and processes has now been clearly established. It is still nevertheless, work in progress both in terms of development of methods and establishing the limits for when surface energy is the key variable of relevance.

  3. Surface composition of solid-rocket exhausted aluminum oxide particles

    NASA Technical Reports Server (NTRS)

    Cofer, Wesley R., III; Winstead, Edward L.; Key, Lawrence E.

    1989-01-01

    Particulate samples of aluminum oxide were collected on Teflon filters from the exhaust plume of the Space Shuttle (STS-61A, October 30, 1985) over the altitude interval 4.6-7.6 km immediately after launch. These particles were analyzed using SEM, energy-dispersive X-ray analysis, electron spectroscopy for chemical analysis, X-ray fluorescent spectroscopy, and conventional wet-chemical techniques. The samples were 0.6-1.0 percent surface-chlorided (chlorided meaning predominantly aluminum chlorides and oxychlorides, possibly including other adsorbed forms of chloride) by weight. This level of chloriding is about one-third of the amount determined previously from laboratory-prepared alumina and surface site samples of solid-rocket-produced alumina (SRPA) after both had been exposed to moist HCl vapor at temperatures down to ambient. This level is equivalent to previous laboratory results with samples exposed to moist HCl at temperatures above the boiling point of water. It is suggested that the present lower chloriding levels, determined for samples from a 'dry' Shuttle exhaust cloud, underscore the importance of a liquid water/hydrochloric acid phase in governing the extent of surface chloriding of SRPA. The reduced chloriding is not trivial with respect to potential physical/chemical modification of the SRPA particle surfaces and their corresponding interaction with the atmosphere.

  4. Particle engineering in pharmaceutical solids processing: surface energy considerations.

    PubMed

    Williams, Daryl R

    2015-01-01

    During the past 10 years particle engineering in the pharmaceutical industry has become a topic of increasing importance. Engineers and pharmacists need to understand and control a range of key unit manufacturing operations such as milling, granulation, crystallisation, powder mixing and dry powder inhaled drugs which can be very challenging. It has now become very clear that in many of these particle processing operations, the surface energy of the starting, intermediate or final products is a key factor in understanding the processing operation and or the final product performance. This review will consider the surface energy and surface energy heterogeneity of crystalline solids, methods for the measurement of surface energy, effects of milling on powder surface energy, adhesion and cohesion on powder mixtures, crystal habits and surface energy, surface energy and powder granulation processes, performance of DPI systems and finally crystallisation conditions and surface energy. This review will conclude that the importance of surface energy as a significant factor in understanding the performance of many particulate pharmaceutical products and processes has now been clearly established. It is still nevertheless, work in progress both in terms of development of methods and establishing the limits for when surface energy is the key variable of relevance. PMID:25876912

  5. Launch Vehicle Performance with Solid Particle Feed Systems for Atomic Propellants

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    1998-01-01

    An analysis of launch vehicle Gross Liftoff Weight (GLOW) using high energy density atomic propellants with solid particle feed systems was conducted. The analyses covered several propellant combinations, including atoms of aluminum (Al), boron (B). carbon (C), and hydrogen (H) stored in a solid cryogenic particle, with a cryogenic liquid as the carrier fluid. Several different weight percents (wt%) for the liquid carrier were investigated and the gross lift off weight (GLOW) of the vehicles using the solid particle feed systems were compared with a conventional 02/H2 propellant vehicle. The potential benefits and effects of feed systems using solid particles in a liquid cryogenic fluid are discussed.

  6. Solid Hydrogen Experiments for Atomic Propellants: Particle Formation Energy and Imaging Analyses

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2002-01-01

    This paper presents particle formation energy balances and detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium during the Phase II testing in 2001. Solid particles of hydrogen were frozen in liquid helium and observed with a video camera. The solid hydrogen particle sizes and the total mass of hydrogen particles were estimated. The particle formation efficiency is also estimated. Particle sizes from the Phase I testing in 1999 and the Phase II testing in 2001 were similar. Though the 2001 testing created similar particles sizes, many new particle formation phenomena were observed. These experiment image analyses are one of the first steps toward visually characterizing these particles and it allows designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

  7. PARTICLE TRACKING ANALYSIS & ANIMATIONS DEPICTING MOVEMENT OF THE CARBON TETRACHLORIDE PLUME REPORT

    SciTech Connect

    MCMAHON, W.J.; ROHAY, V.J.

    2006-11-02

    The purpose of the hydraulic particle tracking animation files is to show where carbon tetrachloride that reached groundwater from the known discharge facilities would have been likely to travel fin the groundwater, and from where carbon tetrachloride presently observed in the aquifer likely would have started. These analyses support the 200-PW-1 Operable Unit activity to identify sources of carbon tetrachloride currently observed in groundwater or locations where carbon tetrachloride may have entered the groundwater. The animation files show travel paths (both forward and backward in time) for hypothetical particles of carbon tetrachloride carried in the groundwater. The travel paths represent the movement of the carbon tetrachloride at the average groundwater velocity. The particles only represent an estimation of where the carbon tetrachloride would be expected to be (or have come from) and do not indicate or imply what the concentration in the groundwater would be.

  8. Fundamental equations of a mixture of gas and small spherical solid particles from simple kinetic theory.

    NASA Technical Reports Server (NTRS)

    Pai, S. I.

    1973-01-01

    The fundamental equations of a mixture of a gas and pseudofluid of small spherical solid particles are derived from the Boltzmann equation of two-fluid theory. The distribution function of the gas molecules is defined in the same manner as in the ordinary kinetic theory of gases, but the distribution function for the solid particles is different from that of the gas molecules, because it is necessary to take into account the different size and physical properties of solid particles. In the proposed simple kinetic theory, two additional parameters are introduced: one is the radius of the spheres and the other is the instantaneous temperature of the solid particles in the distribution of the solid particles. The Boltzmann equation for each species of the mixture is formally written, and the transfer equations of these Boltzmann equations are derived and compared to the well-known fundamental equations of the mixture of a gas and small solid particles from continuum theory. The equations obtained reveal some insight into various terms in the fundamental equations. For instance, the partial pressure of the pseudofluid of solid particles is not negligible if the volume fraction of solid particles is not negligible as in the case of lunar ash flow.

  9. Parvovirus particles and movement in the cellular cytoplasm and effects of the cytoskeleton.

    PubMed

    Lyi, Sangbom Michael; Tan, Min Jie Alvin; Parrish, Colin R

    2014-05-01

    Cell infection by parvoviruses requires that capsids be delivered from outside the cell to the cytoplasm, followed by genome trafficking to the nucleus. Here we microinject capsids into cells that lack receptors and followed their movements within the cell over time. In general the capsids remained close to the positions where they were injected, and most particles did not move to the vicinity of or enter the nucleus. When 70 kDa-dextran was injected along with the capsids that did not enter the nucleus in significant amounts. Capsids conjugated to peptides containing the SV40 large T-antigen nuclear localization signal remained in the cytoplasm, although bovine serum albumen conjugated to the same peptide entered the nucleus rapidly. No effects of disruption of microfilaments, intermediate filaments, or microtubules on the distribution of the capsids were observed. These results suggest that movement of intact capsids within cells is primarily associated with passive processes.

  10. Parvovirus particles and movement in the cellular cytoplasm and effects of the cytoskeleton

    SciTech Connect

    Lyi, Sangbom Michael; Tan, Min Jie Alvin Parrish, Colin R.

    2014-05-15

    Cell infection by parvoviruses requires that capsids be delivered from outside the cell to the cytoplasm, followed by genome trafficking to the nucleus. Here we microinject capsids into cells that lack receptors and followed their movements within the cell over time. In general the capsids remained close to the positions where they were injected, and most particles did not move to the vicinity of or enter the nucleus. When 70 kDa-dextran was injected along with the capsids that did not enter the nucleus in significant amounts. Capsids conjugated to peptides containing the SV40 large T-antigen nuclear localization signal remained in the cytoplasm, although bovine serum albumen conjugated to the same peptide entered the nucleus rapidly. No effects of disruption of microfilaments, intermediate filaments, or microtubules on the distribution of the capsids were observed. These results suggest that movement of intact capsids within cells is primarily associated with passive processes.

  11. Development of three-dimensional integrated microchannel-electrode system to understand the particles' movement with electrokinetics.

    PubMed

    Yao, J; Obara, H; Sapkota, A; Takei, M

    2016-03-01

    An optical transparent 3-D Integrated Microchannel-Electrode System (3-DIMES) has been developed to understand the particles' movement with electrokinetics in the microchannel. In this system, 40 multilayered electrodes are embedded at the 2 opposite sides along the 5 square cross-sections of the microchannel by using Micro Electro-Mechanical Systems technology in order to achieve the optical transparency at the other 2 opposite sides. The concept of the 3-DIMES is that the particles are driven by electrokinetic forces which are dielectrophoretic force, thermal buoyancy, electrothermal force, and electroosmotic force in a three-dimensional scope by selecting the excitation multilayered electrodes. As a first step to understand the particles' movement driven by electrokinetic forces in high conductive fluid (phosphate buffer saline (PBS)) with the 3-DIMES, the velocities of particles' movement with one pair of the electrodes are measured three dimensionally by Particle Image Velocimetry technique in PBS; meanwhile, low conductive fluid (deionized water) is used as a reference. Then, the particles' movement driven by the electrokinetic forces is discussed theoretically to estimate dominant forces exerting on the particles. Finally, from the theoretical estimation, the particles' movement mainly results from the dominant forces which are thermal buoyancy and electrothermal force, while the velocity vortex formed at the 2 edges of the electrodes is because of the electroosmotic force. The conclusions suggest that the 3-DIMES with PBS as high conductive fluid helps to understand the three-dimensional advantageous flow structures for cell manipulation in biomedical applications. PMID:27042247

  12. High-Speed Transport of Fluid Drops and Solid Particles via Surface Acoustic Waves

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Sherrit, Stewart; Badescu, Mircea; Lih, Shyh-shiuh

    2012-01-01

    A compact sampling tool mechanism that can operate at various temperatures, and transport and sieve particle sizes of powdered cuttings and soil grains with no moving parts, has been created using traveling surface acoustic waves (SAWs) that are emitted by an inter-digital transducer (IDT). The generated waves are driven at about 10 MHz, and it causes powder to move towards the IDT at high speed with different speeds for different sizes of particles, which enables these particles to be sieved. This design is based on the use of SAWs and their propelling effect on powder particles and fluids along the path of the waves. Generally, SAWs are elastic waves propagating in a shallow layer of about one wavelength beneath the surface of a solid substrate. To generate SAWs, a piezoelectric plate is used that is made of LiNbO3 crystal cut along the x-axis with rotation of 127.8 along the y-axis. On this plate are printed pairs of fingerlike electrodes in the form of a grating that are activated by subjecting the gap between the electrodes to electric field. This configuration of a surface wave transmitter is called IDT. The IDT that was used consists of 20 pairs of fingers with 0.4-mm spacing, a total length of 12.5 mm. The surface wave is produced by the nature of piezoelectric material to contract or expand when subjected to an electric field. Driving the IDT to generate wave at high amplitudes provides an actuation mechanism where the surface particles move elliptically, pulling powder particles on the surface toward the wavesource and pushing liquids in the opposite direction. This behavior allows the innovation to separate large particles and fluids that are mixed. Fluids are removed at speed (7.5 to 15 cm/s), enabling this innovation of acting as a bladeless wiper for raindrops. For the windshield design, the electrodes could be made transparent so that they do not disturb the driver or pilot. Multiple IDTs can be synchronized to transport water or powder over larger

  13. Low energy charged particles interacting with amorphous solid water layers.

    PubMed

    Horowitz, Yonatan; Asscher, Micha

    2012-04-01

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 μA) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 ± 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  14. Low energy charged particles interacting with amorphous solid water layers

    NASA Astrophysics Data System (ADS)

    Horowitz, Yonatan; Asscher, Micha

    2012-04-01

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 μA) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 ± 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  15. Lidar measurements of solid rocket propellant fire particle plumes.

    PubMed

    Brown, David M; Brown, Andrea M; Willitsford, Adam H; Dinello-Fass, Ryan; Airola, Marc B; Siegrist, Karen M; Thomas, Michael E; Chang, Yale

    2016-06-10

    This paper presents the first, to our knowledge, direct measurement of aerosol produced by an aluminized solid rocket propellant (SRP) fire on the ground. Such fires produce aluminum oxide particles small enough to loft high into the atmosphere and disperse over a wide area. These results can be applied to spacecraft launchpad accidents that expose spacecraft to such fires; during these fires, there is concern that some of the plutonium from the spacecraft power system will be carried with the aerosols. Accident-related lofting of this material would be the net result of many contributing processes that are currently being evaluated. To resolve the complexity of fire processes, a self-consistent model of the ground-level and upper-level parts of the plume was determined by merging ground-level optical measurements of the fire with lidar measurements of the aerosol plume at height during a series of SRP fire tests that simulated propellant fire accident scenarios. On the basis of the measurements and model results, the Johns Hopkins University Applied Physics Laboratory (JHU/APL) team was able to estimate the amount of aluminum oxide (alumina) lofted into the atmosphere above the fire. The quantification of this ratio is critical for a complete understanding of accident scenarios, because contaminants are transported through the plume. This paper provides an estimate for the mass of alumina lofted into the air. PMID:27409023

  16. Lidar measurements of solid rocket propellant fire particle plumes.

    PubMed

    Brown, David M; Brown, Andrea M; Willitsford, Adam H; Dinello-Fass, Ryan; Airola, Marc B; Siegrist, Karen M; Thomas, Michael E; Chang, Yale

    2016-06-10

    This paper presents the first, to our knowledge, direct measurement of aerosol produced by an aluminized solid rocket propellant (SRP) fire on the ground. Such fires produce aluminum oxide particles small enough to loft high into the atmosphere and disperse over a wide area. These results can be applied to spacecraft launchpad accidents that expose spacecraft to such fires; during these fires, there is concern that some of the plutonium from the spacecraft power system will be carried with the aerosols. Accident-related lofting of this material would be the net result of many contributing processes that are currently being evaluated. To resolve the complexity of fire processes, a self-consistent model of the ground-level and upper-level parts of the plume was determined by merging ground-level optical measurements of the fire with lidar measurements of the aerosol plume at height during a series of SRP fire tests that simulated propellant fire accident scenarios. On the basis of the measurements and model results, the Johns Hopkins University Applied Physics Laboratory (JHU/APL) team was able to estimate the amount of aluminum oxide (alumina) lofted into the atmosphere above the fire. The quantification of this ratio is critical for a complete understanding of accident scenarios, because contaminants are transported through the plume. This paper provides an estimate for the mass of alumina lofted into the air.

  17. Interactions of energetic particles and clusters with solids

    SciTech Connect

    Averback, R.S.; Hsieh, Horngming . Dept. of Materials Science and Engineering); Diaz de la Rubia, T. ); Benedek, R. )

    1990-12-01

    Ion beams are being applied for surface modifications of materials in a variety of different ways: ion implantation, ion beam mixing, sputtering, and particle or cluster beam-assisted deposition. Fundamental to all of these processes is the deposition of a large amount of energy, generally some keV's, in a localized area. This can lead to the production of defects, atomic mixing, disordering and in some cases, amorphization. Recent results of molecular dynamics computer simulations of energetic displacement cascades in Cu and Ni with energies up to 5 keV suggest that thermal spikes play an important role in these processes. Specifically, it will be shown that many aspects of defect production, atomic mixing and cascade collapse'' can be understood as a consequence of local melting of the cascade core. Included in this discussion will be the possible role of electron-phonon coupling in thermal spike dynamics. The interaction of energetic clusters of atoms with solid surfaces has also been studied by molecular dynamics simulations. this process is of interest because a large amount of energy can be deposited in a small region and possibly without creating point defects in the substrate or implanting cluster atoms. The simulations reveal that the dynamics of the collision process are strongly dependent on cluster size and energy. Different regimes where defect production, local melting and plastic flow dominate will be discussed. 43 refs., 7 figs.

  18. Low energy charged particles interacting with amorphous solid water layers

    SciTech Connect

    Horowitz, Yonatan; Asscher, Micha

    2012-04-07

    The interaction of charged particles with condensed water films has been studied extensively in recent years due to its importance in biological systems, ecology as well as interstellar processes. We have studied low energy electrons (3-25 eV) and positive argon ions (55 eV) charging effects on amorphous solid water (ASW) and ice films, 120-1080 ML thick, deposited on ruthenium single crystal under ultrahigh vacuum conditions. Charging the ASW films by both electrons and positive argon ions has been measured using a Kelvin probe for contact potential difference (CPD) detection and found to obey plate capacitor physics. The incoming electrons kinetic energy has defined the maximum measurable CPD values by retarding further impinging electrons. L-defects (shallow traps) are suggested to be populated by the penetrating electrons and stabilize them. Low energy electron transmission measurements (currents of 0.4-1.5 {mu}A) have shown that the maximal and stable CPD values were obtained only after a relatively slow change has been completed within the ASW structure. Once the film has been stabilized, the spontaneous discharge was measured over a period of several hours at 103 {+-} 2 K. Finally, UV laser photo-emission study of the charged films has suggested that the negative charges tend to reside primarily at the ASW-vacuum interface, in good agreement with the known behavior of charged water clusters.

  19. Solid Hydrogen Experiments for Atomic Propellants: Particle Formation, Imaging, Observations, and Analyses

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2005-01-01

    This report presents particle formation observations and detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Hydrogen was frozen into particles in liquid helium, and observed with a video camera. The solid hydrogen particle sizes and the total mass of hydrogen particles were estimated. These newly analyzed data are from the test series held on February 28, 2001. Particle sizes from previous testing in 1999 and the testing in 2001 were similar. Though the 2001 testing created similar particles sizes, many new particle formation phenomena were observed: microparticles and delayed particle formation. These experiment image analyses are some of the first steps toward visually characterizing these particles, and they allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

  20. Directed movement of latex particles in the gynoecia of three species of flowering plants.

    PubMed

    Sanders, L C; Lord, E M

    1989-03-24

    The secretory matrix of the stylar-transmitting tract of angiosperms has been characterized as a nutrient medium for the growth of pollen tubes, acting to guide tubes to the ovules. When nonliving particles (latex beads) were artificially introduced onto the transmitting tracts of styles of Hemerocallis flava, Raphanus raphanistrum, and Vicia faba, they were translocated to the ovary at rates similar to those of pollen tubes. Direct observations were made on the movement of individual beads along the secretory epidermis in the style and ovary of Vicia faba. The transmitting tract may play an active role in extending tube tips to their destination in the ovary. PMID:17847262

  1. Simulation of drop movement over an inclined surface using smoothed particle hydrodynamics.

    PubMed

    Das, Arup K; Das, Prasanta K

    2009-10-01

    Smoothed particle hydrodynamics (SPH) is used to numerically simulate the movement of drops down an inclined plane. Diffuse interfaces have been assumed for tracking the motion of the contact line. The asymmetric shape of the three-dimensional drop and the variation of contact angle along its periphery can be calculated using the simulation. During the motion of a liquid drop down an inclined plane, an internal circulation of liquid particles is observed due to gravitational pull which causes periodic change in the drop shape. The critical angle of inclination required for the inception of drop motion is also evaluated for different fluids as a function of drop volume. The numerical predictions exhibit a good agreement with the published experimental results.

  2. Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

    PubMed Central

    Pflieger, Rachel; Chave, Tony; Virot, Matthieu; Nikitenko, Sergey I.

    2014-01-01

    The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO2 powder in pure water yields stable colloids of plutonium due to both effects. PMID:24747272

  3. Simplified fluid-structure coupled analysis of particle movement for designing of microfluidic cell sorter.

    PubMed

    Takagi, Yuto; Kotev, Vladimir; Yano, Ken'ich

    2015-01-01

    Recently, methods of the separation and selection of cells using a microfluidic device are receiving a lot of attention as the latest technology and those devices are called microfluidic cell sorter. Those methods have many advantages compared to conventional methods. There are a lot of researches on the microfluidic cell sorting but there isn't the automated design method of this device in spite of the necessary. To achieve the automated design of the microfluidic cell sorter, the analysis of the movement of cells in the microfluidic device and optimum design of the microfluidic cell sorter corresponding to kind of various cells are required. In the former case, the fluid-structure interaction analysis of fluid and cell movement is needed. However, it is very complex and needs a lot of computational time. Therefore, we focused on this problem in the fluid-structure interaction analysis for designing the microfluidic cell sorter. We assume cell is a sphere particle and propose the simplified fluid-structure coupled analysis which combines the CFD analysis with the motion equation of a sphere particle.

  4. Proposed method for controlling turbid particles in solid-phase bioluminescent toxicity measurement.

    PubMed

    Yeo, Seul-Ki; Park, Jun-Boum; Ahn, Joo-Sung; Han, Young-Soo

    2015-06-01

    In the recent half century, numerous methods have been developed to assess ecological toxicity. However, the presence of solid-particle turbidity sometimes causes such tests to end with questionable results. Many researchers focused on controlling this arbitrary turbidity effect when using the Microtox® solid-phase toxicity system, but there is not yet a standard method. In this study, we examined four solid-phase sample test methods recommended in the Microtox® manual, or proposed from the literature, and compared the existing methods with our proposed method (centrifuged basic solid-phase test, c-BSPT). Four existing methods use the following strategies to control turbid particles: complete separation of liquid and solid using 0.45-μm filtration before contacting solid samples and bacteria, natural settlement, moderate separation of large particles using coarser pore size filtration, and exclusion of light loss in the toxicity calculation caused by turbidity after full disturbance of samples. Our proposed method uses moderate centrifugation to separate out the heavier soil particles from the lighter bacteria after direct contact between them. Among the solid-phase methods tested, in which the bacteria and solid particles were in direct contact (i.e., the three existing methods and the newly proposed one, c-BSPT), no single method could be recommended as optimal for samples over a range of turbidity. Instead, a simple screening strategy for selecting a sample-dependent solid-phase test method was suggested, depending on the turbidity of the solid suspension. The results of this study highlight the importance of considering solid particles, and the necessity for optimal selection of test method to reduce errors in the measurement of solid-phase toxicity.

  5. A novel method for tracing the movement of multiple individual soil particles under rainfall conditions using florescent videography.

    NASA Astrophysics Data System (ADS)

    Hardy, Robert; Pates, Jackie; Quinton, John

    2016-04-01

    The importance of developing new techniques to study soil movement cannot be underestimated especially those that integrate new technology. Currently there are limited empirical data available about the movement of individual soil particles, particularly high quality time-resolved data. Here we present a new technique which allows multiple individual soil particles to be traced in real time under simulated rainfall conditions. The technique utilises fluorescent videography in combination with a fluorescent soil tracer, which is based on natural particles. The system has been successfully used on particles greater than ~130 micrometres diameter. The technique uses HD video shot at 50 frames per second, providing extremely high temporal (0.02 s) and spatial resolution (sub-millimetre) of a particle's location without the need to perturb the system. Once the tracer has been filmed then the images are processed and analysed using a particle analysis and visualisation toolkit written in python. The toolkit enables the creation of 2 and 3-D time-resolved graphs showing the location of 1 or more particles. Quantitative numerical analysis of a pathway (or collection of pathways) is also possible, allowing parameters such as particle speed and displacement to be assessed. Filming the particles removes the need to destructively sample material and has many side-benefits, reducing the time, money and effort expended in the collection, transport and laboratory analysis of soils, while delivering data in a digital form which is perfect for modern computer-driven analysis techniques. There are many potential applications for the technique. High resolution empirical data on how soil particles move could be used to create, parameterise and evaluate soil movement models, particularly those that use the movement of individual particles. As data can be collected while rainfall is occurring it may offer the ability to study systems under dynamic conditions(rather than rainfall of a

  6. Food-grade Pickering emulsions stabilised with solid lipid particles.

    PubMed

    Pawlik, Aleksandra; Kurukji, Daniel; Norton, Ian; Spyropoulos, Fotis

    2016-06-15

    Aqueous dispersions of tripalmitin particles (with a minimum size of 130 nm) were produced, via a hot sonication method, with and without the addition of food-grade emulsifiers. Depending on their relative size and chemistry, the emulsifiers altered the properties of the fat particles (e.g. crystal form, dispersion state and surface properties) by two proposed mechanisms. Firstly, emulsifiers modify the rate and/or extent of polymorphic transitions, resulting in the formation of fat crystals with a range of polarities. Secondly, the adsorption of emulsifiers at the particle interface modifies crystal surface properties. Such emulsifier-modified fat particles were then used to stabilise emulsions. As the behaviour of these particles was predisposed by the kind of emulsifier employed for their manufacture, the resulting particles showed different preferences to which of the emulsion phases (oil or water) became the continuous one. The polarity of the fat particles decreased as follows: Whey Protein Isolate > Soy Lecithin > Soy Lecithin + Tween 20 > Tween 20 > Polyglycerol Polyricinoleate > no emulsifier. Consequently, particles stabilised with WPI formed oil-in-water emulsions (O/W); particles stabilised solely with lecithin produced a highly unstable W/O emulsion; and particles stabilised with a mixture of lecithin and Tween 20 gave a stable W/O emulsion with drop size up to 30 μm. Coalescence stable, oil-continuous emulsions (W/O) with drop sizes between 5 and 15 μm were produced when the tripalmitin particles were stabilised with solely with Tween 20, solely with polyglycerol polyricinoleate, or with no emulsifier at all. It is proposed that the stability of the latter three emulsions was additionally enhanced by sintering of fat particles at the oil-water interface, providing a mechanical barrier against coalescence. PMID:27198879

  7. Universal Features of the Fluid to Solid Transition for Attractive Colloidal Particles

    NASA Technical Reports Server (NTRS)

    Cipelletti, L.; Prasad, V.; Dinsmore, A.; Segre, P. N.; Weitz, D. A.; Trappe, V.

    2002-01-01

    Attractive colloidal particles can exhibit a fluid to solid phase transition if the magnitude of the attractive interaction is sufficiently large, if the volume fraction is sufficiently high, and if the applied stress is sufficiently small. The nature of this fluid to solid transition is similar for many different colloid systems, and for many different forms of interaction. The jamming phase transition captures the common features of these fluid to solid translations, by unifying the behavior as a function of the particle volume fraction, the energy of interparticle attractions, and the applied stress. This paper describes the applicability of the jamming state diagram, and highlights those regions where the fluid to solid transition is still poorly understood. It also presents new data for gelation of colloidal particles with an attractive depletion interaction, providing more insight into the origin of the fluid to solid transition.

  8. Behavior of ceramic particles at the solid-liquid metal interface in metal matrix composites

    NASA Technical Reports Server (NTRS)

    Stefanescu, D. M.; Dhindaw, B. K.; Kacar, S. A.; Moitra, A.

    1988-01-01

    Directional solidification results were obtained in order to investigate particle behavior at the solid-liquid interface in Al-2 pct Mg (cellular interface) and Al-6.1 pct Ni (eutectic interface) alloys. It is found that particles can be entrapped in the solid if adequate solidification rates and temperature gradients are used. Model results showed critical velocity values slightly higher than those obtained experimentally.

  9. Oil-in-oil emulsions stabilised solely by solid particles.

    PubMed

    Binks, Bernard P; Tyowua, Andrew T

    2016-01-21

    A brief review of the stabilisation of emulsions of two immiscible oils is given. We then describe the use of fumed silica particles coated with either hydrocarbon or fluorocarbon groups in acting as sole stabilisers of emulsions of various vegetable oils with linear silicone oils (PDMS) of different viscosity. Transitional phase inversion of emulsions, containing equal volumes of the two oils, from silicone-in-vegetable (S/V) to vegetable-in-silicone (V/S) occurs upon increasing the hydrophobicity of the particles. Close to inversion, emulsions are stable to coalescence and gravity-induced separation for at least one year. Increasing the viscosity of the silicone oil enables stable S/V emulsions to be prepared even with relatively hydrophilic particles. Predictions of emulsion type from calculated contact angles of a silica particle at the oil-oil interface are in agreement with experiment provided a small polar contribution to the surface energy of the oils is included. We also show that stable multiple emulsions of V/S/V can be prepared in a two-step procedure using two particle types of different hydrophobicity. At fixed particle concentration, catastrophic phase inversion of emulsions from V/S to S/V can be effected by increasing the volume fraction of vegetable oil. Finally, in the case of sunflower oil + 20 cS PDMS, the study is extended to particles other than silica which differ in chemical type, particle size and particle shape. Consistent with the above findings, we find that only sufficiently hydrophobic particles (clay, zinc oxide, silicone, calcium carbonate) can act as efficient V/S emulsion stabilisers.

  10. Bioremediation of solid TNT particles in a soil slurry reactor: Mass transfer considerations

    SciTech Connect

    Gilcrease, P.C.; Murphy, V.G.; Reardon, K.F.

    1996-12-31

    The bioreduction of solid TNT by a Pseudomonas fluorescens strain was investigated in a stirred tank reactor. Experiments in which TNT beads were the only solids present indicated that the biodegradation mechanism is dissolution followed by degradation in bulk solution. Dissolution may limit the overall rate, in which case degradation can be enhanced through increased agitation. Since soil slurries may contain high concentrations of solids other than TNT, Teflon chips were added to investigate two separate effects on TNT dissolution in slurries. First, Teflon solids increase the viscosity of the slurry, resulting in lower solid-liquid mass transfer coefficients. Second, the agitated Teflon slurry can grind or comminute TNT particles, creating additional surface area for mass transfer. Enhanced dissolution rates were observed for TNT beads in a Teflon slurry at higher agitator speeds. This suggests that the biodegradation of solid TNT nuggets in a soil slurry bioreactor may be enhanced under conditions that promote particle attrition.

  11. Applications for Large Solid Scintillator Detectors in Neutrino and Particle Astrophysics

    NASA Astrophysics Data System (ADS)

    Bross, Alan D.

    2012-08-01

    Applications for solid scintillator have expanded tremendously over the last decade due, in part, to the development of extruded plastic scintillator. In addition, the rapid development of new solid-state photo detectors over the last few years has further expanded the possibilities for this type of detector. This talk will review the state-of-the-art in solid scintillator detectors focusing on applications in neutrino physics, and will present some new possibilities for inorganic scintillator use in particle astrophysics experiments.

  12. Nuclear particle detection using a track-recording solid

    NASA Technical Reports Server (NTRS)

    Weber, M.; Weber, D.

    1984-01-01

    The design of the nuclear particle detector located in Purdue University's Get Away Special package which was flown aboard STS-7 is detailed. The experiment consisted of a stack of particle-detecting polymer sheets. The sheets show positive results of tracks throughout the block. A slide of each sheet was made for further analysis. Recommendations for similar experiments performed in the future are discussed.

  13. A solid-phase mechanism of shock-wave formation of dust particles of heavy metals

    NASA Astrophysics Data System (ADS)

    Lin, E. E.; Mikhailov, A. L.; Khvorostin, V. N.

    2016-08-01

    The possibility of formation of dust particles in solid as a result of shock-wave destruction of the initial crystalline material structure and subsequent coalescence of atomic clusters (nanoparticles), which leads to the aggregation of mesocrystalline particles (grains) in the shocked layer, is discussed.

  14. A rocket-borne energy spectrometer using multiple solid-state detectors for particle identification

    NASA Technical Reports Server (NTRS)

    Fries, K. L.; Smith, L. G.; Voss, H. D.

    1979-01-01

    A rocket-borne experiment using energy spectrometers that allows particle identification by the use of multiple solid-state detectors is described. The instrumentation provides information regarding the energy spectrum, pitch-angle distribution, and the type of energetic particles present in the ionosphere. Particle identification was accomplished by considering detector loss mechanisms and their effects on various types of particles. Solid state detectors with gold and aluminum surfaces of several thicknesses were used. The ratios of measured energies for the various detectors were compared against known relationships during ground-based analysis. Pitch-angle information was obtained by using detectors with small geometrical factors mounted with several look angles. Particle flux was recorded as a function of rocket azimuth angle. By considering the rocket azimuth, the rocket precession, and the location of the detectors on the rocket, the pitched angle of the incident particles was derived.

  15. Growth of solid and hollow gold particles through the thermal annealing of nanoscale patterned thin films

    SciTech Connect

    Lin, Junhao; He, Weidong; Vilayur Ganapathy, Subramanian; Peppernick, Samuel J.; Wang, Bin; Palepu, Sandeep; Remec, Miroslav; Hess, Wayne P.; Hmelo, Anthony B.; Pantelides, Sokrates T.; Dickerson, James

    2013-11-27

    Through thermally annealing well-arrayed, circular, nanoscale thin films of gold, deposited onto [111] silicon/silicon dioxide substrates, both solid and hollow gold particles of different morphologies with controllable sizes were obtained. The thin film could form individual particle or clusters of particles by tuning the diameter of it. Hollow gold particles were featured by their large size whose diameter was larger than 500 nm and confirmed by a cross-section view. Hollow gold particles show greater plasmonic field enhancement under photoemission electron microscopy. Potential growth mechanisms for these structures are explored

  16. Nonisothermal particle modeling of municipal solid waste combustion with heavy metal vaporization

    SciTech Connect

    Mazza, G.; Falcoz, Q.; Gauthier, D.; Flamant, G.; Soria, J.

    2010-12-15

    A particulate model was developed for municipal solid-waste incineration in a fluidized bed combining solid-waste-particle combustion and heavy metal vaporization from the burning particles. Based on a simpler, isothermal version presented previously, this model combines an asymptotic-combustion model for carbonaceous-solid combustion and a shrinking-core model to describe the heavy metal vaporization phenomenon, in which the particle is now considered nonisothermal. A parametric study is presented that shows the influence of temperature on the global metal-vaporization process. The simulation results are compared to experimental data obtained with a lab-scale fluid bed incinerator and to the results of the simpler isothermal model. It is shown that conduction in the particle strongly affects the variation of the vaporization rate with time and that the present version of the model well fits both the shape of the plots and the maximum heavy metal vaporization rates for all bed temperatures. (author)

  17. Two-phase flow of solid hydrogen particles and liquid helium

    NASA Astrophysics Data System (ADS)

    Xu, J.; Rouelle, A.; Smith, K. M.; Celik, D.; Hussaini, M. Y.; Van Sciver, S. W.

    2004-06-01

    Atomic hydrogen propellant feed systems may require transporting solid hydrogen particles containing atomic species from storage tanks to the engines using liquid helium as the carrier fluid. In this paper, a three-dimensional two-phase mixture model, along with the standard k- ɛ mixture turbulence model is employed to study the turbulent mixing of the fluid-particle slurry system. Numerical results show that turbulent flow is required to keep the hydrogen particles in suspension, which otherwise form a sliding layer of particles on top of the helium layer. Hydrogen particle concentration profiles in the slurry system are functions of particle size, flow velocity, and influx volume fraction of hydrogen particles. Particle dispersion at different Stokes numbers, different Kolmogorov length scales, and different time scales are discussed.

  18. Acoustic separation of submicron solid particles in air.

    PubMed

    Imani, Ramin J; Robert, Etienne

    2015-12-01

    The use of ultrasound to continuously separate submicron particles suspended in air is investigated in a rectangular channel with adjustable height. An electrostatic transducer is used to generate a standing wave in the 50-80 kHz frequency range and the particles experience forces within the acoustic field causing them to concentrate at the pressure nodes. To assess the effect of several key design parameters on the separation efficiency, a simple method based on light scattering is implemented to provide information on the particle concentrations as a function of position in the channel. The images acquired are processed to yield a separation efficiency metric that is used to evaluate the effect of acoustic, flow and geometrical parameters. The results show that, in qualitative agreement with theoretical models, the maximum separation efficiency increases with the pressure amplitude of the sound wave. The separation efficiency is also linearly proportional to the standing wave frequency, when it is varied between 50-80 kHz. On the other hand, the effect of the average fluid velocity is less pronounced than expected, suggesting that in our channel separation is not limited by the interaction length between the acoustic field and the suspended particles. The effect of the parallelism of the reflector relative to the transducer is also investigated.

  19. Lattice-Boltzmann methods for suspensions of solid particles

    NASA Astrophysics Data System (ADS)

    Ladd, Anthony J. C.

    2015-09-01

    In this paper, dedicated to Prof. Jean-Pierre Hansen, I will summarise the development of lattice-Boltzmann methods for simulating the dynamics of colloidal suspensions. I will describe the main ideas and subsequent improvements, and place them in the wider context of particle-based methods for fluid dynamics.

  20. Suspension of solid particles in an aerospace plane's slush hydrogen tanks

    NASA Astrophysics Data System (ADS)

    Navickas, J.; Cady, E. C.; Ditter, J. L.

    As part of an effort to develop the necessary computational tools to model the dynamics of slush hydrogen in tanks for the flight environment for an aerospace type vehicle, the FLOW-3D program was modified to model solid particles in a liquid. The program was modified to include the flow characteristics of densely particles by introducing an effective mixture viscosity and an effective drag coefficient as a function of the solid fraction. The displacement of particles initially at rest on a flat surface, and then disturbed by passing a liquid jet up through the particle layer, was simulated using the modified code. An experimental apparatus emulating this was also constructed with spherical polyethylene beads in a water-alcohol mixture simulating a slush hydrogen mixture. Comparisons between experimental and numerical results indicate that improved models of densely packed particle regions are needed.

  1. Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy.

    PubMed

    Verch, Andreas; Pfaff, Marina; de Jonge, Niels

    2015-06-30

    Gold nanoparticles were observed to move at a liquid/solid interface 3 orders of magnitude slower than expected for the movement in a bulk liquid by Brownian motion. The nanoscale movement was studied with scanning transmission electron microscopy (STEM) using a liquid enclosure consisting of microchips with silicon nitride windows. The experiments involved a variation of the electron dose, the coating of the nanoparticles, the surface charge of the enclosing membrane, the viscosity, and the liquid thickness. The observed slow movement was not a result of hydrodynamic hindrance near a wall but instead explained by the presence of a layer of ordered liquid exhibiting a viscosity 5 orders of magnitude larger than a bulk liquid. The increased viscosity presumably led to a dramatic slowdown of the movement. The layer was formed as a result of the surface charge of the silicon nitride windows. The exceptionally slow motion is a crucial aspect of electron microscopy of specimens in liquid, enabling a direct observation of the movement and agglomeration of nanoscale objects in liquid.

  2. Determination of kinematic indices corresponding to a solid particle on a flat oscillating surface

    NASA Astrophysics Data System (ADS)

    Mosnegutu, E.; Nedeff, V.; Bontas, O.; Barsan, N.; Chitimus, D.; Rusu, D.

    2016-08-01

    This articles presents a mathematical analysis having as purpose the understanding of the behaviour of a solid particle on a flat oscillating surface. The starting point of the analysis is the initial identification of the actions direction of forces on a solid particle placed on a flat oscillating surface, in a 3D reference system. Following the distribution of forces, for different specific cases of the behaviour of the solid particle, the general equations of kinematic indices could be determined, ks and kj. Due to achieving the 3D distribution model of forces acting on a solid particle, a new kinematic index could be determined, index corresponding to the sideways moving of the solid particle kl. Moreover, a series of graphical representations have been carried out, having as purpose the emphasis of the variation mode of the newly determined kinematic indices, as following: friction coefficient µ = 0.4; the angle of the inertial force to the flat oscillating surface, Φ = 0 - 180° the angle between the projection of the inertial force on XOY plane and OX axis, α2, = 0 - 80o. After analyzing the graphical representations for the new calculation forms of the kinematic indices, kl variation has the same rate and trend as kj. If angle α2 = 0o, the variation curve of ki index coincides with the variation curve of kj, and as we increase the value of angle α2, the variation curve of kl index moves away from the kj curve.

  3. Internal damping due to dislocation movements induced by thermal expansion mismatch between matrix and particles in metal matrix composites. [Al/SiC

    SciTech Connect

    Girand, C.; Lormand, G.; Fougeres, R.; Vincent, A. )

    1993-05-01

    In metal matrix composites (MMCs), the mechanical 1 of the reinforcement-matrix interface is an important parameter because it governs the load transfer from matrix to particles, from which the mechanical properties of these materials are derived. Therefore, it would be useful to set out an experimental method able to characterize the interface and the adjacent matrix behaviors. Thus, a study has been undertaken by means of internal damping (I.D.) measurements, which are well known to be very sensitive for studying irreversible displacements at the atomic scale. More especially, this investigation is based on the fact that, during cooling of MMC's, stress concentrations originating from differences in coefficients of thermal expansion (C.T.E.) of matrix and particles should induce dislocation movements in the matrix surrounding the reinforcement; that is, local microplastic strains occur. Therefore, during I.D. measurements vs temperature these movements should contribute to MMCs I.D. in a process similar to those involved around first order phase transitions in solids. The aim of this paper is to present, in the case of Al/SiC particulate composites, new developments of this approach that has previously led to promising results in the case of Al-Si alloys.

  4. Ice nucleus activity measurements of solid rocket motor exhaust particles

    NASA Technical Reports Server (NTRS)

    Keller, V. W. (Compiler)

    1986-01-01

    The ice Nucleus activity of exhaust particles generated from combustion of Space Shuttle propellant in small rocket motors has been measured. The activity at -20 C was substantially lower than that of aerosols generated by unpressurized combustion of propellant samples in previous studies. The activity decays rapidly with time and is decreased further in the presence of moist air. These tests corroborate the low effectivity ice nucleus measurement results obtained in the exhaust ground cloud of the Space Shuttle. Such low ice nucleus activity implies that Space Shuttle induced inadvertent weather modification via an ice phase process is extremely unlikely.

  5. Mirror fluid method for numerical simulation of sedimentation of a solid particle in a Newtonian fluid.

    PubMed

    Yang, Chao; Mao, Zai-Sha

    2005-03-01

    The mirror fluid method is proposed for simulating solid-fluid two-phase flow. The whole computational domain is modeled as an Eulerian one for the fluid with a Lagrangian subdomain embedded in it. The boundary condition is enforced implicitly on solid-fluid surface segments by mirror relations. Thus, the total flow is solved in the one domain, in which the solid particle region is replaced with the virtual flow as the mirror image of outside flow. The mirror fluid method is implemented to compute the motion of a rigid spherical or elliptic particle in a Newtonian fluid for the purpose of method validation. The control volume formulation with the SIMPLE algorithm incorporated is used to solve the governing equations on a staggered grid in a two-dimensional coordinate system. A number of numerical experiments on falling particles are performed and the computational results are in good agreement with the reported experimental data.

  6. Stiff particles on highly compliant solid substrates: adhesion or wetting?

    NASA Astrophysics Data System (ADS)

    Jensen, Katharine; Dufresne, Eric

    2015-03-01

    The classic theories of contact mechanics with deformable materials account only for the competition between adhesion energy and elasticity. However, for compliant materials, solid surface tension also plays an important role in resisting shape change, and may significantly modify the physics of contact with soft matter. We report experiments bringing small, stiff spheres into adhesive contact with compliant silicone substrates. We observe the quasi-static deformation of the substrate in two sticky situations: with zero applied force, where the spheres are allowed to settle to an equilibrium position, and during forced withdrawal from contact starting from from an initial condition of zero displacement. In both cases, we map the profiles of the deformed silicone surface, and compare to capillary and elastic theories. The similarities - and differences - between our experimental measurements and the classic theories point to a crossover form a capillary-dominated near field response close to the contact line to an elastic-dominated response in the far field.

  7. Multiple cell hits by particle tracks in solid tissues

    NASA Astrophysics Data System (ADS)

    Todd, P.

    1992-08-01

    Relative Biological Effectiveness (RBE) and Quality Factor (Q) at extreme values of Linear Energy Transfer (LET) have been determined on the basis of experiments with single-cell systems and specific tissue responses. In typical single cell systems, each heavy particle (Ar or Fe) passes through a single cell or no cell. In tissue end-point experiments each heavy particle passes through several cells, and the LET can exceed 200 keV/μm in every cell. In most laboratory animal tissue systems, however, only a small portion of the hit cells are capable of expressing the end-point of interest to the investigator, such as cell killing, mutation or carcinogenesis. The following question must therefore be addressed: Do RBE's and Q factors derived from single-cell experiments properly account for the increased probability of multiple-cell damage by HZE tracks? A model is offered in which measured radiation effects and known tissue properties are combined to estimate the value of a multiplier of damage effectiveness on the basis of number of cells at risk, p3n, per track containing a hit cell, where n is the number of cells per track, based on tissue and organ geometry, and p3 is the probability that a cell in the track is capable of expressing the experimental end-point.

  8. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    PubMed

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-21

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization.

  9. Numerical investigation of jamming of solid particles in a straight pipe

    SciTech Connect

    Sun, Y.; Vinogradov, O.

    1996-12-31

    The flow of fluids containing solid particles is numerically simulated in order to determine the critical parameters of the system leading to a jam. Two parameters are varied: the volumetric density of solid particles and the velocity of fluid flow. The energy dissipation in the system is due to dry friction losses and collisions. The results presented are based on the mathematical models of granular materials treated as multibody systems with variable topology. The fluid flow is considered to be potential. It is shown that jamming strongly depends on the volumetric density of particles and fluid velocity. The results of numerical experiments are in qualitative agreement with physical experiments of flow of spherical particles in a pipe.

  10. An analysis of particle track effects on solid mammalian tissues

    NASA Technical Reports Server (NTRS)

    Todd, P.; Clarkson, T. W. (Principal Investigator)

    1992-01-01

    Relative biological effectiveness (RBE) and quality factor (Q) at extreme values of linear energy transfer (LET) have been determined on the basis of experiments with single-cell systems and specific tissue responses. In typical single-cell systems, each heavy particle (Ar or Fe) passes through a single cell or no cell. In experiments on animal tissues, however, each heavy particle passes through several cells, and the LET can exceed 200 keV micrometers-1 in every cell. In most laboratory animal tissue systems, however, only a small portion of the hit cells are capable of expressing the end-point being measured, such as cell killing, mutation or carcinogenesis. The following question was therefore addressed: do RBEs and Q factors derived from single-cell experiments properly account for the damage at high LET when multiple cells are hit by HZE tracks? A review is offered in which measured radiation effects and known tissue properties are combined to estimate on the one hand, the number of cells at risk, p3n, per track, where n is the number of cells per track based on tissue and organ geometry, and p3 is the probability that a cell in the track is capable of expressing the experimental end-point. On the other hand, the tissue and single-cell responses are compared by determining the ratio RBE in tissue/RBE in corresponding single cells. Experimental data from the literature indicate that tissue RBEs at very high LET (Fe and Ar ions) are higher than corresponding single-cell RBEs, especially in tissues in which p3n is high.

  11. Innovative Method Using Magnetic Particle Tracking to Measure Solids Circulation in a Spouted Bed

    SciTech Connect

    Patterson, Ms. Emily; Halow, John; Daw, C Stuart

    2010-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  12. Particle size distribution measurements in a subscale motor for the Ariane 5 solid rocket booster

    NASA Astrophysics Data System (ADS)

    Traineau, J. C.; Kuentzmann, P.; Prevost, M.; Tarrin, P.; Delfour, A.

    1992-07-01

    An experimental determination of the combustion-chamber aluminum oxide particle-size distribution for the Ariane 5 Solid Rocket Booster is carried out. A subscale motor using a helium injection technique for quenching the reaction products is designed, manufactured and tested. A 30 percent helium-mass flow rate injection close to the head-end of the combustion chamber is found to give an exhaust aluminum oxide particle-size distribution representative of the combustion chamber distribution. A laser light-scattering technique and a particle-capturing technique are used and large particles found with both sizing techniques. A stretched particle size volume distribution with particle diameters ranging from 1 to 120 microns, with a maximum around 45 microns is demonstrated.

  13. Gold nanoparticle translocation dynamics and electrical detection of single particle diffusion using solid-state nanopores.

    PubMed

    Goyal, Gaurav; Freedman, Kevin J; Kim, Min Jun

    2013-09-01

    This paper describes the use of gold nanoparticles to study particle translocation dynamics through silicon nitride solid-state nanopores. Gold nanoparticles were dispersed in 20 mM KCl solution containing nonionic surfactant Triton X-100 and their translocation was studied at different applied voltages. The use of low electrolyte concentration resulted in current enhancement upon particle translocation. The counterion cloud around the nanoparticles is proposed to be the reason for current enhancement phenomena because associated counterion cloud is believed to increase the ion density inside the pore during particle translocation. Further, single particle diffusion events were also recorded at 0 mV voltage bias and 0 pA background ionic current with high signal-to-noise ratio as the particles moved down their concentration gradient. The ability of nanopore sensors to detect single particle diffusion can be extended to field-free analysis of biomolecules in their native state and at or near physiological salt concentrations.

  14. System design of a 1 MW north-facing, solid particle receiver

    SciTech Connect

    Christian, J.; Ho, C.

    2015-05-01

    Falling solid particle receivers (SPR) utilize small particles as a heat collecting medium within a cavity receiver structure. The components required to operate an SPR include the receiver (to heat the particles), bottom hopper (to catch the falling particles), particle lift elevator (to lift particles back to the top of the receiver), top hopper (to store particles before being dropped through the receiver), and ducting. In addition to the required components, there are additional features needed for an experimental system. These features include: a support structure to house all components, calibration panel to measure incident radiation, cooling loops, and sensors (flux gages, thermocouples, pressure gages). Each of these components had to be designed to withstand temperatures ranging from ambient to 700 °C. Thermal stresses from thermal expansion become a key factor in these types of high temperature systems. The SPR will be housing ~3000 kg of solid particles. The final system will be tested at the National Solar Thermal Test Facility in Albuquerque, NM.

  15. System design of a 1 MW north-facing, solid particle receiver

    DOE PAGESBeta

    Christian, J.; Ho, C.

    2015-05-01

    Falling solid particle receivers (SPR) utilize small particles as a heat collecting medium within a cavity receiver structure. The components required to operate an SPR include the receiver (to heat the particles), bottom hopper (to catch the falling particles), particle lift elevator (to lift particles back to the top of the receiver), top hopper (to store particles before being dropped through the receiver), and ducting. In addition to the required components, there are additional features needed for an experimental system. These features include: a support structure to house all components, calibration panel to measure incident radiation, cooling loops, and sensorsmore » (flux gages, thermocouples, pressure gages). Each of these components had to be designed to withstand temperatures ranging from ambient to 700 °C. Thermal stresses from thermal expansion become a key factor in these types of high temperature systems. The SPR will be housing ~3000 kg of solid particles. The final system will be tested at the National Solar Thermal Test Facility in Albuquerque, NM.« less

  16. Motion of a distant solid particle in a shear flow along a porous slab

    NASA Astrophysics Data System (ADS)

    Khabthani, S.; Sellier, A.; Feuillebois, F.

    2013-12-01

    The motion of a solid and no-slipping particle immersed in a shear flow along a sufficiently porous slab is investigated. The fluid flow outside and inside of the slab is governed by the Stokes and Darcy equations, respectively, and the so-called Beavers and Joseph slip boundary conditions are enforced on the slab surface. The problem is solved for a distant particle with length scale a in terms of the small parameter a/ d where d designates the large particle-slab separation. This is achieved by asymptotically inverting a relevant boundary-integral equation on the particle surface, which has been recently proposed for any particle location (distant or close particle) in Khabthani et al. (J Fluid Mech 713:271-306, 2012). It is found that at order O( a/ d) the slab behaves for any particle shape as a solid plane no-slip wall while the slab properties (thickness, permeability, associated slip length) solely enter at O(( a/ d)2). Moreover, for a spherical particle, the numerical results published in Khabthani et al. (J Fluid Mech 713:271-306, 2012) perfectly agree with the present asymptotic analysis.

  17. Movement of spherical particles in capillaries using a boundary singularity method.

    PubMed

    Wang, W; Parker, K H

    1998-04-01

    As a first step to investigate the motion of blood cells in capillaries, we have studied the movement of a spherical particle falling in a vertical cylindrical tube using a boundary singularity method. The tube is filled with a Newtonian viscous fluid which would otherwise be stationary. The Reynolds number of the flow is much less than one. The sphere falls at arbitrary positions in the tube and is free to rotate. Point forces, Stokeslets, with unknown strength and direction, are distributed on the surfaces of the tube and the sphere. By forcing the flow field generated by all of the Stokeslets to satisfy proper boundary conditions, we solve for the strength and direction of each Stokeslet. The velocity, U, and rotation, omega, of the sphere are then calculated from a force and a torque balance. For a sphere falling on the axis of the tube, our results agree with Bohlin's approximate solution. When the sphere takes eccentric positions in the tube, it rotates as it translates down the tube, the direction of rotation being opposite to that it would have if the sphere rolled along the nearest side of the tube. This results from the zero net torque on the sphere and facilitates flow passing around the sphere. As the distance between the centre of the sphere and the axis of the tube increases, omega increases almost linearly, while U changes little. When the radius of the tube increases, U increases and approaches the Stokes velocity, while omega decreases rapidly. The boundary singularity method is relatively simple compared to other numerical methods and can be extended much more easily to the complex geometries typical of blood cells. PMID:9672088

  18. Time-of-flight analyzer system to detect reflected particles from a solid surface following low-energy particle injection

    SciTech Connect

    Yamaoka, H.; Tanaka, N.; Tsumori, K.; Nishiura, M.; Kenmotsu, T.; Hirouchi, T.; Kisaki, M.; Shinto, K.; Sasao, M.; Matsumoto, Y.; Wada, M.

    2008-02-15

    We have developed a time-of-flight analyzer to measure energy distributions of reflected particles from solid surfaces bombarded by low-energy (1-2 keV) ions. The analyzer yields energy distributions of neutrals which can be compared with the energy distributions of charged particles measured by a magnetic deflection-type momentum analyzer. We have tested the system to measure the angular dependence of energy and intensity for neutrals reflected from a polycrystalline W target. The energies of the reflected neutrals are much smaller than the incident ion energies, suggesting multiple scattering in the target. No angular dependence is observed under the condition that the sum of the incident and reflected angles is constant. The intensity of the reflected neutrals takes the maximum around the mirror angle. We compare these characteristics of neutral particle reflections with those of reflected ions.

  19. Suction-recirculation device for stabilizing particle flows within a solar powered solid particle receiver

    DOEpatents

    Kolb, Gregory J.

    2012-02-07

    A suction-recirculation device for stabilizing the flow of a curtain of blackened heat absorption particles falling inside of a solar receiver with an open aperture. The curtain of particles absorbs the concentrated heat from a solar mirror array reflected up to the receiver on a solar power tower. External winds entering the receiver at an oblique angle can destabilize the particle curtain and eject particles. A fan and ductwork is located behind the back wall of the receiver and sucks air out through an array of small holes in the back wall. Any entrained particles are separated out by a conventional cyclone device. Then, the air is recirculated back to the top of the receiver by injecting the recycled air through an array of small holes in the receiver's ceiling and upper aperture front wall. Since internal air is recirculated, heat losses are minimized and high receiver efficiency is maintained. Suction-recirculation velocities in the range of 1-5 m/s are sufficient to stabilize the particle curtain against external wind speeds in excess of 10 m/s.

  20. Modelling study of three-dimensional circulation and particle movement over the Sable Gully of Nova Scotia

    NASA Astrophysics Data System (ADS)

    Shan, Shiliang; Sheng, Jinyu; Greenan, Blair John William

    2014-01-01

    The Sable Gully is a broad deep underwater canyon located to the east of Sable Island on the edge of the Scotian Shelf. Being the home of many marine species including the endangered Northern Bottlenose Whale, the Gully was designated as a marine protected area (MPA) in 2004. Better understanding of physical environmental conditions over this MPA is needed for sustainable ecosystem management. In this study, a multi-nested ocean circulation model and a particle tracking model are used to examine the three-dimensional (3D) circulation and movement of particles carried passively by the flow over the Sable Gully. The 3D circulation model is driven by tides, wind, and surface heat/freshwater fluxes. The model performance is assessed by comparing the results with the previous numerical tidal results and current meter observations made in the Gully. The simulated tidal circulation over the Gully and adjacent waters is relatively strong on shallow banks and relatively weak on the continental slope. Below the depth of the Gully rim ( ˜ 200 m), the tidal currents are constrained by the thalweg of the Gully and amplified toward the Gully head. The simulated subtidal circulation in the Gully has a complex spatial structure and significant seasonal variability. The simulated time-dependent 3D flow fields are then used in a particle tracking model to study the particle movements, downstream and upstream areas, and residence time of the Gully. Based on the movements of particles released at the depth of the Gully rim and tracked forward in time, the e-folding residence time is estimated to be about 7 and 13 days in February and August 2006, respectively. The Gully flanks are identified as high retention areas with the typical residence time of 10 and 20 days in February and August 2006, respectively. Tracking particles with and without tides reveals that tidal circulation reduces the value of residence time in the Gully, particularly along the Gully flanks.

