Science.gov

Sample records for air flow due

  1. Control of turbulent boundary layer through air blowing due to external-flow resources

    NASA Astrophysics Data System (ADS)

    Kornilov, V. I.; Boiko, A. V.; Kavun, I. N.

    2015-07-01

    The possibility to control turbulent incompressible boundary layer using air blowing through a finely perforated wall presenting part of the streamlined flat-plate surface was examined. The control was exercised via an action on the state and characteristics of the near-wall flow exerted by controlled (through variation of external-pressure-flow velocity) blowing of air through an air intake installed on the idle side of the plate. A stable reduction of the local values of skin friction coefficient along the model, reaching 50 % at the end of the perforated area, has been demonstrated. The obtained experimental and calculated data are indicative of a possibility to model the process of turbulentboundary-layer control by air blowing due to external-flow resources.

  2. Technology Solutions Case Study: Overcoming Comfort Issues Due to Reduced Flow Room Air Mixing

    SciTech Connect

    2015-03-01

    Energy efficiency upgrades reduce heating and cooling loads on a house. With enough load reduction and if the HVAC system warrants replacement, the HVAC system is often upgraded with a more efficient, lower capacity system that meets the loads of the upgraded house. In this project, IBACOS studied when HVAC equipment is downsized and ducts are unaltered to determine conditions that could cause a supply air delivery problem and to evaluate the feasibility of modifying the duct systems using minimally invasive strategies to improve air distribution.

  3. Impact of two-way air flow due to temperature difference on preventing the entry of outdoor particles using indoor positive pressure control method.

    PubMed

    Chen, Chun; Zhao, Bin; Yang, Xudong

    2011-02-28

    Maintaining positive pressure indoors using mechanical ventilation system is a popular control method for preventing the entry of outdoor airborne particles. The idea is, as long as the supply air flow rate is larger than return air flow rate, the pressure inside the ventilated room should be positive since the superfluous air flow must exfiltrate from air leakages or other openings of the room to the outdoors. Based on experimental and theoretical analyses this paper aims to show the impact of two-way air flow due to indoor/outdoor temperature difference on preventing the entry of outdoor particles using positive pressure control method. The indoor positive pressure control method is effective only when the size of the opening area is restricted to a certain level, opening degree less than 30° in this study, due to the two-way air flow effect induced by differential temperature. The theoretical model was validated using the experimental data. The impacts of two-way air flow due to temperature difference and the supply air flow rate were also analyzed using the theoretical model as well as experimental data. For real houses, it seems that the idea about the positive pressure control method for preventing the entry of outdoor particles has a blind side.

  4. Forebody flow physics due to rotary motion

    NASA Astrophysics Data System (ADS)

    Iwanski, Kenneth Paul

    An experimental investigation of the aerodynamic behavior of an isolated forebody undergoing rotary motion was conducted in a small-scale wind tunnel. Force balance, surface pressure, and flow visualization data was acquired over a range of AOA, for a round and chined configuration of a generic tangent ogive shape. The nature of the fixed location of separation of the chined forebody develops a strong, symmetrical leeward side flowfield. In comparison, the round forebody develops a lateral asymmetry, as a function of AOA, from the naturally occurring separated flow. Quantifying the side force behavior due to the rotary motion of the two distinctively different forebody configurations will lead to a better understanding of the flowfield which plays a primary role in the overall stability and control of an air vehicle. For the round forebody, the side force behavior due to the rotary motion ( CYW ) is dependent upon flow speed (ReD), AOA, as well as the direction and magnitude of rotation ( W=wLV ). In the low AOA range, the rotary-induced flowfield is insufficient in promoting a side force development. In the high AOA range a damping in side force behavior is a result of the "moving wall" effect where the flow along the windward region of the forebody is the predominant influence. In the AOA range where an asymmetrical flowfield is established in a static environment, the rotary motion does not disrupt the natural asymmetric state of the vortices. Additionally, neither the presence of a static side force nor its direction is apparently sufficient in determining the CYW behavior from the axially-varying flowfield. The CYW behavior of the chined forebody is related to the leeward side vortices' vertical trajectory, which is a function of AOA. A slight propelling side force behavior develops in an AOA range where an increased suction develops from the upwind vortex. In the high AOA range there is a diminishing influence from the leeward side vortex suction resulting

  5. Natural Flow Air Cooled Photovoltaics

    NASA Astrophysics Data System (ADS)

    Tanagnostopoulos, Y.; Themelis, P.

    2010-01-01

    Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. Our experimental study aims to investigate the improvement in the electrical performance of a photovoltaic installation on buildings through cooling of the photovoltaic panels with natural air flow. We performed experiments using a prototype based on three silicon photovoltaic modules placed in series to simulate a typical sloping building roof with photovoltaic installation. In this system the air flows through a channel on the rear side of PV panels. The potential for increasing the heat exchange from the photovoltaic panel to the circulating air by the addition of a thin metal sheet (TMS) in the middle of air channel or metal fins (FIN) along the air duct was examined. The operation of the device was studied with the air duct closed tightly to avoid air circulation (CLOSED) and the air duct open (REF), with the thin metal sheet (TMS) and with metal fins (FIN). In each case the experiments were performed under sunlight and the operating parameters of the experimental device determining the electrical and thermal performance of the system were observed and recorded during a whole day and for several days. We collected the data and form PV panels from the comparative diagrams of the experimental results regarding the temperature of solar cells, the electrical efficiency of the installation, the temperature of the back wall of the air duct and the temperature difference in the entrance and exit of the air duct. The comparative results from the measurements determine the improvement in electrical performance of the photovoltaic cells because of the reduction of their temperature, which is achieved by the naturally circulating air.

  6. (Air flow patterns within buildings)

    SciTech Connect

    Harrje, D.T.

    1990-10-15

    As Annex 20 enters the final year, deliverables in the form of reports, guidelines, and data formats are nearing completion. The Reporting Guidelines for the Measurement of Air Flows and Related Factors in Buildings will be published by the AIVC next month and was presented to the research community at the 11th AIVC Conference. Measurement guidelines and state-of-the-art equipment descriptions are part of a comprehensive manual, Measurement Techniques Related to Air Flow Patterns Within Buildings -- An Application Guide, in the final stages of preparation in Part 2 of Annex 20, together with reports on how to estimate the effects of flow through large openings, as well as contaminant movements in buildings. The Measurement Manual will include the latest information from the AIVC. The next AIVC Conference, in Ottawa, September 1991, will feature more than 12 presentations of Annex 20 results, including the information from Part 1 which has focused on the detailed air flow patterns in a variety of single-room configurations. Both complex modelling (including CFD) and detailed measurements have been completed, and it is now desirable that added tests be made in the next months by the University of Illinois, BERL, representing the US in Part 1 for the first time.

  7. Automatic air flow control in air conditioning ducts

    NASA Technical Reports Server (NTRS)

    Obler, H. D.

    1972-01-01

    Device is designed which automatically selects air flow coming from either of two directions and which can be adjusted to desired air volume on either side. Device uses one movable and two fixed scoops which control air flow and air volume.

  8. INTERACTION OF LASER RADIATION WITH MATTER. LASER PLASMA: Structure of flows due to interaction of CO2 laser pulse pairs with a target in air

    NASA Astrophysics Data System (ADS)

    Bakeev, A. A.; Nikolashina, L. I.; Potashkin, M. N.; Prokopenko, N. V.

    1991-06-01

    An analysis is made of two pulses from an electric-discharge CO2 laser, of 6-12 μs duration and separated in time, incident on a target surrounded by air of normal density. The main attention is concentrated on breakdown of air by the second pulse at a boundary separating the "cold gas" and the plasma generated by the first pulse ("hot gas"). A gasdynamic system of waves is then generated. It consists of an absorption wave traveling along the cold gas opposite to the laser radiation and a wave propagating along the hot gas toward the target. The best agreement between the theory and experiment is obtained employing a model in which an absorption wave travels along the hot gas in an overcompressed detonation regime. The density of the radiation flux needed to maintain such a wave is 20-30% of the average density of the laser radiation flux carried by the second pulse.

  9. [Ear dysfunction due to air bag detonation?].

    PubMed

    Brehmer, D; Geidel, O; Hesse, G; Laubert, A

    2000-10-01

    Air bags are among the latest developments in extensive automobile safety systems. They successfully have saved the lives of car occupants in road accidents. Many additional injuries caused by air bags from minor to severe have been reported. With the help of two acceleration sensors, the electronic tuner amplifier records the vehicle's deceleration. This is the adequate trigger for air bag deployment, which creates an intense noise of up to 170 dB sound pressure level. This noise level can cause cochlear damage. We present two patients with otologic symptoms after spontaneous air bag deployment.

  10. Flow diagnostics in unseeded air

    NASA Technical Reports Server (NTRS)

    Miles, R.; Lempert, W.

    1990-01-01

    Several approaches are presented for the quantitative measurement of flowfield parameters in high-speed flows. The techniques are developed for the study of air flows in the Mach 2 to Mach 3 regime and can be extended to the hypersonic and subsonic regimes in a straightforward manner. Instantaneous two-dimensional cross-sectional images of the density using UV Rayleigh scattering and the measurement of velocity profiles using the RELIEF technique are shown. The RELIEF technique employs two high-powered lasers separated in frequency by the vibrational frequency of oxygen molecules to write lines across the flowfield by stimulated Raman scattering. The preliminary results indicate that the UV Rayleigh scattering may also be extended to the measurement of velocity and temperature fields by using an atomic or molecular absorption filter window, and that the RELIEF technique can be extended to marking shaped volumetric points or arrays of points in the flowfield for velocity and vorticity measurements.

  11. Air flow patterns in the operating theatre.

    PubMed

    Howorth, F H

    1980-04-01

    Bacteria-carrying particles and exhaled anaesthetic gases are the two contaminants found in the air flow patterns of operating rooms. Their origin, direction and speed were illustrated by a motion picture using Schlieren photography and smoke tracers. Compared with a conventionally well air conditioned operating theatre, it was shown that a downward flow of clean air reduced the number of bacteria-carrying particles at the wound site by sixty times. The Exflow method of achieving this without the restriction of any side panels or floor obstruction was described. The total body exhaust worn by the surgical team was shown to reduce the bacteria count by a further eleven times. Clinical results show that when both these systems are used together, patient infection was reduced from 9 per cent to between 0.3 per cent and 0.5 per cent, even when no pre-operative antibiotics were used. Anaesthetic gas pollution was measured and shown to be generally 1000 p.p.m. at the head of the patient, in induction, operating and recovery rooms, also in dental and labour rooms. A high volume low pressure active scavenging system was described together with its various attachments including one specially for paediatric scavenging. Results showed a reduction of nitrous oxide pollution to between zero and 3 p.p.m. The economy and cost effectiveness of both these pollution control systems was shown to be good due to the removal of health hazards from patients and theatre staff.

  12. Air-flow regulation system for a coal gasifier

    DOEpatents

    Fasching, George E.

    1984-01-01

    An improved air-flow regulator for a fixed-bed coal gasifier is provided which allows close air-flow regulation from a compressor source even though the pressure variations are too rapid for a single primary control loop to respond. The improved system includes a primary controller to control a valve in the main (large) air supply line to regulate large slow changes in flow. A secondary controller is used to control a smaller, faster acting valve in a secondary (small) air supply line parallel to the main line valve to regulate rapid cyclic deviations in air flow. A low-pass filter with a time constant of from 20 to 50 seconds couples the output of the secondary controller to the input of the primary controller so that the primary controller only responds to slow changes in the air-flow rate, the faster, cyclic deviations in flow rate sensed and corrected by the secondary controller loop do not reach the primary controller due to the high frequency rejection provided by the filter. This control arrangement provides at least a factor of 5 improvement in air-flow regulation for a coal gasifier in which air is supplied by a reciprocating compressor through a surge tank.

  13. Seismic attenuation due to wave-induced flow

    SciTech Connect

    Pride, S.R.; Berryman, J.G.; Harris, J.M.

    2003-10-09

    Analytical expressions for three P-wave attenuation mechanisms in sedimentary rocks are given a unified theoretical framework. Two of the models concern wave-induced flow due to heterogeneity in the elastic moduli at mesoscopic scales (scales greater than grain sizes but smaller than wavelengths). In the first model, the heterogeneity is due to lithological variations (e.g., mixtures of sands and clays) with a single fluid saturating all the pores. In the second model, a single uniform lithology is saturated in mesoscopic ''patches'' by two immiscible fluids (e.g., air and water). In the third model, the heterogeneity is at ''microscopic'' grain scales (broken grain contacts and/or micro-cracks in the grains) and the associated fluid response corresponds to ''squirt flow''. The model of squirt flow derived here reduces to proper limits as any of the fluid bulk modulus, crack porosity, and/or frequency is reduced to zero. It is shown that squirt flow is incapable of explaining the measured level of loss (10{sup -2} < Q{sup -1} < 10{sup -1}) within the seismic band of frequencies (1 to 10{sup 4} Hz); however, either of the two mesoscopic scale models easily produce enough attenuation to explain the field data.

  14. Combustion in High Speed Air Flows.

    DTIC Science & Technology

    1982-05-01

    objective is the analysis of reacting multiphase flows in advanced air-breathing propulsion systems. This work involves the formulation and evaluation...of new theoretical descriptions of multiphase turbulent mixing and chemical kinetic phenomena in subsonic and supersonic air flows , and the gen...area involves the development of analyti- cal models of the phenomena occurring in the multiphase turbulent reacting flows involved in spray flame

  15. A clean air continuous flow propulsion facility

    NASA Technical Reports Server (NTRS)

    Krauss, R. H.; Mcdaniel, J. C., Jr.

    1992-01-01

    Consideration is given to a contaminant-free, high enthalpy, continuous flow facility designed to obtain detailed code validation measurements of high speed combustion. The facility encompasses uncontaminated air temperature control to within 5 K, fuel temperature control to 2 K, a ceramic flow straightener, drying of inlet air, and steady state continuous operation. The air heating method provides potential for independent control of contaminant level by injection, mixing, and heating upstream. Particular attention is given to extension of current capability of 1250 K total air temperature, which simulates Scramjet enthalpy at Mach 5.

  16. A clean air continuous flow propulsion facility

    NASA Technical Reports Server (NTRS)

    Krauss, R. H.; Mcdaniel, J. C., Jr.

    1992-01-01

    Consideration is given to a contaminant-free, high enthalpy, continuous flow facility designed to obtain detailed code validation measurements of high speed combustion. The facility encompasses uncontaminated air temperature control to within 5 K, fuel temperature control to 2 K, a ceramic flow straightener, drying of inlet air, and steady state continuous operation. The air heating method provides potential for independent control of contaminant level by injection, mixing, and heating upstream. Particular attention is given to extension of current capability of 1250 K total air temperature, which simulates Scramjet enthalpy at Mach 5.

  17. Laminar Flow Breakdown due to Particle Interactions

    DTIC Science & Technology

    2012-08-01

    effect on the boundary layer when encountering cirrus cloud , is incomplete. The observed performance degradations [5, 9] have been attributed to the...crystals as occurring in cirrus cloud would have a detrimental effect on the performance of Laminar Flow Control (LFC) systems. During flight tests of...full chord suction type LFC systems aboard two X-21 aircraft, laminar flow was entirely lost when entering thick cirrus cloud and degraded even in

  18. Minimum Detectable Air Velocity by Thermal Flow Sensors

    PubMed Central

    Issa, Safir; Lang, Walter

    2013-01-01

    Miniaturized thermal flow sensors have opened the doors for a large variety of new applications due to their small size, high sensitivity and low power consumption. Theoretically, very small detection limits of air velocity of some micrometers per second are achievable. However, the superimposed free convection is the main obstacle which prevents reaching these expected limits. Furthermore, experimental investigations are an additional challenge since it is difficult to generate very low flows. In this paper, we introduce a physical method, capable of generating very low flow values in the mixed convection region. Additionally, we present the sensor characteristic curves at the zero flow case and in the mixed convection region. Results show that the estimated minimum detectable air velocity by the presented method is 0.8 mm/s. The equivalent air velocity to the noise level of the sensor at the zero flow case is about 0.13 mm/s. PMID:23966190

  19. Health woes tied to low air flow

    SciTech Connect

    Barber, J.

    1984-01-23

    Occupants in buildings with heating, ventilating, and air conditioning (HVAC) systems which limit fresh air flow may suffer a variety of illnesses because of the buildup of noxious contaminants. Building managers need to continue conservation efforts, but they should also meet the air standards set by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) which are in the process of being strengthened. Cases of building sickness caused by indoor air pollution have increased during the past decade, prompting ASHRAE to expedite the revision of its specifications.

  20. Air flow in the human nasal cavity

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Vetlutsky, V. N.; Ganimedov, V. L.; Muchnaya, M. I.; Shepelenko, V. N.; Melnikov, M. N.; Savina, A. A.

    2010-03-01

    A mathematical model of the air flow in the human nasal cavity is developed under the assumption of a turbulent viscous air flow. The shape of the nasal cavity is modeled with the use of the Gambit graphical software system and tomography data. A numerical solution is obtained by using the Fluent commercial software system. Calculations are performed for various variants of construction of the human nasal cavity.

  1. Simulator Of Rain In Flowing Air

    NASA Technical Reports Server (NTRS)

    Clayton, Richard M.; Cho, Young I.; Shakkottai, Parthasarathy; Back, Lloyd H.

    1989-01-01

    Report describes relatively inexpensive apparatus that creates simulated precipitation from drizzle to heavy rain in flowing air. Small, positive-displacement pump and water-injecting device positioned at low-airspeed end of converging section of wind tunnel 10 in. in diameter. Drops injected by array entrained in flow of air as it accelerates toward narrower outlet, 15 in. downstream. Outlet 5 in. in diameter.

  2. Air flow in a collapsing cavity

    NASA Astrophysics Data System (ADS)

    Peters, Ivo R.; Gekle, Stephan; Lohse, Detlef; van der Meer, Devaraj

    2013-03-01

    We experimentally study the airflow in a collapsing cavity created by the impact of a circular disc on a water surface. We measure the air velocity in the collapsing neck in two ways: Directly, by means of employing particle image velocimetry of smoke injected into the cavity and indirectly, by determining the time rate of change of the volume of the cavity at pinch-off and deducing the air flow in the neck under the assumption that the air is incompressible. We compare our experiments to boundary integral simulations and show that close to the moment of pinch-off, compressibility of the air starts to play a crucial role in the behavior of the cavity. Finally, we measure how the air flow rate at pinch-off depends on the Froude number and explain the observed dependence using a theoretical model of the cavity collapse.

  3. Air-water flow in subsurface systems

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  4. Compressible Flow Tables for Air

    NASA Technical Reports Server (NTRS)

    Burcher, Marie A.

    1947-01-01

    This paper contains a tabulation of functions of the Mach number which are frequently used in high-speed aerodynamics. The tables extend from M = 0 to M = 10.0 in increments of 0.01 and are based on the assumption that air is a perfect gas having a specific heat ratio of 1.400.

  5. Human health risks in megacities due to air pollution

    NASA Astrophysics Data System (ADS)

    Gurjar, B. R.; Jain, A.; Sharma, A.; Agarwal, A.; Gupta, P.; Nagpure, A. S.; Lelieveld, J.

    2010-11-01

    This study evaluates the health risks in megacities in terms of mortality and morbidity due to air pollution. A new spreadsheet model, Risk of Mortality/Morbidity due to Air Pollution (Ri-MAP), is used to estimate the excess numbers of deaths and illnesses. By adopting the World Health Organization (WHO) guideline concentrations for the air pollutants SO 2, NO 2 and total suspended particles (TSP), concentration-response relationships and a population attributable-risk proportion concept are employed. Results suggest that some megacities like Los Angeles, New York, Osaka Kobe, Sao Paulo and Tokyo have very low excess cases in total mortality from these pollutants. In contrast, the approximate numbers of cases is highest in Karachi (15,000/yr) characterized by a very high concentration of total TSP (˜670 μg m -3). Dhaka (7000/yr), Beijing (5500/yr), Karachi (5200/yr), Cairo (5000/yr) and Delhi (3500/yr) rank highest with cardiovascular mortality. The morbidity (hospital admissions) due to Chronic Obstructive Pulmonary Disease (COPD) follows the tendency of cardiovascular mortality. Dhaka and Karachi lead the rankings, having about 2100/yr excess cases, while Osaka-Kobe (˜20/yr) and Sao Paulo (˜50/yr) are at the low end of all megacities considered. Since air pollution is increasing in many megacities, and our database of measured pollutants is limited to the period up to 2000 and does not include all relevant components (e.g. O 3), these numbers should be interpreted as lower limits. South Asian megacities most urgently need improvement of air quality to prevent excess mortality and morbidity due to exceptionally high levels of air pollution. The risk estimates obtained from Ri-MAP present a realistic baseline evaluation for the consequences of ambient air pollution in comparison to simple air quality indices, and can be expanded and improved in parallel with the development of air pollution monitoring networks.

  6. Numerical modelling of air-water flows in sewer drops.

    PubMed

    Beceiro, Paula; Almeida, Maria do Céu; Matos, Jorge

    2017-07-01

    The presence of dissolved oxygen (DO) in water flows is an important factor to ensure the aerobic conditions recognised as beneficial to preventing the occurrence of detrimental effects. The incorporation of DO in wastewater flowing in sewer systems is a process widely investigated in order to quantify the effect of continuous reaeration through the air-liquid interface or air entrained due to the presence of singularities such as drops or junctions. The location of sewer drops to enhance air entrainment and subsequently reaeration is an effective practice to promote aerobic conditions in sewers. In the present paper, vertical drops, backdrops and stepped drops were modelled using the computational fluid dynamics (CFD) code FLOW-3D(®) to evaluate the air-water flows due to the turbulence induced by the presence of these types of structures. An assessment of the hydraulic variables and an analysis of the air entrainment based on the available experimental studies were carried out. The results of the CFD models for these structures were validated using measurements of discharge, pressure head and water depth obtained in the corresponding physical models. A very good fit was obtained for the hydraulic behaviour. After validation of numerical models, analysis of the air entrainment was carried out.

  7. Dynamo quenching due to shear flow.

    PubMed

    Leprovost, Nicolas; Kim, Eun-jin

    2008-04-11

    We provide a theory of dynamo (alpha effect) and momentum transport in three-dimensional magnetohydrodynamics. For the first time, we show that the alpha effect is reduced by the shear even in the absence of magnetic field. The alpha effect is further suppressed by magnetic fields well below equipartition (with the large-scale flow) with different scalings depending on the relative strength of shear and magnetic field. The turbulent viscosity is also found to be significantly reduced by shear and magnetic fields, with positive value. These results suggest a crucial effect of shear and magnetic field on dynamo quenching and momentum transport reduction, with important implications for laboratory and astrophysical plasmas, in particular, for the dynamics of the Sun.

  8. Air flow through poppet valves

    NASA Technical Reports Server (NTRS)

    Lewis, G W; Nutting, E M

    1920-01-01

    Report discusses the comparative continuous flow characteristics of single and double poppet valves. The experimental data presented affords a direct comparison of valves, single and in pairs of different sizes, tested in a cylinder designed in accordance with current practice in aviation engines.

  9. 40 CFR 91.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Intake air flow measurement... Procedures § 91.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure the air flow over the...

  10. 40 CFR 91.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Intake air flow measurement... Procedures § 91.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure the air flow over the...

  11. 40 CFR 91.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Intake air flow measurement... Procedures § 91.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure the air flow over the...

  12. 40 CFR 91.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Intake air flow measurement... Procedures § 91.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure the air flow over the...

  13. Upwelling Southwest of Iceland Due to Quasi-Geostrophic Flow

    DTIC Science & Technology

    1990-05-22

    relatively nutrient rich, possibly due to turbulent mixing as it flows across the Reykjanes Ridge " (Thordardottir and Stefansson, 1977). Stefansson...occurs with flow over a bump or ridge , causes a decrease in 6 leading to anticyclonic flow. A change in the current flow after it passes over the...topography on upwelling. They used a cylindrical tank to simulate an ocean basin and created a ridge system with wind stress and clockwise rotation. They

  14. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method...

  15. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement...

  16. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement...

  17. Flow damping due to stochastization of the magnetic field

    PubMed Central

    Ida, K.; Yoshinuma, M.; Tsuchiya, H.; Kobayashi, T.; Suzuki, C.; Yokoyama, M.; Shimizu, A.; Nagaoka, K.; Inagaki, S.; Itoh, K.; Akiyama, T.; Emoto, M.; Evans, T.; Dinklage, A.; Du, X.; Fujii, K.; Goto, M.; Goto, T.; Hasuo, M.; Hidalgo, C.; Ichiguchi, K.; Ishizawa, A.; Jakubowski, M.; Kamiya, K.; Kasahara, H.; Kawamura, G.; Kato, D.; Kobayashi, M.; Morita, S.; Mukai, K.; Murakami, I.; Murakami, S.; Narushima, Y.; Nunami, M.; Ohdach, S.; Ohno, N.; Osakabe, M.; Pablant, N.; Sakakibara, S.; Seki, T.; Shimozuma, T.; Shoji, M.; Sudo, S.; Tanaka, K.; Tokuzawa, T.; Todo, Y.; Wang, H.; Yamada, H.; Takeiri, Y.; Mutoh, T.; Imagawa, S.; Mito, T.; Nagayama, Y.; Watanabe, K. Y.; Ashikawa, N.; Chikaraishi, H.; Ejiri, A.; Furukawa, M.; Fujita, T.; Hamaguchi, S.; Igami, H.; Isobe, M.; Masuzaki, S.; Morisaki, T.; Motojima, G.; Nagasaki, K.; Nakano, H.; Oya, Y.; Suzuki, Y.; Sakamoto, R.; Sakamoto, M.; Sanpei, A.; Takahashi, H.; Tokitani, M.; Ueda, Y.; Yoshimura, Y.; Yamamoto, S.; Nishimura, K.; Sugama, H.; Yamamoto, T.; Idei, H.; Isayama, A.; Kitajima, S.; Masamune, S.; Shinohara, K.; Bawankar, P. S.; Bernard, E.; von Berkel, M.; Funaba, H.; Huang, X. L.; Ii, T.; Ido, T.; Ikeda, K.; Kamio, S.; Kumazawa, R.; Moon, C.; Muto, S.; Miyazawa, J.; Ming, T.; Nakamura, Y.; Nishimura, S.; Ogawa, K.; Ozaki, T.; Oishi, T.; Ohno, M.; Pandya, S.; Seki, R.; Sano, R.; Saito, K.; Sakaue, H.; Takemura, Y.; Tsumori, K.; Tamura, N.; Tanaka, H.; Toi, K.; Wieland, B.; Yamada, I.; Yasuhara, R.; Zhang, H.; Kaneko, O.; Komori, A.

    2015-01-01

    The driving and damping mechanism of plasma flow is an important issue because flow shear has a significant impact on turbulence in a plasma, which determines the transport in the magnetized plasma. Here we report clear evidence of the flow damping due to stochastization of the magnetic field. Abrupt damping of the toroidal flow associated with a transition from a nested magnetic flux surface to a stochastic magnetic field is observed when the magnetic shear at the rational surface decreases to 0.5 in the large helical device. This flow damping and resulting profile flattening are much stronger than expected from the Rechester–Rosenbluth model. The toroidal flow shear shows a linear decay, while the ion temperature gradient shows an exponential decay. This observation suggests that the flow damping is due to the change in the non-diffusive term of momentum transport. PMID:25569268

  18. Anthropogenic heating of the urban environment due to air conditioning

    NASA Astrophysics Data System (ADS)

    Salamanca, F.; Georgescu, M.; Mahalov, A.; Moustaoui, M.; Wang, M.

    2014-05-01

    This article investigates the effect of air conditioning (AC) systems on air temperature and examines their electricity consumption for a semiarid urban environment. We simulate a 10 day extreme heat period over the Phoenix metropolitan area (U.S.) with the Weather Research and Forecasting model coupled to a multilayer building energy scheme. The performance of the modeling system is evaluated against 10 Arizona Meteorological Network weather stations and one weather station maintained by the National Weather Service for air temperature, wind speed, and wind direction. We show that explicit representation of waste heat from air conditioning systems improved the 2 m air temperature correspondence to observations. Waste heat release from AC systems was maximum during the day, but the mean effect was negligible near the surface. However, during the night, heat emitted from AC systems increased the mean 2 m air temperature by more than 1°C for some urban locations. The AC systems modified the thermal stratification of the urban boundary layer, promoting vertical mixing during nighttime hours. The anthropogenic processes examined here (i.e., explicit representation of urban energy consumption processes due to AC systems) require incorporation in future meteorological and climate investigations to improve weather and climate predictability. Our results demonstrate that releasing waste heat into the ambient environment exacerbates the nocturnal urban heat island and increases cooling demands.

  19. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Intake-air flow meter. 1065.225... flow meter. (a) Application. You may use an intake-air flow meter in combination with a chemical..., you may use an intake-air flow meter signal that does not give the actual value of raw exhaust, as...

  20. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Intake-air flow meter. 1065.225... flow meter. (a) Application. You may use an intake-air flow meter in combination with a chemical..., you may use an intake-air flow meter signal that does not give the actual value of raw exhaust, as...

  1. Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

    NASA Technical Reports Server (NTRS)

    Jentink, Henk W.; Bogue, Rodney K.

    2005-01-01

    Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

  2. Review of air flow measurement techniques

    SciTech Connect

    McWilliams, Jennifer

    2002-12-01

    Airflow measurement techniques are necessary to determine the most basic of indoor air quality questions: ''Is there enough fresh air to provide a healthy environment for the occupants of the building?'' This paper outlines airflow measurement techniques, but it does not make recommendations for techniques that should be used. The airflows that will be discussed are those within a room or zone, those between rooms or zones, such as through doorways (open or closed) or passive vents, those between the building and outdoors, and those through mechanical air distribution systems. Techniques that are highlighted include particle streak velocimetry, hot wire anemometry, fan pressurization (measuring flow at a given pressure), tracer gas, acoustic methods for leak size determination, the Delta Q test to determine duct leakage flows, and flow hood measurements. Because tracer gas techniques are widely used to measure airflow, this topic is broken down into sections as follows: decay, pulse injection, constant injection, constant concentration, passive sampling, and single and multiple gas measurements for multiple zones.

  3. Thermohydraulic analysis of the cooling air flow in a rack

    NASA Astrophysics Data System (ADS)

    Natusch, Andreas; Huchler, Markus

    Manned space laboratories like the US Space Station Freedom or the European COLUMBUS APM are equipped with so-called racks for subsystem and payload accommodation. An important resource is air for cooling the unit internal heat sources, the avionics air. Each unit inside the rack must be supplied with sufficient amount of air to cool down the unit to the allowable maximum temperature. In the course of the COLUMBUS Environmental Control and Life Support Subsystem (ECLSS) project, a thermohydraulic mathematical model (THMM) of a representative COLUMBUS rack was developed to analyze and optimize the distribution of avionic air inside this rack. A sensitivity and accuracy study was performed to determine the accuracy range of the calculated avionics flow rate distribution to the units. These calculations were then compared to measurement results gained in a rack airflow distribution test, which was performed with an equipped COLUMBUS subsystem rack to show the pressure distribution inside the rack. In addition to that cold flow study, the influence of the avionics air heating due to the unit dissipations on the airflow distribution and the cooling tenmperature was investigated in a detailed warm flow analysis.

  4. Microbial contamination of indoor air due to leakages from crawl space: a field study.

    PubMed

    Airaksinen, M; Pasanen, P; Kurnitski, J; Seppänen, O

    2004-02-01

    Mechanical exhaust ventilation system is typical in apartment buildings in Finland. In most buildings the base floor between the first floor apartments and crawl space is not air tight. As the apartments have lower pressure than the crawl space due to ventilation, contaminated air may flow from the crawl space to the apartments. The object of this study was to find out whether a potential air flow from crawl space has an influence on the indoor air quality. The results show that in most cases the concentration of fungal spores was clearly higher in the crawl space than inside the building. The size distribution of fungal spores depended on the fungal species. Correlation between the fungal spores in the crawl space and indoors varied with microbial species. Some species have sources inside the building, which confounds the possible relation between crawl pace and indoor concentrations. Some species, such as Acremonium, do not normally have a source indoors, but its concentration in the crawl space was elevated; our measurements showed also elevated concentrations of Acremonium in the air of the apartments. This consistent finding shows a clear linkage between fungal spores in the indoor air and crawl space. We conclude that a building with a crawl space and pressure difference over the base floor could be a potential risk for indoor air quality in the first floor apartments.

  5. Air Entrainment in a Liquid Cell due to Fiber Drawing

    NASA Astrophysics Data System (ADS)

    Simpkins, P. G.; Kuck, V. J.

    1997-11-01

    Preliminary observations of air entrainment into a liquid bath of viscous Newtonian fluid are described. The motion generated by an optical fiber moving vertically through the bath gives rise to a free surface that is cusp-like. Photomicrographs of the contact region, however, illustrate that the free surface profile becomes conical with a small included angle that is draw speed dependent. There is some evidence to suggest that tip-streaming ( Taylor, G. I. 1934 The Formation of Emulsions in Definable Fields of Flow. Proc. Roy. Soc. Lond. A146, 501-523.) footnote Sherwood, J. D. 1984 Tip Streaming from Slender Drops in a Nonlinear Extensional Flow. J. Fluid Mech. 144, 281-295. filaments of air emanate from the contact zone to give rise to minute ( 10mm) bubbles via Rayleigh-Taylor instability. Continuous operation after the onset of tip-streaming results in the creation of larger bubbles from the small ones via coalescence during recirculation in the bath. Eventually the occurrence of very large bubbles can lead to break out and the absence of any coating on the fiber.

  6. A survey of air flow models for multizone structures

    SciTech Connect

    Feustel, H.E.; Dieris, J.

    1991-03-01

    Air flow models are used to simulate the rates of incoming and outgoing air flows for a building with known leakage under given weather and shielding conditions. Additional information about the flow paths and air-mass flows inside the building can only by using multizone air flow models. In order to obtain more information on multizone air flow models, a literature review was performed in 1984. A second literature review and a questionnaire survey performed in 1989, revealed the existence of 50 multizone air flow models, all developed since 1966, two of which are still under development. All these programs use similar flow equations for crack flow but differ in the versatility to describe the full range of flow phenomena and the algorithm provided for solving the set of nonlinear equations. This literature review was found that newer models are able to describe and simulate the ventilation systems and interrelation of mechanical and natural ventilation. 27 refs., 2 figs., 1 tab.

  7. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Air flow (III mines). 57.22213 Section 57.22213... Methane in Metal and Nonmetal Mines Ventilation § 57.22213 Air flow (III mines). The quantity of air... longwall and continuous miner sections. The quantity of air across each face at a work place shall be...

  8. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Air flow (III mines). 57.22213 Section 57.22213... Methane in Metal and Nonmetal Mines Ventilation § 57.22213 Air flow (III mines). The quantity of air... longwall and continuous miner sections. The quantity of air across each face at a work place shall be at...

  9. 40 CFR 90.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Intake air flow measurement... Gaseous Exhaust Test Procedures § 90.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure...

  10. 40 CFR 90.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Intake air flow measurement... Gaseous Exhaust Test Procedures § 90.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure...

  11. 40 CFR 90.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Intake air flow measurement... Gaseous Exhaust Test Procedures § 90.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure...

  12. 40 CFR 90.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Intake air flow measurement... Gaseous Exhaust Test Procedures § 90.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure...

  13. Fatigue of LMFBR piping due to flow stratification

    SciTech Connect

    Woodward, W.S.

    1983-01-01

    Flow stratification due to reverse flow was simulated in a 1/5-scale water model of a LMFBR primary pipe loop. The stratified flow was observed to have a dynamic interface region which oscillated in a wave pattern. The behavior of the interface was characterized in terms of location, local temperature fluctuation and duration for various reverse flow conditions. A structural assessment was performed to determine the effects of stratified flow on the fatigue life of the pipe. Both the static and dynamic aspects of flow stratification were examined. The dynamic interface produces thermal striping on the inside of the pipe wall which is shown to have the most deleterious effect on the pipe wall and produce significant fatigue damage relative to a static interface.

  14. Discovery about temperature fluctuations in turbulent air flows

    NASA Astrophysics Data System (ADS)

    1985-02-01

    The law of spatial fluctuations of temperature in a turbulent flow in the atmosphere was studied. The turbulent movement of air in the atmosphere manifests itself in random changes in wind velocity and in the dispersal of smoke. If a miniature thermometer with sufficient sensitivity and speed of response were placed in a air flow, its readings would fluctuate chaotically against the background of average temperature. This is Characteristic of practically every point of the flow. The temperature field forms as a result of the mixing of the air. A method using the relation of the mean square of the difference in temperatures of two points to the distance between these points as the structural characteristic of this field was proposed. It was found that the dissipation of energy in a flow and the equalization of temperatures are connected with the breaking up of eddies in a turbulent flow into smaller ones. Their energy in turn is converted into heat due to the viscosity of the medium. The law that has been discovered makes for a much broader field of application of physical methods of analyzing atmospheric phenomena.

  15. Air pollution effects due to deregulation of the electric industry

    NASA Astrophysics Data System (ADS)

    Davoodi, Khojasteh Riaz

    ) nuclear sources until the year 2005. Each module was analyzed separately and the result from each module was transferred into the Air Quality Impact model. The model assesses the changes in electricity generation within each module due to deregulation and these changes can then be correlated to the emission of air pollutants in the United States.

  16. Combustor air flow control method for fuel cell apparatus

    DOEpatents

    Clingerman, Bruce J.; Mowery, Kenneth D.; Ripley, Eugene V.

    2001-01-01

    A method for controlling the heat output of a combustor in a fuel cell apparatus to a fuel processor where the combustor has dual air inlet streams including atmospheric air and fuel cell cathode effluent containing oxygen depleted air. In all operating modes, an enthalpy balance is provided by regulating the quantity of the air flow stream to the combustor to support fuel cell processor heat requirements. A control provides a quick fast forward change in an air valve orifice cross section in response to a calculated predetermined air flow, the molar constituents of the air stream to the combustor, the pressure drop across the air valve, and a look up table of the orifice cross sectional area and valve steps. A feedback loop fine tunes any error between the measured air flow to the combustor and the predetermined air flow.

  17. Moisture Risk in Unvented Attics Due to Air Leakage Paths

    SciTech Connect

    Prahl, D.; Shaffer, M.

    2014-11-01

    IBACOS completed an initial analysis of moisture damage potential in an unvented attic insulated with closed-cell spray polyurethane foam. To complete this analysis, the research team collected field data, used computational fluid dynamics to quantify the airflow rates through individual airflow (crack) paths, simulated hourly flow rates through the leakage paths with CONTAM software, correlated the CONTAM flow rates with indoor humidity ratios from Building Energy Optimization software, and used Warme und Feuchte instationar Pro two-dimensional modeling to determine the moisture content of the building materials surrounding the cracks. Given the number of simplifying assumptions and numerical models associated with this analysis, the results indicate that localized damage due to high moisture content of the roof sheathing is possible under very low airflow rates. Reducing the number of assumptions and approximations through field studies and laboratory experiments would be valuable to understand the real-world moisture damage potential in unvented attics.

  18. Moisture Risk in Unvented Attics Due to Air Leakage Paths

    SciTech Connect

    Prahl, D.; Shaffer, M.

    2014-11-01

    IBACOS completed an initial analysis of moisture damage potential in an unvented attic insulated with closed-cell spray polyurethane foam. To complete this analysis, the research team collected field data, used computational fluid dynamics to quantify the airflow rates through individual airflow (crack) paths, simulated hourly flow rates through the leakage paths with CONTAM software, correlated the CONTAM flow rates with indoor humidity ratios from Building Energy Optimization software, and used Wärme und Feuchte instationär Pro two-dimensional modeling to determine the moisture content of the building materials surrounding the cracks. Given the number of simplifying assumptions and numerical models associated with this analysis, the results indicate that localized damage due to high moisture content of the roof sheathing is possible under very low airflow rates. Reducing the number of assumptions and approximations through field studies and laboratory experiments would be valuable to understand the real-world moisture damage potential in unvented attics.

  19. Gating of a mechanosensitive channel due to cellular flows

    PubMed Central

    Pak, On Shun; Young, Y.-N.; Marple, Gary R.; Veerapaneni, Shravan; Stone, Howard A.

    2015-01-01

    A multiscale continuum model is constructed for a mechanosensitive (MS) channel gated by tension in a lipid bilayer membrane under stresses due to fluid flows. We illustrate that for typical physiological conditions vesicle hydrodynamics driven by a fluid flow may render the membrane tension sufficiently large to gate a MS channel open. In particular, we focus on the dynamic opening/closing of a MS channel in a vesicle membrane under a planar shear flow and a pressure-driven flow across a constriction channel. Our modeling and numerical simulation results quantify the critical flow strength or flow channel geometry for intracellular transport through a MS channel. In particular, we determine the percentage of MS channels that are open or closed as a function of the relevant measure of flow strength. The modeling and simulation results imply that for fluid flows that are physiologically relevant and realizable in microfluidic configurations stress-induced intracellular transport across the lipid membrane can be achieved by the gating of reconstituted MS channels, which can be useful for designing drug delivery in medical therapy and understanding complicated mechanotransduction. PMID:26216988

  20. Gating of a mechanosensitive channel due to cellular flows.

    PubMed

    Pak, On Shun; Young, Y-N; Marple, Gary R; Veerapaneni, Shravan; Stone, Howard A

    2015-08-11

    A multiscale continuum model is constructed for a mechanosensitive (MS) channel gated by tension in a lipid bilayer membrane under stresses due to fluid flows. We illustrate that for typical physiological conditions vesicle hydrodynamics driven by a fluid flow may render the membrane tension sufficiently large to gate a MS channel open. In particular, we focus on the dynamic opening/closing of a MS channel in a vesicle membrane under a planar shear flow and a pressure-driven flow across a constriction channel. Our modeling and numerical simulation results quantify the critical flow strength or flow channel geometry for intracellular transport through a MS channel. In particular, we determine the percentage of MS channels that are open or closed as a function of the relevant measure of flow strength. The modeling and simulation results imply that for fluid flows that are physiologically relevant and realizable in microfluidic configurations stress-induced intracellular transport across the lipid membrane can be achieved by the gating of reconstituted MS channels, which can be useful for designing drug delivery in medical therapy and understanding complicated mechanotransduction.

  1. Decentralized and Tactical Air Traffic Flow Management

    NASA Technical Reports Server (NTRS)

    Odoni, Amedeo R.; Bertsimas, Dimitris

    1997-01-01

    This project dealt with the following topics: 1. Review and description of the existing air traffic flow management system (ATFM) and identification of aspects with potential for improvement. 2. Identification and review of existing models and simulations dealing with all system segments (enroute, terminal area, ground) 3. Formulation of concepts for overall decentralization of the ATFM system, ranging from moderate decentralization to full decentralization 4. Specification of the modifications to the ATFM system required to accommodate each of the alternative concepts. 5. Identification of issues that need to be addressed with regard to: determination of the way the ATFM system would be operating; types of flow management strategies that would be used; and estimation of the effectiveness of ATFM with regard to reducing delay and re-routing costs. 6. Concept evaluation through identification of criteria and methodologies for accommodating the interests of stakeholders and of approaches to optimization of operational procedures for all segments of the ATFM system.

  2. Parametric Studies of Flow Separation using Air Injection

    NASA Technical Reports Server (NTRS)

    Zhang, Wei

    2004-01-01

    Boundary Layer separation causes the airfoil to stall and therefore imposes dramatic performance degradation on the airfoil. In recent years, flow separation control has been one of the active research areas in the field of aerodynamics due to its promising performance improvements on the lifting device. These active flow separation control techniques include steady and unsteady air injection as well as suction on the airfoil surface etc. This paper will be focusing on the steady and unsteady air injection on the airfoil. Although wind tunnel experiments revealed that the performance improvements on the airfoil using injection techniques, the details of how the key variables such as air injection slot geometry and air injection angle etc impact the effectiveness of flow separation control via air injection has not been studied. A parametric study of both steady and unsteady air injection active flow control will be the main objective for this summer. For steady injection, the key variables include the slot geometry, orientation, spacing, air injection velocity as well as the injection angle. For unsteady injection, the injection frequency will also be investigated. Key metrics such as lift coefficient, drag coefficient, total pressure loss and total injection mass will be used to measure the effectiveness of the control technique. A design of experiments using the Box-Behnken Design is set up in order to determine how each of the variables affects each of the key metrics. Design of experiment is used so that the number of experimental runs will be at minimum and still be able to predict which variables are the key contributors to the responses. The experiments will then be conducted in the 1ft by 1ft wind tunnel according to the design of experiment settings. The data obtained from the experiments will be imported into JMP, statistical software, to generate sets of response surface equations which represent the statistical empirical model for each of the metrics as

  3. Parametric Studies of Flow Separation using Air Injection

    NASA Technical Reports Server (NTRS)

    Zhang, Wei

    2004-01-01

    Boundary Layer separation causes the airfoil to stall and therefore imposes dramatic performance degradation on the airfoil. In recent years, flow separation control has been one of the active research areas in the field of aerodynamics due to its promising performance improvements on the lifting device. These active flow separation control techniques include steady and unsteady air injection as well as suction on the airfoil surface etc. This paper will be focusing on the steady and unsteady air injection on the airfoil. Although wind tunnel experiments revealed that the performance improvements on the airfoil using injection techniques, the details of how the key variables such as air injection slot geometry and air injection angle etc impact the effectiveness of flow separation control via air injection has not been studied. A parametric study of both steady and unsteady air injection active flow control will be the main objective for this summer. For steady injection, the key variables include the slot geometry, orientation, spacing, air injection velocity as well as the injection angle. For unsteady injection, the injection frequency will also be investigated. Key metrics such as lift coefficient, drag coefficient, total pressure loss and total injection mass will be used to measure the effectiveness of the control technique. A design of experiments using the Box-Behnken Design is set up in order to determine how each of the variables affects each of the key metrics. Design of experiment is used so that the number of experimental runs will be at minimum and still be able to predict which variables are the key contributors to the responses. The experiments will then be conducted in the 1ft by 1ft wind tunnel according to the design of experiment settings. The data obtained from the experiments will be imported into JMP, statistical software, to generate sets of response surface equations which represent the statistical empirical model for each of the metrics as

  4. Acoustic tomographic imaging of temperature and flow fields in air

    NASA Astrophysics Data System (ADS)

    Barth, Manuela; Raabe, Armin

    2011-03-01

    Acoustic travel-time tomography is a remote sensing technique that uses the dependence of sound speed in air on temperature and wind speed along the sound propagation path. Travel-time measurements of acoustic signals between several sound sources and receivers travelling along different paths through a measuring area give information on the spatial distribution of temperature and flow fields within the area. After a separation of the two influences, distributions of temperature and flow can be reconstructed using inverse algorithms. As a remote sensing method, one advantage of acoustic travel-time tomography is its ability to measure temperature and flow field quantities without disturbing the area under investigation due to insertion of sensors. Furthermore, the two quantities—temperature and flow velocity—can be recorded simultaneously with this measurement method. In this paper, an acoustic tomographic measurement system is introduced which is capable of resolving three-dimensional distributions of temperature and flow fields in air within a certain volume (1.3 m × 1.0 m × 1.2 m) using 16 acoustic transmitter-receiver pairs. First, algorithms for the 3D reconstruction of distributions from line-integrated measurements are presented. Moreover, a measuring apparatus is introduced which is suited for educational purposes, for demonstration of the method as well as for indoor investigations. Example measurements within a low-speed wind tunnel with different incident flow situations (e.g. behind bluff bodies) using this system are shown. Visualizations of the flow illustrate the plausibility of the tomographically reconstructed flow structures. Furthermore, alternative individual measurement methods for temperature and flow speed provide comparable results.

  5. Dynamic Flow Management Problems in Air Transportation

    NASA Technical Reports Server (NTRS)

    Patterson, Sarah Stock

    1997-01-01

    In 1995, over six hundred thousand licensed pilots flew nearly thirty-five million flights into over eighteen thousand U.S. airports, logging more than 519 billion passenger miles. Since demand for air travel has increased by more than 50% in the last decade while capacity has stagnated, congestion is a problem of undeniable practical significance. In this thesis, we will develop optimization techniques that reduce the impact of congestion on the national airspace. We start by determining the optimal release times for flights into the airspace and the optimal speed adjustment while airborne taking into account the capacitated airspace. This is called the Air Traffic Flow Management Problem (TFMP). We address the complexity, showing that it is NP-hard. We build an integer programming formulation that is quite strong as some of the proposed inequalities are facet defining for the convex hull of solutions. For practical problems, the solutions of the LP relaxation of the TFMP are very often integral. In essence, we reduce the problem to efficiently solving large scale linear programming problems. Thus, the computation times are reasonably small for large scale, practical problems involving thousands of flights. Next, we address the problem of determining how to reroute aircraft in the airspace system when faced with dynamically changing weather conditions. This is called the Air Traffic Flow Management Rerouting Problem (TFMRP) We present an integrated mathematical programming approach for the TFMRP, which utilizes several methodologies, in order to minimize delay costs. In order to address the high dimensionality, we present an aggregate model, in which we formulate the TFMRP as a multicommodity, integer, dynamic network flow problem with certain side constraints. Using Lagrangian relaxation, we generate aggregate flows that are decomposed into a collection of flight paths using a randomized rounding heuristic. This collection of paths is used in a packing integer

  6. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Intake-air flow meter. 1065.225... flow meter. (a) Application. You may use an intake-air flow meter in combination with a chemical... meter signal that does not give the actual value of raw exhaust, as long as it is linearly...

  7. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION... flow element, an ultrasonic flow meter, a subsonic venturi, a thermal-mass meter, an averaging...

  8. 40 CFR 1065.225 - Intake-air flow meter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Intake-air flow meter. 1065.225 Section 1065.225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION... flow element, an ultrasonic flow meter, a subsonic venturi, a thermal-mass meter, an averaging...

  9. Flow Enhancement due to Elastic Turbulence in Channel Flows of Shear Thinning Fluids

    NASA Astrophysics Data System (ADS)

    Bodiguel, Hugues; Beaumont, Julien; Machado, Anaïs; Martinie, Laetitia; Kellay, Hamid; Colin, Annie

    2015-01-01

    We explore the flow of highly shear thinning polymer solutions in straight geometry. The strong variations of the normal forces close to the wall give rise to an elastic instability. We evidence a periodic motion close the onset of the instability, which then evolves towards a turbulentlike flow at higher flow rates. Strikingly, we point out that this instability induces genuine drag reduction due to the homogenization of the viscosity profile by the turbulent flow.

  10. Air flow exploration of abrasive feed tube

    NASA Astrophysics Data System (ADS)

    Zhang, Shijin; Li, Xiaohong; Gu, Yilei

    2009-12-01

    An abrasive water-jet cutting process is one in which water pressure is raised to a very high pressure and forced through a very small orifice to form a very thin high speed jet beam. This thin jet beam is then directed through a chamber and then fed into a secondary nozzle, or mixing tube. During this process, a vacuum is generated in the chamber, and garnet abrasives and air are pulled into the chamber, through an abrasive feed tube, and mixes with this high speed stream of water. Because of the restrictions introduced by the abrasive feed tube geometry, a vacuum gradient is generated along the tube. Although this phenomenon has been recognized and utilized as a way to monitor nozzle condition and abrasive flowing conditions, yet, until now, conditions inside the abrasive feed line have not been completely understood. A possible reason is that conditions inside the abrasive feed line are complicated. Not only compressible flow but also multi-phase, multi-component flow has been involved in inside of abrasive feed tube. This paper explored various aspects of the vacuum creation process in both the mixing chamber and the abrasive feed tube. Based on an experimental exploration, an analytical framework is presented to allow theoretical calculations of vacuum conditions in the abrasive feed tube.

  11. Fuselage ventilation due to wind flow about a postcrash aircraft

    NASA Technical Reports Server (NTRS)

    Stuart, J. W.

    1980-01-01

    Postcrash aircraft fuselage fire development, dependent on the internal and external fluid dynamics is discussed. The natural ventilation rate, a major factor in the internal flow patterns and fire development is reviewed. The flow about the fuselage as affected by the wind and external fire is studied. An analysis was performend which estimated the rates of ventilation produced by the wind for a limited idealized environmental configuration. The simulation utilizes the empirical pressure coefficient distribution of an infinite circular cylinder near a wall with its boundary later flow to represent the atmospheric boundary layer. The resulting maximum ventilation rate for two door size openings, with varying circumferential location in a common 10 mph wind was an order of magnitude greater than the forced ventilation specified in full scale fire testing. The parameter discussed are: (1) fuselage size and shape, (2) fuselage orientation and proximity to the ground, (3) fuselage-openings size and location, (4) wind speed and direction, and (5) induced flow of the external fire plume is recommended. The fire testing should be conducted to a maximum ventilation rate at least an order of magnitude greater than the inflight air conditioning rates.

  12. Excitation of flow instabilities due to nonlinear scale invariance

    SciTech Connect

    Prasad Datta, Dhurjati; Sen, Sudip

    2014-05-15

    A novel route to instabilities and turbulence in fluid and plasma flows is presented in kinetic Vlasov-Maxwell model. New kind of flow instabilities is shown to arise due to the availability of new kinetic energy sources which are absent in conventional treatments. The present approach is based on a scale invariant nonlinear analytic formalism developed to address irregular motions on a chaotic attractor or in turbulence in a more coherent manner. We have studied two specific applications of this turbulence generating mechanism. The warm plasma Langmuir wave dispersion relation is shown to become unstable in the presence of these multifractal measures. In the second application, these multifractal measures are shown to induce naturally non-Gaussian, i.e., a stretched, Gaussian distribution and anomalous transport for tracer particles from the turbulent advection-diffusion transport equation in a Vlasov plasma flow.

  13. Optical phase distortion due to compressible flow over laser turrets

    NASA Technical Reports Server (NTRS)

    Fuhs, A. E.; Fuhs, S. E.

    1980-01-01

    Analytical models for optical phase distortion due to compressible flow over a laser turret are developed. Phase distortion is calculated for both blunt and small perturbation turrets. For the blunt turret, the Janzen-Rayleigh technique is used to determine the flow field. Phase distortions of 2.2 wavelengths at 3.8 microns are calculated for the blunt turret. For small perturbation turrets, a versatile analytical model is developed for a turret on a fuselage with circular cross section. With a two dimensional Fourier series representation of the turret, any shape can be considered. Both subsonic and supersonic flows can be calculated. Phase distortions of 1.2 wavelengths at 3.8 microns are calculated for one turret at high subsonic Mach number. In addition to being of value for laser turrets, the methods are applicable to reconnaissance aircraft using photographic equipment and cruise missiles using celestial navigation.

  14. Numerical investigation of thrust vectoring by injection of secondary air into nozzle flows

    NASA Astrophysics Data System (ADS)

    Berens, T.

    1993-11-01

    Injection of secondary air into nozzle flows is an efficient method to control the thrust vector angle of an aircraft. A numerical investigation of thrust vectoring has been carried out for hypersonic aircraft in the transonic flight regime. In this speed range, single duct asymmetrical single expansion ramp nozzles operate far off design due to large nozzle exit areas required for optimal thrust coefficients at hypersonic cruise Mach numbers, thus producing large thrust components in the downward direction. Injecting secondary air into the nozzle flow in the critical transonic flight Mach number regime can lead to favorable gross thrust vector angles and thus improved thrust efficiency in flight direction. For a hypersonic aircraft's rectangular convergent-divergent nozzle configuration with a single expansion ramp, two dimensional Euler calculations of the complete afterbody flow field were carried out in the transonic flight regime, investigating subsonic as well as supersonic injection of the aircraft's forebody boundary layer air into the nozzle flow. Subsonic flow of the injected air along the expansion ramp produces a favorable pressure distribution on the ramp and results in advantageous thrust vectors with small force components normal to the flight direction and in best thrust efficiency. The interaction between the external flow, the jet plume flow, and the secondary air flow, as well as the behavior of the thrust vector, due to pressure and temperature variations of the injected forebody boundary layer air, are discussed. Also investigated was the impact of the aircraft's angle of attack on the complete nozzle flow field.

  15. A Study on the Air flow outside Ambient Vaporizer Fin

    NASA Astrophysics Data System (ADS)

    Oh, G.; Lee, T.; Jeong, H.; Chung, H.

    2015-09-01

    In this study, we interpreted Fog's Fluid that appear in the Ambient Vaporizer and predict the point of change Air to Fog. We interpreted using Analysis working fluid was applied to LNG and Air. We predict air flow when there is chill of LNG in the air Temperature and that makes fog. Also, we interpreted based on Summer and Winter criteria in the air temperature respectively. Finally, we can check the speed of the fog when fog excreted.

  16. Redistribution of energy flow in a material due to damping.

    PubMed

    Li, Xin; Pierce, Donna M; Arnoldus, Henk F

    2011-02-01

    The field lines of energy flow of the radiation emitted by a linear dipole in free space are straight lines, running radially outward from the source. When the dipole is embedded in a medium, the field lines are curves when the imaginary part of the relative permittivity is finite. It is shown that due to the damping in the material all radiation is emitted in directions perpendicular to the dipole axis, whereas for a dipole in free space the radiation is emitted in all directions except along the dipole axis. It is also shown that some field lines in the near field form semiloops. Energy flowing along these semiloops is absorbed by the material and does not contribute to the radiative power in the far field.

  17. Intercooler cooling-air weight flow and pressure drop for minimum drag loss

    NASA Technical Reports Server (NTRS)

    Reuter, J George; Valerino, Michael F

    1944-01-01

    An analysis has been made of the drag losses in airplane flight of cross-flow plate and tubular intercoolers to determine the cooling-air weight flow and pressure drop that give a minimum drag loss for any given cooling effectiveness and, thus, a maximum power-plant net gain due to charge-air cooling. The drag losses considered in this analysis are those due to (1) the extra drag imposed on the airplane by the weight of the intercooler, its duct, and its supports and (2) the drag sustained by the cooling air in flowing through the intercooler and its duct. The investigation covers a range of conditions of altitude, airspeed, lift-drag ratio, supercharger-pressure ratio, and supercharger adiabatic efficiency. The optimum values of cooling air pressure drop and weight flow ratio are tabulated. Curves are presented to illustrate the results of the analysis.

  18. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Exhaust Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for all...

  19. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Exhaust Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for all...

  20. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Methane in Metal and Nonmetal Mines Ventilation § 57.22213 Air flow (III mines). The quantity of...

  1. Rolling resistance of articular cartilage due to interstitial fluid flow.

    PubMed

    Ateshian, G A; Wang, H

    1997-01-01

    A mechanism which may contribute to the frictional coefficient of diarthrodial joints is the rolling resistance due to hysteretic energy loss of viscoelastic cartilage resulting from interstitial fluid flow. The hypothesis of this study is that rolling resistance contributes significantly to the measured friction coefficient of articular cartilage. Due to the difficulty of testing this hypothesis experimentally, theoretical predictions of the rolling resistance are obtained using the solution for rolling contact of biphasic cylindrical cartilage layers [Ateshian and Wang]. Over a range of rolling velocities, tissue properties and dimensions, it is found that the coefficient of rolling resistance microR varies in magnitude from 10(-6) to 10(-2); thus, it is generally negligible in comparison with experimental measurements of the cartilage friction coefficient (10(-3)-10(-1)) except, possibly, when the tissue is arthritic. Hence, the hypothesis of this study is rejected on the basis of these results.

  2. Effects of filter housing and ductwork configuration on air flow uniformity inside air cleaning filter housings

    SciTech Connect

    Paul, J.D.

    1992-12-31

    Each new HEPA filter installation presents a different physical configuration based on the system requirements the available space and designer preference. Each different configuration can result in variations of air flow uniformity inside the filter housing across the filter banks. This paper will present the results of air flow uniformity testing for six different filter housing/ductwork configurations and discuss if any of the variations in air flow uniformity is attributable to the difference in the physical arrangements for the six cases.

  3. Effects of filter housing and ductwork configuration on air flow uniformity inside air cleaning filter housings

    SciTech Connect

    Paul, J.D.

    1992-01-01

    Each new HEPA filter installation presents a different physical configuration based on the system requirements the available space and designer preference. Each different configuration can result in variations of air flow uniformity inside the filter housing across the filter banks. This paper will present the results of air flow uniformity testing for six different filter housing/ductwork configurations and discuss if any of the variations in air flow uniformity is attributable to the difference in the physical arrangements for the six cases.

  4. Air conditioning system and component therefore distributing air flow from opposite directions

    NASA Technical Reports Server (NTRS)

    Obler, H. D.; Bauer, H. B. (Inventor)

    1974-01-01

    The air conditioning system comprises a plurality of separate air conditioning units coupled to a common supply duct such that air may be introduced into the supply duct in two opposite flow directions. A plurality of outlets such as registers or auxiliary or branch ducts communicate with the supply duct and valve means are disposed in the supply duct at at least some of the outlets for automatically channelling a controllable amount of air from the supply duct to the associated outlet regardless of the direction of air flow within the supply duct. The valve means comprises an automatic air volume control apparatus for distribution within the air supply duct into which air may be introduced from two opposite directions. The apparatus incorporates a freely swinging movable vane in the supply duct to automatically channel into the associated outlet only the deflected air flow which has the higher relative pressure.

  5. Particle displacement tracking applied to air flows

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1991-01-01

    Electronic Particle Image Velocimeter (PIV) techniques offer many advantages over conventional photographic PIV methods such as fast turn around times and simplified data reduction. A new all electronic PIV technique was developed which can measure high speed gas velocities. The Particle Displacement Tracking (PDT) technique employs a single cw laser, small seed particles (1 micron), and a single intensified, gated CCD array frame camera to provide a simple and fast method of obtaining two-dimensional velocity vector maps with unambiguous direction determination. Use of a single CCD camera eliminates registration difficulties encountered when multiple cameras are used to obtain velocity magnitude and direction information. An 80386 PC equipped with a large memory buffer frame-grabber board provides all of the data acquisition and data reduction operations. No array processors of other numerical processing hardware are required. Full video resolution (640x480 pixel) is maintained in the acquired images, providing high resolution video frames of the recorded particle images. The time between data acquisition to display of the velocity vector map is less than 40 sec. The new electronic PDT technique is demonstrated on an air nozzle flow with velocities less than 150 m/s.