  1. Solid versus Liquid Particle Sampling Efficiency of Three Personal Aerosol Samplers when Facing the Wind

    PubMed Central

    Koehler, Kirsten A.; Anthony, T. Renee; Van Dyke, Michael

    2016-01-01

    The objective of this study was to examine the facing-the-wind sampling efficiency of three personal aerosol samplers as a function of particle phase (solid versus liquid). Samplers examined were the IOM, Button, and a prototype personal high-flow inhalable sampler head (PHISH). The prototype PHISH was designed to interface with the 37-mm closed-face cassette and provide an inhalable sample at 10 l min−1 of flow. Increased flow rate increases the amount of mass collected during a typical work shift and helps to ensure that limits of detection are met, particularly for well-controlled but highly toxic species. Two PHISH prototypes were tested: one with a screened inlet and one with a single-pore open-face inlet. Personal aerosol samplers were tested on a bluff-body disc that was rotated along the facing-the-wind axis to reduce spatiotemporal variability associated with sampling supermicron aerosol in low-velocity wind tunnels. When compared to published data for facing-wind aspiration efficiency for a mouth-breathing mannequin, the IOM oversampled relative to mannequin facing-the-wind aspiration efficiency for all sizes and particle types (solid and liquid). The sampling efficiency of the Button sampler was closer to the mannequin facing-the-wind aspiration efficiency than the IOM for solid particles, but the screened inlet removed most liquid particles, resulting in a large underestimation compared to the mannequin facing-the-wind aspiration efficiency. The open-face PHISH results showed overestimation for solid particles and underestimation for liquid particles when compared to the mannequin facing-the-wind aspiration efficiency. Substantial (and statistically significant) differences in sampling efficiency were observed between liquid and solid particles, particularly for the Button and screened-PHISH, with a majority of aerosol mass depositing on the screened inlets of these samplers. Our results suggest that large droplets have low penetration efficiencies

  2. Solid-Particle Erosion Behaviour of WC/Ni Composite Clad layers with Different Contents of WC Particles

    NASA Astrophysics Data System (ADS)

    Paul, C. P.; Mishra, S. K.; Tiwari, P.; Kukreja, L. M.

    2013-09-01

    We investigated the solid particle erosion behaviour of WC-reinforced Ni-matrix based laser clad layers to improve the performance of engineering components for potential power plant applications. WC-reinforced Ni-matrix based laser clad layers having various compositions of WC (5, 10 and 15wt%) were deposited on austenitic stainless steel substrates. The laser clad layers were characterised using optical and scanning electron microscopy, microhardness testing and air-jet erosion testing. In solid particle erosion studies using the air-jet erosion tester, the set of testing parameters, including air-erodent compositions, erodent particle velocities and impact angles, was selected by using the Taguchi technique. The morphologies of the worn surfaces were used to predict the wear mechanisms. The results of a microstructural examination of the cross-sections of laser clad revealed a good metallurgical bond between the WC-reinforced Ni matrix and the austenitic stainless steel substrate. Dissociation/partial melting/full melting of WC particles was not observed in the laser clad layers. The microhardness value in the laser cladding zone was between 900-2400 VHN, while it was 230-270 VHN on the substrate. The results of erosion wear studies of the WC-Ni laser clad surface revealed that the erosion behaviour of the WC-Ni laser clad is primarily governed by erodent jet velocity followed by impact angle. The erosion does not much depend on the Ni-concentration in the MMC or the erodent feed rate. The wear signature at the erosion wear surface indicated that the erosion was primarily governed by a ductile erosion mechanism followed by the removal of WC particles from the matrix. The erosion resistance of the Ni-clad layer with WC was found to be at least four times higher than that without WC particles. The quantified contribution of various erosion parameters is useful for function-based design of components with extended service life.

  3. Reentrant Solid-Liquid Transition in Ionic Colloidal Dispersions by Varying Particle Charge Density

    NASA Astrophysics Data System (ADS)

    Yamanaka, Junpei; Yoshida, Hiroshi; Koga, Tadanori; Ise, Norio; Hashimoto, Takeji

    1998-06-01

    The influence of the particle surface charge density on the solid-liquid phase transition in electrostatically stabilized colloidal silica and polymer latex dispersions is examined. Both systems show a reentrant transition with increasing charge density. This is not explainable in terms of the Yukawa potential and the charge-renormalization model.

  4. Effects of ground corn particle size on ethanol yield and thin stillage soluble solids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of ground corn particle size on ethanol yield and soluble solids in thin stillage were evaluated using a 2-L laboratory dry-grind procedure. The procedure was optimized for grinding, liquefaction, saccharification, and fermentation parameters. The optimized procedure was reproducible wi...

  5. A new method of imaging particle tracks in solid state nuclear track detectors.

    PubMed

    Wertheim, D; Gillmore, G; Brown, L; Petford, N

    2010-01-01

    Solid state nuclear track detectors are used to determine the concentration of alpha particles in the environment. The standard method for assessing exposed detectors involves 2D image analysis. However 3D imaging has the potential to provide additional information relating to angle as well as to differentiate clustered hit sequences and possibly energy of alpha particles but this could be time consuming. Here we describe a new method for rapid high-resolution 3D imaging of solid state nuclear track detectors. A 'LEXT' OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) was used in confocal mode to successfully obtain 3D image data on four CR-39 plastic detectors. Three-dimensional visualization and image analysis enabled characterization of track features. This method may provide a means of rapid and detailed 3D analysis of solid state nuclear track detectors.

  6. Parallel algorithm for transient solid dynamics simulations using finite elements and smoothed particle hydrodynamics

    SciTech Connect

    Attaway, S.W.; Hendrickson, B.A.; Plimpton, S.J.; Swegle, J.W.; Gardner, D.R.; Vaughan, C.T.

    1997-05-01

    An efficient, scalable, parallel algorithm for treating contacts in solid mechanics has been applied to interactions between particles in smooth particle hydrodynamics (SPH). The algorithm uses three different decompositions within a single timestep: (1) a static FE-decomposition of mesh elements; (2) a dynamic SPH-decomposition of SPH particles; (3) and a dynamic contact-decomposition of contact nodes and SPH particles. The overhead cost of such a scheme is the cost of moving mesh and particle data between the decompositions. This cost turns out to be small in practice, leading to a highly load-balanced decomposition in which to perform each of the three major computational states within a timestep.

  7. Flow Mapping in a Gas-Solid Riser via Computer Automated Radioactive Particle Tracking (CARPT)

    SciTech Connect

    Muthanna Al-Dahhan; Milorad P. Dudukovic; Satish Bhusarapu; Timothy J. O'hern; Steven Trujillo; Michael R. Prairie

    2005-06-04

    Statement of the Problem: Developing and disseminating a general and experimentally validated model for turbulent multiphase fluid dynamics suitable for engineering design purposes in industrial scale applications of riser reactors and pneumatic conveying, require collecting reliable data on solids trajectories, velocities ? averaged and instantaneous, solids holdup distribution and solids fluxes in the riser as a function of operating conditions. Such data are currently not available on the same system. Multiphase Fluid Dynamics Research Consortium (MFDRC) was established to address these issues on a chosen example of circulating fluidized bed (CFB) reactor, which is widely used in petroleum and chemical industry including coal combustion. This project addresses the problem of lacking reliable data to advance CFB technology. Project Objectives: The objective of this project is to advance the understanding of the solids flow pattern and mixing in a well-developed flow region of a gas-solid riser, operated at different gas flow rates and solids loading using the state-of-the-art non-intrusive measurements. This work creates an insight and reliable database for local solids fluid-dynamic quantities in a pilot-plant scale CFB, which can then be used to validate/develop phenomenological models for the riser. This study also attempts to provide benchmark data for validation of Computational Fluid Dynamic (CFD) codes and their current closures. Technical Approach: Non-Invasive Computer Automated Radioactive Particle Tracking (CARPT) technique provides complete Eulerian solids flow field (time average velocity map and various turbulence parameters such as the Reynolds stresses, turbulent kinetic energy, and eddy diffusivities). It also gives directly the Lagrangian information of solids flow and yields the true solids residence time distribution (RTD). Another radiation based technique, Computed Tomography (CT) yields detailed time averaged local holdup profiles at

  8. Enhancing 18F uptake in a single particle for positron emission particle tracking through modification of solid surface chemistry

    NASA Astrophysics Data System (ADS)

    Fan, X.; Parker, D. J.; Smith, M. D.

    2006-03-01

    The positron emission particle tracking (PEPT) technique has been widely used in science and engineering to obtain detailed information on particulate motion in granular materials and flow fields in multiphase systems. The technique involves tracking a single radioactively labelled particle by detecting the pairs of back-to-back 511 keV γ-rays arising from annihilation of emitted positrons. It is thus crucially dependent on the availability of suitably labelled tracer particles. With the present equipment, the optimum activity for a PEPT tracer is between 300 and 1000 μCi. The positron emitting radionuclide most often used is 18F in the form of fluoride ions. However, most materials have a very poor capacity to take up fluoride naturally. This paper presents a surface modification technique which was developed to improve the adsorption of 18F on solids and therefore extending the application of PEPT. For example, 200 μm MCC particles are the subject of many PEPT studies, but these particles only adsorb a few μCi 18F naturally, and cannot be used as tracers for PEPT. After surface modification, they take up about 700 μCi 18F, and can be tracked very well using PEPT.

  9. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    PubMed

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-21

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization. PMID:26948023

  10. Single-particle characterization of municipal solid waste (MSW) ash particles using low- Z particle electron probe X-ray microanalysis

    NASA Astrophysics Data System (ADS)

    Hwang, HeeJin; Ro, Chul-Un

    Environmentally benign treatment of municipal solid waste (MSW) ashes has been a worldwide issue since more countries are implementing incineration to reduce waste volume. A single-particle analytical technique, named low- Z particle electron probe X-ray microanalysis (low- Z particle EPMA) was applied to characterize MSW fly- and bottom-ash particle samples collected from two municipal incinerators in Korea. According to their chemical composition, many distinctive particle types were identified. For fly ash sample collected in one incinerator (sample S1), where lime slurry injection is used for acid-gas treatment, CaCO 3-containing particles (28.4%) are the most abundantly encountered, followed by carbonaceous (23.6%), SiO 2-containing (13.8%), NaCl-containing (13.1%), and iron-containing (10.5%) particles. For fly ash sample collected at the other incinerator (sample S2), NaCl-containing particles (40.4%) are the most abundantly encountered, followed by iron-containing (29.1%), carbonaceous (11.8%), CaCO 3-containing (2.2%), and SiO 2-containing (7.0%) particles. For bottom ash sample collected at one incinerator (sample S3), iron-containing particles (46.6%) are the most abundantly encountered, followed by CaCO 3-containing (17.3%), carbonaceous (16.6%), and Si and/or Al oxide-containing (15.8%) particles. For bottom ash sample collected in the other incinerator (sample S4), iron-containing particles (63.4%) are also the most abundantly encountered, followed by carbonaceous (14.0%), CaCO 3-containing (10.0%), and Si and/or Al oxide-containing (6.1%) particles. Chemical compositions of the two bottom ash samples are not much different compared to those of the two fly ash samples. It was demonstrated that the single-particle characterization using this low- Z particle EPMA technique provided detailed information on various types of chemical species in the MSW ash samples. In addition, the technique has advantage over conventional analytical techniques in the

  11. Investigation of Gas Solid Fluidized Bed Dynamics with Non-Spherical Particles

    SciTech Connect

    Choudhuri, Ahsan

    2013-06-30

    One of the largest challenges for 21st century is to fulfill global energy demand while also reducing detrimental impacts of energy generation and use on the environment. Gasification is a promising technology to meet the requirement of reduced emissions without compromising performance. Coal gasification is not an incinerating process; rather than burning coal completely a partial combustion takes place in the presence of steam and limited amounts of oxygen. In this controlled environment, a chemical reaction takes place to produce a mixture of clean synthetic gas. Gas-solid fluidized bed is one such type of gasification technology. During gasification, the mixing behavior of solid (coal) and gas and their flow patterns can be very complicated to understand. Many attempts have taken place in laboratory scale to understand bed hydrodynamics with spherical particles though in actual applications with coal, the particles are non-spherical. This issue drove the documented attempt presented here to investigate fluidized bed behavior using different ranges of non-spherical particles, as well as spherical. For this investigation, various parameters are controlled that included particle size, bed height, bed diameter and particle shape. Particles ranged from 355 µm to 1180 µm, bed diameter varied from 2 cm to 7 cm, two fluidized beds with diameters of 3.4 cm and 12.4 cm, for the spherical and non-spherical shaped particles that were taken into consideration. Pressure drop was measured with increasing superficial gas velocity. The velocity required in order to start to fluidize the particle is called the minimum fluidization velocity, which is one of the most important parameters to design and optimize within a gas-solid fluidized bed. This minimum fluidization velocity was monitored during investigation while observing variables factors and their effect on this velocity. From our investigation, it has been found that minimum fluidization velocity is independent of bed

  12. Automated oligonucleotide solid-phase synthesis on nanosized silica particles using nano-on-micro assembled particle supports.

    PubMed

    Farre, Carole; Lansalot, Muriel; Bazzi, Rana; Roux, Stéphane; Marquette, Christophe A; Catanante, Gaëlle; Blum, Loïc J; Charvet, Nicolas; Louis, Cédric; Chaix, Carole

    2010-04-01

    This article describes an original strategy to enable solid-phase oligodeoxyribonucleotide (ODN) synthesis on nanosized silica particles. It consists of the reversible immobilization of silica nanoparticles (NPs) on micrometric silica beads. The resulting assemblies, called nano-on-micro (NOM) systems, are well adapted to ODN synthesis in an automated instrument. First, NPs are derivatized with OH functions. For NOM assembly preparation, these functions react with the silanols of the microbeads under specific experimental conditions. Furthermore, OH groups allow ODN synthesis on the nanoparticles via phosphoramidite chemistry. The stability of the NOM assemblies during ODN solid-phase synthesis is confirmed by scanning and transmission electron microscopy (SEM and TEM, respectively), together with dynamic light scattering analyses. Then, the release of ODN-functionalized nanoparticles is performed under mild conditions (1% NH(4)OH in water, 1 h, 60 degrees C). Our technique provides silica nanoparticles well functionalized with oligonucleotides, as demonstrated by hybridization experiments conducted with the cDNA target.

  13. Spontaneous concentrations of solids through two-way drag forces between gas and sedimenting particles

    NASA Astrophysics Data System (ADS)

    Lambrechts, M.; Johansen, A.; Capelo, H. L.; Blum, J.; Bodenschatz, E.

    2016-06-01

    The behaviour of sedimenting particles depends on the dust-to-gas ratio of the fluid. Linear stability analysis shows that solids settling in the Epstein drag regime would remain homogeneously distributed in non-rotating incompressible fluids, even when dust-to-gas ratios reach unity. However, the nonlinear evolution has not been probed before. Here, we present numerical calculations indicating that, in a particle-dense mixture, solids spontaneously mix out of the fluid and form swarms that are overdense in particles by at least a factor 10. The instability is caused by mass-loaded regions locally breaking the equilibrium background stratification. The driving mechanism depends on nonlinear perturbations of the background flow and shares some similarity to the streaming instability in accretion discs. The resulting particle-rich swarms may stimulate particle growth by coagulation. In the context of protoplanetary discs, the instability could be relevant for aiding small particles to settle to the midplane in the outer disc. Inside the gas envelopes of protoplanets, enhanced settling may lead to a reduced dust opacity, which facilitates the contraction of the envelope. We show that the relevant physical set up can be recreated in a laboratory setting. This will allow our numerical calculations to be investigated experimentally in the future.

  14. Impact of in situ polymer coating on particle dispersion into solid laser-generated nanocomposites.

    PubMed

    Wagener, Philipp; Brandes, Gudrun; Schwenke, Andreas; Barcikowski, Stephan

    2011-03-21

    The crucial step in the production of solid nanocomposites is the uniform embedding of nanoparticles into the polymer matrix, since the colloidal properties or specific physical properties are very sensitive to particle dispersion within the nanocomposite. Therefore, we studied a laser-based generation method of a nanocomposite which enables us to control the agglomeration of nanoparticles and to increase the single particle dispersion within polyurethane. For this purpose, we ablated targets of silver and copper inside a polymer-doped solution of tetrahydrofuran by a picosecond laser (using a pulse energy of 125 μJ at 33.3 kHz repetition rate) and hardened the resulting colloids into solid polymers. Electron microscopy of these nanocomposites revealed that primary particle size, agglomerate size and particle dispersion strongly depend on concentration of the polyurethane added before laser ablation. 0.3 wt% polyurethane is the optimal polymer concentration to produce nanocomposites with improved particle dispersion and adequate productivity. Lower polyurethane concentration results in agglomeration whereas higher concentration reduces the production rate significantly. The following evaporation step did not change the distribution of the nanocomposite inside the polyurethane matrix. Hence, the in situ coating of nanoparticles with polyurethane during laser ablation enables simple integration into the structural analogue polymer matrix without additives. Furthermore, it was possible to injection mold these in situ-stabilized nanocomposites without affecting particle dispersion. This clarifies that sufficient in situ stabilization during laser ablation in polymer solution is able to prevent agglomeration even in a hot polymer melt. PMID:21298127

  15. On the high fidelity simulation of chemical explosions and their interaction with solid particle clouds

    NASA Astrophysics Data System (ADS)

    Balakrishnan, Kaushik

    The flow field behind chemical explosions in multiphase environments is investigated using a robust, state-of-the-art simulation strategy that accounts for the thermodynamics, gas dynamics and fluid mechanics of relevance to the problem. Focus is laid on the investigation of blast wave propagation, growth of hydrodynamic instabilities behind explosive blasts, the mixing aspects behind explosions, the effects of afterburn and its quantification, and the role played by solid particles in these phenomena. In particular, the confluence and interplay of these different physical phenomena are explored from a fundamental perspective, and applied to the problem of chemical explosions. A solid phase solver suited for the study of high-speed, two-phase flows has been developed and validated. This solver accounts for the inter-phase mass, momentum and energy transfer through empirical laws, and ensures two-way coupling between the two phases, viz. solid particles and gas. For dense flow fields, i.e., when the solid volume fraction becomes non-negligible (˜60%), the finite volume method with a Godunov type shock-capturing scheme requires modifications to account for volume fraction gradients during the computation of cell interface gas fluxes. To this end, the simulation methodology is extended with the formulation of an Eulerian gas, Lagrangian solid approach, thereby ensuring that the so developed two-phase simulation strategy can be applied for both flow conditions, dilute and dense alike. Moreover, under dense loading conditions the solid particles inevitably collide, which is accounted for in the current research effort with the use of an empirical collision/contact model from literature. Furthermore, the post-detonation flow field consists of gases under extreme temperature and pressure conditions, necessitating the use of real gas equations of state in the multiphase model. This overall simulation strategy is then extended to the investigation of chemical explosions in

  16. Biodegradation of organic compounds sequestered in organic solids or in nanopores within silica particles

    SciTech Connect

    Hatzinger, P.B.; Alexander, M.

    1997-11-01

    A study was conducted using model solids to determine whether the time-dependent decline in availability for biodegradation of organic pollutants in soil might result from the entrapment of these compounds in porous or nonporous solids. A strain of Pseudomonas mineralized phenanthrene in solid alkanes containing 18 to 32 carbons, three waxes, and low-molecular-weight polycaprolactone, polyethylene, and polypropylene. The rates were appreciably slower than when the substrate was not initially present within these nonporous solids. From 1.4 to 63.4% of the polycyclic aromatic hydrocarbon added to the solids was mineralized in 90 d. The rates and extents of partitioning of phenanthrene varied markedly among the solids. The rates of partitioning and biodegradation of phenanthrene initially present in the alkanes were positively correlated. The bacterium rapidly and extensively mineralized phenanthrene provided in calcium alginate beads containing varying amounts of soluble soil organic matter. The rates and extents of phenanthrene mineralization declined as the percentage of the substrate in the nanopores within silica particles increased, but the reductions in rate, extent, or both were less pronounced than with nonporous solids. The rate of 4-nitrophenol biodegradation also declined with increasing percentages of the compound in these nanopores. The data are consistent with hypotheses that the sequestration and consequent decrease in bioavailability of organic compounds that persist in soil result from their partitioning into organic matter or their presence within nanopores in soil.

  17. Integration of active pharmaceutical ingredient solid form selection and particle engineering into drug product design.

    PubMed

    Ticehurst, Martyn David; Marziano, Ivan

    2015-06-01

    This review seeks to offer a broad perspective that encompasses an understanding of the drug product attributes affected by active pharmaceutical ingredient (API) physical properties, their link to solid form selection and the role of particle engineering. While the crucial role of active pharmaceutical ingredient (API) solid form selection is universally acknowledged in the pharmaceutical industry, the value of increasing effort to understanding the link between solid form, API physical properties and drug product formulation and manufacture is now also being recognised. A truly holistic strategy for drug product development should focus on connecting solid form selection, particle engineering and formulation design to both exploit opportunities to access simpler manufacturing operations and prevent failures. Modelling and predictive tools that assist in establishing these links early in product development are discussed. In addition, the potential for differences between the ingoing API physical properties and those in the final product caused by drug product processing is considered. The focus of this review is on oral solid dosage forms and dry powder inhaler products for lung delivery.

  18. The Effect of Solid Constituent Particle Size Distributions on TP-H1148 Propellant Slag

    NASA Technical Reports Server (NTRS)

    May, Douglas H.; Miles, William L.; Taylor, David S.; Rackham, Jon L.

    1997-01-01

    Special aluminum and ammonium perchlorate (AP) particle size distributions were prepared for a matrix of five-inch diameter, center-perforated (CP) motor tests to measure the aluminum oxide slag response in Space Shuttle Reusable Solid Rocket Motor (RSRM) propellant. Previous tests of TP-H1148 propellant in five-inch CP spin motors have shown a correlation between aluminum particle size and generated slag. The motors for this study were cast from thirteen five-gallon propellant mixes which used five particle size levels of aluminum powder, five of unground AP and three of ground AP. Aluminum had the greatest effect on slag formation, the more coarse fractions causing greater slag quantities and larger slag particles. Unground AP had about half the effect of aluminum with the coarser fractions again producing more and larger sized slag particles. The variation in ground AP did not have a significant effect on slag formation. Quench bomb tests showed the same trends as the spin motors, that is, larger aluminum and AP particle size distributions generated larger slag particles leaving the propellant surface. Cured propellant mechanical properties were also impacted by particle size variation.

  19. Direct Numerical Simulation of Particle Behaviour in a Gas-Solid Three Dimensional Plane Jet

    SciTech Connect

    Qazi, N. A.; Tang, J. C. K.; Hawkes, E. R.; Yeoh, G. H.; Grout, Ray W.; Sitaraman, Hariswaran; Talei, M.; Taylor, R. A.; Bolla, M.; Wang, H.

    2014-12-08

    In this paper, direct numerical simulations (DNS) of a three-dimensional (3D), non-reacting, temporally evolving planar jet laden with mono-dispersed solid particles in the two-way coupling (TWC) regime are performed. Three different particles Stokes numbers (St = 0.1, 1, 10) have been considered. This has been achieved by varying the particle diameter while keeping the particle mass loading (fm = 1) and the jet Reynolds number (Rejet = 2000) unchanged. The objective is to study the effect of the particle Stokes number TWC regime on the temporal development of the planar jet. Two-way coupled momentum and heat transfer has been studied by investigating mean relative velocity and temperature. Results indicate that the relative parameters are more pronounced on the edges of the jet and decrease in time in general. At the center of the jet however, the mean value first increases and then decreases again. Additionally, lighter particles spread farther than heavier particles from the center of the jet. Furthermore, the heavier particles delay the development of the jet due to TWC effects.

  20. The effects of solid rocket motor effluents on selected surfaces and solid particle size, distribution, and composition for simulated shuttle booster separation motors

    NASA Technical Reports Server (NTRS)

    Jex, D. W.; Linton, R. C.; Russell, W. M.; Trenkle, J. J.; Wilkes, D. R.

    1976-01-01

    A series of three tests was conducted using solid rocket propellants to determine the effects a solid rocket plume would have on thermal protective surfaces (TPS). The surfaces tested were those which are baselined for the shuttle vehicle. The propellants used were to simulate the separation solid rocket motors (SSRM) that separate the solid rocket boosters (SRB) from the shuttle launch vehicle. Data cover: (1) the optical effects of the plume environment on spacecraft related surfaces, and (2) the solid particle size, distribution, and composition at TPS sample locations.

  1. Jumping liquid metal droplet in electrolyte triggered by solid metal particles

    NASA Astrophysics Data System (ADS)

    Tang, Jianbo; Wang, Junjie; Liu, Jing; Zhou, Yuan

    2016-05-01

    We report the electron discharge effect due to point contact between liquid metal and solid metal particles in electrolyte. Adding nickel particles induces drastic hydrogen generating and intermittent jumping of a sub-millimeter EGaIn droplet in NaOH solution. Observations from different orientations disclose that such jumping behavior is triggered by pressurized bubbles under the assistance of interfacial interactions. Hydrogen evolution around particles provides clear evidence that such electric instability originates from the varied electric potential and morphology between the two metallic materials. The point-contact-induced charge concentration significantly enhances the near-surface electric field intensity at the particle tips and thus causes electric breakdown of the electrolyte.

  2. Size distribution of unburned aluminum particles in solid propellant rocket motor exhaust

    SciTech Connect

    Larson, R.S.

    1986-06-01

    The size distribution of particles of unburned aluminum exiting a solid propellant rocket chamber is calculated by extending a previously developed theoretical model. Both one-dimensional and two-dimensional approximations to the chamber flow field are considered, but particle velocity lags are neglected. Results of the one-dimensional analysis differ from the more realistic two-dimensional results in that they predict a lower overall combustion efficiency and a most probable particle size which is always greater than zero. It is argued that these observations can be explained by the fact that the one-dimensional flow field allows many particles to pass through the chamber with a very short residence time.

  3. Dependence of charge transfer phenomena during solid-air two-phase flow on particle disperser

    NASA Astrophysics Data System (ADS)

    Tanoue, Ken-ichiro; Suedomi, Yuuki; Honda, Hirotaka; Furutani, Satoshi; Nishimura, Tatsuo; Masuda, Hiroaki

    2012-12-01

    An experimental investigation of the tribo-electrification of particles has been conducted during solid-air two-phase turbulent flow. The current induced in a metal plate by the impact of polymethylmethacrylate (PMMA) particles in a high-speed air flow was measured for two different plate materials. The results indicated that the contact potential difference between the particles and a stainless steel plate was positive, while for a nickel plate it was negative. These results agreed with theoretical contact charge transfer even if not only the particle size but also the kind of metal plate was changed. The specific charge of the PMMA particles during solid-air two-phase flow using an ejector, a stainless steel branch pipe, and a stainless steel straight pipe was measured using a Faraday cage. Although the charge was negative in the ejector, the particles had a positive specific charge at the outlet of the branch pipe, and this positive charge increased in the straight pipe. The charge decay along the flow direction could be reproduced by the charging and relaxation theory. However, the proportional coefficients in the theory changed with the particle size and air velocity. Therefore, an unexpected charge transfer occurred between the ejector and the branch pipe, which could not be explained solely by the contact potential difference. In the ejector, an electrical current in air might have been produced by self-discharge of particles with excess charge between the nickel diffuser in the ejector and the stainless steel nozzle or the stainless steel pipe due to a reversal in the contact potential difference between the PMMA and the stainless steel. The sign of the current depended on the particle size, possibly because the position where the particles impacted depended on their size. When dual coaxial glass pipes were used as a particle disperser, the specific charge of the PMMA particles became more positive along the particle flow direction due to the contact

  4. Porous Silica-Supported Solid Lipid Particles for Enhanced Solubilization of Poorly Soluble Drugs.

    PubMed

    Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen E; Prestidge, Clive A

    2016-07-01

    Low dissolution of drugs in the intestinal fluid can limit their effectiveness in oral therapies. Here, a novel porous silica-supported solid lipid system was developed to optimize the oral delivery of drugs with limited aqueous solubility. Using lovastatin (LOV) as the model poorly water-soluble drug, two porous silica-supported solid lipid systems (SSL-A and SSL-S) were fabricated from solid lipid (glyceryl monostearate, GMS) and nanoporous silica particles Aerosil 380 (silica-A) and Syloid 244FP (silica-S) via immersion/solvent evaporation. SSL particles demonstrated significantly higher rate and extent of lipolysis in comparison with the pure solid lipid, depending on the lipid loading levels and the morphology. The highest lipid digestion was observed when silica-S was loaded with 34% (w/w) solid lipid, and differential scanning calorimeter (DSC) analysis confirmed the encapsulation of up to 2% (w/w) non-crystalline LOV in this optimal SSL-S formulation. Drug dissolution under non-digesting intestinal conditions revealed a three- to sixfold increase in dissolution efficiencies when compared to the unformulated drug and a LOV-lipid suspension. Furthermore, the SSL-S provided superior drug solubilization under simulated intestinal digesting condition in comparison with the drug-lipid suspension and drug-loaded silica. Therefore, solid lipid and nanoporous silica provides a synergistic effect on optimizing the solubilization of poorly water-soluble compound and the solid lipid-based porous carrier system provides a promising delivery approach to overcome the oral delivery challenges of poorly water-soluble drugs.

  5. Porous Silica-Supported Solid Lipid Particles for Enhanced Solubilization of Poorly Soluble Drugs.

    PubMed

    Yasmin, Rokhsana; Rao, Shasha; Bremmell, Kristen E; Prestidge, Clive A

    2016-07-01

    Low dissolution of drugs in the intestinal fluid can limit their effectiveness in oral therapies. Here, a novel porous silica-supported solid lipid system was developed to optimize the oral delivery of drugs with limited aqueous solubility. Using lovastatin (LOV) as the model poorly water-soluble drug, two porous silica-supported solid lipid systems (SSL-A and SSL-S) were fabricated from solid lipid (glyceryl monostearate, GMS) and nanoporous silica particles Aerosil 380 (silica-A) and Syloid 244FP (silica-S) via immersion/solvent evaporation. SSL particles demonstrated significantly higher rate and extent of lipolysis in comparison with the pure solid lipid, depending on the lipid loading levels and the morphology. The highest lipid digestion was observed when silica-S was loaded with 34% (w/w) solid lipid, and differential scanning calorimeter (DSC) analysis confirmed the encapsulation of up to 2% (w/w) non-crystalline LOV in this optimal SSL-S formulation. Drug dissolution under non-digesting intestinal conditions revealed a three- to sixfold increase in dissolution efficiencies when compared to the unformulated drug and a LOV-lipid suspension. Furthermore, the SSL-S provided superior drug solubilization under simulated intestinal digesting condition in comparison with the drug-lipid suspension and drug-loaded silica. Therefore, solid lipid and nanoporous silica provides a synergistic effect on optimizing the solubilization of poorly water-soluble compound and the solid lipid-based porous carrier system provides a promising delivery approach to overcome the oral delivery challenges of poorly water-soluble drugs. PMID:27048207

  6. Ratios of total suspended solids to suspended sediment concentrations by particle size

    USGS Publications Warehouse

    Selbig, W.R.; Bannerman, R.T.

    2011-01-01

    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  7. Kinetics of gas-to-liquid and liquid-to-solid transfer of particles in metal-matrix composites

    NASA Technical Reports Server (NTRS)

    Stefanescu, D. M.; Rana, F.; Moitra, A.; Kacar, S.

    1990-01-01

    Analytical models for transfer of particles from gas to liquid and from liquid to solid are introduced. The model for calculation of the pushing/engulfment transition in directionally solidified particulate metal matrix composites, considers process thermodynamics, process kinetics, thermophysical properties and buoyant forces. Based on processing variables (solidification velocity and direction) and on material variables (interface energies, particle size, particle and liquid density, volume fraction of particles and particle/liquid thermal conductivity ratio) four types of behavior were predicted. Also, two numerical models for liquid-to-solid transfer are discussed, as well as the limitations of presently available models.

  8. A smooth dissipative particle dynamics method for domains with arbitrary-geometry solid boundaries

    NASA Astrophysics Data System (ADS)

    Gatsonis, Nikolaos A.; Potami, Raffaele; Yang, Jun

    2014-01-01

    A smooth dissipative particle dynamics method with dynamic virtual particle allocation (SDPD-DV) for modeling and simulation of mesoscopic fluids in wall-bounded domains is presented. The physical domain in SDPD-DV may contain external and internal solid boundaries of arbitrary geometries, periodic inlets and outlets, and the fluid region. The SDPD-DV method is realized with fluid particles, boundary particles, and dynamically allocated virtual particles. The internal or external solid boundaries of the domain can be of arbitrary geometry and are discretized with a surface grid. These boundaries are represented by boundary particles with assigned properties. The fluid domain is discretized with fluid particles of constant mass and variable volume. Conservative and dissipative force models due to virtual particles exerted on a fluid particle in the proximity of a solid boundary supplement the original SDPD formulation. The dynamic virtual particle allocation approach provides the density and the forces due to virtual particles. The integration of the SDPD equations is accomplished with a velocity-Verlet algorithm for the momentum and a Runge-Kutta for the entropy equation. The velocity integrator is supplemented by a bounce-forward algorithm in cases where the virtual particle force model is not able to prevent particle penetration. For the incompressible isothermal systems considered in this work, the pressure of a fluid particle is obtained by an artificial compressibility formulation for liquids and the ideal gas law for gases. The self-diffusion coefficient is obtained by an implementation of the generalized Einstein and the Green-Kubo relations. Field properties are obtained by sampling SDPD-DV outputs on a post-processing grid that allows harnessing the particle information on desired spatiotemporal scales. The SDPD-DV method is verified and validated with simulations in bounded and periodic domains that cover the hydrodynamic and mesoscopic regimes for

  9. From porous gold nanocups to porous nanospheres and solid particles--a new synthetic approach.

    PubMed

    Ihsan, Ayesha; Katsiev, Habib; Alyami, Noktan; Anjum, Dalaver H; Khan, Waheed S; Hussain, Irshad

    2015-05-15

    We report a versatile approach for the synthesis of porous gold nanocups, porous gold nanospheres and solid gold nanoparticles. Gold nanocups are formed by the slow reduction of gold salt (HAuCl4⋅3H2O) using aminoantipyrene (AAP) as a reducing agent. Adding polyvinylpyrrolidone (PVP) to the gold salt followed by reduction with AAP resulted in the formation of porous gold nanospheres. Microwave irradiation of both of these porous gold particles resulted in the formation of slightly smaller but solid gold particles. All these nanoparticles are thoroughly characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and bright-field tomography. Due to the larger size, porous nature, low density and higher surface area, these nanomaterials may have interesting applications in catalysis, drug delivery, phototherapy and sensing.

  10. The dissolution kinetics of major elements in municipal solid waste incineration bottom ash particles

    NASA Astrophysics Data System (ADS)

    Bendz, David; Tüchsen, Peter L.; Christensen, Thomas H.

    2007-12-01

    Leaching and tracer experiments in batches at L/S 20 were performed with 3-month-old MSWI bottom ash separated into eight different particle sizes. The time-dependent leaching of major elements (Ca 2+, K +, Na +, Cl - and SO 4- 2 ) was monitored for up to 747 h. Physical properties of the particles, the specific surface (BET), pore volume and pore volume distribution over pore sizes (BJH) were determined for all particle classes by N 2 adsorption/desorption experiments. Some common features of physical pore structure for all particles were revealed. The specific surface and the particle pore volume were found to be negatively correlated with particle size, ranging from 3.2 m 2/g to 25.7 m 2/g for the surface area and from 0.0086 cm 3/g to 0.091 cm 3/g for the pore volume. Not surprisingly, the specific surface area was found to be the major material parameter that governed the leaching behavior for all elements (Ca 2+, K +, Na +, Cl - and SO 4- 2 ) and particle sizes. The diffusion resistance was determined independently by separate tracer (tritium) experiments. Diffusion gave a significant contribution to the apparent leaching kinetics for all elements during the first 10-40 h (depending on the particle size) of leaching and surface reaction was the overall rate controlling mechanism at late times for all particle sizes. For Ca 2+ and SO 4- 2 , the coupled effect of diffusion resistance and the degree of undersaturation in the intra particle pore volume was found to be a major rate limiting dissolution mechanism for both early and late times. The solubility control in the intra particulate porosity may undermine any attempt to treat bottom ash by washing out the sulfate. Even for high liquid/solid ratios, the solubility in the intra-particular porosity will limit the release rate.

  11. Development of stress boundary conditions in smoothed particle hydrodynamics (SPH) for the modeling of solids deformation

    NASA Astrophysics Data System (ADS)

    Douillet-Grellier, Thomas; Pramanik, Ranjan; Pan, Kai; Albaiz, Abdulaziz; Jones, Bruce D.; Williams, John R.

    2016-10-01

    This paper develops a method for imposing stress boundary conditions in smoothed particle hydrodynamics (SPH) with and without the need for dummy particles. SPH has been used for simulating phenomena in a number of fields, such as astrophysics and fluid mechanics. More recently, the method has gained traction as a technique for simulation of deformation and fracture in solids, where the meshless property of SPH can be leveraged to represent arbitrary crack paths. Despite this interest, application of boundary conditions within the SPH framework is typically limited to imposed velocity or displacement using fictitious dummy particles to compensate for the lack of particles beyond the boundary interface. While this is enough for a large variety of problems, especially in the case of fluid flow, for problems in solid mechanics there is a clear need to impose stresses upon boundaries. In addition to this, the use of dummy particles to impose a boundary condition is not always suitable or even feasibly, especially for those problems which include internal boundaries. In order to overcome these difficulties, this paper first presents an improved method for applying stress boundary conditions in SPH with dummy particles. This is then followed by a proposal of a formulation which does not require dummy particles. These techniques are then validated against analytical solutions to two common problems in rock mechanics, the Brazilian test and the penny-shaped crack problem both in 2D and 3D. This study highlights the fact that SPH offers a good level of accuracy to solve these problems and that results are reliable. This validation work serves as a foundation for addressing more complex problems involving plasticity and fracture propagation.

  12. Can Infrared Spectroscopy Be Used to Measure Change in Potassium Nitrate Concentration as a Proxy for Soil Particle Movement?

    PubMed Central

    Luleva, Mila Ivanova; van der Werff, Harald; Jetten, Victor; van der Meer, Freek

    2011-01-01

    Displacement of soil particles caused by erosion influences soil condition and fertility. To date, the cesium 137 isotope (137Cs) technique is most commonly used for soil particle tracing. However when large areas are considered, the expensive soil sampling and analysis present an obstacle. Infrared spectral measurements would provide a solution, however the small concentrations of the isotope do not influence the spectral signal sufficiently. Potassium (K) has similar electrical, chemical and physical properties as Cs. Our hypothesis is that it can be used as possible replacement in soil particle tracing. Soils differing in texture were sampled for the study. Laboratory soil chemical analyses and spectral sensitivity analyses were carried out to identify the wavelength range related to K concentration. Different concentrations of K fertilizer were added to soils with varying texture properties in order to establish spectral characteristics of the absorption feature associated with the element. Changes in position of absorption feature center were observed at wavelengths between 2,450 and 2,470 nm, depending on the amount of fertilizer applied. Other absorption feature parameters (absorption band depth, width and area) were also found to change with K concentration with coefficient of determination between 0.85 and 0.99. Tracing soil particles using K fertilizer and infrared spectral response is considered suitable for soils with sandy and sandy silt texture. It is a new approach that can potentially grow to a technique for rapid monitoring of soil particle movement over large areas. PMID:22163843

  13. Solid Particle Erosion Behaviors of Carbon-Fiber Epoxy Composite and Pure Titanium

    NASA Astrophysics Data System (ADS)

    Cai, Feng; Gao, Feng; Pant, Shashank; Huang, Xiao; Yang, Qi

    2016-01-01

    Rotor blades of Bell CH-146 Griffon helicopter experience excessive solid particle erosion at low altitudes in desert environment. The rotor blade is made of an advanced light-weight composite which, however, has a low resistance to solid particle erosion. Coatings have been developed and applied to protect the composite blade. However, due to the influence of coating process on composite material, the compatibility between coating and composite base, and the challenges of repairing damaged coatings as well as the inconsistency between the old and new coatings, replaceable thin metal shielding is an alternative approach; and titanium, due to its high-specific strength and better formability, is an ideal candidate. This work investigates solid particle erosion behaviors of carbon-fiber epoxy composite and titanium in order to assess the feasibility of titanium as a viable candidate for erosion shielding. Experiment results showed that carbon-fiber epoxy composite showed a brittle erosion behavior, whereas titanium showed a ductile erosion mode. The erosion rate on composite was 1.5 times of that on titanium at impingement angle 15° and increased to 5 times at impact angle 90°.

  14. Optimization of circular plate separators with cross flow for removal of oil droplets and solid particles.

    PubMed

    Ngu, Hei; Wong, Kien Kuok; Law, Puong Ling

    2012-04-01

    A circular gravity-phase separator using coalescing medium with cross flow was developed to remove oil and suspended solids from wastewaters. Coalescence medium in the form of inclined plates promotes rising of oil droplets through coalescence and settling of solid particles through coagulation. It exhibits 22.67% higher removal of total suspended solids (TSS) compared to separators without coalescing medium. Moreover, it removed more than 70% of oil compared to conventional American Petroleum Institute separators, which exhibit an average of 33% oil removal. The flowrate required to attain an effluent oil concentration of 10 mg/L (Q(o10)) at different influent oil concentrations (C(io)) can be represented by Q(o10) x 10(-5) = -0.0012C(io) + 0.352. The flowrate required to attain an effluent TSS concentration of 50 mg/L (Q(ss50)) at different influent TSS concentrations (C(iss)) can be represented by Q(ss50) x 10(-5) = 1.0 x 10(6) C(iss)(-2.9576). The smallest removable solid particle size was 4.87 microm. PMID:22834217

  15. Hybrid sensor for metal grade measurement of a falling stream of solid waste particles

    SciTech Connect

    Abdur Rahman, Md. Bakker, M.C.M.

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer A new sensor system is developed for metal grade measurement of falling bottom ash particles. Black-Right-Pointing-Pointer The system is hybrid, consisting of an optical and an electromagnetic sensor. Black-Right-Pointing-Pointer Grade of ECS concentrated bottom ash in 1-6 mm sieve size accurately measured up to 143 p/s feed rate. Black-Right-Pointing-Pointer Accuracy reached was 2.4% with respect to manual analysis. Black-Right-Pointing-Pointer Measures for elimination of both stationary and stochastic errors are discussed. - Abstract: A hybrid sensor system for accurate detection of the metal grade of a stream of falling solid waste particles is investigated and experimentally verified. The system holds an infrared and an electromagnetic unit around a central tube and counts all the particles and only the metal particles, respectively. The count ratio together with the measured average particle mass ratio (k) of non-metal and metal particles is sufficient for calculation of grade. The performance of the system is accurately verified using synthetic mixtures of sand and metal particles. Towards an application a case study is performed using municipal solid waste incineration bottom ash in size fractions 1-6 mm, which presents a major challenge for nonferrous metal recovery. The particle count ratio was inherently accurate for particle feed rates up to 13 per second. The average value and spread of k for bottom ash was determined as 0.49 {+-} 0.07 and used to calculate grade within 2.4% from the manually analysed grade. At higher feed rates the sensors start missing particles which fall simultaneously through the central tube, but the hybrid system still counted highly repeatable. This allowed for implementation of a count correction ratio to eliminate the stationary error. In combination with averaging in measurement intervals for suppression of stochastic variations the hybrid system regained its accuracy for particle feed

  16. A smooth dissipative particle dynamics method for domains with arbitrary-geometry solid boundaries

    NASA Astrophysics Data System (ADS)

    Gatsonis, Nikolaos A.; Potami, Raffaele; Yang, Jun

    2014-01-01

    A smooth dissipative particle dynamics method with dynamic virtual particle allocation (SDPD-DV) for modeling and simulation of mesoscopic fluids in wall-bounded domains is presented. The physical domain in SDPD-DV may contain external and internal solid boundaries of arbitrary geometries, periodic inlets and outlets, and the fluid region. The SDPD-DV method is realized with fluid particles, boundary particles, and dynamically allocated virtual particles. The internal or external solid boundaries of the domain can be of arbitrary geometry and are discretized with a surface grid. These boundaries are represented by boundary particles with assigned properties. The fluid domain is discretized with fluid particles of constant mass and variable volume. Conservative and dissipative force models due to virtual particles exerted on a fluid particle in the proximity of a solid boundary supplement the original SDPD formulation. The dynamic virtual particle allocation approach provides the density and the forces due to virtual particles. The integration of the SDPD equations is accomplished with a velocity-Verlet algorithm for the momentum and a Runge-Kutta for the entropy equation. The velocity integrator is supplemented by a bounce-forward algorithm in cases where the virtual particle force model is not able to prevent particle penetration. For the incompressible isothermal systems considered in this work, the pressure of a fluid particle is obtained by an artificial compressibility formulation for liquids and the ideal gas law for gases. The self-diffusion coefficient is obtained by an implementation of the generalized Einstein and the Green-Kubo relations. Field properties are obtained by sampling SDPD-DV outputs on a post-processing grid that allows harnessing the particle information on desired spatiotemporal scales. The SDPD-DV method is verified and validated with simulations in bounded and periodic domains that cover the hydrodynamic and mesoscopic regimes for

  17. The Penetration Behavior of an Annular Gas-Solid Jet Impinging on a Liquid Bath: The Effects of the Density and Size of Solid Particles

    NASA Astrophysics Data System (ADS)

    Chang, J. S.; Sohn, H. Y.

    2012-08-01

    Top-blow injection of a gas-solid jet through a circular lance is used in the Mitsubishi Continuous Smelting Process. One problem associated with this injection is the severe erosion of the hearth refractory below the lances. A new configuration of the lance to form an annular gas-solid jet rather than the circular jet was designed in this laboratory. With this new configuration, the solid particles fed through the center tube leave the lance at a much lower velocity than the gas, and the penetration behavior of the jet is significantly different from that with a circular lance where the solid particles leave the lance at the same high velocity as the gas. In previous cold-model investigations in this laboratory, the effects of the gas velocity, particle feed rate, lance height of the annular lance, and the cross-sectional area of the gas jet were studied and compared with the circular lance. This study examined the effect of the density and size of the solid particles on the penetration behavior of the annular gas-solid jet, which yielded some unexpected results. The variation in the penetration depth with the density of the solid particles at the same mass feed rate was opposite for the circular lance and the annular lance. In the case of the circular lance, the penetration depth became shallower as the density of the solid particles increased; on the contrary, for the annular lance, the penetration depth became deeper with the increasing density of particles. However, at the same volumetric feed rate of the particles, the density effect was small for the circular lance, but for the annular lance, the jets with higher density particles penetrated more deeply. The variation in the penetration depth with the particle diameter was also different for the circular and the annular lances. With the circular lance, the penetration depth became deeper as the particle size decreased for all the feed rates, but with the annular lance, the effect of the particle size was

  18. Large-eddy simulation of a solid-particles suspension in a turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Rahman, Mustafa; Samtaney, Ravi

    2014-11-01

    We decribe a framework for the large-eddy simulation of solid particles suspended and transported within an incompressible turbulent boundary layer. The underlying approach to simulate the solid-particle laden flow is Eulerian-Eulerian in which the particles are characterized by statistical descriptors. For the fluid phase, the large-eddy simulation (LES) of incompressible turbulent boundary layer employs stretched spiral vortex subgrid-scale model and a virtual wall model similar to the work of Inoue & Pullin (J. Fluid Mech. 2011). Furthermore, a recycling method to generate turbulent inflow is implemented. For the particle phase, the direct quadrature method of moments (DQMOM) is chosen in which the weights and abscissas of the quadrature approximation are tracked directly rather than the moments themselves. The numerical method in this framework is based on a fractional-step method with an energy-conservative fourth-order finite difference scheme on a staggered mesh. It is proposed to utilize this framework to examine transport of sand in desert sandstorms. Supported by KAUST OCRF funded CRG project on simulation of sandstorms.

  19. Particle size distribution of suspended solids in the Chesapeake Bay entrance and adjacent shelf waters

    NASA Technical Reports Server (NTRS)

    Byrnes, M. R.; Oertel, G. F.

    1981-01-01

    Characteristics of suspended solids, including total suspended matter, total suspended inorganics, total suspended organics, particle size distribution, and the presence of the ten most prominent particle types were determined. Four research vessels simultaneously collected samples along four transects. Samples were collected within a 2-hour period that coincided with the maximum ebb penetration of Chesapeake Bay outwelling. The distribution of primary and secondary particle size modes indicate the presence of a surface or near-surface plume, possibly associated with three sources: (1) runoff, (2) resuspension of material within the Bay, and/or (3) resuspension of material in the area of shoals at the Bay mouth. Additional supportive evidence for this conclusion is illustrated with ocean color scanner data.

  20. Particle size of solid food after human mastication and in vitro simulation of oral breakdown.

    PubMed

    Hoebler, C; Devaux, M F; Karinthi, A; Belleville, C; Barry, J L

    2000-09-01

    Mastication, the first step in food digestion, results in the breakdown of solid food and its lubrication with saliva. Although the rate and extent of starch digestion are closely dependent on the way food is chewed, this factor has not been adequately considered in the preparation of food for in vitro digestion experiments. The purpose of this study was to determine the size distribution of starchy food particles before swallowing and to use an in vitro mincing procedure to simulate how food is divided up during chewing. Foods differing in texture and size (bread, spaghetti and tortiglioni) were chewed by 12 healthy subjects and spat out before swallowing. Chewing time and saliva impregnation were measured for each mouthful. The particle sizes resulting from experiments with chewed and minced bread and pasta were analysed respectively by light laser diffraction and image analysis. Chewing time was longer for bread than pasta, resulting in higher saliva impregnation. Chewed bread showed a bimodal distribution of particle size (30 microns, 500 microns), whereas both kinds of pasta produced particles of similar size (0.5 to 30 mm2) after mastication. Mincing reproduced the division of bread and pasta as achieved by chewing in an acceptable way. From our results it seems that the size of particles resulting from mastication depends on food texture. We succeeded by wetting and mincing food to prepare food in a similar bolus-like form before swallowing. Mincing provides a simple means of simulating the reduction of food into particles for in vitro digestion studies.

  1. DIESEL EXHAUST PARTICLES INDUCE ABERRANT ALVEOLAR EPITHELIAL DIRECTED CELL MOVEMENT BY DISRUPTION OF POLARITY MECHANISMS

    EPA Science Inventory

    Disruption of the respiratory epithelium contributes to the progression of a variety of respiratory diseases that are aggravated by exposure to air pollutants, specifically traffic-based pollutants such as diesel exhaust particles (DEP). Recognizing that lung repair following inj...

  2. Characterisation of solid particles emitted from diesel and petrol engines as a contribution to the determination of the origin of carbonaceous particles in urban aerosol

    NASA Astrophysics Data System (ADS)

    Michalik, M.; Brzeżański, M.; Wilczyńska-Michalik, W.; Fisior, K.; Klimas, B.; Samek, L.; Pietras, B.

    2016-09-01

    Solid particles emitted from diesel and petrol engines were studied using a scanning electron microscope fitted with an energy dispersive spectrometer. The soot emitted from different engines under different operating conditions differed in particle size, and the form and size of aggregates. Identification of the soot particles emitted from diesel or petrol engines in urban aerosol based on their size and morphology was found to be impossible.

  3. Electrical impedance tomography spectroscopy method for characterising particles in solid-liquid phase

    SciTech Connect

    Zhao, Yanlin; Wang, Mi; Yao, Jun

    2014-04-11

    Electrical impedance tomography (EIT) is one of the process tomography techniques to provide an on-line non-invasive imaging for multiphase flow measurement. With EIT measurements, the images of impedance real part, impedance imaginary part, phase angle, and magnitude can be obtained. However, most of the applications of EIT in the process industries rely on the conductivity difference between two phases in fluids to obtain the concentration profiles. It is not common to use the imaginary part or phase angle due to the dominant change in conductivity or complication in the use of other impedance information. In a solid-liquid two phases system involving nano- or submicro-particles, characterisation of particles (e.g. particle size and concentration) have to rely on the measurement of impedance phase angle or imaginary part. Particles in a solution usually have an electrical double layer associated with their surfaces and can form an induced electrical dipole moment due to the polarization of the electrical double layer under the influence of an alternating electric field. Similar to EIT, electrical impedance spectroscopy (EIS) measurement can record the electrical impedance data, including impedance real part, imaginary part and phase angle (θ), which are caused by the polarization of the electrical double layer. These impedance data are related to the particle characteristics e.g. particle size, particle and ionic concentrations in the aqueous medium, therefore EIS method provides a capability for characterising the particles in suspensions. Electrical impedance tomography based on EIS measurement or namely, electrical impedance tomography spectroscopy (EITS) could image the spatial distribution of particle characteristics. In this paper, a new method, including test set-up and data analysis, for characterisation of particles in suspensions are developed through the experimental approach. The experimental results on tomographic imaging of colloidal particles

  4. Electrical impedance tomography spectroscopy method for characterising particles in solid-liquid phase

    NASA Astrophysics Data System (ADS)

    Zhao, Yanlin; Wang, Mi; Yao, Jun

    2014-04-01

    Electrical impedance tomography (EIT) is one of the process tomography techniques to provide an on-line non-invasive imaging for multiphase flow measurement. With EIT measurements, the images of impedance real part, impedance imaginary part, phase angle, and magnitude can be obtained. However, most of the applications of EIT in the process industries rely on the conductivity difference between two phases in fluids to obtain the concentration profiles. It is not common to use the imaginary part or phase angle due to the dominant change in conductivity or complication in the use of other impedance information. In a solid-liquid two phases system involving nano- or submicro-particles, characterisation of particles (e.g. particle size and concentration) have to rely on the measurement of impedance phase angle or imaginary part. Particles in a solution usually have an electrical double layer associated with their surfaces and can form an induced electrical dipole moment due to the polarization of the electrical double layer under the influence of an alternating electric field. Similar to EIT, electrical impedance spectroscopy (EIS) measurement can record the electrical impedance data, including impedance real part, imaginary part and phase angle (θ), which are caused by the polarization of the electrical double layer. These impedance data are related to the particle characteristics e.g. particle size, particle and ionic concentrations in the aqueous medium, therefore EIS method provides a capability for characterising the particles in suspensions. Electrical impedance tomography based on EIS measurement or namely, electrical impedance tomography spectroscopy (EITS) could image the spatial distribution of particle characteristics. In this paper, a new method, including test set-up and data analysis, for characterisation of particles in suspensions are developed through the experimental approach. The experimental results on tomographic imaging of colloidal particles

  5. Particle-wave duality and coherent instability control in dense gas-solid flows.

    SciTech Connect

    Li, J.; Liu, Y. Y.; Decision and Information Sciences

    2008-02-01

    The collective effect of transport behaviors in a multibody system can either drastically enhance or deteriorate system performance depending on the nature of the internal interactions (i.e., constructive or deconstructive) and the structure established. For most powder processes, flow instability leads to poor performance. Control strategies have been attempted previously, but with limited success. The ability to drive such a system that is far from equilibrium into its 'ordered' state by tuning the interactions can effectively reduce internal energy dissipation, which may lead to a technological breakthrough. By using a hybrid dynamics simulation and multiphase flow experiments, we will first elucidate two fundamental mechanisms underlying flow instabilities in a dense gas-solid flow: nonlinear drag and collisional dissipation. Then we clarify how gas-fluidized particles exhibit 'particle-wave' duality (e.g., exhibit standing waves in a thin layer of granular bed that are driven by superimposed oscillating air, when the exciting frequencies of the oscillating air match the system's natural frequency). On this basis, we show experimentally that dense gas-fluidized granules can be synchronized into 'ordered' structures by developing an adaptively exciting fluid wave. The introduction of an additional fluid wave enables the flow structures to be fine-tuned. Our method results in remarkably improved fluidization: highly expanded particulate beds with significantly suppressed gas bubble formation (for coarse particles) and channel formation (for ultra-fine powders), as has always prevailed in conventional dense gas-particle systems. By applying our methodology to several systems that are normally difficult to fluidize, we achieve unprecedented, well-controlled suspension of solids in gas flow. A scientific understanding of complex, dense gas-solid flows should enable the dispersion of solids in the gas flow to be controlled effectively. This work contributes to the

  6. On the high fidelity simulation of chemical explosions and their interaction with solid particle clouds

    NASA Astrophysics Data System (ADS)

    Balakrishnan, Kaushik

    The flow field behind chemical explosions in multiphase environments is investigated using a robust, state-of-the-art simulation strategy that accounts for the thermodynamics, gas dynamics and fluid mechanics of relevance to the problem. Focus is laid on the investigation of blast wave propagation, growth of hydrodynamic instabilities behind explosive blasts, the mixing aspects behind explosions, the effects of afterburn and its quantification, and the role played by solid particles in these phenomena. In particular, the confluence and interplay of these different physical phenomena are explored from a fundamental perspective, and applied to the problem of chemical explosions. A solid phase solver suited for the study of high-speed, two-phase flows has been developed and validated. This solver accounts for the inter-phase mass, momentum and energy transfer through empirical laws, and ensures two-way coupling between the two phases, viz. solid particles and gas. For dense flow fields, i.e., when the solid volume fraction becomes non-negligible (˜60%), the finite volume method with a Godunov type shock-capturing scheme requires modifications to account for volume fraction gradients during the computation of cell interface gas fluxes. To this end, the simulation methodology is extended with the formulation of an Eulerian gas, Lagrangian solid approach, thereby ensuring that the so developed two-phase simulation strategy can be applied for both flow conditions, dilute and dense alike. Moreover, under dense loading conditions the solid particles inevitably collide, which is accounted for in the current research effort with the use of an empirical collision/contact model from literature. Furthermore, the post-detonation flow field consists of gases under extreme temperature and pressure conditions, necessitating the use of real gas equations of state in the multiphase model. This overall simulation strategy is then extended to the investigation of chemical explosions in

  7. Method for producing solid or hollow spherical particles of chosen chemical composition and of uniform size

    DOEpatents

    Hendricks, Charles D.

    1988-01-01

    A method is provided for producing commercially large quantities of high melting temperature solid or hollow spherical particles of a predetermined chemical composition and having a uniform and controlled size distribution. An end (18, 50, 90) of a solid or hollow rod (20, 48, 88) of the material is rendered molten by a laser beam (14, 44, 82). Because of this, there is no possibility of the molten rod material becoming contaminated with extraneous material. In various aspects of the invention, an electric field is applied to the molten rod end (18, 90), and/or the molten rod end (50, 90) is vibrated. In a further aspect of the invention, a high-frequency component is added to the electric field applied to the molten end of the rod (90). By controlling the internal pressure of the rod, the rate at which the rod is introduced into the laser beam, the environment of the process, the vibration amplitude and frequency of the molten rod end, the electric field intensity applied to the molten rod end, and the frequency and intensity of the component added to the electric field, the uniformity and size distribution of the solid or hollow spherical particles (122) produced by the inventive method is controlled. The polarity of the electric field applied to the molten rod end can be chosen to eliminate backstreaming electrons, which tend to produce run-away heating in the rod, from the process.

  8. Many-body dissipative particle dynamics simulation of liquid/vapor and liquid/solid interactions

    SciTech Connect

    Arienti, Marco; Pan, Wenxiao; Li, Xiaoyi; Karniadakis, George E.

    2011-05-27

    The combination of short-range repulsive and long-range attractive forces in Many-body Dissipative Particle Dynamics (MDPD) is examined at a vapor/liquid and liquid/solid interface. Based on the radial distribution of the virial pressure in a drop at equilibrium, a systematic study is carried out to characterize the sensitivity of the surface tension coefficient with respect to the inter-particle interaction parameters. For the first time, this study highlights the approximately cubic dependence of the surface tension coefficient on the bulk density of the fluid. In capillary flow, MDPD solutions are shown to satisfy the condition on the wavelength of an axial disturbance leading to the pinch-off of a cylindrical liquid thread. Correctly, no pinch-off occurs below the cutoff wavelength. MDPD is augmented by a set of bell-shaped weight functions to model interaction with a solid wall. There, hydrophilic and hydrophobic behaviors, including the occurrence of slip in the latter, are reproduced using a modification in the weight function that avoids particle clustering. Finally, the dynamics of droplets entering an inverted Y-shaped fracture junction is correctly captured in simulations parameterized by the Bond number, proving the flexibility of MDPD in modeling interface-dominated flows.

  9. Many-body dissipative particle dynamics simulation of liquid/vapor and liquid/solid interactions

    NASA Astrophysics Data System (ADS)

    Arienti, Marco; Pan, Wenxiao; Li, Xiaoyi; Karniadakis, George

    2011-05-01

    The combination of short-range repulsive and long-range attractive forces in many-body dissipative particle dynamics (MDPD) is examined at a vapor/liquid and liquid/solid interface. Based on the radial distribution of the virial pressure in a drop at equilibrium, a systematic study is carried out to characterize the sensitivity of the surface tension coefficient with respect to the inter-particle interaction parameters. For the first time, the approximately cubic dependence of the surface tension coefficient on the bulk density of the fluid is evidenced. In capillary flow, MDPD solutions are shown to satisfy the condition on the wavelength of an axial disturbance leading to the pinch-off of a cylindrical liquid thread; correctly, no pinch-off occurs below the cutoff wavelength. Moreover, in an example that illustrates the cascade of fluid dynamics behaviors from potential to inertial-viscous to stochastic flow, the dynamics of the jet radius is consistent with the power law predictions of asymptotic analysis. To model interaction with a solid wall, MDPD is augmented by a set of bell-shaped weight functions; hydrophilic and hydrophobic behaviors, including the occurrence of slip in the latter, are reproduced using a modification in the weight function that avoids particle clustering. The dynamics of droplets entering an inverted Y-shaped fracture junction is shown to be correctly captured in simulations parametrized by the Bond number, confirming the flexibility of MDPD in modeling interface-dominated flows.

  10. Measurements of Turbulence Attenuation by a Dilute Dispersion of Solid Particles in Homogeneous Isotropic Turbulence

    NASA Technical Reports Server (NTRS)

    Eaton, John; Hwang, Wontae; Cabral, Patrick

    2002-01-01

    This research addresses turbulent gas flows laden with fine solid particles at sufficiently large mass loading that strong two-way coupling occurs. By two-way coupling we mean that the particle motion is governed largely by the flow, while the particles affect the gas-phase mean flow and the turbulence properties. Our main interest is in understanding how the particles affect the turbulence. Computational techniques have been developed which can accurately predict flows carrying particles that are much smaller than the smallest scales of turbulence. Also, advanced computational techniques and burgeoning computer resources make it feasible to fully resolve very large particles moving through turbulent flows. However, flows with particle diameters of the same order as the Kolmogorov scale of the turbulence are notoriously difficult to predict. Some simple flows show strong turbulence attenuation with reductions in the turbulent kinetic energy by up to a factor of five. On the other hand, some seemingly similar flows show almost no modification. No model has been proposed that allows prediction of when the strong attenuation will occur. Unfortunately, many technological and natural two-phase flows fall into this regime, so there is a strong need for new physical understanding and modeling capability. Our objective is to study the simplest possible turbulent particle-laden flow, namely homogeneous, isotropic turbulence with a uniform dispersion of monodisperse particles. We chose such a simple flow for two reasons. First, the simplicity allows us to probe the interaction in more detail and offers analytical simplicity in interpreting the results. Secondly, this flow can be addressed by numerical simulation, and many research groups are already working on calculating the flow. Our detailed data can help guide some of these efforts. By using microgravity, we can further simplify the flow to the case of no mean velocity for either the turbulence or the particles. In fact

  11. Mathematical modeling of the interaction between an insoluble solid particle and a solidifying interface

    NASA Astrophysics Data System (ADS)

    Catalina, Adrian Vasile

    When a moving solidification front intercepts an insoluble particle, three distinct interaction phenomena can occur: instantaneous engulfment, continuous pushing of the particle, or particle pushing followed by engulfment. Various mathematical models, aiming to predict the critical solidification velocity for the pushing/engulfment transition, have been published in the literature. However, their predictions were not confirmed by the recent experimental measurements performed in microgravity conditions. The aim of this dissertation is to further continue the study of the interaction particle/solidifying interface through mathematical modeling. In this respect, two new analytical models were developed. In addition, a finite difference numerical approach is proposed. The first analytical model, the Equilibrium Breakdown Model, reveals the fact that the particle/solidifying interface interaction is not a steady state process, as assumed in the previously published models. Its simple formulation makes it attractive for practical purposes such as manufacturing of composite materials. The second model, i.e., the Dynamic Model, is more complex and, for the first time, it is able to capture and explain interesting phenomena that escaped the steady state analyses of previously published models. It shows that steady state interaction is only a particular case that can occur only at sub-critical solidification velocity. In this work, both analytical models were successfully validated against experimental data produced under microgravity conditions. The numerical approach, based on an interface tracking procedure, consists in the development of two distinct models, i.e., a solidification model and a fluid flow model. These two models together can give a more comprehensive picture of the particle/interface interaction. The solidification model has the capability to accommodate changes of the solid/liquid interface temperature because of capillarity and solute redistribution. It

  12. Control of processibility by particle size in high energy solid propellants

    SciTech Connect

    Curtis, D.D.

    1987-09-15

    This patent describes a solid propellant comprised on a weight basis of about 15.15% hydroxyl terminated polybutadiene polymer combined with isophorone diisocyanate. About 0.05% carbon black and about 84.8% of a mixture of unground HMX has an average means diameter of about 150 microns and ground HMX, has an average mean diameter of about 8 - 16 microns, wherein the ratio of the ground to unground HMX is from 60:40 to 70:30 by weight and wherein the composite HMX particle size distribution is within various limits.

  13. First results from solid state neutral particle analyzer on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Zhang, J. Z.; Zhu, Y. B.; Zhao, J. L.; Wan, B. N.; Li, J. G.; Heidbrink, W. W.

    2016-11-01

    Full function integrated, compact solid state neutral particle analyzers (ssNPA) based on absolute extreme ultraviolet silicon photodiode have been successfully implemented on the experimental advanced superconducting tokamak to measure energetic particle. The ssNPA system has been operated in advanced current mode with fast temporal and spatial resolution capabilities, with both active and passive charge exchange measurements. It is found that the ssNPA flux signals are increased substantially with neutral beam injection (NBI). The horizontal active array responds to modulated NBI beam promptly, while weaker change is presented on passive array. Compared to near-perpendicular beam, near-tangential beam brings more passive ssNPA flux and a broader profile, while no clear difference is observed on active ssNPA flux and its profile. Significantly enhanced intensities on some ssNPA channels have been observed during ion cyclotron resonant heating.

  14. Numerical Calculation of the Morphology of a Solid/Liquid Interface Near an Insoluble Particle

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Stefanescu, Doru M.; Sen, Subhayu

    2003-01-01

    A numerical mathematical model capable of accurately describing the evolution of the shape of the solid/liquid interface in the proximity of a foreign particle is presented in this paper. The model accounts for the influence of the temperature gradient and the Gibbs-Thomson and disjoining pressure effects. It shows that for the systems characterized by k(sub P) < k(sub L) the disjoining pressure causes the interface curvature to change its sign in the close-contact particle/interface region. It also shows that the increase of the temperature gradient diminishes the effect of the disjoining pressure. Calculated critical solidification velocities for the pushing/engulfment transition are compared with experimental measurements performed in microgravity conditions.

  15. Erosive particle kinematics in the turbulent combustion boundary layer contacting a solid wall

    SciTech Connect

    Buckingham, A.C.; Siekhaus, W.J.

    1983-04-15

    Measurements and numerical modeling are applied to observe and predict the interactive influence of sub-micron gas borne particles in an erosive turbulent combustion wall boundary layer. Some of the experiments and computations discussed are directed to study of turbulent free shear layers. Others ephasize wall boundary layers. The common purpose of all of these studies is to generate information on the particle interaction mechanisms active in alteration and reduction of the turbulent transport and the consequent reduction of the erosive heat and mass transfer. Primary emphasis here is given to analysis of erosive two phase wall boundary layers encountered in solid propellant combustion situations. Examples are gun barrel, rocket nozzle, and coal-fired gas turbine combustion flow fields.

  16. Neutral particle background in cosmic ray telescopes composed of silicon solid state detectors

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Stone, E. C.; Vogt, R. E.

    1977-01-01

    The energy loss-spectrum of secondary charged particles produced by the interaction of gamma-rays and energetic neutrons in silicon solid state detectors has been measured with a satellite-borne cosmic ray telescope. In the satellite measurements presented here two distinct neutral background effects are identified: secondary protons and alpha particles with energies of about 2 to 100 MeV produced by neutron interactions, and secondary electrons with energies of about 0.2 to 10 MeV produced by X-ray interactions. The implications of this neutral background for satellite measurements of low energy cosmic rays are discussed, and suggestions are given for applying these results to other detector systems in order to estimate background contamination and optimize detector system design.

  17. Toluene vapor capture by activated carbon particles in a dual gas-solid cyclone system.

    PubMed

    Lim, Yun Hui; Ngo, Khanh Quoc; Park, Young Koo; Jo, Young Min

    2012-08-01

    Capturing of odorous compounds such as toluene vapor by a particulate-activated carbon adsorbent was investigated in a gas-solid cyclone, which is one type of mobile beds. The test cyclone was early modified with the post cyclone (PoC) and a spiral flow guide to the vortex finder. The proposed process may contribute to the reduction of gases and dust from industrial exhausts, especially when dealing with a low concentration of odorous elements and a large volume ofdust flow. In this device, the toluene capturing efficiency at a 400 ppm concentration rose up to 77.4% when using activated carbon (AC) particles with a median size of 27.03 microm. A maximum 96% of AC particles could be collected for reuse depending on the size and flow rate. The AC regenerated via thermal treatment showed an adsorption potential up to 66.7% throughout repeated tests.

  18. Particle velocity and solid volume fraction measurements with a new capacitive flowmeter at the Solid/Gas Flow Test Facility. [Glass beads

    SciTech Connect

    Bobis, J.P.; Porges, K.G.A.; Raptis, A.C.; Brewer, W.E.; Bernovich, L.T.

    1986-08-01

    The performance of a new capacitive flowmeter has been assessed experimentally in a gas-entrained solid flow stream at the Argonne National Laboratory (ANL) Solid/Gas Flow Test Facility (S/GFTF) for solid feedrates in the range of 0.5 to 2 kg/s and solid-gas loadings up to 22, corresponding to a range of solid volume fractions extending from 0.004 to 0.016. Two types of nonintrusive instruments using the capacitive principle were fabricated at ANL and installed in the horizontal leg of a 12.3 m test section to sense the solids. An improved electrode geometry designed to maximize the coverage of the duct interior while minimizing the readout error due to a nonuniform electric field, was incorporated for one spoolpiece with the sensing electrodes on the outside surface of a ceramic liner and for another spoolpiece with the sensing electrodes mounted flush with the duct inside surface. The capacitive instruments measured the solid volume fraction and the average particle velocity. The results are compared with time-of-flight measurements of short-lived radioactive particles that duplicate closely the size and density of the 1000..mu.. glass beads used in these flow tests. Results show that the solid volume fraction measurements agree with the theoretical models presented and that the particle velocity deduced from the cross-correlation scheme agreed to within 5% of the irradiated particle velocity technique for the 21 to 31 m/s range generated with the S/GFTF. 43 refs., 36 figs., 19 tabs.

  19. Direct measurement of particle size and 3D velocity of a gas-solid pipe flow with digital holographic particle tracking velocimetry.

    PubMed

    Wu, Yingchun; Wu, Xuecheng; Yao, Longchao; Gréhan, Gérard; Cen, Kefa

    2015-03-20

    The 3D measurement of the particles in a gas-solid pipe flow is of great interest, but remains challenging due to curved pipe walls in various engineering applications. Because of the astigmatism induced by the pipe, concentric ellipse fringes in the hologram of spherical particles are observed in the experiments. With a theoretical analysis of the particle holography by an ABCD matrix, the in-focus particle image can be reconstructed by the modified convolution method and fractional Fourier transform. Thereafter, the particle size, 3D position, and velocity are simultaneously measured by digital holographic particle tracking velocimetry (DHPTV). The successful application of DHPTV to the particle size and 3D velocity measurement in a glass pipe's flow can facilitate its 3D diagnostics.

  20. Plume Particle Collection and Sizing from Static Firing of Solid Rocket Motors

    NASA Technical Reports Server (NTRS)

    Sambamurthi, Jay K.

    1995-01-01

    Thermal radiation from the plume of any solid rocket motor, containing aluminum as one of the propellant ingredients, is mainly from the microscopic, hot aluminum oxide particles in the plume. The plume radiation to the base components of the flight vehicle is primarily determined by the plume flowfield properties, the size distribution of the plume particles, and their optical properties. The optimum design of a vehicle base thermal protection system is dependent on the ability to accurately predict this intense thermal radiation using validated theoretical models. This article describes a successful effort to collect reasonably clean plume particle samples from the static firing of the flight simulation motor (FSM-4) on March 10, 1994 at the T-24 test bed at the Thiokol space operations facility as well as three 18.3% scaled MNASA motors tested at NASA/MSFC. Prior attempts to collect plume particles from the full-scale motor firings have been unsuccessful due to the extremely hostile thermal and acoustic environment in the vicinity of the motor nozzle.

  1. Plume particle collection and sizing from static firing of solid rocket motors

    NASA Technical Reports Server (NTRS)

    Sambamurthi, Jay K.

    1995-01-01

    A unique dart system has been designed and built at the NASA Marshall Space Flight Center to collect aluminum oxide plume particles from the plumes of large scale solid rocket motors, such as the space shuttle RSRM. The capability of this system to collect clean samples from both the vertically fired MNASA (18.3% scaled version of the RSRM) motors and the horizontally fired RSRM motor has been demonstrated. The particle mass averaged diameters, d43, measured from the samples for the different motors, ranged from 8 to 11 mu m and were independent of the dart collection surface and the motor burn time. The measured results agreed well with those calculated using the industry standard Hermsen's correlation within the standard deviation of the correlation . For each of the samples analyzed from both MNASA and RSRM motors, the distribution of the cumulative mass fraction of the plume oxide particles as a function of the particle diameter was best described by a monomodal log-normal distribution with a standard deviation of 0.13 - 0.15. This distribution agreed well with the theoretical prediction by Salita using the OD3P code for the RSRM motor at the nozzle exit plane.

  2. Atmospheric Solids Analysis Probe Mass Spectrometry: A New Approach for Airborne Particle Analysis

    SciTech Connect

    Bruns, Emily A.; Perraud, Veronique M.; Greaves, John; Finlayson-Pitts, Barbara J.

    2010-07-15

    Secondary organic aerosols (SOA) formed in the atmosphere from the condensation of semivolatile oxidation products are a significant component of airborne particles which have deleterious effects on health, visibility, and climate. In this study, atmospheric solids analysis probe mass spectrometry (ASAP-MS) is applied for the first time to the identification of organics in particles from laboratory systems as well as from ambient air. SOA were generated in the laboratory from the ozonolysis of r-pinene and isoprene, as well as from NO3 oxidation of r-pinene, and ambient air was sampled at forested and suburban sites. Particles were collected by impaction on ZnSe disks, analyzed by Fourier transform-infrared spectroscopy (FT-IR) and then transferred to an ASAP-MS probe for further analysis. ASAP-MS data for the laboratory-generated samples show peaks from wellknown products of these reactions, and higher molecular weight oligomers are present in both laboratory and ambient samples. Oligomeric products are shown to be present in the NO3 reaction products for the first time. A major advantage of this technique is that minimal sample preparation is required, and complementary information from nondestructive techniques such as FT-IR can be obtained on the same samples. In addition, a dedicated instrument is not required for particle analysis. This work establishes that ASAP-MS will be useful for identification of organic components of SOA in a variety of field and laboratory studies.

  3. Large-eddy simulation of zero-pressure-gradient turbulent boundary layer with solid particle suspension

    NASA Astrophysics Data System (ADS)

    Rahman, Mustafa; Samtaney, Ravi

    2015-11-01

    We present results of solid particles suspension and transport in a fully-developed turbulent boundary layer flow using large-eddy simulation of the incompressible Navier-Stokes equations. We adopt the Eulerian-Eulerian approach to simulating particle laden flow with a large number of particles, in which the particles are characterized by statistical descriptors. For the particulate phase, the direct quadrature method of moments (DQMOM) is chosen in which the weights and abscissas of the quadrature approximation are tracked directly rather than the moments themselves. The underlying approach in modeling the turbulence of fluid phase utilizes the stretched spiral vortex subgrid-scale model and a virtual wall model similar to the work proposed by Inoue & Pullin (J. Fluid Mech. 2011). The solver is verified against simple analytical solutions and the computational results are found to be in a good agreement with these. The capability of the new numerical solver will be exercised to investigate turbulent transport of sand in sandstorms. Finally, the adequacy and limitations of the solver will be discussed. Supported by the KAUST Office of Competitive Research Funds under Award No. URF/1/1704-01.

  4. Fine and ultrafine particles generated during fluidized bed combustion of different solid fuels

    SciTech Connect

    Urciuolo, M.; Barone, A.; D'Alessio, A.; Chirone, R.

    2008-12-15

    The paper reports an experimental study carried out with a 110-mm ID fluidized bed combustor focused on the characterization of particulates formation/emission during combustion of coal and non-fossil solid fuels. Fuels included: a bituminous coal, a commercial predried and granulated sludge (GS), a refuse-derived fuel (RDF), and a biomass waste (pine seed shells). Stationary combustion experiments were carried out analyzing the fate of fuel ashes. Fly ashes collected at the combustor exhaust were characterized both in terms of particle size distribution and chemical composition, with respect to both trace and major elements. Tapping-Mode Atomic Force Microscopy (TM-AFM) technique and high-efficiency cyclone-type collector devices were used to characterize the size and morphology of the nanometric-and micronic-size fractions of fly ash emitted at the exhaust respectively. Results showed that during the combustion process: I) the size of the nanometric fraction ranges between 2 and 65 nm; ii) depending on the fuel tested, combustion-assisted attrition or the production of the primary ash particles originally present in the fuel particles, are responsible of fine particle generation. The amount in the fly ash of inorganic compounds is larger for the waste-derived fuels, reflecting the large inherent content of these compounds in the parent fuels.

  5. Superconducting Solid-State Particle Spectrometers for Atoms and Macromolecules of 3 20 keV

    NASA Astrophysics Data System (ADS)

    Ohkubo, Masataka; Ukibe, Masahiro; Chen, Yiner; Shiki, Shigetomo; Sato, Yuki; Tomita, Shigeo; Hayakawa, Shigeo

    2008-05-01

    Superconducting detectors have no dead surface-layer. It has been found that even if there is a 700 nm-thick SiO2 layer on the sensitive area, the detectors produce measurable output pulses for molecule impact. This feature is very attractive in solid-state spectroscopy of low-energy atoms or molecules for basic chemistry, nuclear physics, and life science. The superconducting tunnel junction detectors enable the measurement of the deposited energy for individual particle impacts in contrast to conventional particle detectors that rely on secondary particle emission. A study of the particle-surface interaction with atoms, proteins, and synthetic polymers has revealed that there are three regions. As the mass value increases, the pulse height reduction, or the decrease of the deposited energy, is remarkable in a mass range below 2,000, the pulse height increases in 2,000 100,000, and finally almost constant pulse height appears in 100,000 1,000,000.

  6. Electrophoresis of a charged colloidal particle in porous media: boundary effect of a solid plane.

    PubMed

    Tsai, Peter; Huang, Cheng-Hsuan; Lee, Eric

    2011-11-15

    Electrokinetic treatments such as the electrophoretic technique have been applied successfully to various soil remediation and contaminant removal situations. To understand further the fundamental features involved, the electrophoretic motion of a charged particle in porous media is investigated theoretically in this study, focusing on the boundary effect of a nearby solid plane toward which the particle moves perpendicularly. The porous medium is modeled as a Brinkman fluid with a characteristic screening length (λ(-1)) that can be obtained directly from the experimental data. General electrokinetic equations are used to describe the system and are solved with a pseudospectral method based on Chebyshev polynomials. We found that the particle motion is deterred by the boundary effect in general. The closer the particle is to the boundary, the more severe this effect is. Up to a 90% reduction in particle mobility is observed in some situations. This indicates that a drastic overestimation (10-fold!) of the overall transport rate of particles may occur for large-scale in situ operations in porous media, such as soil remediation utilizing large planar electrodes, should a portable analytical formula valid for bulk systems only be used. Correction factors for various situations in porous media are presented as convenient charts with which to aid engineers and researchers in the field of environmental engineering, for instance, as a realistic estimation of the actual transport rate obtainable. In addition, the results of present study can be applied to biomedical engineering and drug delivery as well because polymer gels and skin barriers both have a porous essence. PMID:21967511

  7. Diesel exhaust particles induce aberrant alveolar epithelial directed cell movement by disruption of polarity mechanisms.

    PubMed

    LaGier, Adriana J; Manzo, Nicholas D; Dye, Janice A

    2013-01-01

    Disruption of the respiratory epithelium contributes to the progression of a variety of respiratory diseases that are aggravated by exposure to air pollutants, specifically traffic-based pollutants such as diesel exhaust particles (DEP). Recognizing that lung repair following injury requires efficient and directed alveolar epithelial cell migration, this study's goal was to understand the mechanisms underlying alveolar epithelial cells response to DEP, particularly when exposure is accompanied with comorbid lung injury. Separate mechanistic steps of directed migration were investigated in confluent murine LA-4 cells exposed to noncytotoxic concentrations (0-100 μg/cm(2)) of either automobile-emitted diesel exhaust particles (DEP(A)) or carbon black (CB) particles. A scratch wound model ascertained how DEP(A) exposure affected directional cell migration and BCECF ratio fluorimetry-monitored intracellular pH (pHi). Cells were immunostained with giantin to assess cell polarity, and with paxillin to assess focal cell adhesions. Cells were immunoblotted for ezrin/radixin/moesin (ERM) to assess cytoskeletal anchoring. Data demonstrate herein that exposure of LA-4 cells to DEP(A) (but not CB) resulted in delayed directional cell migration, impaired de-adhesion of the trailing edge cell processes, disrupted regulation of pHi, and altered Golgi polarity of leading edge cells, along with modified focal adhesions and reduced ERM levels, indicative of decreased cytoskeletal anchoring. The ability of DEP(A) to disrupt directed cell migration at multiple levels suggests that signaling pathways such as ERM/Rho are critical for transduction of ion transport signals into cytoskeletal arrangement responses. These results provide insights into the mechanisms by which chronic exposure to traffic-based emissions may result in decrements in lung capacity. PMID:23294296

  8. The research on particle trajectory of solid-liquid two-phase flow and erosion predicting in screw centrifugal pump

    NASA Astrophysics Data System (ADS)

    Shen, Z. J.; Li, R. N.; Han, W.; Zhao, W. G.; Wang, X. H.

    2016-05-01

    Use the Discrete Phase Model (DPM) based on Euler-Lagrange method, the internal flow field of screw centrifugal pump was simulated by computational fluid dynamics(CFD) code when transmission medium is solid-liquid two phase flow with large-size particles. The research of liquid phase is under the Euler coordinate system while the solid phase is under the Lagrange coordinate system. The energy change, trajectory characteristic of solid phase particle and its erosion damage rule of solid-phase particle in whole computational domain is analyzed with different density, partical size(d=0.05mm, d=0.2mm, d=2mm) and solid volume fraction(Cv=3%, Cv=5%, Cv=7%).The result shows that within a given diameter range, the low density fine particles trajectory are longer, more collision times with flow passage components, more energy loss and the erosion parts are relatively uniform, but particles which are large-size diameter and high density has a big collision angle with the surface of impeller and volute, even the area of impact and abrasion are quite focus, and easy to be transported. particles will impact with the head of impeller when it enter into impeller domain, the erosion mainly occurs on the work side of impeller.

  9. Numerical simulation on the performance of the vortex pump for transporting solid-liquid two-phase with light particles

    NASA Astrophysics Data System (ADS)

    Mao, W. Y.; Song, P. Y.; Deng, Q. G.; Xu, H. J.

    2016-05-01

    With the purpose of studying performance of the vortex pump for transporting solid-liquid two-phase with light particles whose relative density smaller than 1, the numerical simulation of solid-liquid two phase flowing in the whole channel of a vortex pump with the particle diameter being 0.5 mm, 1 mm, 2 mm, 3 mm and the initial solid phase volume concentrations being 10%, 20% and 30% are respectively carried out by using the commercial software ANSYS Fluent by adopting RNG κ-ɛ turbulent flow model, Eulerian-Eulerian multi-phase flow model and SIMPLEC algorithm. The simulation results show that in the impeller region, the particles concentrate on the non-working surface of the blades, and the particles are rare on the working surface of the blades. As the initial solid phase volume concentration and particle diameter increase, the pump delivery head of vortex pump decrease. The pump delivery head of vortex pump with different initial solid phase concentrations and different particle diameters are predicted and compared with those obtained by an empirical formula, and they shows good agreement.

  10. Effects of process parameters on solid self-microemulsifying particles in a laboratory scale fluid bed.

    PubMed

    Mukherjee, Tusharmouli; Plakogiannis, Fotios M

    2012-01-01

    The purpose of this study was to select the critical process parameters of the fluid bed processes impacting the quality attribute of a solid self-microemulsifying (SME) system of albendazole (ABZ). A fractional factorial design (2(4-1)) with four parameters (spray rate, inlet air temperature, inlet air flow, and atomization air pressure) was created by MINITAB software. Batches were manufactured in a laboratory top-spray fluid bed at 625-g scale. Loss on drying (LOD) samples were taken throughout each batch to build the entire moisture profiles. All dried granulation were sieved using mesh 20 and analyzed for particle size distribution (PSD), morphology, density, and flow. It was found that as spray rate increased, sauter-mean diameter (D(s)) also increased. The effect of inlet air temperature on the peak moisture which is directly related to the mean particle size was found to be significant. There were two-way interactions between studied process parameters. The main effects of inlet air flow rate and atomization air pressure could not be found as the data were inconclusive. The partial least square (PLS) regression model was found significant (P < 0.01) and predictive for optimization. This study established a design space for the parameters for solid SME manufacturing process.

  11. Optimum design of the constant-volume gas pycnometer for determining the volume of solid particles

    NASA Astrophysics Data System (ADS)

    Tamari, S.

    2004-03-01

    Gas pycnometry is based on Boyle-Mariotte's law of volume-pressure relationships. This method has been widely used to determine the volume (and thus the density) of rock fragments, soluble powders, light objects and even living beings. Surprisingly, little is known about the optimum design of gas pycnometers. The purpose of this study was to investigate the optimum design of a gas pycnometer, so that it can determine the volume of solid particles with the greatest accuracy. The 'constant-volume' gas pycnometer was considered because of its widespread use. The law of propagation of uncertainty was used to derive a theoretical formula that relates the pycnometer's accuracy to the main sources of random error (gas-pressure measurements, pycnometer temperature and sample-chamber volume). The consequences of this formula in terms of optimizing the geometry and working conditions of the pycnometer are discussed. It was found that some gas pycnometers described in the literature may have not been used under the best conditions. Guidelines are given to design a gas pycnometer that can theoretically determine the volume of solid particles with a relative standard uncertainty smaller than 0.2%.

  12. A single-camera technique for simultaneous measurement of large solid particles transported in rapid shallow channel flows

    NASA Astrophysics Data System (ADS)

    Tuyen, Nguyen Ba; Cheng, Nian-Sheng

    2012-11-01

    This paper describes a measurement technique that was successfully applied in a study of bed load transport of large spherical solid particles in a shallow and supercritical flow ( Fr = 2.59-3.17) down a steep slope. The experimental condition was characterized by the relatively large solid particle size compared to the flow depth ( d p / h = 0.23-0.35), and compared to the tracer diameter ( d p / d t ≈ 130). The technique incorporated particle image velocimetry and particle tracking velocimetry (PTV) to simultaneously measure the characteristics of the two phases. In order to detect true solid particles and to distinguish them from each other and the unwanted objects, a particle characterization (PCR) algorithm based on Hough transform was employed. The output from the PCR process was utilized for PTV, as well as to generate the corresponding tracer images for special needs. Validation tests have confirmed the pixel accuracy and high reliability of the combined technique. Experimental results obtained with the developed technique include flow velocities, particle velocities, and concentration. The analysis has shown that the particle concentration profile followed an exponential relationship of the form similar to that of Rouse's profiles, despite the large d p / h ratio. It also revealed the effect of phase interaction, as a low loading rate of light particles on the order of O(10-3) could yield a noticeable slowdown in the streamwise fluid velocity.

  13. Meteorological phenomena affecting the presence of solid particles suspended in the air during winter

    NASA Astrophysics Data System (ADS)

    Cariñanos, P.; Galán, C.; Alcázar, P.; Dominguez, E.

    Winter is not traditionally considered to be a risky season for people who suffer from pollen allergies. However, increasing numbers of people are showing symptoms in winter. This prompted our investigation into the levels of solid material in the air, and some of the meteorological phenomena that allow their accumulation. This study showed a possible relationship between the phenomenon of thermal inversion, which occurs when very low temperatures, cloudless skies and atmospheric calms coincide, and an increase in the concentration of solid material in the atmosphere. Frequently, this situation is associated with other predictable phenomena such as fog, dew and frost. This may allow a warning system to be derived for urban pollution episodes. The effect caused by parameters such as wind and rainfall was also analysed. Solid material was differentiated into non-biological material from natural and non-natural sources (e.g. soot, dust, sand, diesel exhaust particles, partially burnt residues) and biological material. The latter mainly comprises pollen grains and fungal spores. Owing to its abundance and importance as a causal agent of winter allergies, Cupressaceae pollen was considered separately.

  14. Meteorological phenomena affecting the presence of solid particles suspended in the air during winter.

    PubMed

    Cariñanos, P; Galán, C; Alcázar, P; Dominguez, E

    2000-05-01

    Winter is not traditionally considered to be a risky season for people who suffer from pollen allergies. However, increasing numbers of people are showing symptoms in winter. This prompted our investigation into the levels of solid material in the air, and some of the meteorological phenomena that allow their accumulation. This study showed a possible relationship between the phenomenon of thermal inversion, which occurs when very low temperatures, cloudless skies and atmospheric calms coincide, and an increase in the concentration of solid material in the atmosphere. Frequently, this situation is associated with other predictable phenomena such as fog, dew and frost. This may allow a warning system to be derived for urban pollution episodes. The effect caused by parameters such as wind and rainfall was also analysed. Solid material was differentiated into non-biological material from natural and non-natural sources (e.g. soot, dust, sand, diesel exhaust particles, partially burnt residues) and biological material. The latter mainly comprises pollen grains and fungal spores. Owing to its abundance and importance as a causal agent of winter allergies, Cupressaceae pollen was considered separately.

  15. Pick-off annihilation of positronium in matter using full correlation single particle potentials: solid He.

    PubMed

    Zubiaga, A; Tuomisto, F; Puska, M J

    2015-01-29

    We investigate the modeling of positronium (Ps) states and their pick-off annihilation trapped at open volumes pockets in condensed molecular matter. Our starting point is the interacting many-body system of Ps and a He atom because it is the smallest entity that can mimic the energy gap between the highest occupied and lowest unoccupied molecular orbitals of molecules, and yet the many-body structure of the HePs system can be calculated accurately enough. The exact-diagonalization solution of the HePs system enables us to construct a pairwise full-correlation single-particle potential for the Ps-He interaction, and the total potential in solids is obtained as a superposition of the pairwise potentials. We study in detail Ps states and their pick-off annihilation rates in voids inside solid He and analyze experimental results for Ps-induced voids in liquid He obtaining the radii of the voids. More importantly, we generalize our conclusions by testing the validity of the Tao-Eldrup model, widely used to analyze ortho-Ps annihilation measurements for voids in molecular matter, against our theoretical results for the solid He. Moreover, we discuss the influence of the partial charges of polar molecules and the strength of the van der Waals interaction on the pick-off annihilation rate. PMID:25523231

  16. Comparison of particle mass and solid particle number (SPN) emissions from a heavy-duty diesel vehicle under on-road driving conditions and a standard testing cycle.

    PubMed

    Zheng, Zhongqing; Durbin, Thomas D; Xue, Jian; Johnson, Kent C; Li, Yang; Hu, Shaohua; Huai, Tao; Ayala, Alberto; Kittelson, David B; Jung, Heejung S

    2014-01-01

    It is important to understand the differences between emissions from standard laboratory testing cycles and those from actual on-road driving conditions, especially for solid particle number (SPN) emissions now being regulated in Europe. This study compared particle mass and SPN emissions from a heavy-duty diesel vehicle operating over the urban dynamometer driving schedule (UDDS) and actual on-road driving conditions. Particle mass emissions were calculated using the integrated particle size distribution (IPSD) method and called MIPSD. The MIPSD emissions for the UDDS and on-road tests were more than 6 times lower than the U.S. 2007 heavy-duty particulate matter (PM) mass standard. The MIPSD emissions for the UDDS fell between those for the on-road uphill and downhill driving. SPN and MIPSD measurements were dominated by nucleation particles for the UDDS and uphill driving and by accumulation mode particles for cruise and downhill driving. The SPN emissions were ∼ 3 times lower than the Euro 6 heavy-duty SPN limit for the UDDS and downhill driving and ∼ 4-5 times higher than the Euro 6 SPN limit for the more aggressive uphill driving; however, it is likely that most of the "solid" particles measured under these conditions were associated with a combination release of stored sulfates and enhanced sulfate formation associated with high exhaust temperatures, leading to growth of volatile particles into the solid particle counting range above 23 nm. Except for these conditions, a linear relationship was found between SPN and accumulation mode MIPSD. The coefficient of variation (COV) of SPN emissions of particles >23 nm ranged from 8 to 26% for the UDDS and on-road tests.

  17. On the behaviour of foreign particles at an advancing solid-liquid interface

    NASA Astrophysics Data System (ADS)

    Pötschke, Jürgen; Rogge, Volker

    1989-03-01

    The present paper describes a theoretical approach to the behaviour at advancing solid-liquid interfaces of foreign particles present in the melt as a separate phase. The temperature field and the influence of a contaminant in the melt were taken into account. The equations which arose were solved numerically. The numerical data can be described with satisfactory accuracy by a function, so that the result can be communicated in the form of a self-contained expression. The use of this equation is found to be in good agreement with recent measurements of latex particles in water: the model gives the critical solidification velocity at which the latex particles of a specific size are only just pushed along by the ice front. An assessment of other measured values given in the literature is not possible since the material values and experimental parameters are not completely known. To consolidate the theory, therefore, further quantitative measurements of systems with known material values, interfacial free energies in particular, are required.

  18. Performance of the solid state neutral particle analyzer array on the national spherical torus experiment

    SciTech Connect

    Liu, D.; Heidbrink, W. W.; Darrow, D. S.; Roquemore, A. L.; Medley, S. S.; Shinohara, K.

    2006-10-15

    The solid state neutral particle analyzer (SSNPA) array on the national spherical torus experiment (NSTX) consists of four chords with tangency radii of 60, 90, 100, and 120 cm that view across the three coinjection neutral beam lines. Each chord utilizes a silicon photodiode that is coupled to fast digitizers to measure the energy distribution of charge exchange fast neutral particles (30-100 keV). By the end of the NSTX 2005 experimental campaign, the electromagnetic noise in the SSNPA was reduced by half and reasonable signals were obtained with good electromagnetic shielding, fast digitization of raw signals, software-based pulse height analysis, and pulse shape discrimination. Energy resolution of {approx}10 keV and time resolution of 2 ms have been achieved. Temporal evolutions of energetic neutral flux obtained with the SSNPA are in good agreement with those obtained with the E(parallel sign)B-type neutral particle analyzer. With these improvements, the SSNPA can be used to study magnetohydrodynamic instabilities and fast ion redistribution. Example data from plasma discharges are presented along with the noise reduction techniques and postshot pulse height analysis methods.

  19. Accelerators for critical experiments involving single-particle upset in solid-state microcircuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1985-01-01

    Charged-particle interactions in microelectronic circuit chips (integrated circuits) present a particularly insidious problem for solid-state electronic systems due to the generation of soft errors or single-particle event upset (SEU) by either cosmic rays or other radiation sources. Particle accelerators are used to provide both light and heavy ions in order to assess the propensity of integrated circuit chips for SEU. Critical aspects of this assessment involve the ability to analytically model SEU for the prediction of error rates in known radiation environments. In order to accurately model SEU, the measurement and prediction of energy deposition in the form of an electron-hole plasma generated along an ion track is of paramount importance. This requires the use of accelerators which allow for ease in both energy control (change of energy) and change of ion species. This and other aspects of ion-beam control and diagnostics (e.g., uniformity and flux) are of critical concern for the experimental verification of theoretical SEU models.

  20. Heat and water transfer in a rotating drum containing solid substrate particles.

    PubMed

    Schutyser, M A I; Weber, F J; Briels, W J; Rinzema, A; Boom, R M

    2003-06-01

    In previous work we reported on the simulation of mixing behavior of a slowly rotating drum for solid-state fermentation (SSF) using a discrete particle model. In this investigation the discrete particle model is extended with heat and moisture transfer. Heat transfer is implemented in the model via interparticle contacts and the interparticle heat transfer coefficient is determined experimentally. The model is shown to accurately predict heat transfer and resulting temperature gradients in a mixed wheat grain bed. In addition to heat transfer, the addition and subsequent distribution of water in the substrate bed is also studied. The water is added to the bed via spray nozzles to overcome desiccation of the bed during evaporative cooling. The development of moisture profiles in the bed during spraying and mixing are studied experimentally with a water-soluble fluorescent tracer. Two processes that affect the water distribution are considered in the model: the intraparticle absorption process, and the interparticle transfer of free water. It is found that optimum distribution can be achieved when the free water present at the surface of the grains is quickly distributed in the bed, for example, by fast mixing. Alternatively, a short spraying period, followed by a period of mixing without water addition, can be applied. The discrete particle model developed is used successfully to examine the influence of process operation on the moisture distribution (e.g., fill level and rotation rate). It is concluded that the extended discrete particle model can be used as a powerful predictive tool to derive operating strategies and criteria for design and scale-up for mixed SSF and other processes with granular media. PMID:12652479

  1. The Role of Cohesive Particle Interactions on Solids Uniformity and Mobilization During Jet Mixing: Testing Recommendations

    SciTech Connect

    Gauglitz, Phillip A.; Wells, Beric E.; Bamberger, Judith A.; Fort, James A.; Chun, Jaehun; Jenks, Jeromy WJ

    2010-04-01

    Radioactive waste that is currently stored in large underground tanks at the Hanford Site will be staged in selected double-shell tanks (DSTs) and then transferred to the Waste Treatment and Immobilization Plant (WTP). Before being transferred, the waste will be mixed, sampled, and characterized to determine if the waste composition and meets the waste feed specifications. Washington River Protection Solutions is conducting a Tank Mixing and Sampling Demonstration Program to determine the mixing effectiveness of the current baseline mixing system that uses two jet mixer pumps and the adequacy of the planned sampling method. The overall purpose of the demonstration program is to mitigate the technical risk associated with the mixing and sampling systems meeting the feed certification requirements for transferring waste to the WTP.The purpose of this report is to analyze existing data and evaluate whether scaled mixing tests with cohesive simulants are needed to meet the overall objectives of the small-scale mixing demonstration program. This evaluation will focus on estimating the role of cohesive particle interactions on various physical phenomena that occur in parts of the mixing process. A specific focus of the evaluation will be on the uniformity of suspended solids in the mixed region. Based on the evaluation presented in this report and the absence of definitive studies, the recommendation is to conduct scaled mixing tests with cohesive particles and augment the initial testing with non-cohesive particles. In addition, planning for the quantitative tests would benefit from having test results from some scoping experiments that would provide results on the general behavior when cohesive inter-particle forces are important.

  2. All about Solids, Liquids & Gases. Physical Science for Children[TM]. Schlessinger Science Library. [Videotape].

    ERIC Educational Resources Information Center

    2000

    In All About Solids, Liquids and Gases, young students will be introduced to the three common forms of matter. They'll learn that all things are made up of tiny particles called atoms and that the movement of these particles determines the form that matter takes. In solids, the particles are packed tightly together and move very little. The…

  3. 3-D imaging of particle tracks in solid state nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2010-05-01

    It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.

  4. Analytic study of heat transfer with variable viscosity on solid particle motion in dusty Jeffery fluid

    NASA Astrophysics Data System (ADS)

    Bhatti, M. M.; Zeeshan, A.

    2016-06-01

    In this paper, effects of variable viscosity with heat transfer on solid particle motion of dusty Jeffrey fluid model through a planar channel has been examined. The governing flow problem for fluid phase and dusty phase is formulated with the help of momentum and energy equation. The resulting coupled ordinary differential equations have been solved analytically and closed form solutions are presented. The influence of all the physical parameters are sketched for velocity profile, pressure rise and temperature profile. Numerical computation is used to evaluate the expression for pressure rise. The present analysis is also presented for Newtonian fluid by taking λ1 → 0 as a special case of our study. It is found that due to the influence of variable viscosity, the fluid velocity changes in the center of the channel and shows opposite behavior near the walls. It is also found that temperature profile increases for larger values of Prandtl number (Pr) and Eckert number (Ec).

  5. Interaction of SiC particles with moving solid-liquid interface during directional solidification of silicon

    NASA Astrophysics Data System (ADS)

    Friedrich, J.; Reimann, C.; Jauss, T.; Cröll, A.; Sorgenfrei, T.

    2016-08-01

    In this work, the interaction of SiC particles, having sizes of 7 μm to 300 μm, with the moving solid-liquid interface during directional solidification of silicon was experimentally and theoretically investigated. This included both convective and nearly diffusive conditions. In the nearly diffusive regime under microgravity, the particles were incorporated at a lower growth velocity than in the convective regime under 1g conditions. The experimental data were compared to simple theoretical models allowing the calculation of the critical growth velocity for the incorporation of spherical particles in dependence of the particle size. It was found that the theoretical results could qualitatively explain the experimental observations when a proper set of equations for the forces acting on the particle and of the material constants are chosen. It can be concluded that sedimentation of the particles due to gravity seems to play a role only for large particles. On the other hand, melt flow might cause a lift force which would push the particles away from the solid-liquid interface, and thus would result in higher critical growth velocities under convective conditions, e.g. due to buoyancy convection. Therefore, a contribution of the missing lift force under μg conditions could lead to the smaller critical growth velocity for particle incorporation that is observed under microgravity.

  6. Comparative studies of magnetic particle-based solid phase fluorogenic and electrochemiluminescent immunoassay.

    PubMed

    Yu, H

    1998-09-01

    Two solid phase immunoassays, an electrochemiluminescent immunoassay (ECLIA) and a magnetic particle fluorogenic immunoassay (MPFIA) were evaluated and compared for bacterial detection. Briefly, the ECLIA is based on a redox reaction between ruthenium (II)-trisbipyridyl Ru[(bpy)3]2+ labeled antibody and the excess of tripropylamine, which generates photons. The entire reaction is carried on the near surface area between the spherical magnetic beads and an anode electrode. The detectable bacterial spores are at a linear range from 5 x 10(3) to 5 x 10(5) colony forming units (cfu) of Bacillus subtilis var. niger spores, 10(2) to 10(4) cfu of Bacillus anthrax spores and 10(2) to 10(6) cells of Escherichia coli O157:H7 in ECLIA. The unique MPFIA technique employs antibody-coated magnetic beads as solid phase in suspension for bacterial capture and concentration in a 96-well microplate format. Primary capturing antibodies, bacteria form a sandwich with alkaline phosphatase (AP)-labeled antibodies as reporter followed by a reaction with the AP substrate, AttoPhos to generate fluorescence for detection. Immunomagnetic separation permits direct isolating and concentrating bacterial cells from the crude samples, such as blood and environmental water. The results of MPFIA for detecting bacteria showed less sensitivity compared with that of ECLIA, however it provides a means for direct, high throughput screening bacteria from crude biological samples. Both ECLIA and MPFIA are rapid (less than one hour) and easy to use.

  7. Impact of surfactants on the crystallization of aqueous suspensions of celecoxib amorphous solid dispersion spray dried particles.

    PubMed

    Chen, Jie; Ormes, James D; Higgins, John D; Taylor, Lynne S

    2015-02-01

    Amorphous solid dispersions are frequently prepared by spray drying. It is important that the resultant spray dried particles do not crystallize during formulation, storage, and upon administration. The goal of the current study was to evaluate the impact of surfactants on the crystallization of celecoxib amorphous solid dispersions (ASD), suspended in aqueous media. Solid dispersions of celecoxib with hydroxypropylmethylcellulose acetate succinate were manufactured by spray drying, and aqueous suspensions were prepared by adding the particles to acidified media containing various surfactants. Nucleation induction times were evaluated for celecoxib in the presence and absence of surfactants. The impact of the surfactants on drug and polymer leaching from the solid dispersion particles was also evaluated. Sodium dodecyl sulfate and Polysorbate 80 were found to promote crystallization from the ASD suspensions, while other surfactants including sodium taurocholate and Triton X100 were found to inhibit crystallization. The promotion or inhibition of crystallization was found to be related to the impact of the surfactant on the nucleation behavior of celecoxib, as well as the tendency to promote leaching of the drug from the ASD particle into the suspending medium. It was concluded that surfactant choice is critical to avoid failure of amorphous solid dispersions through crystallization of the drug.

  8. Experimental determination of the particle sizes in a subscale motor for application to the Ariane 5 solid rocket booster

    NASA Astrophysics Data System (ADS)

    Traineau, J. C.; Kuentzmann, P.; Prevost, M.; Tarrin, P.; Delfour, A.

    The knowledge of the aluminum oxide particle size distribution inside the combustion chamber of a solid propellant rocket motor is an important factor for assessing the combustion stability or the slag mass accumulation in the motor. A representative subscale motor for the Ariane 5 P230 Solid Rocket Booster (SRB), in which helium is injected to quench the condensed phase reactions, has been designed and manufactured. Its use for combustion stability purpose has given the aluminum oxide particle size distribution in conditions representative of the actual Ariane 5 SRB. The experimental techniques, optical and particle capturing, have been found to give results in good agreement. A stretched distribution, with particles ranging from 1 micron to 120 microns and a maximum around 45 microns, has been demonstrated.

  9. Quasi-particle corrections to the LSDA+U electronic structure of solid bcc hydrogen

    NASA Astrophysics Data System (ADS)

    Kioupakis, Emmanouil

    2005-03-01

    Quasi-particle calculations within the GW approximation usually start with the LDA electronic structure as mean field solution, which works well for moderately correlated materials. For strongly correlated systems, such as the transition metal oxides, LSDA can give qualitatively wrong ground states, making any further improvement difficult. By starting with the LSDA+U mean field results in the GW approximation calculation of the electron self-energy, we expect to have a better understanding of the quasi-particle properties in these systems. We employ this approach in the study of solid hydrogen, a model system for which previous results exist in the literature. This will test the applicability of the technique to more realistic systems. This work was supported by National Science Foundation Grant No. DMR04-39768 and by the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, U.S. Department of Energy under Contract No. DE-AC03-76SF00098. Computational resources have been provided by NSF at the National Partnership for Advanced Computational Infrastructure (NPACI) and DOE at the National Energy Research Scientific Computing Center (NERSC)

  10. Planetesimal Growth through the Accretion of Small Solids: Hydrodynamics Simulations with Gas-Particle Coupling

    NASA Astrophysics Data System (ADS)

    Hughes, Anna; Boley, Aaron C.

    2016-10-01

    The growth and migration of planetesimals in young protoplanetary disks are fundamental to the planet formation process. A number of mechanisms seemingly inhibit small grains from growing to sizes much larger than a centimeter, limiting planetesimal growth. In spite of this, the meteoritic record, abundance of exoplanets, and the lifetimes of disks considered altogether indicate that growth must be rapid and common. If a small number of 100-km sized planetesimals do form by some method such as the streaming instability, then gas drag effects could enable those objects to accrete small solids efficiently. In particular, accretion rates for such planetesimals could be higher or lower than rates based on the geometric cross-section and gravitational focusing alone. The local gas conditions and properties of accreting bodies select a locally optimal accretion size for the pebbles. As planetesimals accrete pebbles, they feel an additional angular momentum exchange - causing the planetesimal to slowly drift inward, which becomes significant at short orbital periods. We present self-consistent hydrodynamic simulations with direct particle integration and gas-drag coupling to evaluate the rate of planetesimal growth due to pebble accretion. We explore a range of particle sizes, planetesimal properties, and disk conditions using wind tunnel simulations. These results are followed by numerical analysis of planetesimal drift rates at a variety of stellar distances.

  11. Design and modelling of solidly mounted resonators for low-cost particle sensing

    NASA Astrophysics Data System (ADS)

    Helue Villa-López, Farah; Rughoobur, Girish; Thomas, Sanju; Flewitt, Andrew J.; Cole, Marina; Gardner, Julian W.

    2016-02-01

    This work presents the design and fabrication of Solidly Mounted Resonator (SMR) devices for the detection of particulate matter (PM2.5 and PM10) in order to develop a smart low-cost particle sensor for air quality. These devices were designed to operate at a resonant frequency of either 870 MHz or 1.5 GHz, employing zinc oxide as the piezoelectric layer and an acoustic mirror made from molybdenum and silicon dioxide layers. Finite element analysis of the acoustic resonators was performed using COMSOL Multiphysics software in order to evaluate the frequency response of the devices and the performance of the acoustic mirror. The zinc oxide based acoustic resonators were fabricated on a silicon substrate using a five mask process. The mass sensitivity of the acoustic resonators was estimated using a 3D finite element model and preliminary testing has been performed. The theoretical and observed mass sensitivity were similar at ca. 145 kHz ng-1 for the 870 MHz resonator when detecting PM2.5 suggesting that SMR devices have potential to be used as part of a miniature smart sensor system for airborne particle detection.

  12. 3D imaging of particle tracks in Solid State Nuclear Track Detectors

    NASA Astrophysics Data System (ADS)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2009-04-01

    Inhalation of radon gas (222Rn) and associated ionizing decay products is known to cause lung cancer in human. In the U.K., it has been suggested that 3 to 5 % of total lung cancer deaths can be linked to elevated radon concentrations in the home and/or workplace. Radon monitoring in buildings is therefore routinely undertaken in areas of known risk. Indeed, some organisations such as the Radon Council in the UK and the Environmental Protection Agency in the USA, advocate a ‘to test is best' policy. Radon gas occurs naturally, emanating from the decay of 238U in rock and soils. Its concentration can be measured using CR?39 plastic detectors which conventionally are assessed by 2D image analysis of the surface; however there can be some variation in outcomes / readings even in closely spaced detectors. A number of radon measurement methods are currently in use (for examples, activated carbon and electrets) but the most widely used are CR?39 solid state nuclear track?etch detectors (SSNTDs). In this technique, heavily ionizing alpha particles leave tracks in the form of radiation damage (via interaction between alpha particles and the atoms making up the CR?39 polymer). 3D imaging of the tracks has the potential to provide information relating to angle and energy of alpha particles but this could be time consuming. Here we describe a new method for rapid high resolution 3D imaging of SSNTDs. A ‘LEXT' OLS3100 confocal laser scanning microscope was used in confocal mode to successfully obtain 3D image data on four CR?39 plastic detectors. 3D visualisation and image analysis enabled characterisation of track features. This method may provide a means of rapid and detailed 3D analysis of SSNTDs. Keywords: Radon; SSNTDs; confocal laser scanning microscope; 3D imaging; LEXT

  13. Gas dispersion and immobile gas volume in solid and porous particle biofilter materials at low air flow velocities.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2010-07-01

    Gas-phase dispersion in granular biofilter materials with a wide range of particle sizes was investigated using atmospheric air and nitrogen as tracer gases. Two types of materials were used: (1) light extended clay aggregates (LECA), consisting of highly porous particles, and (2) gravel, consisting of solid particles. LECA is a commercial material that is used for insulation, as a soil conditioner, and as a carrier material in biofilters for air cleaning. These two materials were selected to have approximately the same particle shape. Column gas transport experiments were conducted for both materials using different mean particle diameters, different particle size ranges, and different gas flow velocities. Measured breakthrough curves were modeled using the advection-dispersion equation modified for mass transfer between mobile and immobile gas phases. The results showed that gas dispersivity increased with increasing mean particle diameter for LECA but was independent of mean particle diameter for gravel. Gas dispersivity also increased with increasing particle size range for both media. Dispersivities in LECA were generally higher than for gravel. The mobile gas content in both materials increased with increasing gas flow velocity but it did not show any strong dependency on mean particle diameter or particle size range. The relative fraction of mobile gas compared with total porosity was highest for gravel and lowest for LECA likely because of its high internal porosity. PMID:20681430

  14. Gas dispersion and immobile gas volume in solid and porous particle biofilter materials at low air flow velocities.

    PubMed

    Sharma, Prabhakar; Poulsen, Tjalfe G

    2010-07-01

    Gas-phase dispersion in granular biofilter materials with a wide range of particle sizes was investigated using atmospheric air and nitrogen as tracer gases. Two types of materials were used: (1) light extended clay aggregates (LECA), consisting of highly porous particles, and (2) gravel, consisting of solid particles. LECA is a commercial material that is used for insulation, as a soil conditioner, and as a carrier material in biofilters for air cleaning. These two materials were selected to have approximately the same particle shape. Column gas transport experiments were conducted for both materials using different mean particle diameters, different particle size ranges, and different gas flow velocities. Measured breakthrough curves were modeled using the advection-dispersion equation modified for mass transfer between mobile and immobile gas phases. The results showed that gas dispersivity increased with increasing mean particle diameter for LECA but was independent of mean particle diameter for gravel. Gas dispersivity also increased with increasing particle size range for both media. Dispersivities in LECA were generally higher than for gravel. The mobile gas content in both materials increased with increasing gas flow velocity but it did not show any strong dependency on mean particle diameter or particle size range. The relative fraction of mobile gas compared with total porosity was highest for gravel and lowest for LECA likely because of its high internal porosity.

  15. Particle tracking velocimetry and particle image velocimetry study of the slow motion of rough and smooth solid spheres in a yield-stress fluid.

    PubMed

    Holenberg, Yulia; Lavrenteva, Olga M; Shavit, Uri; Nir, Avinoam

    2012-12-01

    We report experimental evidence of an effect opposite to the "solidification" of small bubbles in liquid where the surface can become immobile. Namely, it is demonstrated that smooth solid spheres falling in a yield-stress fluid under the action of gravity can behave similar to drops. Particle tracking velocimetry was used to determine the shape of the yielded region around solid spherical particles undergoing slow stationary motion in 0.07% w/w Carbopol gel due to gravity under creeping flow conditions. The flow field inside the yielded region was determined by particle image velocimetry. It was found that the shape of the yielded region and the flow field around slow-moving rough particles is similar to the published results of numerical simulations, whereas those around smooth spheres resemble the experimental results obtained for viscous drops. The effect was explained by a slip of the gel on the smooth surface. Most likely, the slip originated from seepage of clean water from the gel, forming a thin lubricating layer near the solid surface.

  16. How long can culturable bacteria and total DNA persist in environmental waters? The role of sunlight and solid particles.