  6. Particle displacement tracking applied to air flows

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1991-01-01

    Electronic Particle Image Velocimetric (PIV) techniques offer many advantages over conventional photographic PIV methods such as fast turn around times and simplified data reduction. A new all electronic PIV technique was developed which can measure high speed gas velocities. The Particle Displacement Tracking (PDT) technique employs a single CW laser, small seed particles (1 micron), and a single intensified, gated CCD array frame camera to provide a simple and fast method of obtaining two-dimensional velocity vector maps with unambiguous direction determination. Use of a single CCD camera eliminates registration difficulties encountered when multiple cameras are used to obtain velocity magnitude and direction information. An 80386 PC equipped with a large memory buffer frame-grabber board provides all of the data acquisition and data reduction operations. No array processors of other numerical processing hardware are required. Full video resolution (640 x 480 pixel) is maintained in the acquired images, providing high resolution video frames of the recorded particle images. The time between data acquisition to display of the velocity vector map is less than 40 sec. The new electronic PDT technique is demonstrated on an air nozzle flow with velocities less than 150 m/s.

  7. Indoor air quality. [Health hazards due to energy conservation measures

    SciTech Connect

    Hollowell, C.D.

    1981-06-01

    Rising energy prices, among other factors, have generated an incentive to reduce ventilation rates and thereby reduce the cost of heating and cooling buildings. Reduced ventilation in buildings may significantly increase exposure to indoor air pollution and perhaps have adverse effects on occupant health and comfort. Preliminary findings suggest that reduced ventilation may adversely affect indoor air quality unless appropriate control strategies are undertaken. The strategies used to control indoor air pollution depend on the specific pollutant or class of pollutants encountered, and differ somewhat depending on whether the application is to an existing building or a new building under design and construction. Whenever possible, the first course of action is prevention or reduction of pollutant emissions at the source. In most buildings, control measures involve a combination of prevention, removal, and suppression. Common sources of indoor air pollution in buildings, the specific pollutants emitted by each source, the potential health effects, and possible control techniques are discussed.

  8. Potential streamflow changes from forest decline due to air pollution

    Treesearch

    R. M. Rice; J. Lewis

    1988-01-01

    In recent years, serious die-back of forest trees has been reported in western Europe and eastern North America. One presumed cause of the forest decline is air pollution and acid deposition. Concern has been expressed that adverse hydrologic responses might occur in forested watersheds as the result of reduced evapotranspiration and increased discharge. According...

  9. Numerical Analysis for the Air Flow of Cross Flow Fan

    NASA Astrophysics Data System (ADS)

    Sakai, Hirokazu; Tokushge, Satoshi; Ishikawa, Masatoshi; Ishihara, Takuya

    There are many factors for designing the cross flow fan. Therefore, the performance of cross flow fan is not clear yet. We can analyze the transient flow of a cross flow fan using sliding mesh approach. One of the tasks using Computational Fluid Dynamics (CFD) is a way of modeling for analysis heat exchangers with cross flow fan. These tasks are very important for design. The paper has a modeling of heat exchangers and meshing the fan blades. The next tasks, we focus the ability of cross flow fan when we change the geometry of fan blades.

  10. Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

    NASA Astrophysics Data System (ADS)

    Katunská, Jana; Bullová, Iveta; Špaková, Miroslava

    2016-12-01

    The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

  11. Flow Simulation of Solid Rocket Motors. 2; Sub-Scale Air Flow Simulation of Port Flows

    NASA Technical Reports Server (NTRS)

    Yeh, Y. P.; Ramandran, N.; Smith, A. W.; Heaman, J. P.

    2000-01-01

    The injection-flow issuing from a porous medium in the cold-flow simulation of internal port flows in solid rocket motors is characterized by a spatial instability termed pseudoturbulence that produces a rather non-uniform (lumpy) injection-velocity profile. The objective of this study is to investigate the interaction between the injection- and the developing axial-flows. The findings show that this interaction generally weakens the lumpy injection profile and affects the subsequent development of the axial flow. The injection profile is found to depend on the material characteristics, and the ensuing pseudoturbulence is a function of the injection velocity, the axial position and the distance from the porous wall. The flow transition (from laminar to turbulent) of the axial-flow is accelerated in flows emerging from smaller pores primarily due to the higher pseudoturbulence produced by the smaller pores in comparison to that associated with larger pores. In flows with rather uniform injection-flow profiles (weak or no pseudoturbulence), the axial and transverse velocity components in the porous duct are found to satisfy the sine/cosine analytical solutions derived from inviscid assumptions. The transition results from the present study are compared with previous results from surveyed literature, and detailed flow development measurements are presented in terms of the blowing fraction, and characterizing Reynolds numbers.

  12. Position paper -- Tank ventilation system design air flow rates

    SciTech Connect

    Goolsby, G.K.

    1995-01-04

    The purpose of this paper is to document a project position on required ventilation system design air flow rates for the waste storage tanks currently being designed by project W-236A, the Multi-Function Waste Tank Facility (MWTF). The Title 1 design primary tank heat removal system consists of two systems: a primary tank vapor space ventilation system; and an annulus ventilation system. At the conclusion of Title 1 design, air flow rates for the primary and annulus ventilation systems were 960 scfm and 4,400 scfm, respectively, per tank. These design flow rates were capable of removing 1,250,000 Btu/hr from each tank. However, recently completed and ongoing studies have resulted in a design change to reduce the extreme case heat load to 700,000 Btu/hr. This revision of the extreme case heat load, coupled with results of scale model evaporative testing performed by WHC Thermal Hydraulics, allow for a reduction of the design air flow rates for both primary and annulus ventilation systems. Based on the preceding discussion, ICF Kaiser Hanford Co. concludes that the design should incorporate the following design air flow rates: Primary ventilation system--500 scfm maximum and Annulus ventilation system--1,100 scfm maximum. In addition, the minimum air flow rates in the primary and annulus ventilation systems will be investigated during Title 2 design. The results of the Title 2 investigation will determine the range of available temperature control using variable air flows to both ventilation systems.

  13. Laser ignition of hypersonic air-hydrogen flow

    NASA Astrophysics Data System (ADS)

    Brieschenk, S.; Kleine, H.; O'Byrne, S.

    2013-09-01

    An experimental investigation of the behaviour of laser-induced ignition in a hypersonic air-hydrogen flow is presented. A compression-ramp model with port-hole injection, fuelled with hydrogen gas, is used in the study. The experiments were conducted in the T-ADFA shock tunnel using a flow condition with a specific total enthalpy of 2.5 MJ/kg and a freestream velocity of 2 km/s. This study is the first comprehensive laser spark study in a hypersonic flow and demonstrates that laser-induced ignition at the fuel-injection site can be effective in terms of hydroxyl production. A semi-empirical method to estimate the conditions in the laser-heated gas kernel is presented in the paper. This method uses blast-wave theory together with an expansion-wave model to estimate the laser-heated gas conditions. The spatially averaged conditions found with this approach are matched to enthalpy curves generated using a standard chemical equilibrium code (NASA CEA). This allows us to account for differences that are introduced due to the idealised description of the blast wave, the isentropic expansion wave as well as thermochemical effects.

  14. Effect of air flow on tubular solar still efficiency

    PubMed Central

    2013-01-01

    Background An experimental work was reported to estimate the increase in distillate yield for a compound parabolic concentrator-concentric tubular solar still (CPC-CTSS). The CPC dramatically increases the heating of the saline water. A novel idea was proposed to study the characteristic features of CPC for desalination to produce a large quantity of distillate yield. A rectangular basin of dimension 2 m × 0.025 m × 0.02 m was fabricated of copper and was placed at the focus of the CPC. This basin is covered by two cylindrical glass tubes of length 2 m with two different diameters of 0.02 m and 0.03 m. The experimental study was operated with two modes: without and with air flow between inner and outer tubes. The rate of air flow was fixed throughout the experiment at 4.5 m/s. On the basis of performance results, the water collection rate was 1445 ml/day without air flow and 2020 ml/day with air flow and the efficiencies were 16.2% and 18.9%, respectively. Findings The experimental study was operated with two modes: without and with air flow between inner and outer tubes. The rate of air flow was fixed throughout the experiment at 4.5 m/s. Conclusions On the basis of performance results, the water collection rate was 1445 ml/day without air flow and 2020 ml/day with air flow and the efficiencies were 16.2% and 18.9%, respectively. PMID:23587020

  15. The flow feature of transverse hydrogen jet in presence of micro air jets in supersonic flow

    NASA Astrophysics Data System (ADS)

    Barzegar Gerdroodbary, M.; Amini, Younes; Ganji, D. D.; Takam, ​M. Rahimi

    2017-03-01

    Scramjet is found to be the efficient method for the space shuttle. In this paper, numerical simulation is performed to investigate the fundamental flow physics of the interaction between an array of fuel jets and multi air jets in a supersonic transverse flow. Hydrogen as a fuel is released with a global equivalence ratio of 0.5 in presence of micro air jets on a flat plate into a Mach 4 crossflow. The fuel and air are injected through streamwise-aligned flush circular portholes. The hydrogen is injected through 4 holes with 7dj space when the air is injected in the interval of the hydrogen jets. The numerical simulation is performed by using the Reynolds-averaged Navier-Stokes equations with Menter's Shear Stress Transport (SST) turbulence model. Both the number of air jets and jet-to-freestream total pressure ratio are varied in a parametric study. The interaction of the fuel and air jet in the supersonic flow present extremely complex feature of fuel and air jet. The results present various flow features depending upon the number and mass flow rate of micro air jets. These flow features were found to have significant effects on the penetration of hydrogen jets. A variation of the number of air jets, along with the jet-to-freestream total pressure ratio, induced a variety of flow structure in the downstream of the fuel jets.

  16. Secondary Flows and Sediment Transport due to Wave - Current Interaction

    NASA Astrophysics Data System (ADS)

    Ismail, Nabil; Wiegel, Robert

    2015-04-01

    Objectives: The main purpose of this study is to determine the modifications of coastal processes driven by wave-current interaction and thus to confirm hydrodynamic mechanisms associated with the interaction at river mouths and tidal inlets where anthropogenic impacts were introduced. Further, the aim of the work has been to characterize the effect of the relative strength of momentum action of waves to the opposing current on the nearshore circulation where river flow was previously effective to entrain sediments along the shoreline. Such analytical information are useful to provide guidelines for sustainable design of coastal defense structures. Methodology and Analysis: Use is made of an earlier study reported by the authors (1983) on the interaction of horizontal momentum jets and opposing shallow water waves at shorelines, and of an unpublished laboratory study (1980). The turbulent horizontal discharge was shore-normal, directed offshore, and the incident wave direction was shore-normal, travelling toward shore. Flow visualization at the smooth bottom and the water surface, velocity and water surface elevation measurements were made. Results were obtained for wave , current modifications as well as the flow pattern in the jet and the induced circulation on both sides of the jet, for a range of wave and jet characteristics. The experimental data, obtained from measurement in the 3-D laboratory basin, showed several distinct flow pattern regimes on the bottom and the water surface. The observed flow circulation regimes were found to depend on the ratio of the wave momentum action on the jet to the jet initial momentum. Based on the time and length scales of wave and current parameters and using the time average of the depth integrated conservation equations, it is found that the relative strength of the wave action on the jet could be represented by a dimensionless expression; Rsm ( ) 12ρSa20g-L0h-Cg- 2 Rsm ≈ (C0 - U) /ρ0U w (1) In the above dimensionless

  17. Ignition of hydrogen/air mixing layer in turbulent flows

    SciTech Connect

    Im, H.G.; Chen, J.H.; Law, C.K.

    1998-03-01

    Autoignition of a scalar hydrogen/air mixing layer in homogeneous turbulence is studied using direct numerical simulation. An initial counterflow of unmixed nitrogen-diluted hydrogen and heated air is perturbed by two-dimensional homogeneous turbulence. The temperature of the heated air stream is chosen to be 1,100 K which is substantially higher than the crossover temperature at which the rates of the chain branching and termination reactions become equal. Three different turbulence intensities are tested in order to assess the effect of the characteristic flow time on the ignition delay. For each condition, a simulation without heat release is also performed. The ignition delay determined with and without heat release is shown to be almost identical up to the point of ignition for all of the turbulence intensities tested, and the predicted ignition delays agree well within a consistent error band. It is also observed that the ignition kernel always occurs where hydrogen is focused, and the peak concentration of HO{sub 2} is aligned well with the scalar dissipation rate. The dependence of the ignition delay on turbulence intensity is found to be nonmonotonic. For weak to moderate turbulence the ignition is facilitated by turbulence via enhanced mixing, while for stronger turbulence, whose timescale is substantially smaller than the ignition delay, the ignition is retarded due to excessive scalar dissipation, and hence diffusive loss, at the ignition location. However, for the wide range of initial turbulence fields studied, the variation in ignition delay due to the corresponding variation in turbulence intensity appears to be quite small.

  18. 40 CFR 86.166-12 - Method for calculating emissions due to air conditioning leakage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to air conditioning leakage. 86.166-12 Section 86.166-12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY... for calculating emissions due to air conditioning leakage. This section describes procedures used...

  19. Air pollution and health risks due to vehicle traffic

    PubMed Central

    Zhang, Kai; Batterman, Stuart

    2014-01-01

    Traffic congestion increases vehicle emissions and degrades ambient air quality, and recent studies have shown excess morbidity and mortality for drivers, commuters and individuals living near major roadways. Presently, our understanding of the air pollution impacts from congestion on roads is very limited. This study demonstrates an approach to characterize risks of traffic for on- and near-road populations. Simulation modeling was used to estimate on- and near-road NO2 concentrations and health risks for freeway and arterial scenarios attributable to traffic for different traffic volumes during rush hour periods. The modeling used emission factors from two different models (Comprehensive Modal Emissions Model and Motor Vehicle Emissions Factor Model version 6.2), an empirical traffic speed–volume relationship, the California Line Source Dispersion Model, an empirical NO2–NOx relationship, estimated travel time changes during congestion, and concentration–response relationships from the literature, which give emergency doctor visits, hospital admissions and mortality attributed to NO2 exposure. An incremental analysis, which expresses the change in health risks for small increases in traffic volume, showed non-linear effects. For a freeway, “U” shaped trends of incremental risks were predicted for on-road populations, and incremental risks are flat at low traffic volumes for near-road populations. For an arterial road, incremental risks increased sharply for both on- and near-road populations as traffic increased. These patterns result from changes in emission factors, the NO2–NOx relationship, the travel delay for the on-road population, and the extended duration of rush hour for the near-road population. This study suggests that health risks from congestion are potentially significant, and that additional traffic can significantly increase risks, depending on the type of road and other factors. Further, evaluations of risk associated with congestion

  20. Air pollution and health risks due to vehicle traffic.

    PubMed

    Zhang, Kai; Batterman, Stuart

    2013-04-15

    Traffic congestion increases vehicle emissions and degrades ambient air quality, and recent studies have shown excess morbidity and mortality for drivers, commuters and individuals living near major roadways. Presently, our understanding of the air pollution impacts from congestion on roads is very limited. This study demonstrates an approach to characterize risks of traffic for on- and near-road populations. Simulation modeling was used to estimate on- and near-road NO2 concentrations and health risks for freeway and arterial scenarios attributable to traffic for different traffic volumes during rush hour periods. The modeling used emission factors from two different models (Comprehensive Modal Emissions Model and Motor Vehicle Emissions Factor Model version 6.2), an empirical traffic speed-volume relationship, the California Line Source Dispersion Model, an empirical NO2-NOx relationship, estimated travel time changes during congestion, and concentration-response relationships from the literature, which give emergency doctor visits, hospital admissions and mortality attributed to NO2 exposure. An incremental analysis, which expresses the change in health risks for small increases in traffic volume, showed non-linear effects. For a freeway, "U" shaped trends of incremental risks were predicted for on-road populations, and incremental risks are flat at low traffic volumes for near-road populations. For an arterial road, incremental risks increased sharply for both on- and near-road populations as traffic increased. These patterns result from changes in emission factors, the NO2-NOx relationship, the travel delay for the on-road population, and the extended duration of rush hour for the near-road population. This study suggests that health risks from congestion are potentially significant, and that additional traffic can significantly increase risks, depending on the type of road and other factors. Further, evaluations of risk associated with congestion must

  1. Analysis of debris-flow velocities due to superelevation

    NASA Astrophysics Data System (ADS)

    Scheidl, C.; Rickenmann, D.; McArdell, B. W.

    2012-12-01

    For debris flows the estimation of the maximum flow-velocity is considered to be essential. Often the runout or the degree of exposure of a debris-flow event can only be predicted, based on the assessment of the maximum velocity. In practice, geomorphologic traces like flood marks on banks provide important information about the flowing process of a debris flow. A possible approach to estimate maximum flow velocities is based on the vortex equation by using superelevation marks. Superelevation can be observed in bending channels, where the flow-height of the inner-curvature is lower than the flow-height of the outer-curvature, caused by the centrifugal acceleration of the flow. For the estimation of debris-flow velocities with the vortex equation, a correction factor (>1) is often introduced, accounting for the viscosity and vertical sorting of the bulk mixture. Several studies show that the correction factor may be as high as 10 and may depend on bend geometry and debris flow material properties. The objective of this work is therefore to analyze the influence of channel geometry and material properties on the vortex equation when applying to debris flows. In particular, the project aims to compare observed flow velocities from physical modeling in flume experiments with observations from debris-flow field sites. In a first step experimental investigations are done at the laboratory of the Swiss Federal Institute WSL, Birmensdorf. The flume consists of a flexible plastic half-pipe and is mounted on a wooden plane construction. At the moment two different bend radii (1.0 m and 3.0 m) with a bend angle of 60° are implemented. The total length of the flume is further covered with 40 grit silicon carbide sandpaper reflecting a constant basal friction layer. To apply for the complexity of a debris-flow process, three different material mixtures based on three different grain size distributions, were defined. Superelevation is measured by using high speed cameras

  2. Spontaneous toroidal flow generation due to negative effective momentum diffusivity

    SciTech Connect

    McMillan, Ben F.

    2015-02-15

    Spontaneous structure formation, and in particular, zonal flows, is observed in a broad range of natural and engineered systems, often arising dynamically as the saturated state of a linear instability. Flows in tokamaks are known to self-organise on small scales, but large scale toroidal flows also arise even when externally applied torques are zero. This has previously been interpreted as the result of small externally imposed breaking of a symmetry. However, we show that for large enough field line pitch, a robust spontaneous symmetry breaking occurs, leading to the generation of strong toroidal flow structures; parameters are typical of Spherical Tokamak discharges with reversed shear profiles. The short wavelength dynamics are qualitatively similar to the growth of poloidal flow structures, and toroidal flow gradients nonlinearly saturate at levels where the shearing rate is comparable to linear growth rate. On long wavelengths, we measure Prandtl numbers of around zero for these systems, in conjunction with the formation of structured toroidal flows, and we show that this is consistent with a model of momentum transport where fluxes act to reinforce small flow gradients: the effective momentum diffusivity is negative. Toroidal flow structures are largely unaffected by collisional damping, so this may allow toroidal bulk flows of order the ion thermal velocity to be maintained with zero momentum input. This phenomenon also provides a mechanism for the generation of localised meso-scale structures like transport barriers.

  3. Spontaneous toroidal flow generation due to negative effective momentum diffusivity

    NASA Astrophysics Data System (ADS)

    McMillan, Ben F.

    2015-02-01

    Spontaneous structure formation, and in particular, zonal flows, is observed in a broad range of natural and engineered systems, often arising dynamically as the saturated state of a linear instability. Flows in tokamaks are known to self-organise on small scales, but large scale toroidal flows also arise even when externally applied torques are zero. This has previously been interpreted as the result of small externally imposed breaking of a symmetry. However, we show that for large enough field line pitch, a robust spontaneous symmetry breaking occurs, leading to the generation of strong toroidal flow structures; parameters are typical of Spherical Tokamak discharges with reversed shear profiles. The short wavelength dynamics are qualitatively similar to the growth of poloidal flow structures, and toroidal flow gradients nonlinearly saturate at levels where the shearing rate is comparable to linear growth rate. On long wavelengths, we measure Prandtl numbers of around zero for these systems, in conjunction with the formation of structured toroidal flows, and we show that this is consistent with a model of momentum transport where fluxes act to reinforce small flow gradients: the effective momentum diffusivity is negative. Toroidal flow structures are largely unaffected by collisional damping, so this may allow toroidal bulk flows of order the ion thermal velocity to be maintained with zero momentum input. This phenomenon also provides a mechanism for the generation of localised meso-scale structures like transport barriers.

  4. A Study of Air Flow in an Engine Cylinder

    NASA Technical Reports Server (NTRS)

    Lee, Dana W

    1939-01-01

    A 4-stroke-cycle test engine was equipped with a glass cylinder and the air movements within it were studied while the engine was being motored. Different types of air flow were produced by using shrouded intake valves in various arrangements and by altering the shape of the intake-air passage in the cylinder head. The air movements were made visible by mixing feathers with the entering air, and high-speed motion pictures were taken of them so that the air currents might be studied in detail and their velocities measured. Motion pictures were also taken of gasoline sprays injected into the cylinder on the intake stroke. The photographs showed that: a wide variety of induced air movements could be created in the cylinder; the movements always persisted throughout the compression stroke; and the only type of movement that persisted until the end of the cycle was rotation about the cylinder axis.

  5. Centrifuge modeling of air sparging - a study of air flow through saturated porous media.

    PubMed

    Marulanda, C; Culligan, P J; Germaine, J T

    2000-02-25

    The success of air sparging as a remedial technology for treatment of contaminated aquifers is well documented. However, there is no consensus, to date, on the mechanisms that control the flow of injected air through the saturated ground. Currently, only qualitative results from laboratory experiments are available to predict the zone of influence of a sparging well. Given that the patterns of air flow through the soil will ultimately determine the efficiency of an air sparging treatment, it is important to quantify how sparged air travels through a saturated porous medium. The main objective of this research is to develop a model that describes air transport through saturated porous media. This paper presents results from an ongoing study that employs centrifuge modeling to reproduce in situ air sparging conditions. Centrifuge testing is an experimental technique that allows reduced-scale duplication, in the laboratory, of the stresses and pressure distributions encountered in the field. In situ conditions are critical in the development of actual air flow patterns. Experiments are being conducted in a transparent porous medium consisting of crushed borosilicate glass submerged in fluids of matching indices of refraction. Air is observed as it flows through the porous medium at varying gravitational accelerations. Recorded images of experiments allow the determination of flow patterns, breakthrough velocities, and plume shapes as a function of g-level and injection pressure. Results show that air flow patterns vary from fingering, at low g-levels, to pulsing at higher accelerations. Grain and pore size distribution of the porous medium do not exclusively control air flow characteristics. Injector geometry has a definite effect on breakthrough velocities and air plume shapes. Experiments have been conducted to compare the velocity of air flow through the saturated porous medium to that of air in pure liquids. Results show that the velocity of air through the medium

  6. The air-liquid flow in a microfluidic airway tree.

    PubMed

    Song, Yu; Baudoin, Michael; Manneville, Paul; Baroud, Charles N

    2011-09-01

    Microfluidic techniques are employed to investigate air-liquid flows in the lung. A network of microchannels with five generations is made and used as a simplified model of a section of the pulmonary airway tree. Liquid plugs are injected into the network and pushed by a flow of air; they divide at every bifurcation until they reach the exits of the network. A resistance, associated with the presence of one plug in a given generation, is defined to establish a linear relation between the driving pressure and the total flow rate in the network. Based on this resistance, good predictions are obtained for the flow of two successive plugs in different generations. The total flow rate of a two-plug flow is found to depend not only on the driving pressure and lengths of the plugs, but also the initial distance between them. Furthermore, long range interactions between daughters of a dividing plug are observed and discussed, particularly when the plugs are flowing through the bifurcations. These interactions lead to different flow patterns for different forcing conditions: the flow develops symmetrically when subjected to constant pressure or high flow rate forcing, while a low flow rate driving yields an asymmetric flow.

  7. Active flow control integrated diffuser (afcid) for increased energy efficiency in variable air volume systems

    NASA Astrophysics Data System (ADS)

    Van Der Schijff, Hermanus P.

    Variable air volume (VAV) air terminals are designed to save energy by reducing airflow into a given space based on occupancy and required load. Systems are typically designed to operate at peak load, however as load is reduced, performance is compromised due to inadequate throw. As a result, fans are installed to adjust for the losses, negating many of the energy savings. Additionally flow is vectored by the use of vanes, a basic passive type of flow control. An experimental investigation was performed to study the application of flow control on that of a HVAC diffuser using synthetic jets distributed evenly along the diffuser edge parallel to the flow field. The study was conducted on a 1:3 scale typical office space (150 ft2), which included a simulated scale HVAC system supplied by compressed air. Two different jet blowing ratios were investigated for system loads of 60% and 90%. The flow field was established using hot wire anemometry and Particle Image Velocimetry (PIV). This study demonstrates the effectiveness of synthetic jet based active flow control at controlling airflow, showing ability to affect throw parameters for changing flow rates within the test chamber. Vectoring of up to 20% and improvement in jet spread of 200% was demonstrated. The use of such devices has the potential to improve air quality and air distribution in building while simultaneously lowering energy demands of HVAC systems.

  8. Low power, constant-flow air pump systems

    SciTech Connect

    Polito, M.D.; Albert, B.

    1994-01-01

    A rugged, yet small and lightweight constant-flow air pump system has been designed. Flow control is achieved using a novel approach which is three times more power efficient than previous designs. The resultant savings in battery size and weight makes these pumps ideal for sampling air on balloon platforms. The pump package includes meteorological sensors and an onboard computer that stores time and sensor data and turns the constant-flow pump circuit on/off. Some applications of these systems are also presented in this report.

  9. Can Wet Rocky Granular Flows Become Debris Flows Due to Fine Sediment Production by Abrasion?

    NASA Astrophysics Data System (ADS)

    Arabnia, O.; Sklar, L. S.; Bianchi, G.; Mclaughlin, M. K.

    2015-12-01

    Debris flows are rapid mass movements in which elevated pore pressures are sustained by a viscous fluid matrix with high concentrations of fine sediments. Debris flows may form from coarse-grained wet granular flows as fine sediments are entrained from hillslope and channel material. Here we investigate whether abrasion of the rocks within a granular flow can produce sufficient fine sediments to create debris flows. To test this hypothesis experimentally, we used a set of 4 rotating drums ranging from 0.2 to 4.0 m diameter. Each drum has vanes along the boundary ensure shearing within the flow. Shear rate was varied by changing drum rotational velocity to maintain a constant Froude Number across drums. Initial runs used angular clasts of granodiorite with a tensile strength of 7.6 MPa, with well-sorted coarse particle size distributions linearly scaled with drum radius. The fluid was initially clear water, which rapidly acquired fine-grained wear products. After each 250 m tangential distance, we measured the particle size distributions, and then returned all water and sediment to the drums for subsequent runs. We calculate particle wear rates using statistics of size and mass distributions, and by fitting the Sternberg equation to the rate of mass loss from the size fraction > 2mm. Abundant fine sediments were produced in the experiments, but very little change in the median grain size was detected. This appears to be due to clast rounding, as evidenced by a decrease in the number of stable equilibrium resting points. We find that the growth in the fine sediment concentration in the fluid scales with unit drum power. This relationship can be used to estimate fine sediment production rates in the field. We explore this approach at Inyo Creek, a steep catchment in the Sierra Nevada, California. There, a significant debris flow occurred in July 2013, which originated as a coarse-grained wet granular flow. We use surveys to estimate flow depth and velocity where super

  10. Design and Implementation of Automatic Air Flow Rate Control System

    NASA Astrophysics Data System (ADS)

    Akbar, A.; Saputra, C.; Munir, M. M.; Khairurrijal

    2016-08-01

    Venturimeter is an apparatus that can be used to measure the air flow rate. In this experiment we designed a venturimeter which equipped with a valve that is used to control the air flow rate. The difference of pressure between the cross sections was measured with the differential pressure sensor GA 100-015WD which can calculate the difference of pressures from 0 to 3737.33 Pa. A 42M048C Z36 stepper motor was used to control the valve. The precision of this motor rotation is about 0.15 °. A Graphical User Interface (GUI) was developed to monitor and set the value of flow rate then an 8-bit microcontroller was used to process the control system In this experiment- the venturimeter has been examined to get the optimal parameter of controller. The results show that the controller can set the stable output air flow rate.

  11. Annular fuel and air co-flow premixer

    DOEpatents

    Stevenson, Christian Xavier; Melton, Patrick Benedict; York, William David

    2013-10-15

    Disclosed is a premixer for a combustor including an annular outer shell and an annular inner shell. The inner shell defines an inner flow channel inside of the inner shell and is located to define an outer flow channel between the outer shell and the inner shell. A fuel discharge annulus is located between the outer flow channel and the inner flow channel and is configured to inject a fuel flow into a mixing area in a direction substantially parallel to an outer airflow through the outer flow channel and an inner flow through the inner flow channel. Further disclosed are a combustor including a plurality of premixers and a method of premixing air and fuel in a combustor.

  12. Relief, nocturnal cold-air flow and air quality in Kigali, Rwanda

    NASA Astrophysics Data System (ADS)

    Henninger, Sascha

    2013-04-01

    , this result is not reassuringly, because all measured residential districts in Kigali exceeded the recommendations of the WHO, too. This suggests that the inhabitants of Kigali are exposed to enormous levels of PM10 during most of their time outdoors. So PM10 levels are increasing in areas with high rates of traffic due to the exhaust of the vehicles and the stirring up of dust from the ground, but also in fact of burning wood for cooking etc. within the residential districts. Hazardous measuring trips could be detected for nighttime measurements. Because of high temperatures, high solar radiation and a non-typical missing cloud cover the urban surface could heat up extremely, which produced a cold-air flow from the ridges and the slopes down to the "Marais" at night. This cold-air flow takes away the suspended particulate matters, which tends to accumulate within the "Marais" on the bottom of the hills, the places where most residential neighborhoods could be found and agricultural fields were used. The distinctive relief caused an accumulation within small valleys. Unfortunately, these are the favourite places of living and agriculture and this tends to high indoor-air pollution.

  13. Enlargement of postoperative aqueductal air due to elevated body temperature. Case report.

    PubMed

    Bilginer, Burçak; Ziyal, Ibrahim M; Celik, Ozgür; Ayhan, Selim; Akalan, Nejat

    2007-01-01

    Pneumocephalus has been reported after posterior fossa surgery especially with procedures performed in the sitting position. The gravitational effect is the decisive factor in the development of pneumocephalus. The entrapped air in the aqueduct may enlarge due to several factors such as elevated body temperature and may cause to deterioration in neurological status. We report a rare case of tension pneumocephalus associated with the enlargement of massive air in aqueduct due to elevated body temperature, following removal of a cervicomedullary tumor. We believe her neurological deterioration was due to the compression of the reticular formation by dilatation of postoperative air in the aqueduct due to the elevation of her body temperature.

  14. Destabilization of confined granular packings due to fluid flow

    NASA Astrophysics Data System (ADS)

    Monloubou, Martin; Sandnes, Bjørnar

    2016-04-01

    Fluid flow through granular materials can cause fluidization when fluid drag exceeds the frictional stress within the packing. Fluid driven failure of granular packings is observed in both natural and engineered settings, e.g. soil liquefaction and flowback of proppants during hydraulic fracturing operations. We study experimentally the destabilization and flow of an unconsolidated granular packing subjected to a point source fluid withdrawal using a model system consisting of a vertical Hele-Shaw cell containing a water-grain mixture. The fluid is withdrawn from the cell at a constant rate, and the emerging flow patterns are imaged in time-lapse mode. Using Particle Image Velocimetry (PIV), we show that the granular flow gets localized in a narrow channel down the center of the cell, and adopts a Gaussian velocity profile similar to those observed in dry grain flows in silos. We investigate the effects of the experimental parameters (flow rate, grain size, grain shape, fluid viscosity) on the packing destabilization, and identify the physical mechanisms responsible for the observed complex flow behaviour.

  15. 40 CFR 86.313-79 - Air flow measurement specifications; diesel engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Air flow measurement specifications... Procedures § 86.313-79 Air flow measurement specifications; diesel engines. (a) The air flow measurement method used must have a range large enough to accurately measure the air flow over the engine...

  16. 40 CFR 86.313-79 - Air flow measurement specifications; diesel engines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Air flow measurement specifications... Procedures § 86.313-79 Air flow measurement specifications; diesel engines. (a) The air flow measurement method used must have a range large enough to accurately measure the air flow over the engine...

  17. 40 CFR 86.313-79 - Air flow measurement specifications; diesel engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Air flow measurement specifications... Procedures § 86.313-79 Air flow measurement specifications; diesel engines. (a) The air flow measurement method used must have a range large enough to accurately measure the air flow over the engine...

  18. Equipment for Measuring Air Flow, Air Temperature, Relative Humidity, and Carbon Dioxide in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Jacobs, Bruce W.

    Information on equipment and techniques that school facility personnel may use to evaluate IAQ conditions are discussed. Focus is placed on the IAQ parameters of air flow, air temperature, relative humidity, as well as carbon dioxide and the equipment used to measure these factors. Reasons for measurement and for when the measurement of these…

  19. Equipment for Measuring Air Flow, Air Temperature, Relative Humidity, and Carbon Dioxide in Schools. Technical Bulletin.

    ERIC Educational Resources Information Center

    Jacobs, Bruce W.

    Information on equipment and techniques that school facility personnel may use to evaluate IAQ conditions are discussed. Focus is placed on the IAQ parameters of air flow, air temperature, relative humidity, as well as carbon dioxide and the equipment used to measure these factors. Reasons for measurement and for when the measurement of these…

  20. Flow reduction due to degassing and redissolution phenomena

    SciTech Connect

    Doughty, C.

    1995-03-01

    At the Stripa mine in Sweden, flow and transport experiments in a water-saturated fractured granite were conducted to investigate techniques for site characterization for a geologic nuclear waste repository. In the Simulated Drift Experiment, measured water inflow to an excavated drift with pressure held at 1 bar was only 1/9th the value expected based on inflow to boreholes with pressure held at 2.7 bars. Several physical and chemical mechanisms were hypothesized to be responsible for this reduction in flow. One possibility is that significant degassing of dissolved nitrogen takes place between 2.7 and 1 bars, credating a two-phase regime with an accompanying decrease in fluid mobility, resulting in a decrease in flow to the drift. To investigate this process, theoretical studies on degassing and redissolution phenomena have been carried out, beginning with an idealized model which yields a simple analytical solution, then relaxing some of the simplifying assumptions and using TOUGH2 to study the phenomena numerically. In conjunction with these theoretical studies, laboratory experiments on flow and degassing in transparent fracture replicas are being carried out, and are being used to check the modeling approach. We need to develop a fundamental understanding of degassing and redissolution in particular and two-phase flow phenomena in general for flow in fractures and fracture networks, in order to successfully model conditions around a nuclear waste repository, where long time and large space scales may preclude conclusive field experiments.

  1. Dirty air, dirty power. Mortality and health damage due to air pollution from power plants

    SciTech Connect

    Schneider, Conrad G.; Padian, M.

    2004-06-15

    The Clean Air Task Force commissioned Abt Associates, the consulting firm relied upon by US EPA to assess the health benefits of many of the agency's air regulatory programs. The report documents the asthma attacks, hospitalisations, lost work and school days, and premature deaths linked to pollution from power plants. A first report was released in 2000. The 2004 report documents for the first time the number of heart attacks and lung cancer deaths that would be caused by power plants in 2010 and 2020. It compares the premature deaths that would result under the Bush administration's air pollution plan, the existing US Clean Air Act, and a proposal sponsored by Senator Jim Jeffords to strengthen the Clean Air Act. In general it was found that the administration's plan would produce the fewest benefits. The full study is available from the EPA, abstracted separately on the Coal Abstracts database. 65 refs., 2 apps.

  2. Rotation of melting ice disks due to melt fluid flow

    NASA Astrophysics Data System (ADS)

    Dorbolo, S.; Adami, N.; Dubois, C.; Caps, H.; Vandewalle, N.; Darbois-Texier, B.

    2016-03-01

    We report experiments concerning the melting of ice disks (85 mm in diameter and 14 mm in height) at the surface of a thermalized water bath. During the melting, the ice disks undergo translational and rotational motions. In particular, the disks rotate. The rotation speed has been found to increase with the bath temperature. We investigated the flow under the bottom face of the ice disks by a particle image velocimetry technique. We find that the flow goes downwards and also rotates horizontally, so that a vertical vortex is generated under the ice disk. The proposed mechanism is the following. In the vicinity of the bottom face of the disk, the water eventually reaches the temperature of 4°C for which the water density is maximum. The 4°C water sinks and generates a downwards plume. The observed vertical vorticity results from the flow in the plume. Finally, by viscous entrainment, the horizontal rotation of the flow induces the solid rotation of the ice block. This mechanism seems generic: any vertical flow that generates a vortex will induce the rotation of a floating object.

  3. Rotation of melting ice disks due to melt fluid flow.

    PubMed

    Dorbolo, S; Adami, N; Dubois, C; Caps, H; Vandewalle, N; Darbois-Texier, B

    2016-03-01

    We report experiments concerning the melting of ice disks (85 mm in diameter and 14 mm in height) at the surface of a thermalized water bath. During the melting, the ice disks undergo translational and rotational motions. In particular, the disks rotate. The rotation speed has been found to increase with the bath temperature. We investigated the flow under the bottom face of the ice disks by a particle image velocimetry technique. We find that the flow goes downwards and also rotates horizontally, so that a vertical vortex is generated under the ice disk. The proposed mechanism is the following. In the vicinity of the bottom face of the disk, the water eventually reaches the temperature of 4 °C for which the water density is maximum. The 4 °C water sinks and generates a downwards plume. The observed vertical vorticity results from the flow in the plume. Finally, by viscous entrainment, the horizontal rotation of the flow induces the solid rotation of the ice block. This mechanism seems generic: any vertical flow that generates a vortex will induce the rotation of a floating object.

  4. Fracture flow due to hydrothermally induced quartz growth

    NASA Astrophysics Data System (ADS)

    Kling, Tobias; Schwarz, Jens-Oliver; Wendler, Frank; Enzmann, Frieder; Blum, Philipp

    2017-09-01

    Mineral precipitations are a common feature and limitation of initially open, permeable rock fractures by forming sealing structures or secondary roughness in open voids. Hence, the objective of this numerical study is the evaluation of hydraulic properties of fractures sealed by hydrothermally induced needle and compact quartz growth. Phase-field models of progressive syntaxial and idiomorphic quartz growth are implemented into a fluid flow simulation solving the Navier-Stokes equation. Flow simulations for both quartz types indicate an obvious correlation between changes in permeability, fracture properties (e.g. aperture, relative roughness and porosity) and crystal growth behavior, which also forms distinct flow paths. Thus, at lower sealing stages initial fracture permeability significantly drops down for the 'needle fracture' forming highly tortuous flow paths, while the 'compact fracture' records a considerably smaller loss. Fluid flow in both sealing fractures most widely is governed by a ;parallel plate;-like cubic law behavior. However, the 'needle fracture' also reveals flow characteristics of a porous media. A semi-theoretical equation is introduced that links geometrical (am) with hydraulically effective apertures (ah) and the relative fracture roughness. For this purpose, a geometry factor α is introduced being α = 2.5 for needle quartz and α = 1.0 for compact quartz growth. In contrast to most common ah-am-relationships this novel formulation not only reveals more precise predictions for the needle (RMSE = 1.5) and the compact fractures (RMSE = 3.2), but also exhibit a larger range of validity concerning the roughness of the 'needle' (σ/am = 0-2.4) and the 'compact fractures' (σ/am = 0-1.8).

  5. Implementation of air injection into the turbulent boundary layer of aircraft wing using external pressurized flow

    NASA Astrophysics Data System (ADS)

    Kornilov, V. I.

    2017-03-01

    The possibility of using the injection of air into the incompressible turbulent boundary layer of an axisymmetric wing through a finely perforated area provided on the wing surface was studied. The air blowing was implemented via the supply of external pressurized flow through a permeable leading edge of the wing. It is shown that, with the blowing section located on the "flat" side of the wing, only an insignificant reduction in airfoil drag could be achieved. Simultaneously, the data obtained show that there exists a possibility of raising the lift-drag ratio due to a more appropriate choice of blowing-section location in the rarefaction region of the flow.

  6. Air pollution due to traffic, air quality monitoring along three sections of National Highway N-5, Pakistan.

    PubMed

    Ali, Mahboob; Athar, Makshoof

    2008-01-01

    Transportation system has contributed significantly to the development of human civilization; on the other hand it has an enormous impact on the ambient air quality in several ways. In this paper the air and noise pollution at selected sites along three sections of National Highway was monitored. Pakistan National Highway Authority has started a Highway Improvement program for rehabilitations and maintenance of National highways to improve the traffic flows, and would ultimately improve the air quality along highways. The ambient air quality and noise level was monitored at nine different locations along these sections of highways to quantify the air pollution. The duration of monitoring at individual location was 72 h. The most of the sampling points were near the urban or village population, schools or hospitals, in order to quantify the air pollution at most affected locations along these roads. A database consisting of information regarding the source of emission, local metrology and air quality may be created to assess the profile of air quality in the area.

  7. Propulsive jet simulation with air and helium in launcher wake flows

    NASA Astrophysics Data System (ADS)

    Stephan, Sören; Radespiel, Rolf

    2016-12-01

    The influence on the turbulent wake of a generic space launcher model due to the presence of an under-expanded jet is investigated experimentally. Wake flow phenomena represent a significant source of uncertainties in the design of a space launcher. Especially critical are dynamic loads on the structure. The wake flow is investigated at supersonic (M=2.9 ) and hypersonic (M=5.9 ) flow regimes. The jet flow is simulated using air and helium as working gas. Due to the lower molar mass of helium, higher jet velocities are realized, and therefore, velocity ratios similar to space launchers can be simulated. The degree of under-expansion of the jet is moderate for the supersonic case (p_e/p_∞ ≈ 5 ) and high for the hypersonic case (p_e/p_∞ ≈ 90 ). The flow topology is described by Schlieren visualization and mean-pressure measurements. Unsteady pressure measurements are performed to describe the dynamic wake flow. The influences of the under-expanded jet and different jet velocities are reported. On the base fluctuations at a Strouhal number, around St_D ≈ 0.25 dominate for supersonic free-stream flows. With air jet, a fluctuation-level increase on the base is observed for Strouhal numbers above St_D ≈ 0.75 in hypersonic flow regime. With helium jet, distinct peaks at higher frequencies are found. This is attributed to the interactions of wake flow and jet.

  8. Propulsive jet simulation with air and helium in launcher wake flows

    NASA Astrophysics Data System (ADS)

    Stephan, Sören; Radespiel, Rolf

    2017-06-01

    The influence on the turbulent wake of a generic space launcher model due to the presence of an under-expanded jet is investigated experimentally. Wake flow phenomena represent a significant source of uncertainties in the design of a space launcher. Especially critical are dynamic loads on the structure. The wake flow is investigated at supersonic (M=2.9) and hypersonic (M=5.9) flow regimes. The jet flow is simulated using air and helium as working gas. Due to the lower molar mass of helium, higher jet velocities are realized, and therefore, velocity ratios similar to space launchers can be simulated. The degree of under-expansion of the jet is moderate for the supersonic case (p_e/p_∞ ≈ 5) and high for the hypersonic case (p_e/p_∞ ≈ 90). The flow topology is described by Schlieren visualization and mean-pressure measurements. Unsteady pressure measurements are performed to describe the dynamic wake flow. The influences of the under-expanded jet and different jet velocities are reported. On the base fluctuations at a Strouhal number, around St_D ≈ 0.25 dominate for supersonic free-stream flows. With air jet, a fluctuation-level increase on the base is observed for Strouhal numbers above St_D ≈ 0.75 in hypersonic flow regime. With helium jet, distinct peaks at higher frequencies are found. This is attributed to the interactions of wake flow and jet.

  9. Optical Air Flow Measurements in Flight

    NASA Technical Reports Server (NTRS)

    Bogue, Rodney K.; Jentink, Henk W.

    2004-01-01

    This document has been written to assist the flight-test engineer and researcher in using optical flow measurements in flight applications. The emphasis is on describing tradeoffs in system design to provide desired measurement performance as currently understood. Optical system components are discussed with examples that illustrate the issues. The document concludes with descriptions of optical measurement systems designed for a variety of applications including aeronautics research, airspeed measurement, and turbulence hazard detection. Theoretical discussion is minimized, but numerous references are provided to supply ample opportunity for the reader to understand the theoretical underpinning of optical concepts.

  10. Intraventricular flow alterations due to dyssynchronous wall motion

    NASA Astrophysics Data System (ADS)

    Pope, Audrey M.; Lai, Hong Kuan; Samaee, Milad; Santhanakrishnan, Arvind

    2015-11-01

    Roughly 30% of patients with systolic heart failure suffer from left ventricular dyssynchrony (LVD), in which mechanical discoordination of the ventricle walls leads to poor hemodynamics and suboptimal cardiac function. There is currently no clear mechanistic understanding of how abnormalities in septal-lateral (SL) wall motion affects left ventricle (LV) function, which is needed to improve the treatment of LVD using cardiac resynchronization therapy. We use an experimental flow phantom with an LV physical model to study mechanistic effects of SL wall motion delay on LV function. To simulate mechanical LVD, two rigid shafts were coupled to two segments (apical and mid sections) along the septal wall of the LV model. Flow through the LV model was driven using a piston pump, and stepper motors coupled to the above shafts were used to locally perturb the septal wall segments relative to the pump motion. 2D PIV was used to examine the intraventricular flow through the LV physical model. Alterations to SL delay results in a reduction in the kinetic energy (KE) of the flow field compared to synchronous SL motion. The effect of varying SL motion delay from 0% (synchronous) to 100% (out-of-phase) on KE and viscous dissipation will be presented. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

  11. Identify temporal trend of air temperature and its impact on forest stream flow in Lower Mississippi River Alluvial Valley using wavelet analysis

    Treesearch

    Ying Ouyang; Prem B. Parajuli; Yide Li; Theodor D. Leininger; Gary Feng

    2017-01-01

    Characterization of stream flow is essential to water resource management, water supply planning, environmental protection, and ecological restoration; while air temperature variation due to climate change can exacerbate stream flow and add instability to the flow. In this study, the wavelet analysis technique was employed to identify temporal trend of air temperature...

  12. Airway blood flow response to dry air hyperventilation in sheep

    SciTech Connect

    Parsons, G.H.; Baile, E.M.; Pare, P.D.

    1986-03-01

    Airway blood flow (Qaw) may be important in conditioning inspired air. To determine the effect of eucapneic dry air hyperventilation (hv) on Qaw in sheep the authors studied 7 anesthetized open-chest sheep after 25 min. of warm dry air hv. During each period of hv the authors have recorded vascular pressures, cardiac output (CO), and tracheal mucosal and inspired air temperature. Using a modification of the reference flow technique radiolabelled microspheres were injected into the left atrium to make separate measurements after humid air and dry air hv. In 4 animals a snare around the left main pulmonary artery was used following microsphere injection to prevent recirculation (entry into L lung of microspheres from the pulmonary artery). Qaw to the trachea and L lung as measured and Qaw for the R lung was estimated. After the final injection the sheep were killed and bronchi (Br) and lungs removed. Qaw (trachea plus L lung plus R lung) in 4 sheep increased from a mean of 30.8 to 67.0 ml/min. Airway mucosal temp. decreased from 39/sup 0/ to 33/sup 0/C. The authors conclude that dry air hv cools airway mucosa and increases Qaw in sheep.

  13. Flow sensitive actuators for micro-air vehicles

    NASA Astrophysics Data System (ADS)

    Kumar, V.; Hays, M.; Fernandez, E.; Oates, W.; Alvi, F. S.

    2011-10-01

    A macrofiber piezoelectric composite has been developed for boundary layer management of micro-air vehicles (MAVs). Specifically, a piezoelectric composite that is capable of self-sensing and controlling flow has been modeled, designed, fabricated, and tested in wind tunnel studies to quantify performance characteristics, such as the velocity field response to actuation, which is relevant for actively managing boundary layers (laminar and transition flow control). A nonlinear piezoelectric plate model was utilized to design the active structure for flow control. The dynamic properties of the piezoelectric composite actuator were also evaluated in situ during wind tunnel experiments to quantify sensing performance. Results based on velocity field measurements and unsteady pressure measurements show that these piezoelectric macrofiber composites can sense the state of flow above the surface and provide sufficient control authority to manipulate the flow conditions for transition from laminar to turbulent flow.

  14. Edge Vortex Flow Due to Inhomogeneous Ion Concentration

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2017-04-01

    The ion distribution of an open parallel electrode system is not known even though it is often used to measure the electrical characteristics of an electrolyte. Thus, for an open electrode system, we perform a non-steady direct multiphysics simulation based on the coupled Poisson-Nernst-Planck and Stokes equations and find that inhomogeneous ion concentrations at edges cause vortex flows and suppress the anomalous increase in the ion concentration near the electrodes. A surprising aspect of our findings is that the large vortex flows at the edges approximately maintain the ion-conserving condition, and thus the ion distribution of an open electrode system can be approximated by the solution of a closed electrode system that considers the ion-conserving condition rather than the Gouy-Chapman solution, which neglects the ion-conserving condition. We believe that our findings make a significant contribution to the understanding of surface science.

  15. Submicron flow of polymer solutions: slippage reduction due to confinement.

    PubMed

    Cuenca, Amandine; Bodiguel, Hugues

    2013-03-08

    Pressure-driven flows of high molecular weight polyacrylamide solutions are examined in nanoslits using fluorescence photobleaching. The effective viscosity of polymer solutions decreases when the channel height decreases below the micron scale. In addition, the apparent slippage of the solutions is characterized macroscopically on similar surfaces. Though slippage can explain qualitatively the effective viscosity reduction, a quantitative comparison shows that the slip length is greatly reduced below the micron scale. This result indicates that chain migration is suppressed in confined geometries.

  16. Evolutionary Concepts for Decentralized Air Traffic Flow Management

    NASA Technical Reports Server (NTRS)

    Adams, Milton; Kolitz, Stephan; Milner, Joseph; Odoni, Amedeo

    1997-01-01

    Alternative concepts for modifying the policies and procedures under which the air traffic flow management system operates are described, and an approach to the evaluation of those concepts is discussed. Here, air traffic flow management includes all activities related to the management of the flow of aircraft and related system resources from 'block to block.' The alternative concepts represent stages in the evolution from the current system, in which air traffic management decision making is largely centralized within the FAA, to a more decentralized approach wherein the airlines and other airspace users collaborate in air traffic management decision making with the FAA. The emphasis in the discussion is on a viable medium-term partially decentralized scenario representing a phase of this evolution that is consistent with the decision-making approaches embodied in proposed Free Flight concepts for air traffic management. System-level metrics for analyzing and evaluating the various alternatives are defined, and a simulation testbed developed to generate values for those metrics is described. The fundamental issue of modeling airline behavior in decentralized environments is also raised, and an example of such a model, which deals with the preservation of flight bank integrity in hub airports, is presented.

  17. Interrelationships of petiolar air canal architecture, water depth, and convective air flow in Nymphaea odorata (Nymphaeaceae).

    PubMed

    Richards, Jennifer H; Kuhn, David N; Bishop, Kristin

    2012-12-01

    Nymphaea odorata grows in water up to 2 m deep, producing fewer larger leaves in deeper water. This species has a convective flow system that moves gases from younger leaves through submerged parts to older leaves, aerating submerged parts. Petiolar air canals are the convective flow pathways. This study describes the structure of these canals, how this structure varies with water depth, and models how convective flow varies with depth. • Nymphaea odorata plants were grown at water depths from 30 to 90 cm. Lamina area, petiolar cross-sectional area, and number and area of air canals were measured. Field-collected leaves and leaves from juvenile plants were analyzed similarly. Using these data and data from the literature, we modeled how convective flow changes with water depth. • Petioles of N. odorata produce two central pairs of air canals; additional pairs are added peripherally, and succeeding pairs are smaller. The first three pairs account for 96% of air canal area. Air canals form 24% of petiolar cross-sectional area. Petiolar and air canal cross-sectional areas increase with water depth. Petiolar area scales with lamina area, but the slope of this relationship is lower in 90 cm water than at shallower depths. In our model, the rate of convective flow varied with depth and with the balance of influx to efflux leaves. • Air canals in N. odorata petioles increase in size and number in deeper water but at a decreasing amount in relation to lamina area. Convective flow also depends on the number of influx to efflux laminae.

  18. Split-flow regeneration in absorptive air separation

    DOEpatents

    Weimer, Robert F.

    1987-01-01

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs.

  19. Air Flow Detection in Crude Oil by Infrared Light

    PubMed Central

    Dutra, Guilherme; Martelli, Cicero; Da Silva, Marco José; Patyk, Rodolfo L.; Morales, Rigoberto E. M.

    2017-01-01

    In this paper, we used infrared light in the range of 8–12 μm to develop and test an optical imaging system to detect air bubbles flowing in oil. The system basically comprises a broadband light source and a 31 × 32 thermopile array to generate images. To analyze the effects related to light absorption, reflection, and refraction on air-oil boundaries, a numerical model was developed and the predominance of the refraction instead of the absorption in bubbles with diameters below a certain critical value was observed. The IR region of the electromagnetic spectrum has both optical and thermic behavior. To understand the limits of each effect on the oil flow imaging, a study of the influence of temperature variation on the petroleum optical detection was performed. The developed optical imaging system allowed the detection of air flow in static oil and in oil-air two-phase flow. With the presented system, it was possible to achieve images through up to 12 mm of oil volumes, but this may be enhanced by the use of optimized IR sources and detectors. PMID:28587185

  20. Air Flow Detection in Crude Oil by Infrared Light.

    PubMed

    Dutra, Guilherme; Martelli, Cicero; Da Silva, Marco José; Patyk, Rodolfo L; Morales, Rigoberto E M

    2017-06-03

    In this paper, we used infrared light in the range of 8-12 μm to develop and test an optical imaging system to detect air bubbles flowing in oil. The system basically comprises a broadband light source and a 31 × 32 thermopile array to generate images. To analyze the effects related to light absorption, reflection, and refraction on air-oil boundaries, a numerical model was developed and the predominance of the refraction instead of the absorption in bubbles with diameters below a certain critical value was observed. The IR region of the electromagnetic spectrum has both optical and thermic behavior. To understand the limits of each effect on the oil flow imaging, a study of the influence of temperature variation on the petroleum optical detection was performed. The developed optical imaging system allowed the detection of air flow in static oil and in oil-air two-phase flow. With the presented system, it was possible to achieve images through up to 12 mm of oil volumes, but this may be enhanced by the use of optimized IR sources and detectors.

  1. The Wells turbine in an oscillating air flow

    SciTech Connect

    Raghunathan, S.; Ombaka,

    1984-08-01

    An experimental study of the performance of a 0.2 m diameter Wells self rectifying air turbine with NACA 0021 blades is presented. Experiments were conducted in an oscillating flowrig. The effects of Reynolds number and Strouhal number on the performance of the turbine were investigated. Finally comparison between the results with the predictions from uni-directional flow tests are made.

  2. 30 CFR 57.22213 - Air flow (III mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Air flow (III mines). 57.22213 Section 57.22213 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards for...

  3. Split-flow regeneration in absorptive air separation

    DOEpatents

    Weimer, R.F.

    1987-11-24

    A chemical absorptive separation of air in multiple stage of absorption and desorption is performed with partial recycle of absorbent between stages of desorption necessary to match equilibrium conditions in the various stages of absorption. This allows reduced absorbent flow, reduced energy demand and reduced capital costs. 4 figs.

  4. Elliptic flow in small systems due to elliptic gluon distributions?

    NASA Astrophysics Data System (ADS)

    Hagiwara, Yoshikazu; Hatta, Yoshitaka; Xiao, Bo-Wen; Yuan, Feng

    2017-08-01

    We investigate the contributions from the so-called elliptic gluon Wigner distributions to the rapidity and azimuthal correlations of particles produced in high energy pp and pA collisions by applying the double parton scattering mechanism. We compute the 'elliptic flow' parameter v2 as a function of the transverse momentum and rapidity, and find qualitative agreement with experimental observations. This shall encourage further developments with more rigorous studies of the elliptic gluon distributions and their applications in hard scattering processes in pp and pA collisions.

  5. Changes in thickness of magnetized composites due to current flow

    NASA Astrophysics Data System (ADS)

    Bednarek, S.

    1998-02-01

    The pinch magnitude in monolithic metal conductors and ferromagnetics was estimated in this paper. The conditions for the material were formulated so that the pinch which occurs in it could reach the magnitude useful for applications. The way of production of a special composite with a laminar structure was described. The composite consists of sheets of copper foil separating the layers of the elastic ferromagnet which was made by the dispersion of hard magnetic particles in silicon. Using a measuring system containing a Michelson interferometer, measurements of changes were made in the thickness of the produced composite samples during the electric current flow. The obtained results were discussed.

  6. Coronary artery diameter variations due to pulse-flow propagation

    NASA Astrophysics Data System (ADS)

    Slump, Cornelis H.; Winkelman, Marco; Rutgers, Remke; Storm, Corstiaan J.; van Benthem, Ad C.

    1997-05-01

    Information about local diameter variations as a response to the pulse flow in the human coronary arteries may indicate the development of atherosclerosis before this can be seen as a stenosis on coronary arteries may indicate the development of atherosclerosis before this can be seen as a stenosis on coronary angiograms. This paper describes the design of an image processing tool to measure this diameter variation from a sequence of digital coronary angiograms. If a blood vessel responds less elastically to the pulse flow, this may be an indication of atherosclerosis in an early stage. We have developed an image analysis and processing algorithm which is able after vessel segment selection by the user, to calculate automatically the vessel diameter variations from a standard sequence of digital angiograms. Several problems are treated. The periodic motion of the vessel segment in the consecutive frames is taken into account by tracking the vessel segment using a 2D logarithmic search to find the minimum in the mean absolute distance. A robust artery tracing algorithm has been implemented using graph searching techniques. The local diameter is determined by first resampling the image perpendicular to the found trace and afterwards performing edge detection using the Laplacian operator. This is repeated for all frames to show the local diameter variation of the artery segment as a function of time.

  7. Effect of air pollution on peak expiratory flow rate variability.

    PubMed

    Singh, Virendra; Khandelwal, Rakesh; Gupta, A B

    2003-02-01

    Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects.

  8. Dynamic stochastic optimization models for air traffic flow management

    NASA Astrophysics Data System (ADS)

    Mukherjee, Avijit

    This dissertation presents dynamic stochastic optimization models for Air Traffic Flow Management (ATFM) that enables decisions to adapt to new information on evolving capacities of National Airspace System (NAS) resources. Uncertainty is represented by a set of capacity scenarios, each depicting a particular time-varying capacity profile of NAS resources. We use the concept of a scenario tree in which multiple scenarios are possible initially. Scenarios are eliminated as possibilities in a succession of branching points, until the specific scenario that will be realized on a particular day is known. Thus the scenario tree branching provides updated information on evolving scenarios, and allows ATFM decisions to be re-addressed and revised. First, we propose a dynamic stochastic model for a single airport ground holding problem (SAGHP) that can be used for planning Ground Delay Programs (GDPs) when there is uncertainty about future airport arrival capacities. Ground delays of non-departed flights can be revised based on updated information from scenario tree branching. The problem is formulated so that a wide range of objective functions, including non-linear delay cost functions and functions that reflect equity concerns can be optimized. Furthermore, the model improves on existing practice by ensuring efficient use of available capacity without necessarily exempting long-haul flights. Following this, we present a methodology and optimization models that can be used for decentralized decision making by individual airlines in the GDP planning process, using the solutions from the stochastic dynamic SAGHP. Airlines are allowed to perform cancellations, and re-allocate slots to remaining flights by substitutions. We also present an optimization model that can be used by the FAA, after the airlines perform cancellation and substitutions, to re-utilize vacant arrival slots that are created due to cancellations. Finally, we present three stochastic integer programming

  9. Characteristics of inhomogeneous jets in confined swirling air flows

    NASA Astrophysics Data System (ADS)

    So, R. M. C.; Ahmed, S. A.

    1984-04-01

    An experimental program to study the characteristics of inhomogeneous jets in confined swirling flows to obtain detailed and accurate data for the evaluation and improvement of turbulent transport modeling for combustor flows is discussed. The work was also motivated by the need to investigate and quantify the influence of confinement and swirl on the characteristics of inhomogeneous jets. The flow facility was constructed in a simple way which allows easy interchange of different swirlers and the freedom to vary the jet Reynolds number. The velocity measurements were taken with a one color, one component DISA Model 55L laser-Doppler anemometer employing the forward scatter mode. Standard statistical methods are used to evaluate the various moments of the signals to give the flow characteristics. The present work was directed at the understanding of the velocity field. Therefore, only velocity and turbulence data of the axial and circumferential components are reported for inhomogeneous jets in confined swirling air flows.

  10. Radiative flow due to stretchable rotating disk with variable thickness

    NASA Astrophysics Data System (ADS)

    Hayat, Tasawar; Qayyum, Sumaira; Imtiaz, Maria; Alsaedi, Ahmed

    Present article concerns with MHD flow of viscous fluid by a rotating disk with variable thickness. Heat transfer is examined in the presence of thermal radiation. Boundary layer approximation is applied to the partial differential equations. Governing equations are then transformed into ordinary differential equations by utilizing Von Karman transformations. Impact of physical parameters on velocity, temperature, skin friction coefficient and Nusselt number is presented and examined. It is observed that with an increase in disk thickness and stretching parameter the radial and axial velocities are enhanced. Prandtl number and radiation parameter have opposite behavior for temperature field. Skin friction decays for larger disk thickness index. Magnitude of Nusselt number enhances for larger Prandtl number.

  11. Onset of collective flow due to Weibel instabilities

    NASA Astrophysics Data System (ADS)

    Randrup, Jorgen; Mrówczyński, Stanisław

    2008-10-01

    Since the local momentum density is highly anisotropic at the early stage of an ultra-relativistic nuclear collision, it is expected that Weibel instabilities will generate color currents with a characteristic (preferentially transverse) wave vector. As demonstrated first by Amp'ere, different currents repel and in the SU(3) plasma there is therefore a net tendency for the Weibel currents to experience a mutual repulsion. This feature is phenomenologically important since the associated increase of the pressure provides a mechanism for the early development of collective flow. For the purpose of establishing a framework for examining this effect, we have extended our earlier work to encompass the evolving correlation function for the local momentum density. Starting from the fluctuations in a free gas of gluons, quarks and anti-quarks, we treat the self-consistent feed-back of the amplified chromodynamic fields on the phase-space densities.

  12. Soret effect due to opposing flow in square porous annulus

    NASA Astrophysics Data System (ADS)

    Al-Rashed, Abdullah A. A. A.; Athani, Abdulgaphur; Khaleed, H. M. T.

    2016-06-01

    The present work is undertaken to investigate the behavior of opposing flow in porous medium under the influence of Soret effect in a square porous annulus. The boundary conditions are such that the outer walls of annulus are maintained at higher temperature and concentration as compared to inner walls. This heat and mass transfer phenomenon is governed by three partial differential equations. The differential equations are converted into a matrix form of equations by the application of finite element method and then solved using iterative algorithm. The results are presented in terms of isotherms, iso-concentration and streamlines indicating the thermal energy, concentration and fluid velocity inside the porous medium under applied boundary conditions. It found that the maximum value of stream function in porous medium decreases with decrease in buoyancy ratio.

  13. Connecting Surface Planting with Subsurface Erosion Due to Groundwater Flow

    NASA Astrophysics Data System (ADS)

    Reardon, M.; Curran, J. C.

    2014-12-01

    Bank erosion and failure is a major contributor of fine sediment to streams and rivers, and can be driven by subsurface flow. In restoration projects, vegetation is often planted on banks to reduce erosion and stabilize the banks. However, the relationship between subsurface flow, erosion and vegetation remains somewhat speculative. A comparative study quantified the effect of surface planting on subsurface erosion and soil strength. Six 32-gallon containers were layered with a sandy loam overlying a highly conductive sand layer and a confining clay. Three treatments were applied in pairs: switchgrass (Panicum virgatum L.), sod (turf-type tall fescue and Kentucky bluegrass mix), and no vegetation. After a vegetation establishment period, the 2, 10, and 100 year rainfalls were simulated. Samples collected from ports in the containers were analyzed for subsurface drainage volume and suspended sediment concentration. After all rainfall simulations, a sediment core was taken from each container to measure shear strength and root density. Results indicate the relative benefits of vegetative planting to reduce subsurface erosion during storms and enhance soil strength. Switchgrass reduced the total amount of sediment removed from containers during all three storms when compared to the sod and during the 10 and 100 year storms when compared to the bare ground. Results from the volume analysis were more variable. Switchgrass retained the greatest volume of water from the 100 year storm event, but also released the largest fraction of water in the 2 and 10 year storms. Both sod and switchgrass planting considerably increased the time required for the soil samples to fail despite reducing the shear stress at failure. Where switchgrass grew long, woody roots, the sod developed a dense mat of interconnected thin roots. We suspect the different root patterns between sod and switchgrass to be a dominant factor in the response of the different containers.

  14. Impact of hydrotherapy on skin blood flow: How much is due to moisture and how much is due to heat?

    PubMed

    Petrofsky, Jerrold; Gunda, Shashi; Raju, Chinna; Bains, Gurinder S; Bogseth, Michael C; Focil, Nicholas; Sirichotiratana, Melissa; Hashemi, Vahideh; Vallabhaneni, Pratima; Kim, Yumi; Madani, Piyush; Coords, Heather; McClurg, Maureen; Lohman, Everett

    2010-02-01

    Hydrotherapy and whirlpool are used to increase skin blood flow and warm tissue. However, recent evidence seems to show that part of the increase in skin blood flow is not due to the warmth itself but due to the moisture content of the heat. Therefore, two series of experiments were accomplished on 10 subjects with an average age of 24.2 +/- 9.7 years and free of diabetes and cardiovascular disease. Subjects sat in a 37 degrees C hydrotherapy pool under two conditions: one in which a thin membrane protecting their skin from moisture while their arm was submerged in water and the second where their arm was allowed to be exposed to the water for 15 minutes. During this period of time, skin and body temperature were measured as well as skin blood flow by a Laser Doppler Imager. The results of the experiments showed that the vapor barrier blocked any change in skin moisture content during submersion in water, and while skin temperature was the same as during exposure to the water, the blood flow with the arm exposed to water increased from 101.1 +/- 10.4 flux to 224.9 +/- 18.2 flux, whereas blood flow increased to only 118.7 +/- 11.4 flux if the moisture of the water was blocked. Thus, a substantial portion of the increase in skin blood flow associated with warm water therapy is probably associated with moisturizing of the skin rather than the heat itself.

  15. Flow over a Modern Ram-Air Parachute Canopy

    NASA Astrophysics Data System (ADS)

    Mohammadi, Mohammad; Johari, Hamid

    2010-11-01

    The flow field on the central section of a modern ram-air parachute canopy was examined numerically using a finite-volume flow solver coupled with the one equation Spalart-Allmaras turbulence model. Ram-air parachutes are used for guided airdrop applications, and the canopy resembles a wing with an open leading edge for inflation. The canopy surfaces were assumed to be impermeable and rigid. The flow field consisted of a vortex inside the leading edge opening which effectively closed off the canopy and diverted the flow around the leading edge. The flow experienced a rather bluff leading edge in contrast to the smooth leading of an airfoil, leading to a separation bubble on the lower lip of the canopy. The flow inside the canopy was stagnant beyond the halfway point. The section lift coefficient increased linearly with the angle of attack up to 8.5 and the lift curve slope was about 8% smaller than the baseline airfoil. The leading edge opening had a major effect on the drag prior to stall; the drag is at least twice the baseline airfoil drag. The minimum drag of the section occurs over the angle of attack range of 3 -- 7 .

  16. Modelling of impaired cerebral blood flow due to gaseous emboli

    NASA Astrophysics Data System (ADS)

    Hague, J. P.; Banahan, C.; Chung, E. M. L.

    2013-07-01

    Bubbles introduced to the arterial circulation during invasive medical procedures can have devastating consequences for brain function but their effects are currently difficult to quantify. Here we present a Monte Carlo simulation investigating the impact of gas bubbles on cerebral blood flow. For the first time, this model includes realistic adhesion forces, bubble deformation, fluid dynamical considerations, and bubble dissolution. This allows investigation of the effects of buoyancy, solubility, and blood pressure on embolus clearance. Our results illustrate that blockages depend on several factors, including the number and size distribution of incident emboli, dissolution time and blood pressure. We found it essential to model the deformation of bubbles to avoid overestimation of arterial obstruction. Incorporation of buoyancy effects within our model slightly reduced the overall level of obstruction but did not decrease embolus clearance times. We found that higher blood pressures generate lower levels of obstruction and improve embolus clearance. Finally, we demonstrate the effects of gas solubility and discuss potential clinical applications of the model.

  17. Dynamics due to combined buoyancy- and Marangoni-driven convective flows around autocatalytic fronts.

    PubMed

    Budroni, M A; Rongy, L; De Wit, A

    2012-11-14

    A reaction-diffusion-convection (RDC) model is introduced to analyze convective dynamics around horizontally traveling fronts due to combined buoyancy- and surface tension-driven flows in vertical solution layers open to the air. This isothermal model provides a means for a comparative study of the two effects via tuning two key parameters: the solutal Rayleigh number Ra, which rules the buoyancy influence, and the solutal Marangoni number Ma governing the intensity of surface effects at the interface between the reacting solution and air. The autocatalytic front dynamics is probed by varying the relative importance of Ra and Ma and the resulting RDC patterns are quantitatively characterized through the analysis of the front mixing length and the topology of the velocity field. Steady asymptotic regimes are found when the bulk and the surface contributions to fluid motions act cooperatively i.e. when Ra and Ma have the same sign. Complex dynamics may arise when these numbers are of opposite signs and the two effects thus compete in an antagonistic configuration. Typically, spatiotemporal oscillations are observed as the control parameters are set in the region (Ra < 0, Ma > 0). Periodic behaviour develops here even in the absence of any double-diffusive interplay, which in previous literature was identified as a possible source of complexity.

  18. Numerical study of cross flow fan performance in an indoor air conditioning unit

    NASA Astrophysics Data System (ADS)

    Yet, New Mei; Raghavan, Vijay R.; Chinc, W. M.

    2012-06-01

    The cross flow fan is a unique type of turbo machinery where the air stream flows transversely across the impeller, passing the blades twice. Due to its complex geometry, and highly turbulent and unsteady air-flow, a numerical method is used in this work to conduct the characterization study on the performance of a cross flow fan. A 2D cross-sectional model of a typical indoor air conditioning unit has been chosen for the simulation instead of a three dimensional 3D model due to the highly complex geometry of the fan. The simplified 2D model has been validated with experiments where it is found that the RMS error between the simulation and experimental results is less than 7%. The important parameters that affect the cross flow fan performance, i.e. the internal and external blade angles, the blade thickness, and the casing design, are analyzed in this study. The formation of an eccentric vortex is observed within the impeller.

  19. Air Flow and Pressure Drop Measurements Across Porous Oxides

    NASA Technical Reports Server (NTRS)

    Fox, Dennis S.; Cuy, Michael D.; Werner, Roger A.

    2008-01-01

    This report summarizes the results of air flow tests across eight porous, open cell ceramic oxide samples. During ceramic specimen processing, the porosity was formed using the sacrificial template technique, with two different sizes of polystyrene beads used for the template. The samples were initially supplied with thicknesses ranging from 0.14 to 0.20 in. (0.35 to 0.50 cm) and nonuniform backside morphology (some areas dense, some porous). Samples were therefore ground to a thickness of 0.12 to 0.14 in. (0.30 to 0.35 cm) using dry 120 grit SiC paper. Pressure drop versus air flow is reported. Comparisons of samples with thickness variations are made, as are pressure drop estimates. As the density of the ceramic material increases the maximum corrected flow decreases rapidly. Future sample sets should be supplied with samples of similar thickness and having uniform surface morphology. This would allow a more consistent determination of air flow versus processing parameters and the resulting porosity size and distribution.

  20. Galaxy bimodality due to cold flows and shock heating

    NASA Astrophysics Data System (ADS)

    Dekel, Avishai; Birnboim, Yuval

    2006-05-01

    We address the origin of the robust bimodality observed in galaxy properties about a characteristic stellar mass ~3 × 1010Msolar. Less massive galaxies tend to be ungrouped blue star forming discs, while more massive galaxies are typically grouped red old-star spheroids. Colour-magnitude data show a gap between the red and blue sequences, extremely red luminous galaxies already at z~ 1, a truncation of today's blue sequence above L*, and massive starbursts at z~ 2-4. We propose that these features are driven by the thermal properties of the inflowing gas and their interplay with the clustering and feedback processes, all functions of the dark matter halo mass and associated with a similar characteristic scale. In haloes below a critical shock-heating mass Mshock<~ 1012Msolar, discs are built by cold streams, not heated by a virial shock, yielding efficient early star formation. It is regulated by supernova feedback into a long sequence of bursts in blue galaxies constrained to a `fundamental line'. Cold streams penetrating through hot media in M>=Mshock haloes preferentially at z>= 2 lead to massive starbursts in L > L* galaxies. At z < 2, in M > Mshock haloes hosting groups, the gas is heated by a virial shock, and being dilute it becomes vulnerable to feedback from energetic sources such as active galactic nuclei. This shuts off gas supply and prevents further star formation, leading by passive evolution to `red-and-dead' massive spheroids starting at z~ 1. A minimum in feedback efficiency near Mshock explains the observed minimum in M/L and the qualitative features of the star formation history. The cold flows provide a hint for solving the angular momentum problem. When these processes are incorporated in simulations they recover the main bimodality features and solve other open puzzles.

  1. Flow regime classification in air-magnetic fluid two-phase flow.

    PubMed

    Kuwahara, T; De Vuyst, F; Yamaguchi, H

    2008-05-21

    A new experimental/numerical technique of classification of flow regimes (flow patterns) in air-magnetic fluid two-phase flow is proposed in the present paper. The proposed technique utilizes the electromagnetic induction to obtain time-series signals of the electromotive force, allowing us to make a non-contact measurement. Firstly, an experiment is carried out to obtain the time-series signals in a vertical upward air-magnetic fluid two-phase flow. The signals obtained are first treated using two kinds of wavelet transforms. The data sets treated are then used as input vectors for an artificial neural network (ANN) with supervised training. In the present study, flow regimes are classified into bubbly, slug, churn and annular flows, which are generally the main flow regimes. To validate the flow regimes, a visualization experiment is also performed with a glycerin solution that has roughly the same physical properties, i.e., kinetic viscosity and surface tension, as a magnetic fluid used in the present study. The flow regimes from the visualization are used as targets in an ANN and also used in the estimation of the accuracy of the present method. As a result, ANNs using radial basis functions are shown to be the most appropriate for the present classification of flow regimes, leading to small classification errors.

  2. Flow regime classification in air magnetic fluid two-phase flow

    NASA Astrophysics Data System (ADS)

    Kuwahara, T.; DeVuyst, F.; Yamaguchi, H.

    2008-05-01

    A new experimental/numerical technique of classification of flow regimes (flow patterns) in air-magnetic fluid two-phase flow is proposed in the present paper. The proposed technique utilizes the electromagnetic induction to obtain time-series signals of the electromotive force, allowing us to make a non-contact measurement. Firstly, an experiment is carried out to obtain the time-series signals in a vertical upward air-magnetic fluid two-phase flow. The signals obtained are first treated using two kinds of wavelet transforms. The data sets treated are then used as input vectors for an artificial neural network (ANN) with supervised training. In the present study, flow regimes are classified into bubbly, slug, churn and annular flows, which are generally the main flow regimes. To validate the flow regimes, a visualization experiment is also performed with a glycerin solution that has roughly the same physical properties, i.e., kinetic viscosity and surface tension, as a magnetic fluid used in the present study. The flow regimes from the visualization are used as targets in an ANN and also used in the estimation of the accuracy of the present method. As a result, ANNs using radial basis functions are shown to be the most appropriate for the present classification of flow regimes, leading to small classification errors.

  3. A Novel Biobjective Risk-Based Model for Stochastic Air Traffic Network Flow Optimization Problem

    PubMed Central

    Cai, Kaiquan; Jia, Yaoguang; Zhu, Yanbo; Xiao, Mingming

    2015-01-01

    Network-wide air traffic flow management (ATFM) is an effective way to alleviate demand-capacity imbalances globally and thereafter reduce airspace congestion and flight delays. The conventional ATFM models assume the capacities of airports or airspace sectors are all predetermined. However, the capacity uncertainties due to the dynamics of convective weather may make the deterministic ATFM measures impractical. This paper investigates the stochastic air traffic network flow optimization (SATNFO) problem, which is formulated as a weighted biobjective 0-1 integer programming model. In order to evaluate the effect of capacity uncertainties on ATFM, the operational risk is modeled via probabilistic risk assessment and introduced as an extra objective in SATNFO problem. Computation experiments using real-world air traffic network data associated with simulated weather data show that presented model has far less constraints compared to stochastic model with nonanticipative constraints, which means our proposed model reduces the computation complexity. PMID:26180842

  4. Liquid phase evaporation on the normal shock wave in moist air transonic flows in nozzles

    NASA Astrophysics Data System (ADS)

    Dykas, Sławomir; Szymański, Artur; Majkut, Mirosław

    2017-06-01

    This paper presents a numerical analysis of the atmospheric air transonic flow through de Laval nozzles. By nature, atmospheric air always contains a certain amount of water vapor. The calculations were made using a Laval nozzle with a high expansion rate and a convergent-divergent (CD) "half-nozzle", referred to as a transonic diffuser, with a much slower expansion rate. The calculations were performed using an in-house CFD code. The computational model made it possible to simulate the formation of the liquid phase due to spontaneous condensation of water vapor contained in moist air. The transonic flow calculations also take account of the presence of a normal shock wave in the nozzle supersonic part to analyze the effect of the liquid phase evaporation.

  5. A Novel Biobjective Risk-Based Model for Stochastic Air Traffic Network Flow Optimization Problem.

    PubMed

    Cai, Kaiquan; Jia, Yaoguang; Zhu, Yanbo; Xiao, Mingming

    2015-01-01

    Network-wide air traffic flow management (ATFM) is an effective way to alleviate demand-capacity imbalances globally and thereafter reduce airspace congestion and flight delays. The conventional ATFM models assume the capacities of airports or airspace sectors are all predetermined. However, the capacity uncertainties due to the dynamics of convective weather may make the deterministic ATFM measures impractical. This paper investigates the stochastic air traffic network flow optimization (SATNFO) problem, which is formulated as a weighted biobjective 0-1 integer programming model. In order to evaluate the effect of capacity uncertainties on ATFM, the operational risk is modeled via probabilistic risk assessment and introduced as an extra objective in SATNFO problem. Computation experiments using real-world air traffic network data associated with simulated weather data show that presented model has far less constraints compared to stochastic model with nonanticipative constraints, which means our proposed model reduces the computation complexity.

  6. Annoyance due to noise and air pollution to the residents of heavily frequented streets

    NASA Technical Reports Server (NTRS)

    Wanner, H. U.; Wehrli, B.; Nemecek, J.; Turrian, V.

    1980-01-01

    The residents of different streets with varying traffic density and building density were questioned about annoyance due to traffic noise and air pollution. Results show that annoyance felt is dependent not only on the measured noise levels and/or air pollution concentrations, but that there do exist interactions between the residential quarters and annoyance. These interactions should be considered when fixing the limits and standards.

  7. Measurement of velocity of air flow in the sinus maxillaris.

    PubMed

    Müsebeck, K; Rosenberg, H

    1979-03-01

    Anemometry with the hot wire and hot film technique previously described, enables the rhinologist to record slow and rapidly changing air flow in the maxillary sinus. The advantages and disadvantages of this method are considered. Anemometry together with manometry may be designated sinumetry and used as a diagnostic procedure following sinuscopy in chronic maxillary sinus disease. The value of the function from velocity of time allows the estimation of flow-volume in the sinus. Furthermore, the method is useful to evaluate the optimal therapy to restore ventilation in the case of an obstructed ostium demonstrated before and after surgical opening in the inferior meatus.

  8. Character of energy flow in air shower core

    NASA Technical Reports Server (NTRS)

    Mizushima, K.; Asakimori, K.; Maeda, T.; Kameda, T.; Misaki, Y.

    1985-01-01

    Energy per charged particle near the core of air showers was measured by 9 energy flow detectors, which were the combination of Cerenkov counters and scintillators. Energy per particle of each detector was normalized to energy at 2m from the core. The following results were obtained as to the energy flow: (1) integral frequency distribution of mean energy per particle (averaged over 9 detectors) is composed of two groups separated distinctly; and (2) showers contained in one group show an anisotropy of arrival direction.

  9. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  10. Vision and air flow combine to streamline flying honeybees

    PubMed Central

    Taylor, Gavin J.; Luu, Tien; Ball, David; Srinivasan, Mandyam V.

    2013-01-01

    Insects face the challenge of integrating multi-sensory information to control their flight. Here we study a ‘streamlining' response in honeybees, whereby honeybees raise their abdomen to reduce drag. We find that this response, which was recently reported to be mediated by optic flow, is also strongly modulated by the presence of air flow simulating a head wind. The Johnston's organs in the antennae were found to play a role in the measurement of the air speed that is used to control the streamlining response. The response to a combination of visual motion and wind is complex and can be explained by a model that incorporates a non-linear combination of the two stimuli. The use of visual and mechanosensory cues increases the strength of the streamlining response when the stimuli are present concurrently. We propose this multisensory integration will make the response more robust to transient disturbances in either modality. PMID:24019053

  11. Vision and air flow combine to streamline flying honeybees.

    PubMed

    Taylor, Gavin J; Luu, Tien; Ball, David; Srinivasan, Mandyam V

    2013-01-01

    Insects face the challenge of integrating multi-sensory information to control their flight. Here we study a 'streamlining' response in honeybees, whereby honeybees raise their abdomen to reduce drag. We find that this response, which was recently reported to be mediated by optic flow, is also strongly modulated by the presence of air flow simulating a head wind. The Johnston's organs in the antennae were found to play a role in the measurement of the air speed that is used to control the streamlining response. The response to a combination of visual motion and wind is complex and can be explained by a model that incorporates a non-linear combination of the two stimuli. The use of visual and mechanosensory cues increases the strength of the streamlining response when the stimuli are present concurrently. We propose this multisensory integration will make the response more robust to transient disturbances in either modality.

  12. Interrelationships of petiole air canal architecture, water depth and convective air flow in Nymphaea odorata (Nymphaeaceae)

    USDA-ARS?s Scientific Manuscript database

    Premise of the study--Nymphaea odorata grows in water up to 2 m deep, producing fewer, larger leaves in deeper water. This species has a convective flow system that moves gases from younger leaves through submerged parts to older leaves, aerating submerged parts. Petiole air canals are in the conv...

  13. Development of an air flow thermal balance calorimeter

    NASA Technical Reports Server (NTRS)

    Sherfey, J. M.

    1972-01-01

    An air flow calorimeter, based on the idea of balancing an unknown rate of heat evolution with a known rate of heat evolution, was developed. Under restricted conditions, the prototype system is capable of measuring thermal wattages from 10 milliwatts to 1 watt, with an error no greater than 1 percent. Data were obtained which reveal system weaknesses and point to modifications which would effect significant improvements.

  14. Electron concentration distribution in a glow discharge in air flow

    NASA Astrophysics Data System (ADS)

    Mukhamedzianov, R. B.; Gaisin, F. M.; Sabitov, R. A.

    1989-04-01

    Electron concentration distributions in a glow discharge in longitudinal and vortex air flows are determined from the attenuation of the electromagnetic wave passing through the plasma using microwave probes. An analysis of the distribution curves obtained indicates that electron concentration decreases in the direction of the anode. This can be explained by charge diffusion toward the chamber walls and electron recombination and sticking within the discharge.

  15. Methods of Visually Determining the Air Flow Around Airplanes

    NASA Technical Reports Server (NTRS)

    Gough, Melvin N; Johnson, Ernest

    1932-01-01

    This report describes methods used by the National Advisory Committee for Aeronautics to study visually the air flow around airplanes. The use of streamers, oil and exhaust gas streaks, lampblack and kerosene, powdered materials, and kerosene smoke is briefly described. The generation and distribution of smoke from candles and from titanium tetrachloride are described in greater detail because they appear most advantageous for general application. Examples are included showing results of the various methods.

  16. Numerical simulation in finite elements of turbulent flows of viscous incompressible fluids in air intakes

    NASA Astrophysics Data System (ADS)

    Begue, C.; Periaux, J.; Perrier, P.; Pouletty, C.

    1985-11-01

    A self-adaptive finite-element method, coupled to a homogenization model of turbulence, is presented for the numerical simulation of unsteady turbulent flow of viscous fluids in air intakes. The nonlinear subproblem due to the convection is solved by an iterative algorithm, and the linear Stokes subproblem due to the diffusion is solved by a Hood-Taylor type iterative algorithm. An efficient and precise minielement approximation is used, and the adaptive mesh procedure is automatic in the calculation, using the physical criteria of rotation and divergence to determine the submeshing zones. The numerical method is demonstrated for the example of three-dimensional laminar flow around and in air intake at a Reynolds number of 200.

  17. Numerical characterization of the hydrodynamics and thermal behavior of air flow in flexible air distribution system

    NASA Astrophysics Data System (ADS)

    Gharehdaghi, Samad; Moujaes, Samir

    2013-10-01

    Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States . Very few empirical or predictive data are available though to help provide the HVAC design engineer with reliable information . Moreover, because of the ducts flexibility, the shapes of these ducts offer a different set of operating fluid flow and thermal conditions from traditional smooth metal ducts. Hence, both the flow field and heat transfer through this kind of ducts are much more complex and merit to be analyzed from a numerical predictive approach. The aim of this research paper is to compute some of the hydrodynamic and heat transfer characteristics of the air flow inside these ducts over a range of Re numbers commonly used in the flow conditions of these air distribution systems. The information resulting from this CFD simulation, where a κ-ɛ turbulent model is used to predict the flow conditions, provide pressure drop and average convective heat transfer coefficients that exist in these ducts and was compared to previously found data. Circulation zones in the depressions of these ducts are found to exist which are suspected of influencing the pressured drop and heat transfer coefficients as compared to smooth ducts. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal entrance regions than what would be expected in smooth ducts under the same turbulent conditions.

  18. An experimental study on the effect of air bubble injection on the flow induced rotational hub

    SciTech Connect

    Nouri, N.M.; Sarreshtehdari, A.

    2009-01-15

    Modification of shear stress due to air bubbles injection in a rotary device was investigated experimentally. Air bubbles inject to the water flow crosses the neighbor of the hub which can rotate just by water flow shear stresses, in this device. Increasing air void fraction leads to decrease of shear stresses exerted on the hub surface until in high void fractions, the hub motion stopped as observed. Amount of skin friction decrease has been estimated by counting central hub rotations. Wall shear stress was decreased by bubble injection in all range of tested Reynolds number, changing from 50,378 to 71,238, and also by increasing air void fraction from zero to 3.06%. Skin friction reduction more than 85% was achieved in this study as maximum measured volume of air fraction injected to fluid flow while bubbles are distinct and they do not make a gas layer. Significant skin friction reduction obtained in this special case indicate that using small amount of bubble injection causes large amount of skin friction reduction in some rotary parts in the liquid phases like as water. (author)

  19. 30 CFR 57.22211 - Air flow (I-A mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Methane in Metal and Nonmetal Mines Ventilation § 57.22211 Air flow (I-A mines). The average air velocity... openings nearest the face, shall be at least 40 feet per minute. The velocity of air ventilating each...

  20. 30 CFR 57.22211 - Air flow (I-A mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Methane in Metal and Nonmetal Mines Ventilation § 57.22211 Air flow (I-A mines). The average air velocity... openings nearest the face, shall be at least 40 feet per minute. The velocity of air ventilating each...

  1. 30 CFR 57.22211 - Air flow (I-A mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Methane in Metal and Nonmetal Mines Ventilation § 57.22211 Air flow (I-A mines). The average air velocity... openings nearest the face, shall be at least 40 feet per minute. The velocity of air ventilating each...

  2. 30 CFR 57.22211 - Air flow (I-A mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Methane in Metal and Nonmetal Mines Ventilation § 57.22211 Air flow (I-A mines). The average air velocity... openings nearest the face, shall be at least 40 feet per minute. The velocity of air ventilating each...

  3. 30 CFR 75.152 - Tests of air flow; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of air flow; qualified person. 75.152....152 Tests of air flow; qualified person. A person is a qualified person within the meaning of the provisions of Subpart D—Ventilation of this part requiring that tests of air flow be made by a...

  4. SIMPLIFIED MODELING OF AIR FLOW DYNAMICS IN SSD RADON MITIGATION SYSTEMS FOR RESIDENCES WITH GRAVEL BEDS

    EPA Science Inventory

    In an attempt to better understand the dynamics of subslab air flow, the report suggests that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained between two impermeable disks. (NOTE: Many subslab depressurization syste...

  5. 30 CFR 75.152 - Tests of air flow; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Tests of air flow; qualified person. 75.152....152 Tests of air flow; qualified person. A person is a qualified person within the meaning of the provisions of Subpart D—Ventilation of this part requiring that tests of air flow be made by a qualified...

  6. Flow over a Ram-Air Parachute Canopy

    NASA Astrophysics Data System (ADS)

    Eslambolchi, Ali; Johari, Hamid

    2012-11-01

    The flow field over a full-scale, ram-air personnel parachute canopy was investigated numerically using a finite-volume flow solver coupled with the Spalart-Allmaras turbulence model. Ram-air parachute canopies resemble wings with arc-anhedral, surface protuberances, and an open leading edge for inflation. The rectangular planform canopy had an aspect ratio of 2.2 and was assumed to be rigid and impermeable. The chord-based Reynolds number was 3.2 million. Results indicate that the oncoming flow barely penetrates the canopy opening, and creates a large separation bubble below the lower lip of canopy. A thick boundary layer exists over the entire lower surface of the canopy. The flow over the upper surface of the canopy remains attached for an extended fraction of the chord. Lift increases linearly with angle of attack up to about 12 degrees. To assess the capability of lifting-line theory in predicting the forces on the canopy, the lift and drag data from a two-dimensional simulation of the canopy profile were extended using finite-wing expressions and compared with the forces from the present simulations. The finite-wing predicted lift and drag trends compare poorly against the full-span simulation, and the maximum lift-to-drag ratio is over-predicted by 36%. Sponsored by the US Army NRDEC.

  7. Thermistor based, low velocity isothermal, air flow sensor

    NASA Astrophysics Data System (ADS)

    Cabrita, Admésio A. C. M.; Mendes, Ricardo; Quintela, Divo A.

    2016-03-01

    The semiconductor thermistor technology is applied as a flow sensor to measure low isothermal air velocities (<2 ms-1). The sensor is subjected to heating and cooling cycles controlled by a multifunctional timer. In the heating stage, the alternating current of a main AC power supply source guarantees a uniform thermistor temperature distribution. The conditioning circuit assures an adequate increase of the sensors temperature and avoids the thermal disturbance of the flow. The power supply interruption reduces the consumption from the source and extends the sensors life time. In the cooling stage, the resistance variation of the flow sensor is recorded by the measuring chain. The resistive sensor parameters proposed vary significantly and feature a high sensitivity to the flow velocity. With the aid of a computer, the data transfer, storage and analysis provides a great advantage over the traditional local anemometer readings. The data acquisition chain has a good repeatability and low standard uncertainties. The proposed method measures isothermal air mean velocities from 0.1 ms-1 to 2 ms-1 with a standard uncertainty error less than 4%.

  8. The measurement error analysis when a pitot probe is used in supersonic air flow

    NASA Astrophysics Data System (ADS)

    Zhang, XiWen; Hao, PengFei; Yao, ZhaoHui

    2011-04-01

    Pitot probes enable a simple and convenient way of measuring mean velocity in air flow. The contrastive numerical simulation between free supersonic airflow and pitot tube at different positions in supersonic air flow was performed using Navier-Stokes equations, the ENN scheme with time-dependent boundary conditions (TDBC) and the Spalart-Allmaras turbulence model. The physical experimental results including pitot pressure and shadowgraph are also presented. Numerical results coincide with the experimental data. The flow characteristics of the pitot probe on the supersonic flow structure show that the measurement gives actually the total pressure behind the detached shock wave by using the pitot probe to measure the total pressure. The measurement result of the distribution of the total pressure can still represent the real free jet flow. The similar features of the intersection and reflection of shock waves can be identified. The difference between the measurement results and the actual ones is smaller than 10%. When the pitot probe is used to measure the region of L=0-4 D, the measurement is smaller than the real one due to the increase of the shock wave strength. The difference becomes larger where the waves intersect. If the pitot probe is put at L=8 D-10 D, where the flow changes from supersonic to subsonic, the addition of the pitot probe turns the original supersonic flow region subsonic and causes bigger measurement errors.

  9. Measurement of temperature and velocity fields in a convective fluid flow in air using schlieren images.

    PubMed

    Martínez-González, A; Moreno-Hernández, D; Guerrero-Viramontes, J A

    2013-08-01

    A convective fluid flow in air could be regulated if the physical process were better understood. Temperature and velocity measurements are required in order to obtain a proper characterization of a convective fluid flow. In this study, we show that a classical schlieren system can be used for simultaneous measurements of temperature and velocity in a convective fluid flow in air. The schlieren technique allows measurement of the average fluid temperature and velocity integrated in the direction of the test beam. Therefore, in our experiments we considered surfaces with isothermal conditions. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow by using optical flow techniques. The algorithm implemented analyzes motion between consecutive schlieren frames to obtain a tracked sequence and finally velocity fields. The proposed technique was applied to measure the temperature and velocity fields in natural convection of air due to unconfined and confined heated rectangular plates.

  10. Cold air drainage flows subsidize montane valley ecosystem productivity.

    PubMed

    Novick, Kimberly A; Oishi, A Christopher; Miniat, Chelcy Ford

    2016-12-01

    In mountainous areas, cold air drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro-climate condition, drainage flows, local microclimate, and ecosystem carbon cycling in a southern Appalachian valley. Data from multiple long-running climate stations and multiple eddy covariance flux towers are combined with simple models for ecosystem carbon fluxes. We show that cold air drainage into the valley suppresses local temperature by several degrees at night and for several hours before and after sunset, leading to reductions in growing season respiration on the order of ~8%. As a result, we estimate that drainage flows increase growing season and annual net carbon uptake in the valley by >10% and >15%, respectively, via effects on microclimate that are not be adequately represented in regional- and global-scale terrestrial ecosystem models. Analyses driven by chamber-based estimates of soil and plant respiration reveal cold air drainage effects on ecosystem respiration are dominated by reductions to the respiration of aboveground biomass. We further show that cold air drainage proceeds more readily when cloud cover and humidity are low, resulting in the greatest enhancements to net carbon uptake in the valley under clear, cloud-free (i.e., drought-like) conditions. This is a counterintuitive result that is neither observed nor predicted outside of the valley, where nocturnal temperature and respiration increase during dry periods. This result should motivate efforts to explore how topographic flows may buffer eco-physiological processes from macroscale climate change. © 2016 John Wiley & Sons Ltd.

  11. Sensitivity study of poisson corruption in tomographic measurements for air-water flows

    SciTech Connect

    Munshi, P. ); Vaidya, M.S. )

    1993-01-01

    An application of computerized tomography (CT) for measuring void fraction profiles in two-phase air-water flows was reported earlier. Those attempts involved some special radial methods for tomographic reconstruction and the popular convolution backprojection (CBP) method. The CBP method is capable of reconstructing void profiles for nonsymmetric flows also. In this paper, we investigate the effect of corrupted CT data for gamma-ray sources and aCBP algorithm. The corruption in such a case is due to the statistical (Poisson) nature of the source.

  12. Interactions between gravity waves and cold air outflows in a stably stratified uniform flow

    NASA Technical Reports Server (NTRS)

    Lin, Yuh-Lang; Wang, Ting-An; Weglarz, Ronald P.

    1993-01-01

    Interactions between gravity waves and cold air outflows in a stably stratified uniform flow forced by various combinations of prescribed heat sinks and sources are studied using a hydrostatic two-dimensional nonlinear numerical model. The formation time for the development of a stagnation point or reversed flow at the surface is not always directly proportional to the Froude number when wave reflections exist from upper levels. A density current is able to form by the wave-otuflow interaction, even though the Froude number is greater than a critical value. This is the result of the wave-outflow interaction shifting the flow response to a different location in the characteristic parameter space. A density current is able to form or be destroyed due to the wave-outflow interaction between a traveling gravity wave and cold air outflow. This is proved by performing experiments with a steady-state heat sink and an additional transient heat source. In a quiescent fluid, a region of cold air, convergence, and upward motion is formed after the collision between two outflows produced by two prescribed heat sinks. After the collision, the individual cold air outflows lose their own identity and merge into a single, stationary, cold air outflow region. Gravity waves tend to suppress this new stationary cold air outflow after the collision. The region of upward motion associated with the collision is confined to a very shallow layer. In a moving airstream, a density current produced by a heat sink may be suppressed or enhanced nonlinearly by an adjacent heat sink due to the wave-outflow interaction.

  13. Interactions between gravity waves and cold air outflows in a stably stratified uniform flow

    NASA Technical Reports Server (NTRS)

    Lin, Yuh-Lang; Wang, Ting-An; Weglarz, Ronald P.

    1993-01-01

    Interactions between gravity waves and cold air outflows in a stably stratified uniform flow forced by various combinations of prescribed heat sinks and sources are studied using a hydrostatic two-dimensional nonlinear numerical model. The formation time for the development of a stagnation point or reversed flow at the surface is not always directly proportional to the Froude number when wave reflections exist from upper levels. A density current is able to form by the wave-otuflow interaction, even though the Froude number is greater than a critical value. This is the result of the wave-outflow interaction shifting the flow response to a different location in the characteristic parameter space. A density current is able to form or be destroyed due to the wave-outflow interaction between a traveling gravity wave and cold air outflow. This is proved by performing experiments with a steady-state heat sink and an additional transient heat source. In a quiescent fluid, a region of cold air, convergence, and upward motion is formed after the collision between two outflows produced by two prescribed heat sinks. After the collision, the individual cold air outflows lose their own identity and merge into a single, stationary, cold air outflow region. Gravity waves tend to suppress this new stationary cold air outflow after the collision. The region of upward motion associated with the collision is confined to a very shallow layer. In a moving airstream, a density current produced by a heat sink may be suppressed or enhanced nonlinearly by an adjacent heat sink due to the wave-outflow interaction.

  14. Oral air pressure and nasal air flow rate on levator veli palatini muscle activity in patients wearing a speech appliance.

    PubMed

    Tachimura, T; Hara, H; Wada, T

    1995-09-01

    This study was designed to determine if levator veli palatini muscle activity can be elicited by simultaneous changes in oral air pressure and nasal air flow when a speech appliance is in place. The speech appliances routinely worn by 15 subjects were each modified experimentally by drilling a hole in the vertical center of the pharyngeal bulb. The air flow rate into the nasal cavity through the opening in the bulb was altered by changing the circular area of the opening in the bulb from the occluded condition (Condition I), to circular area of 12.6 mm2 (4 mm in diameter; Condition II), and then to 38.5 mm2 (7 mm in diameter; Condition III). Electromyographic activity was measured from the levator veli palatini muscle with changes in nasal air flow rate and oral air pressure. Levator veli palatini muscle activity was correlated with changes in nasal air flow and oral air pressure. Increases in levator veli palatini muscle activity were associated with increases in nasal air flow rate compared to oral air pressure changes. The results indicated that aerodynamic variables of nasal air flow and oral air pressure might be involved in the neural control of speech production in individuals wearing a speech appliance, even if the subjects exhibit velopharyngeal incompetence without using a speech appliance. Also, the stimulating effect of bulb reduction therapy on velopharyngeal function might be achieved through the change in aerodynamic variables in association with the bulb reduction.

  15. Modeling Study on Air Quality Improvement due to Mobile Source Emission control Plan in Seoul Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Kim, Y. J.; Sunwoo, Y.; Hwang, I.; Song, S.; Sin, J.; Kim, D.

    2015-12-01

    A very high population and corresponding high number of vehicles in the Seoul Metropolitan Area (SMA) are aggravating the air quality of this region. The Korean government continues to make concerted efforts to improve air quality. One of the major policies that the Ministry of Environment of Korea enforced is "The Special Act for Improvement of Air Quality in SMA" and "The 1st Air Quality Management Plan of SMA". Mobile Source emission controls are an important part of the policy. Thus, it is timely to evaluate the air quality improvement due to the controls. Therefore, we performed a quantitative analysis of the difference in air quality using the Community Multiscale Air Quality (CMAQ) model and December, 2011 was set as the target period to capture the impact of the above control plans. We considered four fuel-type vehicle emission scenarios and compared the air quality improvement differences between them. The scenarios are as follows: no-control, gasoline vehicle control only, diesel vehicle control only, and control of both; utilizing the revised mobile source emissions from the Clean Air Policy Support System (CAPSS), which is the national emission inventory reflecting current policy.In order to improve the accuracy of the modeling data, we developed new temporal allocation coefficients based on traffic volume observation data and spatially reallocated the mobile source emissions using vehicle flow survey data. Furthermore, we calculated the PM10 and PM2.5 emissions of gasoline vehicles which is omitted in CAPSS.The results of the air quality modeling shows that vehicle control plans for both gasoline and diesel lead to a decrease of 0.65ppb~8.75ppb and 0.02㎍/㎥~7.09㎍/㎥ in NO2 and PM10 monthly average concentrations, respectively. The large percentage decreases mainly appear near the center of the metropolis. However, the largest NO2 decrease percentages are found in the northeast region of Gyeonggi-do, which is the province that surrounds the

  16. Effect of air pressure differential on vapor flow through sample building walls

    SciTech Connect

    Stewart, W.E. Jr.

    1998-12-31

    Laboratory scale experiments were performed on two small sample composite walls of typical building construction to determine the approximate opposing air pressure difference required to stop or significantly reduce the transmission of water vapor due to a water vapor pressure difference. The experiments used wall section samples between two controlled atmosphere chambers. One chamber was held at a temperature and humidity condition approximating that of a typical summer day, while the other chamber was controlled at a condition typical of indoor conditioned space. Vapor transmission data through the wall samples were obtained over a range of vapor pressure differentials and opposing air pressure differentials. The results show that increasing opposing air pressure differences decrease water vapor transmission, as expected, and relatively small opposing air pressure differentials are required for wall materials of small vapor permeability and large air permeability. The opposing air pressure that stopped or significantly reduced the flow of water vapor through the wall sample was determined experimentally and also compared to air pressures as predicted by an analytical model.

  17. [Pulmonary edema due to venous air embolism during craniotomy: a case report].

    PubMed

    Ishida, Kumiko; Hishinuma, Miwako; Miyazawa, Mikiko; Tanaka, Toshiyuki; Iwasawa, Ken; Kitoh, Takeshi

    2008-10-01

    We present a 35-year-old healthy male patient who developed pulmonary edema (PE) probably due to venous air embolism during craniotomy in the semi-sitting position for arteriovenous malformation (AVM). Anesthesia was maintained with oxygen, nitrous oxide, propofol and fentanyl. During craniotomy, end-tidal carbon dioxide pressure decreased suddenly from 26 to 9 mmHg. Concurrently, a decrease in oxygen saturation from 99% to 91% occurred. There were no serious changes in blood pressure and heart rate. A "mill-wheel murmur" was confirmed. PE due to venous air embolism was suspected. The operation was discontinued and the patient was transferred to the intensive care unit. In the post-operative period, the patient developed PE and made a full recovery within a week. Four months later, the patient was scheduled again for surgical excision of AVM in the semi-sitting position in the same way as the first time. Anesthesia was maintained with oxygen, air, propofol and fentanyl. Transoesophageal echocardiography and pulmonary artery catheter were used. Saline was filled at the surgical site to prevent aspiration of air bubbles and surgical procedure was performed carefully without large vein injury and uneventfully. During neurosurgical intervention in the sitting position, special attention should be paid to entry of air bubbles into the venous system which may lead to PE.

  18. Flow currents and ventilation in Langstroth beehives due to brood thermoregulation efforts of honeybees.

    PubMed

    Sudarsan, Rangarajan; Thompson, Cody; Kevan, Peter G; Eberl, Hermann J

    2012-02-21

    Beekeepers universally agree that ensuring sufficient ventilation is vital for sustaining a thriving, healthy honeybee colony. Despite this fact, surprisingly little is known about the ventilation and flow patterns in bee hives. We take a first step towards developing a model-based approach that uses computational fluid dynamics to simulate natural ventilation flow inside a standard Langstroth beehive. A 3-D model of a Langstroth beehive with one brood chamber and one honey super was constructed and inside it the honeybee colony was distributed among different clusters each occupying the different bee-spaces between frames in the brood chamber. For the purpose of modeling, each honeybee cluster was treated as an air-saturated porous medium with constant porosity. Heat and mass transfer interactions of the honeybees with the air, the outcome of metabolism, were captured in the porous medium model as source and sink terms appearing in the governing equations of fluid dynamics. The temperature of the brood that results from the thermoregulation efforts of the colony is applied as a boundary condition for the governing equations. The governing equations for heat, mass transport and fluid flow were solved using Fluent(©), a commercially available CFD program. The results from the simulations indicate that (a) both heat and mass transfer resulting from honeybee metabolism play a vital role in determining the structure of the flow inside the beehive and mass transfer cannot be neglected, (b) at low ambient temperatures, the nonuniform temperature profile on comb surfaces that results from brood incubation enhances flow through the honeybee cluster which removes much of the carbon-dioxide produced by the cluster resulting in lower carbon-dioxide concentration next to the brood, (c) increasing ambient (outside) air temperature causes ventilation flow rate to drop resulting in weaker flow inside the beehive. Flow visualization indicates that at low ambient air temperatures

  19. The acoustic excitation of air bubbles fragmenting in sheared flow.

    PubMed

    Deane, Grant B; Stokes, M Dale

    2008-12-01

    An analysis of the acoustic emissions of air bubbles fragmenting in sheared fluid flow is presented. The fragmentation of bubbles into two products only is considered. While the measured pressure amplitude is highly variable, the partition of energy between fragmentation products is highly correlated. The partition of energy between products is, on average, approximately equal irrespective of the relative sizes of the bubble products. This observation suggests that the acoustic excitation mechanism is common to both bubbles immediately prior to fragmentation. A model for the excitation mechanism based on symmetric collapse of the neck of air joining fragmentation products is proposed and found to be sufficient to explain the range of observed bubble pulse amplitudes and the equal partition of energy.

  20. Canyon air flow measurement utilizing ASME standard pitot tube arrays

    SciTech Connect

    Moncrief, B.R.

    1990-01-01

    The Savannah River Site produces nuclear materials for national defense. In addition to nuclear reactors, the site has separation facilities for reprocessing irradiated nuclear fuel. The chemical separation of highly radioactive materials takes place by remote control in large buildings called canyons. Personnel in these buildings are shielded from radiation by thick concrete walls. Contaminated air is exhausted from the canyons and contaminants are removed by sand filters prior to release to the atmosphere through a stack. When these facilities were built on a crash basis in the early 1950's, inadequate means were provided for pressure and air flow measurement. This presentation describes the challenge we faced in retrofitting a highly radioactive, heavily shielded facility with instrumentation to provide this capability.

  1. Laboratory Evaluation of Air Flow Measurement Methods for Residential HVAC Returns

    SciTech Connect

    Walker, Iain; Stratton, Chris

    2015-07-01

    This project improved the accuracy of air flow measurements used in commissioning California heating and air conditioning systems in Title 24 (Building and Appliance Efficiency Standards), thereby improving system performance and efficiency of California residences. The research team at Lawrence Berkeley National Laboratory addressed the issue that typical tools used by contractors in the field to test air flows may not be accurate enough to measure return flows used in Title 24 applications. The team developed guidance on performance of current diagnostics as well as a draft test method for use in future evaluations. The series of tests performed measured air flow using a range of techniques and devices. The measured air flows were compared to reference air flow measurements using inline air flow meters built into the test apparatus. The experimental results showed that some devices had reasonable results (typical errors of 5 percent or less) but others had much bigger errors (up to 25 percent).

  2. Internal air flow analysis of a bladeless micro aerial vehicle hemisphere body using computational fluid dynamic

    NASA Astrophysics Data System (ADS)

    Othman, M. N. K.; Zuradzman, M. Razlan; Hazry, D.; Khairunizam, Wan; Shahriman, A. B.; Yaacob, S.; Ahmed, S. Faiz; Hussain, Abadalsalam T.

    2014-12-01

    This paper explain the analysis of internal air flow velocity of a bladeless vertical takeoff and landing (VTOL) Micro Aerial Vehicle (MAV) hemisphere body. In mechanical design, before produce a prototype model, several analyses should be done to ensure the product's effectiveness and efficiency. There are two types of analysis method can be done in mechanical design; mathematical modeling and computational fluid dynamic. In this analysis, I used computational fluid dynamic (CFD) by using SolidWorks Flow Simulation software. The idea came through to overcome the problem of ordinary quadrotor UAV which has larger size due to using four rotors and the propellers are exposed to environment. The bladeless MAV body is designed to protect all electronic parts, which means it can be used in rainy condition. It also has been made to increase the thrust produced by the ducted propeller compare to exposed propeller. From the analysis result, the air flow velocity at the ducted area increased to twice the inlet air. This means that the duct contribute to the increasing of air velocity.

  3. Internal air flow analysis of a bladeless micro aerial vehicle hemisphere body using computational fluid dynamic

    SciTech Connect

    Othman, M. N. K. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Zuradzman, M. Razlan E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Hazry, D. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Khairunizam, Wan E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Shahriman, A. B. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Yaacob, S. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Ahmed, S. Faiz E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; and others

    2014-12-04

    This paper explain the analysis of internal air flow velocity of a bladeless vertical takeoff and landing (VTOL) Micro Aerial Vehicle (MAV) hemisphere body. In mechanical design, before produce a prototype model, several analyses should be done to ensure the product's effectiveness and efficiency. There are two types of analysis method can be done in mechanical design; mathematical modeling and computational fluid dynamic. In this analysis, I used computational fluid dynamic (CFD) by using SolidWorks Flow Simulation software. The idea came through to overcome the problem of ordinary quadrotor UAV which has larger size due to using four rotors and the propellers are exposed to environment. The bladeless MAV body is designed to protect all electronic parts, which means it can be used in rainy condition. It also has been made to increase the thrust produced by the ducted propeller compare to exposed propeller. From the analysis result, the air flow velocity at the ducted area increased to twice the inlet air. This means that the duct contribute to the increasing of air velocity.

  4. Changes in air temperature and its relation to ambulance transports due to heat stroke in all 47 prefectures of Japan.

    PubMed

    Murakami, Shoko; Miyatake, Nobuyuki; Sakano, Noriko

    2012-09-01

    Changes in air temperature and its relation to ambulance transports due to heat stroke in all 47 prefectures, in Japan were evaluated. Data on air temperature were obtained from the Japanese Meteorological Agency. Data on ambulance transports due to heat stroke was directly obtained from the Fire and Disaster Management Agency, Japan. We also used the number of deaths due to heat stroke from the Ministry of Health, Labour and Welfare, Japan, and population data from the Ministry of Internal Affairs and Communications. Chronological changes in parameters of air temperature were analyzed. In addition, the relation between air temperature and ambulance transports due to heat stroke in August 2010 was also evaluated by using an ecological study. Positive and significant changes in the parameters of air temperature that is, the mean air temperature, mean of the highest air temperature, and mean of the lowest air temperature were noted in all 47 prefectures. In addition, changes in air temperature were accelerated when adjusted for observation years. Ambulance transports due to heat stroke was significantly correlated with air temperature in the ecological study. The highest air temperature was significantly linked to ambulance transports due to heat stroke, especially in elderly subjects. Global warming was demonstrated in all 47 prefectures in Japan. In addition, the higher air temperature was closely associated with higher ambulance transports due to heat stroke in Japan.

  5. Deaths Due to Accidental Air Conditioner Compressor Explosion: A Case Series.

    PubMed

    Behera, Chittaranjan; Bodwal, Jatin; Sikary, Asit K; Chauhan, Mohit Singh; Bijarnia, Manjul

    2017-01-01

    In an air-conditioning system, the compressor is a large electric pump that pressurizes the refrigerant gas as part of the process of turning it back into a liquid. The explosion of an air conditioner (AC) compressor is an uncommon event, and immediate death resulted from the blast effect is not reported in forensic literature. We report three such cases in which young AC mechanics were killed on the spot due to compressor blast, while repairing the domestic split AC unit. The autopsy findings, the circumstances leading to the explosion of the compressor, are discussed in this study. © 2016 American Academy of Forensic Sciences.

  6. An air traffic flow management method based on mixed genetic algorithms

    NASA Astrophysics Data System (ADS)

    Fu, Ying

    2009-12-01

    With the air traffic congest problem becoming more and more severe, the study of air traffic flow management is more and more important. According to the character of air traffic flow management, the author analyzed the heuristic method and genetic algorithms, later put this two method together and give a new method of air traffic flow management-mixture genetic algorithms, It has global convergence, the simulation result demonstrates that the presented algorithm is effective.

  7. Air flow paths and porosity/permeability change in a saturated zone during in situ air sparging.

    PubMed

    Tsai, Yih-Jin

    2007-04-02

    This study develops methods to estimate the change in soil characteristics and associated air flow paths in a saturated zone during in situ air sparging. These objectives were achieved by performing combined in situ air sparging and tracer testing, and comparing the breakthrough curves obtained from the tracer gas with those obtained by a numerical simulation model that incorporates a predicted change in porosity that is proportional to the air saturation. The results reveal that revising the porosity and permeability according to the distribution of gas saturation is helpful in breakthrough curve fitting, however, these changes are unable to account for the effects of preferential air flow paths, especially in the zone closest to the points of air injection. It is not known the extent to which these preferential air flow paths were already present versus created, increased, or reduced as a result of the air sparging experiment. The transport of particles from around the sparging well could account for the overall increase in porosity and permeability observed in the study. Collection of soil particles in a monitoring well within 2m of the sparging well provided further evidence of the transport of particles. Transport of particles from near the sparging well also appeared to decrease the radius of influence (ROI). Methods for predicting the effects of pressurized air injection and water flow on the creation or modification of preferential air flow paths are still needed to provide a full description of the change in soil conditions that accompany air sparging.

  8. Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

    SciTech Connect

    Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.; Lowenstein, A.

    2014-09-01

    Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by first overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.

  9. Metal-air flow batteries using oxygen enriched electrolyte

    DOEpatents

    Zheng, Jian-ping; Andrei, Petru; Shellikeri, Annadanesh; Chen, Xujie

    2017-08-01

    A metal air flow battery includes an electrochemical reaction unit and an oxygen exchange unit. The electrochemical reaction unit includes an anode electrode, a cathode electrode, and an ionic conductive membrane between the anode and the cathode, an anode electrolyte, and a cathode electrolyte. The oxygen exchange unit contacts the cathode electrolyte with oxygen separate from the electrochemical reaction unit. At least one pump is provided for pumping cathode electrolyte between the electrochemical reaction unit and the oxygen exchange unit. A method for producing an electrical current is also disclosed.

  10. Measurement of retinal blood flow rate in diabetic rats: disparity between techniques due to redistribution of flow.

    PubMed

    Leskova, Wendy; Watts, Megan N; Carter, Patsy R; Eshaq, Randa S; Harris, Norman R

    2013-04-26

    Reports of altered retinal blood flow in experimental models of type I diabetes have provided contrasting results, which leads to some confusion as to whether flow is increased or decreased. The purpose of our study was to evaluate early diabetes-induced changes in retinal blood flow in diabetic rats, using two distinctly different methods. Diabetes was induced by injection of streptozotocin (STZ), and retinal blood flow rate was measured under anesthesia by a microsphere infusion technique, or by an index of flow based on the mean circulation time between arterioles and venules. Measurements in STZ rats were compared to age-matched nondiabetic controls. In addition, the retinal distribution of fluorescently-labeled red blood cells (RBCs) was viewed by confocal microscopy in excised flat mounts. Retinal blood flow rate was found to decrease by approximately 33% in the STZ rats compared to controls (P < 0.001) as assessed by the microsphere technique. However, in striking contrast, the mean circulation time through the retina was found to be almost 3× faster in the STZ rats (P < 0.01). This contradiction could be explained by flow redistribution through the superficial vessels of the diabetic retina, with this possibility supported by our observation of significantly fewer RBCs flowing through the deeper capillaries. We conclude that retinal blood flow rate is reduced significantly in the diabetic rat, with a substantial decrease of flow through the capillaries due to shunting of blood through the superficial layer, allowing rapid transit from arterioles to venules.

  11. Air-Flow Simulation in Realistic Models of the Trachea

    SciTech Connect

    Deschamps, T; Schwartz, P; Trebotich, D

    2004-12-09

    In this article we present preliminary results from a new technique for flow simulation in realistic anatomical airways. The airways are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of anatomical objects. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier- Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element gridding of the whole volume, our method directly simulates the air-flow inside the extracted surface without losing any complicated details and without building additional grids.

  12. Effect of Marangoni Flows on the Shape of Thin Sessile Droplets Evaporating into Air.

    PubMed

    Tsoumpas, Yannis; Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

    2015-12-15

    Freely receding evaporating sessile droplets of perfectly wetting liquids, for which the observed finite contact angles are attributed to evaporation, are studied with a Mach-Zehnder interferometer. The experimentally obtained droplet shapes are found to depart, under some conditions, from the classical macroscopic static profile of a sessile droplet. The observed deviations (or the absence thereof) are explained in terms of a Marangoni flow due to evaporation-induced thermal gradients along the liquid-air interface. When such a Marangoni effect is strong, the experimental profiles exhibit a maximum of the slope at a certain distance from the contact line. In this case, the axisymmetric flow is directed from the contact line to the apex (along the liquid-air interface), hence delivering more liquid to the center of the droplet and making it appear inflated. These findings are quantitatively confirmed by predictions of a lubrication model accounting for the impact of the Marangoni effect on the droplet shape.

  13. Ozone concentrations in air flowing into New York State

    NASA Astrophysics Data System (ADS)

    Aleksic, Nenad; Kent, John; Walcek, Chris

    2016-09-01

    Ozone (O3) concentrations measured at Pinnacle State Park (PSPNY), very close to the southern border of New York State, are used to estimate concentrations in air flowing into New York. On 20% of the ozone season (April-September) afternoons from 2004 to 2015, mid-afternoon 500-m back trajectories calculated from PSPNY cross New York border from the south and spend less than three hours in New York State, in this area of negligible local pollution emissions. One-hour (2p.m.-3p.m.) O3 concentrations during these inflowing conditions were 46 ± 13 ppb, and ranged from a minimum of 15 ppb to a maximum of 84 ppb. On average during 2004-2015, each year experienced 11.8 days with inflowing 1-hr O3 concentrations exceeding 50 ppb, 4.3 days with O3 > 60 ppb, and 1.5 days had O3 > 70 ppb. During the same period, 8-hr average concentrations (10a.m. to 6p.m.) exceeded 50 ppb on 10.0 days per season, while 3.9 days exceeded 60 ppb, and 70 ppb was exceeded 1.2 days per season. Two afternoons of minimal in-state emission influences with high ozone concentrations were analyzed in more detail. Synoptic and back trajectory analysis, including comparison with upwind ozone concentrations, indicated that the two periods were characterized as photo-chemically aged air containing high inflowing O3 concentrations most likely heavily influenced by pollution emissions from states upwind of New York including Pennsylvania, Tennessee, West Virginia, and Ohio. These results suggest that New York state-level attempts to comply with National Ambient Air Quality Standards by regulating in-state O3 precursor NOx and organic emissions would be very difficult, since air frequently enters New York State very close to or in excess of Federal Air Quality Standards.

  14. Mode in Composite Laminates Due to Misalignment in Air-Coupled Transducers

    NASA Astrophysics Data System (ADS)

    Chennamsetti, R.; Hood, A.; Khan, I.; Joshi, M.

    2014-07-01

    This paper presents systematic experiments carried out to study the variation in amplitude of the fundamental symmetric Lamb mode (So) due to misalignments in air-coupled transducers. In this work three misalignments—linear, orientation and synchronized orientation were intentionally introduced in the air-coupled transducers, and experiments were carried out on two glass fiber reinforced plastic laminates of different ply stacking. A-scans were captured positioning the air-coupled probes in several configurations over the laminates. In each misalignment case, variation in amplitude of So mode with respect to misalignment variable was plotted. Curves were fitted in those misalignment cases where there was sufficient experimental data. Interestingly, it was observed that Gaussian curves accurately characterize the variation in amplitude with respect to the misalignment variable.

  15. Simulations of Direct Current Glow Discharges in Supersonic Air Flow

    NASA Astrophysics Data System (ADS)

    Mahadevan, Shankar; Raja, Laxminarayan

    2008-10-01

    In recent years, there have been a significant number of computational and experimental studies investigating the application of plasma discharges as actuators for high speed flow control. The relative importance of the actuation mechanisms: volumetric heating and electrostatic forcing can be established by developing self-consistent models of the plasma and bulk supersonic flow. To simulate the plasma discharge in a supersonic air stream, a fluid model of the glow discharge is coupled with a compressible Navier-Stokes solver in a self-consistent manner. Source terms for the momentum and energy equations are calculated from the plasma model and input into the Navier-Stokes solver. In turn, the pressure, gas temperature and velocity fields from the Navier-Stokes solution are fed back into the plasma model. The results include plasma species number density contour maps in the absence and presence of Mach 3 supersonic flow, and the corresponding effect of the glow discharge on gas dynamic properties such as the gas pressure and temperature. We also examine the effect of increasing the discharge voltage on the structure of the discharge and its corresponding effect on the supersonic flow.

  16. Numerical simulation of air flow in a model of lungs with mouth cavity

    NASA Astrophysics Data System (ADS)

    Elcner, Jakub; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav

    2012-04-01

    The air flow in a realistic geometry of human lung is simulated with computational flow dynamics approach as stationary inspiration. Geometry used for the simulation includes oral cavity, larynx, trachea and bronchial tree up to the seventh generation of branching. Unsteady RANS approach was used for the air flow simulation. Velocities corresponding to 15, 30 and 60 litres/min of flow rate were set as boundary conditions at the inlet to the model. These flow rates are frequently used as a representation of typical human activities. Character of air flow in the model for these different flow rates is discussed with respect to future investigation of particle deposition.

  17. [Fire disaster due to deflagration of a propane gas-air mixture].

    PubMed

    Nadjem, Hadi; Vogt, Susanne; Simon, Karl-Heinz; Pollak, Stefan; Geisenberger, Dorothee; Kramer, Lena; Pircher, Rebecca; Perdekampl, Markus Große; Thierauf-Emberger, Annette

    2015-01-01

    On 26 Nov 2012, a serious fire occurred at Neustadt/Black Forest in which 14 persons in a sheltered workshop died and 10 other individuals were injured. The fire was caused by the unbridled escape of propane gas due to accidental disconnection of the screw fixing between a gas bottle and a catalytic heater. Deflagration of the propane gas-air mixture set the workshop facilities on fire. In spite of partly extensive burns the fatally injured victims could be rapidly identified. The results of the fire investigations at the scene and the autopsy findings are presented. Carboxyhemoglobin concentrations ranged between 8 and 56 % and signs of fire fume inhalation were present in all cases. Three victims had eardrum ruptures due to the sudden increase in air pressure during the deflagration.

  18. A neural network based optimization system provides on-line coal fired furnace air flow balancing for heat rate improvement and NO{sub x} reduction

    SciTech Connect

    Radl, B.J.; Roland, W. Jr.

    1995-12-31

    The optimization system provides on-line, real-time air flow balancing without extensive testing or large complex physical models. NO{sub x} emissions and unit heat rate are very sensitive to air distribution and turbulence in the combustion zone. These issues are continuously changing due to ambient conditions, coal quality and the condition of plant equipment. This report discusses applying on-line, real-time and neural network to adjust secondary air flow and overfire air flow to reduce NO{sub x} and improve heat rate on various coal fired boiler designs.

  19. 30 CFR 57.22211 - Air flow (I-A mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Air flow (I-A mines). 57.22211 Section 57.22211... Methane in Metal and Nonmetal Mines Ventilation § 57.22211 Air flow (I-A mines). The average air velocity... at a work place shall be at least 20 feet per minute. ...

  20. 40 CFR 86.313-79 - Air flow measurement specifications; diesel engines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... upper limit for the engine operating condition which results in maximum air flow, as established by the... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Air flow measurement specifications... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES...

  1. Dry Flowing Abrasive Decontamination Technique for Pipe Systems with Swirling Air Flow

    SciTech Connect

    Kameo, Yutaka; Nakashima, Mikio; Hirabayashi, Takakuni

    2003-10-15

    A dry abrasive decontamination method was developed for removing radioactive corrosion products from surfaces of coolant pipe systems in decommissioning of a nuclear power plant. Erosion behavior of inside surfaces of stainless and carbon steel pipes by a swirling air flow containing alumina or cast-iron grit abrasive was studied. Erosion depths of the test pipes were approximately proportional to an abrasive concentration in air and an exponent of flow rate of airstream. The experimental results indicated that the present method could keep satisfactory erosion ability of abrasives even for a large-size pipe. The present method was successfully applied to {sup 60}Co-contaminated specimens sampled from a pipe of the water cleanup system of the Japan Power Demonstration Reactor.