    PubMed

    Gutiérrez-Cacciabue, Dolores; Cid, Alicia G; Rajal, Verónica B

    2016-01-01

    In this work, sunlight inactivation of two indicator bacteria in freshwater, with and without solid particles, was studied and the persistence of culturable cells and total DNA was compared. Environmental water was used to prepare two matrices, with and without solid particles, which were spiked with Escherichia coli and Enterococcus faecalis. These matrices were used to prepare microcosm bags that were placed in two containers: one exposed to sunlight and the other in the dark. During one month, samples were removed from each container and detection was done by membrane filter technique and real-time PCR. Kinetic parameters were calculated to assess sunlight effect. Indicator bacteria without solid particles exposed to sunlight suffered an immediate decay (<4h) compared with the ones which were shielded from them. In addition, the survival of both bacteria with solid particles varied depending on the situation analyzed (T99 from 3 up to 60days), being always culturable E. coli more persistent than E. faecalis. On the other side, E. faecalis DNA persisted much longer than culturable cells (T99>40h in the dark with particles). In this case active cells were more prone to sunlight than total DNA and the protective effect of solid particles was also observed. Results highlight that the effects caused by the parameters which describe the behavior of culturable microorganisms and total DNA in water are different and must be included in simulation models but without forgetting that these parameters will also depend on bacterial properties, sensitizers, composition, type, and uses of the aquatic environment under assessment.

  17. Products of the radical initiated oxidation of model solid and liquid organic acid particles in simulated "clean" and "polluted" environments.

    NASA Astrophysics Data System (ADS)

    Renbaum, L. H.; Smith, G. D.

    2009-05-01

    Using a flow tube reactor coupled to a chemical ionization mass spectrometer, the Cl-initiated oxidation of solid and supercooled liquid organic acid particles were investigated at 293 K. In creating aerosols of species which are able to be supercooled or solid at room temperature, it is possible to distinguish the effect of phase on particle reactivity and product formation. In a clean atmosphere, where there are negligible concentrations of NOx, the primary fate of peroxy radicals (formed from H-abstraction by Cl and OH radicals in the presence of O2) are their reactions to form ketone and alcohol products. These products are then able to undergo further oxidation to form multiply oxidized products. The formation of low-molecular weight volatile species may also be important in the oxidative aging of organic aerosols, however neither the mechanism of their formation nor their formation yields are well understood. We have shown that, for equivalent Cl exposures, more multiply-oxidized species as well as more low-molecular-weight species were created from the oxidation of solid particles than from liquid particles. The findings from these studies suggest that slower diffusion of the oxidation products in solid particles confines them to the surface where they continue to react with Cl radicals producing more-highly- functionalized products which may decompose more readily. By introducing nitric oxide to the flow tube reaction system, we show that in a polluted atmosphere, where NOx is present in significant concentrations, organic nitrate formation may become important on the surface of solid particles but not liquid particles as the RO2 are confined to the surface of solid particles (causing a enhanced localized concentration of RO2) where they may then react with ambient nitric oxide through the reaction RO2 + NO → RO2NO* → RONO2. These experiments of these model systems indicate that particle phase could be important in determining how organic aerosols

  18. Template-Engaged Solid-State Synthesis of Barium Magnesium Silicate Yolk@Shell Particles and Their High Photoluminescence Efficiency.

    PubMed

    Chen, Xuncai; Kim, Woo-Sik

    2016-05-17

    This study presents a new synthetic method for fabricating yolk@shell-structured barium magnesium silicate (BMS) particles through a template-engaged solid-state reaction. First, as the core template, (BaMg)CO3 spherical particles were prepared based on the coprecipitation of Ba(2+) and Mg(2+) . These core particles were then uniformly shelled with silica (SiO2 ) by using CTAB as the structure-directing template to form (BaMg)CO3 @SiO2 particles with a core@shell structure. The (BaMg)CO3 @SiO2 particles were then converted to yolk@shell barium magnesium silicate (BMS) particles by an interfacial solid-state reaction between the (BaMg)CO3 (core) and the SiO2 (shell) at 750 °C. During this interfacial solid-state reaction, Kirkendall diffusion contributed to the formation of yolk@shell BMS particles. Thus, the synthetic temperature for the (BaMg)SiO4 :Eu(3+) phosphor is significantly reduced from 1200 °C with the conventional method to 750 °C with the proposed method. In addition, the photoluminescence intensity of the yolk@shell (BaMg)SiO4 :Eu(3+) phosphor was found to be 9.8 times higher than that of the conventional (BaMg)SiO4 :Eu(3+) phosphor. The higher absorption of excitation light by the structure of the yolk@shell phosphor is induced by multiple light-reflection and -scattering events in the interstitial void between the yolk and the shell. When preparing the yolk@shell (BaMg)SiO4 :Eu(3+) phosphor, a hydrogen environment for the solid-state reaction results in higher photoluminescence efficiency than nitrogen and air environments. The proposed synthetic method can be easily extended to the synthesis of other yolk@shell multicomponent metal silicates.

  19. Geochemically structural characteristics of municipal solid waste incineration fly ash particles and mineralogical surface conversions by chelate treatment.

    PubMed

    Kitamura, Hiroki; Sawada, Takaya; Shimaoka, Takayuki; Takahashi, Fumitake

    2016-01-01

    Leaching behaviors of heavy metals contained in municipal solid waste incineration (MSWI) fly ash have been studied well. However, micro-characteristics of MSWI fly ash particles are still uncertain and might be non-negligible to describe their leaching behaviors. Therefore, this study investigated micro-characteristics of MSWI fly ash particles, especially their structural properties and impacts of chelate treatment on surface characteristics. According to SEM observations, raw fly ash particles could be categorized into four types based on their shapes. Because chelate treatment changed the surface of fly ash particles dramatically owing to secondary mineral formations like ettringite, two more types could be categorized for chelate-treated fly ash particles. Acid extraction experiments suggest that fly ash particles, tested in this study, consist of Si-base insoluble core structure, Al/Ca/Si-base semi-soluble matrices inside the body, and KCl/NaCl-base soluble aggregates on the surface. Scanning electron microscope (SEM) observations of the same fly ash particles during twice moistening treatments showed that KCl/NaCl moved under wet condition and concentrated at different places on the particle surface. However, element mobility depended on secondary mineral formations. When insoluble mineral like gypsum was generated and covered the particle surface, it inhibited element transfer under wet condition. Surface characteristics including secondary mineral formation of MSWI fly ash particles are likely non-negligible to describe trace element leaching behaviors.

  20. Numerical investigation of the flow of ultradisperse particles of the aluminum oxide in the solid-fuel rocket engine nozzle

    NASA Astrophysics Data System (ADS)

    Glazunov, A. A.; Dyachenko, N. N.; Dyachenko, L. I.

    2013-03-01

    The work deals with the two-phase flow investigation. The computations were done for a continuous coagulation model within the framework of the phenomenological multi-fluid model of the medium. A conclusion was drawn that the diminution of the particles size leads to a reduction of two-phase losses in the nozzle unit of the solid-fuel engine.

  1. Development and elaboration of numerical method for simulating gas–liquid–solid three-phase flows based on particle method

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryohei; Mamori, Hiroya; Yamamoto, Makoto

    2016-02-01

    A numerical method for simulating gas-liquid-solid three-phase flows based on the moving particle semi-implicit (MPS) approach was developed in this study. Computational instability often occurs in multiphase flow simulations if the deformations of the free surfaces between different phases are large, among other reasons. To avoid this instability, this paper proposes an improved coupling procedure between different phases in which the physical quantities of particles in different phases are calculated independently. We performed numerical tests on two illustrative problems: a dam-break problem and a solid-sphere impingement problem. The former problem is a gas-liquid two-phase problem, and the latter is a gas-liquid-solid three-phase problem. The computational results agree reasonably well with the experimental results. Thus, we confirmed that the proposed MPS method reproduces the interaction between different phases without inducing numerical instability.

  2. Combustion of single and agglomerated aluminum particles in solid rocket motor flows

    NASA Astrophysics Data System (ADS)

    Melcher, John Charles, IV

    2001-07-01

    Single and agglomerated aluminum droplets were studied in a solid rocket motor (SRM) test chamber with optical access to the internal flow at 6--22 atm and 2300 K. The chamber was pressurized by burning a main grain AP/HTPB propellant, and the burning aluminum droplets were generated by a smaller aluminized solid propellant sample, center-mounted in the flow. A 35 mm camera was used with a chopper wheel to give droplet flame diameter vs. time measurements of the burning droplets in flight, from which bum-rate laws were developed. A high-speed video CCD was used with high-magnification optics in order to image the flame/smoke cloud surrounding the burning liquid droplets. The intensity profiles of the droplet images were de-convoluted using an Abel inversion to give true intensity profiles. Both single and agglomerated droplets were studied, where agglomerates are comprised of hundreds of parent particles or more. The Abel inversion results show that the relative smoke cloud size is not constant with diameter, but instead grows as the droplet shrinks, by ˜D -0.5, for both the single and agglomerated droplets. Measured diameter trajectories show that for single droplets, the diameter law is D 0.75 = DO0.75 = 8·t [mu m, msec], and for agglomerated droplets, D 1.0 = Do1.0 - 20·t, such that the single droplets burn faster than the agglomerates. For both single and agglomerated droplets, the burning rate slope k did not change significantly over the chamber pressure studied. Lastly, a model was developed to describe the oxide cap accumulation on the droplet surface from the oxide smoke cloud surrounding the droplet. Results suggest that less oxide accumulates in high-pressure SRMs when considering mass burning rates for different relative cap sizes. The thermophoretic force, which can control oxide transport only over the cap, decreases with pressure.

  3. Reactions at the solid-liquid interface: surface-controlled dissolution of solid particles. The dissolution of potassium bicarbonate in dimethylformamide.

    PubMed

    Forryan, Claire L; Klymenko, Oleksiy V; Brennan, Colin M; Compton, Richard G

    2005-02-24

    We present a mathematical model for the surface-controlled dissolution of solid particles. This is applied to the dissolution of a solid having different particle size distribution functions: those of a monodispersed solid containing particles of all one size, a two-size-particle distribution, and a Gaussian distribution of the particle sizes. The dissolution of potassium bicarbonate in dimethylformamide is experimentally studied indirectly at elevated temperatures. We monitor the dissolution via the homogeneous deprotonation of 2-cyanophenol by dissolved KHCO3. The loss of 2-cyanophenol was detected electrochemically at a platinum microdisk electrode, and separately, the formation of the 2-cyanophenolate anion was monitored via UV-visible spectroscopic analysis. The results presented show that the kinetics of the loss of 2-cyanophenol behaves on one hand as a homogeneous chemical process and on the other hand as a dissolution-rate-controlled process. Initially, predissolved KHCO3 in solution deprotonates the 2-cyanophenol and homogeneous reaction dominates the observed kinetics, and at longer times, the observed kinetics is controlled by the rate of KHCO3 dissolution. Modeling of the experimental results for the surface-controlled dissolution of KHCO3 in dimethylformamide (DMF) yielded a mean value for the dissolution rate constant, k, at elevated temperatures; k was found to have a value of (1.1 +/- 0.3) x 10(-8) mol cm(-2) s(-1) at 100 degrees C, and the activation energy for the dissolution was 34.4 +/- 0.4 kJ mol(-1) over the temperature range 60-100 degrees C. PMID:16851298

  4. Flow and motion of condensed-phase particles in the prenozzle space of solid-propellant rocket motors

    NASA Astrophysics Data System (ADS)

    Volkov, K. N.; Emel'yanov, V. N.; Kurova, I. V.

    2012-07-01

    The flow of an inviscid liquid containing condensed-phase particles around the recessed nozzle of the solidpropellant rocket motor has been considered. To take into account the complex geometry of the prenozzle space of the rocket motor, the equations describing the liquid flow were written in a curvilinear coordinate system. The paths of solid particles were calculated in the known liquid flow field. The quality criteria of the meshes constructed with the use of different approaches have been compared. The results of the calculations permit determining the limit path of particles dividing the flow region into two subregions, one of which is occupied by particles and the other is free from condensed-phase particles.

  5. Development of Criteria and Identification of Particle Cluster Size Based on Measurements of Void Fraction in Gas-Solid Systems

    SciTech Connect

    David Roelant; Seckin Gokaltun

    2009-06-30

    A circulating fluidized bed (CFB) built at FIU was used to study particle motion in the riser in order to simulate flow regimes in a cold gasifier. High speed imaging was used in order to capture the dynamics of the particles flowing in the riser. The imaging method used here is called the shadow sizing technique which allowed the determination of particle areas and trajectories at various flow rates in the riser. The solid volume fraction and particle velocities calculated using the images acquired during the experiments can be related to granular temperature in order to detect formations of clusters in the riser section of the CFB. The shadow sizing technique was observed to be an effective method in detecting dynamics of particles in motion and formation of clusters when supported with high-speed imaging.

  6. Quantifying solid deformation in wellbore cement with Particle-Image-Velocimetry and X-Ray Tomography

    NASA Astrophysics Data System (ADS)

    Walsh, S. D.; Carroll, S.; Du Frane, W. L.; Mason, H. E.

    2012-12-01

    Particle Image Velocimetry (PIV) is a technique that has been widely employed to study velocity fields in complex fluid flows. In this paper, we describe how PIV methods can be applied to high-resolution X-Ray Computed Tomography (XRCT) of solid samples. Unlike traditional PIV techniques for fluids, the XRCT-PIV method does not rely on introduced tracer particles, but rather uses in-situ sample heterogeneities. As such, the technique provides a non-destructive, non-invasive method for tracking sample deformation. In addition, the use of XRCT allows three dimensional volumes to be compared, rather than the two dimensional images used in traditional PIV. This adds to the robustness of the method, allowing accurate displacements to be obtained despite measurement artifacts or changes in sample mineralogy. In this presentation we demonstrate the use of XRCT-PIV on tomographic images from a study of wellbore-cement integrity in which the cement samples undergo a series of reactions following exposure to carbon-dioxide rich brine. The XRCT-PIV method is used to reveal the deformation that occurs as a result of the mechanical changes in the cement surface. We also verify the precision and robustness of the technique in the presence of noise with tests conducted on numerically-generated virtual samples. The results from both the cement samples and numerical tests reveal that accurate displacement measurements are obtained despite chemical alteration and instrument artifacts. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Modification of heat transfer correlations in a liquid-solid fluidized bed heat exchanger with cylindrical particles in aggregative fluidization

    NASA Astrophysics Data System (ADS)

    Maddahi, M. H.; Hatamipour, M. S.; Jamialahmadi, M.

    2016-11-01

    Most correlations presented for the heat transfer coefficient of liquid-solid fluidized bed heat exchangers are based on experiments with glass bead particles in particulate fluidization which usually under-predict the heat transfer coefficient. The present study used experimental data from previous studies for the heat transfer coefficient in liquid-solid fluidized bed heating systems using cylindrical metal particles and five heat transfer correlations based on experiments with spherical glass beads to approximate the behavior of the cylindrical metal particles under aggregative conditions. The results show that modifying the correlations significantly improved the prediction of heat transfer coefficients and the average relative error decreased in comparison with those for the original correlations.

  8. Study of Heat Transfer with Nonlinear Thermal Radiation on Sinusoidal Motion of Magnetic Solid Particles in a Dusty Fluid

    NASA Astrophysics Data System (ADS)

    Bhatti, M. M.; Zeeshan, A.; Ellahi, R.

    2016-09-01

    In this article, heat transfer with nonlinear thermal radiation on sinusoidal motion of magnetic solid particles in a dust Jeffrey fluid has been studied. The effects of Magnetohydrodynamic (MHD) and hall current are also taken under consideration. The governing equation of motion and energy equation are modelled with help of Ohms law for fluid and dust phases. The solutions of the resulting ordinary coupled partial differential equations are solved analytically. The impact of all the physical parameters of interest such as Hartmann number, slip parameter, Hall parameter, radiation parameter, Prandtl number, Eckert number and particle volume fraction are demonstrated mathematically and graphically. Trapping mechanism is also discussed in detail by drawing contour lines. The present analysis affirms many interesting behaviours, which permit further study on solid particles motion with heat and mass transfer.

  9. Quench-Condensed Microalloyed Particles: a Microscopic View of Solid Solubility and Metastability

    NASA Astrophysics Data System (ADS)

    Lamberti, Vincent Edward

    Solid solubility and metastability in noble-metal and iron-silver alloys have been studied from the perspective of microalloyed particles. Samples were obtained through a novel, gram-scale technique that consisted of cocondensation of two elemental metal vapors with a large excess of inert gas on the reaction surface of a rotating cryostat at 77 K. This technique permitted greater control of both particle size and composition than conventional gas aggregation methods. The chemical and physical characteristics of the microalloys have been elaborated through chemical analysis, x-ray diffraction, electron microscopy, temperature-programmed mass spectrometry, EXAFS, XPS and Moessbauer spectroscopy. Electron microscopy indicated the microstructures of copper-gold and copper-silver microalloys prepared in sulfur hexafluoride to consist of discrete collections of crystallites suspended in amorphous "baths". The average dimensions of the crystallites were <100 A, while the aggregates spanned hundreds of nanometers. The microstructures of both systems were metastable. The EXAFS of a copper-silver microalloy showed it to be stiffer, as well as more disordered, than a homometallic copper product. The EXAFS also showed no detectable Cu-Ag contacts, but suggested the existence (through a "missing-atom" effect) of a large number of disordered copper sites. Moessbauer spectra of an iron -silver microalloy prepared in xenon revealed the presence of a superparamagnetic alloy phase characterized by a blocking temperature of approximately 45 K. Cocondensations of iron vapor with excess sulfur hexafluoride produced ultrafine (dimensions ~ 100 A), amorphous particles that were decorated with a -CF_{2^-} polymer. The formation of the polymer was attributed to reaction of the iron with the matrix and adventitious organic compounds--that is, to activation of S-F and C-H bonds. Matrix isolation experiments indicated that, although inert in their ground-state configuration, photoexcited (4p

  10. Safety and pharmacokinetics of a solid lipid curcumin particle formulation in osteosarcoma patients and healthy volunteers.

    PubMed

    Gota, Vikram S; Maru, Girish B; Soni, Tejal G; Gandhi, Tejal R; Kochar, Nitin; Agarwal, Manish G

    2010-02-24

    Curcumin is the lipid-soluble antioxidant compound obtained from the rhizome of Curcuma longa Linn, also known as turmeric. Curcumin targets multiple chemotherapeutic and inflammatory pathways and has demonstrated safety and tolerability in humans, supporting its potential as a therapeutic agent; however, the clinical literature lacks conclusive evidence supporting its use as a therapeutic agent due to its low bioavailability in humans. The purpose of this study was to quantify plasma levels of free curcumin after dosing of a solid lipid curcumin particle (SLCP) formulation versus unformulated curcumin in healthy volunteers and to determine its tolerability and dose-plasma concentration relationship in late-stage osteosarcoma patients. Doses of 2, 3, and 4 g of SLCP were evaluated in 11 patients with osteosarcoma. Plasma curcumin levels were measured using a validated high-performance liquid chromatography method. The limit of detection of the assay was 1 ng/mL of curcumin. In healthy subjects, the mean peak concentration of curcumin achieved from dosing 650 mg of SLCP was 22.43 ng/mL, whereas plasma curcumin from dosing an equal quantity of unformulated 95% curcuminoids extract was not detected. In both healthy individuals and osteosarcoma patients, high interindividual variability in pharmacokinetics and nonlinear dose dependency was observed, suggesting potentially complex absorption kinetics. Overall, good tolerability was noted in both healthy and osteosarcoma groups. PMID:20092313

  11. A smooth particle hydrodynamics code to model collisions between solid, self-gravitating objects

    NASA Astrophysics Data System (ADS)

    Schäfer, C.; Riecker, S.; Maindl, T. I.; Speith, R.; Scherrer, S.; Kley, W.

    2016-05-01

    Context. Modern graphics processing units (GPUs) lead to a major increase in the performance of the computation of astrophysical simulations. Owing to the different nature of GPU architecture compared to traditional central processing units (CPUs) such as x86 architecture, existing numerical codes cannot be easily migrated to run on GPU. Here, we present a new implementation of the numerical method smooth particle hydrodynamics (SPH) using CUDA and the first astrophysical application of the new code: the collision between Ceres-sized objects. Aims: The new code allows for a tremendous increase in speed of astrophysical simulations with SPH and self-gravity at low costs for new hardware. Methods: We have implemented the SPH equations to model gas, liquids and elastic, and plastic solid bodies and added a fragmentation model for brittle materials. Self-gravity may be optionally included in the simulations and is treated by the use of a Barnes-Hut tree. Results: We find an impressive performance gain using NVIDIA consumer devices compared to our existing OpenMP code. The new code is freely available to the community upon request. If you are interested in our CUDA SPH code miluphCUDA, please write an email to Christoph Schäfer. miluphCUDA is the CUDA port of miluph. miluph is pronounced [maßl2v]. We do not support the use of the code for military purposes.

  12. Safety and pharmacokinetics of a solid lipid curcumin particle formulation in osteosarcoma patients and healthy volunteers.

    PubMed

    Gota, Vikram S; Maru, Girish B; Soni, Tejal G; Gandhi, Tejal R; Kochar, Nitin; Agarwal, Manish G

    2010-02-24

    Curcumin is the lipid-soluble antioxidant compound obtained from the rhizome of Curcuma longa Linn, also known as turmeric. Curcumin targets multiple chemotherapeutic and inflammatory pathways and has demonstrated safety and tolerability in humans, supporting its potential as a therapeutic agent; however, the clinical literature lacks conclusive evidence supporting its use as a therapeutic agent due to its low bioavailability in humans. The purpose of this study was to quantify plasma levels of free curcumin after dosing of a solid lipid curcumin particle (SLCP) formulation versus unformulated curcumin in healthy volunteers and to determine its tolerability and dose-plasma concentration relationship in late-stage osteosarcoma patients. Doses of 2, 3, and 4 g of SLCP were evaluated in 11 patients with osteosarcoma. Plasma curcumin levels were measured using a validated high-performance liquid chromatography method. The limit of detection of the assay was 1 ng/mL of curcumin. In healthy subjects, the mean peak concentration of curcumin achieved from dosing 650 mg of SLCP was 22.43 ng/mL, whereas plasma curcumin from dosing an equal quantity of unformulated 95% curcuminoids extract was not detected. In both healthy individuals and osteosarcoma patients, high interindividual variability in pharmacokinetics and nonlinear dose dependency was observed, suggesting potentially complex absorption kinetics. Overall, good tolerability was noted in both healthy and osteosarcoma groups.

  13. Design of solid state neutral particle analyzer array for National Spherical Torus Experiment-Upgrade

    SciTech Connect

    Liu, D. Heidbrink, W. W.; Zhu, Y. B.; Tritz, K.; Roquemore, A. L.; Medley, S. S.

    2014-11-15

    A new compact, multi-channel Solid State Neutral Particle Analyzer (SSNPA) diagnostic based on silicon photodiode array has been designed and is being fabricated for the National Spherical Torus Experiment-Upgrade (NSTX-U). The SSNPA system utilizes a set of vertically stacked photodiode arrays in current mode viewing the same plasma region with different filter thickness to obtain fast temporal resolution (∼120 kHz bandwidth) and coarse energy information in three bands of >25 keV, >45 keV, and >65 keV. The SSNPA system consists of 15 radial sightlines that intersect existing on-axis neutral beams at major radii between 90 and 130 cm, 15 tangential sightlines that intersect new off-axis neutral beams at major radii between 120 and 145 cm. These two subsystems aim at separating the response of passing and trapped fast ions. In addition, one photodiode array whose viewing area does not intersect any neutral beams is used to monitor passive signals produced by fast ions that charge exchange with background neutrals.

  14. Modeling the Growth of Filamentous Fungi at the Particle Scale in Solid-State Fermentation Systems.

    PubMed

    Sugai-Guérios, Maura Harumi; Balmant, Wellington; Furigo, Agenor; Krieger, Nadia; Mitchell, David Alexander

    2015-01-01

    Solid-state fermentation (SSF) with filamentous fungi is a promising technique for the production of a range of biotechnological products and has the potential to play an important role in future biorefineries. The performance of such processes is intimately linked with the mycelial mode of growth of these fungi: Not only is the production of extracellular enzymes related to morphological characteristics, but also the mycelium can affect bed properties and, consequently, the efficiency of heat and mass transfer within the bed. A mathematical model that describes the development of the fungal mycelium in SSF systems at the particle scale would be a useful tool for investigating these phenomena, but, as yet, a sufficiently complete model has not been proposed. This review presents the biological and mass transfer phenomena that should be included in such a model and then evaluates how these phenomena have been modeled previously in the SSF and related literature. We conclude that a discrete lattice-based model that uses differential equations to describe the mass balances of the components within the system would be most appropriate and that mathematical expressions for describing the individual phenomena are available in the literature. It remains for these phenomena to be integrated into a complete model describing the development of fungal mycelia in SSF systems.

  15. Design of solid state neutral particle analyzer array for National Spherical Torus Experiment-Upgrade

    NASA Astrophysics Data System (ADS)

    Liu, D.; Heidbrink, W. W.; Tritz, K.; Zhu, Y. B.; Roquemore, A. L.; Medley, S. S.

    2014-11-01

    A new compact, multi-channel Solid State Neutral Particle Analyzer (SSNPA) diagnostic based on silicon photodiode array has been designed and is being fabricated for the National Spherical Torus Experiment-Upgrade (NSTX-U). The SSNPA system utilizes a set of vertically stacked photodiode arrays in current mode viewing the same plasma region with different filter thickness to obtain fast temporal resolution (˜120 kHz bandwidth) and coarse energy information in three bands of >25 keV, >45 keV, and >65 keV. The SSNPA system consists of 15 radial sightlines that intersect existing on-axis neutral beams at major radii between 90 and 130 cm, 15 tangential sightlines that intersect new off-axis neutral beams at major radii between 120 and 145 cm. These two subsystems aim at separating the response of passing and trapped fast ions. In addition, one photodiode array whose viewing area does not intersect any neutral beams is used to monitor passive signals produced by fast ions that charge exchange with background neutrals.

  16. Design of solid state neutral particle analyzer array for National Spherical Torus Experiment-Upgrade.

    PubMed

    Liu, D; Heidbrink, W W; Tritz, K; Zhu, Y B; Roquemore, A L; Medley, S S

    2014-11-01

    A new compact, multi-channel Solid State Neutral Particle Analyzer (SSNPA) diagnostic based on silicon photodiode array has been designed and is being fabricated for the National Spherical Torus Experiment-Upgrade (NSTX-U). The SSNPA system utilizes a set of vertically stacked photodiode arrays in current mode viewing the same plasma region with different filter thickness to obtain fast temporal resolution (∼120 kHz bandwidth) and coarse energy information in three bands of >25 keV, >45 keV, and >65 keV. The SSNPA system consists of 15 radial sightlines that intersect existing on-axis neutral beams at major radii between 90 and 130 cm, 15 tangential sightlines that intersect new off-axis neutral beams at major radii between 120 and 145 cm. These two subsystems aim at separating the response of passing and trapped fast ions. In addition, one photodiode array whose viewing area does not intersect any neutral beams is used to monitor passive signals produced by fast ions that charge exchange with background neutrals.

  17. The Apparent Thermal Conductivity of Liquids Containing Solid Particles of Nanometer Dimensions: A Critique

    NASA Astrophysics Data System (ADS)

    Tertsinidou, Georgia; Assael, Marc J.; Wakeham, William A.

    2015-07-01

    There have been conflicting statements in the literature of the last twenty years about the behavior of the apparent thermal conductivity of two- or three-phase systems comprising solid particles with nanometer dimensions suspended in fluids. It has been a feature of much of the work that these multiphase systems have been treated as if a single-phase fluid and that the thermodynamic characteristics of the system have varied even though the systems have been given the same name. These so-called nanofluids have been the subject of a large number of investigations by a variety of different experimental techniques. In the current paper, we critically evaluate the studies of seven of the simplest particulate/fluid systems: Cu, CuO, , and suspended in water and ethylene glycol. Our conclusion is that when results for exactly the same thermodynamic system are obtained with proven experimental techniques, the apparent thermal conductivity of the nanofluid exhibits no behavior that is unexpected and inconsistent with a simple model of conduction in stationary, multiphase systems. The wider variety of behavior that has been reported in the literature for these systems is therefore attributed to ill-characterization of the thermodynamic system and/or the application of experimental techniques of unproven validity.

  18. Impact of Single-Particle Compressibility on the Fluid-Solid Phase Transition for Ionic Microgel Suspensions

    NASA Astrophysics Data System (ADS)

    Pelaez-Fernandez, M.; Souslov, Anton; Lyon, L. A.; Goldbart, P. M.; Fernandez-Nieves, A.

    2015-03-01

    We study ionic microgel suspensions composed of swollen particles for various single-particle stiffnesses. We measure the osmotic pressure π of these suspensions and show that it is dominated by the contribution of free ions in solution. As this ionic osmotic pressure depends on the volume fraction of the suspension ϕ , we can determine ϕ from π , even at volume fractions so high that the microgel particles are compressed. We find that the width of the fluid-solid phase coexistence, measured using ϕ , is larger than its hard-sphere value for the stiffer microgels that we study and progressively decreases for softer microgels. For sufficiently soft microgels, the suspensions are fluidlike, irrespective of volume fraction. By calculating the dependence on ϕ of the mean volume of a microgel particle, we show that the behavior of the phase-coexistence width correlates with whether or not the microgel particles are compressed at the volume fractions corresponding to fluid-solid phase coexistence.

  19. Oxide coating mechanism during fluidized bed reduction: solid-state reaction characteristics between iron ore particles and MgO

    NASA Astrophysics Data System (ADS)

    Guo, Lei; Gao, Jin-tao; Zhong, Yi-wei; Gao, Han; Guo, Zhan-cheng

    2016-09-01

    Experiments on the solid-state reaction between iron ore particles and MgO were performed to investigate the coating mechanism of MgO on the iron ore particles' surface during fluidized bed reduction. MgO powders and iron ore particles were mixed and compressed into briquettes and, subsequently, roasted at different temperatures and for different time periods. A Mg-containing layer was observed on the outer edge of the iron ore particles when the roasting temperature was greater than 1173 K. The concentration of Fe in the Mg-containing layer was evenly distributed and was approximately 10wt%, regardless of the temperature change. Boundary layers of Mg and Fe were observed outside of the iron ore particles. The change in concentration of Fe in the boundary layers was simulated using a gas-solid diffusion model, and the diffusion coefficients of Fe and Mg in these layers at different temperatures were calculated. The diffusion activation energies of Fe and Mg in the boundary layers in these experiments were evaluated to be approximately 176 and 172 kJ/mol, respectively.

  20. Macroscopic yielding in jammed solids is accompanied by a nonequilibrium first-order transition in particle trajectories

    NASA Astrophysics Data System (ADS)

    Kawasaki, Takeshi; Berthier, Ludovic

    2016-08-01

    We use computer simulations to analyze the yielding transition during large-amplitude oscillatory shear of a simple model for soft jammed solids. Simultaneous analysis of global mechanical response and particle-scale motion demonstrates that macroscopic yielding, revealed by a smooth crossover in mechanical properties, is accompanied by a sudden change in the particle dynamics, which evolves from nondiffusive motion to irreversible diffusion as the amplitude of the shear is increased. We provide numerical evidence that this sharp change corresponds to a nonequilibrium first-order dynamic phase transition, thus establishing the existence of a well-defined microscopic dynamic signature of the yielding transition in amorphous materials in oscillatory shear.

  1. MIGRATION OF A MOONLET IN A RING OF SOLID PARTICLES: THEORY AND APPLICATION TO SATURN'S PROPELLERS

    SciTech Connect

    Crida, Aurelien; Papaloizou, John C. B.; Rein, Hanno; Charnoz, Sebastien; Salmon, Julien

    2010-10-15

    Hundred-meter-sized objects have been identified by the Cassini spacecraft in Saturn's A ring through the so-called propeller features they create in the ring. These moonlets should migrate due to their gravitational interaction with the ring; in fact, some orbital variations have been detected. The standard theory of type I migration of planets in protoplanetary disks cannot be applied to the ring system as it is pressureless. Thus, we compute the differential torque felt by a moonlet embedded in a two-dimensional disk of solid particles, with a flat surface density profile, both analytically and numerically. We find that the corresponding migration rate is too small to explain the observed variations of the propeller's orbit in Saturn's A ring. However, local density fluctuations (due to gravity wakes in the marginally gravitationally stable A ring) may exert a stochastic torque on a moonlet. Our simulations show that this torque can be large enough to account for the observations depending on the parameters of the rings. We find that on timescales of several years the migration of propellers is likely to be dominated by stochastic effects (while the former, non-stochastic migration dominates after {approx}10{sup 4}-10{sup 5} years). In that case, the migration rates provided by observations so far suggest that the surface density of the A ring should be on the order of 700 kg m{sup -2}. The age of the propellers should not exceed 1-100 million years depending on the dominant migration regime.

  2. Fundamental study on transient bubble (slug) behavior by characterizing transient forces of solid particles in fluidized beds

    SciTech Connect

    Kono, H.O.

    1991-01-01

    The objective of this work is to recognize and interpret the signals of transient motion of bubbles (slugs) in fluidized beds by measuring and utilizing the signals of transient motion of solid particles. The two signals were measured simultaneously and also synchronized by using the TTL signal technique in the same fluidized beds. Also, a simultaneous study of video bubble image, transient force and pressure signals was initiated in a two dimensional fluidized bed. we successfully synchronized three signals so that the relationship of bubble behavior and force pressure signals can be identified and characterized. It has been found that bubble image can well be correlated to the transient force signal of solid particles under certain conditions in three dimensional fluidized beds. Accordingly, it seems that the transient force signals can significantly help understanding the transient motion of bubbles (slugs), which is important to design the fluidized beds.

  3. Fundamental study on transient bubble (slug) behavior by characterizing transient forces of solid particles in fluidized beds. 1990 Annual report

    SciTech Connect

    Kono, H.O.

    1991-01-01

    The objective of this work is to recognize and interpret the signals of transient motion of bubbles (slugs) in fluidized beds by measuring and utilizing the signals of transient motion of solid particles. The two signals were measured simultaneously and also synchronized by using the TTL signal technique in the same fluidized beds. Also, a simultaneous study of video bubble image, transient force and pressure signals was initiated in a two dimensional fluidized bed. we successfully synchronized three signals so that the relationship of bubble behavior and force pressure signals can be identified and characterized. It has been found that bubble image can well be correlated to the transient force signal of solid particles under certain conditions in three dimensional fluidized beds. Accordingly, it seems that the transient force signals can significantly help understanding the transient motion of bubbles (slugs), which is important to design the fluidized beds.

  4. Applications of Nuclear Track Membranes to Filtration of Medical Injections and Various Transfusions to Remove Solid Particles

    NASA Astrophysics Data System (ADS)

    He, Zhi-Bo; Guo, S.-L.

    Nuclear track membranes produced by China Institute of Atomic Energy (CIAE) in Beijing, China, and the Joint Institute for Nuclear Research (JINR) in Dubna, Russia have been used in the studies of filtration of medical injections and various transfusion liquid medicine to remove solid particles from the medicine. It shows that the filtration devices made of nuclear track membranes are superior to that made of any other types of membranes. Experiments have demonstrated that the removal efficiencies for solid particles with diameters 5 μm can reach over 95% and the flow rate is high enough for use in medical injection and transfusion. The reproducibility of removal efficiencies and flow rate of the new devices are satisfactory to the use in hospitals. Chinese authority in medicine has approved the new devices for use in Chinese hospitals.

  5. Experimental study on dynamics of coherent structures formed by inertial solid particles in three-dimensional periodic flows

    NASA Astrophysics Data System (ADS)

    Gotoda, Masakazu; Melnikov, Denis E.; Ueno, Ichiro; Shevtsova, Valentina

    2016-07-01

    We present experimental results obtained under normal gravity on the dynamics of solid particles in periodic oscillatory thermocapillary-driven flows in a non-isothermal liquid bridge made of decane. Inertial particles of different densities and in the size range approximately 0.75 - 75 μm are able to form stable coherent structures (particle accumulation structures, or PASs). Two image processing techniques were developed and successfully applied to compute time required for an ensemble of particles to form a structure. It is shown that the formation time grows with the decrease of the Stokes number. The observations indicate the probable irrelevance of the memory term for these experiments. Two types of PAS were observed—single (SL-I) and double-loop (SL-II)—which sometimes co-existed. Only large or very dense particles may form an SL-II type structure. A number of novel features of the system were perceived. In some cases, intermittently stable structures emerged (their dynamics is characterized by alternating time intervals during which a structure exists and is destroyed). Whereas in most experiments we observed a conventional symmetric and centered PAS, there were cases when a long-term stable asymmetric structure appeared. Experiments wherein two different types of PAS-forming particles were used simultaneously revealed the destructive role of collisions between the particles on formation of structures.

  6. Experimental study on dynamics of coherent structures formed by inertial solid particles in three-dimensional periodic flows.

    PubMed

    Gotoda, Masakazu; Melnikov, Denis E; Ueno, Ichiro; Shevtsova, Valentina

    2016-07-01

    We present experimental results obtained under normal gravity on the dynamics of solid particles in periodic oscillatory thermocapillary-driven flows in a non-isothermal liquid bridge made of decane. Inertial particles of different densities and in the size range approximately 0.75-75 μm are able to form stable coherent structures (particle accumulation structures, or PASs). Two image processing techniques were developed and successfully applied to compute time required for an ensemble of particles to form a structure. It is shown that the formation time grows with the decrease of the Stokes number. The observations indicate the probable irrelevance of the memory term for these experiments. Two types of PAS were observed-single (SL-I) and double-loop (SL-II)-which sometimes co-existed. Only large or very dense particles may form an SL-II type structure. A number of novel features of the system were perceived. In some cases, intermittently stable structures emerged (their dynamics is characterized by alternating time intervals during which a structure exists and is destroyed). Whereas in most experiments we observed a conventional symmetric and centered PAS, there were cases when a long-term stable asymmetric structure appeared. Experiments wherein two different types of PAS-forming particles were used simultaneously revealed the destructive role of collisions between the particles on formation of structures. PMID:27475066

  7. Solid-particle erosion of in-situ reinforced Si[sub 3]Ni[sub 4

    SciTech Connect

    Marrero, M.; Routbort, J. ); Whalen, P.; Li, Chien-Wei ); Karasek, K.R. )

    1992-04-01

    Steady-state solid-particle erosion has been investigated on in-situ reinforced Si[sub 3]N[sub 4] and the equivalent'' fine-grained hot-isostatically-pressed Si[sub 3]N[sub 4] whose R-curve behaviors are quite different, having K[sub IC] values in the long-crack-limit of 8.3 and 5.6 MPa m[sup [1/2

  8. The fate of solid particles in the Jovian circumplanetary disk : Implications for the formation of the Galilean satellites

    NASA Astrophysics Data System (ADS)

    Ronnet, Thomas; Mousis, Olivier; Vernazza, Pierre

    2016-10-01

    The Galilean satellites are thought to have formed within an accretion disk surrounding Jupiter at the late stages of its formation. However, the structure of the gaseous disk, as well as the size and origin of the solids that eventually formed the satellites are yet to be constrained.Here we model an evolving gaseous disk around Jupiter and investigate the fate of solid particles of different sizes submitted to aerodynamic drag, turbulent diffusion, and heated by the surrounding gas. The motion of the solid particles is integrated in the (r-z) plane, taking into account dust settling and radial drift. The evolution of their ice-to-rock ratio is tracked when they cross the snowline and start to sublimate. Sublimation is coupled to the equations of motion as it changes the radius of the particle and consequently acts on the drag force. The I/R ratio then serves as a comparison to the observed bulk compositions of Io and Europa.

  9. Cinematographic investigations of the explosively driven dispersion and ignition of solid particles

    NASA Astrophysics Data System (ADS)

    Grégoire, Y.; Sturtzer, M.-O.; Khasainov, B. A.; Veyssière, B.

    2014-07-01

    We present results of an experimental study of blast wave propagation and particle dispersion induced by a free-field detonation of spherical charges made of a 125 g C-4 explosive surrounded by inert or reactive particles. Visualization of the flow was performed with a high-frame-rate video camera. Background oriented Schlieren (BOS) methods were adapted to process the images that allowed the detection of the shock waves. BOS analysis also revealed that particles form agglomerates, which may generate precursor perturbations on the recorded pressure signals. While inert glass particles notably delay the shock, the combustion of aluminium particles can accelerate it, especially if they are small atomized or flaked particles. When a mixture of inert glass particles with reactive particles is dispersed, the agglomerates are formed by coalescence of both materials.

  10. Velocity lag of solid particles in oscillating gases and in gases passing through normal shock waves

    NASA Technical Reports Server (NTRS)

    Maxwell, B. R.; Seasholtz, R. G.

    1974-01-01

    The velocity lag of micrometer size spherical particles is theoretically determined for gas particle mixtures passing through a stationary normal shock wave and also for particles embedded in an oscillating gas flow. The particle sizes and densities chosen are those considered important for laser Doppler velocimeter applications. The governing equations for each flow system are formulated. The deviation from Stokes flow caused by inertial, compressibility, and rarefaction effects is accounted for in both flow systems by use of an empirical drag coefficient. Graphical results are presented which characterize particle tracking as a function of system parameters.

  11. Al-MoSi2 Composite Materials: Analysis of Microstructure, Sliding Wear, Solid Particle Erosion, and Aqueous Corrosion

    NASA Astrophysics Data System (ADS)

    Gousia, V.; Tsioukis, A.; Lekatou, A.; Karantzalis, A. E.

    2016-08-01

    In this effort, AMCs reinforced with new intermetallic phases, were produced through casting and compared as far as their microstructure, sliding wear, solid particle erosion, and aqueous corrosion response. Casting was selected as a production method based on the concept: (a) ease-to-handle and low cost production route and (b) optimum homogeneity of the reinforcing phase distribution. The MoSi2 phase was produced through vacuum arc melting and the resulting drops were milled for 30 h to produce fine powder, the characteristics of which were ascertained through SEM-EDS and XRD analysis. MoSi2 was used as precursor source for the final reinforcing phase. The powder material was incorporated in molten Al1050 alloy to additions of 2, 5 and 10 vol.% respectively. Extensive reactivity between the molten Al and the MoSi2 particles was observed, leading to the formation of new reinforcing phases mainly of the Al-Mo system. In all cases, a uniform particle distribution was observed, mainly characterized by isolated intermetallic phases and few intermetallic phase clusters. Sliding wear showed a beneficial action of the reinforcing phase on the wear of the composites. Surface oxidation, plastic deformation, crack formation, and debris abrasive action were the main degradation features. The results of solid particle erosion showed that the mechanism is different as the impact angle and the vol.% change. Regarding the corrosion, the analysis revealed localized corrosion effects. The composite behavior was not altered significantly compared to that of the monolithic matrix.

  12. Formation of Small Blocky Al3Ti Particles via Direct Reaction Between Solid Ti Powders and Liquid Al

    NASA Astrophysics Data System (ADS)

    Liu, Z. W.; Han, Q.; Li, J. G.

    2012-12-01

    The evolution of titanium powders in the pure aluminum melt at a lower temperature was studied in our research. The process involved some titanium powders being added into the pure aluminum melt at 1003 K (730 °C), and then the melt was cast into an ingot after 5 minutes. A reaction layer composed of some loose Al3Ti particles was formed on the solid Ti surface due to the reactive diffusion between titanium and aluminum. In-situ blocky Al3Ti particles smaller than 5 μm were produced in the aluminum matrix. A reaction-peeling model was suggested to illustrate the formation mechanism of Al3Ti particles, and a simple approach for fabricating in-situ Al3Ti/Al-alloy composites was proposed as well.

  13. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques.

    PubMed

    Zhu, Yumin; Zhang, Hua; Shao, Liming; He, Pinjing

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of <2mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles. Zn-Cu, Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.

  14. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques.

    PubMed

    Zhu, Yumin; Zhang, Hua; Shao, Liming; He, Pinjing

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW). In this study, we investigated fine particles of <2mm, which are small fractions in MSW but constitute a significant component of the total heavy metal content, using bulk detection techniques. A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction. We also discussed the association, speciation and source apportionment of heavy metals. Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles. Zn-Cu, Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution. The overlapped enrichment, spatial association, and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles. The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products. PMID:25597689

  15. Study of Particle Rotation Effect in Gas-Solid Flows using Direct Numerical Simulation with a Lattice Boltzmann Method

    SciTech Connect

    Kwon, Kyung; Fan, Liang-Shih; Zhou, Qiang; Yang, Hui

    2014-09-30

    fluid is accelerated from rest by a constant average pressure gradient toward a steady Stokes flow. The simulation results agree well with the theories for the short- and long-time behavior of the drag force. Flows through non-rotational and rotational spheres in simple cubic arrays and random arrays are simulated over the entire range of packing fractions, and both low and moderate particle Reynolds numbers to compare the simulated results with the literature results and develop a new drag force formula, a new lift force formula, and a new torque formula. Random arrays of solid particles in fluids are generated with Monte Carlo procedure and Zinchenko's method to avoid crystallization of solid particles over high solid volume fractions. A new drag force formula was developed with extensive simulated results to be closely applicable to real processes over the entire range of packing fractions and both low and moderate particle Reynolds numbers. The simulation results indicate that the drag force is barely affected by rotational Reynolds numbers. Drag force is basically unchanged as the angle of the rotating axis varies.

  16. Seeking fluid possibility and solid ground: space and movement in mental health service users' experiences of 'crisis'.

    PubMed

    McGrath, Laura; Reavey, Paula

    2015-03-01

    Since the closure of the UK asylums, 'the community' has become short hand for describing a variety of disparate and complex spaces, in which service users manage their experiences of distress. An examination of such spaces here forms the basis of an analysis of the way in which service users move through and within space, to establish agency and dis/order while distressed. Seventeen participants, with various experiences of mental distress took part in a qualitative study, and a further textual analysis was conducted on eight published autobiographies. In the context of the interviews, participants presented drawings of the spaces they occupy during times of crisis, wellbeing and recovery. All texts were analysed using a thematic approach, informed by theories of embodiment and relational space. In this paper, the focus is directed towards two key patterns of movement, in order to explore ways in which participants experiencing various forms of mental health crisis used space in order to maintain and manage feelings of agency. Firstly, incidents where participants described moving towards fluid, outside spaces are explored, with agency being established through seeking, and utilising, greater possibilities for action and engaging others. In addition, the opposite pattern of movement is also explored, using incidents where participants described moving indoors, using the private space of the home to establish order and restore feelings of agency and strength, in contrast to overwhelming experiences in public space. Connections between these patterns of movement and particular forms of distress are discussed. It is argued that community and private spaces are integral to the ways in which selfhood, agency and action is experienced in mental distress, which in turn has implications for policy, treatment and community action.

  17. Method and apparatus for measuring surface movement of a solid object that is subjected to external vibrations

    DOEpatents

    Schultz, Thomas J.; Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

    1995-01-01

    A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

  18. Method and apparatus for measuring surface movement of a solid object that is subjected to external vibrations

    DOEpatents

    Schultz, T.J.; Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

    1995-04-25

    A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figs.

  19. Influence of particle size on pyrolysis and gasification performance of municipal solid waste in a fixed bed reactor.

    PubMed

    Luo, Siyi; Xiao, Bo; Hu, Zhiquan; Liu, Shiming; Guan, Yanwen; Cai, Lei

    2010-08-01

    Pyrolysis and gasification of municipal solid waste (MSW) were carried out in a lab-scale fixed bed reactor in order to evaluate the effects of particle size at different bed temperatures on product yield and composition. The bed temperature was varied from 600 to 900 degrees C and the MSW was separated into three different size fractions (below 5 mm, 50-10 mm and above 10 mm). Particle size and temperature had integrated effects on product yield and composition: higher temperature resulted in higher gas yield with less tar and char, and, at the same temperature, dry gas yield increased with a decrease in particle size, and char and tar yield decreased. The differences due to particle sizes in pyrolysis and gasification performance practically disappeared at the highest temperatures tested. Smaller particle sizes resulted in higher H(2) and CO contents for both pyrolysis and gasification of MSW. Minimizing the size of raw materials is an alternative method to improve the gas quality of MSW pyrolysis and gasification. PMID:20363619

  20. Emission of ultrafine particles from the incineration of municipal solid waste: A review

    NASA Astrophysics Data System (ADS)

    Jones, Alan M.; Harrison, Roy M.

    2016-09-01

    Ultrafine particles (diameter <100 nm) are of great topical interest because of concerns over possible enhanced toxicity relative to larger particles of the same composition. While combustion processes, and especially road traffic exhaust are a known major source of ultrafine particle emissions, relatively little is known of the magnitude of emissions from non-traffic sources. One such source is the incineration of municipal waste, and this article reviews studies carried out on the emissions from modern municipal waste incinerators. The effects of engineering controls upon particle emissions are considered, as well as the very limited information on the effects of changing waste composition. The results of measurements of incinerator flue gas, and of atmospheric sampling at ground level in the vicinity of incinerators, show that typical ultrafine particle concentrations in flue gas are broadly similar to those in urban air and that consequently, after the dispersion process dilutes incinerator exhaust with ambient air, ultrafine particle concentrations are typically indistinguishable from those that would occur in the absence of the incinerator. In some cases the ultrafine particle concentration in the flue gas may be below that in the local ambient air. This appears to be a consequence of the removal of semi-volatile vapours in the secondary combustion zone and abatement plant, and the high efficiency of fabric filters for ultrafine particle collection.

  1. Investigation of Polar Stratospheric Cloud Solid Particle Formation Mechanisms Using ILAS and AVHRR Observations in the Arctic

    NASA Technical Reports Server (NTRS)

    Irie, H.; Pagan, K. L.; Tabazadeh, A.; Legg, M. J.; Sugita, T.

    2004-01-01

    Satellite observations of denitrification and ice clouds in the Arctic lower stratosphere in February 1997 are used with Lagrangian microphysical box model calculations to evaluate nucleation mechanisms of solid polar stratospheric cloud (PSC) particles. The occurrences of ice clouds are not correlated in time and space with the locations of back trajectories of denitrified air masses, indicating that ice particle surfaces are not always a prerequisite for the formation of solid PSCs that lead to denitrification. In contrast, the model calculations incorporating a pseudoheterogeneous freezing process occurring at the vapor-liquid interface can quantitatively explain most of the observed denitrification when the nucleation activation free energy for nitric acid dihydrate formation is raised by only approx.10% relative to the current published values. Once nucleated, the conversion of nitric acid dihydrate to the stable trihydrate phase brings the computed levels of denitrification closer to the measurements. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0320 Atmospheric Composition and SblctureC: loud physics and chemistry; 0340 Atmospheric Composition and Structure: Middle atmosphere-composition and chemistry

  2. Fresnel reflectance in refractive index estimation of light scattering solid particles in immersion liquid

    NASA Astrophysics Data System (ADS)

    Räty, J.; Niskanen, I.; Peiponen, K.-E.

    2010-06-01

    The refractive index of homogenous particle population can be determined by the so-called immersion liquid method. The idea is to find a known liquid whose refractive index matches the index of the particles. We report on a method that simultaneously obtains the refractive index of particles and that of the immersion liquid. It is based on a system using internal light reflection and Fresnel's theory. The method includes a series of straightforward reflection measurements and a fitting procedure. The validity of the method was tested with CaF2 particles. The method has applications within scientific studies of microparticles and nanoparticles or micro-organism in suspensions. It can be also be utilized in industry for the detection of the refractive index of products involving particles for the purpose of improvement of product quality.

  3. Low speed centrifugal casting of Functionally Graded solid cast ingot by anomalous particle distribution

    NASA Astrophysics Data System (ADS)

    Mer, K. K. S.; Ray, S.

    2011-12-01

    Functionally graded cylindrical ingot of Al-Al2O3 composite synthesized by centrifugal casting shows particle distribution and hardness decreasing radially from the outer radius to inner radius. The progressive decrease in alumina content and hardness from the outer radius towards the center may be attributed to higher centrifugal force acting on relatively denser alumina particles during rotation, as compared to that acting on lighter alloy melt. It is also observed, as one moves down from the top to the bottom of cast ingot the alumina content decreases. This is surprising in view of higher density of alumina particles relative to the melt. The particle settling should have resulted at more particles towards the bottom, but distribution observed is in contradiction.

  4. The Interaction Between an Insoluble Particle and an Advancing Solid/Liquid Interface: Micro-Gravity Experiments and Theoretical Developments

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Ssen, Subhayu; Stefanescu, Doru M.

    2003-01-01

    The interaction of an insoluble particle with an advancing solid/liquid interface (SLI) has been a subject of investigation for the past four decades. While the original interest stemmed from geology applications (e.g., frost heaving in soil), researchers soon realized that the complex science associated with such an interaction is relevant to many other scientific fields encompassing metal matrix composites (MMCs), high temperature superconductors, inclusion management in steel, growth of monotectics, and preservation of biological cells. During solidification of a liquid containing an insoluble particle, three distinct interaction phenomena have been experimentally observed: instantaneous engulfment of the particle, continuous pushing, and particle pushing followed by engulfment. It was also observed that for given experimental conditions and particle size there is a critical solidification velocity, V(sub cr), above which a particle is engulfed. During solidification of MMCs pushing leads to particle agglomeration at the grain boundaries and this has detrimental effects on mechanical properties of the casting. Consequently, the process must be designed for instantaneous engulfment to occur. This implies the development of accurate theoretical models to predict V(sub cr), and perform benchmark experiments to test the validity of such models. Although considerable progress has been made in understanding the pushing/engulfment phenomenon (PEP), its quantification in terms of the material and processing parameters remains a focus of research. Since natural convection currents occurring during terrestrial solidification experiments complicate the study of PEP, execution of experiments on the International Space Station (ISS) has been approved and funded by NASA. Extensive terrestrial (1g) experiments and preliminary micro-gravity (mu g) experiments on two space shuttle missions have been conducted in preparation for future experiments on the ISS. The investigated

  5. Foams stabilized with solid particles carrying stimuli-responsive polymer hairs.

    PubMed

    Nakayama, S; Hamasaki, S; Ueno, K; Mochizuki, M; Yusa, S; Nakamura, Y; Fujii, S

    2016-05-25

    Submicrometer-sized polystyrene (PS) particles carrying stimuli-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) hairs with degrees of polymerization of 30, 60 and 90 were synthesized by dispersion polymerization and used as a particulate foam stabilizer. The effects of the composition of these PDEA-PS particles and foam formation conditions on foamability, foam stability and foam microstructures were extensively investigated. The hairy particles were found to work as an effective stabilizer of aqueous foams in basic media, in which the PDEA hairs are not protonated and thus the particle surfaces exhibit suitable wettability at the air-water interface. In contrast, little to no foam or unstable foams were formed in acidic aqueous media, in which the hairs are protonated and are therefore water soluble. Particles carrying longer hairs resulted in greater foamability and more highly stabilized foams that were capable of persisting for more than one month. Foams were found to form in a narrower pH range when using PS particles with longer hairs, due to both entropic and image charge effects. Data obtained from the touch mixer mixing method showed that both foamability and foam stability increased with increases in the concentration of polymer particles up to 10 wt%, because higher concentrations allowed greater air-water interfacial areas to be stabilized. Conversely, only minimal foam was obtained at and above 15 wt% because of the high viscosity of the resulting aqueous particle dispersion. Trials using the homogenizer mixing method showed that foam with a cream-like texture could be formed even at 40 wt% particle concentration as a result of the improved mixing efficiency. Defoamation could be induced by exposing the foams to HCl vapor. Exposure to acidic vapor led to in situ protonation of the 2-(diethylamino)ethyl methacrylate residues, rendering the PDEA hairs hydrophilic and water soluble, and desorption of the PDEA-PS particles from the air

  6. Modulation on coherent vortex structures by dispersed solid particles in a three-dimensional mixing layer.

    PubMed

    Fan, Jianren; Luo, Kun; Zheng, Youqu; Jin, Hanhui; Cen, Kefa

    2003-09-01

    Large-scale vortex structures and their effects on the dispersion of particles in turbulent free shear flows are very important in many industrial applications, such as combustion, pollution control, and materials processing. In order to understand large-scale vortex structures and particle dispersion in depth, as well as their interaction effects, a two-way-coupled three-dimensional mixing layer laden with particles at a Stokes number of 5 initially located in the upper half region is studied numerically. A pseudospectral method was used to directly simulate the flow fluid, and the Lagrangian approach was used to trace particles. The concept of computational particles is introduced to vary the mass loading of particles. The momentum coupling effect introduced by a particle approximates to a point force. The simulation results show that coherent structures are still dominant in the mixing layer, but the flow dynamics and particle dispersion are modulated. The length of large-scale vortex structures is shortened and the pairing is delayed. Higher mass loading results in lower energy of the fluid in the phase of Kelvin-Helmholtz rolling up, while in the pairing process of large-scale vortex structures, the energy of the fluid increases as the mass loading increases. Higher mass loading also leads to larger mixed fluid thickness and Reynolds stresses of the flow. In addition, the particle dispersion along the transverse direction differs from that along the spanwise direction, which indicates that the effects of the addition of a particle on the spanwise large-scale vortex structures are different from those on the streamwise large-scale vortex structures.

  7. Propagation of a cylindrical shock wave in a mixture of a non-ideal gas and small solid particles under the action of monochromatic radiation

    NASA Astrophysics Data System (ADS)

    Sahu, Praveen Kumar; Nath, Gorakh

    2016-07-01

    Cylindrical shock wave in a dusty gas is discussed under the action of monochromatic radiation into stellar atmosphere with a constant intensity on unit area. The gas is assumed to be grey and opaque and shock to be transparent. The dusty gas is assumed to be a mixture of non-ideal gas and small solid particles. To obtain some essential features of the shock propagation, small solid particles are taken as pseudo-fluid and it is assumed that the equilibrium flow condition is maintained in the flow-field. The effects of variation of the parameters of the non-idealness of the gas, the mass concentration of solid particles in the mixture, the ratio of the density of solid particles to the initial density of the gas and the radiation parameter are investigated. It is shown that an increase in the parameters of the non-idealness of the gas and the radiation parameter have decaying effect on the shock waves; whereas with an increase in the ratio of the density of solid particles to the initial density of the gas the shock strength increases. It is found that an increase in the parameter non-idealness of the gas and the ratio of the density of solid particles to the initial density of the gas have opposite behaviour on fluid velocity, pressure and shock strength. Also, it is shown that an increase in the radiation parameter has effect to decrease the flow variables and the shock strength.

  8. Performance of N95 respirators: reaerosolization of bacteria and solid particles.

    PubMed

    Qian, Y; Willeke, K; Grinshpun, S A; Donnelly, J

    1997-12-01

    If a respirator does not contain an exhalation value, and the respirator wearer sneezes or coughs, one may expect previously collected particles to be reaerosolized. This may be of special concern in environments contaminated with airborne microorganisms. The percentages of reaerosolization were measured in a test setup where the number of reaerosolized particles were registered by dynamic aerosol size spectrometry relative to the number of previously collected particles or bacteria. Experiments at low relative humidity have shown that the reaerosolization of particles below 1 micron, including Mycobacterium tuberculosis surrogate bacteria, does not exceed 0.025%, even if the re-entrainment air velocity is as high as 300 cm/sec (i.e., 37 times the air velocity through the respirator during breathing under heavy workload conditions). The reaerosolization of larger particles into dry air was significant at the highest re-entrainment velocity of 300 cm/sec, which simulates violent sneezing or coughing: 0.1% for 3 microns and about 6% for 5-micron test particles. No reaerosolization was detected at relative humidity levels exceeding 35% at these conditions. Thus, it is concluded that the reaerosolization of particles and bacteria, collected on the fibrous filters of N95 respirators, is insignificant at conditions encountered in respirator wear. PMID:9425648

  9. Low-temperature treatment of transformation-toughened partially stabilized magnesia-doped zirconia; A solid particle erosion study

    SciTech Connect

    Srinivasan, S.; Scattergood, R.O. . Dept. of Materials Engineering); Pfeiffer, G.; Sparks, R.G.; Paesler, M.A. . Dept. of Physics)

    1990-05-01

    It is now well established that the mechanical behavior of transformation-toughened partially stabilized zirconias (PSZs) is controlled by R-curve effects arising from the martensitic transformations. Recent studies have induced the martensitic transformation via a liquid-nitrogen-cooling treatment. The result has been the transformation of the tetragonal phase to an orthorhombic phase. The effect of this treatment on solid particle erosion properties is investigated for a set of commercial partially stabilized magnesia-doped zirconia (Mg-PSZ) samples.

  10. The Impact of Variables on Particle Size of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers; A Comparative Literature Review.

    PubMed

    Azhar Shekoufeh Bahari, Leila; Hamishehkar, Hamed

    2016-06-01

    During the past decade, pharmaceutical science has seen rapid growth in interest for nanoscale materials. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are popular research topics recently introduced as nano-scale drug carriers; they have shown numerous merits in drug delivery. Size is the most important index in a nanocarrier affecting its drug delivery efficiency. The influence of preparation conditions and type of lipidic components on the size of SLN and NLC in comparable states seems to be interesting for researchers who investigate these types of carriers. This review highlights the results of SLN and NLC particle size and size distribution comparisons. PMID:27478775

  11. CONDENSED MATTER: STRUCTURE, THERMAL AND MECHANICAL PROPERTIES: Nanoporous AlN particle production from a solid-state metathesis reaction

    NASA Astrophysics Data System (ADS)

    Yan, Guo-Jun; Chen, Guang-De; Wu, Ye-Long

    2009-07-01

    This paper reports that nanoporous AlN particles are synthesized from solid-state metathesis reactions using AlCl3 and Mg3N2 as reactants. The samples are characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction, high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) absorption spectroscopy and Raman spectroscopy. The results show that samples with walls 10 nm in thickness and pores between 10 nm and 100 nm in diameter were produced successfully from these reactions, and their band gap and vibration modes agree with those of AlN bulk crystal.

  12. The Impact of Variables on Particle Size of Solid Lipid Nanoparticles and Nanostructured Lipid Carriers; A Comparative Literature Review

    PubMed Central

    Azhar Shekoufeh Bahari, Leila; Hamishehkar, Hamed

    2016-01-01

    During the past decade, pharmaceutical science has seen rapid growth in interest for nanoscale materials. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are popular research topics recently introduced as nano-scale drug carriers; they have shown numerous merits in drug delivery. Size is the most important index in a nanocarrier affecting its drug delivery efficiency. The influence of preparation conditions and type of lipidic components on the size of SLN and NLC in comparable states seems to be interesting for researchers who investigate these types of carriers. This review highlights the results of SLN and NLC particle size and size distribution comparisons. PMID:27478775

  13. A Preliminary Investigation on the Destruction of Solid-Propellant Rocket Motors by Impact from Small Particles

    NASA Technical Reports Server (NTRS)

    Carter, David J., Jr.

    1960-01-01

    An investigation was conducted to determine whether solid-propellant rocket motors could be ignited and destroyed by small-particle impacts at particle velocities up to a approximately 10,940 feet per second. Spheres ranging from 1/16 to 7/32 inch in diameter were fired into simulated rocket motors containing T-22 propellant over a range of ambient pressures from sea level to 0.12 inch of mercury absolute. Simulated cases of stainless steel, aluminum alloy, and laminated Fiberglas varied in thickness from 1/50 to 1/8 inch. Within the scope of this investigation, it was found that ignition and explosive destruction of simulated steel-case rocket motors could result from impacts by steel spheres at the lowest attainable pressure.

  14. Effect of Particle Size on the Mechanical Properties of Semi-Solid, Powder-Rolled AA7050 Strips

    NASA Astrophysics Data System (ADS)

    Luo, Xia; Liu, Yunzhong

    2016-07-01

    The AA7050 alloy strips can be successfully prepared by semi-solid powder rolling. The effect and factors of particle size on the microstructure, relative density, and mechanical properties were discussed. The results show that coarse starting powders require less liquid to achieve high relative density, and the formed strips have lower elongation compared with that prepared with the fine starting powders. The strength is more related to defects, whereas elongation partially depends on the grain size. Additionally, the fracture mechanism of strips prepared with fine powders is the ductile fracture because many dimples are observed. For relative density, when the initial liquid fraction is lower than 10%, the difference of deformation degree is the main factor. When the liquid fraction is higher than 10-20%, premature solidification and more particle interfaces are the two main factors.

  15. Solid-particle erosion of in-situ reinforced Si{sub 3}Ni{sub 4}

    SciTech Connect

    Marrero, M.; Routbort, J.; Whalen, P.; Li, Chien-Wei; Karasek, K.R.

    1992-04-01

    Steady-state solid-particle erosion has been investigated on in-situ reinforced Si{sub 3}N{sub 4} and the ``equivalent`` fine-grained hot-isostatically-pressed Si{sub 3}N{sub 4} whose R-curve behaviors are quite different, having K{sub IC} values in the long-crack-limit of 8.3 and 5.6 MPa m{sup {1/2}}, respectively. Experiments were carried out at 20{degrees}C, using SiC abrasives, whose diameters ranged from 42 to 1035 {mu}m, varying the angle of impact from 15 to 90{degrees} and the velocity from 50 to 100 to 150 m/s. The erosion rates of the two materials were, within a factor of two, the same, indicating that the long-crack-length-limit toughness is not an indication of erosion resistance, for the range of particle sizes and velocities studied.

  16. Macroscopic yielding in jammed solids is accompanied by a nonequilibrium first-order transition in particle trajectories.

    PubMed

    Kawasaki, Takeshi; Berthier, Ludovic

    2016-08-01

    We use computer simulations to analyze the yielding transition during large-amplitude oscillatory shear of a simple model for soft jammed solids. Simultaneous analysis of global mechanical response and particle-scale motion demonstrates that macroscopic yielding, revealed by a smooth crossover in mechanical properties, is accompanied by a sudden change in the particle dynamics, which evolves from nondiffusive motion to irreversible diffusion as the amplitude of the shear is increased. We provide numerical evidence that this sharp change corresponds to a nonequilibrium first-order dynamic phase transition, thus establishing the existence of a well-defined microscopic dynamic signature of the yielding transition in amorphous materials in oscillatory shear. PMID:27627368

  17. Thermodynamics of water-cubic ice and other liquid-solid coexistence in nanometer-size particles

    NASA Astrophysics Data System (ADS)

    Johari, G. P.

    1998-07-01

    When contributions from the interfacial energy become significant and comparable to the bulk energy, liquid and crystalline phases can coexist at a temperature much lower than the usual melting point. A formalism for this coexistence is given, and thermodynamic conditions for the melting of nanometer-size cubic ice crystals are derived when both the ice and water are at an equilibrium vapor pressure. By using the approximate values of surface energy and the enthalpy and entropy of melting, it is shown that nanometer-size water droplets can coexist with cubic ice particles of about the same size at temperatures in the 150-180 K range. The unusually large decrease in the temperature of a liquid-solid phase equilibrium is expected to be a general phenomenon in the nanometer-size films, clusters, and particles of materials.

  18. Evaporation of suspensions to form an incompressible cake and to fill filter pores with solid particles

    NASA Astrophysics Data System (ADS)

    Khuzhayorov, B. Kh.

    2011-11-01

    Equations of filtration of suspensions to form an incompressible cake of particles on the surface of the filter with simultaneous passage of a certain share of the particles from the cake to the filter's pore space and next to the region of a filtered liquid are derived from the principles of the mechanics of multiphase media. The influence of the travel of the particles in the region of the cake and the filter on the dynamics of growth of the cake bed is investigated. An analysis of the derived dynamic filtration equations shows that allowance for the factors of travel and accumulation of particles in the cake and the filter causes their total filtration resistance, in particular the resistance in the inertial component of the filtration law, to decrease.

  19. Numerical investigation of the influence of crystallization of ultrafine particles of aluminum oxide on energy characteristics of solid-propellant rocket engine

    NASA Astrophysics Data System (ADS)

    Dyachenko, N. N.; Dyachenko, L. I.

    2014-08-01

    The results of numerical investigation of a multiphase flow considering coagulation, crushing and crystallization of the particles of polydispersed condensate in the nozzles of solid-propellant rocket engine are presented. The influence of particles crystallization on the energy characteristics of the engine is shown.

  20. Compact and multi-view solid state neutral particle analyzer arrays on National Spherical Torus Experiment-Upgrade

    NASA Astrophysics Data System (ADS)

    Liu, D.; Heidbrink, W. W.; Tritz, K.; Fredrickson, E. D.; Hao, G. Z.; Zhu, Y. B.

    2016-11-01

    A compact and multi-view solid state neutral particle analyzer (SSNPA) diagnostic based on silicon photodiode arrays has been successfully tested on the National Spherical Torus Experiment-Upgrade. The SSNPA diagnostic provides spatially, temporally, and pitch-angle resolved measurements of fast-ion distribution by detecting fast neutral flux resulting from the charge exchange (CX) reactions. The system consists of three 16-channel subsystems: t-SSNPA viewing the plasma mid-radius and neutral beam (NB) line #2 tangentially, r-SSNPA viewing the plasma core and NB line #1 radially, and p-SSNPA with no intersection with any NB lines. Due to the setup geometry, the active CX signals of t-SSNPA and r-SSNPA are mainly sensitive to passing and trapped particles, respectively. In addition, both t-SSNPA and r-SSNPA utilize three vertically stacked arrays with different filter thicknesses to obtain coarse energy information. The experimental data show that all channels are operational. The signal to noise ratio is typically larger than 10, and the main noise is x-ray induced signal. The active and passive CX signals are clearly observed on t-SSNPA and r-SSNPA during NB modulation. The SSNPA data also indicate significant losses of passing particles during sawteeth, while trapped particles are weakly affected. Fluctuations up to 120 kHz have been observed on SSNPA, and they are strongly correlated with magnetohydrodynamics instabilities.

  1. On the metastability of the hexatic phase during the melting of two-dimensional charged particle solids

    SciTech Connect

    Derzsi, Aranka; Kovács, Anikó Zs.; Donkó, Zoltán; Hartmann, Peter

    2014-02-15

    For two-dimensional many-particle systems, first-order, second-order, single step continuous, as well as two-step continuous (KTHNY-like) melting transitions have been found in previous studies. Recent computer simulations, using particle numbers in the ≥10{sup 5} range, as well as a few experimental studies, tend to support the two-step scenario, where the solid and liquid phases are separated by a third, so called hexatic phase. We have performed molecular dynamics simulations on Yukawa (Debye-Hückel) systems at conditions earlier predicted to belong to the hexatic phase. Our simulation studies on the time needed for the equilibration of the systems conclude that the hexatic phase is metastable and disappears in the limit of long times. We also show that simply increasing the particle number in particle simulations does not necessarily result in more accurate conclusions regarding the existence of the hexatic phase. The increase of the system size has to be accompanied with the increase of the simulation time to ensure properly thermalized conditions.

  2. Supercritical fluid precipitation of ketoprofen in novel structured lipid carriers for enhanced mucosal delivery--a comparison with solid lipid particles.

    PubMed

    Gonçalves, V S S; Matias, A A; Rodríguez-Rojo, S; Nogueira, I D; Duarte, C M M

    2015-11-10

    Structured lipid carriers based on mixture of solid lipids with liquid lipids are the second generation of solid lipid particles, offering the advantage of improved drug loading capacity and higher storage stability. In this study, structured lipid carriers were successfully prepared for the first time by precipitation from gas saturated solutions. Glyceryl monooleate (GMO), a liquid glycerolipid, was selected in this work to be incorporated into three solid glycerolipids with hydrophilic-lipophilic balance (HLB) ranging from 1 to 13, namely Gelucire 43/01™, Geleol™ and Gelucire 50/13™. In general, microparticles with a irregular porous morphology and a wide particle size distribution were obtained. The HLB of the individual glycerolipids might be a relevant parameter to take into account during the processing of solid:liquid lipid blends. As expected, the addition of a liquid lipid into a solid lipid matrix led to increased stability of the lipid carriers, with no significant modifications in their melting enthalpy after 6 months of storage. Additionally, Gelucire 43/01™:GMO particles were produced with different mass ratios and loaded with ketoprofen. The drug loading capacity of the structured lipid carriers increased as the GMO content in the particles increased, achieving a maximum encapsulation efficiency of 97% for the 3:1 mass ratio. Moreover, structured lipid carriers presented an immediate release of ketoprofen from its matrix with higher permeation through a mucous-membrane model, while solid lipid particles present a controlled release of the drug with less permeation capacity.

  3. Experimental investigation of bubbling in particle beds with high solid holdup

    SciTech Connect

    Cheng, Songbai; Hirahara, Daisuke; Tanaka, Youhei; Gondai, Yoji; Zhang, Bin; Matsumoto, Tatsuya; Morita, Koji; Fukuda, Kenji; Yamano, Hidemasa; Suzuki, Tohru; Tobita, Yoshiharu

    2011-02-15

    A series of experiments on bubbling behavior in particle beds was performed to clarify three-phase flow dynamics in debris beds formed after core-disruptive accident (CDA) in sodium-cooled fast breeder reactors (FBRs). Although in the past, several experiments have been performed in packed beds to investigate flow patterns, most of these were under comparatively higher gas flow rate, which may be not expected during an early sodium boiling period in debris beds. The current experiments were conducted under two dimensional (2D) and three dimensional (3D) conditions separately, in which water was used as liquid phase, and bubbles were generated by injecting nitrogen gas from the bottom of the viewing tank. Various particle-bed parameters were varied, including particle-bed height (from 30 mm to 200 mm), particle diameter (from 0.4 mm to 6 mm) and particle type (beads made of acrylic, glass, alumina and zirconia). Under these experimental conditions, three kinds of bubbling behavior were observed for the first time using digital image analysis methods that were further verified by quantitative detailed analysis of bubbling properties including surface bubbling frequency and surface bubble size under both 2D and 3D conditions. This investigation, which hopefully provides fundamental data for a better understanding and an improved estimation of CDAs in FBRs, is expected to benefit future analysis and verification of computer models developed in advanced fast reactor safety analysis codes. (author)

  4. Particle response to shock waves in solids: dynamic witness plate/PIV method for detonations

    NASA Astrophysics Data System (ADS)

    Murphy, Michael J.; Adrian, Ronald J.

    2007-08-01

    Studies using transparent, polymeric witness plates consisting of polydimethlysiloxane (PDMS) have been conducted to measure the output of exploding bridge wire (EBW) detonators and exploding foil initiators (EFI). Polymeric witness plates are utilized to alleviate particle response issues that arise in gaseous flow fields containing shock waves and to allow measurements of shock-induced material velocities to be made using particle image velocimetry (PIV). Quantitative comparisons of velocity profiles across the shock waves in air and in PDMS demonstrate the improved response achieved by the dynamic witness plate method. Schlieren photographs complement the analysis through direct visualization of detonator-induced shock waves in the witness plates.

  5. Inverse gas chromatography a tool to follow physicochemical modifications of pharmaceutical solids: Crystal habit and particles size surface effects.

    PubMed

    Cares-Pacheco, M G; Calvet, R; Vaca-Medina, G; Rouilly, A; Espitalier, F

    2015-10-15

    Powders are complex systems and so pharmaceutical solids are not the exception. Nowadays, pharmaceutical ingredients must comply with well-defined draconian specifications imposing narrow particle size range, control on the mean particle size, crystalline structure, crystal habits aspect and surface properties of powders, among others. The different facets, physical forms, defects and/or impurities of the solid will alter its interaction properties. A powerful way of studying surface properties is based on the adsorption of an organic or water vapor on a powder. Inverse gas chromatography (IGC) appears as a useful method to characterize the surface properties of divided solids. The aim of this work is to study the sensitivity of IGC, in Henry's domain, in order to detect the impact of size and morphology in surface energy of two crystalline forms of an excipient, d-mannitol. Surface energy analyses using IGC have shown that the α form is the most energetically active form. To study size and shape influence on polymorphism, pure α and β mannitol samples were cryomilled (CM) and/or spray dried (SD). All forms showed an increase of the surface energy after treatment, with a higher influence for β samples (γs(d) of 40-62 mJ m(-2)) than for α mannitol samples (γs(d) of 75-86 mJ m(-2)). Surface heterogeneity analysis in Henry's domain showed a more heterogeneous β-CM sample (62-52 mJ m(-2)). Moreover, despite its spherical shape and quite homogeneous size distribution, β-SD mannitol samples showed a slightly heterogeneous surface (57-52 mJ m(-2)) also higher than the recrystallized β pure sample (∼40 mJ m(-2)).

  6. Two-Dimensional Experiment on the Jet Formation during Dispersal of Solid Particles by Shock Wave

    NASA Astrophysics Data System (ADS)

    Rodriguez, V.; Jourdan, G.; Mariani, C.; Saurel, R.; Loraud, J.-C.; Houas, L.; Lapébie, E.; Munier, L.; Osmont, A.

    For several years, investigations have been achieved to determine the physical mechanism which governs particle jet formation induced by the dispersion of a granular medium exposed to an impulsive pressure load, i.e. by a shock or a blast wave. This kind of such physical mechanism is observed during explosions or in nature as volcanic eruptions [1].

  7. Formation of nanowires via single particle-triggered linear polymerization of solid-state aromatic molecules.

    PubMed

    Horio, Akifumi; Sakurai, Tsuneaki; Lakshmi, G B V S; Kumar Avasthi, Devesh; Sugimoto, Masaki; Yamaki, Tetsuya; Seki, Shu

    2016-08-11

    Nanowires occupy a prestigious place in nanoelectronics, nanomechanics, and biomimetics. Although there are notable methods to grow nanowires via self-assembly, there is a key drawback in the need to find out the specific conditions appropriate for each system. In this sense, universal techniques to fabricate such nanowires from various organic materials have been sought for the continued progress of the related research field. Here we report one of the promising and facile methodologies to quantitatively produce nanowires with controlled geometrical parameters. In this method, referred to as "Single Particle-Triggered Linear Polymerization (STLiP)", organic thin films on a supporting substrate were irradiated with high-energy charged particles, accelerated by particle accelerators. Each particle penetrates from the top of the films to the substrate while gradually releasing kinetic energy along its trajectory (ion track), generating reactive intermediates such as radical species that eventually induce propagation reactions. The resulting polymerized products were integrated into nanowires with uniform diameter and length that can be isolated via development with appropriate organic solvents. Considering the widely applicable nature of STLiP to organic materials, the present technique opens a new door for access to a number of functional nanowires and their assembly.

  8. Development of spherical iron(II) sulfate heptahydrate-containing solid particles with sustained drug release.

    PubMed

    Szabó-Révész, Piroska; Farkas, Béla; Gregor, Tamás; Nagy, Kálmán; Pallagi, Edina

    2007-05-01

    The aim of this work was to develop a simple, economic procedure for the manufacturing of coated iron(II) sulfate particles by using a crystallization technique for the development of round particles, followed by coating with a lipophilic material. Several batches of iron(II) sulfate heptahydrate were produced by a cooling crystallization, with variation of the crystallization parameters. The spherical crystals were coated with stearin. The products were characterized for particle size, roundness, bulk density and in vitro drug dissolution. Crystallization was performed from deionized water with no addition of seed crystals and by cooling by applying a linear cooling rate. The developed iron(II) sulfate crystals were round with average diameter of 729+/-165 microm. The best form for the sustained release of iron(II) sulfate was the sample HTP-2 which contained 11% of stearin relative to the iron(II) sulfate. The spherical crystallization of iron(II) sulfate is simple and fast, and does not require a dangerous, expensive solvent. The round particles can coat directly with lipophilic material which results in slow release of iron(II) sulfate and protects the iron(II) from oxidation and inhibits the loss of crystal water. The coated crystals can be filled into capsules to yield the final dosage form.

  9. Formation of nanowires via single particle-triggered linear polymerization of solid-state aromatic molecules.

    PubMed

    Horio, Akifumi; Sakurai, Tsuneaki; Lakshmi, G B V S; Kumar Avasthi, Devesh; Sugimoto, Masaki; Yamaki, Tetsuya; Seki, Shu

    2016-08-11

    Nanowires occupy a prestigious place in nanoelectronics, nanomechanics, and biomimetics. Although there are notable methods to grow nanowires via self-assembly, there is a key drawback in the need to find out the specific conditions appropriate for each system. In this sense, universal techniques to fabricate such nanowires from various organic materials have been sought for the continued progress of the related research field. Here we report one of the promising and facile methodologies to quantitatively produce nanowires with controlled geometrical parameters. In this method, referred to as "Single Particle-Triggered Linear Polymerization (STLiP)", organic thin films on a supporting substrate were irradiated with high-energy charged particles, accelerated by particle accelerators. Each particle penetrates from the top of the films to the substrate while gradually releasing kinetic energy along its trajectory (ion track), generating reactive intermediates such as radical species that eventually induce propagation reactions. The resulting polymerized products were integrated into nanowires with uniform diameter and length that can be isolated via development with appropriate organic solvents. Considering the widely applicable nature of STLiP to organic materials, the present technique opens a new door for access to a number of functional nanowires and their assembly. PMID:27355341

  10. Fundamental study of ammonia-sulfur dioxide reactions to form solid particles. Final report

    SciTech Connect

    Biswas, P.; Bai, H.

    1994-01-18

    The effects of reaction residence time, presence of inert particles and moisture content on the SO{sub 2} removal and the product particle size distributions have been determined. Results indicated that both gas phase and particle phase reach equilibria in a very short time. The presence of inert particles increases the SO{sub 2} removal efficiency slightly, with a greater increase in removal efficiency at higher surface areas. Moisture content is the most important parameter affecting SO{sub 2} removal. Increasing the moisture content from 1.6% to 6.4% by volume results in a 30% increase of the SO{sub 2} removal at a reaction temperature of 51{degree}C. The products at near anhydrous conditions were concluded to be NH{sub 3}SO{sub 2}, (NH{sub 3}){sub 2}SO{sub 2} and (NH{sub 4}){sub 2}S{sub 2}O{sub 5}. While the products at humid conditions could be either the 1:1 sulfites, NH{sub 4}HSO{sub 3} and (NH{sub 4}){sub 2}S{sub 2}O{sub 5}, or the 2:1 sulfites, (NH{sub 4}){sub 2}SO{sub 3} and (NH{sub 4}){sub 2}SO{sub 3} {minus}H{sub 2}O, or a mixture of the 1:1 and 2:1 sulfite. Those sulfite particles could subsequently oxidize to form the more stable sulfate particles. A gas-to-particle formation model has been developed to simulate the NH{sub 3}-SO{sub 2} system in the presence and absence of seed aerosols at trace water conditions. This model accounts for simultaneous nucleation, coagulation, condensation and chemical reaction. The applicability of utilizing ammonia injection to a flue gas system has been discussed in terms of two possible removal schemes. One utilizes ammonia injection alone and the other is in conjunction with the injection of Ca(OH){sub 2} slurry in a spray dryer system. Both schemes have the potential of achieving over 90% SO{sub 2} removal from power plants burning high-sulfur coals.

  11. The Effect of Particle Size on the Deposition of Solid Lipid Nanoparticles in Different Skin Layers: A Histological Study

    PubMed Central

    Mardhiah Adib, Zahra; Ghanbarzadeh, Saeed; Kouhsoltani, Maryam; Yari Khosroshahi, Ahmad; Hamishehkar, Hamed

    2016-01-01

    Purpose: In the present study the effect of particle size, as a substantial parameters in skin penetration, on the deposition depth and rate of SLNs in different layers of skin was explored. Methods: SLNs in different particle size ranges (80, 333 and 971 nm) made of Precirol as solid lipid were prepared using hot melt homogenization technique and pigmented by Rhodamine B to be able to be tracked in the skin under inspection of fluorescent microscopy. After 0.5 h, 3 h, 6 h and 24 h of SLNs administration on rat skin, animals were sacrificed and exercised skins were sliced by a freeze microtome. SLNs were monitored in the skin structure under fluorescence microscope. Results: The size of SLNs played a crucial role in the penetration to deep skin layers. The sub100 nm size range of SLNs showed the most promising skin penetration rate and depth mainly via hair follicles. Conclusion: The results of the present study indicated that the selection of an appropriate size of particles may be a valuable factor impacting the therapeutic outcomes of dermal drug administration. PMID:27123415

  12. High-solids paint overspray aerosols in a spray painting booth: particle size analysis and scrubber efficiency

    SciTech Connect

    Chan, T.L.; D'arcy, J.B.; Schreck, R.M.

    1986-07-01

    Particle size distributions of high-solids acrylic-enamel paint overspray aerosols were determined isokinetically in a typical downdraft spray painting booth in which a 7-stage cascade impactor was used. Three different industrial paint atomizers were used, and the paint aerosols were characterized before and after a paint both scrubber. The mass median aerodynamic diameter (MMAD) of a metallic basecoat and an acrylic clearcoat paint aerosol from air-atomized spray guns ranged from 4-12 ..mu..m and was dependent on atomization pressure. When the paint booth was operated under controlled conditions simulating those in a plant, the collection efficiency of paint overspray aerosols by a paint scrubber was found to be size dependent and decreased sharply for particles smaller than 2 ..mu..m to as low as 64% for clearcoat paint particles of 0.6 ..mu..m. Improvement in the overall particulate removal efficiency can be achieved by optimizing the spray painting operations so as to produce the least amount of fine overspray paint aerosols less than 2 ..mu..m. Maintaining a higher static pressure drop across the paint both scrubber also will improve scrubber performance.

  13. Experimental study on thermophoretic deposition of soot particles in laminar diffusion flames along a solid wall in microgravity

    SciTech Connect

    Choi, Jae-Hyuk; Chung, Suk Ho; Fujita, Osamu; Tsuiki, Takafumi; Kim, Junhong

    2008-09-15

    Soot deposition process in diffusion flames along a solid wall has been investigated experimentally under a microgravity environment. An ethylene (C{sub 2}H{sub 4}) diffusion flame was formed around a cylindrical rod-burner with the surrounding air velocities of V{sub a} = 2.5, 5, and 10 cm/s, the oxygen concentration of 35%, and the burner wall temperature of 300 K. A laser extinction method was adopted to measure the distribution of soot volume fraction. The experiments determined the trace of maximum soot concentration together with the relative distance of the trace of flame. Results showed that the distance was about 2-5 mm. As the surrounding air velocity increased, the region of the soot particle distribution moved closer to the burner wall. The soot particles near the flame zone tended to move away from the flame zone because of the thermophoretic force and to concentrate at a certain narrow region inside the flame. Because of the simultaneous effects of convection and the thermophoresis, soot particles finally adhered to the burner wall. It has been found that there existed an optimal air velocity for the early deposition of soot on the furnace wall. (author)

  14. Cross-correlation focus method with an electrostatic sensor array for local particle velocity measurement in dilute gas-solid two-phase flow

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Zhang, Jingyu; Gao, Wenbin; Ding, Hongbing; Wu, Weiping

    2015-11-01

    The gas-solid two-phase flow has been widely applied in the power, chemical and metallurgical industries. It is of great significance in the research of gas-solid two-phase flow to measure particle velocity at different locations in the pipeline. Thus, an electrostatic sensor array comprising eight arc-shaped electrodes was designed. The relationship between the cross-correlation (CC) velocity and the distribution of particle velocity, charge density and electrode spatial sensitivity was analysed. Then the CC sensitivity and its calculation method were proposed. According to the distribution of CC sensitivity, it was found that, between different electrode pairs, it had different focus areas. The CC focus method was proposed for particle velocity measurement at different locations and validated by a belt-style electrostatic induction experiment facility. Finally, the particle velocities at different locations with different flow conditions were measured to research the particle velocity distribution in a dilute horizontal pneumatic conveying pipeline.

  15. Solid-particle erosion behavior of cast alloys used in the mining industry

    NASA Astrophysics Data System (ADS)

    Atapek, Ş. Hakan; Fidan, Sinan

    2015-12-01

    The erosive-wear response of five commercial ferrous-based cast alloys used for crushing was examined in this study. The microstructures of the alloys were modified to elucidate the effect of microstructural features on wear. Erosion tests were conducted using aluminum oxide particles (90-125 μm) at 70 m/s and a normal impact angle (90°). The worn surfaces were characterized by scanning electron microscopy and 3D non-contact laser profilometry. It is found that (i) a pearlitic structure exhibiting a greater plastic deformation than both bainitic and martensitic structures shows the greatest resistance to erosive wear at normal impact and (ii) the fracture characteristics of carbide and graphite particles plays an important role in determining the erosion wear behavior of the cast alloy matrices.

  16. Effects of solid particle content on properties of o/w Pickering emulsions.

    PubMed

    Frelichowska, Justyna; Bolzinger, Marie-Alexandrine; Chevalier, Yves

    2010-11-15

    The control of droplet size and stability of oil-in-water Pickering emulsions stabilized by hydrophobized fumed silica was investigated. Three regimes were observed according to the silica content: instability at low silica content, stable emulsions with droplet size controlled by the silica content, and emulsions of constant size set by the emulsification process at high silica concentrations. The oil-to-silica ratio was the relevant parameter of the size control in the medium concentration regime. Centrifugation experiments and particle size distribution measurements gave evidence of the presence of excess silica present as dispersion in the aqueous phase in the high silica content regime. Adsorption of silica to the droplet surface did not follow adsorption equilibrium; strong adsorption prevailed. Lastly, aggregation of silica particles appeared a crucial parameter. Oil adsorption and capillary condensation of oil within the silica aggregates provided a supplementary mechanism of silica aggregation that contributed to the stability of emulsions.

  17. The Mean-Field Limit for Solid Particles in a Navier-Stokes Flow

    NASA Astrophysics Data System (ADS)

    Desvillettes, Laurent; Golse, François; Ricci, Valeria

    2008-06-01

    We propose a mathematical derivation of Brinkman's force for a cloud of particles immersed in an incompressible viscous fluid. Specifically, we consider the Stokes or steady Navier-Stokes equations in a bounded domain Ω⊂ℝ3 for the velocity field u of an incompressible fluid with kinematic viscosity ν and density 1. Brinkman's force consists of a source term 6 π ν j where j is the current density of the particles, and of a friction term 6 π ν ρ u where ρ is the number density of particles. These additional terms in the motion equation for the fluid are obtained from the Stokes or steady Navier-Stokes equations set in Ω minus the disjoint union of N balls of radius ɛ=1/ N in the large N limit with no-slip boundary condition. The number density ρ and current density j are obtained from the limiting phase space empirical measure 1/Nsum_{1le kle N}δ_{xk,vk} , where x k is the center of the k-th ball and v k its instantaneous velocity. This can be seen as a generalization of Allaire's result in [Arch. Ration. Mech. Anal. 113:209-259, [1991

  18. Radioluminescence of solid neodymium-doped laser materials excited by {alpha}-particles and fission fragments

    SciTech Connect

    Seregina, E A; Seregin, A A

    2013-02-28

    The characteristics of radioluminescence of Nd{sup 3+} : Y{sub 3}Al{sub 5}O{sub 12} crystals and laser glasses under excitation by plutonium-239 ({sup 239}Pu) {alpha}-particles, as well as by {alpha}-particles and spontaneous fission fragments of californium-252 ({sup 252}Cf), are studied. The radioluminescence branching ratios {beta}{sub ij} for the transition from the {sup 2}F2{sub 5/2} level to the {sup 2S+1}L{sub J} levels in Nd{sup 3+} : Y{sub 3}Al{sub 5}O{sub 12} crystals are measured. Radioluminescence from the {sup 2}P{sub 3/2} level to low-lying levels is observed. The {beta}{sub ij} ratios for transitions from the high-lying {sup 2}F2{sub 5/2}, {sup 4}D{sub 3/2}, and {sup 2}P{sub 3/2} levels are theoretically calculated. The lifetimes of metastable levels of Nd{sup 3+} excited by {sup 252}Cf fission fragments are measured. The efficiency of the conversion of energy of {alpha}-particles and fission fragments to the energy of optical radiation of Nd{sup 3+} : Y{sub 3}Al{sub 5}O{sub 12} crystals and laser glasses is determined. (active media)

  19. Radioluminescence of solid neodymium-doped laser materials excited by α-particles and fission fragments

    NASA Astrophysics Data System (ADS)

    Seregina, E. A.; Seregin, A. A.

    2013-02-01

    The characteristics of radioluminescence of Nd3+ : Y3Al5O12 crystals and laser glasses under excitation by plutonium-239 (239Pu) α-particles, as well as by α-particles and spontaneous fission fragments of californium-252 (252Cf), are studied. The radioluminescence branching ratios βij for the transition from the 2F25/2 level to the 2S+1LJ levels in Nd3+ : Y3Al5O12 crystals are measured. Radioluminescence from the 2P3/2 level to low-lying levels is observed. The βij ratios for transitions from the high-lying 2F25/2, 4D3/2, and 2P3/2 levels are theoretically calculated. The lifetimes of metastable levels of Nd3+ excited by 252Cf fission fragments are measured. The efficiency of the conversion of energy of α-particles and fission fragments to the energy of optical radiation of Nd3+ : Y3Al5O12 crystals and laser glasses is determined.

  20. Collisions of energetic particles with atoms, molecules & solids: A theoretical study

    NASA Astrophysics Data System (ADS)

    Quashie, Edwin Exam

    The detailed knowledge of the accurate ion-solid interaction is at the heart of many technological applications such as nuclear safety, applied material science, medical physics and fusion and fission applications. Its accurate evaluation poses an enormous challenge due to the need of incorporating electronic structure, bound states, size effects, basis sets, and the quantum classical aspects of the problem. Most recent approaches relying on the fitting to experimental data or phenomenological model, fail to describe the ion-solid interaction properly (see [S. N. Markin, D. Primetzhofer, M. Spitz, and P. Bauer, Phys. Rev. B 80 (2009)]) for slow ions. A general Time-Dependent Density Functional Theory (TDDFT) is used in this thesis to evaluate electron-dynamics easily. For the first time a unified theory is proposed to describe the ion-solid interaction accurately over several orders of magnitude in the ion velocities, unveiling different regimes that before were only partially seen by separate experiments and rarely by any level of existing theory. We identified an electronic stopping which in the band-regime produces a quantum friction that is nonlinear with a power-law with an exponent ˜1.5. At low velocity this nonlinear effect will provide a new impetus for experimental investigations and an improve microscopic models of electron-ion dissipative dynamics. Our study will potentially impact both the experimental and theoretical research in condensed matter. We have applied our developed theory to study stopping of H+ in Cu. The target Cu comprises complicated band structure and this system will help to understand radiation of matter, both in its experimental understanding and also in the modeling of the process, for example in the context of damped molecular dynamics for the simulation of radiation cascades. At this present stage in the field of ion-solid interactions and quantum dissipative dynamics, our findings remain very significant. The same techniques are

  1. Possibilities of radioisotope measuring in control of an unstable solid particles hydrotransport

    NASA Astrophysics Data System (ADS)

    Petryka, Leszek; Zych, Marcin; Hanus, Robert; Sobota, Jerzy; Vlasak, Pavel; Śleziak, Monika; Świsulski, Dariusz

    2016-03-01

    The paper presents γ-radiation proposal to control a multiphase flow, independently from circumstances. So this method may be applied even in compound industrial or environmental processes. Moreover in many cases, it is the only method for applications for dense mixture containing coarse angular grains. The constructed equipment allows continuous measurement of density as well as solid phase for both concentration and average velocity. Due to pressure loss, it gives the output digital signal convenient for cybernation of the control process. The proposed procedures were tested at a laboratory installation modeling conditions expected during planned excavation of nodules from Pacific bottom.

  2. Fish Individual-based Numerical Simulator (FINS): A particle-based model of juvenile salmonid movement and dissolved gas exposure history in the Columbia River Basin

    SciTech Connect

    Scheibe, Timothy D.; Richmond, Marshall C.

    2002-01-30

    This paper describes a numerical model of juvenile salmonid migration in the Columbia and Snake Rivers. The model, called the Fish Individual-based Numerical Simulator or FINS, employs a discrete, particle-based approach to simulate the migration and history of exposure to dissolved gases of individual fish. FINS is linked to a two-dimensional (vertically-averaged) hydrodynamic simulator that quantifies local water velocity, temperature, and dissolved gas levels as a function of river flow rates and dam operations. Simulated gas exposure histories can be input to biological mortality models to predict the effects of various river configurations on fish injury and mortality due to dissolved gas supersaturation. Therefore, FINS serves as a critical linkage between hydrodynamic models of the river system and models of biological impacts. FINS was parameterized and validated based on observations of individual fish movements collected using radiotelemetry methods during 1997 and 1998. A quasi-inverse approach was used to decouple fish swimming movements from advection with the local water velocity, allowing inference of time series of non-advective displacements of individual fish from the radiotelemetry data. Statistical analyses of these displacements are presented, and confirm that strong temporal correlation of fish swimming behavior persists in some cases over several hours. A correlated random-walk model was employed to simulate the observed migration behavior, and parameters of the model were estimated that lead to close correspondence between predictions and observations.

  3. Solid phospholipid nano-particles: investigations into formulation and dissolution properties of griseofulvin.

    PubMed

    Brinkmann-Trettenes, Ulla; Bauer-Brandl, Annette

    2014-06-01

    Solid phospholipid (PL) nanoparticles with griseofulvin (GRIS) as a model drug were prepared by co-spray drying. Their dissolution properties were compared with formulations containing the physical blends of the native crystalline drug and excipient materials, and physical blends of the spray dried materials. Co-spray drying was performed from ethanol+water solutions (80+20) using Büchi Nano Spray Dryer B-90. Dissolution profiles in phosphate buffer (PBS), simulated intestinal fluids (fasted state simulated intestinal fluid (FaSSIF)) and pancreatin containing media (PAN) were studied. It was found that the influence of PL on the dissolution profile was affected by both the solid state of the drug formulation and the dissolution medium: the co-SD formulations showed the fastest release in all media. The amount of GRIS dissolved after 5h increases by a factor of 7 for the co SD as compared to physical blend of native materials in PBS, and a factor of 4 in FaSSIF respectively. Surprisingly, in contrast to PBS, dissolution rate in FaSSIF decreased with increasing the PL content. All the pancreatin containing media showed a decrease in dissolution rate and extent independently of the processing methods due to an incompatibility between GRIS and PAN. PMID:24614583

  4. Particle size and density of a slurry from ultrasonic backscattering measurements at a solid interface

    NASA Astrophysics Data System (ADS)

    Greenwood, Margaret Stautberg

    2012-09-01

    The pivotal experiment was performed with a setup in which a plastic cylinder was mounted on the top of a horizontal Rexolite plate and a transducer mounted directly below the cylinder; a single layer of stationary 1588-μm acrylic spheres was placed in the cylinder filled with water. Two well-separated signals were received by the transducer operating in the pulse-echo mode: (1) a signal due to the reflection from water at the interface and (2) a time-delayed signal resulting from the backscattering from the spheres of diameter D. The important observation was that the time delay was equal to 2 D/c using standard notation. A method was developed to use the FFT phase difference between the incident and scattered signals at the interface to determine the time-delay as a function of frequency, the backscattering coefficient M versus frequency, a particle size distribution, and an average value of the diameter. Experimental average diameter results are shown in the square brackets for nominal particle sizes: (1) 1588-μm acrylic spheres [1564 μm], (2) polystyrene spheres for diameters from 200 μm to 500 μm [260 μm-536 μm], (3) suspended slurry of 250-300 μm polystyrene spheres at 2.25 MHz [253 μm], (4) 794 μm [759 μm] and 1588-μm [1623 μm] Teflon spheres, (5) 1588-μm stainless steel spheres [1674 μm], and (6) suspended slurry of 250-300 μm polystyrene spheres [275 μm] at 3.5 MHz for seven volume fractions. Density and particle size measurements were obtained for the latter. For the density measurement, the FFT amplitude of the scattered signal was summed from 2 to 4 MHz for each slurry. A plot of the square root of the FFT-amplitude-sum versus the volume fraction yields a straight line, passing through the origin. A calibration of the experimental setup is obtained by fitting a straight line through the data with error bars. Thus, the volume fraction for a slurry of unknown concentration can be determined by measuring the FFT-amplitude-sum. The density

  5. Particle size and density of a slurry from ultrasonic backscattering measurements at a solid interface.

    PubMed

    Greenwood, Margaret Stautberg

    2012-09-01

    The pivotal experiment was performed with a setup in which a plastic cylinder was mounted on the top of a horizontal Rexolite plate and a transducer mounted directly below the cylinder; a single layer of stationary 1588-μm acrylic spheres was placed in the cylinder filled with water. Two well-separated signals were received by the transducer operating in the pulse-echo mode: (1) a signal due to the reflection from water at the interface and (2) a time-delayed signal resulting from the backscattering from the spheres of diameter D. The important observation was that the time delay was equal to 2 D/c using standard notation. A method was developed to use the FFT phase difference between the incident and scattered signals at the interface to determine the time-delay as a function of frequency, the backscattering coefficient M versus frequency, a particle size distribution, and an average value of the diameter. Experimental average diameter results are shown in the square brackets for nominal particle sizes: (1) 1588-μm acrylic spheres [1564 μm], (2) polystyrene spheres for diameters from 200 μm to 500 μm [260 μm-536 μm], (3) suspended slurry of 250-300 μm polystyrene spheres at 2.25 MHz [253 μm], (4) 794 μm [759 μm] and 1588-μm [1623 μm] Teflon spheres, (5) 1588-μm stainless steel spheres [1674 μm], and (6) suspended slurry of 250-300 μm polystyrene spheres [275 μm] at 3.5 MHz for seven volume fractions. Density and particle size measurements were obtained for the latter. For the density measurement, the FFT amplitude of the scattered signal was summed from 2 to 4 MHz for each slurry. A plot of the square root of the FFT-amplitude-sum versus the volume fraction yields a straight line, passing through the origin. A calibration of the experimental setup is obtained by fitting a straight line through the data with error bars. Thus, the volume fraction for a slurry of unknown concentration can be determined by measuring the FFT-amplitude-sum. The density

  6. Radiation from particles moving in small-scale magnetic fields created in solid-density laser-plasma laboratory experiments

    NASA Astrophysics Data System (ADS)

    Keenan, Brett D.; Medvedev, Mikhail V.

    2015-11-01

    Plasmas created by high-intensity lasers are often subject to the formation of kinetic-streaming instabilities, such as the Weibel instability, which lead to the spontaneous generation of high-amplitude, tangled magnetic fields. These fields typically exist on small spatial scales, i.e., "sub-Larmor scales." Radiation from charged particles moving through small-scale electromagnetic (EM) turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation, and it carries valuable information on the statistical properties of the EM field structure and evolution. Consequently, this radiation from laser-produced plasmas may offer insight into the underlying electromagnetic turbulence. Here, we investigate the prospects for, and demonstrate the feasibility of, such direct radiative diagnostics for mildly relativistic, solid-density laser plasmas produced in lab experiments.

  7. Particle Size Distributions Obtained Through Unfolding 2D Sections: Towards Accurate Distributions of Nebular Solids in the Allende Meteorite

    NASA Technical Reports Server (NTRS)

    Christoffersen, P. A.; Simon, Justin I.; Ross, D. K.; Friedrich, J. M.; Cuzzi, J. N.

    2012-01-01

    Size distributions of nebular solids in chondrites suggest an efficient sorting of these early forming objects within the protoplanetary disk. The effect of this sorting has been documented by investigations of modal abundances of CAIs (e.g., [1-4]) and chondrules (e.g., [5-8]). Evidence for aerodynamic sorting in the disk is largely qualitative, and needs to be carefully assessed. It may be a way of concentrating these materials into planetesimal-mass clumps, perhaps 100 fs of ka after they formed. A key parameter is size/density distributions of particles (i.e., chondrules, CAIs, and metal grains), and in particular, whether the radius-density product (rxp) is a better metric for defining the distribution than r alone [9]. There is no consensus between r versus rxp based models. Here we report our initial tests and preliminary results, which when expanded will be used to test the accuracy of current dynamical disk models.

  8. Lidar observations of Arctic polar stratospheric clouds, 1988 - Signature of small, solid particles above the frost point

    NASA Technical Reports Server (NTRS)

    Poole, L. R.; Osborn, M. T.; Hunt, W. H.

    1988-01-01

    The paper presents recent (January 1988) Arctic airborne lidar data which suggest that Type I polar stratospheric clouds (PSCs) are composed of small solid particles with radii on the order of 0.5 micron. PSCs were observed remotely in the 21-24 km altitude range north of Greenland during a round-trip flight from Andenes, Norway on January 29, 1988, aboard the NASA Wallops Flight Facility P-3 Orion aircraft. Synoptic analyses at the 30-mb level show local temperatures of 191-193 K, which are well above the estimated frost point temperature of 185 K; this suggests that the PSCs were probably of the binary HNO3-H2O (Type I) class.

  9. Radiation from particles moving in small-scale magnetic fields created in solid-density laser-plasma laboratory experiments

    SciTech Connect

    Keenan, Brett D. Medvedev, Mikhail V.

    2015-11-15

    Plasmas created by high-intensity lasers are often subject to the formation of kinetic-streaming instabilities, such as the Weibel instability, which lead to the spontaneous generation of high-amplitude, tangled magnetic fields. These fields typically exist on small spatial scales, i.e., “sub-Larmor scales.” Radiation from charged particles moving through small-scale electromagnetic (EM) turbulence has spectral characteristics distinct from both synchrotron and cyclotron radiation, and it carries valuable information on the statistical properties of the EM field structure and evolution. Consequently, this radiation from laser-produced plasmas may offer insight into the underlying electromagnetic turbulence. Here, we investigate the prospects for, and demonstrate the feasibility of, such direct radiative diagnostics for mildly relativistic, solid-density laser plasmas produced in lab experiments.

  10. Growth behavior of LiMn2O4 particles formed by solid-state reactions in air and water vapor

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Yanagisawa, Kazumichi; Murakami, Takeshi; Naito, Makio

    2016-11-01

    Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn2O4 particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn2O4 particles in air and water vapor atmospheres as model reactions; LiMn2O4 is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO3 precursor impregnated with LiOH, LiMn2O4 spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled.

  11. Analysis of suspended solids by single-particle scattering. [for Lake Superior pollution monitoring

    NASA Technical Reports Server (NTRS)

    Diehl, S. R.; Smith, D. T.; Sydor, M.

    1979-01-01

    Light scattering by individual particulates is used in a multiple-detector system to categorize the composition of suspended solids in terms of broad particulate categories. The scattering signatures of red clay and taconite tailings, the two primary particulate contaminants in western Lake Superior, along with two types of asbestiform fibers, amphibole and chrysolite, were studied in detail. A method was developed to predict the concentration of asbestiform fibers in filtration plant samples for which electron microscope analysis was done concurrently. Fiber levels as low as 50,000 fibers/liter were optically detectable. The method has application in optical categorization of samples for remote sensing purposes and offers a fast, inexpensive means for analyzing water samples from filtration plants for specific particulate contaminants.

  12. Time dependence of solid-particle impingement erosion of an aluminum alloy

    NASA Technical Reports Server (NTRS)

    Veerabhadrarao, P.; Buckley, D. H.

    1983-01-01

    Erosion studies were conducted on 6061-T6511 aluminum alloy by using jet impingement of glass beads and crushed glass particles to investigate the influence of exposure time on volume loss rate at different pressures. The results indicate a direct relationship between erosion-versus-time curves and pitmorphology (width, depth, and width-depth ratio)-versus-time curves for both glass forms. Extensive erosion data from the literature were analyzed to find the variations of erosion-rate-versus-time curves with respect to the type of device, the size and shape of erodent particles, the abrasive charge, the impact velocity, etc. Analysis of the experimental data, obtained with two forms of glass, resulted in three types of erosion-rate-versus-time curves: (1) curves with incubation, acceleration, and steadystate periods (type 1); (2) curves with incubation, acceleration, decleration, and steady-state periods (type 3); and (3) curves with incubation, acceleration, peak rate, and deceleration periods (type 4). The type 4 curve is a less frequently seen curve and was not reported in the literature. Analysis of extensive literature data generally indicated three types of erosion-rate-versus-time curves. Two types (types 1 and 3) were observed in the present study; the third type involves incubation (and deposition), acceleration, and steady-state periods (type 2). Examination of the extensive literature data indicated that it is absolutely necessary to consider the corresponding stages or periods of erosion in correlating and characterizing erosion resistance of a wide spectrum of ductile materials.

  13. Solid particle impingement erosion characteristics of cylindrical surfaces, pre-existing holes and slits

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Buckley, D. H.

    1983-01-01

    The erosion characteristics of aluminum cylinders sand-blasted with both spherical and angular erodent particles were studied and compared with results from previously studied flat surfaces. The cylindrical results are discussed with respect to impact conditions. The relationship between erosion rate and pit morphology (width, depth, and width to depth ratio) is established. The aspects of (1) erosion rate versus time curves on cylindrical surfaces; (2) long-term exposures; and (3) erosion rate versus time curves with spherical and angular particles are presented. The erosion morphology and characteristics of aluminum surfaces with pre-existing circular cylindrical and conical holes of different sizes were examined using weight loss measurements, scanning electron microscopy, a profilometer, and a depth gage. The morphological features (radial and concentric rings) are discussed with reference to flat surfaces, and the erosion features with spherical microglass beads. The similarities and differences of erosion and morphological features are highlighted. The erosion versus time curves of various shapes of holes are discussed and are compared with those of a flat surface. The erosion process at slits is considered.

  14. The SPRITE and POS-SPRITE user report: An extensible calculation of particle, positron and electron implantation in solids

    SciTech Connect

    Ritley, K.A.; Ghosh, V.J.; Lynn, K.G.; McKewown, M.; Welch, D.O.

    1997-10-20

    SPRITE (Simulation of Particle Reemission, Implantation and Transmission--Extensible) is a Fortran computer program designed to model the transport of a stream of energetic particles as they scatter through a solid or multilayer. SPRITE is intended to be a user-friendly and easily-extensible engine for performing basic transport calculations, and SPRITE incorporates such physics as is required to simulate the transport process, but specifically omits the details of the scattering mechanisms. PSPRITE is a Fortran computer program, built around the SPRITE transport engine and incorporating physical information necessary for modeling the implantation and thermalization of a stream of positrons or electrons with a solid. This document is intended to be the primary source of information and the only operations manual for SPRITE and the POS-SPRITE family of programs. This information includes the mode of operation of SPRITE, the format of the required and optional file types, as well as information about the output and results of the calculation. Information about installing and running these programs on a variety of computer systems will not be addressed in this report. Such information is rapidly expanding as these programs are adapted to run on different platforms, and thus the user can expect such information to be contained with the source code distribution set. Detailed information about the calculations of the structure of the POS-SPRITE programs are provided in this report, but detailed benchmark comparisons between the output of these calculations and experimental data are an active topic of research, and they refer the reader to the published literature for this information.

  15. Gallic Acid Production with Mouldy Polyurethane Particles Obtained from Solid State Culture of Aspergillus niger GH1.

    PubMed

    Mata-Gómez, Marco; Mussatto, Solange I; Rodríguez, Raul; Teixeira, Jose A; Martinez, Jose L; Hernandez, Ayerim; Aguilar, Cristóbal N

    2015-06-01

    Gallic acid production in a batch bioreactor was evaluated using as catalytic material the mouldy polyurethane solids (MPS) obtained from a solid-state fermentation (SSF) bioprocess carried out for tannase production by Aspergillus niger GH1 on polyurethane foam powder (PUF) with 5 % (v/w) of tannic acid as inducer. Fungal biomass, tannic acid consumption and tannase production were kinetically monitored. SSF was stopped when tannase activity reached its maximum level. Effects of washing with distilled water and drying on the tannase activity of MPS were determined. Better results were obtained with dried and washed MPS retaining 84 % of the tannase activity. Maximum tannase activity produced through SSF after 24 h of incubation was equivalent to 130 U/gS with a specific activity of 36 U/mg. The methylgallate was hydrolysed (45 %) in an easy, cheap and fast bioprocess (30 min). Kinetic parameters of tannase self-immobilized on polyurethane particles were calculated to be 5 mM and 04.1 × 10(-2) mM/min for K M and V max, respectively. Results demonstrated that the MPS, with tannase activity, can be successfully used for the production of the antioxidant gallic acid from methyl-gallate substrate. Direct use of PMS to produce gallic acid can be advantageous as no previous extraction of enzyme is required, thus reducing production costs.

  16. Effect of physical state and particle size distribution on dissolution enhancement of nimodipine/PEG solid dispersions prepared by melt mixing and solvent evaporation.

    PubMed

    Papageorgiou, George Z; Bikiaris, Dimitrios; Karavas, Evagelos; Politis, Stavros; Docoslis, Aristides; Park, Yong; Stergiou, Anagnostis; Georgarakis, Emmanouel

    2006-10-06

    The physical structure and polymorphism of nimodipine were studied by means of micro-Raman, WAXD, DSC, and SEM for cases of the pure drug and its solid dispersions in PEG 4000, prepared by both the hot-melt and solvent evaporation methods. The dissolution rates of nimodipine/PEG 4000 solid dispersions were also measured and discussed in terms of their physicochemical characteristics. Micro-Raman and WAXD revealed a significant amorphous portion of the drug in the samples prepared by the hot-melt method, and that saturation resulted in local crystallization of nimodipine forming, almost exclusively, modification I crystals (racemic compound). On the other hand, mainly modification II crystals (conglomerate) were observed in the solid dispersions prepared by the solvent evaporation method. However, in general, both drug forms may appear in the solid dispersions. SEM and HSM microscopy studies indicated that the drug particle size increased with drug content. The dissolution rates were substantially improved for nimodipine from its solid dispersions compared with the pure drug or physical mixtures. Among solid dispersions, those resulting from solvent coevaporation exhibited a little faster drug release at drug concentrations lower than 20 wt%. Drug amorphization is the main reason for this behavior. At higher drug content the dissolution rates became lower compared with the samples from melt, due to the drug crystallization in modification II, which results in higher crystallinity and increased particle size. Overall, the best results were found for low drug content, for which lower drug crystallinity and smaller particle size were observed.

  17. Characterization of solid particle erosion resistance of ductile metals based on their properties

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Buckley, D. H.

    1985-01-01

    This paper presents experimental results pertaining to spherical glass bead and angular crushed glass particle impingement. A concept of energy absorption to explain the failure of material is proposed and is correlated with the erosion characteristics of several pure metals. Analyses of extensive erosion data indicate that the properties - surface energy, specific melting energy, strain energy, melting point, bulk modulus, hardness, atomic volume - and the product of the parameters - linear coefficient of thermal expansion x bulk modulus x temperature rise required for melting, and ultimate resilience x hardness - exhibit the best correlations. The properties of surface energy and atomic volume are suggested for the first time for correlation purposes and are found to correlate well with erosion rates at different angles of impingement. It further appears that both energy and thermal properties contribute to the total erosion.

  18. The Transformation of Solid Atmospheric Particles into Liquid Droplets Through Heterogeneous Chemistry: Laboratory Insights into the Processing of Calcium Containing Mineral Dust Aerosol in the Troposphere

    SciTech Connect

    Krueger, Brenda J.; Grassian, Vicki H.; Laskin, Alexander; Cowin, James P.

    2003-02-15

    [1] Individual calcium carbonate particles reacted with gas- phase nitric acid at 293 K have been followed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) analysis as a function of time and relative humidity (RH). The rate of calcium carbonate to calcium nitrate conversion is significantly enhanced in the presence of water vapor. The SEM images clearly show that solid CaCO3 particles are converted to spherical droplets as the reaction proceeds. The process occurs through a two-step mechanism involving the conversion of calcium carbonate into calcium nitrate followed by the deliquescence of the calcium nitrate product. The change in phase of the particles and the significant reactivity of nitric acid and CaCO3 at low RH are a direct result of the deliquescence of the product at low RH. This is the first laboratory study to show the phase transformation of solid particles into liquid droplets through heterogeneous chemistry.