  2. Phonatory air flow characteristics of adductor spasmodic dysphonia and muscle tension dysphonia.

    PubMed

    Higgins, M B; Chait, D H; Schulte, L

    1999-02-01

    The purpose of this study was to determine if phonatory air flow characteristics differed among women with adductor spasmodic dysphonia (AdSD), muscle tension dysphonia (MTD), and normal phonation. Phonatory air flow signals were gathered during [pa] syllable repetitions. Mean phonatory air flow, coefficients of variation, and the presence of large air flow perturbations (75 ml/s or more) were examined for the three groups of speakers. There was no significant difference in mean phonatory air flow across groups, and very large intersubject variation in mean phonatory air flow occurred for both the AdSD and MTD groups. Coefficients of variation were similar for the groups of women with MTD and normal phonation but were significantly larger for the group with AdSD. Air flow perturbations were common with AdSD and rare with MTD. Relatively large coefficients of variation and air flow perturbations of at least 75 ml/s did occur for some women with normal voices who were 70 years of age or older. It appears that intrasubject variability in phonatory air flow may aid in the differentiation of AdSD and MTD when used in conjunction with other elements of a thorough voice evaluation. However, the potential contribution of aging to increased intrasubject variability in phonatory air flow must be considered when interpreting findings.

  3. Graphical User Interface Development for Representing Air Flow Patterns

    NASA Technical Reports Server (NTRS)

    Chaudhary, Nilika

    2004-01-01

    In the Turbine Branch, scientists carry out experimental and computational work to advance the efficiency and diminish the noise production of jet engine turbines. One way to do this is by decreasing the heat that the turbine blades receive. Most of the experimental work is carried out by taking a single turbine blade and analyzing the air flow patterns around it, because this data indicates the sections of the turbine blade that are getting too hot. Since the cost of doing turbine blade air flow experiments is very high, researchers try to do computational work that fits the experimental data. The goal of computational fluid dynamics is for scientists to find a numerical way to predict the complex flow patterns around different turbine blades without physically having to perform tests or costly experiments. When visualizing flow patterns, scientists need a way to represent the flow conditions around a turbine blade. A researcher will assign specific zones that surround the turbine blade. In a two-dimensional view, the zones are usually quadrilaterals. The next step is to assign boundary conditions which define how the flow enters or exits one side of a zone. way of setting up computational zones and grids, visualizing flow patterns, and storing all the flow conditions in a file on the computer for future computation. Such a program is necessary because the only method for creating flow pattern graphs is by hand, which is tedious and time-consuming. By using a computer program to create the zones and grids, the graph would be faster to make and easier to edit. Basically, the user would run a program that is an editable graph. The user could click and drag with the mouse to form various zones and grids, then edit the locations of these grids, add flow and boundary conditions, and finally save the graph for future use and analysis. My goal this summer is to create a graphical user interface (GUI) that incorporates all of these elements. I am writing the program in

  4. Graphical User Interface Development for Representing Air Flow Patterns

    NASA Technical Reports Server (NTRS)

    Chaudhary, Nilika

    2004-01-01

    In the Turbine Branch, scientists carry out experimental and computational work to advance the efficiency and diminish the noise production of jet engine turbines. One way to do this is by decreasing the heat that the turbine blades receive. Most of the experimental work is carried out by taking a single turbine blade and analyzing the air flow patterns around it, because this data indicates the sections of the turbine blade that are getting too hot. Since the cost of doing turbine blade air flow experiments is very high, researchers try to do computational work that fits the experimental data. The goal of computational fluid dynamics is for scientists to find a numerical way to predict the complex flow patterns around different turbine blades without physically having to perform tests or costly experiments. When visualizing flow patterns, scientists need a way to represent the flow conditions around a turbine blade. A researcher will assign specific zones that surround the turbine blade. In a two-dimensional view, the zones are usually quadrilaterals. The next step is to assign boundary conditions which define how the flow enters or exits one side of a zone. way of setting up computational zones and grids, visualizing flow patterns, and storing all the flow conditions in a file on the computer for future computation. Such a program is necessary because the only method for creating flow pattern graphs is by hand, which is tedious and time-consuming. By using a computer program to create the zones and grids, the graph would be faster to make and easier to edit. Basically, the user would run a program that is an editable graph. The user could click and drag with the mouse to form various zones and grids, then edit the locations of these grids, add flow and boundary conditions, and finally save the graph for future use and analysis. My goal this summer is to create a graphical user interface (GUI) that incorporates all of these elements. I am writing the program in

  5. Experimental study of pressure fluctuations and flow perturbations in air flow through vibrating pipes

    NASA Astrophysics Data System (ADS)

    Bagchi, K.; Gupta, S. K.; Kushari, A.; Iyengar, N. G. R.

    2009-12-01

    This paper discusses the results of an experimental study of the effect of pipe oscillations on the wall pressure field and flow rate through a metallic pipe with air flowing through it. The data presented in this paper show that the frequencies of pressure oscillations in a non-oscillating pipe are identical to the natural structural modes of the pipe suggesting the influence of structural properties on the fluid dynamics of the flow. The results presented in this paper also show that the wall pressure undergoes both a temporal as well as a spatial oscillation if the pipe is forced to oscillate periodically. The pressure oscillations are found to be harmonics of the pipe oscillations. There is a drop in the mean pressure when the pipe is subjected to periodic oscillations. The flow rate through the pipe is seen to undergo a periodic change over a range of almost 7 percent variation when the pipe is oscillated. The study presented in this paper elucidates the dominant effect of system dynamics on determining the flow behavior through a rigid pipe. The adverse effect of flow oscillations, induced by pipe motion, can lead to departure of the flow from the intended design conditions and can render the fluid supply system inadequate.

  6. An evolutionary outlook of air traffic flow management techniques

    NASA Astrophysics Data System (ADS)

    Kistan, Trevor; Gardi, Alessandro; Sabatini, Roberto; Ramasamy, Subramanian; Batuwangala, Eranga

    2017-01-01

    In recent years Air Traffic Flow Management (ATFM) has become pertinent even in regions without sustained overload conditions caused by dense traffic operations. Increasing traffic volumes in the face of constrained resources has created peak congestion at specific locations and times in many areas of the world. Increased environmental awareness and economic drivers have combined to create a resurgent interest in ATFM as evidenced by a spate of recent ATFM conferences and workshops mediated by official bodies such as ICAO, IATA, CANSO the FAA and Eurocontrol. Significant ATFM acquisitions in the last 5 years include South Africa, Australia and India. Singapore, Thailand and Korea are all expected to procure ATFM systems within a year while China is expected to develop a bespoke system. Asia-Pacific nations are particularly pro-active given the traffic growth projections for the region (by 2050 half of all air traffic will be to, from or within the Asia-Pacific region). National authorities now have access to recently published international standards to guide the development of national and regional operational concepts for ATFM, geared to Communications, Navigation, Surveillance/Air Traffic Management and Avionics (CNS+A) evolutions. This paper critically reviews the field to determine which ATFM research and development efforts hold the best promise for practical technological implementations, offering clear benefits both in terms of enhanced safety and efficiency in times of growing air traffic. An evolutionary approach is adopted starting from an ontology of current ATFM techniques and proceeding to identify the technological and regulatory evolutions required in the future CNS+A context, as the aviation industry moves forward with a clearer understanding of emerging operational needs, the geo-political realities of regional collaboration and the impending needs of global harmonisation.

  7. Secondary flow mixing due to biofilm growth in capillaries of varying dimensions.

    PubMed

    Hornemann, Jennifer A; Codd, Sarah L; Fell, Robert J; Stewart, Philip S; Seymour, Joseph D

    2009-06-01

    Using a magnetic resonance microscopy (MRM) technique, velocity perturbations due to biofouling in capillaries were detected in 3D velocity maps. The velocity images in each of the three square capillary sizes (2, 0.9, and 0.5 mm i.d.) tested indicate secondary flow in both the x- and y-directions for the biofouled capillaries. Similar flow maps generated in a clean square capillary show only an axial component. Investigation of these secondary flows and their geometric and dynamic similarity is the focus of this study. The results showed significant secondary flows present in the 0.9 mm i.d. capillary, on the scale of 20% of the bulk fluid flow. Since this is the "standard 1 mm" size capillary used in confocal microscopy laboratory bioreactors to investigate biofilm properties, it is important to understand how these enhanced flows impact bioreactor transport. Copyright 2009 Wiley Periodicals, Inc.

  8. Secondary Flow Mixing due to Biofilm Growth in Capillaries of Varying Dimensions

    PubMed Central

    Hornemann, Jennifer A.; Codd, Sarah L.; Fell, Robert J.; Stewart, Philip S.; Seymour, Joseph D.

    2009-01-01

    Using a magnetic resonance microscopy (MRM) technique, velocity perturbations due to biofouling in capillaries were detected in 3-D velocity maps. The velocity images in each of the three square capillary sizes (2 mm, 0.9 mm, and 0.5 mm i.d.) tested indicate secondary flow in both the x and y directions for the biofouled capillaries. Similar flow maps generated in a clean square capillary show only an axial component. Investigation of these secondary flows and their geometric and dynamic similarity is the focus of this paper. The results showed significant secondary flows present in the 0.9 mm i.d. capillary, on the scale of 20% of the bulk fluid flow. Since this is the “standard 1 mm” size capillary used in confocal microscopy laboratory bioreactors to investigate biofilm properties, it is important to understand how these enhanced flows impact bioreactor transport. PMID:19191352

  9. THE PATTERN OF AIR FLOW OUT OF THE MOUTH DURING SPEECH.

    ERIC Educational Resources Information Center

    LANE, H.; AND OTHERS

    SINCE THE 19TH CENTURY, KYMOGRAPHIC RECORDING OF TOTAL AIR FLOW OUT OF THE MOUTH HAS BEEN USED TO DIAGNOSE THE VARYING DURATIONS AND DEGREES OF CONSTRICTIONS OF THE VOCAL TRACT DURING SPEECH. THE PRESENT PROJECT ATTEMPTS TO INTRODUCE A SECOND DIMENSION TO RECORDINGS OF AIR FLOW OUT OF THE MOUTH--NAMELY, CROSS-SECTIONAL AREA OF FLOW--ON THE…

  10. Wind flow modulation due to variations of the water surface roughness

    NASA Astrophysics Data System (ADS)

    Shomina, Olga; Ermakov, Stanislav; Kapustin, Ivan; Lazareva, Tatiana

    2016-04-01

    Air-ocean interaction is a classical problem in atmosphere and ocean physics, which has important geophysical applications related to calculation of vertical and horizontal humidity, aerosol and gas fluxes, development of global climate models and weather forecasts. The structure of wind flow over fixed underlying surfaces, such as forestry, buildings, mountains, is well described, while the interaction between a rough water surface and turbulent wind is far more complicated because of the presence of wind waves with different wavelength and amplitudes and propagating with different velocities and directions. The aim of this study was to investigate experimentally the variability of the wind profile structure due to variations of wave characteristics. The surface roughness variations were produced using a) surfactant films (oleic acid) spread on the water surface and b) mechanically generated waves superimposed on wind waves. The first case is related to oil slicks on sea surface, the second one - to the sea swell, which propagates into zones with lower wind velocities and interacts with wind flow. Laboratory experiments were conducted in the Oval Wind Wave Tank (OWWT) at the Institute of Applied Physics, cross-section of the wind channel is 30 cm x30 cm. Wave amplitude and the spectrum of surface waves were measured by a wire wave gauge, the wind speed was measured using a hot-wire anemometer DISA and a Pitot tube. In the experiments with surfactants, two frequencies of dripping of the oleic acid were studied, so that low concentration films with the elasticity parameters of about 19 mN/m and the high concentration ("thick") films with the elasticity of 34 mN/m were formed. In the experiments with mechanically generated waves (MGW) different regimes were studied with MGW amplitude of 3.4 mm and of 4.4 mm, and with MGW frequencies of 3.3 Hz and 3.7 Hz. It was shown, that: a) the mean velocity of the wind flow in the presence of surfactant and MGW can be described

  11. New sensor for measurement of low air flow velocity. Phase I final report

    SciTech Connect

    Hashemian, H.M.; Hashemian, M.; Riggsbee, E.T.

    1995-08-01

    The project described here is the Phase I feasibility study of a two-phase program to integrate existing technologies to provide a system for determining air flow velocity and direction in radiation work areas. Basically, a low air flow sensor referred to as a thermocouple flow sensor has been developed. The sensor uses a thermocouple as its sensing element. The response time of the thermocouple is measured using an existing in-situ method called the Loop Current Step Response (LCSR) test. The response time results are then converted to a flow signal using a response time-versus-flow correlation. The Phase I effort has shown that a strong correlation exists between the response time of small diameter thermocouples and the ambient flow rate. As such, it has been demonstrated that thermocouple flow sensors can be used successfully to measure low air flow rates that can not be measured with conventional flow sensors. While the thermocouple flow sensor developed in this project was very successful in determining air flow velocity, determining air flow direction was beyond the scope of the Phase I project. Nevertheless, work was performed during Phase I to determine how the new flow sensor can be used to determine the direction, as well as the velocity, of ambient air movements. Basically, it is necessary to use either multiple flow sensors or move a single sensor in the monitoring area and make flow measurements at various locations sweeping the area from top to bottom and from left to right. The results can then be used with empirical or physical models, or in terms of directional vectors to estimate air flow patterns. The measurements can be made continuously or periodically to update the flow patterns as they change when people and objects are moved in the monitoring area. The potential for using multiple thermocouple flow sensors for determining air flow patterns will be examined in Phase II.

  12. Impact of traffic flows and wind directions on air pollution concentrations in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Kim, Youngkook; Guldmann, Jean-Michel

    2011-05-01

    Vehicle emissions are responsible for a substantial share of urban air pollution concentrations. Various integrated air quality modeling systems have been developed to analyze the consequences of air pollution caused by traffic flows. However, the quantitative relationship between vehicle-kilometers-traveled (VKT) and pollution concentrations while considering wind direction effects has rarely been explored in the context of land-use regression models (LUR). In this research, VKTs occurring within circular buffers around air pollution monitoring stations are simulated, using a traffic assignment model, and weighted by eight wind directions frequencies. The relationships between monitored pollution concentrations and weighted VKTs are estimated using regression analysis. In general, the wind direction weighted VKT variable increases the explanatory power of the models, particularly for nitrogen dioxide and carbon monoxide. The case of ozone is more complex, due to the effects of solar radiation, which appears to overwhelm the effects of wind direction in the afternoon hours. The statistical significance of the weighted VKT variable is high, which makes the models appropriate for impact analysis of traffic flow growth.

  13. Drag reductions and the air-water interface stability of superhydrophobic surfaces in rectangular channel flow

    NASA Astrophysics Data System (ADS)

    Zhang, Jingxian; Yao, Zhaohui; Hao, Pengfei

    2016-11-01

    Flow in a rectangular channel with superhydrophobic (SH) top and bottom walls was investigated experimentally. Different SH surfaces, including hierarchical structured surfaces and surfaces with different micropost sizes (width and spacing) but the same solid fraction, were fabricated and measured. Pressure loss and flow rate in the channel with SH top and bottom walls were measured, with Reynolds number changing from 700 to 4700, and the corresponding friction factor for the SH surface was calculated. The statuses of the air plastron on different SH surfaces were observed during the experiment. In our experiment, compared with the experiment for the smooth surface, drag reductions were observed for all SH surfaces, with the largest drag reduction of 42.2%. It was found that the hierarchy of the microstructure can increase the drag reduction by decreasing the solid fraction and enhancing the stability of the air-water interface. With a fixed solid fraction, the drag reduction decreases as the post size (width and spacing) increases, due to the increasing curvature and instability effects of the air-water interface. A correlation parameter between the contact angle hysteresis, the air-water interface stability, and the drag reduction of the SH surfaces was found.

  14. Drag reductions and the air-water interface stability of superhydrophobic surfaces in rectangular channel flow.

    PubMed

    Zhang, Jingxian; Yao, Zhaohui; Hao, Pengfei

    2016-11-01

    Flow in a rectangular channel with superhydrophobic (SH) top and bottom walls was investigated experimentally. Different SH surfaces, including hierarchical structured surfaces and surfaces with different micropost sizes (width and spacing) but the same solid fraction, were fabricated and measured. Pressure loss and flow rate in the channel with SH top and bottom walls were measured, with Reynolds number changing from 700 to 4700, and the corresponding friction factor for the SH surface was calculated. The statuses of the air plastron on different SH surfaces were observed during the experiment. In our experiment, compared with the experiment for the smooth surface, drag reductions were observed for all SH surfaces, with the largest drag reduction of 42.2%. It was found that the hierarchy of the microstructure can increase the drag reduction by decreasing the solid fraction and enhancing the stability of the air-water interface. With a fixed solid fraction, the drag reduction decreases as the post size (width and spacing) increases, due to the increasing curvature and instability effects of the air-water interface. A correlation parameter between the contact angle hysteresis, the air-water interface stability, and the drag reduction of the SH surfaces was found.

  15. Boundary layer flow of air past solid surfaces in the presence of rainfall

    NASA Astrophysics Data System (ADS)

    Smyrnaios, Dimitris N.; Pelekasis, Nikolaos A.; Tsamopoulos, John A.

    2000-12-01

    The steady two-dimensional laminar flow of an air stream, flowing past a solid surface at high Reynolds number, is examined in the presence of rainfall. As raindrops sediment on the surface they coalesce and form a continuous water film that flows due to shear, pressure drop and gravity, in general. In the limit as the boundary layer and film thickness remain smaller than the radius of curvature of the surface a simplified lubrication-type formulation describes the flow field in the film, whereas the usual boundary layer formulation is applied in the gas phase. In the case of a flat plate and close to the leading edge, x [rightward arrow] 0, a piecewise-self-similar solution is obtained, according to which creeping flow conditions prevail in the film and its thickness grows like x3/4, whereas the Blasius solution is recovered in the air stream. Numerical solution of the governing equations in the two phases and for the entire range of distances from the leading edge, x = O(1), shows that the film thickness increases as the rainfall rate, r[dot above], increases or as the free-stream velocity, U[infty infinity], decreases and that the region of validity of the asymptotic result covers a wide range of the relevant problem parameters. In the case of flow past a NACA-0008 airfoil at zero angle of attack a Goldstein singularity may appear far downstream on the airfoil surface due to adverse pressure gradients, indicating flow reversal and eddy formation inside the liquid film, and, possibly, flow separation. However, when the effect of gravity becomes evident in the film flow, as the Froude number decreases, and provided gravity acts in such a way as to negate the effect of the adverse pressure gradient, the location of the singularity is displaced towards the trailing edge of the airfoil and the flow pattern resembles that for flow past a flat plate. The opposite happens when gravity is aligned with the adverse pressure gradient. In addition it was found that there

  16. On the impact of entrapped air in infiltration under ponding conditions: Part a: Preferential air flow path effects on infiltration

    NASA Astrophysics Data System (ADS)

    Weisbord, N.; Mizrahi, G.; Furman, A.

    2015-12-01

    Entrapped air effects on infiltration under ponding conditions could be important for massive infiltration of managed aquifer recharge or soil aquifer treatment. Earlier studies found that under ponding conditions air could reduce infiltration by 70-90%. Most studies have dealt with entrapped air effects when soil surface topography is flat. The objective of this study is to investigate the effects of: (1) irregular surface topography on preferential air flow path development; (2) preferential air flow path on infiltration; and (3) hydraulic head on infiltration when air is trapped. Column experiments were used to investigate these particular effects. A 140 cm deep and 30 cm wide column packed with silica sand was used under two boundary conditions: in the first, air can only escape vertically upward through the soil surface; in the second, air is free to escape. The surface was flooded with 13 liters of water, with ponding depth decreasing with time. Two soil surface conditions were tested: flat surface and irregular. It was found that in irregular surfaces, stable air flow through preferential paths was developed in the high altitude zones. Flat surface topography caused unstable air flow through random paths. Comparison between irregular and flat surface topography showed that the entrapped air pressure was lower and the infiltration rate was about 40% higher in the irregular surface topography than in the flat surface topography. No difference of infiltration rate between flat and irregular surface topography was observed when air was free to escape along the infiltration path. It was also found that at the first stage of infiltration, higher hydraulic heads caused higher entrapped air pressures and lower infiltration rates. In contrast, higher hydraulic head results in higher infiltration rate, when air was free to escape. Our results suggest that during ponding conditions: (1) preferential air flow paths develop at high surface zones of irregular topography

  17. Flow visualization and acoustic consequences of the air moving through a static model of the human larynx.

    PubMed

    Kucinschi, Bogdan R; Scherer, Ronald C; DeWitt, Kenneth J; Ng, Terry T M

    2006-06-01

    Flow visualization with smoke particles illuminated by a laser sheet was used to obtain a qualitative description of the air flow structures through a dynamically similar 7.5x symmetric static scale model of the human larynx (divergence angle of 10 deg, minimal diameter of 0.04 cm real life). The acoustic level downstream of the vocal folds was measured by using a condenser microphone. False vocal folds (FVFs) were included. In general, the glottal flow was laminar and bistable. The glottal jet curvature increased with flow rate and decreased with the presence of the FVFs. The glottal exit flow for the lowest flow rate showed a curved jet which remained laminar for all geometries. For the higher flow rates, the jet flow patterns exiting the glottis showed a laminar jet core, transitioning to vortical structures, and leading spatially to turbulent dissipation. This structure was shortened and tightened with an increase in flow rate. The narrow FVF gap lengthened the flow structure and reduced jet curvature via acceleration of the flow. These results suggest that laryngeal flow resistance and the complex jet flow structure exiting the glottis are highly affected by flow rate and the presence of the false vocal folds. Acoustic consequences are discussed in terms of the quadrupole- and dipole-type sound sources due to ordered flow structures.

  18. Assessment of the status of work zone air environment due to opencast coal mining.

    PubMed

    Ghose, M K; Majee, S R

    2002-07-01

    In India coal production will have to be increased to meat the energy demand at a very high rate. By 2000 AD the cool production from opencast (O/C) mining will rise to 250 Mt. which will be about 70%of the total coal production. The increasing trend of O/C mining leads to cause air pollution problem. A survey was conducted to assess the status of work zone air envimment due to opencast coal mining in Jharia Coalfield. Keeping in view of place of dust generation air quality monitoring stations were selected. Methodology adapted for sampling and analysis of air pollutants have been described. Four season data revealed that maximum concentration of SPM was observed at dragline section and the next high concentration was at haul roads. At all the locations SPM and RPM concentrations exceeded the permissible limits specified by Indian Pollution Control Board. Shift wise and location wise analysis for getting higher concentration of SO2 and NOx, have been discussed. Wind velocity and directions, mixing heights, ventilation coefficient of the area have been analyzed. Huge dust generation creates vision problem to HEMM operators. The methodology adopted may be utilised on industrial scale for various sites.

  19. Characterization of air temperature in modern ion chambers due to phantom geometry and ambient temperature changes.

    PubMed

    Saenz, Daniel L; Kirby, Neil; Gutiérrez, Alonso N

    2016-07-01

    of temperature in the phantom was deemed far more accurate than measurement in ambient air due to the air cavity thermally equilibrating with phantom temperature instead of the vented ambient air. Wait times of 3 and 2 min are needed for a cube and 7.5 cm slab phantom, respectively, to achieve 0.2% dosimetric accuracy (temperature accuracy of 0.5 °C). Chamber volume alone did not determine wait times, as a 0.3 cm(3) IC required a longer wait time than a Farmer chamber, suggesting wall thickness as an important variable as well.

  20. Fuel-Air Injection Effects on Combustion in Cavity-Based Flameholders in a Supersonic Flow

    DTIC Science & Technology

    2005-03-01

    FUEL-AIR INJECTION EFFECTS ON COMBUSTION IN CAVITY-BASED FLAMEHOLDERS IN A SUPERSONIC FLOW THESIS...Government. AFIT/GAE/ENY/05-M02 FUEL-AIR INJECTION EFFECTS ON COMBUSTION IN CAVITY-BASED FLAMEHOLDERS IN A SUPERSONIC FLOW THESIS Presented to...AIR INJECTION EFFECTS ON COMBUSTION IN CAVITY-BASED FLAMEHOLDERS IN A SUPERSONIC FLOW William H. Allen Jr., BSME Captain, USAF

  1. Experimental Study on Impact Load on a Dam Due to Debris Flow

    Treesearch

    lwao Miyoshi

    1991-01-01

    When a dam is struck by mud or debris flow, it is put under a great impact load and sometimes is destroyed. To prevent such destruction, it is important to perform basic research about the impact load on a dam due to debris flow. Thus, we have made an experimental study and tried to establish a method to estimate such a impact load on the dam. The experiment was...

  2. Fluid flows due to earthquakes with reference to Yucca Mountain, Nevada

    SciTech Connect

    Davies, J.B.

    1993-05-01

    Yucca Mountain geohydrology is dominated by a deep water table in volcanic tuffa beds which are cut by numerous faults. Certain zones in these tuffas and most of the fault apertures are filled with a fine-grained calcitic cement. Earthquakes have occured in this region with the most recent being of magnitude 5.6 and at a distance of about 20 km. Earthquakes in western U.S.A. have been observed to cause fluid flows through and out of the crust of the Earth. These flows are concentrated along the faults with normal faulting producing the largest flows. An earthquake produces rapid pressure changes at and below the ground surface, thereby forcing flows of gas, water, slurries and dissolved salts. In order to examine the properties of flows produced by earthquakes, we simulate the phenomena using computer-based modeling. We investigate the effects of adults and high permeability zones on the pattern of flows induced by the earthquake. We demonstrate that faults act as conduits to the surface and that the higher the permeability of a zone, the more the flows will concentrate there. Numerical estimates of flow rates from these simulations compare favorably with data from observed flows due to earthquakes. Simple volumetric arguments demonstrate the ease with which fluids from the deep water table can reach the surface along fault conduits.

  3. Large Eddy simulation of turbulent hydrogen-fuelled supersonic combustion in an air cross-flow

    NASA Astrophysics Data System (ADS)

    Ingenito, A.; Cecere, D.; Giacomazzi, E.

    2013-09-01

    The main aim of this article is to provide a theoretical understanding of the physics of supersonic mixing and combustion. Research in advanced air-breathing propulsion systems able to push vehicles well beyond is of interest around the world. In a scramjet, the air stream flow captured by the inlet is decelerated but still maintains supersonic conditions. As the residence time is very short , the study of an efficient mixing and combustion is a key issue in the ongoing research on compressible flows. Due to experimental difficulties in measuring complex high-speed unsteady flowfields, the most convenient way to understand unsteady features of supersonic mixing and combustion is to use computational fluid dynamics. This work investigates supersonic combustion physics in the Hyshot II combustion chamber within the Large Eddy simulation framework. The resolution of this turbulent compressible reacting flow requires: (1) highly accurate non-dissipative numerical schemes to properly simulate strong gradients near shock waves and turbulent structures away from these discontinuities; (2) proper modelling of the small subgrid scales for supersonic combustion, including effects from compressibility on mixing and combustion; (3) highly detailed kinetic mechanisms (the Warnatz scheme including 9 species and 38 reactions is adopted) accounting for the formation and recombination of radicals to properly predict flame anchoring. Numerical results reveal the complex topology of the flow under investigation. The importance of baroclinic and dilatational effects on mixing and flame anchoring is evidenced. Moreover, their effects on turbulence-scale generation and the scaling law are analysed.

  4. Some Effects of Air Flow on the Penetration and Distribution of Oil Sprays

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Beardsley, E G

    1929-01-01

    Tests were made to determine the effects of air flow on the characteristics of fuel sprays from fuel injection valves. Curves and photographs are presented showing the airflow throughout the chamber and the effects of the air flow on the fuel spray characteristics. It was found that the moving air had little effect on the spray penetration except with the 0.006 inch orifice. The moving air did, however, affect the oil particles on the outside of the spray cone. After spray cut-off, the air flow rapidly distributed the atomized fuel throughout the spray chamber.

  5. Global premature mortality due to anthropogenic outdoor air pollution and the contribution of past climate change

    NASA Astrophysics Data System (ADS)

    Silva, Raquel A.; West, J. Jason; Zhang, Yuqiang; Anenberg, Susan C.; Lamarque, Jean-François; Shindell, Drew T.; Collins, William J.; Dalsoren, Stig; Faluvegi, Greg; Folberth, Gerd; Horowitz, Larry W.; Nagashima, Tatsuya; Naik, Vaishali; Rumbold, Steven; Skeie, Ragnhild; Sudo, Kengo; Takemura, Toshihiko; Bergmann, Daniel; Cameron-Smith, Philip; Cionni, Irene; Doherty, Ruth M.; Eyring, Veronika; Josse, Beatrice; MacKenzie, I. A.; Plummer, David; Righi, Mattia; Stevenson, David S.; Strode, Sarah; Szopa, Sophie; Zeng, Guang

    2013-09-01

    Increased concentrations of ozone and fine particulate matter (PM2.5) since preindustrial times reflect increased emissions, but also contributions of past climate change. Here we use modeled concentrations from an ensemble of chemistry-climate models to estimate the global burden of anthropogenic outdoor air pollution on present-day premature human mortality, and the component of that burden attributable to past climate change. Using simulated concentrations for 2000 and 1850 and concentration-response functions (CRFs), we estimate that, at present, 470 000 (95% confidence interval, 140 000 to 900 000) premature respiratory deaths are associated globally and annually with anthropogenic ozone, and 2.1 (1.3 to 3.0) million deaths with anthropogenic PM2.5-related cardiopulmonary diseases (93%) and lung cancer (7%). These estimates are smaller than ones from previous studies because we use modeled 1850 air pollution rather than a counterfactual low concentration, and because of different emissions. Uncertainty in CRFs contributes more to overall uncertainty than the spread of model results. Mortality attributed to the effects of past climate change on air quality is considerably smaller than the global burden: 1500 (-20 000 to 27 000) deaths yr-1 due to ozone and 2200 (-350 000 to 140 000) due to PM2.5. The small multi-model means are coincidental, as there are larger ranges of results for individual models, reflected in the large uncertainties, with some models suggesting that past climate change has reduced air pollution mortality.

  6. Mechanistic understanding of monosaccharide-air flow battery electrochemistry

    NASA Astrophysics Data System (ADS)

    Scott, Daniel M.; Tsang, Tsz Ho; Chetty, Leticia; Aloi, Sekotilani; Liaw, Bor Yann

    Recently, an inexpensive monosaccharide-air flow battery configuration has been demonstrated to utilize a strong base and a mediator redox dye to harness electrical power from the partial oxidation of glucose. Here the mechanistic understanding of glucose oxidation in this unique glucose-air power source is further explored by acid-base titration experiments, 13C NMR, and comparison of results from chemically different redox mediators (indigo carmine vs. methyl viologen) and sugars (fructose vs. glucose) via studies using electrochemical techniques. Titration results indicate that gluconic acid is the main product of the cell reaction, as supported by evidence in the 13C NMR spectra. Using indigo carmine as the mediator dye and fructose as the energy source, an abiotic cell configuration generates a power density of 1.66 mW cm -2, which is greater than that produced from glucose under similar conditions (ca. 1.28 mW cm -2). A faster transition from fructose into the ene-diol intermediate than from glucose likely contributed to this difference in power density.

  7. Imaging based optofluidic air flow meter with polymer interferometers defined by soft lithography.

    PubMed

    Song, Wuzhou; Psaltis, Demetri

    2010-08-02

    We present an optofluidic chip with integrated polymer interferometers for measuring both the microfluidic air pressure and flow rate. The chip contains a microfluidic circuit and optical cavities on a polymer which was defined by soft lithography. The pressure can be read out by imaging the interference patterns of the cavities. The air flow rate was then calculated from the differential pressure across a microfluidic Venturi circuit. Air flow rate measurement in the range of 0-2mg/second was demonstrated. This device provides a simple and versatile way for in situ measuring the microscale air pressure and flow on chip.

  8. Real-Time Aerodynamic Parameter Estimation without Air Flow Angle Measurements

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    2010-01-01

    A technique for estimating aerodynamic parameters in real time from flight data without air flow angle measurements is described and demonstrated. The method is applied to simulated F-16 data, and to flight data from a subscale jet transport aircraft. Modeling results obtained with the new approach using flight data without air flow angle measurements were compared to modeling results computed conventionally using flight data that included air flow angle measurements. Comparisons demonstrated that the new technique can provide accurate aerodynamic modeling results without air flow angle measurements, which are often difficult and expensive to obtain. Implications for efficient flight testing and flight safety are discussed.

  9. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    NASA Astrophysics Data System (ADS)

    Döll, P.; Fiedler, K.; Zhang, J.

    2009-12-01

    Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes, in particular of flow variability, by water withdrawals and dams/reservoirs. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams around the year 2000, as well as naturalized discharge without this type of human interference. Compared to naturalized conditions, long-term average global discharge into oceans and internal sinks has decreased by 2.7% due to water withdrawals, and by 0.8% due to dams. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months) have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland), respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and reservoirs, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas downstream of reservoirs where consumptive water use is low. The impact of reservoirs is likely underestimated by our study as small reservoirs are not taken into account. Areas most affected by anthropogenic river flow alterations are the Western and Central USA, Mexico, the

  10. Measurement of HOx• production rate due to radon decay in air

    SciTech Connect

    Ding, Huiling

    1993-08-01

    Radon in indoor air may cause the exposure of the public to excessive radioactivity. Radiolysis of water vapor in indoor air due to radon decay could produce (•OH and HO2 •) that may convert atmospheric constituents to compounds of lower vapor pressure. These lower vapor pressure compounds might then nucleate to form new particles in the indoor atmosphere. Chemical amplification was used to determine HOx• production rate in indoor air caused by radon decay. Average HOx• production rate was found to be (4.31±0.07) x 105 HOx• per Rn decay per second (Bq) 3.4 to 55.0% at 22C. This work provided G(HOx•)-value, 7.86±0.13 No./100 eV in air by directly measuring [HOx•] formed from the radiolysis procedure. This G value implies that HOx• produced by radon decay in air might be formed by multiple processes and may be result of positive ion-molecule reactions, primary radiolysis, and radical reactions. There is no obvious relation between HOx• production rate and relative humidity. A laser-induced fluorescence (LIF) system has been used for •OH production rate measurement; it consists of an excimer laser, a dye laser, a frequency doubler, a gaseous fluorescence chamber, and other optical and electronic parts. This system needs to be improved to eliminate the interferences of light scattering and artificial •OH produced from the photolysis of O3/H2O.

  11. Electro-Hydrodynamics and Kinetic Modeling of Dry and Humid Air Flows Activated by Corona Discharges

    NASA Astrophysics Data System (ADS)

    P. Sarrette, J.; Eichwald, O.; Marchal, F.; Ducasse, O.; Yousfi, M.

    2016-05-01

    The present work is devoted to the 2D simulation of a point-to-plane Atmospheric Corona Discharge Reactor (ACDR) powered by a DC high voltage supply. The corona reactor is periodically crossed by thin mono filamentary streamers with a natural repetition frequency of some tens of kHz. The study compares the results obtained in dry air and in air mixed with a small amount of water vapour (humid air). The simulation involves the electro-dynamics, chemical kinetics and neutral gas hydrodynamics phenomena that influence the kinetics of the chemical species transformation. Each discharge lasts about one hundred of a nanosecond while the post-discharge occurring between two successive discharges lasts one hundred of a microsecond. The ACDR is crossed by a lateral dry or humid air flow initially polluted with 400 ppm of NO. After 5 ms, the time corresponding to the occurrence of 50 successive discharge/post-discharge phases, a higher NO removal rate and a lower ozone production rate are found in humid air. This change is due to the presence of the HO2 species formed from the H primary radical in the discharge zone.

  12. Numerical modelling of convective heat transport by air flow in permafrost talus slopes

    NASA Astrophysics Data System (ADS)

    Wicky, Jonas; Hauck, Christian

    2017-06-01

    Talus slopes are a widespread geomorphic feature in the Alps. Due to their high porosity a gravity-driven internal air circulation can be established which is forced by the gradient between external (air) and internal (talus) temperature. The thermal regime is different from the surrounding environment, leading to the occurrence of permafrost below the typical permafrost zone. This phenomenon has mainly been analysed by field studies and only few explicit numerical modelling studies exist. Numerical simulations of permafrost sometimes use parameterisations for the effects of convection but mostly neglect the influence of convective heat transfer in air on the thermal regime. In contrast, in civil engineering many studies have been carried out to investigate the thermal behaviour of blocky layers and to improve their passive cooling effect. The present study further develops and applies these concepts to model heat transfer in air flows in a natural-scale talus slope. Modelling results show that convective heat transfer has the potential to develop a significant temperature difference between the lower and the upper parts of the talus slope. A seasonally alternating chimney-effect type of circulation develops. Modelling results also show that this convective heat transfer leads to the formation of a cold reservoir in the lower part of the talus slope, which can be crucial for maintaining the frozen ground conditions despite increasing air temperatures caused by climate change.

  13. Reduction of erosion in elbows due to flow modifications: Final report, Phase 1. [Elbows

    SciTech Connect

    Johnson, E.K.; Means, K.H.; Eyler, R.L.; Holtzworth, J.D.

    1987-11-01

    The objective of this project is to investigate the concept of flow-field modification as a method for reducing erosion in bends (elbows) used in pneumatic transport systems. Flow field modifications were primarily accomplished by injecting air at selected locations within the bends. Part I of this project shows the feasibility of the concept. Part II of this project will include further experiments and analysis, leading to a design methodology for incorporating this concept into piping systems. This report represents the final report for Part I of this project. This report contains a survey of the literature dealing with the erosion in bends (elbows) and the fundamental subjects of erosion and two-phase, gas-solids, flow. Based on this literature survey, a pneumatic transport test loop was constructed. Several bend designs were tested, using sand, under a variety of operating conditions. The results of this exploratory effort indicate that modifying the flow field in a bend with jets may: (1) decrease erosion; (2) change the erosion pattern with the same amount of erosion; or (3) significantly increase the erosion process. Data indicate that the erosion rate may be reduced by low-velocity jets for high phase-density flow. Apparently the interaction of jets with dilute phase-density flow tends to accelerate the erosion process. It is recommended that the project be continued in order to more fully understand the process and its capabilities to solve the difficult technical problem of erosion in bends (elbows).

  14. A study of the accuracy of neutrally buoyant bubbles used as flow tracers in air

    NASA Technical Reports Server (NTRS)

    Kerho, Michael F.

    1993-01-01

    Research has been performed to determine the accuracy of neutrally buoyant and near neutrally buoyant bubbles used as flow tracers in air. Theoretical, computational, and experimental results are presented to evaluate the dynamics of bubble trajectories and factors affecting their ability to trace flow-field streamlines. The equation of motion for a single bubble was obtained and evaluated using a computational scheme to determine the factors which affect a bubble's trajectory. A two-dimensional experiment was also conducted to experimentally determine bubble trajectories in the stagnation region of NACA 0012 airfoil at 0 deg angle of attack using a commercially available helium bubble generation system. Physical properties of the experimental bubble trajectories were estimated using the computational scheme. These properties included the density ratio and diameter of the individual bubbles. the helium bubble system was then used to visualize and document the flow field about a 30 deg swept semispan wing with simulated glaze ice. Results were compared to Navier-Stokes calculations and surface oil flow visualization. The theoretical and computational analysis have shown that neutrally buoyant bubbles will trace even the most complex flow patterns. Experimental analysis revealed that the use of bubbles to trace flow patterns should be limited to qualitative measurements unless care is taken to ensure neutral buoyancy. This is due to the difficulty in the production of neutrally buoyant bubbles.

  15. Gas and liquid measurements in air-water bubbly flows

    SciTech Connect

    Zhou, X.; Doup, B.; Sun, X.

    2012-07-01

    Local measurements of gas- and liquid-phase flow parameters are conducted in an air-water two-phase flow loop. The test section is a vertical pipe with an inner diameter of 50 mm and a height of 3.2 m. The measurements are performed at z/D = 10. The gas-phase measurements are performed using a four-sensor conductivity probe. The data taken from this probe are processed using a signal processing program to yield radial profiles of the void fraction, bubble velocity, and interfacial area concentration. The velocity measurements of the liquid-phase are performed using a state-of-the-art Particle Image Velocimetry (PIV) system. The raw PIV images are acquired using fluorescent particles and an optical filtration device. Image processing is used to remove noise in the raw PIV images. The statistical cross correlation is introduced to determine the axial velocity field and turbulence intensity of the liquid-phase. Measurements are currently being performed at z/D = 32 to provide a more complete data set. These data can be used for computational fluid dynamic model development and validation. (authors)

  16. Benefits of mitigated ambient air quality due to transportation control on childhood asthma hospitalization during the 2002 summer Asian games in Busan, Korea.

    PubMed

    Lee, Jong-Tae; Son, Ji-Young; Cho, Yong-Sung

    2007-08-01

    The objective of this study is to see whether there were any health benefits of mitigated air pollution concentration due to reduced traffic flow during a citywide intervention for the 2002 Summer Asian Games. Relative risks of hospitalization for childhood asthma during the post-Asian Game period compared with the baseline period were estimated using a time-series analysis of the generalized additive Poisson model. Fourteen consecutive days of traffic volume control in Busan during the Games reduced all regulated air pollutant levels by 1-25%. The estimated relative risk of hospitalization during the post-Games period over the baseline period was 0.73 (95% confidence interval [CI] = 0.49, 1.11). We observed that this reduced air pollution was unique in 2002 when the traffic volume reduction program was applied during the Games period. This empirical data provides epidemiologic evidence of the health benefits resulting from environmental interventions to reduce ambient air pollution.

  17. Design and analysis of Air flow duct for improving the thermal performance of disc brake rotor

    NASA Astrophysics Data System (ADS)

    Raja, T.; Mathiselvan, G.; Sreenivasulureddy, M.; Goldwin Xavier, X.

    2017-05-01

    safety in automotive engineering has been considered as a number one priority in development of new vehicle. A brake system is one of the most critical systems in the vehicle, without which the vehicle will put a passenger in an unsafe position. Temperature distribution on disc rotor brake and the performance brake of disc rotor is influenced by the air flow around the disc rotor. In this paper, the effect of air flow over the disc rotor is analyzed using the CFD software. The air flow over the disc rotor is increased by using a duct to supply more air flow over the disc rotor. The duct is designed to supply more air to the rotor surface and it can be placed in front of the vehicle for better performance. Increasing the air flow around the rotor will maximize the heat convection from the rotor surface. The rotor life and the performance can be improved.

  18. The existence of longitudinal vortices in the flow of air above an air/water interface

    NASA Astrophysics Data System (ADS)

    Kou, J.; Saylor, J. R.

    2009-11-01

    Many researchers have observed the formation of longitudinal vortices in boundary layers developing over heated solid surfaces. In the present work, such vortices were observed in an air boundary layer developing over a heated water surface. The existence of these vortices was documented via infrared imaging of the water surface, which showed a consistent pattern of hot and cold streaks, coinciding with the vortex position. These vortices were also visualized through smoke injected into the air-side flow. The onset position Xc and lateral vortex spacing λ were investigated for a range of wind speeds (0.1 - 1 m/s) and air/water temperature differences (26 - 42 ^oC). Plots of Xc/λ versus the Reynolds number exhibit power-law behavior similar to that of prior work on boundary layers over heated solid surfaces. However, plots of Xc/λ versus the Grashof number show significant differences from the power-law behavior observed for heated solid plates. A theory explaining the similarity and difference between the present results and those for heated solid plates is discussed which is based on differences in the thermal boundary conditions.

  19. A semi-analytical solution for flow due to streambed recharge to an unconfined aquifer with considering unsaturated flow

    NASA Astrophysics Data System (ADS)

    Chia-Hao, C.; Yeh, H. D.

    2016-12-01

    Previous models for groundwater recharge or infiltration problems considered either saturated flow or unsaturated flow in unconfined aquifers. However, it is expected that the recharge /infiltration has substantial effects on the hydraulic head in unsaturated zones and saturated aquifers in reality. This study develops a mathematical model to depict unsaturated and saturated flows induced by stream recharge from the streambed to the unsaturated zone above an unconfined aquifer of infinitely horizontal extent. The model consists of Richards' equation for flow in the unsaturated zone and groundwater flow equation for the saturated aquifer. The Gardner model is employed to describe the water content and relative permeability related to an unsaturated exponent. The model is nonlinear due to Richards' equation and the moving water table on the top of the unconfined aquifer. It is therefore linearized based on the perturbation theory. The solution of the linearized model is derived by the methods of Laplace transform and Fourier cosine transform. With the solution, the effects of hydraulic parameters on the flows are investigated. The present solution has good efficiency in calculations and is a useful tool to provide predictions of spatiotemporal head distributions in groundwater recharge problems for engineering applications.

  20. Asymmetrical reverse vortex flow due to induced-charge electro-osmosis around carbon stacking structures

    NASA Astrophysics Data System (ADS)

    Sugioka, Hideyuki

    2011-05-01

    Broken symmetry of vortices due to induced-charge electro-osmosis (ICEO) around stacking structures is important for the generation of a large net flow in a microchannel. Following theoretical predictions in our previous study, we herein report experimental observations of asymmetrical reverse vortex flows around stacking structures of carbon posts with a large height (~110 μm) in water, prepared by the pyrolysis of a photoresist film in a reducing gas. Further, by the use of a coupled calculation method that considers boundary effects precisely, the experimental results, except for the problem of anomalous flow reversal, are successfully explained. That is, unlike previous predictions, the precise calculations here show that stacking structures accelerate a reverse flow rather than suppressing it for a microfluidic channel because of the deformation of electric fields near the stacking portions; these structures can also generate a large net flow theoretically in the direction opposite that of a previous prediction for a standard vortex flow. Furthermore, by solving the one-dimensional Poisson-Nernst-Plank (PNP) equations in the presence of ac electric fields, we find that the anomalous flow reversal occurs by the phase retardation between the induced diffuse charge and the tangential electric field. In addition, we successfully explain the nonlinearity of the flow velocity on the applied voltage by the PNP analysis. In the future, we expect to improve the pumping performance significantly by using stacking structures of conductive posts along with a low-cost process.

  1. RADIOLOGICAL RELEASES DUE TO AIR AND SILICA DUST ACTIVATION IN EMPLACEMENT DRIFTS

    SciTech Connect

    J.S. Tang

    2003-05-07

    The purpose of this calculation is to determine the quantity and significance of annual Monitored Geologic Repository (MGR) subsurface normal radiological releases due to neutron activation of air and silica dust in emplacement drifts. This calculation includes the following items: (1) Calculate activation of ventilation airflow through emplacement drifts to quantify radioactive gaseous releases; and (2) Calculate the bounding potential activated silica dust concentration and releases. The sources of silica dust may arise from air supply to emplacement drifts as well as host rock around emplacement drifts. For this calculation, the source of dust is conservatively assumed to be the host rock (Assumption 3.6), which is subject to long-term neutron exposure resulting in saturated radioactivity. The scope of this calculation is limited to releases from activated air and silica dust only, excluding natural radioactive releases such as radon or releases from defective waste packages (breached or contaminated). This work supports the repository ventilation system design and Preclosure Safety Analysis. This includes MGR items classified as Quality Level 1, for example, the Uncanistered Spent Nuclear Fuel Waste Package (CRWMS M&O [Civilian Radioactive Waste Management and Operation Contractor] 1999a, page 7). Therefore, this calculation is subject to the requirements of the ''Quality Assurance Requirements and Description'' (DOE [U.S. Department of Energy] 2003). The performance of the calculation and development of this document are carried out in accordance with AP-3.12Q, ''Design Calculation and Analyses'' and LP-3.30Q-BSC, ''Hazards Analysis System''.

  2. Dynamic analysis of a BLDC motor with mechanical and electromagnetic interaction due to air gap variation

    NASA Astrophysics Data System (ADS)

    Im, Hyungbin; Yoo, Hong Hee; Chung, Jintai

    2011-04-01

    In this study, the dynamic behaviors of a BLDC motor are analyzed, when the motor undergoes mechanical and electromagnetic interaction due to an air gap variation between the stator and rotor. When considering the air gap variation caused by the translational motion of the rotor relative to the stator, the kinetic and potential energies, Rayleigh dissipation function, and the magnetic coenergy are expressed in terms of the rotor displacements and stator currents. With these energies and function, new equations of motion are derived using Lagrange's equation. The equations for the proposed model are nonlinear equations in which the displacements and currents are coupled. The time responses for the displacements and currents are computed for the proposed and previous models. Furthermore, the effects of rotor eccentricity are also investigated. It is found that, when the air gap varies with time, the time responses for the proposed and previous models have small differences in the stator currents, electromagnetic torques, and rotating speeds. However, the time responses have large differences in the rotor displacements. Therefore, this paper claims that the proposed model describes the dynamic behaviors of the motor more accurately than the previous model. It is also shown that rotor eccentricity increases the stator current period and the electromagnetic torque, while it decreases the rotating speed of the rotor.

  3. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... meters. 1065.240 Section 1065.240 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 1065.240 Dilution air and diluted exhaust flow meters. (a) Application. Use a diluted exhaust flow meter to determine instantaneous diluted exhaust flow rates or total diluted exhaust flow over a...

  4. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... meters. 1065.240 Section 1065.240 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 1065.240 Dilution air and diluted exhaust flow meters. (a) Application. Use a diluted exhaust flow meter to determine instantaneous diluted exhaust flow rates or total diluted exhaust flow over a...

  5. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... meters. 1065.240 Section 1065.240 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 1065.240 Dilution air and diluted exhaust flow meters. (a) Application. Use a diluted exhaust flow meter to determine instantaneous diluted exhaust flow rates or total diluted exhaust flow over a...

  6. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... meters. 1065.240 Section 1065.240 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 1065.240 Dilution air and diluted exhaust flow meters. (a) Application. Use a diluted exhaust flow meter to determine instantaneous diluted exhaust flow rates or total diluted exhaust flow over a...

  7. 40 CFR 1065.240 - Dilution air and diluted exhaust flow meters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... meters. 1065.240 Section 1065.240 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 1065.240 Dilution air and diluted exhaust flow meters. (a) Application. Use a diluted exhaust flow meter to determine instantaneous diluted exhaust flow rates or total diluted exhaust flow over a...

  8. CNT Based Artificial Hair Sensors for Predictable Boundary Layer Air Flow Sensing (Postscript)

    DTIC Science & Technology

    2016-11-07

    ABSTRACT (Maximum 200 words) While numerous flow sensor architectures mimic the natural cilia of crickets, locusts, bats, and fish, the prediction...magnitude variability in both sensitivity and CNT compressive modulus. 15. SUBJECT TERMS flow sensor architectures ; hair sensor; piezoresistive...Boundary Layer Air Flow Sensing Keith A. Slinker,* Corey Kondash, Benjamin T. Dickinson, and Jeffery W. Baur While numerous flow sensor architectures

  9. Air pollutants and hospitalization due to pneumonia among children. An ecological time series study.

    PubMed

    Tuan, Tassia Soldi; Venâncio, Taís Siqueira; Nascimento, Luiz Fernando Costa

    2015-01-01

    Exposure to air pollutants is one of the factors responsible for hospitalizations due to pneumonia among children. This has considerable financial cost, along with social cost. A study to identify the role of this exposure in relation to hospital admissions due to pneumonia among children up to 10 years of age was conducted. Ecological time series study using data from São José dos Campos, Brazil. Daily data on hospitalizations due to pneumonia and on the pollutants CO, O3, PM10 and SO2, temperature and humidity in São José dos Campos, in 2012, were analyzed. A generalized additive model of Poisson's regression was used. Relative risks for hospitalizations due to pneumonia, according to lags of 0-5 days, were estimated. The population-attributable fraction, number of avoidable hospitalizations and cost savings from avoidable hospitalizations were calculated. There were 539 admissions. Exposure to CO and O3 was seen to be associated with hospitalizations, with risks of 1.10 and 1.15 on the third day after exposure to increased CO concentration of 200 ppb and ozone concentration of 20 µg/m3. Exposure to the pollutants of particulate matter and sulfur dioxide were not shown to be associated with hospitalizations. Decreases in CO and ozone concentrations could lead to 49 fewer hospitalizations and cost reductions of R$ 39,000.00. Exposure to certain air pollutants produces harmful effects on children's health, even in a medium-sized city. Public policies to reduce emissions of these pollutants need to be implemented.

  10. Global-scale analysis of river flow alterations due to water withdrawals and reservoirs

    NASA Astrophysics Data System (ADS)

    Döll, P.; Fiedler, K.; Zhang, J.

    2009-07-01

    Global-scale information on natural river flows and anthropogenic river flow alterations is required to identify areas where aqueous ecosystems are expected to be strongly degraded. Such information can support the identification of environmental flow guidelines and a sustainable water management that balances the water demands of humans and ecosystems. This study presents the first global assessment of the anthropogenic alteration of river flow regimes by water withdrawals and dams, focusing in particular on the change of flow variability. Six ecologically relevant flow indicators were quantified using an improved version of the global water model WaterGAP. WaterGAP simulated, with a spatial resolution of 0.5 degree, river discharge as affected by human water withdrawals and dams, as well as naturalized discharge without this type of human interference. Mainly due to irrigation, long-term average river discharge and statistical low flow Q90 (monthly river discharge that is exceeded in 9 out of 10 months) have decreased by more than 10% on one sixth and one quarter of the global land area (excluding Antarctica and Greenland), respectively. Q90 has increased significantly on only 5% of the land area, downstream of reservoirs. Due to both water withdrawals and dams, seasonal flow amplitude has decreased significantly on one sixth of the land area, while interannual variability has increased on one quarter of the land area mainly due to irrigation. It has decreased on only 8% of the land area, in areas with little consumptive water use that are downstream of dams. Areas most affected by anthropogenic river flow alterations are the western and central USA, Mexico, the western coast of South America, the Mediterranean rim, Southern Africa, the semi-arid and arid countries of the Near East and Western Asia, Pakistan and India, Northern China and the Australian Murray-Darling Basin, as well as some Arctic rivers. Due to a large number of uncertainties related e.g. to the

  11. Observational evidence of increased tropical rainfall due to air passage over forests

    NASA Astrophysics Data System (ADS)

    Spracklen, D. V.; Arnold, S. R.; Taylor, C.

    2012-12-01

    Vegetation affects precipitation patterns through altering moisture, energy and trace-gas fluxes between the surface and atmosphere. Climate model studies typically predict that large-scale deforestation results in reduced regional precipitation. Observational studies that have attempted to confirm these modelling predictions have yielded conflicting results likely due to the large temporal and spatial variability in precipitation masking land-cover induced changes. Here we explore the effect of tropical vegetation on precipitation using satellite remote sensed observations of precipitation from the tropical Rainfall Measuring Mission (TRMM) and other satellites combined (TRMM3B42) and leaf area index (LAI) from the Moderate Resolution Imaging Spectroradiometer (MODIS). We combine these observations with a Lagrangian atmospheric transport model which we use to describe daily variability in tropical atmospheric transport patterns. We calculate cumulative exposure of air masses to tropical vegetation and explore relationships between this exposure and observed precipitation. We find that for large regions of the tropics air that has experienced a large cumulative exposure to vegetation in the preceding few days produces at least twice as much rain as air that has little exposure. To understand potential mechanisms behind this relationship we explore the atmospheric water budget along analysed back trajectories. We constrain the water budget using specific humidity from analysed meteorological fields combined with global land-surface model output of evapotranspiration (ET). We find that ET in air masses with large exposure to vegetation maintains atmospheric moisture sufficiently to explain observed relationships with precipitation. We combine these empirical relationships with a business-as-usual scenario of Amazonian deforestation to estimate impacts on future precipitation.

  12. Streaming flow due to a quartz tuning fork oscillating in normal and superfluid 4He

    NASA Astrophysics Data System (ADS)

    Duda, D.; La Mantia, M.; Skrbek, L.

    2017-07-01

    We visualize the streaming flow due to a rapidly oscillating quartz tuning fork, in both normal He I and superfluid He II, by following the flow-induced motions of relatively small particles suspended in the liquid. Over the investigated temperature range, between 1.2 and 2.3 K, at the experimentally probed length scales, the streaming patterns observed in He II appear identical to those seen in He I and are very similar to those reported to occur in water, outside the Stokes boundary layer. The outcome strongly supports the view that, at scales larger than the quantum length scale of the flow, the mean distance between quantized vortices, mechanically forced turbulent coflows of He II behave classically, due to the dynamical locking of the two components of superfluid 4He by the action of the mutual friction force.

  13. Impacts on ambient air quality due to flaring activities in one of Oman's oilfields.

    PubMed

    Abdul-Wahab, Sabah; Ali, Sappurd; Sardar, Sabir; Irfan, Naseem

    2012-01-01

    This work was conducted to assess the impacts on workplace and ambient air quality due to release of sulfur dioxide (SO(2)) into the atmosphere at Al-Noor production station, located in southern desert of Sultanate of Oman. The SO(2) is released because of oxidation of H(2)S to SO(2) on flaring of H(2)S rich off gas at the Al-Noor. In the first phase of the study, CALPUFF modeling system was used to predict the ground level concentrations of SO(2) emissions from the flare stacks. The evaluation of the modeling system was carried out by comparing the predicted results with that of the measured. In the second stage of the study, the estimated results were compared with the air quality standards/guidelines set by Omani regulatory authorities as well as by World Health Organization (WHO). It was concluded on the basis of current study that the sensitive individuals in the workplace of the Al-Noor could experience adverse health effects due to short-term exposure of SO(2).

  14. A Modeling of Cerebral Blood Flow Changes due to Head Motion for fNIRS

    NASA Astrophysics Data System (ADS)

    Takahashi, Kosuke; Tanaka, Takayuki; Nara, Hiroyuki; Kaneko, Shun'ichi; Inoue, Masao; Shimizu, Shunji; Kojima, Satoru

    2013-04-01

    A method is proposed for measuring brain activity during exercises involving head motion by using functional near-infrared spectroscopy (fNIRS), which investigates cerebral hemodynamics. Obtaining measurements during exercise is difficult because cerebral blood flow changes due to the head motion component (HMC), in addition to neural activity. HMC is an undesirable artifact in the measurement of hemodynamic response caused by neural activity, and as such, it must be estimated and eliminated. In our experiments, cerebral blood flow and head motion were measured during repeated passive forward bending of the subjects. Head motion was measured by 3-D motion capture, and HMC was estimated by deriving a relation between head motion and cerebral blood flow, where the pitch angle was found to be suitable for estimating HMC. In this research, an assumption was made that cerebral blood flow caused by neural activity and that caused by postural change were additive, and thus HMC was eliminated by subtraction.

  15. Nonlinear saturation of the Rayleigh instability due to oscillatory flow in a liquid-lined tube

    NASA Astrophysics Data System (ADS)

    Halpern, David; Grotberg, James B.

    2003-10-01

    In this paper, the stability of core annular flows consisting of two immiscible fluids in a cylindrical tube with circular cross-section is examined. Such flows are important in a wide range of industrial and biomedical applications. For example, in secondary oil recovery, water is pumped into the well to displace the remaining oil. It is also of relevance in the lung, where a thin liquid film coats the inner surface of the small airways of the lungs. In both cases, the flow is influenced by a surface-tension instability, which may induce the breakup of the core fluid into short plugs, reducing the efficiency of the oil recovery, or blocking the passage of air in the lung thus inducing airway closure. We consider the stability of a thin film coating the inner surface of a rigid cylindrical tube with the less viscous fluid in the core. For thick enough films, the Rayleigh instability forms a liquid bulge that can grow to eventually create a plug blocking the tube. The analysis explores the effect of an oscillatory core flow on the interfacial dynamics and particularly the nonlinear stabilization of the bulge. The oscillatory core flow exerts tangential and normal stresses on the interface between the two fluids that are simplified by uncoupling the core and film analyses in the thin-film high-frequency limit of the governing equations. Lubrication theory is used to derive a nonlinear evolution equation for the position of the air liquid interface which includes the effects of the core flow. It is shown that the core flow can prevent plug formation of the more viscous film layer by nonlinear saturation of the capillary instability. The stabilization mechanism is similar to that of a reversing butter knife, where the core shear wipes the growing liquid bulge back on to the tube wall during the main tidal volume stroke, but allows it to grow back as the stoke and shear turn around. To be successful, the leading film thickness ahead of the bulge must be smaller than the

  16. SPATIAL DAMPING OF PROPAGATING KINK WAVES DUE TO RESONANT ABSORPTION: EFFECT OF BACKGROUND FLOW

    SciTech Connect

    Soler, R.; Goossens, M.; Terradas, J.

    2011-06-20

    Observations show the ubiquitous presence of propagating magnetohydrodynamic (MHD) kink waves in the solar atmosphere. Waves and flows are often observed simultaneously. Due to plasma inhomogeneity in the direction perpendicular to the magnetic field, kink waves are spatially damped by resonant absorption. The presence of flow may affect the wave spatial damping. Here, we investigate the effect of longitudinal background flow on the propagation and spatial damping of resonant kink waves in transversely nonuniform magnetic flux tubes. We combine approximate analytical theory with numerical investigation. The analytical theory uses the thin tube (TT) and thin boundary (TB) approximations to obtain expressions for the wavelength and the damping length. Numerically, we verify the previously obtained analytical expressions by means of the full solution of the resistive MHD eigenvalue problem beyond the TT and TB approximations. We find that the backward and forward propagating waves have different wavelengths and are damped on length scales that are inversely proportional to the frequency as in the static case. However, the factor of proportionality depends on the characteristics of the flow, so that the damping length differs from its static analog. For slow, sub-Alfvenic flows the backward propagating wave gets damped on a shorter length scale than in the absence of flow, while for the forward propagating wave the damping length is longer. The different properties of the waves depending on their direction of propagation with respect to the background flow may be detected by the observations and may be relevant for seismological applications.

  17. Saturated and Unsaturated Flow due to Tidal Fluctuation and Rainfall in a Coastal Aquifer

    NASA Astrophysics Data System (ADS)

    Yeh, Hund-Der; Chuang, Mo-Hsiung; Chang, Chia-Hao

    2016-04-01

    The prediction of groundwater level fluctuations due to tidal waves propagation and localized recharge in coastal aquifers is important for the development and management of water resources in coastal areas. Most of the past models for the recharge problem consider either saturated flow or unsaturated flow in the aquifers. However, it is expected that the recharge sources infiltrating from the ground surface have significant impact on the hydraulic heads in saturated and unsaturated zones of an unconfined aquifer in reality. The objective of this study is to derive a closed-form analytical expression for predicting tidal responses in a coastal aquifer system with considering rainfall recharge as well as coupled saturated and unsaturated flow. The model is composed of a linearized Richards equation for unsaturated flow coupled with the saturated groundwater flow equation. The top boundary at the ground surface is represented by the flux condition with a source term denoting the recharge in the coastal aquifer system. The solution of the model is developed in Cartesian coordinates based on the methods of Laplace transform and double-integral transform. On the basis of the analytical solution, the groundwater head fluctuations induced by the joint effect of rainfall and oceanic tides is examined in saturated and unsaturated zones of the aquifer. In addition, the influences of the unsaturated flow on the water table movement are also investigated and discussed. Key words: analytical solution, unsaturated flow, coastal aquifer.

  18. Blown Away: The Shedding and Oscillation of Sessile Drops by Cross Flowing Air

    NASA Astrophysics Data System (ADS)

    Milne, Andrew James Barnabas

    For drops sessile on a solid surface, cross flowing air can drive drop oscillation or shedding, based on the balance and interaction of aerodynamic drag force (based on drop size/shape and air speed) and adhesion/capillary forces (based on surface tension and drop size/shape). Better understanding of the above has applications to, e.g., fuel cell flooding, airfoil icing, and visibility in rain. To understand the basic physics, experiments studying individual sessile drops in a low speed wind tunnel were performed in this thesis. Analysis of high speed video gave time resolved profiles and airspeed for shedding. Testing 0.5 mul to 100 mul drops of water and hexadecane on poly(methyl methacrylate) PMMA, Teflon, and a superhydrophobic surface (SHS) yielded a master curve describing critical airspeed for shedding for water drops on all surface tested. This curve predicts behavior for new surfaces, and explains experimental results published previously. It also indicates that the higher contact angle leads to easier shedding due to decreased adhesion and increased drag. Developing a novel floating element differential drag sensor gave the first measurements of the microNewton drag force experienced by drops. Forces magnitude is comparable to gravitational shedding from a tilted plate and to simplified models for drop adhesion, with deviations that suggest effects due to the air flow. Fluid properties are seen to have little effect on drag versus airspeed, and decreased adhesion is seen to be more important than increased drag for easing shedding. The relation between drag coefficient and Reynolds number increases slightly with liquid-solid contact angle, and with drop volume. Results suggest that the drop experiences increased drag compared to similarly shaped solid bodies due to drop oscillations aeroelasticly coupling into the otherwise laminar flow. The bulk and surface oscillations of sessile drops in cross flow was also studied, using a full profile analysis

  19. Investigation of Countercurrent Helium-Air Flows in Air-ingress Accidents for VHTRs

    SciTech Connect

    Sun, Xiaodong; Christensen, Richard; Oh, Chang

    2013-10-03

    The primary objective of this research is to develop an extensive experimental database for the air- ingress phenomenon for the validation of computational fluid dynamics (CFD) analyses. This research is intended to be a separate-effects experimental study. However, the project team will perform a careful scaling analysis prior to designing a scaled-down test facility in order to closely tie this research with the real application. As a reference design in this study, the team will use the 600 MWth gas turbine modular helium reactor (GT-MHR) developed by General Atomic. In the test matrix of the experiments, researchers will vary the temperature and pressure of the helium— along with break size, location, shape, and orientation—to simulate deferent scenarios and to identify potential mitigation strategies. Under support of the Department of Energy, a high-temperature helium test facility has been designed and is currently being constructed at Ohio State University, primarily for high- temperature compact heat exchanger testing for the VHTR program. Once the facility is in operation (expected April 2009), this study will utilize high-temperature helium up to 900°C and 3 MPa for loss-of-coolant accident (LOCA) depressurization and air-ingress experiments. The project team will first conduct a scaling study and then design an air-ingress test facility. The major parameter to be measured in the experiments is oxygen (or nitrogen) concentration history at various locations following a LOCA scenario. The team will use two measurement techniques: 1) oxygen (or similar type) sensors employed in the flow field, which will introduce some undesirable intrusiveness, disturbing the flow, and 2) a planar laser-induced fluorescence (PLIF) imaging technique, which has no physical intrusiveness to the flow but requires a transparent window or test section that the laser beam can penetrate. The team will construct two test facilities, one for high-temperature helium tests with

  20. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

    SciTech Connect

    Battista, L.; Sciuto, S. A.; Scorza, A.

    2013-03-15

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 Multiplication-Sign 10{sup -4} m{sup 3}/s (18.0 l/min) for the mono-directional sensor and a measurement range of {+-}3.00 Multiplication-Sign 10{sup -4} m{sup 3}/s ({+-}18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed

  1. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

    NASA Astrophysics Data System (ADS)

    Battista, L.; Sciuto, S. A.; Scorza, A.

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10-4 m3/s (18.0 l/min) for the mono-directional sensor and a measurement range of ±3.00 × 10-4 m3/s (±18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the

  2. An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique.

    PubMed

    Battista, L; Sciuto, S A; Scorza, A

    2013-03-01

    In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10(-4) m(3)∕s (18.0 l∕min) for the mono-directional sensor and a measurement range of ±3.00 × 10(-4) m(3)∕s (±18.0 l∕min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono

  3. Use of exhaust gas as sweep flow to enhance air separation membrane performance

    DOEpatents

    Dutart, Charles H.; Choi, Cathy Y.

    2003-01-01

    An intake air separation system for an internal combustion engine is provided with purge gas or sweep flow on the permeate side of separation membranes in the air separation device. Exhaust gas from the engine is used as a purge gas flow, to increase oxygen flux in the separation device without increasing the nitrogen flux.

  4. 7 CFR 28.603 - Procedures for air flow tests of micronaire reading.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of the United States for Fiber Fineness and Maturity § 28.603 Procedures for air flow tests of micronaire reading. In determining in terms of micronaire readings, the fiber fineness and maturity, in...) Air flow instrument complete with accessories to measure the fineness and maturity, in combination, of...

  5. 7 CFR 28.603 - Procedures for air flow tests of micronaire reading.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of the United States for Fiber Fineness and Maturity § 28.603 Procedures for air flow tests of micronaire reading. In determining in terms of micronaire readings, the fiber fineness and maturity, in...) Air flow instrument complete with accessories to measure the fineness and maturity, in combination, of...

  6. 7 CFR 28.603 - Procedures for air flow tests of micronaire reading.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of the United States for Fiber Fineness and Maturity § 28.603 Procedures for air flow tests of micronaire reading. In determining in terms of micronaire readings, the fiber fineness and maturity, in...) Air flow instrument complete with accessories to measure the fineness and maturity, in combination, of...

  7. 7 CFR 28.603 - Procedures for air flow tests of micronaire reading.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of the United States for Fiber Fineness and Maturity § 28.603 Procedures for air flow tests of micronaire reading. In determining in terms of micronaire readings, the fiber fineness and maturity, in...) Air flow instrument complete with accessories to measure the fineness and maturity, in combination, of...

  8. MODELING AIR FLOW DYNAMICS IN RADON MITIGATION SYSTEMS: A SIMPLIFIED APPROACH

    EPA Science Inventory

    The paper refines and extends an earlier study--relating to the design of optimal radon mitigation systems based on subslab depressurization-- that suggested that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained betw...

  9. MODELING AIR FLOW DYNAMICS IN RADON MITIGATION SYSTEMS: A SIMPLIFIED APPROACH

    EPA Science Inventory

    The paper refines and extends an earlier study--relating to the design of optimal radon mitigation systems based on subslab depressurization-- that suggested that subslab air flow induced by a central suction point be treated as radial air flow through a porous bed contained betw...

  10. Deterministic Domain Wall Motion Orthogonal To Current Flow Due To Spin Orbit Torque

    PubMed Central

    Bhowmik, Debanjan; Nowakowski, Mark E.; You, Long; Lee, OukJae; Keating, David; Wong, Mark; Bokor, Jeffrey; Salahuddin, Sayeef

    2015-01-01

    Spin-polarized electrons can move a ferromagnetic domain wall through the transfer of spin angular momentum when current flows in a magnetic nanowire. Such current induced control of a domain wall is of significant interest due to its potential application for low power ultra high-density data storage. In previous reports, it has been observed that the motion of the domain wall always happens parallel to the current flow – either in the same or opposite direction depending on the specific nature of the interaction. In contrast, here we demonstrate deterministic control of a ferromagnetic domain wall orthogonal to current flow by exploiting the spin orbit torque in a perpendicularly polarized Ta/CoFeB/MgO heterostructure in presence of an in-plane magnetic field. Reversing the polarity of either the current flow or the in-plane field is found to reverse the direction of the domain wall motion. Notably, such orthogonal motion with respect to current flow is not possible from traditional spin transfer torque driven domain wall propagation even in presence of an external magnetic field. Therefore the domain wall motion happens purely due to spin orbit torque. These results represent a completely new degree of freedom in current induced control of a ferromagnetic domain wall. PMID:26139349

  11. Flow measurement in base cooling air passages of a rotating turbine blade

    NASA Technical Reports Server (NTRS)

    Liebert, C. H.; Pollack, F. G.

    1974-01-01

    The operational performance is decribed of a shaft-mounted system for measuring the air mass flow rate in the base cooling passages of a rotating turbine blade. Shaft speeds of 0 to 9000 rpm, air mass flow rates of 0.0035 to 0.039 kg/sec (0.0077 to 0.085 lbm/sec), and blade air temperatures of 300 to 385 K (80 to 233 F) were measured. Comparisons of individual rotating blade flows and corresponding stationary supply orifice flows agreed to within 10 percent.

  12. Linear permeability evolution of expanding conduits due to feedback between flow and fast phase change

    NASA Astrophysics Data System (ADS)