  19. Mixed O/W emulsions stabilized by solid particles: a model system for controlled mass transfer triggered by surfactant addition.

    PubMed

    Drelich, Audrey; Grossiord, Jean-Louis; Gomez, François; Clausse, Danièle; Pezron, Isabelle

    2012-11-15

    This article deals with a model mixed oil-in-water (O/W) emulsion system developed to study the effect of surfactants on mass transfer between dispersed oil droplets of different composition. In this purpose, our goal was to formulate O/W emulsions without any surface active agents as stabilizer, which was achieved by replacing surfactants by a mixture of hydrophilic/hydrophobic silica particles. Then, to study the specific role of surfactants in the oil transfer process, different types and concentrations of surfactants were added to the mixed emulsion after its preparation. In such a way, the same original emulsion can be used for all experiments and the influence of various surface active molecules on the oil transfer mechanism can be directly studied. The model mixed emulsion used consists of a mixture of hexadecane-in-water and tetradecane-in-water emulsions. The transfer between tetradecane and hexadecane droplets was monitored by using differential scanning calorimetry, which allows the detection of freezing and melting signals characteristic of the composition of the dispersed oil droplets. The results obtained showed that it is possible to trigger the transfer of tetradecane towards hexadecane droplets by adding surfactants at concentrations above their critical micellar concentration, measured in presence of solid particles, through micellar transport mechanism. PMID:22909967

  20. Enrichment of heavy metals in fine particles of municipal solid waste incinerator (MSWI) fly ash and associated health risk.

    PubMed

    Zhou, Jizhi; Wu, Simiao; Pan, Yun; Zhang, Lingen; Cao, Zhenbang; Zhang, Xiaoqiao; Yonemochi, Shinichi; Hosono, Shigeo; Wang, Yao; Oh, Kokyo; Qian, Guangren

    2015-09-01

    During the pretreatment and recycling processes, the re-suspended dust from municipal solid waste incinerator (MSWI) fly ash might pose a significant health risk to onsite workers due to its toxic heavy metal content. In this work, the morphological and mineralogical characteristics of fly ash in different particle sizes are presented. The concentrations of seven trace elements (Zn, Pb, Cu, Cd, Cr, Fe and Mn) in these samples were determined. The results show that volatile metals, such as Zn, Pb, Cu and Cd, were easily concentrated in the fine particles, especially in Dp2.5-1 and Dp1, with soluble and exchangeable substances as the main chemical species. The health risk assessment illustrated that the cumulative hazard indexes for non-carcinogenic metals in Dp10-5, Dp5-2.5, Dp2.5-1, and Dp1 were 1.69, 1.41, 1.78 and 2.64, respectively, which were higher than the acceptable threshold values (1.0). The cumulative carcinogenic risk was also higher than the threshold value (10(-6)). For the onsite workers, the relatively apparent non-carcinogenic and carcinogenic effects were from Pb and Cr, respectively. The above findings suggest that fine-grained fly ash contained a considerable amount of heavy metals and exhibited a great health risk. PMID:26148642

  1. A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling

    SciTech Connect

    Schneider, P. A.; Blank, H.; Geiger, B.; Mank, K.; Martinov, S.; Ryter, F.; Weiland, M.; Weller, A.

    2015-07-15

    At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account.

  2. A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling.

    PubMed

    Schneider, P A; Blank, H; Geiger, B; Mank, K; Martinov, S; Ryter, F; Weiland, M; Weller, A

    2015-07-01

    At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account. PMID:26233384

  3. A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling

    NASA Astrophysics Data System (ADS)

    Schneider, P. A.; Blank, H.; Geiger, B.; Mank, K.; Martinov, S.; Ryter, F.; Weiland, M.; Weller, A.

    2015-07-01

    At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account.

  4. A new compact solid-state neutral particle analyser at ASDEX Upgrade: Setup and physics modeling.

    PubMed

    Schneider, P A; Blank, H; Geiger, B; Mank, K; Martinov, S; Ryter, F; Weiland, M; Weller, A

    2015-07-01

    At ASDEX Upgrade (AUG), a new compact solid-state detector has been installed to measure the energy spectrum of fast neutrals based on the principle described by Shinohara et al. [Rev. Sci. Instrum. 75, 3640 (2004)]. The diagnostic relies on the usual charge exchange of supra-thermal fast-ions with neutrals in the plasma. Therefore, the measured energy spectra directly correspond to those of confined fast-ions with a pitch angle defined by the line of sight of the detector. Experiments in AUG showed the good signal to noise characteristics of the detector. It is energy calibrated and can measure energies of 40-200 keV with count rates of up to 140 kcps. The detector has an active view on one of the heating beams. The heating beam increases the neutral density locally; thereby, information about the central fast-ion velocity distribution is obtained. The measured fluxes are modeled with a newly developed module for the 3D Monte Carlo code F90FIDASIM [Geiger et al., Plasma Phys. Controlled Fusion 53, 65010 (2011)]. The modeling allows to distinguish between the active (beam) and passive contributions to the signal. Thereby, the birth profile of the measured fast neutrals can be reconstructed. This model reproduces the measured energy spectra with good accuracy when the passive contribution is taken into account.

  5. Polymerizable gemini surfactants at solid/solution interfaces: adsorption and polymerization on melamine formaldehyde particles and capsule fabrication.

    PubMed

    Sakai, Kenichi; Izumi, Keiko; Sakai, Hideki; Abe, Masahiko

    2010-03-15

    Organic capsules have been fabricated via three steps, by using the polymerizable gemini surfactant (1,2-bis(dimethyl(11-methacryloyloxy)undecylammonio) hexane dibromide, PC11-6-11) as a single wall component. In the first fabrication step, the surfactant spontaneously adsorbs on acid-dissolvable melamine formaldehyde (MF) particles in aqueous media. The adsorption isotherm data reveal that the adsorbed amount of PC11-6-11 (per chain) is greater than that of the corresponding monomeric surfactant ((11-methacryloyloxy)undecyltrimethylammonium bromide, PC11), resulting from the greater intermolecular association of PC11-6-11 at the solid/solution interface. The closely packed adsorbed layer of PC11-6-11 provides an opportunity to give a polymer thin film, as a result of in situ photo-polymerization on MF particles (in the second fabrication step) and subsequent acid dissolution of the core MF particles (in the third fabrication step). The dynamic light scattering (DLS) measurements have shown that the apparent hydrodynamic diameter of PC11-6-11 capsules is reversibly changed in response to a change in ionic strength: the increased background electrolyte concentration results in deswelling of the capsules, and vice versa. It seems likely that this swelling/deswelling behavior is primarily driven by the electrostatic interaction between quaternary ammonium groups within the polymerized film. We have also studied the capture and release capabilities of glucose into/from the capsule core and found that (i) glucose is encapsulated into the capsule core at high electrolyte concentrations and (ii) the glucose molecules encapsulated into the core are gradually released when the outer electrolyte solution is replaced by pure water. We believe, therefore, that the PC11-6-11 capsules fabricated here are useful as stimulus-responsive smart vehicles.

  6. Particle generator

    DOEpatents

    Hess, Wayne P.; Joly, Alan G.; Gerrity, Daniel P.; Beck, Kenneth M.; Sushko, Peter V.; Shlyuger, Alexander L.

    2005-06-28

    Energy tunable solid state sources of neutral particles are described. In a disclosed embodiment, a halogen particle source includes a solid halide sample, a photon source positioned to deliver photons to a surface of the halide, and a collimating means positioned to accept a spatially defined plume of hyperthermal halogen particles emitted from the sample surface.

  7. The Orion Exploration Flight Test Post Flight Solid Particle Flight Environment Inspection and Analysis

    NASA Technical Reports Server (NTRS)

    Miller, Joshua E.

    2016-01-01

    Orbital debris in the millimeter size range can pose a hazard to current and planned spacecraft due to the high relative impact speeds in Earth orbit. Fortunately, orbital debris has a relatively short life at lower altitudes due to atmospheric effects; however, at higher altitudes orbital debris can survive much longer and has resulted in a band of high flux around 700 to 1,500 km above the surface of the Earth. While large orbital debris objects are tracked via ground based observation, little information can be gathered about small particles except by returned surfaces, which until the Orion Exploration Flight Test number one (EFT-1), has only been possible for lower altitudes (400 to 500 km). The EFT-1 crew module backshell, which used a porous, ceramic tile system with surface coatings, has been inspected post-flight for potential micrometeoroid and orbital debris (MMOD) damage. This paper describes the pre- and post-flight activities of inspection, identification and analysis of six candidate MMOD impact craters from the EFT-1 mission.

  8. A two-dimensional Segmented Boundary Algorithm for complex moving solid boundaries in Smoothed Particle Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Khorasanizade, Sh.; Sousa, J. M. M.

    2016-03-01

    A Segmented Boundary Algorithm (SBA) is proposed to deal with complex boundaries and moving bodies in Smoothed Particle Hydrodynamics (SPH). Boundaries are formed in this algorithm with chains of lines obtained from the decomposition of two-dimensional objects, based on simple line geometry. Various two-dimensional, viscous fluid flow cases have been studied here using a truly incompressible SPH method with the aim of assessing the capabilities of the SBA. Firstly, the flow over a stationary circular cylinder in a plane channel was analyzed at steady and unsteady regimes, for a single value of blockage ratio. Subsequently, the flow produced by a moving circular cylinder with a prescribed acceleration inside a plane channel was investigated as well. Next, the simulation of the flow generated by the impulsive start of a flat plate, again inside a plane channel, has been carried out. This was followed by the study of confined sedimentation of an elliptic body subjected to gravity, for various density ratios. The set of test cases was completed with the simulation of periodic flow around a sunflower-shaped object. Extensive comparisons of the results obtained here with published data have demonstrated the accuracy and effectiveness of the proposed algorithms, namely in cases involving complex geometries and moving bodies.

  9. Damage mechanism involved in the solid particle erosion of CVD diamond

    NASA Astrophysics Data System (ADS)

    Davies, Alun R.; Field, John E.

    2001-09-01

    Sophisticated electro-optic sensors are employed on aircraft and missiles, and it is essential to protect them from relatively high-speed impacts with airborne dust particles. A loss in transmission caused by such an event can impair guidance, and catastrophic failure may occur. Protection is afforded by the installation of a hard cover that is transparent in the relevant regime. Diamond is potentially by far the most attractive window material due to excellent optical and mechanical properties, but it is difficult to shape. Chemical vapor deposited (CVD) diamond is a polycrystalline synthetic with properties that approach those of single crystal diamond, and it can be more easily shaped. The aims of the present research were to quantify the erosion and transmission losses, and to understand the material removal mechanisms involved. Steady-state erosion rates were obtained for CVD diamond of different grain sizes, using 300-600 micrometers quartz erodent at velocities between 60 and 140 m/s. Images of CVD diamond at various stages of erosion, obtained using an optical microscope and an environmental scanning electron microscope (ESEM), reveal that erosion initially occurs at grain boundaries and that so-called micro-features also have some influence on erosion.

  10. Measuring and modeling solids movement in a large, cold fluidized bed test facility. Second quarterly report, January 1, 1980-March 31, 1980

    SciTech Connect

    Fitzgerald, T. J.; Mrazek, R. V.; Crane, S. D.

    1980-03-01

    The plume model is developed to represent a tube-filled AFBC with large particles, in which air-entrained coal enters in a number of feed ports from below. It assumes that the volatiles are rapidly released from the coal at the feed entry ports to rise as plumes of combustible vapors. Graphs have been prepared to display the predictions of this model for narrow size cuts of a typical coal feed. For a feed of wide size distribution, use these single size charts and properly sum. The lowest carbon efficiency always comes with an intermediate size of feed coal, not with very large or very small feed sizes. Thus the coal feed to the AFBC should try to avoid this critical size. The plume behavior, whether it breaks the surface of the bed, the temperature jump above the bed, concentration variations across the bed, etc., are all governed by one dimensionless group HD/u/sub 0/L/sub 2//sup 2/, which depends primarily on the spacing of feed ports in the bed. For a given coal feed, the carbon efficiency depends only on superficial gas velocity in the bed, the excess air, and elutriation rate constant. A special case and simplification of this model views the coal as being uniformly distributed all over the bed before the volatiles are released. Here analysis is very much simpler, not involving plumes and no volatiles leaving the bed. This plumeless model should reasonably represent AFBC using large feed particles, introduced across the top of the bed and then rapidly mixed by large scale convective flow of solids. The analysis shows that, even in beds with plumes, the simpler plumeless model can be used with negligible error to calculate carbon efficiency; for volatile efficiency, temperature jumps and composition variations across the bed, the complete plume model must be used.

  11. Movement Disorders

    MedlinePlus

    ... want them to. If you have a movement disorder, you experience these kinds of impaired movement. Dyskinesia ... and is a common symptom of many movement disorders. Tremors are a type of dyskinesia. Nerve diseases ...

  12. An Integrated Instrumentation System for Velocity, Concentration and Mass Flow Rate Measurement of Solid Particles Based on Electrostatic and Capacitance Sensors.

    PubMed

    Li, Jian; Kong, Ming; Xu, Chuanlong; Wang, Shimin; Fan, Ying

    2015-12-10

    The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within -3%-8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s.

  13. An Integrated Instrumentation System for Velocity, Concentration and Mass Flow Rate Measurement of Solid Particles Based on Electrostatic and Capacitance Sensors

    PubMed Central

    Li, Jian; Kong, Ming; Xu, Chuanlong; Wang, Shimin; Fan, Ying

    2015-01-01

    The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within −3%–8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s. PMID:26690434

  14. Nanoscale science and engineering forum (706c) design of solid lipid particles with iron oxide quantum dots for the delivery of therapeutic agents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solid lipid particles provide a method to encapsulate and control the release of drugs in vivo but lack the imaging capability provided by CdS quantum dots. This shortcoming was addressed by combining these two technologies into a model system that uses iron oxide as a non-toxic imaging component in...

  15. Solids Accumulation Scouting Studies

    SciTech Connect

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

    2012-09-26

    the solids mounds. The mounds were scanned after tank supernatant was removed. 4. Core sampler to determine the stainless steel solids distribution within the solids mounds. This sampler was designed and built to remove small sections of the mounds to evaluate concentrations of the stainless steel solids at different special locations. 5. Computer driven positioner that placed the laser rangefinders and the core sampler in appropriate locations over solids mounds that accumulated on the bottom of a scaled staging tank where mixing is poor. These devices and techniques were effective to estimate the movement, location, and concentrations of the solids representing heavier particles and could perform well at a larger scale The experiment contained two campaigns with each comprised of ten cycles to fill and empty the scaled staging tank. The tank was filled without mixing, but emptied, while mixing, in seven batches; the first six were of equal volumes of 13.1 gallons each to represent the planned fullscale batches of 145,000 gallons, and the last, partial, batch of 6.9 gallons represented a full-scale partial batch of 76,000 gallons that will leave a 72-inch heel in the staging tank for the next cycle. The sole difference between the two campaigns was the energy to mix the scaled staging tank, i.e., the nozzle velocity and jet rotational speed of the two jet pumps. Campaign 1 used 22.9 ft/s, at 1.54 rpm based on past testing and Campaign 2 used 23.9 ft/s at 1.75 rpm, based on visual observation of minimum velocity that allowed fast settling solids, i.e., sand and stainless steel, to accumulate on the scaled tank bottom.

  16. Solids fluidizer-injector

    DOEpatents

    Bulicz, Tytus R.

    1990-01-01

    An apparatus and process for fluidizing solid particles by causing rotary motion of the solid particles in a fluidizing chamber by a plurality of rotating projections extending from a rotatable cylinder end wall interacting with a plurality of fixed projections extending from an opposite fixed end wall and passing the solid particles through a radial feed orifice open to the solids fluidizing chamber on one side and a solid particle utilization device on the other side. The apparatus and process are particularly suited for obtaining intermittent feeding with continual solids supply to the fluidizing chamber. The apparatus and process are suitable for injecting solid particles, such as coal, to an internal combustion engine.

  17. Optimization of a PGSS (particles from gas saturated solutions) process for a fenofibrate lipid-based solid dispersion formulation.

    PubMed

    Pestieau, Aude; Krier, Fabrice; Lebrun, Pierre; Brouwers, Adeline; Streel, Bruno; Evrard, Brigitte

    2015-05-15

    The aim of this study was to develop a formulation containing fenofibrate and Gelucire(®) 50/13 (Gattefossé, France) in order to improve the oral bioavailability of the drug. Particles from gas saturated solutions (PGSS) process was chosen for investigation as a manufacturing process for producing a solid dispersion. The PGSS process was optimized according to the in vitro drug dissolution profile obtained using a biphasic dissolution test. Using a design of experiments approach, the effects of nine experimental parameters were investigated using a PGSS apparatus provided by Separex(®) (Champigneulles, France). Within the chosen experimental conditions, the screening results showed that the drug loading level, the autoclave temperature and pressure, the connection temperature and the nozzle diameter had a significant influence on the dissolution profile of fenofibrate. During the optimization step, the three most relevant parameters were optimized using a central composite design, while other factors remained fixed. In this way, we were able to identify the optimal production conditions that would deliver the highest level of fenofibrate in the organic phase at the end of the dissolution test. The closeness between the measured and the predicted optimal dissolution profiles in the organic phase demonstrated the validity of the statistical analyses.

  18. Influence of changing particle structure on the rate of gas-solid gasification reactions. Final report, July 1981-March 1984

    SciTech Connect

    Not Available

    1984-04-04

    The objetive of this work is to determine the changes in the particle structure of coal as it undergoes the carbon/carbon dioxide reaction (C + CO/sub 2/ ..-->.. 2CO). Char was produced by heating the coal at a rate of 25/sup 0/C/min to the reaction temperatures of 800/sup 0/C, 900/sup 0/C, 1000/sup 0/C and 1100/sup 0/C. The changes in surface area and effective diffusivity as a result of devolitization were determined. Changes in effective diffusivity and surface area as a function of conversion have been measured for reactions conducted at 800, 900, 1000 and 1100/sup 0/C for Wyodak coal char. The surface areas exhibit a maximum as a function of conversion in all cases. For the reaction at 1000/sup 0/C the maximum in surface area is greater than the maxima determined at all other reaction temperatures. Thermogravimetric rate data were obtained for five coal chars; Wyodak, Wilcox, Cimmeron, Illinois number 6 and Pittsburgh number 6 over the temperature range 800-1100/sup 0/C. All coal chars exhibit a maximum in reaction rate. Five different models for gas-solid reactions were evaluated. The Bhatia/Perlmutter model seems to best represent the data. 129 references, 67 figures, 37 tables.

  19. Determination of five pyrethroids in tea drinks by dispersive solid phase extraction with polyaniline-coated magnetic particles.

    PubMed

    Wang, Yuanpeng; Sun, Ying; Gao, Yan; Xu, Bo; Wu, Qiong; Zhang, Hanqi; Song, Daqian

    2014-02-01

    The polyaniline-coated magnetic particles with bowl-shaped morphology (Fe3O4/C/PANI microbowls) were successfully prepared and characterized by scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. The prepared microbowls were used as the magnetic adsorbent in dispersive solid phase extraction of five pyrethroids, including cyhalothrin, beta-cypermethrin, esfenvalerate, permethrin and bifenthrin in plain tea drinks. The effects of experiment factors, including amount of Fe3O4/C/PANI microbowls, pH value, ultrasound extraction time and desorption conditions, were investigated. The extraction recoveries obtained with 8 mg of magnetic microbowls were satisfactory, and the microbowls can be reused after easy washing. Thus, a simple, selective and effective method for the determination of the pyrethroids was established successfully. The results showed that the method had good linearity (r=0.9992-0.9998), and the limits of detections (LODs) were from 0.025 to 0.032 ng mL(-1). The intra-day and inter-day relative standard deviations (RSDs) were in the range of 2.4-6.1% and 3.5-8.8%, respectively. Recoveries obtained by analyzing the real tea drinks were in the range of 72.1-118.4%.

  20. Room-temperature storage of microalgae in water-in-oil emulsions: influence of solid particle type and concentration in the oil phase.

    PubMed

    Fernández, Lorena; Scher, Herbert; Jeoh, Tina; VanderGheynst, Jean S

    2015-12-01

    Water-in-oil emulsions containing silica nanoparticles (Aerosil R974) have the potential to stabilize microalgae for long-term storage. Studies were completed to determine if smectite clays could be used as an alternative to Aerosil R974. Emulsions were prepared with Aerosil R974, and hectorite and bentonite clays in the continuous phase and Chlorella sorokiniana was added to the aqueous phase to monitor the effects of solid particles on emulsion stability. Biological stability (cell viability) was determined using cell density measurements, and physical stability was measured from water droplet size distributions obtained by light scattering measurements and by examining phase separation over time. Measurements were also made to determine the effects of particles in the oil phase on emulsion viscosity. Particle concentrations greater than 0.25 wt% in the oil phase were required for maintaining physical stability. In emulsions containing 1 wt% solid particles and microalgae, biological stability of cells could be sustained for 340 days, regardless of particle type. At 1 wt% particles in the oil phase, apparent viscosity was 165% greater for samples containing hectorite and bentonite clays compared to samples containing Aerosil R974. The higher viscosity would need to be considered in large-scale production of emulsions for commercial application.

  1. Easy measurement and analysis method of zeta potential and electrophoretic mobility of water-dispersed colloidal particles by using a self-mixing solid-state laser

    NASA Astrophysics Data System (ADS)

    Sudo, S.; Ohtomo, T.; Otsuka, K.

    2013-08-01

    We describe a highly sensitive method of measuring electrophoretic mobility and zeta potential of water-dispersed colloidal particles by using a self-mixing laser Doppler velocimeter with a laser-diode-pumped, thin-slice solid-state laser with extremely high optical sensitivity. The power spectra of laser output modulated by reinjected laser light scattered by the electrophoretic particles were observed. The power spectrum cannot be described by the well-known formula for translational motion or flowing Brownian motion, i.e., a combination of Doppler shift, diffusion, and translation. The power spectra shape is found to reflect the velocity distribution of electrophoretic particles in a capillary tube due to the electro-osmotic flow contribution. Not only evaluation of the electrophoretic mobility and zeta potential but also the particle diameter undergoing electrophoretic motion can be performed from the shape of the power spectrum.

  2. Relationship Between Particle and Plasma Properties and Coating Characteristics of Samaria-Doped Ceria Prepared by Atmospheric Plasma Spraying for Use in Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Cuglietta, Mark; Kesler, Olivera

    2012-06-01

    Samaria-doped ceria (SDC) has become a promising material for the fabrication of high-performance, intermediate-temperature solid oxide fuel cells (SOFCs). In this study, the in-flight characteristics, such as particle velocity and surface temperature, of spray-dried SDC agglomerates were measured and correlated to the resulting microstructures of SDC coatings fabricated using atmospheric plasma spraying, a manufacturing technique with the capability of producing full cells in minutes. Plasmas containing argon, nitrogen and hydrogen led to particle surface temperatures higher than those in plasmas containing only argon and nitrogen. A threshold temperature for the successful deposition of SDC on porous stainless steel substrates was calculated to be 2570 °C. Coating porosity was found to be linked to average particle temperature, suggesting that plasma conditions leading to lower particle temperatures may be most suitable for fabricating porous SOFC electrode layers.

  3. Direct observation of solid-phase adsorbate concentration profile in powdered activated carbon particle to elucidate mechanism of high adsorption capacity on super-powdered activated carbon.

    PubMed

    Ando, Naoya; Matsui, Yoshihiko; Matsushita, Taku; Ohno, Koichi

    2011-01-01

    Decreasing the particle size of powdered activated carbon (PAC) by pulverization increases its adsorption capacities for natural organic matter (NOM) and polystyrene sulfonate (PSS, which is used as a model adsorbate). A shell adsorption mechanism in which NOM and PSS molecules do not completely penetrate the adsorbent particle and instead preferentially adsorb near the outer surface of the particle has been proposed as an explanation for this adsorption capacity increase. In this report, we present direct evidence to support the shell adsorption mechanism. PAC particles containing adsorbed PSS were sectioned with a focused ion beam, and the solid-phase PSS concentration profiles of the particle cross-sections were directly observed by means of field emission-scanning electron microscopy/energy-dispersive X-ray spectrometry (FE-SEM/EDXS). X-ray emission from sulfur, an index of PSS concentration, was higher in the shell region than in the inner region of the particles. The X-ray emission profile observed by EDXS did not agree completely with the solid-phase PSS concentration profile predicted by shell adsorption model analysis of the PSS isotherm data, but the observed and predicted profiles were not inconsistent when the analytical errors were considered. These EDXS results provide the first direct evidence that PSS is adsorbed mainly in the vicinity of the external surface of the PAC particles, and thus the results support the proposition that the increase in NOM and PSS adsorption capacity with decreasing particle size is due to the increase in external surface area on which the molecules can be adsorbed. PMID:20851447

  4. Effect of Variable Solvents on Particle Size of Geranium Oil-Loaded Solid Lipid Nanoparticle (Ge-SLN) For Mosquito Repellent Applications

    NASA Astrophysics Data System (ADS)

    Asnawi, Syalwati; Aziz, Azila A.; Aziz, Ramlan A.

    2009-06-01

    A new delivery system for insect repellent is proposed by the incorporation of geranium oil into solid lipid nanoparticle (SLN). A variety of solvents which act as co-surfactants, were introduced to increase the particle size of GE-SLN. Ethanol, which has a high boiling point and a long chain alcohol produced larger particle than dichloromethane. The structure of SLN was not stable when methanol and acetone were used as co-solvents. Concentration of solvents can also influence the size of SLN. In vitro release experiments showed that SLN was able to reduce the rapid evaporation of geranium oil.

  5. Fine-particle emissions from solid biofuel combustion studied with single-particle mass spectrometry: Identification of markers for organics, soot, and ash components

    NASA Astrophysics Data System (ADS)

    Pagels, Joakim; Dutcher, Dabrina D.; Stolzenburg, Mark R.; McMurry, Peter H.; GäLli, Markus E.; Gross, Deborah S.

    2013-01-01

    The effects of combustion phase and fuel on smoke particle emissions from a wood stove operated with three different wood fuels and from a corn stove were investigated. A single-particle mass spectrometer (aerosol time of flight mass spectrometer (ATOFMS)) was used for time- and size-resolved chemical signatures and a scanning mobility particle sizer (SMPS) was used for online mobility size distributions. Markers of particle phase organics and elemental carbon, PM1.5, and CO emissions were strongly reduced for the corn stove compared to the wood stove. This is because the more controlled fuel and air supply in the corn stove result in more complete combustion. NOx emissions and particle phase phosphates showed the opposite trend. Marker ions and particle types associated with soot and alkali salts such as potassium chloride and potassium sulfates dominated during flaming combustion and were correlated with increased exhaust temperatures and reduced CO emissions. Marker ions of hydrocarbons and oxidized organics as well as a particle cluster type with a strong organic signature were associated with reduced combustion temperature and increased CO levels, observed during start up from cold stove, addition of fuel, and combustion with reduced air supply. Two different particle types were identified in corn experiments when particles were classified according to mobility before they were measured with the ATOFMS. "Less massive" particles contained mostly ash and soot and had vacuum aerodynamic diameters that were nearly independent of mobility diameter. "More massive" particles had aerodynamic diameters that increased linearly with mobility diameter, indicating approximately spherical shapes, and were hypothesized to consist of organics.

  6. Applications of Defocused Digital Particle Image Velocimetry to Simultaneous Dynamic Three-Dimensional Mapping of Solid Surfaces and Their Induced Flow

    NASA Astrophysics Data System (ADS)

    Castaño Graff, Emilio; Pereira, Francisco; Dabiri, Dana; Gharib, Morteza

    2004-11-01

    DDPIV is a direct extension of DPIV into the third spatial dimension. It is capable of mapping solid surfaces in three dimensions and calculating three-dimensional velocity fields of fluid flows using tracer particles in a pre-determined laser-illuminated volume. Elements belonging to the solid surface can be separated from flow elements through pattern recognition, marker recognition, or optical separation (polarization, color bias, etc.) when necessary, though in more repeatable phenomena the mapping of the surface and flow can be done in separate instances and then combined through phase averaging. Experiments were conducted with a thin, transparent plate flapping in water seeded with tracer particles to demonstrate the viability of this technique.

  7. Bowel Movement

    MedlinePlus

    A bowel movement is the last stop in the movement of food through your digestive tract. Your stool passes out ... rectum and anus. Another name for stool is feces. It is made of what is left after ...

  8. Evaluating of scale-up methodologies of gas-solid spouted beds for coating TRISO nuclear fuel particles using advanced measurement techniques

    NASA Astrophysics Data System (ADS)

    Ali, Neven Y.

    The work focuses on implementing for the first time advanced non-invasive measurement techniques to evaluate the scale-up methodology of gas-solid spouted beds for hydrodynamics similarity that has been reported in the literature based on matching dimensionless groups and the new mechanistic scale up methodology that has been developed in our laboratory based on matching the radial profile of gas holdup since the gas dynamics dictate the hydrodynamics of the gas-solid spouted beds. These techniques are gamma-ray computed tomography (CT) to measure the cross-sectional distribution of the phases' holdups and their radial profiles along the bed height and radioactive particle tracking (RPT) to measure in three-dimension (3D) solids velocity and their turbulent parameters. The measured local parameters and the analysis of the results obtained in this work validate our new methodology of scale up of gas-solid spouted beds by comparing for the similarity the phases' holdups and the dimensionless solids velocities and their turbulent parameters that are non-dimensionalized using the minimum spouting superficial gas velocity. However, the scale-up methodology of gas-solid spouted beds that is based on matching dimensionless groups has not been validated for hydrodynamics similarity with respect to the local parameters such as phases' holdups and dimensionless solids velocities and their turbulent parameters. Unfortunately, this method was validated in the literature by only measuring the global parameters. Thus, this work confirms that validation of the scale-up methods of gas-solid spouted beds for hydrodynamics similarity should reside on measuring and analyzing the local hydrodynamics parameters.

  9. Computational Prediction of Cryogenic Micro-nano Solid Nitrogen Particle Production Using Laval Nozzle for Physical Photo Resist Removal-cleaning Technology

    NASA Astrophysics Data System (ADS)

    Ishimoto, Jun; Abe, Haruto; Ochiai, Naoya

    The fundamental characteristics of the cryogenic single-component micro-nano solid nitrogen (SN2) particle production using super adiabatic Laval nozzle and its application to the physical photo resist removal-cleaning technology are investigated by a new type of integrated measurement coupled computational technique. As a result of present computation, it is found that high-speed ultra-fine SN2 particles are continuously generated due to the freezing of liquid nitrogen (LN2) droplets induced by rapid adiabatic expansion of transonic subcooled two-phase nitrogen flow passing through the Laval nozzle. Furthermore, the effect of SN2 particle diameter, injection velocity, and attack angle to the wafer substrate on resist removal-cleaning performance is investigated in detail by integrated measurement coupled computational technique.

  10. Comparison between Synthesized Lead Particles and Lead Solids Formed on Surfaces in Real Drinking Water Distribution Systems

    EPA Science Inventory

    The objective of this work is to compare the properties of lead solids formed during bench-scale precipitation experiments to solids found on lead pipe removed from real drinking water distribution systems and metal coupons used in pilot scale corrosion testing. Specifically, so...

  11. Investigation of Particle Accumulation, Chemosensitivity and Thermosensitivity for Effective Solid Tumor Therapy Using Thermosensitive Liposomes and Hyperthermia

    PubMed Central

    Lokerse, Wouter J.M.; Bolkestein, Michiel; ten Hagen, Timo L.M.; de Jong, Marion; Eggermont, Alexander M.M.; Grüll, Holger; Koning, Gerben A.

    2016-01-01

    Doxorubicin (Dox) loaded thermosensitive liposomes (TSLs) have shown promising results for hyperthermia-induced local drug delivery to solid tumors. Typically, the tumor is heated to hyperthermic temperatures (41-42 °C), which induced intravascular drug release from TSLs within the tumor tissue leading to high local drug concentrations (1-step delivery protocol). Next to providing a trigger for drug release, hyperthermia (HT) has been shown to be cytotoxic to tumor tissue, to enhance chemosensitivity and to increase particle extravasation from the vasculature into the tumor interstitial space. The latter can be exploited for a 2-step delivery protocol, where HT is applied prior to i.v. TSL injection to enhance tumor uptake, and after 4 hours waiting time for a second time to induce drug release. In this study, we compare the 1- and 2-step delivery protocols and investigate which factors are of importance for a therapeutic response. In murine B16 melanoma and BFS-1 sarcoma cell lines, HT induced an enhanced Dox uptake in 2D and 3D models, resulting in enhanced chemosensitivity. In vivo, therapeutic efficacy studies were performed for both tumor models, showing a therapeutic response for only the 1-step delivery protocol. SPECT/CT imaging allowed quantification of the liposomal accumulation in both tumor models at physiological temperatures and after a HT treatment. A simple two compartment model was used to derive respective rates for liposomal uptake, washout and retention, showing that the B16 model has a twofold higher liposomal uptake compared to the BFS-1 tumor. HT increases uptake and retention of liposomes in both tumors models by the same factor of 1.66 maintaining the absolute differences between the two models. Histology showed that HT induced apoptosis, blood vessel integrity and interstitial structures are important factors for TSL accumulation in the investigated tumor types. However, modeling data indicated that the intraliposomal Dox fraction did not

  12. Effects of hydrodynamic retardation and interparticle interactions on the self-assembly in a drying droplet containing suspended solid particles.

    PubMed

    Lebovka, N I; Khrapatiy, S; Melnyk, R; Vygornitskii, M

    2014-05-01

    Self-assembly of particles, suspended in a drying droplet, were studied by the Monte Carlo method. The Brownian diffusion of particles was simulated accounting for the effect of hydrodynamic retardation and interparticle interactions. The model allowed for explaining formation of the "coffee ring" patterns even without accounting for the radial flows towards the three-phase contact line. Morphologies of the drying patterns and their dependence on interparticle interactions and concentration of particles are discussed. PMID:25353800

  13. Movement - uncontrolled or slow

    MedlinePlus

    Dystonia; Involuntary slow and twisting movements; Choreoathetosis; Leg and arm movements - uncontrollable; Arm and leg movements - uncontrollable; Slow involuntary movements of large muscle groups; Athetoid movements

  14. [Stereotypic movements].

    PubMed

    Fernández-Alvarez, E

    2003-02-01

    Stereotypic movements are repetitive patterns of movement with certain peculiar features that make them especially interesting. Their physiopathology and their relationship with the neurobehavioural disorders they are frequently associated with are unknown. In this paper our aim is to offer a simple analysis of their dominant characteristics, their differentiation from other processes and a hypothesis of the properties of stereotypic movements, which could all set the foundations for research work into their physiopathology.

  15. Preparation, optimization and characterization of bovine lactoferrin-loaded liposomes and solid lipid particles modified by hydrophilic polymers using factorial design.

    PubMed

    Yao, Xudong; Bunt, Craig; Cornish, Jillian; Quek, Siew-Young; Wen, Jingyuan

    2014-05-01

    Bioadhesive liposomes and solid lipid particles (SLPs) modified by pectin and chitosan for oral administration of bovine lactoferrin (bLf) were prepared using a 2(4) full-factorial design to identify the key formulation variables influencing particle size and drug entrapment efficiency (EE). Netlike structures of the polymer-particle mixture consisting of a polymeric network in which multiple particles were imbedded were observed by scanning electron microscopy (SEM). Chemical stability of bLf after encapsulation into pectin- and chitosan-modified liposomes and SLPs was confirmed by Fourier transform infrared spectra (FTIR). Bovine lactoferrin was located within phospholipid bilayer, whereas in SLPs bLf was within the matrix. The crystalline nature of bLf after encapsulation was investigated by differential scanning calorimetry (DSC) of drug-loaded particles, indicating amorphous dispersion of bLf in the polymer-lipid matrix of pectin- and chitosan-modified liposomes and SLPs. In vivo pharmacokinetic investigation of bLf in pectin- and chitosan-modified liposomes and SLPs showed prolonged mean residence time (MRT) of bLf in rat blood and increased the relative bioavailability (Fbio %) by 1.95- to 2.69-fold compared with free bLf. The developed carrier systems are considered to be promising vehicles for oral delivery. PMID:24325576

  16. Experimental analysis of particle sizes for PIV measurements

    NASA Astrophysics Data System (ADS)

    van Overbrüggen, Timo; Klaas, Michael; Soria, Julio; Schröder, Wolfgang

    2016-09-01

    The right choice of seeding particles strongly influences the outcome of a particle-image velocimetry (PIV) measurement. Particles have to scatter enough light to be seen by cameras and follow the flow faithfully. As the flow following behavior depends on the inertia and therefore the size of the particle, smaller particles are desirable. Unfortunately, larger particles possess better light scattering behavior, which is especially important for volumetric PIV measurements. In this paper, the particle response of two exemplary solid particles to an oscillatory air flow created by a piston movement is analyzed and compared to analytic results by Hjelmfelt and Mockros (1966 Appl. Sci. Res. 16 149-61) concerning phase lag and amplitude ratio between particle movement and flow field. To achieve realistic experimental boundary conditions, polydispersed particles are used for the analysis. The analytic results show a strong dependence on the diameter. That is, using the volumetric mean diameter an overestimation of the phase lag of the particles is determined, whereas an underestimation of phase lag is computed for the number mean diameter. Hence, for polydispersed particles a more general analysis than that based on the particle mean diameter is required to determine in detail the particle following behavior.

  17. Experimental analysis of particle sizes for PIV measurements

    NASA Astrophysics Data System (ADS)

    van Overbrüggen, Timo; Klaas, Michael; Soria, Julio; Schröder, Wolfgang

    2016-09-01

    The right choice of seeding particles strongly influences the outcome of a particle-image velocimetry (PIV) measurement. Particles have to scatter enough light to be seen by cameras and follow the flow faithfully. As the flow following behavior depends on the inertia and therefore the size of the particle, smaller particles are desirable. Unfortunately, larger particles possess better light scattering behavior, which is especially important for volumetric PIV measurements. In this paper, the particle response of two exemplary solid particles to an oscillatory air flow created by a piston movement is analyzed and compared to analytic results by Hjelmfelt and Mockros (1966 Appl. Sci. Res. 16 149–61) concerning phase lag and amplitude ratio between particle movement and flow field. To achieve realistic experimental boundary conditions, polydispersed particles are used for the analysis. The analytic results show a strong dependence on the diameter. That is, using the volumetric mean diameter an overestimation of the phase lag of the particles is determined, whereas an underestimation of phase lag is computed for the number mean diameter. Hence, for polydispersed particles a more general analysis than that based on the particle mean diameter is required to determine in detail the particle following behavior.

  18. The Use of Positron Emission Particle Tracking (PEPT) to Study the Movement of Inclusions in Low-Melting-Point Alloy Castings

    NASA Astrophysics Data System (ADS)

    Griffiths, W. D.; Beshay, Y.; Caden, A. J.; Fan, X.; Gargiuli, J.; Leadbeater, T. W.; Parker, D. J.

    2012-04-01

    Positron emission particle tracking (PEPT) employs a radioactive particle that decays by emission of positrons. These positrons collide with local electrons to produce γ-rays emitted at 180 deg to each other; detection of these γ-ray pairs allows the location of the radioactive particle to be identified within a few millimeters. This technique has been tested to determine its applicability to the study of inclusions in cast metals. To use particles representative of inclusion sizes in castings, both alumina particles and particles of an ion exchange resin were employed. These were within a size range of approximately 60 to 100 μm, made radioactive by adsorption and ion exchange techniques, respectively. The radioactive particles, of activity 100 to 1000 μCi, were introduced into tube-shaped castings made from the low-melting-point alloys Field's metal and Lensalloy-136, cast into an acrylic mold. The technique allowed the particle track to be determined from the point of initial introduction to the final resting place of the particle, with increasing reproducibility being obtained as the reproducibility as the casting technique was improved. Experiments in which filters were placed in to the running system showed that the removal of the particles by the filters varied according to the filter pore size.

  19. Hydrodynamic measurement of Brownian particles at a liquid-solid interface by low-coherence dynamic light scattering.

    PubMed

    Ishii, Katsuhiro; Iwai, Toshiaki; Xia, Hui

    2010-03-29

    The hydrodynamics of Brownian particles close to a wall is investigated using low-coherence dynamic light scattering. The diffusion coefficient of the particles in a suspension is measured as a function of distance from the wall. A sudden reduction in the diffusion coefficient near the interface is clearly observed using this method. The theoretically predicted wall-drag effect is experimentally confirmed when the influence of the spatial resolution due to the finite coherence length of the light source is accounted for. The space-dependent dynamics of Brownian particles under the wall-drag effect is obtained for the first time using our spatially resolved dynamic light scattering technique.

  20. Measuring and modeling solids movement in a large, cold fluidized-bed test facility. Fifth quarterly report for the period October 1, 1980-December 31, 1980

    SciTech Connect

    Fitzgerald, T. J.; Mrazek, R. V.; Crane, S. D.

    1980-12-01

    One part representing work on the development and testing of a flowmeter for measuring the motion of solids in a fluidized bed and the second part (a Ph. D. Thesis) on the plume model of fluidized-bed combustion of coal, including its development and validation, have been entered individually into EDB and ERA. (LTN)

  1. A spectroscopic study of heterogeneous reactions of nitrogen oxides and sulfur oxides on solid particles of atmospheric relevance

    NASA Astrophysics Data System (ADS)

    Goodman, Angela Lea

    The purpose of the research described in this thesis is to survey whether nitrogen oxides and sulfur oxides react with mineral dust (SiO2, Al2O3, MgO, CaO, CaCO3, Fe2O 3 and TiO2) and sea salt (NaCl) particles. FT-IR and Diffuse Reflectance UV/Vis spectroscoples were the primary techniques used to probe these reactions. In Chapter III, spectroscopic data show that the reaction between NO 2 and water adsorbed on SiO2 particles yields surface-bound HNO3 and gas-phase HONO. In Chapter IV, spectroscopic data show that HNO3 reacts with CaCO3 Particles to produce surface nitrate and gas-phase CO 2 and H2LO. Under dry conditions, the reaction is limited to the surface of the CaCO3 particles; only the exterior of the CaCO3 particles reacts with HNO3 to form surface nitrate. In the presence of water, bulk reactivity was found showing that the entire particle, both the exterior and interior, is available for reaction with HNO3. Transmission electron microscopy studies revealed that the physiochemical properties of CaCO3 particles change as the particle is processed from CaCO3 to Ca(NO3)2 upon reaction with HNO3 and H2O vapor. The studies in Chapter V are an outgrowth of Chapter IV in that the heterogeneous reaction of HNO3 is investigated on oxide particles (SiO2 , Al2O3, TiO2) Fe2O 3, CaO and MgO). Spectroscopic data reveal that HNO3 weakly adsorbs on SiO2 particles, while HNO3 reacts with the other particles to form surface nitrate. In the presence of water, reaction of HNO3 on MgO and CaO particles was similar to reaction on CaCO 3 particles because bulk reactivity was found. Reaction kinetic measurements show that the HNO3 reaction probability on the oxide particles is enhanced two orders of magnitude when water vapor is present. In the last two chapters, heterogeneous reactions of SO2 (Chapter VI) and photochemical reactions (Chapter VII) are investigated. Spectroscopic data show that SO2 reacts with Al2O3 and MgO to form surface sulfite and weakly adsorbed SO2. Upon

  2. The n-particle picture and the calculation of the electronic structure of atoms, molecules, and solids

    SciTech Connect

    Gonis, A.; Turchi, P.E.A.; Schulthess, T.C.; Ek, J. van

    1997-08-01

    The works referred to above indicate the usefulness of viewing an N-particle system from a higher-dimensional perspective. In doing so, one should attempt to strike a balance between conceptual clarity and computational efficiency, which mitigates against considering calculations in 3n-dimensional space except for rather small values of n. It appears that such a procedure may be profitably employed if a system of N particles were to be considered as consisting of a collection of units or sets, (I{sub k}), each containing n{sub k} particles so that {Sigma}{sub k} n{sub k} = N. The resulting problem associated with these sets of particles that interact with one another is obviously formally identical to the original one. However, it possesses the formal advantage of allowing, in principle, the systematic approach to an exact solution by treating the entire system as a single unit. The operative words here are in principle, as practical applications do not seem to be possible but for the smallest number of particles in a unit, say n = 2 or n = 3. However, in such an implementation, the interparticle correlation is treated directly and explicitly within a unit, resulting in a more accurate treatment of the system the larger the number of particle in a unit.

  3. Airborne measurements of cloud-forming nuclei and aerosol particles in stabilized ground clouds produced by solid rocket booster firings

    NASA Technical Reports Server (NTRS)

    Hindman, E. E., II; Ala, G. G.; Parungo, F. P.; Willis, P. T.; Bendura, R. J.; Woods, D.

    1978-01-01

    Airborne measurements of cloud volumes, ice nuclei and cloud condensation nuclei, liquid particles, and aerosol particles were obtained from stabilized ground clouds (SGCs) produced by Titan 3 launches at Kennedy Space Center, 20 August and 5 September 1977. The SGCs were bright, white, cumulus clouds early in their life and contained up to 3.5 g/m3 of liquid in micron to millimeter size droplets. The measured cloud volumes were 40 to 60 cu km five hours after launch. The SGCs contained high concentrations of cloud condensation nuclei active at 0.2%, 0.5%, and 1.0% supersaturation for periods of three to five hours. The SGCs also contained high concentrations of submicron particles. Three modes existed in the particle population: a 0.05 to 0.1 micron mode composed of aluminum-containing particles, a 0.2 to 0.8 micron mode, and a 2.0 to 10 micron mode composed of particles that contained primarily aluminum.

  4. Forensic analysis of a single particle of partially burnt gunpowder by solid phase micro-extraction-gas chromatography-nitrogen phosphorus detector.

    PubMed

    Burleson, Garrett Lee; Gonzalez, Brittney; Simons, Kelsie; Yu, Jorn C C

    2009-05-29

    Solid phase micro-extraction (SPME) was adopted to extract organic gun shot residues (OGSRs) from a single particle of partially burnt gunpowder. The partially burnt particle samples were collected from gun shot residue (GSR) deposited near the target areas. OGSRs, such as diphenylamine (DPA), methyl centralite (MC), ethyl centralite (EC), from only one single particle of partially burnt gunpowder were successfully extracted by SPME and analyzed by a gas chromatography coupled to a nitrogen phosphorus detector (GC-NPD). The results confirmed that the new extraction procedure is capable of extracting trace amount of MC and EC as signature molecules for the identification of GSR. The method represents a solvent-free extraction as a complementary analytical procedure for the forensic analysis of GSR-related evidences. The new extraction scheme with the capability of analyzing single particle of partially burnt gunpowder can also be applied to the identification of explosive residues, such as in post-blast investigations of improvised explosive devices.

  5. Movement - uncoordinated

    MedlinePlus

    Lack of coordination; Loss of coordination; Coordination impairment; Ataxia; Clumsiness; Uncoordinated movement ... are passed through families (such as congenital cerebellar ataxia, Friedreich ataxia , ataxia - telangiectasia , or Wilson disease ) Multiple ...

  6. Psychogenic Movement

    MedlinePlus

    ... also look for marked improvement in symptoms following psychotherapy, use of a placebo (a medicine with no ... multi-therapy approach to treating psychogenic movement includes psychotherapy, placebo, or suggestion; antidepressants for symptoms related to ...

  7. A study of the nature of solid particle impact and shape on the erosion morphology of ductile metals

    NASA Technical Reports Server (NTRS)

    Rao, P. V.; Young, S. G.; Buckley, D. H.

    1982-01-01

    Impulsive versus steady jet impingement of spherical glass bead particles on metal surfaces was studied using a gas gun facility and a commercial sand blasting apparatus. Crushed glass particles were also used in the sand blasting apparatus as well as glass beads. Comparisons of the different types of erosion patterns were made. Scanning electron microscopy, surface profilometry and energy dispersive X-ray spectroscopy analysis were used to characterize erosion patterns. The nature of the wear can be divided into cutting and deformation, each with its own characteristic features. Surface chemistry analysis indicates the possibility of complex chemical and/or mechanical interactions between erodants and target materials.

  8. Simulations of groundwater-surface water interaction and particle movement due to the effect of weir construction in the sub-watershed of the river Labe in the town of Děčín.

    PubMed

    Matula, S; Mekonnen, G B; Báťková, K; Nešetřil, K

    2014-11-01

    Steady- and transient-state simulations of groundwater flow and particle movement in the sub-watershed of the river Labe in Děčín town was carried out using Visual MODFLOW software. The simulations were performed for calibration and for the scenarios that the change in the water level of the river Labe was undergoing. Steady-state simulation was carried out for the sake of calibration of model outputs. For transient simulation, two different scenarios were considered in order to investigate the response of the aquifer system to the stresses applied on surface water of the river. The simulation results have shown that the surface water and groundwater interactions, and the subsequent particle movement were affected by the stresses applied on the surface water in the river Labe. The first scenario involved the rapid recharge of surface water to the aquifer in the vicinity of the river while particles still move towards the river at the places far away from the river. At the end of the second scenario, particles still tend to move towards the river slowly and finally tend to stay within the aquifer as equilibrium of hydraulic gradient is reached between the surface and groundwater levels. The time series graphs of hydraulic heads at all observation wells show that the groundwater level in the surrounding aquifer rises significantly as a result of recharges from the river. The local water balance of the study area was calculated and expressed as the rates of water entering and leaving the system. At the end of the second scenario, the difference between the rate of flow into and out of the model area was 0.73 m(3) day(-1).

  9. Cellular uptake of beta-carotene from protein stabilized solid lipid nano-particles prepared by homogenization-evaporation method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a homogenization-evaporation method, beta-carotene (BC) loaded nano-particles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, in vitro cytotoxicity, and cel...

  10. Thermophysical properties of gases, liquids, and solids composed of particles interacting with a short-range attractive potential.

    PubMed

    Hess, S; Kröger, M

    2001-07-01

    A short-range polynomial interaction potential is introduced which has both a repulsive core and an attractive part. It is cut off smoothly such that its first and second derivatives vanish at the cutoff distance. The potential therefore enables efficient simulation studies of a model material that exhibits similarities to a full (but computationally expensive) classical Lennard-Jones system. Thermophysical properties of the model are calculated by (nonequilibrium) molecular dynamics computer simulations and compared with analytical results. Among the quantities studied is the pressure as a function of the density for various temperatures. Equations of state for the fluid and the solid are tested. The coexistence of gaseous, (metastable) liquid, and fcc solid phases is found for a range of temperatures. Bulk and shear moduli are computed. The response of the system to a shear deformation with a constant shear rate is analyzed. The liquid shows viscoelastic behavior that can be described with a Maxwell model. The solid behaves as an elastic medium up to a finite deformation and then undergoes a transition to plastic flow, which is stick-slip-like at small shear rates and continuous at higher ones. PMID:11461234

  11. Solids fluidizer-injector

    DOEpatents

    Bulicz, T.R.

    1990-04-17

    An apparatus and process are described for fluidizing solid particles by causing rotary motion of the solid particles in a fluidizing chamber by a plurality of rotating projections extending from a rotatable cylinder end wall interacting with a plurality of fixed projections extending from an opposite fixed end wall and passing the solid particles through a radial feed orifice open to the solids fluidizing chamber on one side and a solid particle utilization device on the other side. The apparatus and process are particularly suited for obtaining intermittent feeding with continual solids supply to the fluidizing chamber. The apparatus and process are suitable for injecting solid particles, such as coal, to an internal combustion engine. 3 figs.

  12. Characterization of solid state nuclear track detectors of the polyallyl-diglycol-carbonate (CR-39/PM-355) type for light charged particle spectroscopy

    SciTech Connect

    Malinowska, A. Jaskóła, M.; Korman, A.; Kuk, M.; Szydłowski, A.

    2014-12-15

    This paper presents a method which uses the characteristics of the etch pits induced in a polyallyl-diglycol-carbonate (PADC) detector of the CR-39/PM-355 type to estimate particle energy. This method is based on the data provided by a semiautomatic system that selects tracks according to two parameters, crater diameters, and mean gray level values. In this paper we used the results of the calibration measurements that were obtained in our laboratory in the period 2000–2014. Combining the information on the two parameters it is possible to determine unambiguously the incident projectile energy values. The paper presents the results of an attempt to estimate the energy resolution of the method when analyzing the tracks produced in the CR-39/PM-355 detector by energetic ions such as alpha particles, protons, and deuterons. We discuss the energy resolution of the measurement of light charged particle energy which is based on the parameters (crater diameter and mean gray level value) of tracks induced in solid state nuclear track detectors of the PADC type.

  13. Chemical compositions of solid particles present in the Greenland NEEM ice core over the last 110,000 years

    NASA Astrophysics Data System (ADS)

    Oyabu, Ikumi; Iizuka, Yoshinori; Fischer, Hubertus; Schüpbach, Simon; Gfeller, Gideon; Svensson, Anders; Fukui, Manabu; Steffensen, Jørgen Peder; Hansson, Margareta

    2015-09-01

    This study reports the chemical composition of particles present along Greenland's North Greenland Eemian Ice Drilling (NEEM) ice core, back to 110,000 years before present. Insoluble and soluble particles larger than 0.45 µm were extracted from the ice core by ice sublimation, and their chemical composition was analyzed using scanning electron microscope and energy dispersive X-ray spectroscopy and micro-Raman spectroscopy. We show that the dominant insoluble components are silicates, whereas NaCl, Na2SO4, CaSO4, and CaCO3 represent major soluble salts. For the first time, particles of CaMg(CO3)2 and Ca(NO3)2•4H2O are identified in a Greenland ice core. The chemical speciation of salts varies with past climatic conditions. Whereas the fraction of Na salts (NaCl + Na2SO4) exceeds that of Ca salts (CaSO4 + CaCO3) during the Holocene (0.6-11.7 kyr B.P.), the two fractions are similar during the Bølling-Allerød period (12.9-14.6 kyr B.P.). During cold climate such as over the Younger Dryas (12.0-12.6 kyr B.P.) and the Last Glacial Maximum (15.0-26.9 kyr B.P.), the fraction of Ca salts exceeds that of Na salts, showing that the most abundant ion generally controls the salt budget in each period. High-resolution analyses reveal changing particle compositions: those in Holocene ice show seasonal changes, and those in LGM ice show a difference between cloudy bands and clear layers, which again can be largely explained by the availability of ionic components in the atmospheric aerosol body of air masses reaching Greenland.

  14. High-temperature Processing of Solids through Solar Nebular Bow Shocks: 3D Radiation Hydrodynamics Simulations with Particles

    NASA Astrophysics Data System (ADS)

    Boley, A. C.; Morris, M. A.; Desch, S. J.

    2013-10-01

    A fundamental, unsolved problem in solar system formation is explaining the melting and crystallization of chondrules found in chondritic meteorites. Theoretical models of chondrule melting in nebular shocks have been shown to be consistent with many aspects of thermal histories inferred for chondrules from laboratory experiments; but, the mechanism driving these shocks is unknown. Planetesimals and planetary embryos on eccentric orbits can produce bow shocks as they move supersonically through the disk gas, and are one possible source of chondrule-melting shocks. We investigate chondrule formation in bow shocks around planetoids through three-dimensional radiation hydrodynamics simulations. A new radiation transport algorithm that combines elements of flux-limited diffusion and Monte Carlo methods is used to capture the complexity of radiative transport around bow shocks. An equation of state that includes the rotational, vibrational, and dissociation modes of H2 is also used. Solids are followed directly in the simulations and their thermal histories are recorded. Adiabatic expansion creates rapid cooling of the gas, and tail shocks behind the embryo can cause secondary heating events. Radiative transport is efficient, and bow shocks around planetoids can have luminosities ~few× 10-8 L ⊙. While barred and radial chondrule textures could be produced in the radiative shocks explored here, porphyritic chondrules may only be possible in the adiabatic limit. We present a series of predicted cooling curves that merit investigation in laboratory experiments to determine whether the solids produced by bow shocks are represented in the meteoritic record by chondrules or other solids.

  15. HIGH-TEMPERATURE PROCESSING OF SOLIDS THROUGH SOLAR NEBULAR BOW SHOCKS: 3D RADIATION HYDRODYNAMICS SIMULATIONS WITH PARTICLES

    SciTech Connect

    Boley, A. C.; Morris, M. A.; Desch, S. J.

    2013-10-20

    A fundamental, unsolved problem in solar system formation is explaining the melting and crystallization of chondrules found in chondritic meteorites. Theoretical models of chondrule melting in nebular shocks have been shown to be consistent with many aspects of thermal histories inferred for chondrules from laboratory experiments; but, the mechanism driving these shocks is unknown. Planetesimals and planetary embryos on eccentric orbits can produce bow shocks as they move supersonically through the disk gas, and are one possible source of chondrule-melting shocks. We investigate chondrule formation in bow shocks around planetoids through three-dimensional radiation hydrodynamics simulations. A new radiation transport algorithm that combines elements of flux-limited diffusion and Monte Carlo methods is used to capture the complexity of radiative transport around bow shocks. An equation of state that includes the rotational, vibrational, and dissociation modes of H{sub 2} is also used. Solids are followed directly in the simulations and their thermal histories are recorded. Adiabatic expansion creates rapid cooling of the gas, and tail shocks behind the embryo can cause secondary heating events. Radiative transport is efficient, and bow shocks around planetoids can have luminosities ∼few× 10{sup –8} L{sub ☉}. While barred and radial chondrule textures could be produced in the radiative shocks explored here, porphyritic chondrules may only be possible in the adiabatic limit. We present a series of predicted cooling curves that merit investigation in laboratory experiments to determine whether the solids produced by bow shocks are represented in the meteoritic record by chondrules or other solids.