    Wang, Lichun; Cardenas, M. Bayani

    2017-05-01

    Conduits are ubiquitous and critical pathways for many fluids relevant for geophysical processes such as magma, water, and gases. Predicting flow through conduits is challenging when the conduit geometry coevolves with the flow. We theoretically show that the permeability (k) of a conduit whose walls are eroding due to fast phase change increases linearly with time because of a self-reinforcing mechanism. This simple result is surprising given complex feedbacks between flow, transport, and phase change. The theory is congruent with previous experimental observations of fracture dissolution in calcite. Supporting computational fracture dissolution experiments showed that k only slightly increases until the dissolution front reaches the narrowest conduit constriction, after which the linear evolution of k manifests. The theory holds across multiple scales and a broad range of Peclet and Damkohler numbers and thus advances the prediction of dynamic mass fluxes through expanding conduits in various geologic and environmental settings.Plain Language SummaryGeological conduits are ubiquitous present in the subsurface. In many situations, these conduits may enlarge through time <span class="hlt">due</span> to erosion of its walls by dissolution and melting. This leads to strongly coupled <span class="hlt">flow</span> and reactive transport processes where the <span class="hlt">flow</span> dictates the wall's erosion and vice versa. As the conduit expands, so does its permeability and thus <span class="hlt">flow</span>. Thus, predicting fluid <span class="hlt">flow</span> and relevant transport processes through expanding conduits is challenging. In this study, we presented a theory for the linear time dependence of permeability for expanding conduits. The theory is congruent with previous observations from fracture dissolution in calcite. An additional series of our own computational experiments also aligns with the theory. The theory will be of interest to geoscientists and engineers in many fields such as hydrology, glaciology, and petroleum</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21728014','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21728014"><span>Egomotion estimation with optic <span class="hlt">flow</span> and <span class="hlt">air</span> velocity sensors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rutkowski, Adam J; Miller, Mikel M; Quinn, Roger D; Willis, Mark A</p> <p>2011-06-01</p> <p>We develop a method that allows a flyer to estimate its own motion (egomotion), the wind velocity, ground slope, and flight height using only inputs from onboard optic <span class="hlt">flow</span> and <span class="hlt">air</span> velocity sensors. Our artificial algorithm demonstrates how it could be possible for flying insects to determine their absolute egomotion using their available sensors, namely their eyes and wind sensitive hairs and antennae. Although many behaviors can be performed by only knowing the direction of travel, behavioral experiments indicate that odor tracking insects are able to estimate the wind direction and control their absolute egomotion (i.e., groundspeed). The egomotion estimation method that we have developed, which we call the opto-aeronautic algorithm, is tested in a variety of wind and ground slope conditions using a video recorded flight of a moth tracking a pheromone plume. Over all test cases that we examined, the algorithm achieved a mean absolute error in height of 7% or less. Furthermore, our algorithm is suitable for the navigation of aerial vehicles in environments where signals from the Global Positioning System are unavailable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010APS..DFD.QX010H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010APS..DFD.QX010H"><span>Characterization of Turbulence and Cavitation Induced Pipe Vibrations <span class="hlt">Due</span> to <span class="hlt">Flow</span> thru Baffle Plates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holt, Gavin; Maynes, Daniel; Blotter, Jonathan</p> <p>2010-11-01</p> <p>We report experimental results characterizing pipe vibrations caused by turbulent <span class="hlt">flow</span> and cavitation <span class="hlt">due</span> to water <span class="hlt">flow</span> through baffle plates mounted in a 10.2 cm diameter schedule 40 PVC pipe test section of a closed water <span class="hlt">flow</span> loop. The baffle plates contained varying hole sizes that ranged from 0.159 cm to 2.54 cm, with the total through area, or openness, of each baffle plate ranging between 11% and 60%. Pipe wall acceleration data was collected for a range of Reynolds numbers from 5-85 x 10^4. Acceleration measurements were acquired at locations along the pipe from 3-110 diameters downstream of the baffle plate. The measurements show that vibration levels at a given streamwise position increase with larger holes size, a decrease in openness, and increased <span class="hlt">flow</span> rate. The incipient point of cavitation was observed to occur at decreasing <span class="hlt">flow</span> rate with increasing hole size and decreasing openness. Vibration levels decreased asymptotically with increased distance downstream of the baffle plate for all scenarios and the streamwise distance at which the vibration level was attenuated increased as the hole size increased, openness decreased, and <span class="hlt">flow</span> rate increased. The downstream vibration level also increased with these parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27966666','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27966666"><span>Measurement error in mobile source <span class="hlt">air</span> pollution exposure estimates <span class="hlt">due</span> to residential mobility during pregnancy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pennington, Audrey Flak; Strickland, Matthew J; Klein, Mitchel; Zhai, Xinxin; Russell, Armistead G; Hansen, Craig; Darrow, Lyndsey A</p> <p>2016-12-14</p> <p>Prenatal <span class="hlt">air</span> pollution exposure is frequently estimated using maternal residential location at the time of delivery as a proxy for residence during pregnancy. We describe residential mobility during pregnancy among 19,951 children from the Kaiser <span class="hlt">Air</span> Pollution and Pediatric Asthma Study, quantify measurement error in spatially resolved estimates of prenatal exposure to mobile source fine particulate matter (PM2.5) <span class="hlt">due</span> to ignoring this mobility, and simulate the impact of this error on estimates of epidemiologic associations. Two exposure estimates were compared, one calculated using complete residential histories during pregnancy (weighted average based on time spent at each address) and the second calculated using only residence at birth. Estimates were computed using annual averages of primary PM2.5 from traffic emissions modeled using a Research LINE-source dispersion model for near-surface releases (RLINE) at 250 m resolution. In this cohort, 18.6% of children were born to mothers who moved at least once during pregnancy. Mobile source PM2.5 exposure estimates calculated using complete residential histories during pregnancy and only residence at birth were highly correlated (rS>0.9). Simulations indicated that ignoring residential mobility resulted in modest bias of epidemiologic associations toward the null, but varied by maternal characteristics and prenatal exposure windows of interest (ranging from -2% to -10% bias).Journal of Exposure Science and Environmental Epidemiology advance online publication, 14 December 2016; doi:10.1038/jes.2016.66.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JTePh..55..270K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JTePh..55..270K"><span>Soft X-ray radiation <span class="hlt">due</span> to a nanosecond diffuse discharge in atmospheric-pressure <span class="hlt">air</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kostyrya, I. D.; Tarasenko, V. F.</p> <p>2010-02-01</p> <p>A source of soft X-rays with an effective photon energy of 9 keV and a subnanosecond pulse width is built around a gas diode filled with atmospheric-pressure <span class="hlt">air</span> and a UAEB-150 generator. A collector placed behind a grounded mesh electrode detects an electron beam and a pulse with positive polarity, the latter being <span class="hlt">due</span> to an electric field surrounding the mesh. It is shown that the intensity of soft X-rays from the gas-diode-based source depends on the material of a massive potential anode; namely, it grows with an increase in the atomic number of the cathode material. In the case of a tantalum anode, X-ray photons with an effective energy of 9 and 17 keV contribute to the exposure dose.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19044734','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19044734"><span>A transistor based <span class="hlt">air</span> <span class="hlt">flow</span> transducer for thermohygrometric control of neonatal ventilatory applications.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schena, Emiliano; Silvestri, Sergio</p> <p>2008-10-01</p> <p>An <span class="hlt">air</span> <span class="hlt">flow</span> transducer for controlling heated humidifiers used in neonatal artificial ventilation, suitable for in-line application in monopatient breathing circuits, is described here. The sensor is built with two nominally identical bipolar junction transistors, with different packages, as hot elements operated at a regulated constant voltage. The operation principle is based on the differential convective heat power exchanged with the fluid stream <span class="hlt">due</span> to the different thermal conductivities of the transistors' packages. The underlying theory is described in mathematical terms and the theoretical model is validated with experimental data in the mass <span class="hlt">flow</span> rate range from 4 to 215 mg s(-1). The nonlinear behavior allows sensitivities from -5 mV/(mg s(-1)) at <span class="hlt">flow</span> rates in the range of 4-130 mg s(-1) to -2 mV/(mg s(-1)) at higher <span class="hlt">flow</span> rates up to 215 mg s(-1). The linear range extends from 40 to 130 mg s(-1), with constant sensitivity equal to -5 mV/(mg s(-1)). The differential nature of the output allows to obtain repeatabilities in the order of 2% for fluid temperatures between 20 and 25 degrees C and of about 6% if the fluid temperature lies in the range of 15-35 degrees C. The relatively long time constant, in the order of 20+/-5 s, makes the sensor suitable for average <span class="hlt">flow</span> rate measurements. Using the sensor's output as a control variable of a heated humidifier for artificial ventilation, the relative humidity of gases varies by only 20% in the <span class="hlt">flow</span> rate range of the sensor (from 95% to 75%), whereas the same parameter shows a variation of about 40% (from 100% to 60%) with the same humidifier without <span class="hlt">flow</span> control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/800965','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/800965"><span>Numerical Predictions and Experimental Results of <span class="hlt">Air</span> <span class="hlt">Flow</span> in a Smooth Quarter-Scale Nacelle</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>BLACK, AMALIA R.; SUO-ANTTILA, JILL M.; GRITZO, LOUIS A.; DISIMILE, PETER J.; TUCKER, JAMES R.</p> <p>2002-06-01</p> <p>Fires in aircraft engine nacelles must be rapidly suppressed to avoid loss of life and property. The design of new and retrofit suppression systems has become significantly more challenging <span class="hlt">due</span> to the ban on production of Halon 1301 for environmental concerns. Since fire dynamics and the transport of suppressants within the nacelle are both largely determined by the available <span class="hlt">air</span> <span class="hlt">flow</span>, efforts to define systems using less effective suppressants greatly benefit from characterization of nacelle <span class="hlt">air</span> <span class="hlt">flow</span> fields. A combined experimental and computational study of nacelle <span class="hlt">air</span> <span class="hlt">flow</span> therefore has been initiated. Calculations have been performed using both CFD-ACE (a Computational Fluid Dynamics (CFD) model with a body-fitted coordinate grid) and WLCAN (a CFD-based fire field model with a Cartesian ''brick'' shaped grid). The <span class="hlt">flow</span> conditions examined in this study correspond to the same Reynolds number as test data from the full-scale nacelle simulator at the 46 Test Wing. Pre-test simulations of a quarter-scale test fixture were performed using CFD-ACE and WLCAN prior to fabrication. Based on these pre-test simulations, a quarter-scale test fixture was designed and fabricated for the purpose of obtaining spatially-resolved measurements of velocity and turbulence intensity in a smooth nacelle. Post-test calculations have been performed for the conditions of the experiment and compared with experimental results obtained from the quarter-scale test fixture. In addition, several different simulations were performed to assess the sensitivity of the predictions to the grid size, to the turbulence models, and to the use of wall functions. In general, the velocity predictions show very good agreement with the data in the center of the channel but deviate near the walls. The turbulence intensity results tend to amplify the differences in velocity, although most of the trends are in agreement. In addition, there were some differences between WLCAN and CFD-ACE results in the angled</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhDT.......301S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhDT.......301S"><span>Numerical simulation of cantilevered ramp injector <span class="hlt">flow</span> fields for hypervelocity fuel/<span class="hlt">air</span> mixing enhancement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schumacher, Jurgen Christian</p> <p></p> <p>Increasing demand for affordable access to space and high speed terrestrial transport has spawned research interest into various <span class="hlt">air</span>-breathing hypersonic propulsion systems. Propulsion concepts such as the supersonic combustion ramjet (scramjet) and the shock-induced combustion ramjet (shcramjet) utilize oxygen freely available in the atmosphere and thereby substantially reduce the weight penalty of on-board oxidizer tankage used in rocket based systems. Of key importance to the ultimate success of an <span class="hlt">air</span>-breathing concept is the ability to efficiently mix the fuel with atmospheric <span class="hlt">air</span>. In the case of a hypersonic <span class="hlt">air</span>-breather the challenge is accentuated <span class="hlt">due</span> to the requirement of supersonic combustion. <span class="hlt">Flow</span> velocities through the combustor on the order of thousands of meters per second provide the fuel and <span class="hlt">air</span> with only a brief time to adequately combine. Contemporary mixing augmentation methods to address this issue have focused on fuel injection devices which promote axial vortices to enhance the mixing process. Much research effort has been expended on investigation of ramp injectors for this purpose. The present study introduces a new ramp injector design, based on the conventional ramp injector, dubbed the cantilevered ramp injector. A two-pronged numerical approach was employed to investigate the mixing performance and characteristics of the cantilevered injector consisting of, (1) comparison with conventional designs and (2) a parametric study of various cantilevered injector geometries. A laminar, three-dimensional, multispecies flowsolver was developed in generalized coordinates to solve the Navier-Stokes equations for the <span class="hlt">flow</span> fields of injected H2 into high-enthalpy <span class="hlt">air</span>. The scheme consists of an upwind TVD scheme for discretization of the convective fluxes coupled with a semi-implicit LU-SGS scheme for temporal discretization. Through analysis of the numerical solutions, it has been shown that the cantilevered ramp injector is a viable fuel injection</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20113126','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20113126"><span>Recovery of rectified signals from hot-wire/film anemometers <span class="hlt">due</span> to <span class="hlt">flow</span> reversal in oscillating <span class="hlt">flows</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Yingchen; Jones, Douglas L; Liu, Chang</p> <p>2010-01-01</p> <p>Hot-wire/film anemometers have been broadly used in experimental studies in fluid mechanics, acoustics, and ocean engineering. Yet, it is well known that hot-wire/film anemometers rectify the signal outputs <span class="hlt">due</span> to the lack of sensitivity to <span class="hlt">flow</span> direction. This main drawback, in turn, makes them less useful for diverse fluctuating <span class="hlt">flow</span> measurements. To solve this issue, a rectification recovery method has been developed based on reconstruction of the Fourier series expansion in conjunction with signal-squaring approach. This signal recovery method was experimentally examined and proven to be successful for both conventional and microfabricated hot-wire/film anemometers. The method was further applied to dipole field measurements, with data from recovered signals perfectly matching the analytical model of the dipole field.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1036044','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1036044"><span>Managing the Drivers of <span class="hlt">Air</span> <span class="hlt">Flow</span> and Water Vapor Transport in Existing Single Family Homes (Revised)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cummings, J.; Withers, C.; Martin, E.; Moyer, N.</p> <p>2012-10-01</p> <p>This document focuses on managing the driving forces which move <span class="hlt">air</span> and moisture across the building envelope. While other previously published Measure Guidelines focus on elimination of <span class="hlt">air</span> pathways, the ultimate goal of this Measure Guideline is to manage drivers which cause <span class="hlt">air</span> <span class="hlt">flow</span> and water vapor transport across the building envelope (and also within the home), control <span class="hlt">air</span> infiltration, keep relative humidity (RH) within acceptable limits, avoid combustion safety problems, improve occupant comfort, and reduce house energy use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70029430','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70029430"><span>Sheet <span class="hlt">flow</span> and suspended sediment <span class="hlt">due</span> to wave groups in a large wave flume</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dohmen-Janssen, C. M.; Hanes, D.M.</p> <p>2005-01-01</p> <p>A series of sand bed experiments was carried out in the Large Wave Flume in Hannover, Germany as a component of the SISTEX99 experiment. The experiments focussed on the dynamic sediment response <span class="hlt">due</span> to wave group forcing over a flat sand bed in order to improve understanding of cross-shore sediment transport mechanisms and determine sediment concentrations, fluxes and net transport rates under these conditions. Sediment concentrations were measured within the sheet <span class="hlt">flow</span> layer (thickness in the order of 10 grain diameters) and in the suspension region (thickness in the order of centimetres). Within the sheet <span class="hlt">flow</span> layer, the concentrations are highly coherent with the instantaneous near-bed velocities <span class="hlt">due</span> to each wave within the wave group. However, in the suspension layer concentrations respond much more slowly to changes in near-bed velocity. At several centimetres above the bed, the suspended sediment concentrations vary on the time scale of the wave group, with a time delay relative to the peak wave within the wave group. The thickness of the sheet <span class="hlt">flow</span> changes with time. It is strongly coherent with the wave forcing, and is not influenced by the history or sequence of the waves within the group. The velocity of the sediment was also measured within the sheet <span class="hlt">flow</span> layer some of the time (during the larger wave crests of the group), and the velocity of the fluid was measured at several cm above the sheet <span class="hlt">flow</span> layer. The grain velocity and concentration estimates can be combined to estimate the sediment flux. The estimates were found to be consistent with previous measurements under monochromatic waves. Under these conditions, without any significant mean current, the sediment flux within the sheet <span class="hlt">flow</span> layer was found to greatly exceed the sediment flux in the suspension layer. As a result, net transport rates under wave groups are similar to those under monochromatic waves. ?? 2004 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27433526','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27433526"><span>Approximate Solutions for <span class="hlt">Flow</span> with a Stretching Boundary <span class="hlt">due</span> to Partial Slip.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Filobello-Nino, U; Vazquez-Leal, H; Sarmiento-Reyes, A; Benhammouda, B; Jimenez-Fernandez, V M; Pereyra-Diaz, D; Perez-Sesma, A; Cervantes-Perez, J; Huerta-Chua, J; Sanchez-Orea, J; Contreras-Hernandez, A D</p> <p>2014-01-01</p> <p>The homotopy perturbation method (HPM) is coupled with versions of Laplace-Padé and Padé methods to provide an approximate solution to the nonlinear differential equation that describes the behaviour of a <span class="hlt">flow</span> with a stretching flat boundary <span class="hlt">due</span> to partial slip. Comparing results between approximate and numerical solutions, we concluded that our results are capable of providing an accurate solution and are extremely efficient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4897153','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4897153"><span>Approximate Solutions for <span class="hlt">Flow</span> with a Stretching Boundary <span class="hlt">due</span> to Partial Slip</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Filobello-Nino, U.; Vazquez-Leal, H.; Sarmiento-Reyes, A.; Benhammouda, B.; Jimenez-Fernandez, V. M.; Pereyra-Diaz, D.; Perez-Sesma, A.; Cervantes-Perez, J.; Huerta-Chua, J.; Sanchez-Orea, J.; Contreras-Hernandez, A. D.</p> <p>2014-01-01</p> <p>The homotopy perturbation method (HPM) is coupled with versions of Laplace-Padé and Padé methods to provide an approximate solution to the nonlinear differential equation that describes the behaviour of a <span class="hlt">flow</span> with a stretching flat boundary <span class="hlt">due</span> to partial slip. Comparing results between approximate and numerical solutions, we concluded that our results are capable of providing an accurate solution and are extremely efficient. PMID:27433526</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22271101','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22271101"><span>Two-phase <span class="hlt">air</span>-water stratified <span class="hlt">flow</span> measurement using ultrasonic techniques</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fan, Shiwei; Yan, Tinghu; Yeung, Hoi</p> <p>2014-04-11</p> <p>In this paper, a time resolved ultrasound system was developed for investigating two-phase <span class="hlt">air</span>-water stratified <span class="hlt">flow</span>. The hardware of the system includes a pulsed wave transducer, a pulser/receiver, and a digital oscilloscope. The time domain cross correlation method is used to calculate the velocity profile along ultrasonic beam. The system is able to provide velocities with spatial resolution of around 1mm and the temporal resolution of 200μs. Experiments were carried out on single phase water <span class="hlt">flow</span> and two-phase <span class="hlt">air</span>-water stratified <span class="hlt">flow</span>. For single phase water <span class="hlt">flow</span>, the <span class="hlt">flow</span> rates from ultrasound system were compared with those from electromagnetic <span class="hlt">flow</span> (EM) meter, which showed good agreement. Then, the experiments were conducted on two-phase <span class="hlt">air</span>-water stratified <span class="hlt">flow</span> and the results were given. Compared with liquid height measurement from conductance probe, it indicated that the measured velocities were explainable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740045297&hterms=Properties+Helium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DProperties%2BHelium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740045297&hterms=Properties+Helium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DProperties%2BHelium"><span><span class="hlt">Flow</span> properties in expansion tube with helium, argon, <span class="hlt">air</span>, and CO2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, C. G.</p> <p>1974-01-01</p> <p>Test <span class="hlt">flow</span> velocities from 5 to 7 km/sec were generated in a 6-in. expansion tube using helium, argon, <span class="hlt">air</span>, and CO2 test gases. Pitot pressure profiles across the <span class="hlt">flow</span> at the test section are presented for the four test gases, and measured <span class="hlt">flow</span> quantities are compared to computer predicted values. Comparison of predicted and measured <span class="hlt">flow</span> quantities suggests the expansion to be near thermochemical equilibrium for all test gases and implies the existence of a totally reflected shock at the secondary diaphragm. Argon, <span class="hlt">air</span>, and CO2 <span class="hlt">flows</span> were observed to attenuate while traversing the acceleration section, whereas no attenuation was observed for helium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MS%26E...52b2040C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MS%26E...52b2040C"><span><span class="hlt">Air</span>-structure coupling features analysis of mining contra-rotating axial <span class="hlt">flow</span> fan cascade</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Q. G.; Sun, W.; Li, F.; Zhang, Y. J.</p> <p>2013-12-01</p> <p>The interaction between contra-rotating axial <span class="hlt">flow</span> fan blade and working gas has been studied by means of establishing <span class="hlt">air</span>-structure coupling control equation and combining Computational Fluid Dynamics (CFD) and Computational solid mechanics (CSM). Based on the single <span class="hlt">flow</span> channel model, the Finite Volume Method was used to make the field discrete. Additionally, the SIMPLE algorithm, the Standard k-ε model and the Arbitrary Lagrangian-Eulerian dynamic grids technology were utilized to get the airflow motion by solving the discrete governing equations. At the same time, the Finite Element Method was used to make the field discrete to solve dynamic response characteristics of blade. Based on weak coupling method, data exchange from the fluid solver and the solid solver was processed on the coupling interface. Then interpolation was used to obtain the coupling characteristics. The results showed that the blade's maximum amplitude was on the tip of the last-stage blade and aerodynamic force signal could reflect the blade working conditions to some extent. By analyzing the <span class="hlt">flow</span> regime in contra-rotating axial <span class="hlt">flow</span> fan, it could be found that the vortex core region was mainly in the blade surface, the hub and the blade clearance. In those regions, the turbulence intensity was very high. The last-stage blade's operating life is shorter than that of the pre-stage blade <span class="hlt">due</span> to the fatigue fracture occurs much more easily on the last-stage blade which bears more stress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JThSc..26..308H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JThSc..26..308H"><span><span class="hlt">Flow</span> development through HP & LP turbines, Part II: Effects of the hub endwall secondary sealing <span class="hlt">air</span> <span class="hlt">flow</span> on the turbine's mainstream <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Jialin; Du, Qiang; Liu, Jun; Wang, Pei; Liu, Guang; Liu, Hongrui; Du, Meimei</p> <p>2017-08-01</p> <p>Although many literatures have been focused on the underneath <span class="hlt">flow</span> and loss mechanism, very few experiments and simulations have been done under the engines' representative working conditions or considering the real cavity structure as a whole. This paper aims at realizing the goal of design of efficient turbine and scrutinizing the velocity distribution in the vicinity of the rim seal. With the aid of numerical method, a numerical model describing the <span class="hlt">flow</span> pattern both in the purge <span class="hlt">flow</span> spot and within the mainstream <span class="hlt">flow</span> path is established, fluid migration and its accompanied <span class="hlt">flow</span> mechanism within the realistic cavity structure (with rim seal structure and considering mainstream & secondary <span class="hlt">air</span> <span class="hlt">flow</span>'s interaction) is used to evaluate both the <span class="hlt">flow</span> pattern and the underneath <span class="hlt">flow</span> mechanism within the inward rotating cavity. Meanwhile, the underneath <span class="hlt">flow</span> and loss mechanism are also studied in the current paper. The computational results show that the sealing <span class="hlt">air</span> <span class="hlt">flow</span>'s ingestion and ejection are highly interwound with each other in both upstream and downstream <span class="hlt">flow</span> of the rim seal. Both the down-stream blades' potential effects as well as the upstream blades' wake trajectory can bring about the ingestion of the hot gas <span class="hlt">flow</span> within the cavity, abrupt increase of the static pressure is believed to be the main reason. Also, the results indicate that sealing <span class="hlt">air</span> <span class="hlt">flow</span> ejected through the rear cavity will cause unexpected loss near the outlet section of the blades in the downstream of the HP rotor passages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8253132','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8253132"><span>[Invention of an <span class="hlt">air</span> forced ventilated micro-isolation cage and rack system--environment within the cages: ventilation, <span class="hlt">air</span> <span class="hlt">flow</span>].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kurosawa, T; Yoshida, K; Okamoto, M; Tajima, M</p> <p>1993-10-01</p> <p>A forced <span class="hlt">air</span> ventilation system for small laboratory animals was developed. The system consists of an <span class="hlt">air</span> handling unit with <span class="hlt">air</span> supply and exhaust fans, a rack, hard cage covers with a large diameter <span class="hlt">air</span> inlet and an outlet, and shoe box cages. <span class="hlt">Air</span> <span class="hlt">flow</span> from the supply duct, to the exhaust duct and within the cage were observed. Variations in <span class="hlt">air</span> <span class="hlt">flow</span> among cages was minimal. The optimal <span class="hlt">air</span> exchange rate of the cages in this system was determined to be 60 times per hour based on the results obtained in the present study. At this <span class="hlt">air</span> exchange rate, <span class="hlt">air</span> <span class="hlt">flow</span> at the base of the cages had a velocity of less than 0.09m/sec, which was within the range of recommended values for humans. The observed results show that the system developed is capable of sustaining a laboratory animal microenvironment well in terms of <span class="hlt">air</span> <span class="hlt">flow</span>, without too much energy cost.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15318774','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15318774"><span>Surface <span class="hlt">flow</span> boundary conditions in modeling land subsidence <span class="hlt">due</span> to fluid withdrawal.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Baú, Domenico; Ferronato, Massimiliano; Gambolati, Giuseppe; Teatini, Pietro</p> <p>2004-01-01</p> <p>Land subsidence <span class="hlt">due</span> to subsurface fluid (water, gas, oil) withdrawal is often predicted by either finite element or finite difference numerical models based on coupled poroelastic theory, where the soil is represented as a semi-infinite medium bounded by the traction-free (ground) surface. One of the variables playing a most important role on the final outcome is the <span class="hlt">flow</span> condition used on the traction-free boundary, which may be assumed as either permeable or impermeable. Although occasionally justified, the assumption of no-<span class="hlt">flow</span> surface seems to be in general rather unrealistic. A permeable boundary where the fluid pressure is fixed to the external atmospheric pressure appears to be more appropriate. This paper addresses the response, in terms of land subsidence, obtained with a coupled poroelastic finite element model that simulates a distributed pumping from a horizontal aquifer confined between two relatively impervious layers, and takes either a permeable boundary surface, i.e., constant hydraulic potential, or an impermeable boundary, i.e., a zero Neumann <span class="hlt">flow</span> condition. The analysis reveals that land subsidence is rather sensitive to the <span class="hlt">flow</span> condition implemented on the traction-free boundary. In general, the no-<span class="hlt">flow</span> condition leads to an overestimate of the predicted ground surface settlement, which could even be 1 order of magnitude larger than that obtained with the permeable boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20031149','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20031149"><span>Avalanches of coalescence events and local extensional <span class="hlt">flows</span>--stabilisation or destabilisation <span class="hlt">due</span> to surfactant.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gunes, Deniz Z; Clain, Xavier; Breton, Olivier; Mayor, Guy; Burbidge, Adam S</p> <p>2010-03-01</p> <p>From two-drop collision experiments, it is known that local extensional <span class="hlt">flow</span> favors coalescence. Recently, Bremond et al. used microfluidic methods to evidence this point. Similarly, we used specific microfluidic geometries to impose sudden extensional <span class="hlt">flow</span>, following drop collision under controlled conditions, and coalescence events were recorded with a high-speed camera. In this study we focus on the effect of surfactant on the coalescence, or stabilisation against it, between drops <span class="hlt">flowing</span> apart <span class="hlt">due</span> to either imposed external <span class="hlt">flow</span> or capillary forces related to drop shape relaxation. Coalescence can be induced even when drops are initially separated by an intersticial lubricating film by far thicker than the critical thickness for rupturing under the action of Van der Waals forces. This is particularly relevant to avalanches of coalescence events, in <span class="hlt">flowing</span> or even quiescent emulsions or foams. When non-ionic surfactant was used, it was observed that small concentrations apparently enhance coalescence in extension. But at higher concentrations it provides stabilisation through a specific mechanism of thread formation and rupture; the stabilisation mechanism can be complex.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H41D0853H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H41D0853H"><span>Predictions of <span class="hlt">Flow</span> Duration Curve Shifts <span class="hlt">Due</span> to Anthropogenic and Climatic Changes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henry, N. F.; Kroll, C. N.; Endreny, T. A.</p> <p>2014-12-01</p> <p>Methods are needed to understand and predict streamflows in systems undergoing anthropogenic and climatic alteration. This study is motivated by a need to develop methods to accurately estimate historical and future <span class="hlt">flow</span> regimes of the Delaware River to inform management decisions for the endangered dwarf wedgemussel (Alasmidonta heterodon). Many streamflow regimes in this system have undergone substantial alteration within the past 100 years. Here, <span class="hlt">flow</span> duration curves (FDCs), a common hydrologic tool used to assess <span class="hlt">flow</span> regimes, are created and examined at 145 Delaware River Basin catchments. These catchments have experienced various hydrologic alterations, including land use changes, water withdrawals, and river regulation <span class="hlt">due</span> to dams and reservoirs. Linear regression models are developed for various percentile <span class="hlt">flows</span> across a FDC. These models use watershed characteristics that describe observed <span class="hlt">flow</span> regimes in altered as well as unaltered systems. The characteristics that have the most significant influence on the shape of the FDCs are then identified and isolated as descriptors of the alteration. Once these models are developed to include these key variables, given a specific alteration (e.g. fresh water withdrawals, change in annual precipitation, etc.), a new <span class="hlt">flow</span> regime can be estimated. Preliminary results indicate that certain watershed characteristics related to alteration (e.g. magnitude of land fragmentation, water withdrawals, hydrologic disturbance index) are significant in our models and influence FDC patterns. The results of this study may prove to have broader applications in regards to water resources management as the methods developed here may serve as a predictive tool as human interference and climatic changes continue to alter <span class="hlt">flow</span> regimes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/472140','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/472140"><span>Permeability decline <span class="hlt">due</span> to <span class="hlt">flow</span> of dilute suspensions through porous media</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nasr-El-Din, H.A.</p> <p>1996-12-31</p> <p>Suspension <span class="hlt">flow</span> in porous media is encountered in many industrial applications. In the oil industry, suspended solids present in injected waters cart cause significant damage around the wellbore or deep in the formation. Depending on tire physical properties of tire solid particles, the porous medium, and operating conditions, solids can form external or internal filter cake, or just <span class="hlt">flow</span> through the media without causing any damage. External filter cake formation causes a fast and sharp drop in permeability or injectivity of the formation. Reversing the <span class="hlt">flow</span> direction can recover some of the damaged permeability. Internal filter cake formation cases a gradual or steady drop in permeability. Reversing the <span class="hlt">flow</span> direction will not recover tire damaged permeability. Increasing solids concentration or particle size will cause more damage to formation. Injection of low-salinity water into sandstone reservoirs can trigger fines migration and clay swelling. Both factors can damage the formation. Injection of water that is incompatible with the formation brine may cause precipitation of insoluble sulfates that cart plug the formation. Stimulation (or acidizing) the formation cart also produce solid particles that can damage the formation. Corrosion by-products (e.g., iron sulfide) cart block the <span class="hlt">flow</span> paths and reduce the permeability of the formation. Many experimental and modeling studies to predict formation damage <span class="hlt">due</span> to <span class="hlt">flow</span> of suspensions in porous media are discussed in this chapter. Solids can be present in injected waters or be generated in the formation. More research is needed to predict <span class="hlt">flow</span> of suspensions in porous media when solid particles invade and are generated in tire formation simultaneously. 71 refs., 19 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvE..91d3001V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvE..91d3001V"><span>Stability of the <span class="hlt">flow</span> in a soft tube deformed <span class="hlt">due</span> to an applied pressure gradient</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verma, M. K. S.; Kumaran, V.</p> <p>2015-04-01</p> <p>A linear stability analysis is carried out for the <span class="hlt">flow</span> through a tube with a soft wall in order to resolve the discrepancy of a factor of 10 for the transition Reynolds number between theoretical predictions in a cylindrical tube and the experiments of Verma and Kumaran [J. Fluid Mech. 705, 322 (2012), 10.1017/jfm.2011.55]. Here the effect of tube deformation (<span class="hlt">due</span> to the applied pressure difference) on the mean velocity profile and pressure gradient is incorporated in the stability analysis. The tube geometry and dimensions are reconstructed from experimental images, where it is found that there is an expansion and then a contraction of the tube in the streamwise direction. The mean velocity profiles at different downstream locations and the pressure gradient, determined using computational fluid dynamics, are found to be substantially modified by the tube deformation. The velocity profiles are then used in a linear stability analysis, where the growth rates of perturbations are calculated for the <span class="hlt">flow</span> through a tube with the wall modeled as a neo-Hookean elastic solid. The linear stability analysis is carried out for the mean velocity profiles at different downstream locations using the parallel <span class="hlt">flow</span> approximation. The analysis indicates that the <span class="hlt">flow</span> first becomes unstable in the downstream converging section of the tube where the <span class="hlt">flow</span> profile is more pluglike when compared to the parabolic <span class="hlt">flow</span> in a cylindrical tube. The <span class="hlt">flow</span> is stable in the upstream diverging section where the deformation is maximum. The prediction for the transition Reynolds number is in good agreement with experiments, indicating that the downstream tube convergence and the consequent modification in the mean velocity profile and pressure gradient could reduce the transition Reynolds number by an order of magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1220524','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1220524"><span>Laboratory Evaluation of <span class="hlt">Air</span> <span class="hlt">Flow</span> Measurement Methods for Residential HVAC Returns for New Instrument Standards</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Walker, Iain; Stratton, Chris</p> <p>2015-08-01</p> <p>This project improved the accuracy of <span class="hlt">air</span> <span class="hlt">flow</span> measurements used in commissioning California heating and <span class="hlt">air</span> conditioning systems in Title 24 (Building and Appliance Efficiency Standards), thereby improving system performance and efficiency of California residences. The research team at Lawrence Berkeley National Laboratory addressed the issue that typical tools used by contractors in the field to test <span class="hlt">air</span> <span class="hlt">flows</span> may not be accurate enough to measure return <span class="hlt">flows</span> used in Title 24 applications. The team developed guidance on performance of current diagnostics as well as a draft test method for use in future evaluations. The study team prepared a draft test method through ASTM International to determine the uncertainty of <span class="hlt">air</span> <span class="hlt">flow</span> measurements at residential heating ventilation and <span class="hlt">air</span> conditioning returns and other terminals. This test method, when finalized, can be used by the Energy Commission and other entities to specify required accuracy of measurement devices used to show compliance with standards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EPJWC..2501014F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EPJWC..2501014F"><span>An experimental setup for the study of the steady <span class="hlt">air</span> <span class="hlt">flow</span> in a diesel engine chamber</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández, Joaquín; José Vega, Emilio; Castilla, Alejandro; Marcos, Alberto; María Montanero, José; Barrio, Raúl</p> <p>2012-04-01</p> <p>We present an experimental setup for studying the steady <span class="hlt">air</span> <span class="hlt">flow</span> in a diesel engine chamber. An engine block containing the inlet manifold was placed on a test bench. A steady <span class="hlt">air</span> stream crossed the inlet manifold and entered a glass chamber driven by a fan. A PIV system was set up around the bench to measure the in-chamber <span class="hlt">flow</span>. An <span class="hlt">air</span> spray gun was used as seed generator to producing sub-millimeter droplets, easily dragged by the <span class="hlt">air</span> stream. Images of the in-<span class="hlt">flow</span> chamber were acquired in the course of the experiments, and processed to measure the velocity field. The pressure drop driven the <span class="hlt">air</span> current and the mass <span class="hlt">flow</span> rate were also measured.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.745c2049J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.745c2049J"><span>Experimental analysis of the velocity field of the <span class="hlt">air</span> <span class="hlt">flowing</span> through the swirl diffusers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaszczur, M.; Branny, M.; Karch, M.; Borowski, M.</p> <p>2016-09-01</p> <p>The article presents the results of experimental studies of <span class="hlt">flow</span> of <span class="hlt">air</span> through diffusers. Presented laboratory model is a simplification of the real system and was made in a geometric scale 1:10. Simplifying refer both to the geometry of the object and conditions of <span class="hlt">air</span> <span class="hlt">flow</span>. The aim of the study is to determine the actual velocity fields of <span class="hlt">air</span> <span class="hlt">flowing</span> out of the swirl diffuser. The results obtained for the diffuser various settings are presented. We have tested various <span class="hlt">flow</span> rates of <span class="hlt">air</span>. Stereo Particle Image Velocimetry (SPIV) method was used to measure all velocity vector components. The experimental results allow to determine the actual penetration depth of the supply <span class="hlt">air</span> into the room. This will allow for better definition of the conditions of ventilation in buildings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26918522','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26918522"><span>Plant pneumatics: stem <span class="hlt">air</span> <span class="hlt">flow</span> is related to embolism - new perspectives on methods in plant hydraulics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pereira, Luciano; Bittencourt, Paulo R L; Oliveira, Rafael S; Junior, Mauro B M; Barros, Fernanda V; Ribeiro, Rafael V; Mazzafera, Paulo</p> <p>2016-07-01</p> <p>Wood contains a large amount of <span class="hlt">air</span>, even in functional xylem. <span class="hlt">Air</span> embolisms in the xylem affect water transport and can determine plant growth and survival. Embolisms are usually estimated with laborious hydraulic methods, which can be prone to several artefacts. Here, we describe a new method for estimating embolisms that is based on <span class="hlt">air</span> <span class="hlt">flow</span> measurements of entire branches. To calculate the amount of <span class="hlt">air</span> <span class="hlt">flowing</span> out of the branch, a vacuum was applied to the cut bases of branches under different water potentials. We first investigated the source of <span class="hlt">air</span> by determining whether it came from inside or outside the branch. Second, we compared embolism curves according to <span class="hlt">air</span> <span class="hlt">flow</span> or hydraulic measurements in 15 vessel- and tracheid-bearing species to test the hypothesis that the <span class="hlt">air</span> <span class="hlt">flow</span> is related to embolism. <span class="hlt">Air</span> <span class="hlt">flow</span> came almost exclusively from <span class="hlt">air</span> inside the branch during the 2.5-min measurements and was strongly related to embolism. We propose a new embolism measurement method that is simple, effective, rapid and inexpensive, and that allows several measurements on the same branch, thus opening up new possibilities for studying plant hydraulics. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/7368492','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/7368492"><span>Indoor <span class="hlt">air</span> <span class="hlt">flow</span> and pollutant removal in a room with desk-top ventilation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faulkner, D.; Fisk, W.J.; Sullivan, D.P.</p> <p>1993-04-01</p> <p>In a furnished experimental facility with three workstations separated by partitions, we studied indoor <span class="hlt">air</span> <span class="hlt">flow</span> patterns and tobacco smoke removal efficiency of a desk-top task ventilation system. The task ventilation system permits occupant control of the temperature, <span class="hlt">flow</span> rate and direction of <span class="hlt">air</span> supplied through two desk-mounted supply nozzles. In the configuration evaluated, <span class="hlt">air</span> exited the ventilated space through a ceiling-mounted return grill. To study indoor <span class="hlt">air</span> <span class="hlt">flow</span> patterns, we measured the age of <span class="hlt">air</span> at multiple indoor locations using the tracer gas step-up procedure. To study the intra-room transport of tobacco smoke particles and the efficiency of panicle removal by ventilation, a cigarette was smoked mechanically in one workstation and particle concentrations were measured at multiple indoor locations including the exhaust airstream. Test variables included the direction of <span class="hlt">air</span> supply from the nozzles, supply nozzle area, supply <span class="hlt">flow</span> rate and temperature, percent recirculation of chamber <span class="hlt">air</span>, and internal heatloads. With nozzles pointed toward the occupants, 100% outside <span class="hlt">air</span> supplied at the desk-top, and <span class="hlt">air</span> supply rates of approximately 40 L/s per workstation, the age of <span class="hlt">air</span> at the breathing level of ventilated workstations was approximately 30% less than the age of <span class="hlt">air</span> that would occur throughout the test space with perfectly mixed indoor <span class="hlt">air</span>. With smaller <span class="hlt">air</span> supply rates and/or <span class="hlt">air</span> supplied parallel to the edges of the desk, ages of <span class="hlt">air</span> at breathing locations were not significantly lower than the age with perfect mixing. Indoor tobacco smoke particle concentrations at specific locations were generally within 12% of the average measured indoor concentration and concentrations of particles in the exhaust airstream were not significantly different from concentration of particles at breathing locations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770023145','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770023145"><span>Cold <span class="hlt">air</span> performance of a 12.766-centimeter-tip-diameter axial-<span class="hlt">flow</span> cooled turbine. 2: Effect of <span class="hlt">air</span> ejection on turbine performance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Haas, J. E.; Kofskey, M. G.</p> <p>1977-01-01</p> <p>An <span class="hlt">air</span> cooled version of a single-stage, axial-<span class="hlt">flow</span> turbine was investigated to determine aerodynamic performance with and without <span class="hlt">air</span> ejection from the stator and rotor blades surfaces to simulate the effect of cooling <span class="hlt">air</span> discharge. <span class="hlt">Air</span> ejection rate was varied from 0 to 10 percent of turbine mass <span class="hlt">flow</span> for both the stator and the rotor. A primary-to-<span class="hlt">air</span> ejection temperature ratio of about 1 was maintained.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26ES...81a2118C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26ES...81a2118C"><span>The research of press drop of compressed <span class="hlt">air</span> foam <span class="hlt">flow</span> through the bend</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Y.; Chen, T.; Hu, C.; Fu, X. C.; Bao, Z. M.; Zhang, X. Z.; Xia, J. J.</p> <p>2017-08-01</p> <p>Compressed <span class="hlt">air</span> foam system (CAFS) had obvious advantages in engineering. The <span class="hlt">flow</span> model of compressed <span class="hlt">air</span> foam in the pipeline was different from water <span class="hlt">flow</span> model because the foam was the gas-liquid two phase <span class="hlt">flow</span> with non-Newtonian fluid properties and compressibility, and, the water supply theory was not suitable for foam press pipeline transport. At present, there was little research on non-Newtonian fluid <span class="hlt">flow</span>, especially the foam <span class="hlt">flow</span>. This study researched the effect of foam flux, end valve and foam type on the press in the straight pipe and bend. The press drop in straight pipes and bends filled with compressed <span class="hlt">air</span> foam was analyzed, and the result could provide experimental support for theoretical calculation of compressed <span class="hlt">air</span> foam in bend.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770022228','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770022228"><span>Experimental and analytical dynamic <span class="hlt">flow</span> characteristics of an axial-<span class="hlt">flow</span> fan from an <span class="hlt">air</span> cushion landing system model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thompson, W. C.; Boghani, A. B.; Leland, T. J. W.</p> <p>1977-01-01</p> <p>An investigation was conducted to compare the steady-state and dynamic <span class="hlt">flow</span> characteristics of an axial-<span class="hlt">flow</span> fan which had been used previously as the <span class="hlt">air</span> supply fan for some model <span class="hlt">air</span> cushion landing system studies. Steady-state <span class="hlt">flow</span> characteristics were determined in the standard manner by using differential orifice pressures for the <span class="hlt">flow</span> regime from free <span class="hlt">flow</span> to zero <span class="hlt">flow</span>. In this same regime, a correlative technique was established so that fan inlet and outlet pressures could be used to measure dynamic <span class="hlt">flow</span> as created by a rotating damper. Dynamic tests at damper frequencies up to 5 Hz showed very different <span class="hlt">flow</span> characteristics when compared with steady-state <span class="hlt">flow</span>, particularly with respect to peak pressures and the pressure-<span class="hlt">flow</span> relationship at fan stall and unstall. A generalized, rational mathematical fan model was developed based on physical fan parameters and a steady-state <span class="hlt">flow</span> characteristic. The model showed good correlation with experimental tests at damper frequencies up to 5 Hz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1071988','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1071988"><span>Modeling the <span class="hlt">Air</span> <span class="hlt">Flow</span> in the 3410 Building Filtered Exhaust Stack System</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Recknagle, Kurtis P.; Barnett, J. Matthew; Suffield, Sarah R.</p> <p>2013-01-23</p> <p>Additional ventilation capacity has been designed for the 3410 Building filtered exhaust stack system. The updated system will increase the number of fans from two to three and will include ductwork to incorporate the new fan into the existing stack. Stack operations will involve running various two-fan combinations at any given time. The <span class="hlt">air</span> monitoring system of the existing two-fan stack was previously found to be in compliance with the ANSI/HPS N13.1-1999 standard, however it is not known if the modified (three-fan) system will comply. Subsequently, a full-scale three-dimensional (3-D) computational fluid dynamics (CFD) model of the modified stack system has been created to examine the sampling location for compliance with the standard. The CFD modeling results show good agreement with testing data collected from the existing 3410 Building stack and suggest that velocity uniformity and <span class="hlt">flow</span> angles will remain well within acceptance criteria when the third fan and associated ductwork is installed. This includes two-fan <span class="hlt">flow</span> rates up to 31,840 cfm for any of the two-fan combinations. For simulation cases in which tracer gas and particles are introduced in the main duct, the model predicts that both particle and tracer gas coefficients of variance (COVs) may be larger than the acceptable 20 percent criterion of the ANSI/HPS N13.1-1999 standard for each of the two-fan, 31,840 cfm combinations. Simulations in which the tracers are introduced near the fans result in improved, though marginally acceptable, COV values for the tracers. <span class="hlt">Due</span> to the remaining uncertainty that the stack will qualify with the addition of the third fan and high <span class="hlt">flow</span> rates, a stationary <span class="hlt">air</span> blender from Blender Products, Inc. is considered for inclusion in the stack system. A model of the <span class="hlt">air</span> blender has been developed and incorporated into the CFD model. Simulation results from the CFD model that includes the <span class="hlt">air</span> blender show striking improvements in tracer gas mixing and tracer particle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23370575','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23370575"><span>Fatal postpartum <span class="hlt">air</span> embolism <span class="hlt">due</span> to uterine inversion and atonic hemorrhage.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Banaschak, Sibylle; Janßen, Katharina; Becker, Katrin; Friedrich, Krischan; Rothschild, Markus A</p> <p>2014-01-01</p> <p>We report a case of a 19-year-old woman who developed a persistent uterine hemorrhage after spontaneous delivery of a healthy child. Emergency laparotomy was indicated and then begun under stable circulatory conditions. Cardiac arrest occurred during the course of massive manual compression and packing of the uterus. After successful resuscitation, a supracervical hysterectomy was performed. During the suturing of the remaining cervix, a second cardiac arrest followed. The procedure was completed under constant external heart massage. Resuscitation was terminated <span class="hlt">due</span> to the persistence of widened pupils. An autopsy was ordered by the public prosecutor as the manner of death was declared to be unascertained. An X-ray and a CT scan prior to the autopsy showed extensive gas embolism in both arterial and venous vessels extending from the pelvic region to the head. During the autopsy, gas was collected by aspirometer from the right ventricle of the heart. The autopsy showed no additional relevant findings, and gas analysis confirmed the suspicion of <span class="hlt">air</span> embolism. The histological examination of the excised uterus especially in the corpus/fundus revealed an edema of the local smooth muscle cells and dilated vessels showing no sign of thrombogenesis. Upon evaluation of the clinical records, it became evident that, in addition to uterine atony, there had been a complete uterine inversion. This inversion was manually repositioned. After this maneuver, manual compression was performed. The <span class="hlt">air</span> embolism, thus, was a complication of the manual repositioning of the uterine inversion. There is no evidence for other possible entries of the detected gas. In order to perform an effective exploration, the availability of all clinical records should be mandatory for medico-legal investigations of unexpected postpartum deaths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3837826','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3837826"><span>Release of Free DNA by Membrane-Impaired Bacterial Aerosols <span class="hlt">Due</span> to Aerosolization and <span class="hlt">Air</span> Sampling</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhen, Huajun; Han, Taewon; Fennell, Donna E.</p> <p>2013-01-01</p> <p>We report here that stress experienced by bacteria <span class="hlt">due</span> to aerosolization and <span class="hlt">air</span> sampling can result in severe membrane impairment, leading to the release of DNA as free molecules. Escherichia coli and Bacillus atrophaeus bacteria were aerosolized and then either collected directly into liquid or collected using other collection media and then transferred into liquid. The amount of DNA released was quantified as the cell membrane damage index (ID), i.e., the number of 16S rRNA gene copies in the supernatant liquid relative to the total number in the bioaerosol sample. During aerosolization by a Collison nebulizer, the ID of E. coli and B. atrophaeus in the nebulizer suspension gradually increased during 60 min of continuous aerosolization. We found that the ID of bacteria during aerosolization was statistically significantly affected by the material of the Collison jar (glass > polycarbonate; P < 0.001) and by the bacterial species (E. coli > B. atrophaeus; P < 0.001). When E. coli was collected for 5 min by filtration, impaction, and impingement, its ID values were within the following ranges: 0.051 to 0.085, 0.16 to 0.37, and 0.068 to 0.23, respectively; when it was collected by electrostatic precipitation, the ID values (0.011 to 0.034) were significantly lower (P < 0.05) than those with other sampling methods. <span class="hlt">Air</span> samples collected inside an equine facility for 2 h by filtration and impingement exhibited ID values in the range of 0.30 to 0.54. The data indicate that the amount of cell damage during bioaerosol sampling and the resulting release of DNA can be substantial and that this should be taken into account when analyzing bioaerosol samples. PMID:24096426</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1047632','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1047632"><span><span class="hlt">Air-Flow</span> Navigated Crystal Growth for TIPS Pentacene-Based Organic Thin-Film Transistors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>He, Zhengran; Chen, Jihua; Sun, Zhenzhong; Szulczewski, Greg; Li, Dawen</p> <p>2012-01-01</p> <p>6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) is a promising active channel material of organic thin-film transistors (OTFTs) <span class="hlt">due</span> to its solubility, stability, and high mobility. However, the growth of TIPS pentacene crystals is intrinsically anisotropic and thus leads to significant variation in the performance of OTFTs. In this paper, <span class="hlt">air</span> <span class="hlt">flow</span> is utilized to effectively reduce the TIPS pentacene crystal anisotropy and enhance performance consistency in OTFTs, and the resulted films are examined with optical microscopy, grazing-incidence X-ray diffraction, and thin-film transistor measurements. Under <span class="hlt">air-flow</span> navigation (AFN), TIPS pentacene drop-cast from toluene solution has been observed to form thin films with improved crystal orientation and increased areal coverage on substrates, which subsequently lead to a four-fold increase of average hole mobility and one order of magnitude enhancement in performance consistency defined by the ratio of average mobility to the standard deviation of the field-effect mobilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ThEng..64...53V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ThEng..64...53V"><span>Ignition of an organic water-coal fuel droplet floating in a heated-<span class="hlt">air</span> <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valiullin, T. R.; Strizhak, P. A.; Shevyrev, S. A.; Bogomolov, A. R.</p> <p>2017-01-01</p> <p>Ignition of an organic water-coal fuel (CWSP) droplet floating in a heated-<span class="hlt">air</span> <span class="hlt">flow</span> has been studied experimentally. Rank B2 brown-coal particles with a size of 100 μm, used crankcase Total oil, water, and a plasticizer were used as the main CWSP components. A dedicated quartz-glass chamber has been designed with inlet and outlet elements made as truncated cones connected via a cylindrical ring. The cones were used to shape an oxidizer <span class="hlt">flow</span> with a temperature of 500-830 K and a <span class="hlt">flow</span> velocity of 0.5-5.0 m/s. A technique that uses a coordinate-positioning gear, a nichrome thread, and a cutter element has been developed for discharging CWSP droplets into the working zone of the chamber. Droplets with an initial size of 0.4 to 2.0 mm were used. Conditions have been determined for a droplet to float in the oxidizer <span class="hlt">flow</span> long enough for the sustainable droplet burning to be initiated. Typical stages and integral ignition characteristics have been established. The integral parameters (ignition-delay times) of the examined processes have been compared to the results of experiments with CWSP droplets suspended on the junction of a quick-response thermocouple. It has been shown that floating fuel droplets ignite much quicker than the ones that sit still on the thermocouple <span class="hlt">due</span> to rotation of an CWSP droplet in the oxidizer <span class="hlt">flow</span>, more uniform heating of the droplet, and lack of heat drainage towards the droplet center. High-speed video recording of the peculiarities of floatation of a burning fuel droplet makes it possible to complement the existing models of water-coal fuel burning. The results can be used for a more substantiated modeling of furnace CWSP burning with the ANSYS, Fluent, and Sigma-<span class="hlt">Flow</span> software packages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12659540','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12659540"><span>Changes in tropospheric composition and <span class="hlt">air</span> quality <span class="hlt">due</span> to stratospheric ozone depletion.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Solomon, Keith R; Tang, Xiaoyan; Wilson, Stephen R; Zanis, Prodromos; Bais, Alkiviadis F</p> <p>2003-01-01</p> <p>Increased UV-B through stratospheric ozone depletion leads to an increased chemical activity in the lower atmosphere (the troposphere). The effect of stratospheric ozone depletion on tropospheric ozone is small (though significant) compared to the ozone generated anthropogenically in areas already experiencing <span class="hlt">air</span> pollution. Modeling and experimental studies suggest that the impacts of stratospheric ozone depletion on tropospheric ozone are different at different altitudes and for different chemical regimes. As a result the increase in ozone <span class="hlt">due</span> to stratospheric ozone depletion may be greater in polluted regions. Attributable effects on concentrations are expected only in regions where local emissions make minor contributions. The vertical distribution of NOx (NO + NO2), the emission of volatile organic compounds and the abundance of water vapor, are important influencing factors. The long-term nature of stratospheric ozone depletion means that even a small increase in tropospheric ozone concentration can have a significant impact on human health and the environment. Trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA) are produced by the atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). TFA has been measured in rain, rivers, lakes, and oceans, the ultimate sink for these and related compounds. Significant anthropogenic sources of TFA other than degradation HCFCs and HFCs have been identified. Toxicity tests under field conditions indicate that the concentrations of TFA and CDFA currently produced by the atmospheric degradation of HFCs and HCFCs do not present a risk to human health and the environment. The impact of the interaction between ozone depletion and future climate change is complex and a significant area of current research. For <span class="hlt">air</span> quality and tropospheric composition, a range of physical parameters such as temperature, cloudiness and atmospheric transport will modify the impact of UV-B. Changes in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25981939','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25981939"><span>Cost saving potential in cardiovascular hospital costs <span class="hlt">due</span> to reduction in <span class="hlt">air</span> pollution.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Devos, Stefanie; Cox, Bianca; Dhondt, Stijn; Nawrot, Tim; Putman, Koen</p> <p>2015-09-15</p> <p>We describe a methodological framework to estimate potential cost savings in Belgium for a decrease in cardiovascular emergency admissions (ischemic heart disease (IHD), heart rhythm disturbances (HRD), and heart failure) <span class="hlt">due</span> to a reduction in <span class="hlt">air</span> pollution. Hospital discharge data on emergency admissions from an academic hospital were used to identify cases, derive risk functions, and estimate hospital costs. Risk functions were derived with case-crossover analyses with weekly average PM10, PM2.5, and NO2 exposures. The risk functions were subsequently used in a micro-costing analysis approach. Annual hospital cost savings for Belgium were estimated for two scenarios on the decrease of <span class="hlt">air</span> pollution: 1) 10% reduction in each of the pollutants and 2) reduction towards annual WHO guidelines. Emergency admissions for IHD and HRD were significantly associated with PM10, PM2.5, and NO2 exposures the week before admission. The estimated risk reduction for IHD admissions was 2.44% [95% confidence interval (CI): 0.33%-4.50%], 2.34% [95% CI: 0.62%-4.03%], and 3.93% [95% CI: 1.14%-6.65%] for a 10% reduction in PM10, PM2.5, and NO2 respectively. For Belgium, the associated annual cost savings were estimated at € 5.2 million, € 5.0 million, and € 8.4 million respectively. For HRD, admission risk could be reduced by 2.16% [95% CI: 0.14%-4.15%], 2.08% [95% CI: 0.42%-3.70%], and 3.46% [95% CI: 0.84%-6.01%] for a 10% reduction in PM10, PM2.5, and NO2 respectively. This corresponds with a potential annual hospital cost saving in Belgium of € 3.7 million, € 3.6 million, and € 5.9 million respectively. If WHO annual guidelines for PM10 and PM2.5 are met, more than triple these amounts would be saved. This study demonstrates that a model chain of case-crossover and micro-costing analyses can be applied in order to obtain estimates on the impact of <span class="hlt">air</span> pollution on hospital costs. Copyright © 2015 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/778926','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/778926"><span>Death, Disease, and Dirty Power. Mortality and health damage <span class="hlt">due</span> to <span class="hlt">air</span> pollution from power plants</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schneider, Conrad G.</p> <p>2000-10-01</p> <p>The Clean <span class="hlt">Air</span> Task Force, on behalf of the Clear the <span class="hlt">Air</span> campaign, commissioned Abt Associates to quantify the health impacts of fine particle <span class="hlt">air</span> pollution, commonly known as soot, from power plants, as well as the expected benefits (avoidable deaths, hospitalizations, etc.) of policies that would reduce fine particle pollution from power plants. The health effects analyzed include death, hospitalizations, emergency room visits, asthma attacks, and a variety of lesser respiratory symptoms. This report summarizes the findings of the Abt Associates study, reviews the contribution of power plants to fine particle pollution, and discusses policies that will reduce power plant fine particle pollution and thus save thousands of lives. Key findings include: Fine particle pollution from US power plants cuts short the lives of over 30,000 people each year. In more polluted areas, fine particle pollution can shave several years off its victims' lives. Hundreds of thousands of Americans suffer from asthma attacks, cardiac problems and upper and lower respiratory problems associated with fine particles from power plants. The elderly, children, and those with respiratory disease are most severely impacted by fine particle pollution from power plants. Metropolitan areas with large populations near coal-fired power plants feel their impacts most acutely - their attributable death rates are much higher than in areas with few or no coal-fired power plants. Power plants outstrip all other polluters as the largest source of sulfates - the major component of fine particle pollution - in the US Approximately two-thirds (over 18,000) of the deaths <span class="hlt">due</span> to fine particle pollution from power plants could be avoided by implementing policies that cut power plant sulfur dioxide and nitrogen oxide pollution 75 percent below 1997 emission levels. Fine particle pollution is responsible for increased risk of death and shortened life spans. Abt Associates' findings are based on a body of well</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA226389','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA226389"><span>Ultraviolet Excimer Laser-Based Ignition of H2/<span class="hlt">Air</span> and H2/O2 Premixed <span class="hlt">Flows</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1990-08-01</p> <p>minimum occurring for lean mixtures. The ignition is <span class="hlt">due</span> to efficient formation of microplasmas . Unlike the laser-produced microplasmas that are formed...<span class="hlt">Air</span> Ignition by the ArF Excimer Lasero... ... .o.2 B. Microplasma Formation Mechanism ....... o...... ..... .o.o....2 C. Atmospheric Absorption...Ratio for H2/02 Premixed <span class="hlt">Flows</span> Using ArF Laser (193 nm) (Unstable Resonator) ............... 3 2 Excitation Spectra for Microplasma Formation in H2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/116257','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/116257"><span>Correlations for film regeneration and <span class="hlt">air</span> dehumidification for a falling desiccant film with <span class="hlt">air</span> in cross <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Park, M.S.; Howell, J.R.; Vliet, G.C.</p> <p>1995-11-01</p> <p>The coupled heat and mass transfer between a falling triethylene glycol (TEG) desiccant film and <span class="hlt">air</span> in cross <span class="hlt">flow</span> have previously been presented and solved numerically for the cases of regeneration and dehumidification. Here, correlations for the effects of independent variables on the rate of regeneration in the regenerator and on the rate of dehumidification and sensible cooling in the absorber are developed by statistical analysis of the numerical results. The functional correlations developed should be useful in the design of regenerators and absorbers having falling liquid desiccant films and <span class="hlt">air</span> in cross <span class="hlt">flow</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title42-vol1/pdf/CFR-2011-title42-vol1-sec84-155.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title42-vol1/pdf/CFR-2011-title42-vol1-sec84-155.pdf"><span>42 CFR 84.155 - Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 42 Public Health 1 2011-10-01 2011-10-01 false Airflow resistance test; Type C supplied-<span class="hlt">air</span>... Respirators § 84.155 Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE supplied-<span class="hlt">air</span> respirator; minimum requirements. The resistance to <span class="hlt">air</span> <span class="hlt">flowing</span> from the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title42-vol1/pdf/CFR-2010-title42-vol1-sec84-155.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title42-vol1/pdf/CFR-2010-title42-vol1-sec84-155.pdf"><span>42 CFR 84.155 - Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 42 Public Health 1 2010-10-01 2010-10-01 false Airflow resistance test; Type C supplied-<span class="hlt">air</span>... Respirators § 84.155 Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE supplied-<span class="hlt">air</span> respirator; minimum requirements. The resistance to <span class="hlt">air</span> <span class="hlt">flowing</span> from the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title42-vol1/pdf/CFR-2012-title42-vol1-sec84-155.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title42-vol1/pdf/CFR-2012-title42-vol1-sec84-155.pdf"><span>42 CFR 84.155 - Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 42 Public Health 1 2012-10-01 2012-10-01 false Airflow resistance test; Type C supplied-<span class="hlt">air</span>... Respirators § 84.155 Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE supplied-<span class="hlt">air</span> respirator; minimum requirements. The resistance to <span class="hlt">air</span> <span class="hlt">flowing</span> from the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title42-vol1/pdf/CFR-2013-title42-vol1-sec84-155.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title42-vol1/pdf/CFR-2013-title42-vol1-sec84-155.pdf"><span>42 CFR 84.155 - Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 42 Public Health 1 2013-10-01 2013-10-01 false Airflow resistance test; Type C supplied-<span class="hlt">air</span>... Respirators § 84.155 Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE supplied-<span class="hlt">air</span> respirator; minimum requirements. The resistance to <span class="hlt">air</span> <span class="hlt">flowing</span> from the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title42-vol1/pdf/CFR-2014-title42-vol1-sec84-155.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title42-vol1/pdf/CFR-2014-title42-vol1-sec84-155.pdf"><span>42 CFR 84.155 - Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 42 Public Health 1 2014-10-01 2014-10-01 false Airflow resistance test; Type C supplied-<span class="hlt">air</span>... Respirators § 84.155 Airflow resistance test; Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class and Type CE supplied-<span class="hlt">air</span> respirator; minimum requirements. The resistance to <span class="hlt">air</span> <span class="hlt">flowing</span> from the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750013493','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750013493"><span>Program and charts for determining shock tube, and expansion tunnel <span class="hlt">flow</span> quantities for real <span class="hlt">air</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, C. G., III; Wilder, S. E.</p> <p>1975-01-01</p> <p>A computer program in FORTRAN 4 language was written to determine shock tube, expansion tube, and expansion tunnel <span class="hlt">flow</span> quantities for real-<span class="hlt">air</span> test gas. This program permits, as input data, a number of possible combinations of <span class="hlt">flow</span> quantities generally measured during a test. The versatility of the program is enhanced by the inclusion of such effects as a standing or totally reflected shock at the secondary diaphragm, thermochemical-equilibrium <span class="hlt">flow</span> expansion and frozen <span class="hlt">flow</span> expansion for the expansion tube and expansion tunnel, attenuation of the <span class="hlt">flow</span> in traversing the acceleration section of the expansion tube, real <span class="hlt">air</span> as the acceleration gas, and the effect of wall boundary layer on the acceleration section <span class="hlt">air</span> <span class="hlt">flow</span>. Charts which provide a rapid estimation of expansion tube performance prior to a test are included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21223040','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21223040"><span>Forced convective <span class="hlt">flow</span> and heat transfer of upward cocurrent <span class="hlt">air</span>-water slug <span class="hlt">flow</span> in vertical plain and swirl tubes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chang, Shyy Woei; Yang, Tsun Lirng</p> <p>2009-10-15</p> <p>This experimental study comparatively examined the two-phase <span class="hlt">flow</span> structures, pressured drops and heat transfer performances for the cocurrent <span class="hlt">air</span>-water slug <span class="hlt">flows</span> in the vertical tubes with and without the spiky twisted tape insert. The two-phase <span class="hlt">flow</span> structures in the plain and swirl tubes were imaged using the computerized high frame-rate videography with the Taylor bubble velocity measured. Superficial liquid Reynolds number (Re{sub L}) and <span class="hlt">air</span>-to-water mass <span class="hlt">flow</span> ratio (AW), which were respectively in the ranges of 4000-10000 and 0.003-0.02 were selected as the controlling parameters to specify the <span class="hlt">flow</span> condition and derive the heat transfer correlations. Tube-wise averaged void fraction and Taylor bubble velocity were well correlated by the modified drift flux models for both plain and swirl tubes at the slug <span class="hlt">flow</span> condition. A set of selected data obtained from the plain and swirl tubes was comparatively examined to highlight the impacts of the spiky twisted tape on the <span class="hlt">air</span>-water interfacial structure and the pressure drop and heat transfer performances. Empirical heat transfer correlations that permitted the evaluation of individual and interdependent Re{sub L} and AW impacts on heat transfer in the developed <span class="hlt">flow</span> regions of the plain and swirl tubes at the slug <span class="hlt">flow</span> condition were derived. (author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4674590','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4674590"><span>Cerebral Venous <span class="hlt">Air</span> Embolism <span class="hlt">due</span> to a Hidden Skull Fracture Secondary to Head Trauma</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hosaka, Ai; Yamaguchi, Tetsuto; Yamamoto, Fumiko; Shibagaki, Yasuro</p> <p>2015-01-01</p> <p>Cerebral venous <span class="hlt">air</span> embolism is sometimes caused by head trauma. One of the paths of <span class="hlt">air</span> entry is considered a skull fracture. We report a case of cerebral venous <span class="hlt">air</span> embolism following head trauma. The patient was a 55-year-old man who fell and hit his head. A head computed tomography (CT) scan showed the <span class="hlt">air</span> in the superior sagittal sinus; however, no skull fractures were detected. Follow-up CT revealed a fracture line in the right temporal bone. Cerebral venous <span class="hlt">air</span> embolism following head trauma might have occult skull fractures even if CT could not show the skull fractures. PMID:26693366</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ZNatA..72..833S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ZNatA..72..833S"><span><span class="hlt">Flow</span> and Heat Transfer in a Newtonian Nanoliquid <span class="hlt">due</span> to a Curved Stretching Sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siddheshwar, Pradeep Ganapathi; Nerolu, Meenakshi; Pažanin, Igor</p> <p>2017-08-01</p> <p><span class="hlt">Flow</span> of a Newtonian nanoliquid <span class="hlt">due</span> to a curved stretching sheet and heat transfer in it is studied. The governing nonlinear partial differential equations are reduced to nonlinear ordinary differential equations with variable coefficients by using a similarity transformation. The <span class="hlt">flow</span> characteristics are studied using plots of <span class="hlt">flow</span> velocity components and the skin-friction coefficient as a function of suction-injection parameter, curvature, and volume fraction. Prescribed surface temperature and prescribed surface heat flux are considered for studying the temperature distribution in the <span class="hlt">flow</span>. The thermophysical properties of 20 nanoliquids are considered in the investigation by modeling them through the use of phenomenological laws and mixture theory. The results of the corresponding problem involving a plane stretching sheet is obtained as a particular case of those obtained in the present paper. Skin friction coefficient and Nusselt number are evaluated and it is observed that skin friction coefficient decreases with concentration of nanoparticles in the absence as well as presence of suction where as Nusselt number increases with increase in concentration of nanoparticles in a dilute range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.H53B0457S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.H53B0457S"><span>Timescales of stream bed stabilization <span class="hlt">due</span> to altered <span class="hlt">flow</span> and sediment regimes below dams</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salant, N.; Renshaw, C.; Magilligan, F.</p> <p>2005-12-01</p> <p>Altered <span class="hlt">flow</span> and sediment transport regimes <span class="hlt">due</span> to impoundment can result in significant channel bed composition changes which exacerbate the geomorphic and ecological effects of <span class="hlt">flow</span> regulation. Using long-term discharge and cross-sectional data in combination with a two-fraction sediment transport model, we assess changes in the downstream bed of two <span class="hlt">flow</span>-regulated rivers with equivalent dam-induced changes in <span class="hlt">flow</span> but opposite changes in sediment flux. Supply limitation has led to incision and armoring in one case while supply excess has led to aggradation and embeddedness in the other. Under limited sediment supply, bed elevation variability decreases soon after impoundment, while excess sediment supply results in a decades-long gradual decrease in both bed elevation variability and depth of incision. Although the balance of sediment supply and transport differs between dam managements styles, both the immediate and more gradual changes can be explained within the framework of a two-fraction sediment transport model. Our results demonstrate the importance of considering bed composition on sediment transport predictions and the development of management strategies for ecosystem maintenance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010E%26ES...12a2030C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010E%26ES...12a2030C"><span>Performance improvement of a cross-<span class="hlt">flow</span> hydro turbine by <span class="hlt">air</span> layer effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, Y. D.; Yoon, H. Y.; Inagaki, M.; Ooike, S.; Kim, Y. J.; Lee, Y. H.</p> <p>2010-08-01</p> <p>The purpose of this study is not only to investigate the effects of <span class="hlt">air</span> layer in the turbine chamber on the performance and internal <span class="hlt">flow</span> of the cross-<span class="hlt">flow</span> turbine, but also to suggest a newly developed <span class="hlt">air</span> supply method. Field test is performed in order to measure the output power of the turbine by a new <span class="hlt">air</span> supply method. CFD analysis on the performance and internal <span class="hlt">flow</span> of the turbine is conducted by an unsteady state calculation using a two-phase <span class="hlt">flow</span> model in order to embody the <span class="hlt">air</span> layer effect on the turbine performance effectively.The result shows that <span class="hlt">air</span> layer effect on the performance of the turbine is considerable. The <span class="hlt">air</span> layer located in the turbine runner passage plays the role of preventing a shock loss at the runner axis and suppressing a recirculation <span class="hlt">flow</span> in the runner. The location of <span class="hlt">air</span> suction hole on the chamber wall is very important factor for the performance improvement. Moreover, the ratio between <span class="hlt">air</span> from suction pipe and water from turbine inlet is also significant factor of the turbine performance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1242416','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1242416"><span>LABORATORY EVALUATION OF <span class="hlt">AIR</span> <span class="hlt">FLOW</span> MEASUREMENT METHODS FOR RESIDENTIAL HVAC RETURNS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Walker, Iain; Stratton, Chris</p> <p>2015-02-01</p> <p>This project improved the accuracy of <span class="hlt">air</span> <span class="hlt">flow</span> measurements used in commissioning California heating and <span class="hlt">air</span> conditioning systems in Title 24 (Building and Appliance Efficiency Standards), thereby improving system performance and efficiency of California residences. The research team at Lawrence Berkeley National Laboratory addressed the issue that typical tools used by contractors in the field to test <span class="hlt">air</span> <span class="hlt">flows</span> may not be accurate enough to measure return <span class="hlt">flows</span> used in Title 24 applications. The team developed guidance on performance of current diagnostics as well as a draft test method for use in future evaluations. The series of tests performed measured <span class="hlt">air</span> <span class="hlt">flow</span> using a range of techniques and devices. The measured <span class="hlt">air</span> <span class="hlt">flows</span> were compared to reference <span class="hlt">air</span> <span class="hlt">flow</span> measurements using inline <span class="hlt">air</span> <span class="hlt">flow</span> meters built into the test apparatus. The experimental results showed that some devices had reasonable results (typical errors of 5 percent or less) but others had much bigger errors (up to 25 percent). Because manufacturers’ accuracy estimates for their equipment do not include many of the sources of error found in actual field measurements (and replicated in the laboratory testing in this study) it is essential for a test method that could be used to determine the actual uncertainty in this specific application. The study team prepared a draft test method through ASTM International to determine the uncertainty of <span class="hlt">air</span> <span class="hlt">flow</span> measurements at residential heating ventilation and <span class="hlt">air</span> conditioning returns and other terminals. This test method, when finalized, can be used by the Energy Commission and other entities to specify required accuracy of measurement devices used to show compliance with standards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20673952','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20673952"><span>Effect of <span class="hlt">air-flow</span> rate and turning frequency on bio-drying of dewatered sludge.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Ling; Gu, Wei-Mei; He, Pin-Jing; Shao, Li-Ming</p> <p>2010-12-01</p> <p>Sludge bio-drying is an approach for biomass energy utilization, in which sludge is dried by means of the heat generated by aerobic degradation of its organic substances. The study aimed at investigating the interactive influence of <span class="hlt">air-flow</span> rate and turning frequency on water removal and biomass energy utilization. Results showed that a higher <span class="hlt">air-flow</span> rate (0.0909m(3)h(-1)kg(-1)) led to lower temperature than did the lower one (0.0455m(3)h(-1)kg(-1)) by 17.0% and 13.7% under turning per two days and four days. With the higher <span class="hlt">air-flow</span> rate and lower turning frequency, temperature cumulation was almost similar to that with the lower <span class="hlt">air-flow</span> rate and higher turning frequency. The doubled <span class="hlt">air-flow</span> rate improved the total water removal ratio by 2.86% (19.5gkg(-1) initial water) and 11.5% (75.0gkg(-1) initial water) with turning per two days and four days respectively, indicating that there was no remarkable advantage for water removal with high <span class="hlt">air-flow</span> rate, especially with high turning frequency. The heat used for evaporation was 60.6-72.6% of the total heat consumption (34,400-45,400kJ). The higher <span class="hlt">air-flow</span> rate enhanced volatile solids (VS) degradation thus improving heat generation by 1.95% (800kJ) and 8.96% (3200kJ) with turning per two days and four days. With the higher <span class="hlt">air-flow</span> rate, heat consumed by sensible heat of inlet <span class="hlt">air</span> and heat utilization efficiency for evaporation was higher than the lower one. With the higher turning frequency, sensible heat of materials and heat consumed by turning was higher than lower one.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28672674','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28672674"><span>Disease burden <span class="hlt">due</span> to biomass cooking-fuel-related household <span class="hlt">air</span> pollution among women in India.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sehgal, Meena; Rizwan, Suliankatchi Abdulkader; Krishnan, Anand</p> <p>2014-12-01</p> <p>Background Household <span class="hlt">air</span> pollution (HAP) <span class="hlt">due</span> to biomass cooking fuel use is an important risk factor for a range of diseases, especially among adult women who are primary cooks, in India. About 80% of rural households in India use biomass fuel for cooking. The aim of this study is to estimate the attributable cases (AC) for four major diseases/conditions associated with biomass cooking fuel use among adult Indian women. Methods We used the population attributable fraction (PAF) method to calculate the AC of chronic bronchitis, tuberculosis (TB), cataract, and stillbirths <span class="hlt">due</span> to exposure to biomass cooking fuel. A number of data sources were accessed to obtain population totals and disease prevalence rates. A meta-analysis was conducted to obtain adjusted pooled odds ratios (ORs) for strength of association. Using this, PAF and AC were calculated using a standard formula. Results were presented as number of AC and 95% confidence intervals (CI). Results The fixed effects pooled OR obtained from the meta-analysis were 2.37 (95% CI: 1.59, 3.54) for chronic bronchitis, 2.33 (1.65, 3.28) for TB, 2.16 (1.42, 3.26) for cataract, and 1.26 (1.12, 1.43) for stillbirths. PAF varied across conditions being maximum (53%) for chronic bronchitis in rural areas and least (1%) for cataract in older age and urban areas. About 2.4 (95% CI: 1.4, 3.1) of 5.6 m cases of chronic bronchitis, 0.3 (0.2, 0.4) of 0.76 m cases of TB, 5.0 (2.8, 6.7) of 51.4 m cases of cataract among adult Indian women and 0.02 (0.01, 0.03) of 0.15 m stillbirths across India are attributable to HAP <span class="hlt">due</span> to biomass cooking fuel. These estimates should be cautiously interpreted in the light of limitations discussed which relate to exposure assessment, exposure characterization, and age-specific prevalence of disease. Conclusions HAP <span class="hlt">due</span> to biomass fuel has diverse and major impacts on women's health in India. Although challenging, incorporating the agenda of universal clean fuel access or cleaner technology within</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25373414','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25373414"><span>Disease burden <span class="hlt">due</span> to biomass cooking-fuel-related household <span class="hlt">air</span> pollution among women in India.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sehgal, Meena; Rizwan, Suliankatchi Abdulkader; Krishnan, Anand</p> <p>2014-01-01</p> <p>Household <span class="hlt">air</span> pollution (HAP) <span class="hlt">due</span> to biomass cooking fuel use is an important risk factor for a range of diseases, especially among adult women who are primary cooks, in India. About 80% of rural households in India use biomass fuel for cooking. The aim of this study is to estimate the attributable cases (AC) for four major diseases/conditions associated with biomass cooking fuel use among adult Indian women. We used the population attributable fraction (PAF) method to calculate the AC of chronic bronchitis, tuberculosis (TB), cataract, and stillbirths <span class="hlt">due</span> to exposure to biomass cooking fuel. A number of data sources were accessed to obtain population totals and disease prevalence rates. A meta-analysis was conducted to obtain adjusted pooled odds ratios (ORs) for strength of association. Using this, PAF and AC were calculated using a standard formula. Results were presented as number of AC and 95% confidence intervals (CI). The fixed effects pooled OR obtained from the meta-analysis were 2.37 (95% CI: 1.59, 3.54) for chronic bronchitis, 2.33 (1.65, 3.28) for TB, 2.16 (1.42, 3.26) for cataract, and 1.26 (1.12, 1.43) for stillbirths. PAF varied across conditions being maximum (53%) for chronic bronchitis in rural areas and least (1%) for cataract in older age and urban areas. About 2.4 (95% CI: 1.4, 3.1) of 5.6 m cases of chronic bronchitis, 0.3 (0.2, 0.4) of 0.76 m cases of TB, 5.0 (2.8, 6.7) of 51.4 m cases of cataract among adult Indian women and 0.02 (0.01, 0.03) of 0.15 m stillbirths across India are attributable to HAP <span class="hlt">due</span> to biomass cooking fuel. These estimates should be cautiously interpreted in the light of limitations discussed which relate to exposure assessment, exposure characterization, and age-specific prevalence of disease. HAP <span class="hlt">due</span> to biomass fuel has diverse and major impacts on women's health in India. Although challenging, incorporating the agenda of universal clean fuel access or cleaner technology within the broader framework of rural</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4221659','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4221659"><span>Disease burden <span class="hlt">due</span> to biomass cooking-fuel-related household <span class="hlt">air</span> pollution among women in India</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sehgal, Meena; Rizwan, Suliankatchi Abdulkader; Krishnan, Anand</p> <p>2014-01-01</p> <p>Background Household <span class="hlt">air</span> pollution (HAP) <span class="hlt">due</span> to biomass cooking fuel use is an important risk factor for a range of diseases, especially among adult women who are primary cooks, in India. About 80% of rural households in India use biomass fuel for cooking. The aim of this study is to estimate the attributable cases (AC) for four major diseases/conditions associated with biomass cooking fuel use among adult Indian women. Methods We used the population attributable fraction (PAF) method to calculate the AC of chronic bronchitis, tuberculosis (TB), cataract, and stillbirths <span class="hlt">due</span> to exposure to biomass cooking fuel. A number of data sources were accessed to obtain population totals and disease prevalence rates. A meta-analysis was conducted to obtain adjusted pooled odds ratios (ORs) for strength of association. Using this, PAF and AC were calculated using a standard formula. Results were presented as number of AC and 95% confidence intervals (CI). Results The fixed effects pooled OR obtained from the meta-analysis were 2.37 (95% CI: 1.59, 3.54) for chronic bronchitis, 2.33 (1.65, 3.28) for TB, 2.16 (1.42, 3.26) for cataract, and 1.26 (1.12, 1.43) for stillbirths. PAF varied across conditions being maximum (53%) for chronic bronchitis in rural areas and least (1%) for cataract in older age and urban areas. About 2.4 (95% CI: 1.4, 3.1) of 5.6 m cases of chronic bronchitis, 0.3 (0.2, 0.4) of 0.76 m cases of TB, 5.0 (2.8, 6.7) of 51.4 m cases of cataract among adult Indian women and 0.02 (0.01, 0.03) of 0.15 m stillbirths across India are attributable to HAP <span class="hlt">due</span> to biomass cooking fuel. These estimates should be cautiously interpreted in the light of limitations discussed which relate to exposure assessment, exposure characterization, and age-specific prevalence of disease. Conclusions HAP <span class="hlt">due</span> to biomass fuel has diverse and major impacts on women’s health in India. Although challenging, incorporating the agenda of universal clean fuel access or cleaner technology within</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22493925','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22493925"><span>Magnetohydrodynamic (MHD) <span class="hlt">flow</span> of Cu-water nanofluid <span class="hlt">due</span> to a rotating disk with partial slip</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hayat, Tasawar; Rashid, Madiha; Imtiaz, Maria; Alsaedi, Ahmed</p> <p>2015-06-15</p> <p>This paper investigates MHD steady <span class="hlt">flow</span> of viscous nanofluid <span class="hlt">due</span> to a rotating disk. Water is treated as a base fluid and copper as nanoparticle. Nanofluid fills the porous medium. Effects of partial slip, viscous dissipation and thermal radiation are also considered. Similarity transformations reduce the nonlinear partial differential equations to ordinary differential equations. <span class="hlt">Flow</span> and heat transfer characteristics are computed by HAM solutions. Also computations for skin friction coefficient and Nusselt number are presented and examined for pertinent parameters. It is noted that higher velocity slip parameter decreases the radial and azimuthal velocities while temperature decreases for larger values of the thermal slip parameter. Also the rate of heat transfer enhances when the nanoparticle volume fraction increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AtmEn..35.4763S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AtmEn..35.4763S"><span>Damage costs <span class="hlt">due</span> to automotive <span class="hlt">air</span> pollution and the influence of street canyons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spadaro, Joseph V.; Rabl, Ari</p> <p></p> <p>Using the methodology of the ExternE Project of the European Commission, we have evaluated the damage costs of automotive <span class="hlt">air</span> pollution by way of two case studies in France: a trip across Paris, and a trip from Paris to Lyon. This methodology involves an analysis of the impact pathways, starting with the emissions (e.g., g/km of particles from tailpipe), followed by local and regional dispersion (e.g., incremental μg/m 3 of particles), calculation of the physical impacts using exposure-response functions (e.g., cases of respiratory hospital admissions), and finally multiplication by unit costs factors (e.g., ? per hospital admission). Damages are aggregated over all affected receptors in Europe. In addition to the local and regional dispersion calculations carried out so far by ExternE, we also consider the increased microscale impacts <span class="hlt">due</span> to the trapping of pollutants in street canyons, using numerical simulations with the FLUENT software. We have evaluated impacts to human health, agricultural crops and building materials, <span class="hlt">due</span> to particles, NO x, CO, HC and CO 2. Health impacts, especially reduced life expectancy, dominate in terms of cost. Damages for older cars (before 1997) range from 2 to 41 Euro cents/km, whereas for newer cars (since 1997), the range 1-9 Euro cents/km, and there is continuing progress in reducing the emissions further. In large cities, the particulate emissions of diesel cars lead to the highest damages, exceeding those of gasoline cars by a factor of 7. For cars before 1997 the order of magnitude of the damage costs is comparable to the price of gasoline, and the loss of life expectancy is comparable to that from traffic accidents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6790033','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6790033"><span>Pulsed-<span class="hlt">flow</span> <span class="hlt">air</span> classification for waste to energy production. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Peirce, J.J.; Vesilind, P.A.</p> <p>1983-09-30</p> <p>The development and testing of pulsed-<span class="hlt">flow</span> <span class="hlt">air</span> classification for waste-to-energy production are discussed. Standard designs generally permit large amounts of combustible material to escape as reject while producing a fuel that is high in metal and glass contaminants. Pulsed-<span class="hlt">flow</span> classification is presented as a concept which can avoid both pitfalls. Each aspect of theory and laboratory testing is summarized: particle characteristics, theory of pulsed-<span class="hlt">flow</span> classification, laboratory testing, and pulsed-<span class="hlt">flow</span> <span class="hlt">air</span> classification for waste-to-energy production. Conclusions from the research are summarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28081900','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28081900"><span>Broadening of analyte streams <span class="hlt">due</span> to a transverse pressure gradient in free-<span class="hlt">flow</span> isoelectric focusing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dutta, Debashis</p> <p>2017-02-10</p> <p>Pressure-driven cross-<span class="hlt">flows</span> can arise in free-<span class="hlt">flow</span> isoelectric focusing systems (FFIEF) <span class="hlt">due</span> to a non-uniform electroosmotic <span class="hlt">flow</span> velocity along the channel width induced by the pH gradient in this direction. In addition, variations in the channel cross-section as well as unwanted differences in hydrostatic heads at the buffer/sample inlet ports can also lead to such pressure-gradients which besides altering the equilibrium position of the sample zones have a tendency to substantially broaden their widths deteriorating the separations. In this situation, a thorough assessment of stream broadening <span class="hlt">due</span> to transverse pressure-gradients in FFIEF devices is necessary in order to establish accurate design rules for the assay. The present article describes a mathematical framework to estimate the noted zone dispersion in FFIEF separations based on the method-of-moments approach under laminar <span class="hlt">flow</span> conditions. A closed-form expression has been derived for the spatial variance of the analyte streams at their equilibrium positions as a function of the various operating parameters governing the assay performance. This expression predicts the normalized stream variance under the chosen conditions to be determined by two dimensionless Péclet numbers evaluated based on the transverse pressure-driven and electrophoretic solute velocities in the separation chamber, respectively. Moreover, the analysis shows that while the stream width can be expected to increase with an increase in the value of the first Péclet number, the opposite trend will be followed with respect to the latter. The noted results have been validated using Monte Carlo simulations that also establish a time/length scale over which the predicted equilibrium stream width is attained in the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..233a2030D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..233a2030D"><span>Automatic device for indirect measurement of leakage <span class="hlt">flow</span> rate in compressed <span class="hlt">air</span> pipeline</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dindorf, R.; Wos, P.; Pawelec, K.</p> <p>2017-08-01</p> <p>The new measurement method of compressed <span class="hlt">air</span> leakage <span class="hlt">flow</span> rate in compressed <span class="hlt">air</span> pipeline is proposed. In this method, the automatic measuring device is connected to a branch of the pipeline. The measuring device can be used to measure compressed <span class="hlt">air</span> leakage in any place of compressed <span class="hlt">air</span> pipeline: in main line, distribution line and connection line. The proposed measurement methods of compressed <span class="hlt">air</span> leakage in pipeline are independent of receiver and compressor parameters, which is not the case with traditional method measuring leaks by emptying the receiver.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12756014','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12756014"><span><span class="hlt">Air</span> <span class="hlt">flow</span> and particle control with different ventilation systems in a classroom.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Holmberg, S; Chen, Q</p> <p>2003-06-01</p> <p>Most ventilation and <span class="hlt">air</span> conditioning systems are designed without much concern about how settling particles behave in ventilation <span class="hlt">air</span> <span class="hlt">flows</span>. For displacement ventilation systems, designers normally assume that all pollutants follow the buoyant <span class="hlt">air</span> <span class="hlt">flow</span> into an upper zone, where they are evacuated. This is, however, not always true. Previous studies show that high concentrations of settling respirable particles can be found in the breathing zone, and that the exposure rates can be a health hazard to occupants. The emphasis here is on how ventilation systems should be designed to minimize respirable airborne particles in the breathing zone. The supply and exhaust conditions of the ventilation <span class="hlt">air</span> <span class="hlt">flow</span> are shown to play an important role in the control of <span class="hlt">air</span> quality. Computer simulation programs of computational fluid dynamics (CFD) type are used. Particle concentrations, thermal conditions and modified ventilation system solutions are reported.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......186C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......186C"><span>Cloud-based large-scale <span class="hlt">air</span> traffic <span class="hlt">flow</span> optimization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cao, Yi</p> <p></p> <p>The ever-increasing traffic demand makes the efficient use of airspace an imperative mission, and this paper presents an effort in response to this call. Firstly, a new aggregate model, called Link Transmission Model (LTM), is proposed, which models the nationwide traffic as a network of flight routes identified by origin-destination pairs. The traversal time of a flight route is assumed to be the mode of distribution of historical flight records, and the mode is estimated by using Kernel Density Estimation. As this simplification abstracts away physical trajectory details, the complexity of modeling is drastically decreased, resulting in efficient traffic forecasting. The predicative capability of LTM is validated against recorded traffic data. Secondly, a nationwide traffic <span class="hlt">flow</span> optimization problem with airport and en route capacity constraints is formulated based on LTM. The optimization problem aims at alleviating traffic congestions with minimal global delays. This problem is intractable <span class="hlt">due</span> to millions of variables. A dual decomposition method is applied to decompose the large-scale problem such that the subproblems are solvable. However, the whole problem is still computational expensive to solve since each subproblem is an smaller integer programming problem that pursues integer solutions. Solving an integer programing problem is known to be far more time-consuming than solving its linear relaxation. In addition, sequential execution on a standalone computer leads to linear runtime increase when the problem size increases. To address the computational efficiency problem, a parallel computing framework is designed which accommodates concurrent executions via multithreading programming. The multithreaded version is compared with its monolithic version to show decreased runtime. Finally, an open-source cloud computing framework, Hadoop MapReduce, is employed for better scalability and reliability. This framework is an "off-the-shelf" parallel computing model</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JEPT...89.1212K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JEPT...89.1212K"><span>Hydraulic Resistance and Liberation of <span class="hlt">Air</span> in Aviation Kerosene <span class="hlt">Flow</span> Through Diaphragms at Low Pressure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kitanin, É. L.; Kitanina, E. É.; Zherebtsov, V. A.; Peganova, M. M.; Stepanov, S. G.; Bondarenko, D. A.; Morisson, D.</p> <p>2016-09-01</p> <p>This paper presents the results of experimental investigations of the liberation of <span class="hlt">air</span> in gravity <span class="hlt">flow</span> of aviation fuel through a pipeline with diaphragms. Experiments were carried out in the pressure range 0.2-1.0 bar and temperature range -20 to +20°C. The TC-1 kerosene was preliminarily saturated with <span class="hlt">air</span> at atmospheric pressure. The liberation of <span class="hlt">air</span> after the diaphragms with three ratios of the <span class="hlt">flow</span> area to the cross-sectional area of the pipeline has been investigated. The results of investigations of the two-phase <span class="hlt">flow</span> in several experimental pipelines containing one or two diaphragms and other local hydraulic resistances have been generalized. The obtained approximation equations permit calculating the hydraulic resistance of the diaphragm in the two-phase <span class="hlt">flow</span> and the mass gas content of <span class="hlt">air</span> after the diaphragm in pipelines of complex geometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JSASS..60...17N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JSASS..60...17N"><span>Decentralized Control of an Unidirectional <span class="hlt">Air</span> Traffic <span class="hlt">Flow</span> with Flight Speed Distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, Yoichi; Takeichi, Noboru</p> <p></p> <p>A decentralized control of an <span class="hlt">air</span> traffic <span class="hlt">flow</span> is discussed. This study aims to clarify a fundamental strategy for an unidirectional <span class="hlt">air</span> traffic <span class="hlt">flow</span> control considering the flight speed distribution. It is assumed that the decentralized control is made based on airborne surveillance systems. The separation control between aircraft is made by turning, and 4 types of route composition are compared; the optimum route only, the optimum route with permissible range, the optimum route with subroutes determined by relative speed of each aircraft, and the optimum route with subroutes defined according to the optimum speed of each aircraft. Through numerical simulations, it is clarified that the route composition with a permissible range makes the <span class="hlt">air</span> traffic <span class="hlt">flow</span> safer and more efficient. It is also shown that the route design with multiple subroutes corresponding to speed ranges and the aircraft control using route intent information can considerably improve the safety and workload of the <span class="hlt">air</span> traffic <span class="hlt">flow</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDR27009A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDR27009A"><span>Experimental study on bi-phase <span class="hlt">flow</span> <span class="hlt">Air</span>-Oil in Water Emulsion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arnone, Davide; Poesio, Pietro</p> <p>2015-11-01</p> <p>Bi-phase slug <span class="hlt">flow</span> oil-in-water emulsion [5%-20%] and <span class="hlt">air</span> through a horizontal pipe (inner diameter 22mm) is experimentally studied. A test with water and <span class="hlt">air</span> has been performed as comparison. First we create and analyze the <span class="hlt">flow</span> pattern map to identify slug <span class="hlt">flow</span> liquid and <span class="hlt">air</span> inlet conditions. <span class="hlt">Flow</span> maps are similar for all the used liquid. A video analysis procedure using an high speed camera has been created to obtain all the characteristics of unit slugs: slug velocity, slug length, bubble velocity, bubbles length and slug frequency. We compare translational velocity and frequency with models finding a good agreement. We calculate the pdfs of the lengths to find the correlations between mean values and STD on different <span class="hlt">air</span> and liquid superficial velocities. We also perform pressure measurements along the pipe. We conclude that the percentage of oil-in- water has no influence on results in terms of velocity, lengths, frequency and pressure drop.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22253102','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22253102"><span>Study of <span class="hlt">flow</span> fields induced by surface dielectric barrier discharge actuator in low-pressure <span class="hlt">air</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Che, Xueke E-mail: st@mail.iee.ac.cn; Nie, Wansheng; Tian, Xihui; Hou, Zhiyong; He, Haobo; Zhou, Penghui; Zhou, Siyin; Yang, Chao; Shao, Tao E-mail: st@mail.iee.ac.cn</p> <p>2014-04-15</p> <p>Surface dielectric barrier discharge (SDBD) is a promising method for a <span class="hlt">flow</span> control. <span class="hlt">Flow</span> fields induced by a SDBD actuator driven by the ac voltage in static <span class="hlt">air</span> at low pressures varying from 1.0 to 27.7 kPa are measured by the particle image velocimetry method. The influence of the applied ac voltage frequency and magnitude on the induced <span class="hlt">flow</span> fields is studied. The results show that three different classes of <span class="hlt">flow</span> fields (wall jet <span class="hlt">flow</span> field, complex <span class="hlt">flow</span> field, and vortex-shape <span class="hlt">flow</span> field) can be induced by the SDBD actuator in the low-pressure <span class="hlt">air</span>. Among them, the wall jet <span class="hlt">flow</span> field is the same as the tangential jet at atmospheric pressure, which is, together with the vertical jet, the complex <span class="hlt">flow</span> field. The vortex-shape <span class="hlt">flow</span> field is composed of one vertical jet which points towards the wall and two opposite tangential jets. The complex and the vortex-shape <span class="hlt">flow</span> fields can be transformed to the wall jet <span class="hlt">flow</span> field when the applied ac voltage frequency and magnitude are changed. It is found that the discharge power consumption increases initially, decreases, and then increases again at the same applied ac voltage magnitude when the <span class="hlt">air</span> pressure decreases. The tangential velocity of the wall jet <span class="hlt">flow</span> field increases when the <span class="hlt">air</span> pressure decreases. It is however opposite for the complex <span class="hlt">flow</span> field. The variation of the applied ac voltage frequency influences differently three different <span class="hlt">flow</span> fields. When the applied ac voltage magnitude increases at the same applied ac voltage frequency, the maximal jet velocity increases, while the power efficiency increases only initially and then decreases again. The discharge power shows either linear or exponential dependences on the applied ac voltage magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1513110V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1513110V"><span>Incipient motion in gravel bed rivers <span class="hlt">due</span> to energetic turbulent <span class="hlt">flow</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valyrakis, Manousos</p> <p>2013-04-01</p> <p>This contribution reviews recent developments and contributions in the field of incipient motion and entrainment of coarse sediment grains <span class="hlt">due</span> to the action of near bed turbulent <span class="hlt">flows</span>. Specifically, traditional shear based spatio-temporally averaged concepts and instantaneous stress tensor criteria are contrasted to the newly proposed <span class="hlt">flow</span> event based impulse and energy criteria. The energy criterion, suggests that only sufficiently energetic turbulent events can remove a particle from its resting position on the bed surface and result on its entrainment downstream. While the impulse and energy criteria are interconnected through the energy-impulse equation, the later appears to be more versatile and appropriate for generalising to sediment transport. These <span class="hlt">flow</span> event based criteria have a sound physical basis for describing the intermittent character of particle entrainment as inherited by near boundary turbulence at near threshold conditions. These criteria can be derived from fundamental laws of physics such as Newtonian classical mechanics and the Lagrange equations respectively. The energetic events that are capable of performing geomorphic work at the scale of individual particles are shown to follow a power law, meaning that more energetic events (capable of removing larger stones) are expected to occur less frequently. In addition, this paper discusses the role of the coefficient of energy transfer efficiency introduced in the energy equation for particle entrainment. A preliminary investigation from analysis of a series of mobile grain flume experiments illustrates that different signatures of turbulence or sequence of <span class="hlt">flow</span> structures may have different effectiveness towards particle transport. Characteristic cases of specific energetic <span class="hlt">flow</span> events and the associated particle response are shown and classified with regard to the time required for complete entrainment. Finally these findings are commented with respect to the implications for sediment</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H51D1225B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H51D1225B"><span>Small scale changes of geochemistry and <span class="hlt">flow</span> field <span class="hlt">due</span> to transient heat storage in aquifers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bauer, S.; Boockmeyer, A.; Li, D.; Beyer, C.</p> <p>2013-12-01</p> <p>Heat exchangers in the subsurface are increasingly installed for transient heat storage <span class="hlt">due</span> to the need of heating or cooling of buildings as well as the interim storage of heat to compensate for the temporally fluctuating energy production by wind or solar energy. For heat storage to be efficient, high temperatures must be achieved in the subsurface. Significant temporal changes of the soil and groundwater temperatures however effect both the local <span class="hlt">flow</span> field by temperature dependent fluid parameters as well as reactive mass transport through temperature dependent diffusion coefficients, geochemical reaction rates and mineral equilibria. As the use of heat storage will be concentrated in urban areas, the use of the subsurface for (drinking) water supply and heat storage will typically coincide and a reliable prognosis of the processes occurring is needed. In the present work, the effects of a temporal variation of the groundwater temperature, as induced by a local heat exchanger introduced into a groundwater aquifer, are studied. For this purpose, the coupled non-isothermal groundwater <span class="hlt">flow</span>, heat transport and reactive mass transport is simulated in the near filed of such a heat exchanger. By explicitly discretizing and incorporating the borehole, the borehole cementation and the heat exchanger tubes, a realistic geometrical and process representation is obtained. The numerical simulation code OpenGeoSys is used in this work, which incorporates the required processes of coupled groundwater <span class="hlt">flow</span>, heat and mass transport as well as temperature dependent geochemistry. <span class="hlt">Due</span> to the use of a Finite Element Method, a close representation of the geometric effects can be achieved. Synthetic scenario simulations for typical settings of salt water formations in northern Germany are used to investigate the geochemical effects arising from a high temperature heat storage by quantifying changes in groundwater chemistry and overall reaction rates. This work presents the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24665067','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24665067"><span>Bioinspired carbon nanotube fuzzy fiber hair sensor for <span class="hlt">air-flow</span> detection.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maschmann, Matthew R; Ehlert, Gregory J; Dickinson, Benjamin T; Phillips, David M; Ray, Cody W; Reich, Greg W; Baur, Jeffery W</p> <p>2014-05-28</p> <p>Artificial hair sensors consisting of a piezoresistive carbon-nanotube-coated glass fiber embedded in a microcapillary are assembled and characterized. Individual sensors resemble a hair plug that may be integrated in a wide range of host materials. The sensors demonstrate an <span class="hlt">air-flow</span> detection threshold of less than 1 m/s with a piezoresistive sensitivity of 1.3% per m/s <span class="hlt">air-flow</span> change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21435722','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21435722"><span><span class="hlt">Air</span> <span class="hlt">flow</span> and concentration fields at urban road intersections for improved understanding of personal exposure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tiwary, Abhishek; Robins, Alan; Namdeo, Anil; Bell, Margaret</p> <p>2011-07-01</p> <p>This paper reviews the state of knowledge on modelling <span class="hlt">air</span> <span class="hlt">flow</span> and concentration fields at road intersections. The first part covers the available literature from the past two decades on experimental (both field and wind tunnel) and modelling activities in order to provide insight into the physical basis of <span class="hlt">flow</span> behaviour at a typical cross-street intersection. This is followed by a review of associated investigations of the impact of traffic-generated localised turbulence on the concentration fields <span class="hlt">due</span> to emissions from vehicles. There is a discussion on the role of adequate characterisation of vehicle-induced turbulence in making predictions using hybrid models, combining the merits of conventional approaches with information obtained from more detailed modelling. This concludes that, despite advancements in computational techniques, there are crucial knowledge gaps affecting the parameterisations used in current models for individual exposure. This is specifically relevant to the growing impetus on walking and cycling activities on urban roads in the context of current drives for sustainable transport and healthy living. <span class="hlt">Due</span> to inherently longer travel times involved during such trips, compared to automotive transport, pedestrians and cyclists are subjected to higher levels of exposure to emissions. Current modelling tools seem to under-predict this exposure because of limitations in their design and in the empirical parameters employed. Copyright © 2011 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4940B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4940B"><span>Sele coastal plain flood risk <span class="hlt">due</span> to wave storm and river <span class="hlt">flow</span> interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benassai, Guido; Aucelli, Pietro; Di Paola, Gianluigi; Della Morte, Renata; Cozzolino, Luca; Rizzo, Angela</p> <p>2016-04-01</p> <p>-critical simulation, the boundary condition is a known downstream WSE, in this case the elevated water level <span class="hlt">due</span> to wave setup, wind setup and inverted barometer, while the upstream boundary condition consisted in WSE corresponding to river discharges associated to different return periods. The results of the simulations evidence, for the last 10 kilometers of the river, the burst of critical inundation scenarios even with moderate <span class="hlt">flow</span> discharge, if associated with concurrent storm surge which increase the water level at the river mouth, obstructing normal <span class="hlt">flow</span> discharge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPJWC.14003052A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPJWC.14003052A"><span>Discharge <span class="hlt">flow</span> of granular media from silos with a lateral orifice and injection of <span class="hlt">air</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aussillous, Pascale; Zhou, Yixian; Ruyer, Pierre; Lagrée, Pierre-Yves</p> <p>2017-06-01</p> <p>Few studies concern the prediction of the mass <span class="hlt">flow</span> rate of a granular media discharged from a silo with a lateral orifice. However, this situation can have pratical interest considering a tank of granular material with a leak on its side. We studied experimentally the discharge of a vertical silo filled by spherical glass beads. We consider rectangular silos with a rectangular orifice. The impact of size, aspect ratio and position of the orifice and the effect of an additional <span class="hlt">air</span> <span class="hlt">flow</span> were studied. The measured parameters are the mass <span class="hlt">flow</span> rate and the pressure along the silo, whereas the controlled parameters are the size of particles, and the <span class="hlt">flow</span> rate of <span class="hlt">air</span>. We identified two regimes of discharge according to the aspect ratio (of width to height) of the rectangular orifice. Increasing the <span class="hlt">air</span> <span class="hlt">flow</span> rate induces an increase of the granular media <span class="hlt">flow</span> rate. Using a simple physical model to describe the grains and gas <span class="hlt">flow</span>, we put in evidence the role played by the <span class="hlt">air</span> pressure gradient at the outlet. Then we compared the experimental results with continuum Navier-Stokes simulations with the granular μ(I)-rheology. We showed that the continuum μ(I)-rheology describes well our discharge <span class="hlt">flow</span> of granular media from silos, taking into account the effect of the position of the orifice as well as the coupling with the gas <span class="hlt">flow</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002A%26A...386..169L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002A%26A...386..169L"><span>Generation of galactic disc warps <span class="hlt">due</span> to intergalactic accretion <span class="hlt">flows</span> onto the disc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>López-Corredoira, M.; Betancort-Rijo, J.; Beckman, J. E.</p> <p>2002-04-01</p> <p>A new method is developed to calculate the amplitude of the galactic warps generated by a torque <span class="hlt">due</span> to external forces. This takes into account that the warp is produced as a reorientation of the different rings which constitute the disc in order to compensate the differential precession generated by the external force, yielding a uniform asymptotic precession for all rings. Application of this method to gravitational tidal forces in the Milky Way <span class="hlt">due</span> to the Magellanic Clouds leads to a very low amplitude of the warp, as has been inferred in previous studies; so, tidal forces are unlikely to generate warps, at least in the Milky Way. If the force were <span class="hlt">due</span> to an extragalactic magnetic field, its intensity would have to be very high, greater than 1 mu G, to generate the observed warps. An alternative hypothesis is explored: the accretion of the intergalactic medium over the disk. A cup-shaped distortion is expected, <span class="hlt">due</span> to the transmission of the linear momentum; but, this effect is small and the predominant effect turns out to be the transmission of angular momentum, i.e. a torque giving an integral-sign shape warp. The torque produced by a <span class="hlt">flow</span> of velocity ~ 100 km s-1 and baryon density ~ 10-25 kg/m3 is enough to generate the observed warps and this mechanism offers quite a plausible explanation. First, because this order of accretion rate is inferred from other processes observed in the Galaxy, notably its chemical evolution. The inferred rate of infall of matter, ~ 1 M_sun/yr, to the Galactic disc that this theory predicts agrees with the quantitative predictions of this chemical evolution resolving key issues, notably the G-dwarf problem. Second, the required density of the intergalactic medium is within the range of values compatible with observation. By this mechanism, we can explain the warp phenomenon in terms of intergalactic accretion <span class="hlt">flows</span> onto the disk of the galaxy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SMaS...21d5003W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SMaS...21d5003W"><span>Vortex shedding induced energy harvesting from piezoelectric materials in heating, ventilation and <span class="hlt">air</span> conditioning <span class="hlt">flows</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weinstein, L. A.; Cacan, M. R.; So, P. M.; Wright, P. K.</p> <p>2012-04-01</p> <p>A cantilevered piezoelectric beam is excited in a heating, ventilation and <span class="hlt">air</span> conditioning (HVAC) <span class="hlt">flow</span>. This excitation is amplified by the interactions between (a) an aerodynamic fin attached at the end of the piezoelectric cantilever and (b) the vortex shedding downstream from a bluff body placed in the <span class="hlt">air</span> <span class="hlt">flow</span> ahead of the fin/cantilever assembly. The positioning of small weights along the fin enables tuning of the energy harvester to operate at resonance for <span class="hlt">flow</span> velocities from 2 to 5 m s-1, which are characteristic of HVAC ducts. In a 15 cm diameter <span class="hlt">air</span> duct, power generation of 200 μW for a <span class="hlt">flow</span> speed of 2.5 m s-1 and power generation of 3 mW for a <span class="hlt">flow</span> speed of 5 m s-1 was achieved. These power outputs are sufficient to power a wireless sensor node for HVAC monitoring systems or other sensors for smart building technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1770c0104K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1770c0104K"><span>Creation of the reduced-density region by a pulsing optical discharge in the supersonic <span class="hlt">air</span> <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kiseleva, T. A.; Orishich, A. M.; Chirkashenko, V. F.; Yakovlev, V. I.</p> <p>2016-10-01</p> <p>As a result of optical and pneumometric measurements is defined the <span class="hlt">flow</span> shock wave structure that is formed by the optical breakdown, <span class="hlt">due</span> to focused repetitively pulsed CO2 laser radiation when entering perpendicular to a supersonic (M = 1.36, 1.9) <span class="hlt">air</span> <span class="hlt">flow</span> direction. The dynamics of the bow shock formation in front of the energy input area is shown, depending on the frequency of energy impulse sequence. A <span class="hlt">flow</span> structure is defined in the thermal wake behind pulsing laser plasma as well as wake's length with low thermal heterogeneity. A three-dimensional configuration of the energy area is defined in accordance with pneumometric and optical measuring results. It is shown that Pitot pressure decreases in thermal wake at a substantially constant static pressure, averaged <span class="hlt">flow</span> parameters weakly depend on the energy impulse's frequency in range of 45-150 kHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JThSc..19..136L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JThSc..19..136L"><span>Mixing characteristics of pulsed <span class="hlt">air</span>-assist liquid jet into an internal subsonic cross-<span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Inchul; Kang, Youngsu; Koo, Jaye</p> <p>2010-04-01</p> <p>Penetration depth, spray dispersion angle, droplet sizes in breakup processes and atomization processes are very important parameters in combustor of <span class="hlt">air</span>-breathing engine. These processes will enhance <span class="hlt">air</span>/fuel mixing inside the combustor. Experimental results from the pulsed <span class="hlt">air</span>-assist liquid jet injected into a cross-<span class="hlt">flow</span> are investigated. And experiments were conducted to a range of cross-<span class="hlt">flow</span> velocities from 42˜136 m/s. <span class="hlt">Air</span> is injected with 0˜300kPa, with <span class="hlt">air</span>-assist pulsation frequency of 0˜20Hz. Pulsation frequency was modulated by solenoid valve. Phase Doppler Particle Analyzer(PDPA) was utilized to quantitatively measuring droplet characteristics. High-speed CCD camera was used to obtain injected spray structure. Pulsed <span class="hlt">air</span>-assist liquid jet will offer rapid mixing and good liquid jet penetration. <span class="hlt">Air</span>-assist makes a very fine droplet which generated mist-like spray. Pulsed <span class="hlt">air</span>-assist liquid jet will introduce additional supplementary turbulent mixing and control of penetration depth into a cross-<span class="hlt">flow</span> field. The results show that pulsation frequency has an effect on penetration, transverse velocities and droplet sizes. The experimental data generated in these studies are used for a development of active control strategies to optimize the liquid jet penetration in subsonic cross-<span class="hlt">flow</span> conditions and predict combustion low frequency instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/663549','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/663549"><span>COMIS -- an international multizone <span class="hlt">air-flow</span> and contaminant transport model</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Feustel, H.E.</p> <p>1998-08-01</p> <p>A number of interzonal models have been developed to calculate <span class="hlt">air</span> <span class="hlt">flows</span> and pollutant transport mechanisms in both single and multizone buildings. A recent development in multizone <span class="hlt">air-flow</span> modeling, the COMIS model, has a number of capabilities that go beyond previous models, much as COMIS can be used as either a stand-alone <span class="hlt">air-flow</span> model with input and output features or as an infiltration module for thermal building simulation programs. COMIS was designed during a 12 month workshop at Lawrence Berkeley National Laboratory (LBNL) in 1988-89. In 1990, the Executive Committee of the International Energy Agency`s Energy Conservation in Buildings and Community Systems program created a working group on multizone <span class="hlt">air-flow</span> modeling, which continued work on COMIS. The group`s objectives were to study physical phenomena causing <span class="hlt">air</span> <span class="hlt">flow</span> and pollutant (e.g., moisture) transport in multizone buildings, develop numerical modules to be integrated in the previously designed multizone <span class="hlt">air</span> <span class="hlt">flow</span> modeling system, and evaluate the computer code. The working group supported by nine nations, officially finished in late 1997 with the release of IISiBat/COMIS 3.0, which contains the documented simulation program COMIS, the user interface IISiBat, and reports describing the evaluation exercise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21361434','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21361434"><span>Measurement of the resistivity of porous materials with an alternating <span class="hlt">air-flow</span> method.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dragonetti, Raffaele; Ianniello, Carmine; Romano, Rosario A</p> <p>2011-02-01</p> <p><span class="hlt">Air-flow</span> resistivity is a main parameter governing the acoustic behavior of porous materials for sound absorption. The international standard ISO 9053 specifies two different methods to measure the <span class="hlt">air-flow</span> resistivity, namely a steady-state <span class="hlt">air-flow</span> method and an alternating <span class="hlt">air-flow</span> method. The latter is realized by the measurement of the sound pressure at 2 Hz in a small rigid volume closed partially by the test sample. This cavity is excited with a known volume-velocity sound source implemented often with a motor-driven piston oscillating with prescribed area and displacement magnitude. Measurements at 2 Hz require special instrumentation and care. The authors suggest an alternating <span class="hlt">air-flow</span> method based on the ratio of sound pressures measured at frequencies higher than 2 Hz inside two cavities coupled through a conventional loudspeaker. The basic method showed that the imaginary part of the sound pressure ratio is useful for the evaluation of the <span class="hlt">air-flow</span> resistance. Criteria are discussed about the choice of a frequency range suitable to perform simplified calculations with respect to the basic method. These criteria depend on the sample thickness, its nonacoustic parameters, and the measurement apparatus as well. The proposed measurement method was tested successfully with various types of acoustic materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21071606','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21071606"><span>Improving <span class="hlt">flow</span> and spillage characteristics of range hoods by using an inclined <span class="hlt">air</span>-curtain technique.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Rong Fung; Nian, You-Cyun; Chen, Jia-Kun; Peng, Kuan-Lin</p> <p>2011-03-01</p> <p>The current study developed a new type of range hood, which was termed an 'inclined <span class="hlt">air</span>-curtain range hood', in order to improve the <span class="hlt">flow</span> and performance of the conventionally used wall-mounted range hood. The <span class="hlt">flow</span> characteristics and oil mist spillages of <span class="hlt">air</span>-curtain and conventional range hoods under the influences of both a mannequin presence and a simulated walk-by motion were experimentally examined. The study examined <span class="hlt">flow</span> patterns by using a laser-light-sheet-assisted smoke-<span class="hlt">flow</span> visualization technique and diagnosed spillages by using the tracer gas concentration test method. A mannequin presented in front of the conventional hood induced turbulent dispersion of oil mists toward the chest and nose of the mannequin owing to the complex interaction among the suction, wake, and wall effect, while the inclined <span class="hlt">air</span>-curtain hood presented excellent hood performance by isolating the oil mists from the mannequin with an <span class="hlt">air</span> curtain and therefore could reduce spillages out into the atmosphere and the mannequin's breathing zone. Both <span class="hlt">flow</span> visualization and the tracer gas test indicated that the <span class="hlt">air</span>-curtain hood had excellent 'robustness' over the conventional hood in resisting the influence of walk-by motion. The <span class="hlt">air</span>-curtain technique could drastically improve the <span class="hlt">flow</span> characteristics and performance of the range hood by consuming less energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790010278','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790010278"><span>Thermal performance evaluation of MSFC hot <span class="hlt">air</span> collectors with various <span class="hlt">flow</span> channel depth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1979-01-01</p> <p>The test procedures used and the results obtained during the evaluation test program on the MSFC <span class="hlt">air</span> collector with <span class="hlt">flow</span> channel depth of 3 in., 2 in., and 1 in., under simulated conditions are presented. The MSFC hot <span class="hlt">air</span> collector consists of a single glass cover with a nonselective coating absorber plate and uses <span class="hlt">air</span> as the heat transfer medium. The absorber panel consists of a thin flat sheet of aluminum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/835540','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/835540"><span>Development of Interfacial Structure in a Confined <span class="hlt">Air</span>-Water Cap-Turbulent and Churn-Turbulent <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>X. Sun; S. Kim; L. Cheng; M. Ishii; S.G. Beus</p> <p>2001-10-31</p> <p>The objective of the present work is to study and model the interfacial structure development of <span class="hlt">air</span>-water two-phase <span class="hlt">flow</span> in a confined test section. Experiments of a total of 9 <span class="hlt">flow</span> conditions in a cap-turbulent and churn-turbulent <span class="hlt">flow</span> regimes are carried out in a vertical <span class="hlt">air</span>-water upward two-phase <span class="hlt">flow</span> experimental loop with a test section of 20-cm in width and 1-cm in gap. The miniaturized four-sensor conductivity probes are used to measure local two-phase parameters at three different elevations for each <span class="hlt">flow</span> condition. The bubbles captured by the probes are categorized into two groups in view of the two-group interfacial area transport equation, i.e., spherical/distorted bubbles as Group 1 and cap/churn-turbulent bubbles as Group 2. The acquired parameters are time-averaged local void fraction, interfacial velocity, bubble number frequency, interfacial area concentration, and bubble Sauter mean diameter for both groups of bubbles. Also, the line-averaged and area-averaged data are presented and discussed. The comparisons of these parameters at different elevations demonstrate the development of interfacial structure along the <span class="hlt">flow</span> direction <span class="hlt">due</span> to bubble interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21072826','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21072826"><span>Development of Interfacial Structure in a Confined <span class="hlt">Air</span>-Water Cap-Turbulent and Churn-Turbulent <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xiaodong Sun; Seungjin Kim; Ling Cheng; Mamoru Ishii; Beus, Stephen G.</p> <p>2002-07-01</p> <p>The objective of the present work is to study and model the interfacial structure development of <span class="hlt">air</span>-water two-phase <span class="hlt">flow</span> in a confined test section. Experiments of a total of 9 <span class="hlt">flow</span> conditions in cap-turbulent and churn-turbulent <span class="hlt">flow</span> regimes are carried out in a vertical <span class="hlt">air</span>-water upward two-phase <span class="hlt">flow</span> experimental loop with a test section of 200-mm in width and 10-mm in gap. Miniaturized four-sensor conductivity probes are used to measure local two-phase parameters at three different elevations for each <span class="hlt">flow</span> condition. The bubbles captured by the probes are categorized into two groups in view of the two-group interfacial area transport equation, i.e., spherical/distorted bubbles as Group 1 and cap/churn-turbulent bubbles as Group 2. The acquired parameters are time-averaged local void fraction, interfacial velocity, bubble number frequency, interfacial area concentration, and bubble Sauter mean diameter for both groups of bubbles. Also, the line-averaged and area-averaged data are presented and discussed. The comparisons of these parameters at different elevations demonstrate the development of interfacial structure along the <span class="hlt">flow</span> direction <span class="hlt">due</span> to bubble interactions. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730019412','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730019412"><span>Apparatus and method for generating large mass <span class="hlt">flow</span> of high temperature <span class="hlt">air</span> at hypersonic speeds</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sabol, A. P.; Stewart, R. B. (Inventor)</p> <p>1973-01-01</p> <p>High temperature, high mass <span class="hlt">air</span> <span class="hlt">flow</span> and a high Reynolds number test <span class="hlt">air</span> <span class="hlt">flow</span> in the Mach number 8-10 regime of adequate test <span class="hlt">flow</span> duration is attained by pressurizing a ceramic-lined storage tank with <span class="hlt">air</span> to a pressure of about 100 to 200 atmospheres. The <span class="hlt">air</span> is heated to temperatures of 7,000 to 8,000 R prior to introduction into the tank by passing the <span class="hlt">air</span> over an electric arc heater means. The <span class="hlt">air</span> cools to 5,500 to 6,000 R while in the tank. A decomposable gas such as nitrous oxide or a combustible gas such as propane is injected into the tank after pressurization and the heated pressurized <span class="hlt">air</span> in the tank is rapidly released through a Mach number 8-10 nozzle. The injected gas medium upon contact with the heated pressurized <span class="hlt">air</span> effects an exothermic reaction which maintains the pressure and temperature of the pressurized <span class="hlt">air</span> during the rapid release.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/486084','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/486084"><span>Computational fluid dynamics simulation of the <span class="hlt">air</span>/suppressant <span class="hlt">flow</span> in an uncluttered F18 engine nacelle</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lopez, A.R.; Gritzo, L.A.; Hassan, B.</p> <p>1997-06-01</p> <p>For the purposes of designing improved Halon-alternative fire suppression strategies for aircraft applications, Computational Fluid Dynamics (CFD) simulations of the <span class="hlt">air</span> <span class="hlt">flow</span>, suppressant transport, and <span class="hlt">air</span>-suppressant mixing within an uncluttered F18 engine nacelle were performed. The release of inert gases from a Solid Propellant Gas Generator (SPGG) was analyzed at two different injection locations in order to understand the effect of injection position on the <span class="hlt">flow</span> patterns and the mixing of <span class="hlt">air</span> and suppression agent. An uncluttered engine nacelle was simulated to provide insight into the global <span class="hlt">flow</span> features as well as to promote comparisons with previous nacelle fire tests and recent water tunnel tests which included little or no clutter. Oxygen concentration levels, fuel/<span class="hlt">air</span> residence times that would exist if a small fuel leak were present, velocity contours, and streamline patterns are presented inside the engine nacelle. The numerical results show the influence of the gent release location on regions of potential flame extinction <span class="hlt">due</span> to oxygen inerting and high flame strain. The occurrence of inflow through the exhaust ducts on the aft end of the nacelle is also predicted. As expected, the predicted oxygen concentration levels were consistently higher than the measured levels since a fire was not modeled in this analysis. Despite differences in the conditions of these simulations and the experiments, good agreement was obtained between the CFD predictions and the experimental measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H31C1422K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H31C1422K"><span>Verification and Validation of Numerical Models for <span class="hlt">Air</span>/Water <span class="hlt">Flow</span> on Coastal and Navigation Fluid-Structure Interaction Applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kees, C. E.; Farthing, M.; Dimakopoulos, A.; DeLataillade, T.</p> <p>2015-12-01</p> <p>Performance analysis and optimization of coastal and navigation structures is becoming feasible <span class="hlt">due</span> to recent improvements in numerical methods for multiphase <span class="hlt">flows</span> and the steady increase in capacity and availability of high performance computing resources. Now that the concept of fully three-dimensional <span class="hlt">air</span>/water <span class="hlt">flow</span> modelling for real world engineering analysis is achieving acceptance by the wider engineering community, it is critical to expand careful comparative studies on verification,validation, benchmarking, and uncertainty quantification for the variety of competing numerical methods that are continuing to evolve. Furthermore, uncertainty still remains about the relevance of secondary processes such as surface tension, <span class="hlt">air</span> compressibility, <span class="hlt">air</span> entrainment, and solid phase (structure) modelling so that questions about continuum mechanical theory and mathematical analysis of multiphase <span class="hlt">flow</span> are still required. Two of the most popular and practical numerical approaches for large-scale engineering analysis are the Volume-Of-Fluid (VOF) and Level Set (LS) approaches. In this work we will present a publically available verification and validation test set for <span class="hlt">air</span>-water-structure interaction problems as well as computational and physical model results including a hybrid VOF-LS method, traditional VOF methods, and Smoothed Particle Hydrodynamics (SPH) results. The test set repository and test problem formats will also be presented in order to facilitate future comparative studies and reproduction of scientific results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.4899..165Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.4899..165Y"><span>Analysis of tropospheric scintillation <span class="hlt">due</span> to clear-<span class="hlt">air</span> and meteorological elements on slant microwave links</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Ruike; Wu, ZhenSen; Li, Yingle</p> <p>2003-04-01</p> <p>Analysis of log-amplitude scintillation <span class="hlt">due</span> to troposphere clear-<span class="hlt">air</span> turbulent and meteorological parameters variation is shown at microwaves (MW) on slant paths, based on ITU-R turbulence atmosphere structure parameter, temperature and relative humidity along vertical path. Comparisons of Karasawa model based on the data obtained from a low-elevation microwave propagation experiment and ITU-R Recommendation model prediction results with evaluation results are shown and discussed. The results show that although the relative humidity effected on optical refractive index of a cell is not principally element at optical wave band, at microwave and millimeter-wave band, the relative humidity and temperature is the major factor impacted on log-amplitude scintillation. Hence, the variations of temperature and relative humidity with height, which can be obtained by experiment (or test) and weather observation method is important for low-elevation satellite communication and microwave remote sensing. A atmosphere structure constant Cn2 model, which varies with height, is presented based on ITU-R and Karasawa amplitude scintillation model, existing ITU-R Cn2 model for optical and meteorologic measured relative humidity and temperature data, at 10~30GHz. In this Cn2 model it is considered that relative humidity and temperature varies with height. The log-amplitude scintillation deviation calculated in terms of the Cn2 model based on humidity and temperature vertical profile compare with values predicted by means of ITU-R and Ortgies model applied to Italsat channels. It is emerged that the calculation results based on the Cn2 model agree almost with prediction results by ITU-R and Ortgies model at 10~30GHz and there is an advantage that relative humidity and temperature varied with height has be considered in the Cn2 model. Therefore, it is shown that the Cn2 model is usable and is more practical.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21160668','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21160668"><span>Recurrent tense pneumoperitoneum <span class="hlt">due</span> to <span class="hlt">air</span> influx via abdominal wall stoma of a PEG tube.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vijayakrishnan, Rajakrishnan; Adhikari, Deep; Anand, Curuchi P</p> <p>2010-07-28</p> <p>A 70 years old male on ventilatory and circulatory support for sepsis and non ST segment elevation myocardial infarction developed abdominal distension 14 d after placement of a percutaneous endoscopic gastrostomy tube for enteral feeding. Radiography revealed free <span class="hlt">air</span> in the abdomen and gastrograffin (G) study showed no extravasation into the peritoneum. The G tube was successfully repositioned with mechanical release of <span class="hlt">air</span>. Imaging showed complete elimination of free <span class="hlt">air</span> but the patient had a recurrence of pneumoperitoneum. Mechanical release of <span class="hlt">air</span> with sealing of the abdominal wound was performed. Later, the patient was restarted on tube feeding with no complications. This case demonstrates a late complication of pneumoperitoneum with <span class="hlt">air</span> leakage from the abdominal wall stoma.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5551G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5551G"><span>Experimental response of Salix cuttings to different <span class="hlt">flow</span> regimes <span class="hlt">due</span> to human activities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorla, Lorenzo; Signarbieux, Constant; Turberg, Pascal; Buttler, Alexandre; Perona, Paolo</p> <p>2014-05-01</p> <p>Hydropower production and other human activities change the natural <span class="hlt">flow</span> regime of rivers, in turn impacting the riparian environment. The main challenge in order to define eco-sustainable <span class="hlt">flows</span> is to quantify the effects in terms of geomorphology and ecosystem adaptation. We present 2-years controlled experiments to investigate riparian vegetation (Salix Viminalis) response to forced water table changing dynamics, from one water regime to another, in a temperate region (Switzerland). Three synthetic <span class="hlt">flow</span> regimes have been simulated and applied to three batteries of Salix cuttings growing outdoor within plastic pots, each about 1 meter tall. In 2012 one treatment simulated a minimal <span class="hlt">flow</span> policy for small run-of-river hydropower plants, which drastically impacts the low and the medium-low components of the hydrograph, but not the extremes. In 2013 we confirmed and completed some of 2012 results, by reproducing typical hydropeaking effects <span class="hlt">due</span> to dam management and focusing on daily water table variations and offsets. For both the seasons, after an initial period where all pots undergone the same oscillations in order to uniform the plants initial conditions, the experiment started, and the water dynamic was changed. Cuttings transitory response dynamics has been quantified by continuous sap <span class="hlt">flow</span> and water potential measurements, and by regularly collecting growth parameters, as well as leaves photosynthesis, fluorescence, and pictures of each plant. At the end of the experiment, all cuttings were carefully removed and the both above and below ground biomass analyzed in detail. Particularly, the 3D root structure was obtained by High Resolution Computer Tomography. Our analyses revealed a clear dependence between roots distribution and water regime reflecting the need for adaptation, in agreement with field observations of Pasquale et al. (2012). In particular, an initial strong difference in terms of stress and growth performances was then followed by a later</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.822a2032T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.822a2032T"><span>Investigation of <span class="hlt">flow</span> inside pulverized coal (PC) pipes against coal particle size and <span class="hlt">air</span> <span class="hlt">flow</span> rate for a utility boiler</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thrangaraju, Savithry K.; Munisamy, Kannan M.; Apparao, Rucgnes</p> <p>2017-04-01</p> <p>This study mainly focuses on investigation on effect coal particle size on <span class="hlt">flow</span> inside pulverized coal pipes for a utility boiler. The <span class="hlt">flow</span> that is analyzed here will be the wall shear stress. The objective of the study is to determine the effect of coal particle size and effect of <span class="hlt">air</span> <span class="hlt">flow</span> rate on the wall shear stress of pulverized coal pipes. The individual wall shear stress which is computed as area weighted average of the pulverized coal pipes that is studied is compared and analyzed. There are total of 28 pulverized coal pipes in the power plant that is chosen as case study. The study is divided into two parts mainly the effect of coal particle size on the wall shear stress and the other is effect of <span class="hlt">air</span> <span class="hlt">flow</span> rate on the wall shear stress. In both configurations the wall shear stress is computed as area weighted average. Prior to simulation the file that is used to study the wall shear stress is modified using Gambit to improve results. The individual wall shear stress of all pipes coming out of a particular mill is observed after contours are developed using CFD tool like Ansys fluent. Parameters like coal <span class="hlt">flow</span> rate and coal velocity are set in the simulation and results are generated Based on contours and developed graph from the simulation, the effect of both configuration is studied and the range of particle size and range of <span class="hlt">air</span> <span class="hlt">flow</span> rate which is suitable for the optimum operation of boiler is suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740011532','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740011532"><span>Pressure-loss and <span class="hlt">flow</span> coefficients inside a chordwise-finned, impingement, convection, and film <span class="hlt">air</span>-cooled turbine vane</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hippensteele, S. A.</p> <p>1974-01-01</p> <p>Total-pressure-loss coefficients, <span class="hlt">flow</span> discharge coefficients, and friction factors were determined experimentally for the various area and geometry changes and <span class="hlt">flow</span> passages within an <span class="hlt">air</span>-cooled turbine vane. The results are compared with those of others obtained on similar configurations, both actual and large models, of vane passages. The supply and exit <span class="hlt">air</span> pressures were controlled and varied. The investigation was conducted with essentially ambient-temperature <span class="hlt">air</span> and without external <span class="hlt">flow</span> of <span class="hlt">air</span> over the vane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28499157','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28499157"><span>Identify temporal trend of <span class="hlt">air</span> temperature and its impact on forest stream <span class="hlt">flow</span> in Lower Mississippi River Alluvial Valley using wavelet analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ouyang, Ying; Parajuli, Prem B; Li, Yide; Leininger, Theodor D; Feng, Gary</p> <p>2017-08-01</p> <p>Characterization of stream <span class="hlt">flow</span> is essential to water resource management, water supply planning, environmental protection, and ecological restoration; while <span class="hlt">air</span> temperature variation <span class="hlt">due</span> to climate change can exacerbate stream <span class="hlt">flow</span> and add instability to the <span class="hlt">flow</span>. In this study, the wavelet analysis technique was employed to identify temporal trend of <span class="hlt">air</span> temperature and its impact upon forest stream <span class="hlt">flows</span> in Lower Mississippi River Alluvial Valley (LMRAV). Four surface water monitoring stations, which locate near the headwater areas with very few land use disturbances and the long-term data records (60-90 years) in the LMRAV, were selected to obtain stream discharge and <span class="hlt">air</span> temperature data. The wavelet analysis showed that <span class="hlt">air</span> temperature had an increasing temporal trend around its mean value during the past several decades in the LMRAV, whereas stream <span class="hlt">flow</span> had a decreasing temporal trend around its average value at the same time period in the same region. Results of this study demonstrated that the climate in the LMRAV did get warmer as time elapsed and the streams were drier as a result of warmer <span class="hlt">air</span> temperature. This study further revealed that the best way to estimate the temporal trends of <span class="hlt">air</span> temperature and stream <span class="hlt">flow</span> was to perform the wavelet transformation around their mean values. Published by Elsevier Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title42-vol1/pdf/CFR-2010-title42-vol1-sec84-148.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title42-vol1/pdf/CFR-2010-title42-vol1-sec84-148.pdf"><span>42 CFR 84.148 - Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class; minimum requirements.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 42 Public Health 1 2010-10-01 2010-10-01 false Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class; minimum requirements. 84.148 Section 84.148 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... <span class="hlt">flow</span> class; minimum requirements. (a) Respirators tested under this section shall be approved only...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title42-vol1/pdf/CFR-2011-title42-vol1-sec84-148.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title42-vol1/pdf/CFR-2011-title42-vol1-sec84-148.pdf"><span>42 CFR 84.148 - Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class; minimum requirements.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 42 Public Health 1 2011-10-01 2011-10-01 false Type C supplied-<span class="hlt">air</span> respirator, continuous <span class="hlt">flow</span> class; minimum requirements. 84.148 Section 84.148 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF... <span class="hlt">flow</span> class; minimum requirements. (a) Respirators tested under this section shall be approved only when...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA477828','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA477828"><span>Origin and Control of the <span class="hlt">Flow</span> Structure on Unmanned Combat <span class="hlt">Air</span> Vehicle</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2007-12-01</p> <p>Prescrtbed by ANSI Ski Z3S.18 AFOSR Final Repot 013108 ORIGIN AND CONTROL OF THE <span class="hlt">FLOW</span> STRUCTURE ON UNMANNED COMBAT <span class="hlt">AIR</span> VEHICLES AFOSR GRANT #FA9550-05...1991) described low-dimensional models for <span class="hlt">flows</span> past a grooved channel and circular cylinders. By employing a Galerkin method, a governing partial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...625900L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...625900L"><span>The burden of COPD mortality <span class="hlt">due</span> to ambient <span class="hlt">air</span> pollution in Guangzhou, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Li; Yang, Jun; Song, Yun-Feng; Chen, Ping-Yan; Ou, Chun-Quan</p> <p>2016-05-01</p> <p>Few studies have investigated the chronic obstructive pulmonary disease (COPD) mortality fraction attributable to <span class="hlt">air</span> pollution and modification by individual characteristics of <span class="hlt">air</span> pollution effects. We applied distributed lag non-linear models to assess the associations between <span class="hlt">air</span> pollution and COPD mortality in 2007–2011 in Guangzhou, China, and the total COPD mortality fraction attributable to <span class="hlt">air</span> pollution was calculated as well. We found that an increase of 10 μg/m3 in particulate matter with an aerodynamic diameter of 10 μm or less (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2) was associated with a 1.58% (95% confidence interval (CI): 0.12–3.06%), 3.45% (95% CI: 1.30–5.66%) and 2.35% (95% CI: 0.42–4.32%) increase of COPD mortality over a lag of 0–15 days, respectively. Greater <span class="hlt">air</span> pollution effects were observed in the elderly, males and residents with low educational attainment. The results showed 10.91% (95% CI: 1.02–9.58%), 12.71% (95% CI: 5.03–19.85%) and 13.38% (95% CI: 2.67–22.84%) COPD mortality was attributable to current PM10, SO2 and NO2 exposure, respectively. In conclusion, the associations between <span class="hlt">air</span> pollution and COPD mortality differed by individual characteristics. There were remarkable COPD mortality burdens attributable to <span class="hlt">air</span> pollution in Guangzhou.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27195597','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27195597"><span>The burden of COPD mortality <span class="hlt">due</span> to ambient <span class="hlt">air</span> pollution in Guangzhou, China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Li; Yang, Jun; Song, Yun-Feng; Chen, Ping-Yan; Ou, Chun-Quan</p> <p>2016-05-19</p> <p>Few studies have investigated the chronic obstructive pulmonary disease (COPD) mortality fraction attributable to <span class="hlt">air</span> pollution and modification by individual characteristics of <span class="hlt">air</span> pollution effects. We applied distributed lag non-linear models to assess the associations between <span class="hlt">air</span> pollution and COPD mortality in 2007-2011 in Guangzhou, China, and the total COPD mortality fraction attributable to <span class="hlt">air</span> pollution was calculated as well. We found that an increase of 10 μg/m(3) in particulate matter with an aerodynamic diameter of 10 μm or less (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2) was associated with a 1.58% (95% confidence interval (CI): 0.12-3.06%), 3.45% (95% CI: 1.30-5.66%) and 2.35% (95% CI: 0.42-4.32%) increase of COPD mortality over a lag of 0-15 days, respectively. Greater <span class="hlt">air</span> pollution effects were observed in the elderly, males and residents with low educational attainment. The results showed 10.91% (95% CI: 1.02-9.58%), 12.71% (95% CI: 5.03-19.85%) and 13.38% (95% CI: 2.67-22.84%) COPD mortality was attributable to current PM10, SO2 and NO2 exposure, respectively. In conclusion, the associations between <span class="hlt">air</span> pollution and COPD mortality differed by individual characteristics. There were remarkable COPD mortality burdens attributable to <span class="hlt">air</span> pollution in Guangzhou.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.822a2022I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.822a2022I"><span><span class="hlt">Air</span> <span class="hlt">flow</span> optimization for energy efficient blower of biosafety cabinet class II A2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ibrahim, M. D.; Mohtar, M. Z.; Alias, A. A.; Wong, L. K.; Yunos, Y. S.; Rahman, M. R. A.; Zulkharnain, A.; Tan, C. S.; Thayan, R.</p> <p>2017-04-01</p> <p>An energy efficient Biosafety Cabinet (BSC) has become a big challenge for manufacturers to develop BSC with the highest level of protection. The objective of research is to increase <span class="hlt">air</span> <span class="hlt">flow</span> velocity discharge from centrifugal blower. An aerodynamic duct shape inspired by the shape of Peregrine Falcon’s wing during diving flight is added to the end of the centrifugal blower. Investigation of <span class="hlt">air</span> movement is determined by computational fluid dynamics (CFD) simulation. The results showed that <span class="hlt">air</span> velocity can be increased by double compared to typical manufactured BSC and no <span class="hlt">air</span> recirculation. As conclusion, a novel design of aerodynamic duct shape successfully developed and proved that <span class="hlt">air</span> velocity can be increase naturally with same impeller speed. It can contribute in increasing energy efficiency of the centrifugal blower. It is vital to BSC manufacturer and can be apply to Heating, <span class="hlt">Air</span> Ventilation and <span class="hlt">Air</span> Conditioning (HVAC) industries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/106986','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/106986"><span>A criterion for the onset of slugging in horizontal stratified <span class="hlt">air</span>-water countercurrent <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chun, Moon-Hyun; Lee, Byung-Ryung; Kim, Yang-Seok</p> <p>1995-09-01</p> <p>This paper presents an experimental and theoretical investigation of wave height and transition criterion from wavy to slug <span class="hlt">flow</span> in horizontal <span class="hlt">air</span>-water countercurrent stratified <span class="hlt">flow</span> conditions. A theoretical formula for the wave height in a stratified wavy <span class="hlt">flow</span> regime has been developed using the concept of total energy balance over a wave crest to consider the shear stress acting on the interface of two fluids. From the limiting condition of the formula for the wave height, a necessary criterion for transition from a stratified wavy <span class="hlt">flow</span> to a slug <span class="hlt">flow</span> has been derived. A series of experiments have been conducted changing the non-dimensional water depth and the <span class="hlt">flow</span> rates of <span class="hlt">air</span> in a horizontal pipe and a duct. Comparisons between the measured data and the predictions of the present theory show that the agreement is within {plus_minus}8%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18507169','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18507169"><span>[The health status of children from industrial towns <span class="hlt">due</span> ambient <span class="hlt">air</span> pollution].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Meĭbaliev, M T</p> <p>2008-01-01</p> <p>The author's observations suggest that hygienic monitoring in an industrial city should be made in two areas: 1) ambient <span class="hlt">air</span> quality and 2) human health. Ambient <span class="hlt">air</span> quality should be monitored in each town in accordance with an individual program, by taking into account the volume and nature of hazardous substances from the stationary stations, as well as weather conditions, the planning system of residential areas, and the layout of an industrial zone. Monitoring of the population's health in the industrial town should be adapted to the forms and conditions of ambient <span class="hlt">air</span> quality monitoring in order to reveal environmental pollution-induced changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26469262','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26469262"><span>[<span class="hlt">Air</span> Bubble in the Left Ventricle <span class="hlt">due</span> to Computed Tomography Guided Lung Needle Biopsy].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Matsuda, Eisuke; Yoshida, Kumiko; Yoshiyama, Koichi; Hayashi, Tatsuro; Tanaka, Toshiki; Tao, Hiroyuki; Okabe, Kazunori</p> <p>2015-11-01</p> <p>Computed tomography (CT) guided lung biopsy is a useful examination in diagnosing pulmonary diseases, but the complications such as pneumothorax or pulmonary hemorrhage can not be ignored. Among them, <span class="hlt">air</span> embolization is a severe complication, although it is infrequently encountered. Forty two-year-old man admitted to our department for the examination of left lung tumor. CT guided lung biopsy was performed. After examination, the patient showed disturbance in cardiac function, which recovered in several minutes. Chest CT revealed <span class="hlt">air</span> bubble in the left ventricle. After 2-hours head down position followed by bed rest, <span class="hlt">air</span> bubble is confirmed to be dissappeared by CT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH51D1931E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH51D1931E"><span>An experimental study of geyser-like <span class="hlt">flows</span> induced by a pressurized <span class="hlt">air</span> pocket</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elayeb, I. S.; Leon, A.; Choi, Y.; Alnahit, A. O.</p> <p>2015-12-01</p> <p>Previous studies argues that the entrapment of pressurized <span class="hlt">air</span> pockets within combined sewer systems can produce geyser <span class="hlt">flows</span>, which is an oscillating jetting of a mixture of gas-liquid <span class="hlt">flows</span>. To verify that pressurized <span class="hlt">air</span> pockets can effectively produce geysers, laboratory experiments were conducted. However, past experiments were conducted in relatively small-scale apparatus (i.e. maximum φ2" vertical shaft). This study conducted a set of experiments in a larger apparatus. The experimental setup consists of an upstream head tank, a downstream head tank, a horizontal pipe (46.5ft long, φ6") and a vertical pipe (10ft long, φ6"). The initial condition for the experiments is constant <span class="hlt">flow</span> discharge through the horizontal pipe. The experiments are initiated by injecting an <span class="hlt">air</span> pocket with pre-determined volume and pressure at the upstream end of the horizontal pipe. The <span class="hlt">air</span> pocket propagates through the horizontal pipe until it arrives to the vertical shaft, where it is released producing a geyser-like <span class="hlt">flow</span>. Three <span class="hlt">flow</span> rates in the horizontal pipe and three injected <span class="hlt">air</span> pressures were tested. The variables measured were pressure at two locations in the horizontal pipe and two locations in the vertical pipe. High resolution videos at two regions in the vertical shaft were also recorded. To gain further insights in the physics of <span class="hlt">air</span>-water interaction, the laboratory experiments were complemented with numerical simulations conducted using a commercial 3D CFD model, previously validated with experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA442653','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA442653"><span><span class="hlt">Air</span> Ejector Pumping Enhancement Through Pulsing Primary <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2005-12-01</p> <p>CFD ) analysis show that pulsing the primary jet <span class="hlt">flow</span>, an active metho of <span class="hlt">flow</span> control, improved ejector performance. The physics of this improvement...without an entrance shape was found to be still reasonably efficient. Both experiments and Computer Fluid Dynamics( CFD ) analysis show that pulsing the...other shapes. A tube without an entrance shape was found to be still reasonably efficient. Both experiments and Computer Fluid Dynamics( CFD ) analysis</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050214769','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050214769"><span>Thin-Film <span class="hlt">Air-Mass-Flow</span> Sensor of Improved Design Developed</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fralick, Gustave C.; Wrbanek, John D.; Hwang, Danny P.</p> <p>2003-01-01</p> <p>Researchers at the NASA Glenn Research Center have developed a new <span class="hlt">air-mass-flow</span> sensor to solve the problems of existing mass <span class="hlt">flow</span> sensor designs. NASA's design consists of thin-film resistors in a Wheatstone bridge arrangement. The resistors are fabricated on a thin, constant-thickness airfoil to minimize disturbance to the airflow being measured. The following photograph shows one of NASA s prototype sensors. In comparison to other <span class="hlt">air-mass-flow</span> sensor designs, NASA s thin-film sensor is much more robust than hot wires, causes less airflow disturbance than pitot tubes, is more accurate than vane anemometers, and is much simpler to operate than thermocouple rakes. NASA s thin-film <span class="hlt">air-mass-flow</span> sensor works by converting the temperature difference seen at each leg of the thin-film Wheatstone bridge into a mass-<span class="hlt">flow</span> rate. The following figure shows a schematic of this sensor with <span class="hlt">air</span> <span class="hlt">flowing</span> around it. The sensor operates as follows: current is applied to the bridge, which increases its temperature. If there is no <span class="hlt">flow</span>, all the arms are heated equally, the bridge remains in balance, and there is no signal. If there is <span class="hlt">flow</span>, the <span class="hlt">air</span> passing over the upstream legs of the bridge reduces the temperature of the upstream legs and that leads to reduced electrical resistance for those legs. After the <span class="hlt">air</span> has picked up heat from the upstream legs, it continues and passes over the downstream legs of the bridge. The heated <span class="hlt">air</span> raises the temperature of these legs, increasing their electrical resistance. The resistance difference between the upstream and downstream legs unbalances the bridge, causing a voltage difference that can be amplified and calibrated to the airflow rate. Separate sensors mounted on the airfoil measure the temperature of the airflow, which is used to complete the calculation for the mass of <span class="hlt">air</span> passing by the sensor. A current application for <span class="hlt">air-mass-flow</span> sensors is as part of the intake system for an internal combustion engine. A mass-<span class="hlt">flow</span> sensor is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ThCFD..30..485B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ThCFD..30..485B"><span>Bifurcations of a creeping <span class="hlt">air</span>-water <span class="hlt">flow</span> in a conical container</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balci, Adnan; Brøns, Morten; Herrada, Miguel A.; Shtern, Vladimir N.</p> <p>2016-10-01</p> <p>This numerical study describes the eddy emergence and transformations in a slow steady axisymmetric <span class="hlt">air</span>-water <span class="hlt">flow</span>, driven by a rotating top disk in a vertical conical container. As water height Hw and cone half-angle β vary, numerous <span class="hlt">flow</span> metamorphoses occur. They are investigated for β =30°, 45°, and 60°. For small Hw, the <span class="hlt">air</span> <span class="hlt">flow</span> is multi-cellular with clockwise meridional circulation near the disk. The <span class="hlt">air</span> <span class="hlt">flow</span> becomes one cellular as Hw exceeds a threshold depending on β . For all β , the water <span class="hlt">flow</span> has an unbounded number of eddies whose size and strength diminish as the cone apex is approached. As the water level becomes close to the disk, the outmost water eddy with clockwise meridional circulation expands, reaches the interface, and induces a thin layer with anticlockwise circulation in the <span class="hlt">air</span>. Then this layer expands and occupies the entire <span class="hlt">air</span> domain. The physical reasons for the <span class="hlt">flow</span> transformations are provided. The results are of fundamental interest and can be relevant for aerial bioreactors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SolED...6.1625W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SolED...6.1625W"><span>Analogue experiments of salt <span class="hlt">flow</span> and pillow growth <span class="hlt">due</span> basement faulting and differential loading</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Warsitzka, M.; Kley, J.; Kukowski, N.</p> <p>2014-07-01</p> <p>Basement faulting is widely acknowledged as a potential trigger for salt <span class="hlt">flow</span> and the growth of salt structures in salt-bearing extensional basins. In this study, dynamically scaled analogue experiments were designed to examine the evolution of salt pillows and the kinematics of salt <span class="hlt">flow</span> <span class="hlt">due</span> to a short pulse of basement faulting and a long-lasting phase of successive sedimentation. Experiments performed in the framework of this study consist of viscous silicone putty to simulate ductile rock salt, and a PVC-beads-quartz sand mixture representing a brittle supra-salt layer. In order to derive 2-D incremental displacement and strain patterns, the analogue experiments were monitored by an optical image correlation system (Particle Imaging Velocimetry). By varying layer thicknesses and extension rates, the influence of these parameters on the kinematics of salt <span class="hlt">flow</span> were tested. Model results reveal that significant strain is triggered in the viscous layer by minor basement faulting. During basement extension downward <span class="hlt">flow</span> occurs in the viscous layer above the basement fault tip. In contrast, upward <span class="hlt">flow</span> takes place during post-extensional sedimentation. Lateral redistribution of the viscous material during post-extensional sedimentation is associated with subsidence above the footwall block and uplift adjacent to the basement faults leading to the formation of pillow structures (primary pillows). Decoupled cover faulting and the subsidence of peripheral sinks adjacent to the primary pillow causes the formation of additional pillow structures at large distance from the basement fault (secondary pillows). Experimental results demonstrate that the development of salt pillows can be triggered by basement extension, but requires a phase of tectonic quiescence. The potential for pillow growth and the displacement rate in the viscous layer increase with increasing thickness of the viscous layer and increasing extension rate, but decrease with increasing thickness of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDA32007T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDA32007T"><span>Effect of Marangoni <span class="hlt">Flows</span> on the Shape of Thin Sessile Droplets Evaporating into <span class="hlt">Air</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsoumpas, Yannis; Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre</p> <p>2015-11-01</p> <p>With the help of Mach-Zehnder interferometry, we study the (largely) axisymmetric shapes of freely receding evaporating sessile droplets of various HFE liquids. The droplets evaporate into ambient <span class="hlt">air</span> and, although the liquids are perfectly wetting, possess small finite contact angles reckoned to be evaporation-induced. The experimentally determined droplet profiles are shown here to deviate, under some conditions, from the classical macroscopic static profile of a sessile droplet, as this is determined by gravity and capillarity. These deviations are attributed to a Marangoni <span class="hlt">flow</span>, <span class="hlt">due</span> to evaporation-induced thermal gradients along the liquid-<span class="hlt">air</span> interface, and are mostly observed in conditions of high evaporation. Unlike the classical static shapes, the distorted experimental profiles exhibit an inflection point at the contact line area. When a poorly volatile liquid is considered, however, the temperature differences and the Marangoni stresses are weak, and the measurements are found to be in a good agreement with the classical static shape. Overall, the experimental findings are quantitatively confirmed by the predictions of a lubrication model accounting for the impact of the Marangoni effect on the droplet shape. Financial support of FP7 Marie Curie MULTIFLOW Network (PITNGA-2008-214919), ESA/BELSPO-PRODEX, BELSPO- μMAST (IAP 7/38) & FRS-FNRS is gratefully acknowledged.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19690000043','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19690000043"><span>Propagation of density disturbances in <span class="hlt">air</span>-water <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nassos, G. P.</p> <p>1969-01-01</p> <p>Study investigated the behavior of density waves propagating vertically in an atmospheric pressure <span class="hlt">air</span>-water system using a technique based on the correlation between density change and electric resistivity. This information is of interest to industries working with heat transfer systems and fluid power and control systems.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/52495','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/52495"><span>Cold <span class="hlt">air</span> drainage <span class="hlt">flows</span> subsidize montane valley ecosystem productivity</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Kimberly A. Novick; Andrew C. Oishi; Chelcy Ford Miniat</p> <p>2016-01-01</p> <p>In mountainous areas, cold <span class="hlt">air</span> drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro-climate...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title30-vol1/pdf/CFR-2011-title30-vol1-sec57-22213.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title30-vol1/pdf/CFR-2011-title30-vol1-sec57-22213.pdf"><span>30 CFR 57.22213 - <span class="hlt">Air</span> <span class="hlt">flow</span> (III mines).</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... nearest the face, shall be at least 6,000 cubic feet per minute, or 9,000 cubic feet per minute in longwall and continuous miner sections. The quantity of <span class="hlt">air</span> across each face at a work place shall be at...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930081225','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930081225"><span>The Nature of <span class="hlt">Air</span> <span class="hlt">Flow</span> About the Tail of an Airplane in a Spin</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scudder, N F; Miller, M P</p> <p>1932-01-01</p> <p><span class="hlt">Air</span> <span class="hlt">flow</span> about the fuselage and empennage during a high-angle-of-attack spin was made visible in flight by means of titanium-tetrachloride smoke and was photographed with a motion-picture camera. The angular relation of the direction of the smoke streamer to the airplane axes was computed and compared with the angular direction of the motion in space derived from instrument measurement of the spin of the airplane for a nearly identical mass distribution. The results showed that the fin and upper part of the rudder were almost completely surrounded by dead <span class="hlt">air</span>, which would render them inoperative; that the <span class="hlt">flow</span> around the lower portion of the rudder and the fuselage was nonturbulent; and that <span class="hlt">air</span> <span class="hlt">flowing</span> past the cockpit in a high-angle-of-attack spin could not subsequently <span class="hlt">flow</span> around control surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........10I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........10I"><span>Unscheduled load <span class="hlt">flow</span> effect <span class="hlt">due</span> to large variation in the distributed generation in a subtransmission network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Islam, Mujahidul</p> <p></p> <p>A sustainable energy delivery infrastructure implies the safe and reliable accommodation of large scale penetration of renewable sources in the power grid. In this dissertation it is assumed there will be no significant change in the power transmission and distribution structure currently in place; except in the operating strategy and regulatory policy. That is to say, with the same old structure, the path towards unveiling a high penetration of switching power converters in the power system will be challenging. Some of the dimensions of this challenge are power quality degradation, frequent false trips <span class="hlt">due</span> to power system imbalance, and losses <span class="hlt">due</span> to a large neutral current. The ultimate result is the reduced life of many power distribution components - transformers, switches and sophisticated loads. Numerous ancillary services are being developed and offered by the utility operators to mitigate these problems. These services will likely raise the system's operational cost, not only from the utility operators' end, but also reflected on the Independent System Operators and by the Regional Transmission Operators (RTO) <span class="hlt">due</span> to an unforeseen backlash of frequent variation in the load-side generation or distributed generation. The North American transmission grid is an interconnected system similar to a large electrical circuit. This circuit was not planned but designed over 100 years. The natural laws of physics govern the power <span class="hlt">flow</span> among loads and generators except where control mechanisms are installed. The control mechanism has not matured enough to withstand the high penetration of variable generators at uncontrolled distribution ends. Unlike a radial distribution system, mesh or loop networks can alleviate complex channels for real and reactive power <span class="hlt">flow</span>. Significant variation in real power injection and absorption on the distribution side can emerge as a bias signal on the routing reactive power in some physical links or channels that are not distinguishable</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JEPT...89..157D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JEPT...89..157D"><span>Use of Oriented Spray Nozzles to Set the Vapor-<span class="hlt">Air</span> <span class="hlt">Flow</span> in Rotary Motion in the Superspray Space of the Evaporative Chimney-Type Tower</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dobrego, K. V.; Davydenko, V. F.; Koznacheev, I. A.</p> <p>2016-01-01</p> <p>The present paper considers the problem of upgrading the thermal efficiency of chimney-type evaporative cooling towers <span class="hlt">due</span> to the rotary motion of the vapor-<span class="hlt">air</span> <span class="hlt">flow</span> in the superspray space. To set the vapor-<span class="hlt">air</span> <span class="hlt">flow</span> in rotary motion, we propose to use the momentum of the sprayed water. It has been shown that the existing parameters of spray nozzles permit setting up to 30% of the water <span class="hlt">flow</span> momentum in translatory motion, which is enough for changing considerably the aerodynamics of the vapor-<span class="hlt">air</span> <span class="hlt">flow</span> in the superspray space and improving the operation of the cooling tower. The optimal angle of axial inclination of the spray cone has been estimated. Recommendations are given and problems have been posed for engineering realization of the proposed technologies in a chimney-type cooling tower.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12725837','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12725837"><span>Dynamics of surfactant sorption at the <span class="hlt">air</span>/water interface: continuous-<span class="hlt">flow</span> tensiometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Svitova, T F; Wetherbee, M J; Radke, C J</p> <p>2003-05-01</p> <p>Dynamic interfacial tensiometry, gauged by axisymmetric drop shape analysis of static drops or bubbles, provides useful information on surfactant adsorption kinetics. However, the traditional pendant-drop methodology is not readily amenable to the study of desorption kinetics. Thus, the question of sorption reversibility is difficult to assess by this technique. We extend classical pendant/sessile drop dynamic tensiometry by immersing a sessile bubble in a continuously mixed optical cell. Ideal-mixed conditions are established by stirring and by constant <span class="hlt">flow</span> through the cell. Aqueous surface-active-agent solutions are either supplied to the cell (loading) or removed from the cell by flushing with water (washout), thereby allowing study of both adsorption and desorption kinetics. Well-mixed conditions and elimination of any mass transfer resistance permit direct identification of sorption kinetic barriers to and from the external aqueous phase with time constants longer than the optical-cell residence time. The monodisperse nonionic surfactant ethoxy dodecyl alcohol (C(12)E(5)), along with cationic cetyltrimethyl ammonium bromide (CTAB) in the presence of added salt, adsorbs and desorbs instantaneously at the <span class="hlt">air</span>/water interface. In these cases, the experimentally observed dynamic-tension curves follow the local-equilibrium model precisely for both loading and washout. Accordingly, these surfactants below their critical micelle concentrations (CMC) exhibit no detectable sorption-activation barriers on time scales of order a min. However, the sorption dynamics of dilute CTAB in the absence of electrolyte is markedly different from that in the presence of KBr. Here CTAB desorption occurs at local equilibrium, but the adsorption rate is kinetically limited, most likely <span class="hlt">due</span> to an electrostatic barrier arising as the charged surfactant accumulates at the interface. The commercial, polydisperse nonionic surfactant ethoxy nonylphenol (NP9) loads in good agreement with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...40a2084H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...40a2084H"><span>Temperature distribution of <span class="hlt">air</span> source heat pump barn with different <span class="hlt">air</span> <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, X.; Li, J. C.; Zhao, G. Q.</p> <p>2016-08-01</p> <p>There are two type of airflow form in tobacco barn, one is <span class="hlt">air</span> rising, the other is <span class="hlt">air</span> falling. They are different in the structure layout and working principle, which affect the tobacco barn in the distribution of temperature field and velocity distribution. In order to compare the temperature and <span class="hlt">air</span> distribution of the two, thereby obtain a tobacco barn whose temperature field and velocity distribution are more uniform. Taking the <span class="hlt">air</span> source heat pump tobacco barn as the investigated subject and establishing relevant mathematical model, the thermodynamics of the two type of curing barn was analysed and compared based on Fluent. Provide a reasonable evidence for chamber arrangement and selection of outlet for <span class="hlt">air</span> source heat pump tobacco barn.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28237472','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28237472"><span><span class="hlt">Flow</span>, stock, and impact assessment of refrigerants in the Japanese household <span class="hlt">air</span> conditioner sector.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xue, Mianqiang; Kojima, Naoya; Machimura, Takashi; Tokai, Akihiro</p> <p>2017-05-15</p> <p>Refrigerants provide society with great benefits while have the potential to cause adverse effects on the environment and human health. The present study estimated time-dependent <span class="hlt">flows</span> and stocks and assessed the effects of refrigerants (R-22, R-410a, and R-32) in household <span class="hlt">air</span> conditioners in Japan. It was found that stock of R-22 and R-410a peaked at 49,147t in 2000 and 55,994t in 2017, respectively. The largest <span class="hlt">flow</span> of R-22 and R-410a to waste phase occurred at 3417t/yr. in 2005 and 4011t/yr. in 2023, respectively. The total global warming potential (GWP) <span class="hlt">due</span> to refrigerant emissions increased from 3.6kt CO2 eq. in 1952 to 6999kt CO2 eq. in 2019, and then decreased to 5314kt CO2 eq. in 2030. The ozone depletion potential (ODP) peaked at 141t CFC-11 eq. in 2002. When substituting R-410a for R-22, the ODP decreased 50% while the GDP increased 8%. When substituting R-32 for R-410a, there was no effect on the ODP while the GDP decreased 6%. The human health damage <span class="hlt">due</span> to the global warming effect of refrigerant emission was much higher than that <span class="hlt">due</span> to the ozone depleting effect. The refrigerant emission in use and waste management phases dominated the human health damage. The dynamic estimation not only allows us to evaluate the performance of past policies but also supports the future sustainable management associated with the health effects of refrigerants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780007494','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780007494"><span>The momentum transfer of incompressible turbulent separated <span class="hlt">flow</span> <span class="hlt">due</span> to cavities with steps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>White, R. E.; Norton, D. J.</p> <p>1977-01-01</p> <p>An experimental study was conducted using a plate test bed having a turbulent boundary layer to determine the momentum transfer to the faces of step/cavity combinations on the plate. Experimental data were obtained from configurations including an isolated configuration and an array of blocks in tile patterns. A momentum transfer correlation model of pressure forces on an isolated step/cavity was developed with experimental results to relate <span class="hlt">flow</span> and geometry parameters. Results of the experiments reveal that isolated step/cavity excrecences do not have a unique and unifying parameter group <span class="hlt">due</span> in part to cavity depth effects and in part to width parameter scale effects. Drag predictions for tile patterns by a kinetic pressure empirical method predict experimental results well. Trends were not, however, predicted by a method of variable roughness density phenomenology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007APS..DFD.JN011B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007APS..DFD.JN011B"><span>Near-bed particle motion <span class="hlt">due</span> to turbulent <span class="hlt">flow</span> using image-processing techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhattacharya, Anindita; Mazumder, B. S.; Ojha, Satya P.