  16. Development of a coupled discrete element (DEM)-smoothed particle hydrodynamics (SPH) simulation method for polyhedral particles

    NASA Astrophysics Data System (ADS)

    Nassauer, Benjamin; Liedke, Thomas; Kuna, Meinhard

    2016-03-01

    In the present paper, the direct coupling of a discrete element method (DEM) with polyhedral particles and smoothed particle hydrodynamics (SPH) is presented. The two simulation techniques are fully coupled in both ways through interaction forces between the solid DEM particles and the fluid SPH particles. Thus this simulation method provides the possibility to simulate the individual movement of polyhedral, sharp-edged particles as well as the flow field around these particles in fluid-saturated granular matter which occurs in many technical processes e.g. wire sawing, grinding or lapping. The coupled method is exemplified and validated by the simulation of a particle in a shear flow, which shows good agreement with analytical solutions.

  17. Measuring and modeling solids movement in a large, cold fluidized bed test facility. Fourth quarterly report, July 1, 1980-September 30, 1980

    SciTech Connect

    Fitzgerald, T. J.; Mrazek, R. V.; Crane, S. D.

    1980-09-01

    The principle of operation of the magnetic-particle, mass-flow measuring device was described in the first quarterly report. In addition, the results of a few preliminary tests which were carried out to show the feasibility of using this device were described in the third quarterly report. It was noted that the output signal from the device is proportional to velocity and that saturation of the material in the vicinity of the read coil had not yet been achieved. Thus, efforts during this quarter were concentrated upon two objectives - achieving saturation of the magnetic material in the vicinity of the road coil and establishing calibration procedures to be used with the device installed in a fluidized bed.

  18. Motions caused by the growth of Bacillus subtilis macrofibres in fluid medium result in new forms of movement of the multicellular structures over solid surfaces.

    PubMed

    Mendelson, N H; Sarlls, J E; Thwaites, J J

    2001-04-01

    Bacillus subtilis macrofibres, highly ordered multicellular structures, undergo twisting and writhing motions when they grow in fluid medium as a result of forces generated by the elongation of individual cells. Macrofibres are denser than the fluid medium in which they are cultured, consequently they settle to the bottom of the growth chamber and grow in contact with it. The ramifications of growth on plastic and glass surfaces were examined. Macrofibres were observed to rotate about a vertical axis near the centre of their length in a chiral-specific direction. Right-handed fibres rotated clockwise on plastic surfaces at approximately 4 degrees min(-1), left-handed structures of lower twist rotate anti-clockwise at about half that rate. Very large ball structures produced late in macrofibre formation perched on many small protruding fibres but rotated only when driven by large fibres attached to their periphery. Closer examination showed that fibres made contact with surfaces at only a few points along their length (between 1 and 6 on glass). The regions in contact with the surface changed periodically as a result of rotation of the fibre shaft caused by growth. Every time the weight of a fibre transferred from one contact point to another, each section of the fibre took a small step approximately proportional to its distance from the fibre mid-point. The net result was a rolling of each section over the surface so that the fibre rotation about a vertical axis was produced. Macrofibres also took large steps when part of the structure rose off the floor, swept through an arc in the fluid and then returned to the floor at a new location. The rate of movement during a large step, measured as the change of angle between the moving and stationary portions of the fibre, was 5 degrees s(-1). These observations reveal that the forces derived from helical growth that lead to macrofibre formation also cause characteristic macrofibre motion that differs from classical

  19. Ultrathin SmCo5 nanoflakes with high-coercivity prepared by solid particle (NaCl) and surfactant co-assisted ball milling.

    PubMed

    Zuo, Wen-Liang; Zhao, Xin; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2016-01-01

    The ultrathin SmCo5 nanoflakes with average thickness smaller than 50 nm are prepared by a novel method of solid particle (NaCl) and surfactant co-assisted ball milling. The as-prepared nanoflakes exhibit a narrower thickness distribution of 10-50 nm and high coercivity of 23 kOe. The possible formation mechanism of nanoflakes are proposed. Temperature dependence of demagnetization curves indicate that the magnetization reversal may be controlled by both nucleation and pinning. The results of X-ray powder diffraction and magnetic measurement for aligned SmCo5 nanoflakes resin composite indicate that the nanoflakes have a high texture degree. The ultrathin thickness and high coercivity are beneficial for preparing the high performance soft/hard coupling magnets and nanocomposite magnets. PMID:27174410

  20. Ultrathin SmCo5 nanoflakes with high-coercivity prepared by solid particle (NaCl) and surfactant co-assisted ball milling

    PubMed Central

    Zuo, Wen-Liang; Zhao, Xin; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2016-01-01

    The ultrathin SmCo5 nanoflakes with average thickness smaller than 50 nm are prepared by a novel method of solid particle (NaCl) and surfactant co-assisted ball milling. The as-prepared nanoflakes exhibit a narrower thickness distribution of 10–50 nm and high coercivity of 23 kOe. The possible formation mechanism of nanoflakes are proposed. Temperature dependence of demagnetization curves indicate that the magnetization reversal may be controlled by both nucleation and pinning. The results of X-ray powder diffraction and magnetic measurement for aligned SmCo5 nanoflakes resin composite indicate that the nanoflakes have a high texture degree. The ultrathin thickness and high coercivity are beneficial for preparing the high performance soft/hard coupling magnets and nanocomposite magnets. PMID:27174410

  1. Ultrathin SmCo5 nanoflakes with high-coercivity prepared by solid particle (NaCl) and surfactant co-assisted ball milling

    NASA Astrophysics Data System (ADS)

    Zuo, Wen-Liang; Zhao, Xin; Zhao, Tong-Yun; Hu, Feng-Xia; Sun, Ji-Rong; Shen, Bao-Gen

    2016-05-01

    The ultrathin SmCo5 nanoflakes with average thickness smaller than 50 nm are prepared by a novel method of solid particle (NaCl) and surfactant co-assisted ball milling. The as-prepared nanoflakes exhibit a narrower thickness distribution of 10–50 nm and high coercivity of 23 kOe. The possible formation mechanism of nanoflakes are proposed. Temperature dependence of demagnetization curves indicate that the magnetization reversal may be controlled by both nucleation and pinning. The results of X-ray powder diffraction and magnetic measurement for aligned SmCo5 nanoflakes resin composite indicate that the nanoflakes have a high texture degree. The ultrathin thickness and high coercivity are beneficial for preparing the high performance soft/hard coupling magnets and nanocomposite magnets.

  2. Eulerian multi-fluid models for the simulation of dynamics and coalescence of particles in solid propellant combustion

    NASA Astrophysics Data System (ADS)

    Doisneau, F.; Laurent, F.; Murrone, A.; Dupays, J.; Massot, M.

    2013-02-01

    The accurate simulation of polydisperse sprays undergoing coalescence in unsteady gaseous flows is a crucial issue. In solid rocket motors, the internal flow depends strongly on the alumina droplet size distribution, which spreads up with coalescence. Yet solving for unsteady two-phase flows with high accuracy on the droplet sizes is a challenge for both modeling and scientific computing. As an alternative to Lagrangian approaches, a wide range of Eulerian models have been recently developed to describe the disperse liquid phase at a lower cost, with an easier coupling to the gaseous phase and with massively parallel codes. Among these models, the multi-fluid model allows the detailed description of polydispersity and size/velocity correlations by separately solving fluids of size-sorted droplets, the so-called sections. The existing one size moment method, which describes the size distribution with one size moment per section, provides simple and fast resolution for coalescence. On the other hand, a two size moment method has been suggested to reduce the number of sections but it lacks an efficient coalescence resolution method. After introducing a new strategy for two size moment coalescence, the two methods are compared on various configurations in a research code and an industrial-oriented code, in order to conclude on computational accuracy and cost. Then the paper aims at describing the most efficient approach for multi-dimensional unsteady and eventually coalescing rocket chamber simulations. Its objective is threefold: first, to validate the two size moment method by comparing simulations to reference solutions and dedicated experimental measurements conducted at ONERA, second to study the efficiency and robustness of both methods, third, to draw some firm conclusions about the necessity to use the one size moment or two size moment method to simulate solid propellant alumina sprays. We finally perform the first simulations of coalescence in realistic 2D

  3. Development of a concentrating solar power system using fluidized-bed technology for thermal energy conversion and solid particles for thermal energy storage

    SciTech Connect

    Ma, Z.; Mehos, M.; Glatzmaier, G.; Sakadjian, B. B.

    2015-05-01

    Concentrating solar power (CSP) is an effective way to convert solar energy into electricity with an economic energy-storage capability for grid-scale, dispatchable renewable power generation. However, CSP plants need to reduce costs to be competitive with other power generation methods. Two ways to reduce CSP cost are to increase solar-to-electric efficiency by supporting a high-efficiency power conversion system, and to use low-cost materials in the system. The current nitrate-based molten-salt systems have limited potential for cost reduction and improved power-conversion efficiency with high operating temperatures. Even with significant improvements in operating performance, these systems face challenges in satisfying the cost and performance targets. This paper introduces a novel CSP system with high-temperature capability that can be integrated into a high-efficiency CSP plant and that meets the low-cost, high-performance CSP targets. Unlike a conventional salt-based CSP plant, this design uses gas/solid, two-phase flow as the heat-transfer fluid (HTF); separated solid particles as storage media; and stable, inexpensive materials for the high-temperature receiver and energy storage containment. We highlight the economic and performance benefits of this innovative CSP system design, which has thermal energy storage capability for base-load power generation.

  4. Development of a concentrating solar power system using fluidized-bed technology for thermal energy conversion and solid particles for thermal energy storage

    DOE PAGESBeta

    Ma, Z.; Mehos, M.; Glatzmaier, G.; Sakadjian, B. B.

    2015-05-01

    Concentrating solar power (CSP) is an effective way to convert solar energy into electricity with an economic energy-storage capability for grid-scale, dispatchable renewable power generation. However, CSP plants need to reduce costs to be competitive with other power generation methods. Two ways to reduce CSP cost are to increase solar-to-electric efficiency by supporting a high-efficiency power conversion system, and to use low-cost materials in the system. The current nitrate-based molten-salt systems have limited potential for cost reduction and improved power-conversion efficiency with high operating temperatures. Even with significant improvements in operating performance, these systems face challenges in satisfying the costmore » and performance targets. This paper introduces a novel CSP system with high-temperature capability that can be integrated into a high-efficiency CSP plant and that meets the low-cost, high-performance CSP targets. Unlike a conventional salt-based CSP plant, this design uses gas/solid, two-phase flow as the heat-transfer fluid (HTF); separated solid particles as storage media; and stable, inexpensive materials for the high-temperature receiver and energy storage containment. We highlight the economic and performance benefits of this innovative CSP system design, which has thermal energy storage capability for base-load power generation.« less

  5. Increasing dust-absorbing equipment operation efficiency using the automatic laser instrument for solid particle concentration measurement

    NASA Astrophysics Data System (ADS)

    Privalov, Vadim V.; Shemanin, Valery G.; Charty, Pavel V.

    2003-06-01

    The technological process of cement production, which side effect is dust generating and its exhausting to atmosphere, is not stopped as a rule when some faults were origin in dust-absorbing equipment (DAE). The analysis in reference one shows that longtime conducting of the technological process at DAE refusal or fault leads to its working efficiency reduction, which reveals itself in significant excess of nominal values of the dust output concentrations. The number of the most typical refusals and damages and algorithms of their searching were analyzed in work in reference 2 for the most wide-spread dust-absorber types: blanch and electrostatic filters. This work goal are the estimation of DAE working efficiency and choosing of the optimum way of its increasing with using of the automatic laser instrument for aerosol particles concentration measuring in the dust-air flows.

  6. Organic solids produced from simple C/H/O/N ices by charged particles - Applications to the outer solar system

    SciTech Connect

    Khare, B.N.; Thompson, W.R.; Chyba, C.F.; Sagan, C.; Arakawa, E.T.

    1989-01-01

    The effects of charged particle irradiation by cold plasma discharge on surfaces of H2O:CH4 clathrate with a 200:1 ratio and on ices composed of H2O and C2H6 or C2H2 are examined. The molecules studies are found in Comet Halley and are plausible constituents in icy outer solar system objects. The IR transmission spectra of four ice-tholin residues obtained in the laboratory are compared with spectra produced by irradiation of gases and ices containing simple hydrocarbons. The similarities between CH4 clathrate residue and Halley organic grains, and the surface transport or atmospheric replenishment activity on Triton and Pluto are discussed. 56 refs.

  7. ANFIS modeling for prediction of particle motions in fluid flows

    NASA Astrophysics Data System (ADS)

    Safdari, Arman; Kim, Kyung Chun

    2015-11-01

    Accurate dynamic analysis of parcel of solid particles driven in fluid flow system is of interest for many natural and industrial applications such as sedimentation process, study of cloud particles in atmosphere, etc. In this paper, numerical modeling of solid particles in incompressible flow using Eulerian-Lagrangian approach is carried out to investigate the dynamic behavior of particles in different flow conditions; channel and cavity flow. Although modern computers have been well developed, the high computational time and costs for this kind of problems are still demanded. The Lattice Boltzmann Method (LBM) is used to simulate fluid flows and combined with the Lagrangian approach to predict the motion of particles in the range of masses. Some particles are selected, and subjected to Adaptive-network-based fuzzy inference system (ANFIS) to predict the trajectory of moving solid particles. Using a hybrid learning procedure from computational particle movement, the ANFIS can construct an input-output mapping based on fuzzy if-then rules and stipulated computational fluid dynamics prediction pairs. The obtained results from ANFIS algorithm is validated and compared with the set of benchmark data provided based on point-like approach coupled with the LBM method.

  8. Thermal emission from large solid particles in the coma of comet C/2012 S1 (ISON) around perihelion

    NASA Astrophysics Data System (ADS)

    Keane, J.; Milam, S.; Coulson, I.; Gicquel, A.; Meech, K.; Yang, B.; Riesen, T.; Remijan, A.; Villanueva, G.; Corrinder, M.; Charnley, S.; Mumma, M.

    2014-07-01

    We report submillimeter dust-continuum observations for comet C/2012 S1 (ISON) obtained during the time period immediately before perihelion on 2013 November 28 (r = 0.0125 au). The variability and time resolution obtained in these images has revealed significant dust outbursts and have likely captured the onset of the final disruption event of comet ISON. The measured 450-μ m and 850-μ m submillimeter continuua are the strongest yet detected from a comet. Data were obtained with the SCUBA-2 submillimetre camera on the James Clerk Maxwell Telescope (JCMT) located at the 4000-m level of Mauna Kea, Hawaii during a week of scheduled day-time observing. Imaging is achieved simultaneously at wavelengths of 850 μ m and 450 μ m. Conditions necessary to obtain valuable results at 450 μ m occur relatively infrequently, and while atmospheric zenith opacities on the days involved were good (low), ranging between 0.08 (nepers at 225 GHz on the first day) and 0.05 (on the day of perihelion), the relatively low elevations of the observations (30--45 degrees), and consequent high line-of-sight opacities, limit the impact of the 450-μ m data. Each of the focal planes of SCUBA-2 is populated with 5000 bolometers, and provides an instantaneous Field of View of almost 10 arc minutes. In order to account effectively for the rapidly varying sky transmissions, the observational strategies adopted at JCMT involve scanning the telescope rapidly around the target in a daisy pattern, which produces fairly uniform coverage in exposure time of an area of diameter 3 arc minutes around the target centre. When comet ISON was first detected at 850 μ m, the 1-mm-sized dust particles were tightly bound to the comet nucleus until at least November 23. Three days later the dust was less tightly bound and became elongated and diffuse, spread out over as much as 120 arc seconds (80,000 km) in the anti-solar direction. Preliminary analyses of these observations suggest the detection of either a

  9. Improved solid aerosol generator

    DOEpatents

    Prescott, D.S.; Schober, R.K.; Beller, J.

    1988-07-19

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

  10. Solid aerosol generator

    DOEpatents

    Prescott, Donald S.; Schober, Robert K.; Beller, John

    1992-01-01

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates.

  11. Solid aerosol generator

    DOEpatents

    Prescott, D.S.; Schober, R.K.; Beller, J.

    1992-03-17

    An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration is disclosed. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

  12. Activation of the Solid Silica Layer of Aerosol-Based C/SiO₂ Particles for Preparation of Various Functional Multishelled Hollow Microspheres.

    PubMed

    Li, Xiangcun; Luo, Fan; He, Gaohong

    2015-05-12

    Double-shelled C/SiO2 hollow microspheres with an outer nanosheet-like silica shell and an inner carbon shell were reported. C/SiO2 aerosol particles were synthesized first by a one-step rapid aerosol process. Then the solid silica layer of the aerosol particles was dissolved and regrown on the carbon surface to obtain novel C/SiO2 double-shelled hollow microspheres. The new microspheres prepared by the facile approach possess high surface area and pore volume (226.3 m(2) g(-1), 0.51 cm(3) g(-1)) compared with the original aerosol particles (64.3 m(2) g(-1), 0.176 cm(3) g(-1)), providing its enhanced enzyme loading capacity. The nanosheet-like silica shell of the hollow microspheres favors the fixation of Au NPs (C/SiO2/Au) and prevents them from growing and migrating at 500 °C. Novel C/C and C/Au/C (C/Pt/C) hollow microspheres were also prepared based on the hollow nanostructure. C/C microspheres (482.0 m(2) g(-1), 0.92 cm(3) g(-1)) were ideal electrode materials. In particular, the Au NPs embedded into the two carbon layers (C/Au/C, 431.2 m(2) g(-1), 0.774 cm(3) g(-1)) show a high catalytic activity and extremely chemical stability even at 850 °C. Moreover, C/SiO2/Au, C/Au/C microspheres can be easily recycled and reused by an external magnetic field because of the presence of Fe3O4 species in the inner carbon shell. The synthetic route reported here is expected to simplify the fabrication process of double-shelled or yolk-shell microspheres, which usually entails multiple steps and a previously synthesized hard template. Such a capability can facilitate the preparation of various functional hollow microspheres by interfacial design.

  13. Helical Conformation in the CA-SP1 Junction of the Immature HIV-1 Lattice Determined from Solid-State NMR of Virus-like Particles.

    PubMed

    Bayro, Marvin J; Ganser-Pornillos, Barbie K; Zadrozny, Kaneil K; Yeager, Mark; Tycko, Robert

    2016-09-21

    Maturation of HIV-1 requires disassembly of the Gag polyprotein lattice, which lines the viral membrane in the immature state, and subsequent assembly of the mature capsid protein lattice, which encloses viral RNA in the mature state. Metastability of the immature lattice has been proposed to depend on the existence of a structurally ordered, α-helical segment spanning the junction between capsid (CA) and spacer peptide 1 (SP1) subunits of Gag, a segment that is dynamically disordered in the mature capsid lattice. We report solid state nuclear magnetic resonance (ssNMR) measurements on the immature lattice in noncrystalline, spherical virus-like particles (VLPs) derived from Gag. The ssNMR data provide definitive evidence for this critical α-helical segment in the VLPs. Differences in ssNMR chemical shifts and signal intensities between immature and mature lattice assemblies also support a major rearrangement of intermolecular interactions in the maturation process, consistent with recent models from electron cryomicroscopy and X-ray crystallography. PMID:27593947

  14. Helical Conformation in the CA-SP1 Junction of the Immature HIV-1 Lattice Determined from Solid-State NMR of Virus-like Particles.

    PubMed

    Bayro, Marvin J; Ganser-Pornillos, Barbie K; Zadrozny, Kaneil K; Yeager, Mark; Tycko, Robert

    2016-09-21

    Maturation of HIV-1 requires disassembly of the Gag polyprotein lattice, which lines the viral membrane in the immature state, and subsequent assembly of the mature capsid protein lattice, which encloses viral RNA in the mature state. Metastability of the immature lattice has been proposed to depend on the existence of a structurally ordered, α-helical segment spanning the junction between capsid (CA) and spacer peptide 1 (SP1) subunits of Gag, a segment that is dynamically disordered in the mature capsid lattice. We report solid state nuclear magnetic resonance (ssNMR) measurements on the immature lattice in noncrystalline, spherical virus-like particles (VLPs) derived from Gag. The ssNMR data provide definitive evidence for this critical α-helical segment in the VLPs. Differences in ssNMR chemical shifts and signal intensities between immature and mature lattice assemblies also support a major rearrangement of intermolecular interactions in the maturation process, consistent with recent models from electron cryomicroscopy and X-ray crystallography.

  15. Particle charge spectrometer

    NASA Technical Reports Server (NTRS)

    Fuerstenau, Stephen D. (Inventor)

    2004-01-01

    An airflow through a tube is used to guide a charged particle through the tube. A detector may be used to detect charge passing through the tube on the particle. The movement of the particle through the tube may be used to both detect its charge and size.

  16. Solid colloidal optical wavelength filter

    DOEpatents

    Alvarez, Joseph L.

    1992-01-01

    A solid colloidal optical wavelength filter includes a suspension of spheal particles dispersed in a coagulable medium such as a setting plastic. The filter is formed by suspending spherical particles in a coagulable medium; agitating the particles and coagulable medium to produce an emulsion of particles suspended in the coagulable medium; and allowing the coagulable medium and suspended emulsion of particles to cool.

  17. Teaching Creative Movement.

    ERIC Educational Resources Information Center

    Exiner, Johanna; Lloyd, Phyllis

    This guide to creative movement, relevant to all age groups, opens with a discussion of historical and present trends in movement and dance. Chapters treat (a) the body--body awareness, body activities, and relationships; (b) principles of movement--space, force, time, dynamics, and fluency; (c) topics within the sphere of movement, from the world…

  18. Movement disorders and sleep.

    PubMed

    Driver-Dunckley, Erika D; Adler, Charles H

    2012-11-01

    This article summarizes what is currently known about sleep disturbances in several movement disorders including Parkinson disease, essential tremor, parkinsonism, dystonia, Huntington disease, myoclonus, and ataxias. There is an association between movement disorders and sleep. In some cases the prevalence of sleep disorders is much higher in patients with movement disorder, such as rapid eye movement sleep behavior disorder in Parkinson disease. In other cases, sleep difficulties worsen the involuntary movements. In many cases the medications used to treat patients with movement disorder disturb sleep or cause daytime sleepiness. The importance of discussing sleep issues in patients with movement disorders cannot be underestimated.

  19. CFD modeling of PEPT results of particle motion trajectories in a pipe over an obstacle

    NASA Astrophysics Data System (ADS)

    Ghaffari, Maryam; Chang, Yu-Fen; Balakin, Boris; Hoffmann, Alex C.

    2012-09-01

    This paper aims to study the flow of a solid particle over a deposit in transport and processing equipment. Tracking particles and fluid elements moving through single- and multi-phase systems is very useful for studying numerous flow processes and identifying anomalies happening in the processes. Using Positron emission tomography (PET) and positron emission particle tracking (PEPT), that are relatively new techniques, it has become possible to visualize the movement of single particles in process equipment. The results from PEPT are here compared with particle-coupled Large Eddy Simulation numerical results. In the initial stages of the numerical modelling, results were validated using the PEPT experimental data in terms of its ability to correctly predict the flow and deposition of particles in a fluid flowing at a moderately low Reynolds number.

  20. Design of an alpha-particle counting system at a defined solid angle at Turkish atomic energy authority-Sarayköy nuclear research and training center (TAEK-SANAEM)

    NASA Astrophysics Data System (ADS)

    Seferinoğlu, Meryem; Yeltepe, Emin

    2015-12-01

    The design details of an alpha-particle counting set-up at a defined solid angle (ACS-DSA) constructed in Radionuclide Metrology Department at TAEK-SANAEM for use in the primary standardization of radioactive solutions and determination of nuclear decay data of alpha-particle emitters is presented. The counting system is designed such that the solid angle is very well-defined and directly traceable to the national standards. The design involves mechanical construction of different parts like the source chamber, various coaxial flanges, and circular diaphragms in front of the passivated implanted planar silicon (PIPS®) detector, distance tubes, a digital caliper and a sliding piston to allow for different measurement configurations. All geometric configurations are easily changeable and characterisable with high accuracy which facilitates the solid angle calculation. A mixed alpha source was counted to check performance of assembled ACS-DSA system and good energy resolution and low peak tailing in the alpha energy spectrum was observed for small diaphragm apertures and far source-to-detector geometries.

  1. Solid polymer electrolyte compositions

    DOEpatents

    Garbe, James E.; Atanasoski, Radoslav; Hamrock, Steven J.; Le, Dinh Ba

    2001-01-01

    An electrolyte composition is featured that includes a solid, ionically conductive polymer, organically modified oxide particles that include organic groups covalently bonded to the oxide particles, and an alkali metal salt. The electrolyte composition is free of lithiated zeolite. The invention also features cells that incorporate the electrolyte composition.

  2. Interaction between Nd-rich phase particles and liquid-solid interface in as-cast Ti-5Al-4Sn-2Zr-1Mo-0.25Si-1Nd titanium alloy

    SciTech Connect

    Li, G.P.; Li, D.; Liu, Y.Y.; Hu, Z.Q.

    1995-08-15

    The composition (wt%) of ingot fir this investigation is 86.75%Ti, 5%Al, 4%Sn, 2%Zr, 1%Mo, 0.25%Si, 1%Nd. The alloy was prepared by vacuum arc melting in the form of buttons of mass 500 kg, which was remelted three times repeatedly to obtain homogeneous composition. The Nd-rich phase particles in the as-cast Ti-55 alloy are about 1.2{approximately}11.07 {micro}m and uniformly distribute in the matrix. The shapes of the particles are mainly ellipsoids together with short needle-like and blocky morphologies. The calculated diameter of the Nd-rich phase particles is {approximately} 10 {micro}m, which is within the 1.2{approximately}11.07 {micro}m range of the particle diameter experimentally measured in the as-cast Ti-55 alloy. The practical interface velocity is three orders of magnitude greater than V c, and the Nd-rich phase particles in the as-cast Ti-55 alloy are trapped by the liquid-solid interface.

  3. Nondestructive characterization of municipal-solid-waste-contaminated surface soil by energy-dispersive X-ray fluorescence and low-Z (atomic number) particle electron probe X-ray microanalysis.

    PubMed

    Gupta, Dhrubajyoti; Ghosh, Rita; Mitra, Ajoy K; Roy, Subinit; Sarkar, Manoranjan; Chowdhury, Subhajit; Bhowmik, Asit; Mukhopadhyay, Ujjal; Maskey, Shila; Ro, Chul-Un

    2011-11-01

    The long-term environmental impact of municipal solid waste (MSW) landfilling is still under investigation due to the lack of detailed characterization studies. A MSW landfill site, popularly known as Dhapa, in the eastern fringe of the metropolis of Kolkata, India, is the subject of present study. A vast area of Dhapa, adjoining the current core MSW dump site and evolving from the raw MSW dumping in the past, is presently used for the cultivation of vegetables. The inorganic chemical characteristics of the MSW-contaminated Dhapa surface soil (covering a 2-km stretch of the area) along with a natural composite (geogenic) soil sample (from a small countryside farm), for comparison, were investigated using two complementary nondestructive analytical techniques, energy-dispersive X-ray fluorescence (EDXRF) for bulk analysis and low-Z (atomic number) particle electron probe X-ray microanalysis (low-Z particle EPMA) for single-particle analysis. The bulk concentrations of K, Rb, and Zr remain almost unchanged in all the soil samples. The Dhapa soil is found to be polluted with heavy metals such as Cu, Zn, and Pb (highly elevated) and Ti, Cr, Mn, Fe, Ni, and Sr (moderately elevated), compared to the natural countryside soil. These high bulk concentration levels of heavy metals were compared with the Ecological Soil Screening Levels for these elements (U.S. Environment Protection Agency) to assess the potential risk on the immediate biotic environment. Low-Z particle EPMA results showed that the aluminosilicate-containing particles were the most abundant, followed by SiO2, CaCO3-containing, and carbonaceous particles in the Dhapa samples, whereas in the countryside sample only aluminosilicate-containing and SiO2 particles were observed. The mineral particles encountered in the countryside sample are solely of geogenic origin, whereas those from the Dhapa samples seem to have evolved from a mixture of raw dumped MSW, urban dust, and other contributing factors such as wind

  4. Silage intake, rumination and pseudo-rumination activity in sheep studied by radiography and jaw movement recordings.

    PubMed

    Deswysen, A G; Ehrlein, H J

    1981-09-01

    1. The eating and ruminating activity of four rams given long-chopped silage ad lib. in two daily meals was studied by jaw movement recordings. The events of rumination and pseudo-rumination were observed by fluoroscopy and by cineradiography. 2. The rate of eating was highest at the beginning of the main meal and then declined gradually. 3. The silage intake level was low. 4. The swallowed silage did not accumulate at the cardiac region but was forced into the dorsal sac of the rumen by the contractions of the reticulum and cranial sac of the rumen. For regurgitation the solid particles had to return via the ventral and cranial sac of the rumen into the reticulum. 5. Liquid reticular contents with floating solid particles were aspirated into the oesophagus during the maximum of the regurgitation contraction of the reticulum. 6. The rumination activity during the day presented a high proportion of pseudo-rumination cycles whereas during the night the rumination became progressively normal. 7. Pseudo-rumination was caused by delayed return of the fibrous silage particles into the reticulum. Thus in pseudo-rumination the regurgitated material consisted predominantly of fluid containing only a small quantity of solid particles. 8. The results explain why long-chopped silage intake is associated with pseudo-rumination, a lower breakdown of particles and a waste of digestion time.

  5. Propagation of a spherical shock wave in mixture of non-ideal gas and small solid particles under the influence of gravitational field with conductive and radiative heat fluxes

    NASA Astrophysics Data System (ADS)

    Nath, G.

    2016-01-01

    Self-similar solutions are obtained for one-dimensional unsteady adiabatic flow behind a spherical shock wave propagating in a dusty gas with conductive and radiative heat fluxes under the influence of a gravitational field. The shock is assumed to be driven out by a moving piston and the dusty gas to be a mixture of non-ideal gas and small solid particles, in which solid particles are uniformly distributed. It is assumed that the equilibrium flow-conditions are maintained and variable energy input is continuously supplied by the piston. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient αR are assumed to vary with temperature and density. The medium is assumed to be under the influence of a gravitational field due to central mass ( bar{m} ) at the origin (Roche Model). It is assumed that the gravitational effect of the mixture itself can be neglected compared with the attraction of the central mass. The initial density of the ambient medium is taken to be always constant. The effects of the variation of the gravitational parameter and nonidealness of the gas in the mixture are investigated. Also, the effects of an increase in (i) the mass concentration of solid particles in the mixture and (ii) the ratio of the density of solid particles to the initial density of the gas on the flow variables are investigated. It is shown that due to an increase in the gravitational parameter the compressibility of the medium at any point in the flow-field behind the shock decreases and all other flow variables and the shock strength are increased. Further, it is found that the presence of gravitational field increases the compressibility of the medium, due to which it is compressed and therefore the distance between the piston and the shock surface is reduced. The shock waves in dusty gas under the influence of a

  6. Eye Movement Disorders

    MedlinePlus

    ... t work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder ... of the eyes, sometimes called "dancing eyes" Some eye movement disorders are present at birth. Others develop over ...

  7. Movement - unpredictable or jerky

    MedlinePlus

    ... Pregnancy (chorea gravidarum) Stroke Systemic lupus erythematosus Tardive dyskinesia (a condition that can be caused by medicines ... uncontrolled); Hyperkinetic movements References Jankovic J, Lang AE. Movement disorders. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta ...

  8. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  9. EXPERIMENTAL METHODS TO ESTIMATE ACCUMULATED SOLIDS IN NUCLEAR WASTE TANKS

    SciTech Connect

    Duignan, M.; Steeper, T.; Steimke, J.

    2012-12-10

    The Department of Energy has a large number of nuclear waste tanks. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles, e.g., plutonium containing, could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids and supernatant were charged to the test tank and rotating liquid jets were used to remove most of the solids. Then the volume and shape of the residual solids and the spatial concentration profiles for the surrogate for plutonium were measured. This paper discusses the overall test results, which indicated heavy solids only accumulate during the first few transfer cycles, along with the techniques and equipment designed and employed in the test. Those techniques include: Magnetic particle separator to remove stainless steel solids, the plutonium surrogate from a flowing stream; Magnetic wand used to manually remove stainless steel solids from samples and the tank heel; Photographs were used to determine the volume and shape of the solids mounds by developing a composite of topographical areas; Laser rangefinders to determine the volume and shape of the solids mounds; Core sampler to determine the stainless steel solids distribution within the solids mounds; Computer driven positioner that placed the laser rangefinders and the core sampler over solids mounds that accumulated on the bottom of a scaled staging tank in locations where jet velocities were low. These

  10. Bisphenol A in Solid Waste Materials, Leachate Water, and Air Particles from Norwegian Waste-Handling Facilities: Presence and Partitioning Behavior.

    PubMed

    Morin, Nicolas; Arp, Hans Peter H; Hale, Sarah E

    2015-07-01

    The plastic additive bisphenol A (BPA) is commonly found in landfill leachate at levels exceeding acute toxicity benchmarks. To gain insight into the mechanisms controlling BPA emissions from waste and waste-handling facilities, a comprehensive field and laboratory campaign was conducted to quantify BPA in solid waste materials (glass, combustibles, vehicle fluff, waste electric and electronic equipment (WEEE), plastics, fly ash, bottom ash, and digestate), leachate water, and atmospheric dust from Norwegian sorting, incineration, and landfill facilities. Solid waste concentrations varied from below 0.002 mg/kg (fly ash) to 188 ± 125 mg/kg (plastics). A novel passive sampling method was developed to, for the first time, establish a set of waste-water partition coefficients, KD,waste, for BPA, and to quantify differences between total and freely dissolved concentrations in waste-facility leachate. Log-normalized KD,waste (L/kg) values were similar for all solid waste materials (from 2.4 to 3.1), excluding glass and metals, indicating BPA is readily leachable. Leachate concentrations were similar for landfills and WEEE/vehicle sorting facilities (from 0.7 to 200 μg/L) and dominated by the freely dissolved fraction, not bound to (plastic) colloids (agreeing with measured KD,waste values). Dust concentrations ranged from 2.3 to 50.7 mg/kgdust. Incineration appears to be an effective way to reduce BPA concentrations in solid waste, dust, and leachate. PMID:26055751

  11. Bisphenol A in Solid Waste Materials, Leachate Water, and Air Particles from Norwegian Waste-Handling Facilities: Presence and Partitioning Behavior.

    PubMed

    Morin, Nicolas; Arp, Hans Peter H; Hale, Sarah E

    2015-07-01

    The plastic additive bisphenol A (BPA) is commonly found in landfill leachate at levels exceeding acute toxicity benchmarks. To gain insight into the mechanisms controlling BPA emissions from waste and waste-handling facilities, a comprehensive field and laboratory campaign was conducted to quantify BPA in solid waste materials (glass, combustibles, vehicle fluff, waste electric and electronic equipment (WEEE), plastics, fly ash, bottom ash, and digestate), leachate water, and atmospheric dust from Norwegian sorting, incineration, and landfill facilities. Solid waste concentrations varied from below 0.002 mg/kg (fly ash) to 188 ± 125 mg/kg (plastics). A novel passive sampling method was developed to, for the first time, establish a set of waste-water partition coefficients, KD,waste, for BPA, and to quantify differences between total and freely dissolved concentrations in waste-facility leachate. Log-normalized KD,waste (L/kg) values were similar for all solid waste materials (from 2.4 to 3.1), excluding glass and metals, indicating BPA is readily leachable. Leachate concentrations were similar for landfills and WEEE/vehicle sorting facilities (from 0.7 to 200 μg/L) and dominated by the freely dissolved fraction, not bound to (plastic) colloids (agreeing with measured KD,waste values). Dust concentrations ranged from 2.3 to 50.7 mg/kgdust. Incineration appears to be an effective way to reduce BPA concentrations in solid waste, dust, and leachate.

  12. Composite Solid Electrolyte For Lithium Cells

    NASA Technical Reports Server (NTRS)

    Peled, Emmanuel; Nagasubramanian, Ganesan; Halpert, Gerald; Attia, Alan I.

    1994-01-01

    Composite solid electrolyte material consists of very small particles, each coated with thin layer of Lil, bonded together with polymer electrolyte or other organic binder. Material offers significant advantages over other solid electrolytes in lithium cells and batteries. Features include high ionic conductivity and strength. Composite solid electrolyte expected to exhibit flexibility of polymeric electrolytes. Polymer in composite solid electrolyte serves two purposes: used as binder alone, conduction taking place only in AI2O3 particles coated with solid Lil; or used as both binder and polymeric electrolyte, providing ionic conductivity between solid particles that it binds together.

  13. Emerging Identity through Movement.

    ERIC Educational Resources Information Center

    Rowen, Betty

    Movement is one of the primary ways in which the young child finds out about his world. Experiences in movement help the young child to develop a healthy sense of identity. Through movement, children: (1) learn, as infants, to distinguish themselves from the outside world; (2) find out what they can do and how they can affect their environment;…

  14. Linking Literacy and Movement

    ERIC Educational Resources Information Center

    Pica, Rae

    2010-01-01

    There are many links between literacy and movement. Movement and language are both forms of communication and self-expression. Rhythm is an essential component of both language and movement. While people may think of rhythm primarily in musical terms, there is a rhythm to words and sentences as well. Individuals develop an internal rhythm when…

  15. [The "Participatory" Movement].

    PubMed

    Rossi, M J

    2001-01-01

    This study reports the trajectory of the Participatory Movement (MP), which was created in opposition to the policies carried out by the Brazilian Association of Nursing (ABEn). This article, written by the first president elected of the "participatory" movement, presents the principles of the movement, its organization, the struggle for leadership, and the work developed in the first administration.

  16. Functional titanium oxide nano-particles as electron lifetime, electrical conductance enhancer, and long-term performance booster in quasi-solid-state electrolyte for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Lue, Shingjiang Jessie; Wu, Yun-Ling; Tung, Yung-Liang; Shih, Chao-Ming; Wang, Yi-Chun; Li, Jun-Ruei

    2015-01-01

    This research investigates the design of a quasi-solid-state electrolyte for improving the photovoltaic efficiency and long-term performance stability of dye-sensitized solar cells (DSSCs). In this study, agarose gel and titanium oxide (TiO2) nano-particles are incorporated into an iodine/iodide electrolyte solution in a 1-methyl-2-pyrrolidinone (NMP)/3-methoxypropionitrile (MPN) solvent mixture to fabricate quasi-solid-state electrolytes for 2.0-cm2 DSSCs. The electrolyte also contains an ionic liquid, 1-methyl-3-propylimidazolium iodide, and a co-additive, 1-methylbenzimidazole. The negatively charged TiO2 nano-particles exhibit an anatase crystal structure. Without agarose and TiO2, the control cell's photovoltaic efficiency drops by more than 50% over 2400 h of aging due to a significant decrease in the short-circuit current. Incorporating 1% agarose into the electrolyte not only enhances the retention of the solvent but also maintains the short-circuit current. Furthermore, adding 0.5% TiO2 to 1% agarose electrolyte provides sufficient ion and electron transfer routes and improves the fill factor of the corresponding DSSC. The photoconversion efficiency of the agarose/TiO2-containing DSSC monotonically increases from an initial value of 5.08% to 6.48% within 2400 h. The improved cell efficiency is correlated to the longer electron lifetime in the DSSC, higher ion diffusivity, and the smaller electrical resistance of the electrolyte.

  17. On the existence and multiplicity of one-dimensional solid particle attractors in time-dependent Rayleigh-Bénard convection.

    PubMed

    Lappa, Marcello

    2013-03-01

    For the first time evidence is provided that one-dimensional objects formed by the accumulation of tracer particles can emerge in flows of thermogravitational nature (in the region of the space of parameters, in which the so-called OS (oscillatory solution) flow of the Busse balloon represents the dominant secondary mode of convection). Such structures appear as seemingly rigid filaments, rotating without changing their shape. The most interesting (heretofore unseen) feature of such a class of physical attractors is their variety. Indeed, distinct shapes are found for a fixed value of the Rayleigh number depending on parameters accounting for particle inertia and viscous drag. The fascinating "sea" of existing potential paths, their multiplicity and tortuosity are explained according to the granularity of the loci in the physical space where conditions for phase locking between the traveling thermofluid-dynamic disturbance and the "turnover time" of particles in the basic toroidal flow are satisfied. It is shown, in particular, how the observed wealth of geometric objects and related topological features can be linked to a general overarching attractor representing an intrinsic (particle-independent) property of the base velocity field.

  18. Ambient Tropospheric Particles

    EPA Science Inventory

    Atmospheric particulate matter (PM) is a complex mixture of solid and liquid particles suspended in ambient air (also known as the atmospheric aerosol). Ambient PM arises from a wide-range of sources and/or processes, and consists of particles of different shapes, sizes, and com...

  19. Fe3O4@Graphene Oxide@Ag Particles for Surface Magnet Solid-Phase Extraction Surface-Enhanced Raman Scattering (SMSPE-SERS): From Sample Pretreatment to Detection All-in-One.

    PubMed

    Liu, Zhigang; Wang, Yi; Deng, Rong; Yang, Liyuan; Yu, Shihua; Xu, Shuping; Xu, Weiqing

    2016-06-01

    A multifunctional magnetic graphene surface-enhanced Raman scattering (SERS) substrate was fabricated successfully by the layer-by-layer assembly of silver and graphene oxide (GO) nanoparticles (NPs) on the magnetic ferroferric oxide particles (Fe3O4@GO@Ag). This ternary particle possesses magnetic properties, SERS activity, and adsorption ability simultaneously. Owing to the multifunction of this Fe3O4@GO@Ag ternary complex, we put forward a new method called a surface magnetic solid-phase extraction (SMSPE) technique, for the SERS detections of pesticide residues on the fruit peels. SMSPE integrates many sample pretreatment procedures, such as surface extraction, separation sample, and detection, all-in-one. So this method shows great superiority in simplicity, rapidity, and high efficiency above other standard methods. The whole detection process can be finished within 20 min including the sample pretreatment and SERS detection. Owing to the high density of Ag NPs, the detection sensitivity is high enough that the lowest detectable concentrations are 0.48 and 40 ng/cm(2) for thiram and thiabendazole, which are much lower than the maximal residue limits in fruit prescribed by the U.S. Environmental Protection Agency. This multifunctional ternary particle and its corresponding analytical method have been proven to be applicable for practical samples and also valuable for other surface analysis. PMID:27191584

  20. Air agglomeration of hydrophobic particles

    SciTech Connect

    Drzymala, J.; Wheelock, T.D.

    1995-12-31

    The agglomeration of hydrophobic particles in an aqueous suspension was accomplished by introducing small amounts of air into the suspension while it was agitated vigorously. The extent of aggregation was proportional both to the air to solids ratio and to the hydrophobicity of the solids. For a given air/solids ratio, the extent of aggregation of different materials increased in the following order: graphite, gilsonite, coal coated with heptane, and Teflon. The structure of agglomerates produced from coarse Teflon particles differed noticeably from the structure of bubble-particle aggregates produced from smaller, less hydrophobic particles.

  1. Psychogenic Movement Disorders

    PubMed Central

    Morgante, Francesca; Edwards, Mark J.; Espay, Alberto J.

    2013-01-01

    Purpose of Review This review describes the main clinical features of psychogenic (functional) movement disorders and reports recent advances in diagnosis, pathophysiology, and treatment. Recent Findings The terminology and definition of patients with psychogenic movement disorders remain subjects of controversy; the term “functional” has been used more frequently in the literature in recent years regarding the neurobiological substrate underpinning these disorders. Correct diagnosis of psychogenic movement disorders should rely not on the exclusion of organic disorders or the sole presence of psychological factors but on the observation or elicitation of clinical features related to the specific movement disorder (ie, a positive or inclusionary rather than exclusionary diagnosis). Sudden onset, spontaneous remissions, and variability over time or during clinical examination are useful “red flags” suggestive of a psychogenic movement disorder. Imaging studies have demonstrated impaired connectivity between limbic and motor areas involved in movement programming and hypoactivity of a brain region that compares expected data with actual sensory data occurring during voluntary movement. Treatment of psychogenic movement disorders begins with ensuring the patient’s acceptance of the diagnosis during the initial debriefing and includes nonpharmacologic (cognitive-behavioral therapy, physiotherapy) and pharmacologic options. Summary Psychogenic movement disorders represent a challenging disorder for neurologists to diagnose and treat. Recent advances have increased understanding of the neurobiological mechanism of psychogenic movement disorders. Treatment with cognitive strategies and physical rehabilitation can benefit some patients. As short duration of disease correlates with better prognosis, early diagnosis and initiation of treatment are critical. PMID:24092294

  2. Online monitoring of particle mass flow rate in bottom spray fluid bed coating--development and application.

    PubMed

    Wang, Li Kun; Heng, Paul Wan Sia; Liew, Celine Valeria

    2010-08-16

    The primary purpose of this study is to develop a visiometric process analyzer for online monitoring of particle mass flow rate in the bottom spray fluid bed coating process. The secondary purpose is to investigate the influences of partition gap and air accelerator insert size on particle mass flow rate using the developed visiometric process analyzer. Particle movement in the region between the product chamber and partition column was captured using a high speed camera. Mean particle velocity and number of particles in the images were determined by particle image velocimetry and morphological image processing method respectively. Mass flow rate was calculated using particle velocity, number of particles in the images, particle density and size information. Particle velocity and number findings were validated using image tracking and manual particle counting techniques respectively. Validation experiments showed that the proposed method was accurate. Partition gap was found to influence particle mass flow rate by limiting the rate of solids flux into the partition column; the air accelerator insert was found to influence particle mass flow rate by a Venturi effect. Partition gap and air accelerator insert diameter needed to be adjusted accordingly in relation to the other variability sources and diameter of coating cores respectively. The potential, challenges and possible solutions of the proposed visiometric process analyzer were further discussed.

  3. [Sleep related movement disorders].

    PubMed

    Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi

    2015-06-01

    Sleep related movement disorders (SRMD) are characterized by simple, stereotyped movements occur during sleep, with the exception of restless legs syndrome (RLS). RLS has the following essential features; an urge to move the legs usually accompanied by uncomfortable sensation in the legs, improvement of symptoms after movement (non-stereotypical movements, such as walking and stretching, to reduce symptoms), and symptoms occur or worsen during periods of rest and in the evening and night. However, RLS is closely associated with periodic limb movement, which shows typical stererotyped limb movements. In the International Classification of Sleep Disorders, 3rd edition, sleep disturbances or daytime symptoms are prerequiste for a diagnosis of SRMD. We here review diagnosis and treatment of SRMD.

  4. Congenital mirror movements.

    PubMed Central

    Schott, G D; Wyke, M A

    1981-01-01

    In this report are described seven patients assessed clinically and neuropsychologically in whom mirror movements affecting predominantly the hands occurred as a congenital disorder. These mirror movements, representing a specific type of abnormal synkinesia, may arise as a hereditary condition, in the presence of a recognisable underlying neurological abnormality, and sporadically, and the seven patients provide more or less satisfactory examples of each of these three groups. Despite the apparent uniformity of the disorder, the heterogeneity and variability may be marked, examples in some of our patients including the pronounced increase in tone that developed with arm movement, and the capacity for modulation of the associated movement by alteration of neck position and bio-feedback. Various possible mechanisms are considered; these include impaired cerebral inhibition of unwanted movements, and functioning of abnormal motor pathways. Emphasis has been placed on the putative role of the direct, crossed corticomotoneurone pathways and on the unilateral and bilateral cerebral events that precede movement. PMID:7288446

  5. [Sleep related movement disorders].

    PubMed

    Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi

    2015-06-01

    Sleep related movement disorders (SRMD) are characterized by simple, stereotyped movements occur during sleep, with the exception of restless legs syndrome (RLS). RLS has the following essential features; an urge to move the legs usually accompanied by uncomfortable sensation in the legs, improvement of symptoms after movement (non-stereotypical movements, such as walking and stretching, to reduce symptoms), and symptoms occur or worsen during periods of rest and in the evening and night. However, RLS is closely associated with periodic limb movement, which shows typical stererotyped limb movements. In the International Classification of Sleep Disorders, 3rd edition, sleep disturbances or daytime symptoms are prerequiste for a diagnosis of SRMD. We here review diagnosis and treatment of SRMD. PMID:26065126

  6. Use of a small particle solid-core packing for improved efficiency and rapid measurement of sirolimus and everolimus by LC-MS/MS.

    PubMed

    Morgan, Phillip; Nwafor, Magnus; Tredger, Mike

    2016-06-01

    Measurement of whole blood sirolimus and everolimus is required in order to optimize patient treatment following solid organ transplant. Assay by LC-MS/MS is increasingly preferred; however efficient use of the instrument and short turnaround times are crucial. Use of a 1.6 µm solid-core packing HPLC column (Cortecs) gave significant increases in efficiency, sensitivity and throughput compared with an existing method, following simple protein precipitation of small-volume (20 μL) whole blood samples. Sirolimus, everolimus and the stable isotopic internal standard ((13) C2 D4 - everolimus) eluted at around 0.8 min, and total analytical run time was 2.2 min, saving almost 4 min per sample compared with an existing method. Within-assay imprecision (CV) was 3.3-8.5%, and between-assay imprecision was 2.2-10.8%. Retrospective assay of external quality assurance samples and comparison of patient samples assayed in parallel showed only small differences (between +6.8 and -1.9%) in results using the Cortecs column when compared with the existing method. No significant interferences or ion suppression were observed. Copyright © 2015 John Wiley & Sons, Ltd.

  7. A case study of real-time monitoring of solid-state phase transformations in acoustically levitated particles using near infrared and Raman spectroscopy.

    PubMed

    Rehder, Sönke; Wu, Jian X; Laackmann, Julian; Moritz, Hans-Ulrich; Rantanen, Jukka; Rades, Thomas; Leopold, Claudia S

    2013-01-23

    The objective of this study was to monitor the amorphous-to-crystalline solid-state phase transformation kinetics of the model drug ibuprofen with spectroscopic methods during acoustic levitation. Chemical and physical information was obtained by real-time near infrared (NIRS) and Raman spectroscopy measurements. The recrystallisation kinetic parameters (overall recrystallisation rate constant β and the time needed to reach 50% of the equilibrated level t(50)), were determined using a multivariate curve resolution approach. The acoustic levitation device coupled with non-invasive spectroscopy enabled monitoring of the recrystallisation process of the difficult-to-handle (adhesive) amorphous sample. The application of multivariate curve resolution enabled isolation of the underlying pure spectra, which corresponded well with the reference spectra of amorphous and crystalline ibuprofen. The recrystallisation kinetic parameters were estimated from the recrystallisation profiles. While the empirical recrystallisation rate constant determined by NIR and Raman spectroscopy were comparable, the lag time for recrystallisation was significantly lower with Raman spectroscopy as compared to NIRS. This observation was explained by the high energy density of the Raman laser beam, which might have led to local heating effects of the sample and thus reduced the recrystallisation onset time. It was concluded that acoustic levitation with NIR and Raman spectroscopy combined with multivariate curve resolution allowed direct determination of the recrystallisation kinetics of amorphous drugs and thus is a promising technique for monitoring solid-state phase transformations of adhesive small-sized samples during the early phase of drug development. PMID:23069619

  8. Making Solid Geometry Solid.

    ERIC Educational Resources Information Center

    Hartz, Viggo

    1981-01-01

    Allowing students to use a polystyrene cutter to fashion their own three-dimensional models is suggested as a means of allowing individuals to experience problems and develop ideas related to solid geometry. A list of ideas that can lead to mathematical discovery is provided. (MP)

  9. Solid phase extraction membrane

    DOEpatents

    Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

    2002-11-05

    A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

  10. Features of gravitational movement of loose material in an inclined pipe

    SciTech Connect

    Mukhin, I.I.; Petrov, V.N.

    1984-01-01

    This article reports on an investigation of the velocities of solid particle in zones of stabilized motion and outflow, the density of the flow, and the material discharge rate in free flow. Photography was used to determine the particle velocities and the trajectories of their motion. A small portion of sand that had been colored black (0.3-0.4 mm fraction) was added to a lightcolored sand. Photographs were taken of the steady-state motion of the fine-granular material (FGM) in a pipe with a diameter of 68 mm and a centrally located discharge opening. The basic physicomechanical properties of the materials investigated are listed. It is determined that the motion of particle entering the outflow zone in the region of the upper generatrix is retarded by the peripheral, relatively immobile material. The mean void fraction of the stream of sand in a vertical pipe is shown as a function of the velocity of sand movement. As the velocity of the material is increased, the void fraction increases slightly and then remains practically unchanged at 0.43. It is concluded that the observed features in the gravitational movement of loose material in inclined pipes can be utilized in the design of the inclined section of feed pipes and overflow pipes of process units such as catalytic crackers in which loose materials are transported pneumatically. Includes a table.

  11. The mathematics of movement

    USGS Publications Warehouse

    Johnson, D.H.

    1999-01-01

    Review of: Quantitative Analysis of Movement: Measuring and Modeling Population Redistribution in Animals and Plants. Peter Turchin. 1998. Sinauer Associates, Sunderland, MA. 306 pages. $38.95 (paper).

  12. Surface clogging process modeling of suspended solids during urban stormwater aquifer recharge.

    PubMed

    Wang, Zijia; Du, Xinqiang; Yang, Yuesuo; Ye, Xueyan

    2012-01-01

    Aquifer recharge, which uses urban stormwater, is an effective technique to control the negative effects of groundwater over-exploitation, while clogging problems in infiltration systems remain the key restricting factor in broadening its practice. Quantitative understanding of the clogging process is still very poor. A laboratory study was conducted to understand surface physical clogging processes, with the primary aim of developing a model for predicting suspended solid clogging processes before aquifer recharge projects start. The experiments investigated the clogging characteristics of different suspended solid sizes in recharge water by using a series of one-dimensional fine quartz sand columns. The results showed that the smaller the suspended particles in recharge water, the farther the distance of movement and the larger the scope of clogging in porous media. Clogging extents in fine sand were 1 cm, for suspended particle size ranging from 0.075 to 0.0385 mm, and 2 cm, for particles less than 0.0385 mm. In addition, clogging development occurred more rapidly for smaller suspended solid particles. It took 48, 42, and 36 hr respectively, for large-, medium-, and small-sized particles to reach pre-determined clogging standards. An empirical formula and iteration model for the surface clogging evolution process were derived. The verification results obtained from stormwater recharge into fine sand demonstrated that the model could reflect the real laws of the surface clogging process.

  13. Assessment of processes, facilities, and costs for alternative solid forms for immobilization of SRP defense waste. [Borosilicate; glass-lead; glass; concrete; ceramic; and coated particles

    SciTech Connect

    Dunson, J.B. Jr.; Eisenberg, A.M.; Schuyler, R.L. III; Haight, H.G. Jr.; Mello, V.E.; Gould, T.H. Jr.; Butler, J.L.; Pickett, J.B.

    1982-03-01

    A quantitative merit evaluation which assesses the relative difficulty of remote processing of Savannah River Plant high-level wastes for seven alternative waste forms is presented. The reference borosilicate glass process is rated as the simplest, followed by FUETAP concrete. The other processes evaluated in order of increasing complexity were: glass marbles in a lead matrix, high-silica glass, crystalline ceramic (Synroc-D and tailored ceramic), and coated ceramic particles. Cost appraisals are summarized for the borosilicate glass, high-silica glass, and ceramic waste form processing facilities.

  14. An experimental investigation on the effect of particle size on the thermal properties and void content of Solid Glass Microsphere filled epoxy Composites

    NASA Astrophysics Data System (ADS)

    Mishra, Debasmita; Satapathy, Alok

    2016-02-01

    This paper investigates about the thermal characterization of Solid glass micro-sphere (SGM) filled epoxy composites. SGMs of different sizes are embedded in epoxy resin to fabricate composites by hand-layup technique. The composites for various SGM content ranging from 0 to about 35 vol % are thus fabricated and the effective thermal conductivities (keff ) of the composites are estimated. The theoretical values are then compared with keff values obtained from the experiment. This study shows that the incorporation of SGm results in an improvement in thermal insulation capability of the polymer. Further, the influence of size and content of SGMs in the extent of reduction of keff was studied. Also, the effect of void content on improving insulation capability of the composites was analysed.

  15. Characterization of particle morphology of biochanin A molecularly imprinted polymers and their properties as a potential sorbent for solid-phase extraction.

    PubMed

    Chrzanowska, Anna M; Poliwoda, Anna; Wieczorek, Piotr P

    2015-04-01

    Molecularly imprinted polymers (MIPs) with biochanin A as a template were obtained using a bulk polymerization with non-covalent imprinting approach. The polymers were prepared in acetonitrile as porogen, using ethylene glycol dimethacrylate (EDMA) as cross-linking agent. The synthesis, with an application of 1',1'-azobis(cyclohexanecarbonitrile) (ACHN) as an initiator, has been performed thermally. During the synthesis process the effect of different functional monomers such as methacrylic acid (MAA), acrylamide (AA) and 4-vinylpyridine (4-VP) was investigated. The application of nitrogen sorption porosimetry, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) permitted the characterization and evaluation of synthesized polymers. The adsorption capacity of obtained MIPs was checked by using the binding testing. All synthesized polymers were evaluated as solid-phase extraction (SPE) sorbents for isolation and preconcentration of biochanin A and its analogues, daidzein and genistein. The MIPs exhibited higher affinity for biochanin A over competitive compounds. PMID:25687010

  16. In situ measurement technique for simultaneous detection of K, KCl, and KOH vapors released during combustion of solid biomass fuel in a single particle reactor.

    PubMed

    Sorvajärvi, Tapio; DeMartini, Nikolai; Rossi, Jussi; Toivonen, Juha

    2014-01-01

    A quantitative and simultaneous measurement of K, KCl, and KOH vapors from a burning fuel sample combusted in a single particle reactor was performed using collinear photofragmentation and atomic absorption spectroscopy (CPFAAS) with a time resolution of 0.2 s. The previously presented CPFAAS technique was extended in this work to cover two consecutive fragmentation pulses for the photofragmentation of KCl and KOH. The spectral overlapping of the fragmentation spectra of KCl and KOH is discussed, and a linear equation system for the correction of the spectral interference is introduced. The detection limits for KCl, KOH, and K with the presented measurement arrangement and with 1 cm sample length were 0.5, 0.1, and 0.001 parts per million, respectively. The experimental setup was applied to analyze K, KCl, and KOH release from 10 mg spruce bark samples combusted at the temperatures of 850, 950, and 1050 °C with 10% of O2. The combustion experiments provided data on the form of K vapors and their release during different combustion phases and at different temperatures. The measured release histories agreed with earlier studies of K release. The simultaneous direct measurement of atomic K, KCl, and KOH will help in the impact of both the form of K in the biomass and fuel variables, such as particle size, on the release of K from biomass fuels.

  17. Randomness Of Amoeba Movements

    NASA Astrophysics Data System (ADS)

    Hashiguchi, S.; Khadijah, Siti; Kuwajima, T.; Ohki, M.; Tacano, M.; Sikula, J.

    2005-11-01

    Movements of amoebas were automatically traced using the difference between two successive frames of the microscopic movie. It was observed that the movements were almost random in that the directions and the magnitudes of the successive two steps are not correlated, and that the distance from the origin was proportional to the square root of the step number.

  18. The Human Potential Movement.

    ERIC Educational Resources Information Center

    Tamashiro, Roy T.

    The advent of the human potential movement has generated the expectation that educators unleash the intellectual, emotional, physical, and spiritual talents of students. This movement is characterized by its focus on (1) the person as a total being, (2) the needs and concerns of students, (3) phenomenology, (4) personal values and goals, and (5)…

  19. [Dance/Movement Therapy.

    ERIC Educational Resources Information Center

    Fenichel, Emily, Ed.

    1994-01-01

    This newsletter theme issue focuses on dance, play, and movement therapy for infants and toddlers with disabilities. Individual articles are: "Join My Dance: The Unique Movement Style of Each Infant and Toddler Can Invite Communication, Expression and Intervention" (Suzi Tortora); "Dynamic Play Therapy: An Integrated Expressive Arts Approach to…

  20. 85 Engaging Movement Activities.

    ERIC Educational Resources Information Center

    Weikart, Phyllis S.; Carlton, Elizabeth B.

    This book presents activities to keep K-6 students moving in a variety of ways as they learn. The movement experiences are planned around key curriculum concepts in movement and music as well as in academic curriculum areas. The experiences develop students' basic timing, language abilities, vocabulary, concentration, planning skills, and…

  1. National CARES Mentoring Movement

    ERIC Educational Resources Information Center

    Mitchell, Martin L.

    2013-01-01

    Harsh and cruel experiences have led many of our young to believe that they are alone in the world and that no one cares. In this article, Martin L Mitchell introduces us to the "National CARES Mentoring Movement" founded by Susan L.Taylor. This movement provides young people with role models who help shape their positive development.…

  2. Method for using magnetic particles in droplet microfluidics

    NASA Technical Reports Server (NTRS)

    Shah, Gaurav Jitendra (Inventor); Kim, Chang-Jin (Inventor)

    2012-01-01

    Methods of utilizing magnetic particles or beads (MBs) in droplet-based (or digital) microfluidics are disclosed. The methods may be used in enrichment or separation processes. A first method employs the droplet meniscus to assist in the magnetic collection and positioning of MBs during droplet microfluidic operations. The sweeping movement of the meniscus lifts the MBs off the solid surface and frees them from various surface forces acting on the MBs. A second method uses chemical additives to reduce the adhesion of MBs to surfaces. Both methods allow the MBs on a solid surface to be effectively moved by magnetic force. Droplets may be driven by various methods or techniques including, for example, electrowetting, electrostatic, electromechanical, electrophoretic, dielectrophoretic, electroosmotic, thermocapillary, surface acoustic, and pressure.

  3. The Formation of Solid Particles from their Gas-Phase Molecular Precursors in Cosmic Environments with NASA Ames' COSmIC Facility

    NASA Technical Reports Server (NTRS)

    Salama, Farid

    2014-01-01

    We present and discuss the unique characteristics and capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to generate, process and analyze interstellar, circumstellar and planetary analogs in the laboratory. COSmIC stands for Cosmic Simulation Chamber and is dedicated to the study of molecules and ions under the low temperature and high vacuum conditions that are required to simulate interstellar, circumstellar and planetary physical environments in space. COSmIC integrates a variety of state-of-the-art instruments that allow forming, processing and monitoring simulated space conditions for planetary, circumstellar and interstellar materials in the laboratory. COSmIC is composed of a Pulsed Discharge Nozzle (PDN) expansion that generates a free jet supersonic expansion coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a Cavity Ring Down Spectroscopy (CRDS) system for photonic detection and a Reflectron Time-Of-Flight Mass Spectrometer (ReTOF-MS) for mass detection. Recent, unique, laboratory astrophysics results that were obtained using the capabilities of COSmIC will be discussed, in particular the progress that have been achieved in monitoring in the laboratory the formation of solid gains from their gas-phase molecular precursors in environments as varied as stellar/circumstellar outflow and planetary atmospheres. Plans for future, next generation, laboratory experiments on cosmic molecules and grains in the growing field of laboratory astrophysics will also be addressed as well as the implications of these studies for current and upcoming space missions.

  4. Scalability study of solid xenon

    SciTech Connect

    Yoo, J.; Cease, H.; Jaskierny, W. F.; Markley, D.; Pahlka, R. B.; Balakishiyeva, D.; Saab, T.; Filipenko, M.

    2015-04-01

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified {\\it Bridgeman's technique} reproduces a large scale optically transparent solid xenon.

  5. Scalability study of solid xenon

    NASA Astrophysics Data System (ADS)

    Yoo, J.; Cease, H.; Jaskierny, W. F.; Markley, D.; Pahlka, R. B.; Balakishiyeva, D.; Saab, T.; Filipenko, M.

    2015-04-01

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified Bridgeman's technique reproduces a large scale optically transparent solid xenon.

  6. Enhanced methane steam reforming activity and electrochemical performance of Ni0.9Fe0.1-supported solid oxide fuel cells with infiltrated Ni-TiO2 particles

    PubMed Central

    Li, Kai; Jia, Lichao; Wang, Xin; Pu, Jian; Chi, Bo; Li, Jian

    2016-01-01

    Ni0.9Fe0.1 alloy-supported solid oxide fuel cells with NiTiO3 (NTO) infiltrated into the cell support from 0 to 4 wt.% are prepared and investigated for CH4 steam reforming activity and electrochemical performance. The infiltrated NiTiO3 is reduced to TiO2-supported Ni particles in H2 at 650 °C. The reforming activity of the Ni0.9Fe0.1-support is increased by the presence of the TiO2-supported Ni particles; 3 wt.% is the optimal value of the added NTO, corresponding to the highest reforming activity, resistance to carbon deposition and electrochemical performance of the cell. Fueled wet CH4 at 100 mL min−1, the cell with 3 wt.% of NTO demonstrates a peak power density of 1.20 W cm−2 and a high limiting current density of 2.83 A cm−2 at 650 °C. It performs steadily for 96 h at 0.4 A cm−2 without the presence of deposited carbon in the Ni0.9Fe0.1-support and functional anode. Five polarization processes are identified by deconvoluting and data-fitting the electrochemical impedance spectra of the cells under the testing conditions; and the addition of TiO2-supported Ni particles into the Ni0.9Fe0.1-support reduces the polarization resistance of the processes ascribed to CH4 steam reforming and gas diffusion in the Ni0.9Fe0.1-support and functional anode. PMID:27775092

  7. Auxin and chloroplast movements.

    PubMed

    Eckstein, Aleksandra; Krzeszowiec, Weronika; Waligórski, Piotr; Gabryś, Halina

    2016-03-01

    Auxin is involved in a wide spectrum of physiological processes in plants, including responses controlled by the blue light photoreceptors phototropins: phototropic bending and stomatal movement. However, the role of auxin in phototropin-mediated chloroplast movements has never been studied. To address this question we searched for potential interactions between auxin and the chloroplast movement signaling pathway using different experimental approaches and two model plants, Arabidopsis thaliana and Nicotiana tabacum. We observed that the disturbance of auxin homeostasis by shoot decapitation caused a decrease in chloroplast movement parameters, which could be rescued by exogenous auxin application. In several cases, the impairment of polar auxin transport, by chemical inhibitors or in auxin carrier mutants, had a similar negative effect on chloroplast movements. This inhibition was not correlated with changes in auxin levels. Chloroplast relocations were also affected by the antiauxin p-chlorophenoxyisobutyric acid and mutations in genes encoding some of the elements of the SCF(TIR1)-Aux/IAA auxin receptor complex. The observed changes in chloroplast movement parameters are not prominent, which points to a modulatory role of auxin in this process. Taken together, the obtained results suggest that auxin acts indirectly to regulate chloroplast movements, presumably by regulating gene expression via the SCF(TIR1)-Aux/IAA-ARF pathway. Auxin does not seem to be involved in controlling the expression of phototropins.

  8. Particle Deposition in Drying Drops of Colloidal Suspensions Containing Different Surfactants

    NASA Astrophysics Data System (ADS)

    Still, Tim; Yunker, Peter J.; Yodh, A. G.

    2012-02-01

    When a drop of water containing small solid particles dries, most of the solid material is deposited in a ring-shape stain after evaporation (the so-called coffee ring), driven by initial contact line pinning and a subsequent outward-flow. The fluid dynamics and, hence, the deposition mechanism in such suspensions can be dramatically changed when surfactants are introduced into the system. In a colloidal model-system, the ionic sodium dodecyl sulfate (SDS) produces a concentration-driven Marangoni flow counteracting the outward-flow of the coffee ring effect. SDS locally concentrates at the air/water interface next to the contact line, leading to a reduced local surface tension. Thus, a circulating flow (`Marangoni eddy') is introduced that prevents particles from deposition. This flow is visualized by the movements of the dragged particles using video microscopy. Other surfactants can influence this highly non-equilibrium systems in completely other ways. E.g., the non-ionic Polaxamer block-copolymer surfactants lead to a uniform particle deposition, which we explain by hydrophilization of the colloidal particles. Controlling the solid deposition in drying drops is of major importance for many technical applications.

  9. Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

    USGS Publications Warehouse

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

    2014-01-01

    Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines

  10. Development of All-Solid-State Sensors for Measurement of Nitric Oxide and Ammonia Concentrations by Optical Absorption in Particle-Laden Combusion Exhaust Streams

    SciTech Connect

    Jerald A. Caton; Kalyan Annamalai

    2003-09-24

    An all-solid-state continuous-wave (cw) laser system for ultraviolet absorption measurements of the nitric oxide (NO) molecule has been developed and demonstrated. For the NO sensor, 250 nW of tunable cw ultraviolet radiation is produced by sum-frequency-mixing of 532-nm radiation from a diode-pumped Nd:YAG laser and tunable 395-nm radiation from an external cavity diode laser (ECDL). The sum-frequency-mixing process occurs in a beta-barium borate crystal. The nitric oxide absorption measurements are performed by tuning the ECDL and scanning the sum-frequency-mixed radiation over strong nitric oxide absorption lines near 226 nm. The nitric oxide sensor has been used for measurements in the exhaust of a coal-fired laboratory combustion facility. The Texas A&M University boiler burner facility is a 30 kW (100,000 Btu/hr) downward-fired furnace with a steel shell encasing ceramic insulation. Measurements of nitric oxide concentration in the exhaust stream were performed after modification of the facility for laser based NOx diagnostics. The diode-laser-based sensor measurements showed good agreement with the results from physical probe sampling of the combustion exhaust. The diode-laser-based ultraviolet absorption measurements were successful even when the beam was severely attenuated by particulate in the exhaust stream and window fouling. Single-laser-sweep measurements were demonstrated with an effective time resolution of 100 msec, limited at this time by the scan rate of our mechanically tuned ECDL system. Future planned modifications will lead to even faster response times at sensitivity levels at or below 1 ppm.

  11. Systematic Investigation of Binders for Silicon Anodes: Interactions of Binder with Silicon Particles and Electrolytes and Effects of Binders on Solid Electrolyte Interphase Formation.

    PubMed

    Nguyen, Cao Cuong; Yoon, Taeho; Seo, Daniel M; Guduru, Pradeep; Lucht, Brett L

    2016-05-18

    The effects of different binders, polyvinylidene difluoride (PVdF), poly(acrylic acid) (PAA), sodium carboxymethyl cellulose (CMC), and cross-linked PAA-CMC (c-PAA-CMC), on the cycling performance and solid electrolyte interphase (SEI) formation on silicon nanoparticle electrodes have been investigated. Electrodes composed of Si-PAA, Si-CMC, and Si-PAA-CMC exhibit a specific capacity ≥3000 mAh/g after 20 cycles while Si-PVdF electrodes have a rapid capacity fade to 1000 mAh/g after just 10 cycles. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) reveal that PAA and CMC react with the surface of the Si nanoparticles during electrode fabrication. The fresh Si-CMC electrode has a thicker surface coating of SiOx than Si-PAA and Si-PAA-CMC electrodes, due to the formation of thicker SiOx during electrode preparation, which leads to lower cyclability. The carboxylic acid functional groups of the PAA binder are reactive toward the electrolyte, causing the decomposition of LiPF6 and dissolution of SiOx during the electrode wetting process. The PAA and CMC binder surface films are then electrochemically reduced during the first cycle to form a protective layer on Si. This layer effectively suppresses the decomposition of carbonate solvents during cycling resulting in a thin SEI. On the contrary, the Si-PVDF electrode has poor cycling performance and continuous reduction of carbonate solvents is observed resulting in the generation of a thicker SEI. Interestingly, the Lewis basic -CO2Na of CMC was found to scavenge HF in electrolyte. PMID:27135935

  12. High-resolution solid-state NMR in liquids. 2. sup 27 Al NMR study of AlF sub 3 ultrafine particles

    SciTech Connect

    Satoh, Naoki ); Kimura, Keisaku )

    1990-06-06

    High-resolution {sup 27}Al nuclear magnetic resonance spectra of AlF{sub 3} ultrafine particles (UFPs) were obtained by means of motional narrowing caused by Brownian motion of UFPs in a liquid phase. The NMR observed spectra can be resolved in five signals at 10, {minus}5, {minus}8, {minus}12, and {minus}16 ppm with respect to an Al{sup 3+}(H{sub 2}O){sub 6} standard. The UFPs were fractionated according to their sizes by using an ultrafiltration technique. From the NMR measurements of fractionated colloidal solutions, the five peaks were classified into three groups by their origins, viz. the peak at {minus}16 ppm is from larger UFPs (diameter D; 9 nm), those at {minus}5, {minus}8, and {minus}12 ppm from smaller UFPs (1 < D < 3 nm), while that at 10 ppm from free ions. Line widths of the larger and smaller UFPs were about 10 and 4 ppm (i.e., 1 and 0.4 kHz), respectively.

  13. Student Misapplication of a Gas-Like Model to Explain Particle Movement in Heated Solids: Implications for Curriculum and Instruction towards Students' Creation and Revision of Accurate Explanatory Models

    ERIC Educational Resources Information Center

    Bouwma-Gearhart, Jana; Stewart, James; Brown, Keffrelyn

    2009-01-01

    Understanding the particulate nature of matter (PNM) is vital for participating in many areas of science. We assessed 11 students' atomic/molecular-level explanations of real-world phenomena after their participation in a modelling-based PNM unit. All 11 students offered a scientifically acceptable model regarding atomic/molecular behaviour in…

  14. A New Mechanism for Ozonolysis of Unsaturated Organics on Solids: Phosphocholines on NaCl as A Model for Sea Salt particles

    SciTech Connect

    Karagulian, Federico; Lea, Alan S; Dilbeck, Christopher W; Finlayson-Pitts, Barbara J

    2008-01-28

    The ozonolysis of an approximately one monolayer film of 1-oleoyl-2-palmitoyl-sn-glycero-3-phosphocholine (OPPC) on NaCl was followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) at 23 °C. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and AUGER electron spectroscopy were used as complementary analytical techniques. Ozone concentrations ranged from 1.7 x 1012 to 7.0 x 1013 molecules cm-3 (70 ppb to 2.5 ppm). Upon exposure to O3, there was a loss of C=C accompanied by the formation of a strong band at ~1110 cm-1 due to the formation of a stable secondary ozonide (1,3,4-trioxolane, SOZ). The yield of the SOZ was lower when the reaction was carried out in the presence of water vapor at concentrations corresponding to relative humidities between 2 and 25 %. The dependencies of the rate of SOZ formation on the concentrations of ozone and water vapor are consistent with the initial formation of a primary ozonide (1,2,3-trioxolane, POZ) that can react with O3 or H2O in competition with its thermal decomposition to a Criegee intermediate and aldehyde. This interpretation is also consistent with the measured dependence of the SOZ yield on the ozone concentration. Estimates were obtained for the rate constants for the POZ thermal decomposition and for its reactions with O3 and H2O, as well as for the initial reaction of O3 with OPPC. The SOZ decomposed upon photolysis at x > 300 nm, generating aldehydes, carboxylic acids and anhydrides. These studies show that the primary ozonide has a sufficiently long lifetime when formed on a solid substrate that direct reactions with O3 and H2O can compete with its thermal decomposition. In dry polluted atmospheres, ozone-alkene reactions may lead in part to the formation of stable secondary ozonides whose chemistry, photochemistry and toxicity should be taken into account in models of such regions.

  15. Movement coordination during conversation.

    PubMed

    Latif, Nida; Barbosa, Adriano V; Vatikiotis-Bateson, Eric; Vatiokiotis-Bateson, Eric; Castelhano, Monica S; Munhall, K G

    2014-01-01

    Behavioral coordination and synchrony contribute to a common biological mechanism that maintains communication, cooperation and bonding within many social species, such as primates and birds. Similarly, human language and social systems may also be attuned to coordination to facilitate communication and the formation of relationships. Gross similarities in movement patterns and convergence in the acoustic properties of speech have already been demonstrated between interacting individuals. In the present studies, we investigated how coordinated movements contribute to observers' perception of affiliation (friends vs. strangers) between two conversing individuals. We used novel computational methods to quantify motor coordination and demonstrated that individuals familiar with each other coordinated their movements more frequently. Observers used coordination to judge affiliation between conversing pairs but only when the perceptual stimuli were restricted to head and face regions. These results suggest that observed movement coordination in humans might contribute to perceptual decisions based on availability of information to perceivers. PMID:25119189

  16. Movement Coordination during Conversation

    PubMed Central

    Latif, Nida; Barbosa, Adriano V.; Vatiokiotis-Bateson, Eric; Castelhano, Monica S.; Munhall, K. G.

    2014-01-01

    Behavioral coordination and synchrony contribute to a common biological mechanism that maintains communication, cooperation and bonding within many social species, such as primates and birds. Similarly, human language and social systems may also be attuned to coordination to facilitate communication and the formation of relationships. Gross similarities in movement patterns and convergence in the acoustic properties of speech have already been demonstrated between interacting individuals. In the present studies, we investigated how coordinated movements contribute to observers’ perception of affiliation (friends vs. strangers) between two conversing individuals. We used novel computational methods to quantify motor coordination and demonstrated that individuals familiar with each other coordinated their movements more frequently. Observers used coordination to judge affiliation between conversing pairs but only when the perceptual stimuli were restricted to head and face regions. These results suggest that observed movement coordination in humans might contribute to perceptual decisions based on availability of information to perceivers. PMID:25119189

  17. Photocatalytic/Magnetic Composite Particles

    NASA Technical Reports Server (NTRS)

    Wu, Chang-Yu; Goswami, Yogi; Garretson, Charles; Andino, Jean; Mazyck, David

    2007-01-01

    Photocatalytic/magnetic composite particles have been invented as improved means of exploiting established methods of photocatalysis for removal of chemical and biological pollutants from air and water. The photocatalytic components of the composite particles are formulated for high levels of photocatalytic activity, while the magnetic components make it possible to control the movements of the particles through the application of magnetic fields. The combination of photocatalytic and magnetic properties can be exploited in designing improved air- and water treatment reactors.

  18. Fluid movement and creativity.

    PubMed

    Slepian, Michael L; Ambady, Nalini

    2012-11-01

    Cognitive scientists describe creativity as fluid thought. Drawing from findings on gesture and embodied cognition, we hypothesized that the physical experience of fluidity, relative to nonfluidity, would lead to more fluid, creative thought. Across 3 experiments, fluid arm movement led to enhanced creativity in 3 domains: creative generation, cognitive flexibility, and remote associations. Alternative mechanisms such as enhanced mood and motivation were also examined. These results suggest that creativity can be influenced by certain types of physical movement.

  19. Cooperative particle motion in complex (dusty) plasmas

    NASA Astrophysics Data System (ADS)

    Zhdanov, Sergey; Morfill, Gregor

    2014-05-01

    Strongly coupled complex (dusty) plasmas give us a unique opportunity to go beyond the limits of continuous media and study various generic processes occurring in liquids or solids at the kinetic level. A particularly interesting and challenging topic is to study dynamic cooperativity at local and intermediate scales. As an important element of self-organization, cooperative particle motion is present in many physical, astrophysical and biological systems. As a rule, cooperative dynamics, bringing to life 'abnormal' effects like enhanced diffusion, self-dragging, or self-propelling of particles, hold aspects of 'strange' kinetics. The synergy effects are also important. Such kind of cooperative behavior was evidenced for string-like formations of colloidal rods, dynamics of mono- and di-vacancies in 2d colloidal crystals. Externally manipulated 'dust molecules' and self-assembled strings in driven 3d particle clusters were other noticeable examples. There is a certain advantage to experiment with complex plasmas merely because these systems are easy to manipulate in a controllable way. We report on the first direct observation of microparticle cooperative movements occurring under natural conditions in a 2d complex plasma.

  20. Solid-solid phase transitions via melting in metals.

    PubMed

    Pogatscher, S; Leutenegger, D; Schawe, J E K; Uggowitzer, P J; Löffler, J F

    2016-04-22

    Observing solid-solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid-solid transition via the formation of a metastable liquid in a 'real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory.

  1. Solid-solid phase transitions via melting in metals

    NASA Astrophysics Data System (ADS)

    Pogatscher, S.; Leutenegger, D.; Schawe, J. E. K.; Uggowitzer, P. J.; Löffler, J. F.

    2016-04-01

    Observing solid-solid phase transitions in-situ with sufficient temporal and spatial resolution is a great challenge, and is often only possible via computer simulations or in model systems. Recently, a study of polymeric colloidal particles, where the particles mimic atoms, revealed an intermediate liquid state in the transition from one solid to another. While not yet observed there, this finding suggests that such phenomena may also occur in metals and alloys. Here we present experimental evidence for a solid-solid transition via the formation of a metastable liquid in a `real' atomic system. We observe this transition in a bulk glass-forming metallic system in-situ using fast differential scanning calorimetry. We investigate the corresponding transformation kinetics and discuss the underlying thermodynamics. The mechanism is likely to be a feature of many metallic glasses and metals in general, and may provide further insight into phase transition theory.

  2. DEVELOPMENT OF ALL-SOLID-STATE SENSORS FOR MEASUREMENT OF NITRIC OXIDE AND AMMONIA CONCENTRATIONS BY OPTICAL ABSORPTION IN PARTICLE-LADEN COMBUSTION EXHAUST STREAMS

    SciTech Connect

    Jerald A. Caton; Kalyan Annamalai; Robert P. Lucht

    2004-09-30

    An all-solid-state continuous-wave (cw) laser system for ultraviolet absorption measurements of the nitric oxide (NO) molecule has been developed and demonstrated. For the NO sensor, 250 nW of tunable cw ultraviolet radiation is produced by sum-frequency-mixing of 532-nm radiation from a diode-pumped Nd:YAG laser and tunable 395-nm radiation from an external cavity diode laser (ECDL). The sum-frequency-mixing process occurs in a beta-barium borate crystal. The nitric oxide absorption measurements are performed by tuning the ECDL and scanning the sum-frequency-mixed radiation over strong nitric oxide absorption lines near 226 nm. In Year 1 of the research, the nitric oxide sensor was used for measurements in the exhaust of a coal-fired laboratory combustion facility. The Texas A&M University boiler burner facility is a 30 kW (100,000 Btu/hr) downward-fired furnace with a steel shell encasing ceramic insulation. Measurements of nitric oxide concentration in the exhaust stream were performed after modification of the facility for laser based NOx diagnostics. The diode-laser-based ultraviolet absorption measurements were successful even when the beam was severely attenuated by particulate in the exhaust stream and window fouling. Single-laser-sweep measurements were demonstrated with an effective time resolution of 100 msec, limited at this time by the scan rate of our mechanically tuned ECDL system. In Year 2 described in this progress report, the Toptica ECDL in the original system was replaced with a Sacher Lasers ECDL. The mode-hop-free tuning range and tuning rate of the Toptica ECDL were 25 GHz and a few Hz, respectively. The mode-hop-free tuning range and tuning rate of the Sacher Lasers ECDL were 90 GHz and a few hundred Hz, respectively. The Sacher Lasers ECDL thus allows us to scan over the entire NO absorption line and to determine the absorption baseline with increased accuracy and precision. The increased tuning rate is an advantage in that data can be

  3. Development of All-Solid-State Sensors for Measurement of Nitric Oxide and Ammonia Concentrations by Optical Absorption in Particle-Laden Combustion Exhaust Streams

    SciTech Connect

    Jerald A. Caton; Kalyan Annamalai; Robert P. Lucht

    2006-12-31

    An all-solid-state continuous-wave (cw) laser system for ultraviolet absorption measurements of the nitric oxide (NO) molecule has been developed and demonstrated. For the NO sensor, 250 nW of tunable cw ultraviolet radiation is produced by sum-frequency-mixing of 532-nm radiation from a diode-pumped Nd:YAG laser and tunable 395-nm radiation from an external cavity diode laser (ECDL). The sum-frequency-mixing process occurs in a beta-barium borate crystal. The nitric oxide absorption measurements are performed by tuning the ECDL and scanning the sum-frequency-mixed radiation over strong nitric oxide absorption lines near 226 nm. In Year 1 of the research, the nitric oxide sensor was used for measurements in the exhaust of a coal-fired laboratory combustion facility. The Texas A&M University boiler burner facility is a 30 kW (100,000 Btu/hr) downward-fired furnace with a steel shell encasing ceramic insulation. Measurements of nitric oxide concentration in the exhaust stream were performed after modification of the facility for laser based NOx diagnostics. The diode-laser-based ultraviolet absorption measurements were successful even when the beam was severely attenuated by particulate in the exhaust stream and window fouling. Single-laser-sweep measurements were demonstrated with an effective time resolution of 100 msec, limited at this time by the scan rate of our mechanically tuned ECDL system. In Year 2, the Toptica ECDL in the original system was replaced with a Sacher Lasers ECDL. The mode-hop-free tuning range and tuning rate of the Toptica ECDL were 25 GHz and a few Hz, respectively. The mode-hop-free tuning range and tuning rate of the Sacher Lasers ECDL were 90 GHz and a few hundred Hz, respectively. The Sacher Lasers ECDL thus allows us to scan over the entire NO absorption line and to determine the absorption baseline with increased accuracy and precision. The increased tuning rate is an advantage in that data can be acquired much more rapidly and the

  4. Development of All-Solid-State Sensors for Measurement of Nitric Oxide and Ammonia Concentrations by Optical Absorption in Particle-Laden Combustion Exhaust Streams

    SciTech Connect

    Jerald A. Caton; Kalyan Annamalai; Robert P. Lucht

    2005-09-30

    An all-solid-state continuous-wave (cw) laser system for ultraviolet absorption measurements of the nitric oxide (NO) molecule has been developed and demonstrated. For the NO sensor, 250 nW of tunable cw ultraviolet radiation is produced by sum-frequency-mixing of 532-nm radiation from a diode-pumped Nd:YAG laser and tunable 395-nm radiation from an external cavity diode laser (ECDL). The sum-frequency-mixing process occurs in a beta-barium borate crystal. The nitric oxide absorption measurements are performed by tuning the ECDL and scanning the sum-frequency-mixed radiation over strong nitric oxide absorption lines near 226 nm. In Year 1 of the research, the nitric oxide sensor was used for measurements in the exhaust of a coal-fired laboratory combustion facility. The Texas A&M University boiler burner facility is a 30 kW (100,000 Btu/hr) downward-fired furnace with a steel shell encasing ceramic insulation. Measurements of nitric oxide concentration in the exhaust stream were performed after modification of the facility for laser based NOx diagnostics. The diode-laser-based ultraviolet absorption measurements were successful even when the beam was severely attenuated by particulate in the exhaust stream and window fouling. Single-laser-sweep measurements were demonstrated with an effective time resolution of 100 msec, limited at this time by the scan rate of our mechanically tuned ECDL system. In Year 2, the Toptica ECDL in the original system was replaced with a Sacher Lasers ECDL. The mode-hop-free tuning range and tuning rate of the Toptica ECDL were 25 GHz and a few Hz, respectively. The mode-hop-free tuning range and tuning rate of the Sacher Lasers ECDL were 90 GHz and a few hundred Hz, respectively. The Sacher Lasers ECDL thus allows us to scan over the entire NO absorption line and to determine the absorption baseline with increased accuracy and precision. The increased tuning rate is an advantage in that data can be acquired much more rapidly and the

  5. Microgravity Particle Dynamics

    NASA Technical Reports Server (NTRS)

    Clark, Ivan O.; Johnson, Edward J.

    1996-01-01

    This research seeks to identify the experiment design parameters for future flight experiments to better resolve the effects of thermal and velocity gradients on gas-solid flows. By exploiting the reduced body forces and minimized thermal convection current of reduced gravity experiments, features of gas-solid flow normally masked by gravitationally induced effects can be studied using flow regimes unattainable under unigravity. This paper assesses the physical scales of velocity, length, time, thermal gradient magnitude, and velocity gradient magnitude likely to be involved in laminar gas-solid multiphase flight experiments for 1-100 micro-m particles.

  6. Solid propellants.

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Hutchison, J. J.

    1972-01-01

    The basic principles underlying propulsion by rocket motor are examined together with the configuration of a solid propellant motor. Solid propellants and their preparation are discussed, giving attention to homogeneous propellants, composite propellants, energetic considerations in choosing a solid propellant, the processing of composite propellants, and some examples of new developments. The performance of solid propellants is investigated, taking into account characteristics velocity, the specific impulse, and performance calculations. Aspects of propellant development considered include nonperformance requirements for solid propellants, the approach to development, propellant mechanical properties, and future trends.

  7. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Hugo S. Caram; Natalie Foster

    1999-07-01

    The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and requires accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained.

  8. WET SOLIDS FLOW ENHANCEMENT

    SciTech Connect

    Hugo S. Caram; Natalie Foster

    1998-03-30

    The strain-stress behavior of a wet granular media was measured using a split Parfitt tensile tester. In all cases the stress increases linearly with distance until the maximum uniaxial tensile stress is reached. The stress then decreases exponentially with distance after this maximum is reached. The linear region indicates that wet solids behave elastically for stresses below the tensile stresses and can store significant elastic energy. The elastic deformation cannot be explained by analyzing the behavior of individual capillary bridges and may require accounting for the deformation of the solids particles. The elastic modulus of the wet granular material remains unexplained.

  9. [Hereditary movement disorders].

    PubMed

    Schulz, J B

    2007-12-01

    Hereditary movement disorders comprise a group of genetically defined diseases characterized by an impaired control of movements, ataxia and/or spasticity. Affected individuals are disabled, their quality of life significantly reduced and their life expectancy shortened. One or more genetic causes have been identified for many of these diseases, including Huntington's disease, Wilson's disease, spinocerebellar ataxias, recessive ataxias, hereditary spastic paraplegia and hereditary dystonias. Due to their characteristic molecular and biochemical pathogenesis, these rare diseases can often serve as models for more common disorders such as Alzheimer's disease or Parkinson's disease. The primary tasks of the German Network of Hereditary Movement Disorders (GeNeMove), funded by the German Ministry for Education and Research (BMBF), are to co-ordinate basic scientific research and clinical research into rare hereditary movement disorders and to improve the cooperation between the German centers specializing in hereditary movement disorders. For each of the diseases in its scope, GeNeMove works at creating standardized documentation of symptoms and the disease's progressive course over time; developing rating scales for clinical examinations and guidelines for therapy; improving genetic testing; fostering genetic research; and collecting samples of DNA, tissue, CSF and blood from sufferers of the disease for biobanks.

  10. Psychostimulants and Movement Disorders

    PubMed Central

    Asser, Andres; Taba, Pille

    2015-01-01

    Psychostimulants are a diverse group of substances with their main psychomotor effects resembling those of amphetamine, methamphetamine, cocaine, or cathinone. Due to their potential as drugs of abuse, recreational use of most of these substances is illegal since 1971 Convention on Psychotropic Substances. In recent years, new psychoactive substances have emerged mainly as synthetic cathinones with new molecules frequently complementing the list. Psychostimulant related movement disorders are a known entity often seen in emergency rooms around the world. These admissions are becoming more frequent as are fatalities associated with drug abuse. Still the legal constraints of the novel synthetic molecules are bypassed. At the same time, chronic and permanent movement disorders are much less frequently encountered. These disorders frequently manifest as a combination of movement disorders. The more common symptoms include agitation, tremor, hyperkinetic and stereotypical movements, cognitive impairment, and also hyperthermia and cardiovascular dysfunction. The pathophysiological mechanisms behind the clinical manifestations have been researched for decades. The common denominator is the monoaminergic signaling. Dopamine has received the most attention but further research has demonstrated involvement of other pathways. Common mechanisms linking psychostimulant use and several movement disorders exist. PMID:25941511

  11. Pursuit Eye Movements

    NASA Technical Reports Server (NTRS)

    Krauzlis, Rich; Stone, Leland; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    When viewing objects, primates use a combination of saccadic and pursuit eye movements to stabilize the retinal image of the object of regard within the high-acuity region near the fovea. Although these movements involve widespread regions of the nervous system, they mix seamlessly in normal behavior. Saccades are discrete movements that quickly direct the eyes toward a visual target, thereby translating the image of the target from an eccentric retinal location to the fovea. In contrast, pursuit is a continuous movement that slowly rotates the eyes to compensate for the motion of the visual target, minimizing the blur that can compromise visual acuity. While other mammalian species can generate smooth optokinetic eye movements - which track the motion of the entire visual surround - only primates can smoothly pursue a single small element within a complex visual scene, regardless of the motion elsewhere on the retina. This ability likely reflects the greater ability of primates to segment the visual scene, to identify individual visual objects, and to select a target of interest.

  12. Movement as utopia.

    PubMed

    Couton, Philippe; López, José Julián

    2009-10-01

    Opposition to utopianism on ontological and political grounds has seemingly relegated it to a potentially dangerous form of antiquated idealism. This conclusion is based on a restrictive view of utopia as excessively ordered panoptic discursive constructions. This overlooks the fact that, from its inception, movement has been central to the utopian tradition. The power of utopianism indeed resides in its ability to instantiate the tension between movement and place that has marked social transformations in the modern era. This tension continues in contemporary discussions of movement-based social processes, particularly international migration and related identity formations, such as open borders transnationalism and cosmopolitanism. Understood as such, utopia remains an ongoing and powerful, albeit problematic instrument of social and political imagination. PMID:20027697

  13. Movement as utopia.

    PubMed

    Couton, Philippe; López, José Julián

    2009-10-01

    Opposition to utopianism on ontological and political grounds has seemingly relegated it to a potentially dangerous form of antiquated idealism. This conclusion is based on a restrictive view of utopia as excessively ordered panoptic discursive constructions. This overlooks the fact that, from its inception, movement has been central to the utopian tradition. The power of utopianism indeed resides in its ability to instantiate the tension between movement and place that has marked social transformations in the modern era. This tension continues in contemporary discussions of movement-based social processes, particularly international migration and related identity formations, such as open borders transnationalism and cosmopolitanism. Understood as such, utopia remains an ongoing and powerful, albeit problematic instrument of social and political imagination.

  14. The Black Civil Rights Movement.

    ERIC Educational Resources Information Center

    Burson, George

    1986-01-01

    Presents part of the Aspen High School curriculum about the United States civil rights movement. Focuses on why Blacks were segregated and disenfranchised prior to the movement, why the movement took place, what were the results of the movement, and what is the present condition of Blacks in American society. (JDH)

  15. Correcting Slightly Less Simple Movements

    ERIC Educational Resources Information Center

    Aivar, M. P.; Brenner, E.; Smeets, J. B. J.

    2005-01-01

    Many studies have analysed how goal directed movements are corrected in response to changes in the properties of the target. However, only simple movements to single targets have been used in those studies, so little is known about movement corrections under more complex situations. Evidence from studies that ask for movements to several targets…

  16. Combining modules for movement.

    PubMed

    Bizzi, E; Cheung, V C K; d'Avella, A; Saltiel, P; Tresch, M

    2008-01-01

    We review experiments supporting the hypothesis that the vertebrate motor system produces movements by combining a small number of units of motor output. Using a variety of approaches such as microstimulation of the spinal cord, NMDA iontophoresis, and an examination of natural behaviors in intact and deafferented animals we have provided evidence for a modular organization of the spinal cord. A module is a functional unit in the spinal cord that generates a specific motor output by imposing a specific pattern of muscle activation. Such an organization might help to simplify the production of movements by reducing the degrees of freedom that need to be specified.

  17. Experimental Methods to Estimate Accumulated Solids in Nuclear Waste Tanks - 13313

    SciTech Connect

    Duignan, Mark R.; Steeper, Timothy J.; Steimke, John L.

    2013-07-01

    The Department of Energy has a large number of nuclear waste tanks. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles, e.g., plutonium containing, could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids and supernatant were charged to the test tank and rotating liquid jets were used to remove most of the solids. Then the volume and shape of the residual solids and the spatial concentration profiles for the surrogate for plutonium were measured. This paper discusses the overall test results, which indicated heavy solids only accumulate during the first few transfer cycles, along with the techniques and equipment designed and employed in the test. Those techniques include: - Magnetic particle separator to remove stainless steel solids, the plutonium surrogate from a flowing stream. - Magnetic wand used to manually remove stainless steel solids from samples and the tank heel. - Photographs were used to determine the volume and shape of the solids mounds by developing a composite of topographical areas. - Laser range finders to determine the volume and shape of the solids mounds. - Core sampler to determine the stainless steel solids distribution within the solids mounds. - Computer driven positioner that placed the laser range finders and the core sampler over solids mounds that accumulated on the bottom of a scaled staging tank in locations where jet velocities

  18. Modeling of Interior Ballistic Gas-Solid Flow Using a Coupled Computational Fluid Dynamics-Discrete Element Method.

    PubMed

    Cheng, Cheng; Zhang, Xiaobing

    2013-05-01

    In conventional models for two-phase reactive flow of interior ballistic, the dynamic collision phenomenon of particles is neglected or empirically simplified. However, the particle collision between particles may play an important role in dilute two-phase flow because the distribution of particles is extremely nonuniform. The collision force may be one of the key factors to influence the particle movement. This paper presents the CFD-DEM approach for simulation of interior ballistic two-phase flow considering the dynamic collision process. The gas phase is treated as a Eulerian continuum and described by a computational fluid dynamic method (CFD). The solid phase is modeled by discrete element method (DEM) using a soft sphere approach for the particle collision dynamic. The model takes into account grain combustion, particle-particle collisions, particle-wall collisions, interphase drag and heat transfer between gas and solid phases. The continuous gas phase equations are discretized in finite volume form and solved by the AUSM+-up scheme with the higher order accurate reconstruction method. Translational and rotational motions of discrete particles are solved by explicit time integrations. The direct mapping contact detection algorithm is used. The multigrid method is applied in the void fraction calculation, the contact detection procedure, and CFD solving procedure. Several verification tests demonstrate the accuracy and reliability of this approach. The simulation of an experimental igniter device in open air shows good agreement between the model and experimental measurements. This paper has implications for improving the ability to capture the complex physics phenomena of two-phase flow during the interior ballistic cycle and to predict dynamic collision phenomena at the individual particle scale.

  19. A movement ecology paradigm for unifying organismal movement research

    PubMed Central

    Nathan, Ran; Getz, Wayne M.; Revilla, Eloy; Holyoak, Marcel; Kadmon, Ronen; Saltz, David; Smouse, Peter E.

    2008-01-01

    Movement of individual organisms is fundamental to life, quilting our planet in a rich tapestry of phenomena with diverse implications for ecosystems and humans. Movement research is both plentiful and insightful, and recent methodological advances facilitate obtaining a detailed view of individual movement. Yet, we lack a general unifying paradigm, derived from first principles, which can place movement studies within a common context and advance the development of a mature scientific discipline. This introductory article to the Movement Ecology Special Feature proposes a paradigm that integrates conceptual, theoretical, methodological, and empirical frameworks for studying movement of all organisms, from microbes to trees to elephants. We introduce a conceptual framework depicting the interplay among four basic mechanistic components of organismal movement: the internal state (why move?), motion (how to move?), and navigation (when and where to move?) capacities of the individual and the external factors affecting movement. We demonstrate how the proposed framework aids the study of various taxa and movement types; promotes the formulation of hypotheses about movement; and complements existing biomechanical, cognitive, random, and optimality paradigms of movement. The proposed framework integrates eclectic research on movement into a structured paradigm and aims at providing a basis for hypothesis generation and a vehicle facilitating the understanding of the causes, mechanisms, and spatiotemporal patterns of movement and their role in various ecological and evolutionary processes. ”Now we must consider in general the common reason for moving with any movement whatever.“ (Aristotle, De Motu Animalium, 4th century B.C.) PMID:19060196

  20. Solid lubricants

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1991-01-01

    The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

  1. [Abnormal movements. Historical notes].

    PubMed

    García-Ruiz, P J

    Most of the knowledge about movement disorders comes from the last fifty years. However, the ancients made some remarkable neurological depictions. We still can find some neurological descriptions including Parkinson's disease in the Bible, and the ancient writings of Atreya and Susruta. In addition, classic tests provide us of valuable information on historical personages, including the dystonia of Alexander the Great.

  2. Fluid Movement and Creativity

    ERIC Educational Resources Information Center

    Slepian, Michael L.; Ambady, Nalini

    2012-01-01

    Cognitive scientists describe creativity as fluid thought. Drawing from findings on gesture and embodied cognition, we hypothesized that the physical experience of fluidity, relative to nonfluidity, would lead to more fluid, creative thought. Across 3 experiments, fluid arm movement led to enhanced creativity in 3 domains: creative generation,…

  3. Posture and Movement

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Session TP3 includes short reports on: (1) Modification of Goal-Directed Arm Movements During Inflight Adaptation to Microgravity; (2) Quantitative Analysis of Motion control in Long Term Microgravity; (3) Does the Centre of Gravity Remain the Stabilised Reference during Complex Human Postural Equilibrium Tasks in Weightlessness?; and (4) Arm End-Point Trajectories Under Normal and Microgravity Environments.

  4. Measuring Facial Movement

    ERIC Educational Resources Information Center

    Ekman, Paul; Friesen, Wallace V.

    1976-01-01

    The Facial Action Code (FAC) was derived from an analysis of the anatomical basis of facial movement. The development of the method is explained, contrasting it to other methods of measuring facial behavior. An example of how facial behavior is measured is provided, and ideas about research applications are discussed. (Author)

  5. [Architecture and movement].

    PubMed

    Rivallan, Armel

    2012-01-01

    Leading an architectural project means accompanying the movement which it induces within the teams. Between questioning, uncertainty and fear, the organisational changes inherent to the new facility must be subject to constructive and ongoing exchanges. Ethics, safety and training are revised and the unit projects are sometimes modified.

  6. Managing Movement as Partnership

    ERIC Educational Resources Information Center

    Kimbrell, Sinead

    2011-01-01

    The associate director of education at Hubbard Street Dance Chicago recounts her learning and teaching through managing the Movement as Partnership program. Included are detailed descriptions of encounters with teachers and students as they create choreography reflective of their inquiry into integrating dance and literacy arts curriculum in the…

  7. Teaching the Movement

    ERIC Educational Resources Information Center

    Watson, Jamal Eric

    2012-01-01

    Every January, Charles Cobb Jr. makes the 1,100-mile trek from sunny Jacksonville, Florida, to chilly Providence, Rhode Island. For the past eight years, Cobb--a veteran of the civil rights movement who in the 1960s served as a field secretary for the Student Nonviolent Coordinating Committee (SNCC) in Mississippi--becomes a visiting professor of…

  8. Solids flow mapping in gas-solid risers

    NASA Astrophysics Data System (ADS)

    Bhusarapu, Satish Babu

    Gas-solid risers are extensively used in many industrial processes for gas-solid reactions (e.g. coal combustion and gasification) and for solid catalyzed gas phase reactions (e.g. fluid catalytic cracking, butane oxidation to maleic anhydride). Ab initio prediction of the complex multiphase fluid dynamics in risers is not yet possible, which makes reactor modeling difficult. In particular, quantification of solids flow and mixing is important. Almost all the experimental techniques used to characterize solids flow lead to appreciable errors in measured variables in large scale, high mass flux systems. In addition, none of the experimental techniques provide all the relevant data required to develop a satisfactory solids flow model. In this study, non-invasive Computer Automated Radioactive Particle Tracking (CARPT) is employed to visualize and quantify the solids dynamics and mixing in the gas-solid riser of a Circulating Fluidized Bed (CFB). A single radioactive tracer particle is monitored during its multiple visits to the riser and with an assumption of ergodicity, the following flow parameters are estimated: (a) Overall solids mass flux in the CFB loop. (b) Solids residence time distribution in the riser and down-comer. (c) Lagrangian and Eulerian solids velocity fields in a fully-developed section of the riser. This includes velocity fluctuations and components of the diffusivity tensor. The existing CARPT technique is extended to large scale systems. A new algorithm, based on a cross-correlation search, is developed for position rendition from CARPT data. Two dimensional solids holdup profiles are estimated using gamma-ray computed tomography. The image quality from the tomography data is improved by implementing an alternating minimization algorithm. This work establishes for the first time a reliable database for local solids dynamic quantities such as time-averaged velocities, Reynolds stresses, eddy diffusivities and turbulent kinetic energy. In addition

  9. Four particle exchange in solid He-3

    NASA Technical Reports Server (NTRS)

    Mcmahan, A. K.

    1975-01-01

    Calculations which demonstrate a physically important four-atom exchange process in bodycentered cubic He crystal and thus an important four-spin term in the exchange Hamiltonian are discussed. A simple, mean-field analysis of this Hamiltonian appears to account for a number of the perplexing properties of bodycentered cubic He crystal. It is suggested that an understanding of other properties may require treatment of the exact four-spin term.

  10. Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 1, in-situ measurements of flow dynamics, tracer particle movement and video imagery from the summer of 2009

    USGS Publications Warehouse

    McCoy, Scott W.; Coe, Jeffrey A.; Kean, Jason W.; Tucker, Greg E.; Staley, Dennis M.; Wasklewicz, Thad A.

    2011-01-01

    Debris flows initiated by surface-water runoff during short duration, moderate- to high-intensity rainfall are common in steep, rocky, and sparsely vegetated terrain. Yet large uncertainties remain about the potential for a flow to grow through entrainment of loose debris, which make formulation of accurate mechanical models of debris-flow routing difficult. Using a combination of in situ measurements of debris flow dynamics, video imagery, tracer rocks implanted with passive integrated transponders (PIT) and pre- and post-flow 2-cm resolution digital terrain models (terrain data presented in a companion paper by STALEY et alii, 2011), we investigated the entrainment and transport response of debris flows at Chalk Cliffs, CO, USA. Four monitored events during the summer of 2009 all initiated from surface-water runoff, generally less than an hour after the first measurable rain. Despite reach-scale morphology that remained relatively constant, the four flow events displayed a range of responses, from long-runout flows that entrained significant amounts of channel sediment and dammed the main-stem river, to smaller, short-runout flows that were primarily depositional in the upper basin. Tracer-rock travel-distance distributions for these events were bimodal; particles either remained immobile or they travelled the entire length of the catchment. The long-runout, large-entrainment flow differed from the other smaller flows by the following controlling factors: peak 10-minute rain intensity; duration of significant flow in the channel; and to a lesser extent, peak surge depth and velocity. Our growing database of natural debris-flow events can be used to develop linkages between observed debris-flow transport and entrainment responses and the controlling rainstorm characteristics and flow properties.

  11. On Characterizing Particle Shape

    NASA Technical Reports Server (NTRS)

    Ennis, Bryan J.; Rickman, Douglas; Rollins, A. Brent; Ennis, Brandon

    2014-01-01

    It is well known that particle shape affects flow characteristics of granular materials, as well as a variety of other solids processing issues such as compaction, rheology, filtration and other two-phase flow problems. The impact of shape crosses many diverse and commercially important applications, including pharmaceuticals, civil engineering, metallurgy, health, and food processing. Two applications studied here include the dry solids flow of lunar simulants (e.g. JSC-1, NU-LHT-2M, OB-1), and the flow properties of wet concrete, including final compressive strength. A multi-dimensional generalized, engineering method to quantitatively characterize particle shapes has been developed, applicable to both single particle orientation and multi-particle assemblies. The two-dimension, three dimension inversion problem is also treated, and the application of these methods to DEM model particles will be discussed. In the case of lunar simulants, flow properties of six lunar simulants have been measured, and the impact of particle shape on flowability - as characterized by the shape method developed here -- is discussed, especially in the context of three simulants of similar size range. In the context of concrete processing, concrete construction is a major contributor to greenhouse gas production, of which the major contributor is cement binding loading. Any optimization in concrete rheology and packing that can reduce cement loading and improve strength loading can also reduce currently required construction safety factors. The characterization approach here is also demonstrated for the impact of rock aggregate shape on concrete slump rheology and dry compressive strength.

  12. Oxidative particle mixtures for groundwater treatment

    DOEpatents

    Siegrist, Robert L.; Murdoch, Lawrence C.

    2000-01-01

    The invention is a method and a composition of a mixture for degradation and immobilization of contaminants in soil and groundwater. The oxidative particle mixture and method includes providing a material having a minimal volume of free water, mixing at least one inorganic oxidative chemical in a granular form with a carrier fluid containing a fine grained inorganic hydrophilic compound and injecting the resulting mixture into the subsurface. The granular form of the inorganic oxidative chemical dissolves within the areas of injection, and the oxidative ions move by diffusion and/or advection, therefore extending the treatment zone over a wider area than the injection area. The organic contaminants in the soil and groundwater are degraded by the oxidative ions, which form solid byproducts that can sorb significant amounts of inorganic contaminants, metals, and radionuclides for in situ treatment and immobilization of contaminants. The method and composition of the oxidative particle mixture for long-term treatment and immobilization of contaminants in soil and groundwater provides for a reduction in toxicity of contaminants in a subsurface area of contamination without the need for continued injection of treatment material, or for movement of the contaminants, or without the need for continuous pumping of groundwater through the treatment zone, or removal of groundwater from the subsurface area of contamination.

  13. Movement Coordination or Movement Interference: Visual Tracking and Spontaneous Coordination Modulate Rhythmic Movement Interference

    PubMed Central

    Romero, Veronica; Coey, Charles; Schmidt, R. C.; Richardson, Michael J.

    2012-01-01

    When an actor performs a rhythmic limb movement while observing a spatially incongruent movement he or she exhibits increased movement orthogonal to the instructed motion. Known as rhythmic movement interference, this phenomenon has been interpreted as a motor contagion effect, whereby observing the incongruent movement interferes with the intended movement and results in a motor production error. Here we test the hypothesis that rhythmic movement interference is an emergent property of rhythmic coordination. Participants performed rhythmic limb movements at a self-selected tempo while observing a computer stimulus moving in a congruent or incongruent manner. The degree to which participants visually tracked the stimulus was manipulated to influence whether participants became spontaneously entrained to the stimulus or not. Consistent with the rhythmic coordination hypothesis, participants only exhibited the rhythmic movement interference effect when they became spontaneously entrained to the incongruent stimulus. PMID:23028607

  14. On quantifying insect movements

    SciTech Connect

    Wiens, J.A.; Crist, T.O. ); Milne, B.T. )

    1993-08-01

    We elaborate on methods described by Turchin, Odendaal Rausher for quantifying insect movement pathways. We note the need to scale measurement resolution to the study insects and the questions being asked, and we discuss the use of surveying instrumentation for recording sequential positions of individuals on pathways. We itemize several measures that may be used to characterize movement pathways and illustrate these by comparisons among several Eleodes beetles occurring in shortgrass steppe. The fractal dimension of pathways may provide insights not available from absolute measures of pathway configuration. Finally, we describe a renormalization procedure that may be used to remove sequential interdependence among locations of moving individuals while preserving the basic attributes of the pathway.

  15. Movement and Movement Patterns of Early Childhood. [Complete Report].

    ERIC Educational Resources Information Center

    Sinclair, Caroline

    This study investigated the progressive development in movement and movement patterns of children ages 2-6. Data were collected over a 3-year period at six-month intervals, based on films of 57 children performing 25 motor tasks. The results are presented along two dimensions: (1) Descriptive analysis of progress of young children in movement with…

  16. The Human Potential Movement: Body/Movement/Non-Verbal Experiencing.

    ERIC Educational Resources Information Center

    Caldwell, Stratton F.

    A social, humanistic movement focusing on the needs and concerns of more advantaged, affluent persons has emerged, called the "Human Potential Movement." The emphasis of the movement centers around group processes, small group experiences, and the search for personal, interpersonal, and organizational growth. The development and emergence of…

  17. Islamist Movements in Iraq

    ERIC Educational Resources Information Center

    Social Education, 2004

    2004-01-01

    When the United States invaded Iraq in March 2003, one of its stated intentions was to inaugurate an era of Iraqi politics in which new kinds of democratic parties would emerge. However, one of the most dramatic effects of the U.S. invasion has been the boost it has given to the Islamist parties and movements that were banned under Saddam Hussein.…

  18. Particle stress and viscous compaction

    SciTech Connect

    Prasad, D.; Kytoemaa, H.K.

    1994-12-31

    This study describes the transition between the quasi-static and the viscous regimes of shearing of thin layers of spheres in a viscous fluid at high solid loadings. Experiments were conducted in a Couette-type shear cell in two complementary modes: (a) constant particle normal stress, variable solid fraction and (b) constant solid fraction, variable particle normal stress. In steady shearing under the constraint of constant solid fraction, transition from a strain rate independent stress to a linearly dependent on was found to occur with a local minimum in the stresses with respect to strain rage; correspondingly, the solid fraction assumed a maximum with respect to strain rate under conditions of constant normal stress. At sufficiently high strain rates, the mixture exhibited a linear Newtonian-like scaling between strain rate and both shear and normal stresses. These measurements of normal stress are the first since those of Bagnold (1954).

  19. Solid Hydrogen Experiments for Atomic Propellants

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2001-01-01

    This paper illustrates experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Solid particles of hydrogen were frozen in liquid helium, and observed with a video camera. The solid hydrogen particle sizes, their molecular structure transitions, and their agglomeration times were estimated. article sizes of 1.8 to 4.6 mm (0.07 to 0. 18 in.) were measured. The particle agglomeration times were 0.5 to 11 min, depending on the loading of particles in the dewar. These experiments are the first step toward visually characterizing these particles, and allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

  20. Airborne soil organic particles generated by precipitation

    NASA Astrophysics Data System (ADS)

    Wang, Bingbing; Harder, Tristan H.; Kelly, Stephen T.; Piens, Dominique S.; China, Swarup; Kovarik, Libor; Keiluweit, Marco; Arey, Bruce W.; Gilles, Mary K.; Laskin, Alexander

    2016-06-01

    Airborne organic particles play a critical role in Earth's climate, public health, air quality, and hydrological and carbon cycles. However, sources and formation mechanisms for semi-solid and solid organic particles are poorly understood and typically neglected in atmospheric models. Laboratory evidence suggests that fine particles can be formed from impaction of mineral surfaces by droplets. Here, we use chemical imaging of particles collected following rain events in the Southern Great Plains, Oklahoma, USA and after experimental irrigation to show that raindrop impaction of soils generates solid organic particles. We find that after rain events, sub-micrometre solid particles, with a chemical composition consistent with soil organic matter, contributed up to 60% of atmospheric particles. Our irrigation experiments indicate that intensive water impaction is sufficient to cause ejection of airborne soil organic particles from the soil surface. Chemical imaging and micro-spectroscopy analysis of particle physico-chemical properties suggest that these particles may have important impacts on cloud formation and efficiently absorb solar radiation. We suggest that raindrop-induced formation of solid organic particles from soils may be a widespread phenomenon in ecosystems such as agricultural systems and grasslands where soils are exposed to strong, episodic precipitation events.