</p> <p>2007-11-01</p> <p>This study investigates the behavior of particle motion over the rough bed surface <span class="hlt">due</span> to near-bed turbulence in an open channel <span class="hlt">flow</span> using image processing techniques. The instantaneous fluid velocity components are measured by 16MHz 3D-Micro acoustic Doppler velocimeter (ADV). High-speed Motion-Scope (HSMS) system has been used to record the motion-picture photography of the particles movement on the surface of the rough bed at the rate of 250 frames/sec. The recorded images are analyzed in the light of particle motions, trajectories, saltation heights and lengths of individual particles, angles of orientation and their interactions with the boundary using digital image processing techniques with the help of the software Image Pro-Plus (IPP).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21072380','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21072380"><span>Transition from laminar to turbulent drag in <span class="hlt">flow</span> <span class="hlt">due</span> to a vibrating quartz fork</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Blazkova, M.; Schmoranzer, D.; Skrbek, L.</p> <p>2007-02-15</p> <p><span class="hlt">Flow</span> <span class="hlt">due</span> to a commercially available vibrating quartz fork is studied in gaseous helium, He I and He II, over a wide range of temperatures and pressures. On increasing the driving force applied to the fork, the drag changes in character from laminar (characterized by a linear drive vs velocity dependence) to turbulent (characterized by a quadratic drive vs velocity dependence). We characterize this transition by a critical Reynolds number Re{sub cr}{sup {delta}}=U{sub cr}{delta}/{nu}, where U{sub cr} is the critical velocity, {nu} stands for the kinematic viscosity, {delta}={radical}(2{nu}/{omega}) is the viscous penetration depth, and {omega} is the angular frequency of oscillations. We have experimentally verified that the corresponding scaling U{sub cr}{proportional_to}{radical}({nu}{omega}) holds in a classical viscous fluid over two decades of {nu}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000APS..DFD.DP005V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000APS..DFD.DP005V"><span>On the stability of an accelerated coupled <span class="hlt">air</span>-water <span class="hlt">flow</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veron, Fabrice; Ierley, Glenn; Melville, W. Kendall</p> <p>2000-11-01</p> <p>We present the results of a study of the stability of the interface of an accelerated coupled <span class="hlt">air</span>-water <span class="hlt">flow</span>. We develop a general solution of the two-layer, laminar parallel <span class="hlt">flow</span> driven by a pressure gradient in the <span class="hlt">air</span>. The velocity profiles in both fluids are given by analytical functions for pressure gradients that can be represented as power series in time. The stability of the coupled <span class="hlt">flow</span> is then examined by solving the two layer Orr-Sommerfeld equations allowing for linear displacements of the interface. In the simple case of the linearly accelerating <span class="hlt">flow</span>, we find that the <span class="hlt">flow</span> is always stable for an <span class="hlt">air</span> velocity below 0.6 m s-1. Instabilities first appear in the form of surface waves with a phase speed of approximately 30 cm s-1 and a wavenumber of O(1) cm-1. In cases when the <span class="hlt">flow</span> in the <span class="hlt">air</span> is turbulent, and represented by a continuously differentiable analytical approximation of the log-linear mean velocity profile, we find that the <span class="hlt">flow</span> is rapidly unstable to surface waves. Comparisons are made with the previous computations of Kawai (1979) and Wheless and Csanady (1993), and with the measurements of Veron and Melville (2000).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LatJP..53b..20S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LatJP..53b..20S"><span>Experimental and Numerical Analysis of <span class="hlt">Air</span> <span class="hlt">Flow</span>, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sabanskis, A.; Virbulis, J.</p> <p>2016-04-01</p> <p>Monitoring of temperature, humidity and <span class="hlt">air</span> <span class="hlt">flow</span> velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an <span class="hlt">air-air</span> heat pump, <span class="hlt">air</span>-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of <span class="hlt">air</span> <span class="hlt">flow</span> and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and <span class="hlt">air</span> <span class="hlt">flow</span> distribution as well as thermal comfort.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3655160','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3655160"><span>An Open-Access Modeled Passenger <span class="hlt">Flow</span> Matrix for the Global <span class="hlt">Air</span> Network in 2010</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huang, Zhuojie; Wu, Xiao; Garcia, Andres J.; Fik, Timothy J.; Tatem, Andrew J.</p> <p>2013-01-01</p> <p>The expanding global <span class="hlt">air</span> network provides rapid and wide-reaching connections accelerating both domestic and international travel. To understand human movement patterns on the network and their socioeconomic, environmental and epidemiological implications, information on passenger <span class="hlt">flow</span> is required. However, comprehensive data on global passenger <span class="hlt">flow</span> remain difficult and expensive to obtain, prompting researchers to rely on scheduled flight seat capacity data or simple models of <span class="hlt">flow</span>. This study describes the construction of an open-access modeled passenger <span class="hlt">flow</span> matrix for all airports with a host city-population of more than 100,000 and within two transfers of <span class="hlt">air</span> travel from various publicly available <span class="hlt">air</span> travel datasets. Data on network characteristics, city population, and local area GDP amongst others are utilized as covariates in a spatial interaction framework to predict the <span class="hlt">air</span> transportation <span class="hlt">flows</span> between airports. Training datasets based on information from various transportation organizations in the United States, Canada and the European Union were assembled. A log-linear model controlling the random effects on origin, destination and the airport hierarchy was then built to predict passenger <span class="hlt">flows</span> on the network, and compared to the results produced using previously published models. Validation analyses showed that the model presented here produced improved predictive power and accuracy compared to previously published models, yielding the highest successful prediction rate at the global scale. Based on this model, passenger <span class="hlt">flows</span> between 1,491 airports on 644,406 unique routes were estimated in the prediction dataset. The airport node characteristics and estimated passenger <span class="hlt">flows</span> are freely available as part of the Vector-Borne Disease Airline Importation Risk (VBD-<span class="hlt">Air</span>) project at: www.vbd-<span class="hlt">air</span>.com/data. PMID:23691194</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23691194','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23691194"><span>An open-access modeled passenger <span class="hlt">flow</span> matrix for the global <span class="hlt">air</span> network in 2010.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Zhuojie; Wu, Xiao; Garcia, Andres J; Fik, Timothy J; Tatem, Andrew J</p> <p>2013-01-01</p> <p>The expanding global <span class="hlt">air</span> network provides rapid and wide-reaching connections accelerating both domestic and international travel. To understand human movement patterns on the network and their socioeconomic, environmental and epidemiological implications, information on passenger <span class="hlt">flow</span> is required. However, comprehensive data on global passenger <span class="hlt">flow</span> remain difficult and expensive to obtain, prompting researchers to rely on scheduled flight seat capacity data or simple models of <span class="hlt">flow</span>. This study describes the construction of an open-access modeled passenger <span class="hlt">flow</span> matrix for all airports with a host city-population of more than 100,000 and within two transfers of <span class="hlt">air</span> travel from various publicly available <span class="hlt">air</span> travel datasets. Data on network characteristics, city population, and local area GDP amongst others are utilized as covariates in a spatial interaction framework to predict the <span class="hlt">air</span> transportation <span class="hlt">flows</span> between airports. Training datasets based on information from various transportation organizations in the United States, Canada and the European Union were assembled. A log-linear model controlling the random effects on origin, destination and the airport hierarchy was then built to predict passenger <span class="hlt">flows</span> on the network, and compared to the results produced using previously published models. Validation analyses showed that the model presented here produced improved predictive power and accuracy compared to previously published models, yielding the highest successful prediction rate at the global scale. Based on this model, passenger <span class="hlt">flows</span> between 1,491 airports on 644,406 unique routes were estimated in the prediction dataset. The airport node characteristics and estimated passenger <span class="hlt">flows</span> are freely available as part of the Vector-Borne Disease Airline Importation Risk (VBD-<span class="hlt">Air</span>) project at: www.vbd-<span class="hlt">air</span>.com/data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4872534','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4872534"><span>The burden of COPD mortality <span class="hlt">due</span> to ambient <span class="hlt">air</span> pollution in Guangzhou, China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Li; Yang, Jun; Song, Yun-Feng; Chen, Ping-Yan; Ou, Chun-Quan</p> <p>2016-01-01</p> <p>Few studies have investigated the chronic obstructive pulmonary disease (COPD) mortality fraction attributable to <span class="hlt">air</span> pollution and modification by individual characteristics of <span class="hlt">air</span> pollution effects. We applied distributed lag non-linear models to assess the associations between <span class="hlt">air</span> pollution and COPD mortality in 2007–2011 in Guangzhou, China, and the total COPD mortality fraction attributable to <span class="hlt">air</span> pollution was calculated as well. We found that an increase of 10 μg/m3 in particulate matter with an aerodynamic diameter of 10 μm or less (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2) was associated with a 1.58% (95% confidence interval (CI): 0.12–3.06%), 3.45% (95% CI: 1.30–5.66%) and 2.35% (95% CI: 0.42–4.32%) increase of COPD mortality over a lag of 0–15 days, respectively. Greater <span class="hlt">air</span> pollution effects were observed in the elderly, males and residents with low educational attainment. The results showed 10.91% (95% CI: 1.02–9.58%), 12.71% (95% CI: 5.03–19.85%) and 13.38% (95% CI: 2.67–22.84%) COPD mortality was attributable to current PM10, SO2 and NO2 exposure, respectively. In conclusion, the associations between <span class="hlt">air</span> pollution and COPD mortality differed by individual characteristics. There were remarkable COPD mortality burdens attributable to <span class="hlt">air</span> pollution in Guangzhou. PMID:27195597</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060056404','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060056404"><span>An Experimental Investigation of Several Low-Drag Wing-Nacelle Combinations with Internal <span class="hlt">Air</span> <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allen, H. Julian; Frick, Charles W.; Erickson, Myles D.</p> <p>1945-01-01</p> <p>The results of an experimental investigation of several low-drag wing-nacelle combinations, incorporating internal <span class="hlt">air-flow</span> systems, are presented. The external-drag increments <span class="hlt">due</span> to these nacelles are between one-half and two-thirds of those of conventional nacelle forms. This improvement is accomplished with only minor effects on the lift and moment characteristics of the wing. The procedure employed to determine the external shape of such low-drag nacelles is considered in detail. The design of an efficient internal-<span class="hlt">flow</span> system with or without a blower or throttle, presents no serious problems. The energy losses in the expansion before the engine and the contraction thereafter can be kept small. It is believed that these nacelles have a wide application in housing engine pusher-propeller units and, with some alteration, jet-propulsion devices. It is probable that the low external drags may not be realized if such nacelles are used with a tractor propeller because of the high level of turbulence in the propeller slipstream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930090837','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930090837"><span>On improvement of <span class="hlt">air</span> <span class="hlt">flow</span> in wind tunnels</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wieselsberger, C</p> <p>1928-01-01</p> <p>The most important aerodynamical qualities that should be aimed at in wind tunnel design, are as follows: 1) constant and parallel direction of <span class="hlt">flow</span>; 2) uniform velocity across all sections; 3) absence of turbulent motion; 4) constant velocity of <span class="hlt">flow</span>. The above-mentioned qualities are all realized in a high degree in the Gottingen type of wind tunnel, with a parallel portion before the working section, the cross section of which is steadily reduced. It is shown in what follows, that the system can be applied to other wind tunnels, such as the N.P.L. or Eiffel type.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...637074C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...637074C"><span>Population exposure to hazardous <span class="hlt">air</span> quality <span class="hlt">due</span> to the 2015 fires in Equatorial Asia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crippa, P.; Castruccio, S.; Archer-Nicholls, S.; Lebron, G. B.; Kuwata, M.; Thota, A.; Sumin, S.; Butt, E.; Wiedinmyer, C.; Spracklen, D. V.</p> <p>2016-11-01</p> <p>Vegetation and peatland fires cause poor <span class="hlt">air</span> quality and thousands of premature deaths across densely populated regions in Equatorial Asia. Strong El-Niño and positive Indian Ocean Dipole conditions are associated with an increase in the frequency and intensity of wildfires in Indonesia and Borneo, enhancing population exposure to hazardous concentrations of smoke and <span class="hlt">air</span> pollutants. Here we investigate the impact on <span class="hlt">air</span> quality and population exposure of wildfires in Equatorial Asia during Fall 2015, which were the largest over the past two decades. We performed high-resolution simulations using the Weather Research and Forecasting model with Chemistry based on a new fire emission product. The model captures the spatio-temporal variability of extreme pollution episodes relative to space- and ground-based observations and allows for identification of pollution sources and transport over Equatorial Asia. We calculate that high particulate matter concentrations from fires during Fall 2015 were responsible for persistent exposure of 69 million people to unhealthy <span class="hlt">air</span> quality conditions. Short-term exposure to this pollution may have caused 11,880 (6,153–17,270) excess mortalities. Results from this research provide decision-relevant information to policy makers regarding the impact of land use changes and human driven deforestation on fire frequency and population exposure to degraded <span class="hlt">air</span> quality.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7279742','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7279742"><span>Respiratory alterations <span class="hlt">due</span> to urban <span class="hlt">air</span> pollution: An experimental study in rats</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Saldiva, P.H.N.; King, M.; Delmonte, V.L.C.; Macchione, M.; Parada, M.A.C.; Daliberto, M.L.; Sakae, R.S.; Criado, P.M.P.; Silveira, P.L.P.; Zin, W.A.; Boehm, G.M. Univ. of Alberta, Edmonton )</p> <p>1992-02-01</p> <p>In order to assess the adverse effects of urban levels of <span class="hlt">air</span> pollution, rats were used as biological indicators in a chronic exposure experiment. Animals were housed for 6 months in the center of Sao Paulo and were compared to controls kept for the same period in a clean area. Pollution levels were obtained from a State <span class="hlt">air</span> pollution monitoring station, 200 m distant from the exposure place, which provided the levels of CO, SO{sub 2}, particulates, and ozone. The animals were submitted to several tests focusing on the respiratory system, comprising pulmonary function tests, studies on mucociliary clearance and mucus rheology, histochemical evaluation of airways, bronchoalveolar lavage, and ultrastructural studies of the epithelium of the airways. Rats exposed to <span class="hlt">air</span> pollution developed secretory cell hyperplasia in the airways, ultrastructural ciliary alterations, and a more rigid mucus, changes that caused mucociliary clearance impairment. In addition, nasal resistance and the number of inflammatory cells recovered by bronchoalveolar lavage were increased in <span class="hlt">air</span> pollution exposed animals. The results obtained in the present investigation suggest that chronic exposure to urban levels of <span class="hlt">air</span> pollution may cause respiratory lesions in rats.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27848989','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27848989"><span>Population exposure to hazardous <span class="hlt">air</span> quality <span class="hlt">due</span> to the 2015 fires in Equatorial Asia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Crippa, P; Castruccio, S; Archer-Nicholls, S; Lebron, G B; Kuwata, M; Thota, A; Sumin, S; Butt, E; Wiedinmyer, C; Spracklen, D V</p> <p>2016-11-16</p> <p>Vegetation and peatland fires cause poor <span class="hlt">air</span> quality and thousands of premature deaths across densely populated regions in Equatorial Asia. Strong El-Niño and positive Indian Ocean Dipole conditions are associated with an increase in the frequency and intensity of wildfires in Indonesia and Borneo, enhancing population exposure to hazardous concentrations of smoke and <span class="hlt">air</span> pollutants. Here we investigate the impact on <span class="hlt">air</span> quality and population exposure of wildfires in Equatorial Asia during Fall 2015, which were the largest over the past two decades. We performed high-resolution simulations using the Weather Research and Forecasting model with Chemistry based on a new fire emission product. The model captures the spatio-temporal variability of extreme pollution episodes relative to space- and ground-based observations and allows for identification of pollution sources and transport over Equatorial Asia. We calculate that high particulate matter concentrations from fires during Fall 2015 were responsible for persistent exposure of 69 million people to unhealthy <span class="hlt">air</span> quality conditions. Short-term exposure to this pollution may have caused 11,880 (6,153-17,270) excess mortalities. Results from this research provide decision-relevant information to policy makers regarding the impact of land use changes and human driven deforestation on fire frequency and population exposure to degraded <span class="hlt">air</span> quality.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...49e2007B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...49e2007B"><span>Dynamic water behaviour <span class="hlt">due</span> to one trapped <span class="hlt">air</span> pocket in a laboratory pipeline apparatus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bergant, A.; Karadžić, U.; Tijsseling, A.</p> <p>2016-11-01</p> <p>Trapped <span class="hlt">air</span> pockets may cause severe operational problems in hydropower and water supply systems. A locally isolated <span class="hlt">air</span> pocket creates distinct amplitude, shape and timing of pressure pulses. This paper investigates dynamic behaviour of a single trapped <span class="hlt">air</span> pocket. The <span class="hlt">air</span> pocket is incorporated as a boundary condition into the discrete gas cavity model (DGCM). DGCM allows small gas cavities to form at computational sections in the method of characteristics (MOC). The growth of the pocket and gas cavities is described by the water hammer compatibility equation(s), the continuity equation for the cavity volume, and the equation of state of an ideal gas. Isentropic behaviour is assumed for the trapped gas pocket and an isothermal bath for small gas cavities. Experimental investigations have been performed in a laboratory pipeline apparatus. The apparatus consists of an upstream end high-pressure tank, a horizontal steel pipeline (total length 55.37 m, inner diameter 18 mm), four valve units positioned along the pipeline including the end points, and a downstream end tank. A trapped <span class="hlt">air</span> pocket is captured between two ball valves at the downstream end of the pipeline. The transient event is initiated by rapid opening of the upstream end valve; the downstream end valve stays closed during the event. Predicted and measured results for a few typical cases are compared and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5111049','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5111049"><span>Population exposure to hazardous <span class="hlt">air</span> quality <span class="hlt">due</span> to the 2015 fires in Equatorial Asia</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Crippa, P.; Castruccio, S.; Archer-Nicholls, S.; Lebron, G. B.; Kuwata, M.; Thota, A.; Sumin, S.; Butt, E.; Wiedinmyer, C.; Spracklen, D. V.</p> <p>2016-01-01</p> <p>Vegetation and peatland fires cause poor <span class="hlt">air</span> quality and thousands of premature deaths across densely populated regions in Equatorial Asia. Strong El-Niño and positive Indian Ocean Dipole conditions are associated with an increase in the frequency and intensity of wildfires in Indonesia and Borneo, enhancing population exposure to hazardous concentrations of smoke and <span class="hlt">air</span> pollutants. Here we investigate the impact on <span class="hlt">air</span> quality and population exposure of wildfires in Equatorial Asia during Fall 2015, which were the largest over the past two decades. We performed high-resolution simulations using the Weather Research and Forecasting model with Chemistry based on a new fire emission product. The model captures the spatio-temporal variability of extreme pollution episodes relative to space- and ground-based observations and allows for identification of pollution sources and transport over Equatorial Asia. We calculate that high particulate matter concentrations from fires during Fall 2015 were responsible for persistent exposure of 69 million people to unhealthy <span class="hlt">air</span> quality conditions. Short-term exposure to this pollution may have caused 11,880 (6,153–17,270) excess mortalities. Results from this research provide decision-relevant information to policy makers regarding the impact of land use changes and human driven deforestation on fire frequency and population exposure to degraded <span class="hlt">air</span> quality. PMID:27848989</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFD.R6005Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFD.R6005Z"><span>Effect of <span class="hlt">air</span> on water capillary <span class="hlt">flow</span> in silica nanochannels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zambrano, Harvey; Walther, Jens; Oyarzua, Elton</p> <p>2013-11-01</p> <p>Capillarity is a classical topic in fluid dynamics. The fundamental relationship between capillarity and surface tension is solidly established. Nevertheless, capillarity is an active research area especially as the miniaturization of devices is reaching the molecular scale. Currently, with the fabrication of microsystems integrated by nanochannels, a thorough understanding of the transport of fluids in nanoconfinement is required for a successful operation of the functional parts of such devices. In this work, Molecular Dynamics simulations are conducted to study the spontaneous imbibition of water in sub 10 nm silica channels. The capillary filling speed is computed in channels subjected to different <span class="hlt">air</span> pressures. In order to describe the interactions between the species, an effective force field is developed, which is calibrated by reproducing the water contact angle. The results show that the capillary filling speed qualitatively follows the classical Washburn model, however, quantitatively it is lower than expected. Furthermore, it is observed that the deviations increase as <span class="hlt">air</span> pressure is higher. We attribute the deviations to amounts of <span class="hlt">air</span> trapped at the silica-water interface which leads to changes in the dynamics contact angle of the water meniscus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/46025','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/46025"><span>Application of a 2D <span class="hlt">air</span> <span class="hlt">flow</span> model to soil vapor extraction and bioventing case studies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mohr, D.H.; Merz, P.H.</p> <p>1995-05-01</p> <p>Soil vapor extraction (SVE) is frequently the technology of choice to clean up hydrocarbon contamination in unsaturated soil. A two-dimensional <span class="hlt">air</span> <span class="hlt">flow</span> model provides a practical tool to evaluate pilot test data and estimate remediation rates for soil vapor extraction systems. The model predictions of soil vacuum versus distance are statistically compared to pilot test data for 65 SVE wells at 44 sites. For 17 of 21 sites where there was asphalt paving, the best agreement was obtained for boundary conditions with no barrier to <span class="hlt">air</span> <span class="hlt">flow</span> at the surface. The model predictions of <span class="hlt">air</span> <span class="hlt">flow</span> rates and stream lines around the well allow an estimate of the gasoline removal rates by both evaporation and bioremediation. The model can be used to quickly estimate the effective radius of influence, defined here as the maximum distance from the well where there is enough <span class="hlt">air</span> <span class="hlt">flow</span> to remove the contaminant present within the allowable time. The effective radius of influence is smaller than a radius of influence defined by soil vacuum only. For a case study, in situ bioremediation rates were estimated using the <span class="hlt">air</span> <span class="hlt">flow</span> model and compared to independent estimates based on changes in soil temperature. These estimate bioremediation rates for heavy fuel oil ranged from 2.5 to 11 mg oil degraded per kg soil per day, in agreement with values in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20502753','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20502753"><span>Ambient cold <span class="hlt">air</span> decreased nasal mucosa blood <span class="hlt">flow</span> measured by laser Doppler flowmeter.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chu, Yueng-Hsiang; Lu, Da-Wen; Wang, Hsing-Won</p> <p>2010-06-01</p> <p>With its potentially conflicting physiological roles of both <span class="hlt">air</span>-conditioning and body-heat recovery, the response of nasal mucosa blood <span class="hlt">flow</span> (NMBF) to ambient cold <span class="hlt">air</span> is not well understood. To evaluate the NMBF in response to cold ambient <span class="hlt">air</span>. The NMBF was continuously measured by laser Doppler flowmetry in nine participants exposed to different <span class="hlt">air</span> temperatures (24 degrees C and 4 degrees C). The NMBF significantly decreased at 4 degrees C compared with that at 24 degrees C (p < 0.01). The response to ambient cold <span class="hlt">air</span> in the nasal microcirculation is similar to that of the body-surface blood vessels, suggesting that body-heat recovery rather than <span class="hlt">air</span>-conditioning is the predominant function.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/23864','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/23864"><span>Spatial distribution of impacts to channel bed mobility <span class="hlt">due</span> to <span class="hlt">flow</span> regulation, Kootenai River, USA</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Michael Burke; Klaus Jorde; John M. Buffington; Jeffrey H. Braatne; Rohan Benjakar</p> <p>2006-01-01</p> <p>The regulated hydrograph of the Kootenai River between Libby Dam and Kootenay Lake has altered the natural <span class="hlt">flow</span> regime, resulting in a significant decrease in maximum <span class="hlt">flows</span> (60% net reduction in median 1-day annual maximum, and 77%-84% net reductions in median monthly <span class="hlt">flows</span> for the historic peak <span class="hlt">flow</span> months of May and June, respectively). Other key hydrologic...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPC.1889b0045U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1889b0045U"><span>Calibration of nozzle for <span class="hlt">air</span> mass <span class="hlt">flow</span> measurement</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uher, Jan; Kanta, Lukáš</p> <p>2017-09-01</p> <p>The effort to make calibration measurement of mass <span class="hlt">flow</span> through a nozzle was not satisfying. Traversing across the pipe radius with Pitot probe was done. The presence of overshoot behind the bend in the pipe was found. The overshoot led to an asymmetric velocity profile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25921636','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25921636"><span>Experimental and numerical investigations on reliability of <span class="hlt">air</span> barrier on oil containment in <span class="hlt">flowing</span> water.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lu, Jinshu; Xu, Zhenfeng; Xu, Song; Xie, Sensen; Wu, Haoxiao; Yang, Zhenbo; Liu, Xueqiang</p> <p>2015-06-15</p> <p><span class="hlt">Air</span> barriers have been recently developed and employed as a new type of oil containment boom. This paper presents systematic investigations on the reliability of <span class="hlt">air</span> barriers on oil containments with the involvement of <span class="hlt">flowing</span> water, which represents the commonly-seen shearing current in reality, by using both laboratory experiments and numerical simulations. Both the numerical and experimental investigations are carried out in a model scale. In the investigations, a submerged pipe with apertures is installed near the bottom of a tank to generate the <span class="hlt">air</span> bubbles forming the <span class="hlt">air</span> curtain; and, the shearing water <span class="hlt">flow</span> is introduced by a narrow inlet near the mean free surface. The effects of the aperture configurations (including the size and the spacing of the aperture) and the location of the pipe on the effectiveness of the <span class="hlt">air</span> barrier on preventing oil spreading are discussed in details with consideration of different <span class="hlt">air</span> discharges and velocities of the <span class="hlt">flowing</span> water. The research outcome provides a foundation for evaluating and/or improve the reliability of a <span class="hlt">air</span> barrier on preventing spilled oil from further spreading. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MS%26E...72d2047Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MS%26E...72d2047Y"><span>Numerical simulation and analysis of the internal <span class="hlt">flow</span> in a Francis turbine with <span class="hlt">air</span> admission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, A.; Luo, X. W.; Ji, B.</p> <p>2015-01-01</p> <p>In case of hydro turbines operated at part-load condition, vortex ropes usually occur in the draft tube, and consequently generate violent pressure fluctuation. This unsteady <span class="hlt">flow</span> phenomenon is believed harmful to hydropower stations. This paper mainly treats the internal <span class="hlt">flow</span> simulation in the draft tube of a Francis turbine. In order to alleviate the pressure fluctuation induced by the vortex rope, <span class="hlt">air</span> admission from the main shaft center is applied, and the water-<span class="hlt">air</span> two phase <span class="hlt">flow</span> in the entire <span class="hlt">flow</span> passage of a model turbine is simulated based on a homogeneous <span class="hlt">flow</span> assumption and SST k-ω turbulence model. It is noted that the numerical simulation reasonably predicts the pressure fluctuations in the draft tube, which agrees fairly well with experimental data. The analysis based on the vorticity transport equation shows that the vortex dilation plays a major role in the vortex evolution with <span class="hlt">air</span> admission in the turbine draft tube, and there is large value of vortex dilation along the vortex rope. The results show that the aeration with suitable <span class="hlt">air</span> volume fraction can depress the vortical <span class="hlt">flow</span>, and alleviate the pressure fluctuation in the draft tube.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE10008E..0ZN','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE10008E..0ZN"><span>Investigation of <span class="hlt">air</span> pollution and regional climate change <span class="hlt">due</span> to anthropogenic aerosols</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakata, Makiko; Sano, Itaru; Mukai, Sonoyo</p> <p>2016-10-01</p> <p>Increased emissions of anthropogenic aerosols associated with economic growth can lead to increased concentrations of hazardous <span class="hlt">air</span> pollutants. In particular, large cities in East Asia have experienced numerous heavy haze episodes. Atmospheric aerosol distributions in East Asia are complex, being influenced by both natural phenomena and human activity, with urban areas in particular being dominated by fine anthropogenic aerosols released from diesel-powered vehicles and industrial activity. In Japan, <span class="hlt">air</span> pollution levels have been reduced; nevertheless, in recent years, there is increasing concern regarding <span class="hlt">air</span> pollution caused by fine particulate matter. The origins of <span class="hlt">air</span> pollution were examined, focusing on the comparison between aerosol properties observed from satellites and that on the ground. Because of their short life spans, concentrations of anthropogenic aerosols are highest over the source regions, and as a result, the climatic impacts of anthropogenic aerosols are also found to be most pronounced in these regions. In this study, aerosol impacts on climate are assessed by numerical model simulations. The direct effects of aerosols include reduced solar radiation, and hence a decrease in surface temperatures. In addition to these changes in the radiation budget, aerosols have a significant potential to change cloud and precipitation fields. These climatic responses to aerosols can manifest far from their source regions with high industrial activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19377742','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19377742"><span>[Perception of health risks <span class="hlt">due</span> to <span class="hlt">air</span> pollution among adolescents in Mexico City].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Catalán-Vázquez, Minerva; Riojas-Rodríguez, Horacio; Jarillo-Soto, Edgar C; Delgadillo-Gutiérrez, Héctor Javier</p> <p>2009-01-01</p> <p>Analyze the relations established between <span class="hlt">air</span> pollution and health-disease-death in a sample of students in Mexico City. Survey of 1274 students from 14 secondary schools in five areas in Mexico City was conducted between March and April of 2003. We used a multi-stage sampling, based in a basic geostatistical areas (AGEB). A total of 84.4% believed that Mexico City has a high, or very high <span class="hlt">air</span> pollution; that valuation decreases as it approaches the most immediate place in which the students live. The health risks range from effects on respiratory health, 66.9%, to other effects on daily life, 2.2%. The predictors that <span class="hlt">air</span> pollution is perceived as serious/very serious are: 1) that they associate it with the possibility of causing death (OR= 1.35, 95% CI=1.02-1.77), and 2) that they attend schools located in the La Merced zone, (OR= 2.23, 95% CI= 1.56-3.21). Determinants of perception, such as gender, zone where the school is located and the differences in <span class="hlt">air</span> quality perceived in the city/area/schools, suggest that focalizing components must be involved in environmental policies, in order to make environmental programs more effective at the local level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24195736','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24195736"><span><span class="hlt">Air</span> quality and climate impacts <span class="hlt">due</span> to CNG conversion of motor vehicles in Dhaka, Bangladesh.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wadud, Zia; Khan, Tanzila</p> <p>2013-12-17</p> <p>Dhaka had recently experienced rapid conversion of its motor vehicle fleet to run on compressed natural gas (CNG). This paper quantifies ex-post the <span class="hlt">air</span> quality and climate benefits of the CNG conversion policy, including monetary valuations, through an impact pathway approach. Around 2045 (1665) avoided premature deaths in greater Dhaka (City Corporation) can be attributed to <span class="hlt">air</span> quality improvements from the CNG conversion policy in 2010, resulting in a saving of around USD 400 million. Majority of these health benefits resulted from the conversion of high-emitting diesel vehicles. CNG conversion was clearly detrimental from climate change perspective using the changes in CO2 and CH4 only (CH4 emissions increased); however, after considering other global pollutants (especially black carbon), the climate impact was ambiguous. Uncertainty assessment using input distributions and Monte Carlo simulation along with a sensitivity analysis show that large uncertainties remain for climate impacts. For our most likely estimate, there were some climate costs, valued at USD 17.7 million, which is an order of magnitude smaller than the <span class="hlt">air</span> quality benefits. This indicates that such policies can and should be undertaken on the grounds of improving local <span class="hlt">air</span> pollution alone and that precautions should be taken to reduce the potentially unintended increases in GHG emissions or other unintended effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19398506','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19398506"><span><span class="hlt">Flow</span> and performance of an <span class="hlt">air</span>-curtain biological safety cabinet.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Rong Fung; Chou, Chun I</p> <p>2009-06-01</p> <p>Using laser-assisted smoke <span class="hlt">flow</span> visualization and tracer gas concentration detection techniques, this study examines aerodynamic <span class="hlt">flow</span> properties and the characteristics of escape from containment, inward dispersion, and cross-cabinet contamination of a biological safety cabinet installed with an <span class="hlt">air</span> curtain across the front aperture. The experimental method partially simulates the NSF/ANSI 49 standards with the difference that the biological tracer recommended by these standards is replaced by a mixture of 10% SF(6) in N(2). The <span class="hlt">air</span> curtain is set up across the cabinet aperture plane by means of a narrow planar jet issued from the lower edge of the sash and a suction <span class="hlt">flow</span> going through a suction slot installed at the front edge of the work surface. Varying the combination of jet velocity, suction <span class="hlt">flow</span> velocity, and descending <span class="hlt">flow</span> velocity reveals three types of characteristic <span class="hlt">flow</span> modes: 'straight curtain', 'slightly concave curtain', and 'severely concave curtain'. Operating the cabinet in the straight curtain mode causes the <span class="hlt">air</span> curtain to impinge on the doorsill and therefore induces serious escape from containment. In the severely concave curtain mode, drastically large inward dispersion and cross-cabinet contamination were observed because environmental <span class="hlt">air</span> entered into the cabinet and a three-dimensional vortical <span class="hlt">flow</span> structure formed in the cabinet. The slightly concave curtain mode presents a smooth and two-dimensional <span class="hlt">flow</span> pattern with an <span class="hlt">air</span> curtain separating the outside atmosphere from the inside space of the cabinet, and therefore exhibited negligibly small escape from containment, inward dispersion, and cross-cabinet contamination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PlST...18..485Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PlST...18..485Z"><span>Investigation on Plasma Jet <span class="hlt">Flow</span> Phenomena During DC <span class="hlt">Air</span> Arc Motion in Bridge-Type Contacts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhai, Guofu; Bo, Kai; Chen, Mo; Zhou, Xue; Qiao, Xinlei</p> <p>2016-05-01</p> <p>Arc plasma jet <span class="hlt">flow</span> in the <span class="hlt">air</span> was investigated under a bridge-type contacts in a DC 270 V resistive circuit. We characterized the arc plasma jet <span class="hlt">flow</span> appearance at different currents by using high-speed photography, and two polished contacts were used to search for the relationship between roughness and plasma jet <span class="hlt">flow</span>. Then, to make the nature of arc plasma jet <span class="hlt">flow</span> phenomena clear, a simplified model based on magnetohydrodynamic (MHD) theory was established and calculated. The simulated DC arc plasma was presented with the temperature distribution and the current density distribution. Furthermore, the calculated arc <span class="hlt">flow</span> velocity field showed that the circular vortex was an embodiment of the arc plasma jet <span class="hlt">flow</span> progress. The combined action of volume force and contact surface was the main reason of the arc jet <span class="hlt">flow</span>. supported by National Natural Science Foundation of China (Nos. 51307030, 51277038)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPS...306..692G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPS...306..692G"><span>Investigation of crossover processes in a unitized bidirectional vanadium/<span class="hlt">air</span> redox <span class="hlt">flow</span> battery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>grosse Austing, Jan; Nunes Kirchner, Carolina; Komsiyska, Lidiya; Wittstock, Gunther</p> <p>2016-02-01</p> <p>In this paper the losses in coulombic efficiency are investigated for a vanadium/<span class="hlt">air</span> redox <span class="hlt">flow</span> battery (VARFB) comprising a two-layered positive electrode. Ultraviolet/visible (UV/Vis) spectroscopy is used to monitor the concentrations cV2+ and cV3+ during operation. The most likely cause for the largest part of the coulombic losses is the permeation of oxygen from the positive to the negative electrode followed by an oxidation of V2+ to V3+. The total vanadium crossover is followed by inductively coupled plasma mass spectroscopy (ICP-MS) analysis of the positive electrolyte after one VARFB cycle. During one cycle 6% of the vanadium species initially present in the negative electrolyte are transferred to the positive electrolyte, which can account at most for 20% of the coulombic losses. The diffusion coefficients of V2+ and V3+ through Nafion® 117 are determined as DV2+ ,N 117 = 9.05 ·10-6 cm2 min-1 and DV3+ ,N 117 = 4.35 ·10-6 cm2 min-1 and are used to calculate vanadium crossover <span class="hlt">due</span> to diffusion which allows differentiation between vanadium crossover <span class="hlt">due</span> to diffusion and migration/electroosmotic convection. In order to optimize coulombic efficiency of VARFB, membranes need to be designed with reduced oxygen permeation and vanadium crossover.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA083480','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA083480"><span>Burning of Graphite in an <span class="hlt">Air</span> <span class="hlt">Flow</span> at High Temperatures</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1979-08-24</p> <p>value by only 1-2’. Fure ~ ---- C _ M 02 Ŕ I 611 :7a 168 Ls-io raphy 1. A a 3 it M o B H. A. 0 npe~cTaaeaza AnccorksnpoBamaoro Boaziyxa a nalecme...o o r e J. A.. Z Io t n i k M. Combustion of Carbon in <span class="hlt">Air</span> Stream. ARS Journal 1961, vol. 31, Mi 10, p. 1388. 9. 111 en H u x o B B. B. PacqeT</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930091600','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930091600"><span><span class="hlt">Air</span> <span class="hlt">Flow</span> in a Separating Laminar Boundary Layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schubauer, G B</p> <p>1936-01-01</p> <p>The speed distribution in a laminar boundary layer on the surface of an elliptic cylinder, of major and minor axes 11.78 and 3.98 inches, respectively, has been determined by means of a hot-wire anemometer. The direction of the impinging <span class="hlt">air</span> stream was parallel to the major axis. Special attention was given to the region of separation and to the exact location of the point of separation. An approximate method, developed by K. Pohlhausen for computing the speed distribution, the thickness of the layer, and the point of separation, is described in detail; and speed-distribution curves calculated by this method are presented for comparison with experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4551065','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4551065"><span><span class="hlt">Flow</span> characteristics of an inclined <span class="hlt">air</span>-curtain range hood in a draft</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>CHEN, Jia-Kun</p> <p>2015-01-01</p> <p>The inclined <span class="hlt">air</span>-curtain technology was applied to build an inclined <span class="hlt">air</span>-curtain range hood. A draft generator was applied to affect the inclined <span class="hlt">air</span>-curtain range hood in three directions: lateral (θ=0°), oblique (θ=45°), and front (θ=90°). The three suction <span class="hlt">flow</span> rates provided by the inclined <span class="hlt">air</span>-curtain range hood were 10.1, 10.9, and 12.6 m3/min. The laser-assisted <span class="hlt">flow</span> visualization technique and the tracer-gas test method were used to investigate the performance of the range hood under the influence of a draft. The results show that the inclined <span class="hlt">air</span>-curtain range hood has a strong ability to resist the negative effect of a front draft until the draft velocity is greater than 0.5 m/s. The oblique draft affected the containment ability of the inclined <span class="hlt">air</span>-curtain range hood when the draft velocity was larger than 0.3 m/s. When the lateral draft effect was applied, the capture efficiency of the inclined <span class="hlt">air</span>-curtain range hood decreased quickly in the draft velocity from 0.2 m/s to 0.3 m/s. However, the capture efficiencies of the inclined <span class="hlt">air</span>-curtain range hood under the influence of the front draft were higher than those under the influence of the oblique draft from 0.3 m/s to 0.5 m/s. PMID:25810445</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17280560','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17280560"><span>Determination of ethane, pentane and isoprene in exhaled <span class="hlt">air</span>--effects of breath-holding, <span class="hlt">flow</span> rate and purified <span class="hlt">air</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lärstad, M A E; Torén, K; Bake, B; Olin, A-C</p> <p>2007-01-01</p> <p>Exhaled ethane, pentane and isoprene have been proposed as biomarkers of oxidative stress. The objectives were to explore whether ethane, pentane and isoprene are produced within the airways and to explore the effect of different sampling parameters on analyte concentrations. The <span class="hlt">flow</span> dependency of the analyte concentrations, the concentrations in dead-space and alveolar <span class="hlt">air</span> after breath-holding and the influence of inhaling purified <span class="hlt">air</span> on analyte concentrations were investigated. The analytical method involved thermal desorption from sorbent tubes and gas chromatography. The studied group comprised 13 subjects with clinically stable asthma and 14 healthy controls. Ethane concentrations decreased slightly, but significantly, at higher <span class="hlt">flow</span> rates in subjects with asthma (P = 0.0063) but not in healthy controls. Pentane levels were increased at higher <span class="hlt">flow</span> rates both in healthy and asthmatic subjects (P = 0.022 and 0.0063 respectively). Isoprene levels were increased at higher <span class="hlt">flow</span> rates, but only significantly in healthy subjects (P = 0.0034). After breath-holding, no significant changes in ethane levels were observed. Pentane and isoprene levels increased significantly after 20 s of breath-holding. Inhalation of purified <span class="hlt">air</span> before exhalation resulted in a substantial decrease in ethane levels, a moderate decrease in pentane levels and an increase in isoprene levels. The major fractions of exhaled ethane, pentane and isoprene seem to be of systemic origin. There was, however, a tendency for ethane to be <span class="hlt">flow</span> rate dependent in asthmatic subjects, although to a very limited extent, suggesting that small amounts of ethane may be formed in the airways.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA621657','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA621657"><span>Diagnostics of Unseeded <span class="hlt">Air</span> and Nitrogen <span class="hlt">Flows</span> by Molecular Tagging</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2015-07-21</p> <p>estimate must be corrected to take into account the reduced Rayleigh cross section of the atomic nitrogen , which is measured using the depolarization...collaboration has focused on the application of FLEET to measurements in the National Trans-sonic Facility, which operates with cold nitrogen . Tests have... measurement of core and boundary layer properties in supersonic and hypersonic nitrogen <span class="hlt">flows</span>. For this work the Princeton kHz laser system was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21151214','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21151214"><span>Experimental investigation of characteristics of a diffusion flame established over liquid ethanol surface under opposed <span class="hlt">air</span> <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sen, Anirudh; Raghavan, Vasudevan; Shet, U.S.P.</p> <p>2009-03-15</p> <p>A preliminary study of the shape and the extinction characteristics of a diffusion flame established over a circular liquid fuel surface under the influence of an opposed <span class="hlt">air</span> <span class="hlt">flow</span>, is presented. Renewable liquid fuel such as ethanol is employed. A simple heterogeneous combustion setup, which consists of a cylindrical tube containing ethanol located at the bottom, is exposed to an opposed <span class="hlt">air</span> <span class="hlt">flow</span> from a coaxial circular pipe of same size located at the top at a fixed separation distance. Axial and radial extents of flame for different <span class="hlt">air</span> <span class="hlt">flow</span> rates are qualitatively analyzed. Burning rates of ethanol for different separation distances and <span class="hlt">air</span> <span class="hlt">flow</span> rates are recorded. For a fixed separation distance, at a particular <span class="hlt">air</span> <span class="hlt">flow</span> rate the flame extinction takes place. Extinction <span class="hlt">air</span> <span class="hlt">flow</span> rates and corresponding strain rates for different separation distances are presented. (author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/862877','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/862877"><span><span class="hlt">Flow</span> directing means for <span class="hlt">air</span>-cooled transformers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Jallouk, Philip A.</p> <p>1977-01-01</p> <p>This invention relates to improvements in systems for force-cooling transformers of the kind in which an outer helical winding and an insulation barrier nested therein form an axially extending annular passage for cooling-fluid <span class="hlt">flow</span>. In one form of the invention a tubular shroud is positioned about the helical winding to define an axially extending annular chamber for cooling-fluid <span class="hlt">flow</span>. The chamber has a width in the range of from about 4 to 25 times that of the axially extending passage. Two baffles extend inward from the shroud to define with the helical winding two annular <span class="hlt">flow</span> channels having hydraulic diameters smaller than that of the chamber. The inlet to the chamber is designed with a hydraulic diameter approximating that of the coolant-entrance end of the above-mentioned annular passage. As so modified, transformers of the kind described can be operated at significantly higher load levels without exceeding safe operating temperatures. In some instances the invention permits continuous operation at 200% of the nameplate rating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/933177','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/933177"><span>Implications of <span class="hlt">Air</span> Ingress Induced by Density-Difference Driven Stratified <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chang Oh; Eung Soo Kim; Richard Schultz; David Petti; C. P. Liou</p> <p>2008-06-01</p> <p>One of the design basis accidents for the Next Generation Nuclear Plant (NGNP), a high temperature gas-cooled reactor, is <span class="hlt">air</span> ingress subsequent to a pipe break. Following a postulated double-ended guillotine break in the hot duct, and the subsequent depressurization to nearly reactor cavity pressure levels, <span class="hlt">air</span> present in the reactor cavity will enter the reactor vessel via density-gradient-driven-stratified <span class="hlt">flow</span>. Because of the significantly higher molecular weight and lower initial temperature of the reactor cavity <span class="hlt">air</span>-helium mixture, in contrast to the helium in the reactor vessel, the <span class="hlt">air</span>-helium mixture in the cavity always has a larger density than the helium discharging from the reactor vessel through the break into the reactor cavity. In the later stages of the helium blowdown, the momentum of the helium <span class="hlt">flow</span> decreases sufficiently for the heavier cavity <span class="hlt">air</span>-helium mixture to intrude into the reactor vessel lower plenum through the lower portion of the break. Once it has entered, the heavier gas will pool at the bottom of the lower plenum. From there it will move upwards into the core via diffusion and density-gradient effects that stem from heating the <span class="hlt">air</span>-helium mixture and from the pressure differences between the reactor cavity and the reactor vessel. This scenario (considering density-gradient-driven stratified <span class="hlt">flow</span>) is considerably different from the heretofore commonly used scenario that attributes movement of <span class="hlt">air</span> into the reactor vessel and from thence to the core region via diffusion. When density-gradient-driven stratified <span class="hlt">flow</span> is considered as a contributing phenomena for <span class="hlt">air</span> ingress into the reactor vessel, the following factors contribute to a much earlier natural circulation-phase in the reactor vessel: (a) density-gradient-driven stratified <span class="hlt">flow</span> is a much more rapid mechanism (at least one order of magnitude) for moving <span class="hlt">air</span> into the reactor vessel lower plenum than diffusion, and consequently, (b) the diffusion dominated phase begins with a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22105943','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22105943"><span>Heat transfer deterioration in tubes caused by bulk <span class="hlt">flow</span> acceleration <span class="hlt">due</span> to thermal and frictional influences</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jackson, J. D.</p> <p>2012-07-01</p> <p>Severe deterioration of forced convection heat transfer can be encountered with compressible fluids <span class="hlt">flowing</span> through strongly heated tubes of relatively small bore as the <span class="hlt">flow</span> accelerates and turbulence is reduced because of the fluid density falling (as the temperature rises and the pressure falls <span class="hlt">due</span> to thermal and frictional influence). The model presented here throws new light on how the dependence of density on both temperature and pressure can affect turbulence and heat transfer and it explains why the empirical equations currently available for calculating effectiveness of forced convection heat transfer under conditions of strong non-uniformity of fluid properties sometimes fail to reproduce observed behaviour. It provides a criterion for establishing the conditions under which such deterioration of heat transfer might be encountered and enables heat transfer coefficients to be determined when such deterioration occurs. The analysis presented here is for a gaseous fluid at normal pressure subjected strong non-uniformity of fluid properties by the application of large temperature differences. Thus the model leads to equations which describe deterioration of heat transfer in terms of familiar parameters such as Mach number, Reynolds number and Prandtl number. It is applicable to thermal power plant systems such as rocket engines, gas turbines and high temperature gas-cooled nuclear reactors. However, the ideas involved apply equally well to fluids at supercritical pressure. Impairment of heat transfer under such conditions has become a matter of growing interest with the active consideration now being given to advanced water-cooled nuclear reactors designed to operate at pressures above the critical value. (authors)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..167a2009Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..167a2009Z"><span>Experimental study on heat transfer performance of aluminium foam parallel-<span class="hlt">flow</span> condenser in <span class="hlt">air</span> conditioner</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, X.; Wan, Z. M.; Chang, H. W.; Wang, Y. D.</p> <p>2017-01-01</p> <p>Open cell aluminium foam was used in parallel-<span class="hlt">flow</span> condenser in <span class="hlt">air</span> conditioner, and two condensers with different pore density were fabricated. The experimental study was conducted on the heat transfer performance and temperature distribution. The experimental results show that both of the heat transfer load and <span class="hlt">air</span> pressure drop increase with the increase of pore density, <span class="hlt">air</span> velocity is 2.5m/s, the heat transfer capacities of the condenser with 10PPI and 8PPI are 4.786kw and 3.344kW respectively. Along the <span class="hlt">flow</span> direction of refrigerant, the outlet temperatures of refrigerant drop with the rise of <span class="hlt">air</span> velocity when the inlet temperature is constant. The outlet temperature of the refrigerant decreases with the increase of pore density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDE32005C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDE32005C"><span>Drainage of the <span class="hlt">air</span> film during drop impact on <span class="hlt">flowing</span> liquid films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Che, Zhizhao; Matar, Omar</p> <p>2015-11-01</p> <p>Immediately upon the impact of a droplet on a liquid or a solid, a thin <span class="hlt">air</span> cushion is formed by trapping <span class="hlt">air</span> beneath the droplet. The drainage of the <span class="hlt">air</span> film is critical in determining the eventual outcome of the impact. Here we propose a model to study the drainage of the gas film between a droplet and a <span class="hlt">flowing</span> liquid film. The effects of a wide range of parameters influencing the drainage process are studied, such as the fluid viscosities, the surface tension, the velocity of the droplet, the velocity of the liquid film. The results show that the tangential movement of the liquid film can delay the drainage of the <span class="hlt">air</span> film and promote the bouncing of droplets. This confirms our previous experimental results, which show that during the impact of droplets on <span class="hlt">flow</span> liquid films, the probability of bouncing increases with the Reynolds number of the liquid film. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H43E1498D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H43E1498D"><span>Effect of Periodic Surface <span class="hlt">Air</span> Temperature Variations on Subsurface Thermal Structure with Vertical Fluid <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D, R. V.; Ravi, M.; Srivastava, K.</p> <p>2016-12-01</p> <p>The influence of climate change on near subsurface temperatures is an important research topic for global change impact assessment at the regional scale. The varying temperature of the <span class="hlt">air</span> over the surface in long term will disturb subsurface thermal structure. Groundwater <span class="hlt">flow</span> is another important process which perturbs the thermal distribution into the subsurface. To investigate the effect of periodic <span class="hlt">air</span> temperature on nonisothermal subsurface, one dimensional transient heat conduction-advection equation is solved numerically using finite element method. Thermal response of subsurface for periodic variations in surface <span class="hlt">air</span> temperature (SAT) with robin type boundary condition on the surface with vertical ground water <span class="hlt">flow</span> are calculated and the amplitude attenuation of propagation of surface temperature information in the subsurface for different scenarios of advection and convective coefficient are discussed briefly. The results show the coupled response of trigonometric variation in <span class="hlt">air</span> temperature with surface temperatures along with ground water velocity has significant implications for the effects of climate change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009CNSNS..14.3599P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009CNSNS..14.3599P"><span>Heat and mass transfer in liquid desiccant <span class="hlt">air</span>-conditioning process at low <span class="hlt">flow</span> conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peng, S. W.; Pan, Z. M.</p> <p>2009-09-01</p> <p>This paper investigates the transient heat and mass transfer in liquid desiccant <span class="hlt">air</span>-conditioning process at low <span class="hlt">flow</span> conditions. Using local volumetric average approach, one-dimensional non-equilibrium heat and mass transfer models are developed to describe the humid <span class="hlt">air</span> and liquid desiccant interaction at counter <span class="hlt">flow</span> configuration. Using triethylene glycol solution as desiccant, some experimental studies are completed. Experimental results are used to justify the numerical models. Numerical results are then obtained to demonstrate process characteristics. The models include a transient desiccant <span class="hlt">flow</span> model for initial liquid desiccant building-up process, empirical wetted specific surface ratio for mass transfer, and heat and mass transfer coefficients. The objective of this research is to develop a process analytical tool for liquid desiccant <span class="hlt">air</span>-conditioner design.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21350393','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21350393"><span>Experimental study on corrugated cross-<span class="hlt">flow</span> <span class="hlt">air</span>-cooled plate heat exchangers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, Minsung; Baik, Young-Jin; Park, Seong-Ryong; Ra, Ho-Sang; Lim, Hyug</p> <p>2010-11-15</p> <p>Experimental study on cross-<span class="hlt">flow</span> <span class="hlt">air</span>-cooled plate heat exchangers (PHEs) was performed. The two prototype PHEs were manufactured in a stack of single-wave plates and double-wave plates in parallel. Cooling <span class="hlt">air</span> <span class="hlt">flows</span> through the PHEs in a crosswise direction against internal cooling water. The heat exchanger aims to substitute open-loop cooling towers with closed-loop water circulation, which guarantees cleanliness and compactness. In this study, the prototype PHEs were tested in a laboratory scale experiments. From the tests, double-wave PHE shows approximately 50% enhanced heat transfer performance compared to single-wave PHE. However, double-wave PHE costs 30% additional pressure drop. For commercialization, a wide channel design for <span class="hlt">air</span> <span class="hlt">flow</span> would be essential for reliable performance. (author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPJP..130..225S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPJP..130..225S"><span>Fluid <span class="hlt">flow</span> and heat transfer in an <span class="hlt">air</span>-to-water double-pipe heat exchanger</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheikholeslami, M.; Gorji-Bandpy, M.; Ganji, D. D.</p> <p>2015-11-01</p> <p>This paper reports experimental and numerical investigations on <span class="hlt">flow</span> and heat transfer in an <span class="hlt">air</span>-to-water double-pipe heat exchanger. The working fluids are <span class="hlt">air</span> and water. To achieve fully developed conditions, the heat exchanger was built with additional lengths before and after the test section. The inner and outer tube was made from copper and Plexiglas, respectively. The experiments are conducted in the range of <span class="hlt">air</span> <span class="hlt">flow</span> Reynolds number for various cases with different water <span class="hlt">flow</span> rate and water inlet temperature. Correlations for the Nusselt number and friction factor are presented according to experimental data. Also the commercial code ANSYS 15 is used for numerical simulation. Results show that the Nusselt number is an increasing function of Reynolds number and Prandtl number which are calculated at bulk temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930090895','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930090895"><span>Improving the performance of a compression ignition engine by directing <span class="hlt">flow</span> of inlet <span class="hlt">air</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kemper, Carlton</p> <p>1946-01-01</p> <p>The object of this report is to present the results of tests performed by the National Advisory Committee for Aeronautics to determine the effect on engine performance of directing the <span class="hlt">flow</span> of the inlet <span class="hlt">air</span> to a 5-inch by 7-inch cylinder, solid injection, compression ignition engine, After a few preliminary tests, comparative runs were made at a speed of 1500 r.p.m. with and without directed <span class="hlt">air</span> <span class="hlt">flow</span>. It was found that directing the <span class="hlt">flow</span> of the inlet <span class="hlt">air</span> toward the fuel injection valve gave steadier engine operation, and an appreciable increase in power, and decreased fuel consumption. The results indicate the possibility of improving the performance of a given type of combustion chamber without changing its shape and with no change in valve timing. They would also seem to prove that directional turbulence, set up before the inlet valve of a four-stroke cycle engine, continues in the engine cylinder throughout the compression stroke.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8572E..15C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8572E..15C"><span>Using color intensity projections to visualize <span class="hlt">air</span> <span class="hlt">flow</span> in operating theaters with the goal of reducing infections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cover, Keith S.; van Asperen, Niek; de Jong, Joost; Verdaasdonk, Rudolf M.</p> <p>2013-03-01</p> <p>Infection following neurosurgery is all too common. One possible source of infection is the transportation of dust and other contaminates into the open wound by airflow within the operating theatre. While many modern operating theatres have a filtered, uniform and gentle <span class="hlt">flow</span> of <span class="hlt">air</span> cascading down over the operating table from a large area fan in the ceiling, many obstacles might introduce turbulence into the laminar <span class="hlt">flow</span> including lights, equipment and personal. Schlieren imaging - which is sensitive to small disturbances in the laminar <span class="hlt">flow</span> such as breathing and turbulence caused by <span class="hlt">air</span> warmed by a hand at body temperature - was used to image the <span class="hlt">air</span> <span class="hlt">flow</span> <span class="hlt">due</span> to activities in an operating theatre. Color intensity projections (CIPs) were employed to reduce the workload of analyzing the large amount of video data. CIPs - which has been applied to images in angiography, 4D CT, nuclear medicine and astronomy - summarizes the changes over many gray scale images in a single color image in a way which most interpreters find intuitive. CIPs uses the hue, saturation and brightness of the color image to encode the summary. Imaging in an operating theatre showed substantial disruptions to the airflow <span class="hlt">due</span> to equipment such as the lighting. When these disruptions are combined with such minor factors as heat from the hand, reversal of the preferred airflow patterns can occur. These reversals of preferred airflow patterns have the potential to transport contaminates into the open wound. Further study is required to understand both the frequency of the reversed airflow patterns and the impact they may have on infection rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24355413','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24355413"><span>Risk assessment for cardiovascular and respiratory mortality <span class="hlt">due</span> to <span class="hlt">air</span> pollution and synoptic meteorology in 10 Canadian cities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vanos, Jennifer K; Hebbern, Christopher; Cakmak, Sabit</p> <p>2014-02-01</p> <p>Synoptic weather and ambient <span class="hlt">air</span> quality synergistically influence human health. We report the relative risk of mortality from all non-accidental, respiratory-, and cardiovascular-related causes, associated with exposure to four <span class="hlt">air</span> pollutants, by weather type and season, in 10 major Canadian cities for 1981 through 1999. We conducted this multi-city time-series study using Poisson generalized linear models stratified by season and each of six distinctive synoptic weather types. Statistically significant relationships of mortality <span class="hlt">due</span> to short-term exposure to carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone were found, with significant modifications of risk by weather type, season, and mortality cause. In total, 61% of the respiratory-related mortality relative risk estimates were significantly higher than for cardiovascular-related mortality. The combined effect of weather and <span class="hlt">air</span> pollution is greatest when tropical-type weather is present in the spring or summer. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1361338','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1361338"><span>Neutron imaging of diabatic two-phase <span class="hlt">flows</span> relevant to <span class="hlt">air</span> conditioning</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Geoghegan, Patrick J; Sharma, Vishaldeep</p> <p>2017-01-01</p> <p>The design of the evaporator of an <span class="hlt">air</span> conditioning system relies heavily on heat transfer coefficients and pressure drop correlations that predominantly involve an estimate of the changing void fraction and the underlying two-phase <span class="hlt">flow</span> regime. These correlations dictate whether the resulting heat exchanger is oversized or not and the amount of refrigerant charge necessary to operate. The latter is particularly important when dealing with flammable or high GWP refrigerants. Traditional techniques to measure the void fraction and visualize the <span class="hlt">flow</span> are either invasive to the <span class="hlt">flow</span> or occur downstream of the evaporator, where some of the <span class="hlt">flow</span> distribution will have changed. Neutron imaging has the potential to visualize two-phase <span class="hlt">flow</span> in-situ where an aluminium heat exchanger structure becomes essentially transparent to the penetrating neutrons. The subatomic particles are attenuated by the passing refrigerant <span class="hlt">flow</span>. The resulting image may be directly related to the void fraction and the overall picture provides a clear insight into the <span class="hlt">flow</span> regime present. This work presents neutron images of the refrigerant Isopentane as it passes through the <span class="hlt">flow</span> channels of an aluminium evaporator at flowrates relevant to <span class="hlt">air</span> conditioning. The <span class="hlt">flow</span> in a 4mm square macro channel is compared to that in a 250 m by 750 m rectangular microchannel in terms of void fraction and regime. All neutron imaging experiments were conducted at the High Flux Isotope Reactor, an Oak Ridge National Laboratory facility</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16688352','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16688352"><span>Elevated concentrations of endotoxin in indoor <span class="hlt">air</span> <span class="hlt">due</span> to cigarette smoking.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sebastian, Aleksandra; Pehrson, Christina; Larsson, Lennart</p> <p>2006-05-01</p> <p>Exposure to environmental tobacco smoke (ETS) is an important worldwide public health issue. The present study demonstrates that cigarette smoke can be a major source of endotoxin (lipopolysaccharide, LPS) in indoor environments. Gas-chromatography/mass-spectrometry was used to determine 3-hydroxy fatty acids as markers of endotoxin in <span class="hlt">air</span>-borne house dust in homes of smokers and non-smokers. <span class="hlt">Air</span> concentrations of endotoxin were 4-63 times higher in rooms of smoking students than in identical rooms of non-smoking students. The fact that cigarette smoke contains large amounts of endotoxin may partly explain the high prevalence of respiratory disorders among smokers and may also draw attention to a hitherto neglected risk factor of ETS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27635468','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27635468"><span>Rapid Induction of Therapeutic Hypothermia Using Transnasal High <span class="hlt">Flow</span> Dry <span class="hlt">Air</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chava, Raghuram; Zviman, Menekhem; Raghavan, Madhavan Srinivas; Halperin, Henry; Maqbool, Farhan; Geocadin, Romergryko; Quinones-Hinojosa, Alfredo; Kolandaivelu, Aravindan; Rosen, Benjamin A; Tandri, Harikrishna</p> <p>2017-03-01</p> <p>Early induction of therapeutic hypothermia (TH) is recommended in out-of-hospital cardiac arrest (CA); however, currently no reliable methods exist to initiate cooling. We investigated the effect of high <span class="hlt">flow</span> transnasal dry <span class="hlt">air</span> on brain and body temperatures in adult porcine animals. Adult porcine animals (n = 23) under general anesthesia were subject to high <span class="hlt">flow</span> of transnasal dry <span class="hlt">air</span>. Mouth was kept open to create a unidirectional airflow, in through the nostrils and out through the mouth. Brain, internal jugular, and aortic temperatures were recorded. The effect of varying airflow rate and the <span class="hlt">air</span> humidity (0% or 100%) on the temperature profiles were recorded. The degree of brain cooling was measured as the differential temperature from baseline. A 10-minute exposure of high <span class="hlt">flow</span> dry <span class="hlt">air</span> caused rapid cooling of brain and gradual cooling of the jugular and the aortic temperatures in all animals. The degree of brain cooling was <span class="hlt">flow</span> dependent and significantly higher at higher airflow rates (0.8°C ± 0.3°C, 1.03°C ± 0.6°C, and 1.3°C ± 0.7°C for 20, 40, and 80 L, respectively, p < 0.05 for all comparisons). <span class="hlt">Air</span> temperature had minimal effect on the brain cooling over 10 minutes with similar decrease in temperature at 4°C and 30°C. At a constant <span class="hlt">flow</span> rate (40 LPM) and temperature, the degree of cooling over 10 minutes during dry <span class="hlt">air</span> exposure was significantly higher compared to humid <span class="hlt">air</span> (100% saturation) (1.22°C ± 0.35°C vs. 0.21°C ± 0.12°C, p < 0.001). High <span class="hlt">flow</span> transnasal dry <span class="hlt">air</span> causes <span class="hlt">flow</span> dependent cooling of the brain and the core temperatures in intubated porcine animals. The mechanism of cooling appears to be evaporation of nasal mucus as cooling is mitigated by humidifying the <span class="hlt">air</span>. This mechanism may be exploited to initiate TH in CA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/152940','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/152940"><span>Effects of saline-water <span class="hlt">flow</span> rate and <span class="hlt">air</span> speed on leakage current in RTV coatings</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, S.H.; Hackam, R.</p> <p>1995-10-01</p> <p>Room temperature vulcanizing (RTV) silicone rubber is increasingly being used to coat porcelain and glass insulators in order to improve their electrical performance in the presence of pollution and moisture. A study of the dependence of leakage current, pulse current count and total charge <span class="hlt">flowing</span> across the surface of RTV on the <span class="hlt">flow</span> rate of the saline water and on the compressed <span class="hlt">air</span> pressure used to create the salt-fog is reported. The fog was directed at the insulating rods either from one or two sides. The RTV was fabricated from polydimethylsiloxane polymer, a filler of alumina trihydrate (ATH), a polymerization catalyst and fumed silica reinforcer, all dispersed in 1,1,1-trichloroethane solvent. The saline water <span class="hlt">flow</span> rate was varied in the range 0.4 to 2.0 l/min. The compressed <span class="hlt">air</span> pressure at the input of the fog nozzles was varied from 0.20 to 0.63 MPa. The <span class="hlt">air</span> speed at the surface of the insulating rods was found to depend linearly on the <span class="hlt">air</span> pressure measured at the inlet to the nozzles and varied in the range 3 to 14 km/hr. The leakage current increased with increasing <span class="hlt">flow</span> rate and increasing <span class="hlt">air</span> speed. This is attributed to the increased loss of hydrophobicity with a larger quantity of saline fog and a larger impact velocities of fog droplets interacting with the surface of the RTV coating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26233015','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26233015"><span>Laryngeal <span class="hlt">flow</span> <span class="hlt">due</span> to longitudinal sweeping motion of the vocal folds and its contribution to auto-oscillation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boutin, Henri; Smith, John; Wolfe, Joe</p> <p>2015-07-01</p> <p>Analysis of published depth-kymography data [George, de Mul, Qiu, Rakhorst, and Schutte (2008). Phys. Med. Biol. 53, 2667-2675] shows that, for the subject studied, the <span class="hlt">flow</span> <span class="hlt">due</span> to the longitudinal sweeping motion of the vocal folds contributes several percent of a typical acoustic <span class="hlt">flow</span> at the larynx. This sweeping <span class="hlt">flow</span> is a maximum when the glottis is closed. This observation suggests that assumption of zero laryngeal <span class="hlt">flow</span> during the closed phase as a criterion when determining parameters in inverse filtering should be used with caution. Further, these data suggest that the swinging motion contributes work to overcome mechanical losses and thus to assist auto-oscillation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACPD...13.7737L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACPD...13.7737L"><span>Model calculated global, regional and megacity premature mortality <span class="hlt">due</span> to <span class="hlt">air</span> pollution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lelieveld, J.; Barlas, C.; Giannadaki, D.; Pozzer, A.</p> <p>2013-03-01</p> <p><span class="hlt">Air</span> pollution by fine particulate matter (PM2.5) and ozone (O3) has increased strongly with industrialization and urbanization. We estimated the premature mortality rates and the years of human life lost (YLL) caused by anthropogenic PM2.5 and O3 in 2005 for epidemiological regions defined by the World Health Organization. We carried out high-resolution global model calculations to resolve urban and industrial regions in greater detail compared to previous work. We applied a health impact function to estimate premature mortality for people of 30 yr and older, using parameters derived from epidemiological cohort studies. Our results suggest that especially in large countries with extensive suburban and rural populations, <span class="hlt">air</span> pollution-induced mortality rates have previously been underestimated. We calculate a global respiratory mortality of about 773 thousand yr-1 (YLL ≈ 5.2 million yr-1), 186 thousand yr-1 by lung cancer (YLL ≈ 1.7 million yr-1) and 2.0 million yr-1 by cardiovascular disease (YLL ≈ 14.3 million yr-1). The global mean per capita mortality caused by <span class="hlt">air</span> pollution is about 0.1 % yr-1. The highest premature mortality rates are found in the Southeast Asia and Western Pacific regions (about 25% and 46% of the global rate, respectively) where more than a dozen of the most highly polluted megacities are located.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25017960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25017960"><span>Coal mining activities change plant community structure <span class="hlt">due</span> to <span class="hlt">air</span> pollution and soil degradation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth</p> <p>2014-10-01</p> <p>The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. <span class="hlt">Air</span> monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient <span class="hlt">air</span>, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to <span class="hlt">air</span> pollution and altered soil characteristics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930091664','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930091664"><span>Fuel Spray and Flame Formation in a Compression-Ignition Engine Employing <span class="hlt">Air</span> <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rothrock, A M; Waldron, C D</p> <p>1937-01-01</p> <p>The effects of <span class="hlt">air</span> <span class="hlt">flow</span> on fuel spray and flame formation in a high-speed compression-ignition engine have been investigated by means of the NACA combustion apparatus. The process was studied by examining high-speed motion pictures taken at the rate of 2,200 frames a second. The combustion chamber was of the flat-disk type used in previous experiments with this apparatus. The <span class="hlt">air</span> <span class="hlt">flow</span> was produced by a rectangular displacer mounted on top of the engine piston. Three fuel-injection nozzles were tested: a 0.020-inch single-orifice nozzle, a 6-orifice nozzle, and a slit nozzle. The <span class="hlt">air</span> velocity within the combustion chamber was estimated to reach a value of 425 feet a second. The results show that in no case was the form of the fuel spray completely destroyed by the <span class="hlt">air</span> jet although in some cases the direction of the spray was changed and the spray envelope was carried away by the moving <span class="hlt">air</span>. The distribution of the fuel in the combustion chamber of a compression-ignition engine can be regulated to some extent by the design of the combustion chamber, by the design of the fuel-injection nozzle, and by the use of <span class="hlt">air</span> <span class="hlt">flow</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JPhCS.166a2017C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JPhCS.166a2017C"><span>Transition to chaos of a vertical collapsible tube conveying <span class="hlt">air</span> <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castillo Flores, F.; Cros, A.</p> <p>2009-05-01</p> <p>"Sky dancers", the large collapsible tubes used as advertising, are studied in this work through a simple experimental device. Our study is devoted to the nonlinear dynamics of this system and to its transition to chaos. Firstly, we have shown that after a collapse occurs, the <span class="hlt">air</span> fills the tube at a different speed rate from the <span class="hlt">flow</span> velocity. Secondly, the temporal intermittency is studied as the <span class="hlt">flow</span> rate is increased. A statistical analysis shows that the chaotic times maintain roughly the same value by increasing <span class="hlt">air</span> speed. On the other hand, laminar times become shorter, until the system reaches a completely chaotic state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2225990','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2225990"><span>Responses of the Rat Olfactory Epithelium to Retronasal <span class="hlt">Air</span> <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Scott, John W.; Acevedo, Humberto P.; Sherrill, Lisa; Phan, Maggie</p> <p>2008-01-01</p> <p>Responses of the rat olfactory epithelium were assessed with the electroolfactogram while odorants were presented to the external nares with an artificial sniff or to the internal nares by positive pressure. A series of seven odorants that varied from very polar, hydrophilic odorants to very non-polar, hydrophobic odorants were used. While the polar odorants activated the dorsal olfactory epithelium when presented by the external nares (orthonasal presentation), they were not effective when forced through the nasal cavity from the internal nares (retronasal presentation). However, the non-polar odorants were effective in both stimulus modes. These results were independent of stimulus concentration or of humidity of the carrier <span class="hlt">air</span>. Similar results were obtained with multiunit recording from olfactory bulb. These results help to explain why human investigations often report differences in the sensation or ability to discriminate odorants presented orthonasally vs. retronasally. The results also strongly support the importance of odorant sorption in normal olfactory processes. PMID:17215498</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3710649','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3710649"><span>Experimental Studies of Active and Passive <span class="hlt">Flow</span> Control Techniques Applied in a Twin <span class="hlt">Air</span>-Intake</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Joshi, Shrey; Jindal, Aman; Maurya, Shivam P.; Jain, Anuj</p> <p>2013-01-01</p> <p>The <span class="hlt">flow</span> control in twin <span class="hlt">air</span>-intakes is necessary to improve the performance characteristics, since the <span class="hlt">flow</span> traveling through curved and diffused paths becomes complex, especially after merging. The paper presents a comparison between two well-known techniques of <span class="hlt">flow</span> control: active and passive. It presents an effective design of a vortex generator jet (VGJ) and a vane-type passive vortex generator (VG) and uses them in twin <span class="hlt">air</span>-intake duct in different combinations to establish their effectiveness in improving the performance characteristics. The VGJ is designed to insert <span class="hlt">flow</span> from side wall at pitch angle of 90 degrees and 45 degrees. Corotating (parallel) and counterrotating (V-shape) are the configuration of vane type VG. It is observed that VGJ has the potential to change the <span class="hlt">flow</span> pattern drastically as compared to vane-type VG. While the VGJ is directed perpendicular to the side walls of the <span class="hlt">air</span>-intake at a pitch angle of 90 degree, static pressure recovery is increased by 7.8% and total pressure loss is reduced by 40.7%, which is the best among all other cases tested for VGJ. For bigger-sized VG attached to the side walls of the <span class="hlt">air</span>-intake, static pressure recovery is increased by 5.3%, but total pressure loss is reduced by only 4.5% as compared to all other cases of VG. PMID:23935422</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A53L3364K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A53L3364K"><span>Numerical Study on a Detailed <span class="hlt">Air</span> <span class="hlt">Flows</span> in an Urban Area Using a CFD model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwon, A.</p> <p>2014-12-01</p> <p>In this study, detailed <span class="hlt">air</span> <span class="hlt">flows</span> in an urban area were analyzed using a computational fluid dynamics (CFD) model. For this model buildings used as the surface boundary in the model were constructed using Los Angeles Region Imagery Acquisition Consortium 2 Geographic Information System (LARIAC2 GIS) data. Three target areas centered at the cross roads of Broadway & 7th St., Olive & 12th St., and Wilshire blvd. & Carondelet, Los Angeles, California were considered. The size of each numerical domain is 400 m, 400 m, and 200 m in the x‒, y‒, and z‒directions, respectively. The grid sizes in the x‒, y‒, and z‒directions are 2 m, 2 m, and 2 m, respectively. Based on the inflow wind data provided by California <span class="hlt">Air</span> Resources Board, detailed <span class="hlt">flow</span> characteristics were investigated for each target area. Descending <span class="hlt">air</span> <span class="hlt">flow</span> were developed at the leeward area of tall building and ascending <span class="hlt">air</span> current were occurred on the windward area of tall building. Vertically rotating vortices were formed in spaces between buildings, so-called, street canyons and horizontally rotating vortices appeared near cross roads. When <span class="hlt">flows</span> came into narrow street canyon from wide street canyon, channeling effects appeared and <span class="hlt">flow</span> speed increased for satisfying mass continuity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840025341','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840025341"><span>An experimental investigation of gas jets in confined swirling <span class="hlt">air</span> <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mongia, H.; Ahmed, S. A.; Mongia, H. C.</p> <p>1984-01-01</p> <p>The fluid dynamics of jets in confined swirling <span class="hlt">flows</span> which is of importance to designers of turbine combustors and solid fuel ramjets used to power missiles fired from cannons were examined. The fluid dynamics of gas jets of different densities in confined swirling <span class="hlt">flows</span> were investigated. Mean velocity and turbulence measurements are made with a one color, one component laser velocimeter operating in the forward scatter mode. It is shown that jets in confined <span class="hlt">flow</span> with large area ratio are highly dissipative which results in both <span class="hlt">air</span> and helium/<span class="hlt">air</span> jet centerline velocity decays. For <span class="hlt">air</span> jets, the jet like behavior in the tube center disappears at about 20 diameters downstream of the jet exit. This phenomenon is independent of the initial jet velocity. The turbulence field at this point also decays to that of the background swirling <span class="hlt">flow</span>. A jet like behavior in the tube center is noticed even at 40 diameters for the helium/<span class="hlt">air</span> jets. The subsequent <span class="hlt">flow</span> and turbulence field depend highly on the initial jet velocity. The jets are fully turbulent, and the cause of this difference in behavior is attributed to the combined action swirl and density difference. This observation can have significant impact on the design of turbine combustors and solid fuel ramjets subject to spin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A21A0104L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A21A0104L"><span>Multimodel estimates of premature human mortality <span class="hlt">due</span> to intercontinental transport of <span class="hlt">air</span> pollution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, C.; Silva, R.; West, J. J.; Sudo, K.; Lund, M. T.; Emmons, L. K.; Takemura, T.; Bian, H.</p> <p>2015-12-01</p> <p>Numerous modeling studies indicate that emissions from one continent influence <span class="hlt">air</span> quality over others. Reducing <span class="hlt">air</span> pollutant emissions from one continent can therefore benefit <span class="hlt">air</span> quality and health on multiple continents. Here, we estimate the impacts of the intercontinental transport of ozone (O3) and fine particulate matter (PM2.5) on premature human mortality by using an ensemble of global chemical transport models coordinated by the Task Force on Hemispheric Transport of <span class="hlt">Air</span> Pollution (TF HTAP). We use simulations of 20% reductions of all anthropogenic emissions from 13 regions (North America, Central America, South America, Europe, Northern Africa, Sub-Saharan Africa, Former Soviet Union, Middle East, East Asia, South Asia, South East Asia, Central Asia, and Australia) to calculate their impact on premature mortality within each region and elsewhere in the world. To better understand the impact of potential control strategies, we also analyze premature mortality for global 20% perturbations from five sectors individually: power and industry, ground transport, forest and savannah fires, residential, and others (shipping, aviation, and agriculture). Following previous studies, premature human mortality resulting from each perturbation scenario is calculated using a health impact function based on a log-linear model for O3 and an integrated exposure response model for PM2.5 to estimate relative risk. The spatial distribution of the exposed population (adults aged 25 and over) is obtained from the LandScan 2011 Global Population Dataset. Baseline mortality rates for chronic respiratory disease, ischemic heart disease, cerebrovascular disease, chronic obstructive pulmonary disease, and lung cancer are estimated from the GBD 2010 country-level mortality dataset for the exposed population. Model results are regridded from each model's original grid to a common 0.5°x0.5° grid used to estimate mortality. We perform uncertainty analysis and evaluate the sensitivity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JFM...435...25C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JFM...435...25C"><span><span class="hlt">Flow</span> structures and particle deposition patterns in double-bifurcation airway models. Part 1. <span class="hlt">Air</span> <span class="hlt">flow</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Comer, J. K.; Kleinstreuer, C.; Zhang, Z.</p> <p>2001-05-01</p> <p>The understanding and quantitative assessment of <span class="hlt">air</span> <span class="hlt">flow</span> fields and local micron-particle wall concentrations in tracheobronchial airways are very important for estimating the health risks of inhaled particulate pollutants, developing algebraic transfer functions of global lung deposition models used in dose-response analyses, and/or determining proper drug-aerosol delivery to target sites in the lung. In this paper (Part 1) the theory, model geometries, and <span class="hlt">air</span> <span class="hlt">flow</span> results are provided. In a companion paper (Part 2, Comer et al. 2001), the history of particle deposition patterns and comparisons with measured data sets are reported. Decoupling of the naturally dilute particle suspension makes it feasible to present the results in two parts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H13E1420Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H13E1420Y"><span>Effects of entrapped <span class="hlt">air</span> in a closed soil pipe on the soil pipe <span class="hlt">flow</span> during a rainfall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamasaki, T.; Imoto, H.; Hamamoto, S.; Nishimura, T.</p> <p>2016-12-01</p> <p>Soil pipes, continuous macropores parallel to the slope, are considered to have an important role in hillslope hydrological processes. However, knowledge of water <span class="hlt">flow</span> in the closed soil pipe is still limited <span class="hlt">due</span> to the lack of the nondestructive observations. The objective of this study is to clarify water <span class="hlt">flow</span> dynamics in the closed soil pipe directly by the laboratory experiment using a soil box with an artificial soil pipe. An acrylic plastic pipe, 7 mm inner diameter, 10 mm outer diameter, and 40 cm long, was used as an artificial soil pipe. Drain holes were evenly opened on the pipe wall and covered by nylon mesh. Soil pipe was connected to a pressure transducer to measure <span class="hlt">air</span> pressure in the pipe. Two-needle electrodes were set inside the pipe to detect a pipe <span class="hlt">flow</span>. Acrylic rectangular box, 60 cm long, 4 cm wide and 35 cm high, was filled with Toyoura sand with 3 % mass water content to a thickness of 30 cm. Drainage holes were opened at the downward outlet of the box. Artificial soil pipe was buried at center of soil box and 2.5 cm high from the base of the box. After packing the sand, soil box was inclined, and then artificial rainfall, 40-250 mm h-1, was applied. During the experiments, outflow rate and soil water pressure were measured. In the slope of 10°, soil pipe <span class="hlt">flow</span> was not observed under either rainfall intensities, though groundwater table rose above the soil pipe. Increase in <span class="hlt">air</span> pressure in the soil pipe started prior to the water saturation of soil around the soil pipe. This suggested that entrapped <span class="hlt">air</span> in the soil pipe prevented water intrusion into the soil pipe. In the slope of 20°, soil pipe <span class="hlt">flow</span> started when soil around the lower end of the soil pipe was saturated, but steady-state groundwater table was similar to that under no pipe condition. Release of the <span class="hlt">air</span> in the soil pipe greatly decreased the groundwater level, indicating that even after the soil pipe <span class="hlt">flow</span> started, entrapped <span class="hlt">air</span> restricted the drainage through the soil pipe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28059248','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28059248"><span>Tomographic optical emission spectroscopy of a high enthalpy <span class="hlt">air</span> plasma <span class="hlt">flow</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hermann, Tobias; Löhle, Stefan; Fasoulas, Stefanos; Andrianatos, Andreas</p> <p>2016-12-20</p> <p>A method is presented allowing for locally resolved emission spectroscopy using a tomographic setup. The approach presented in this work is applied to a high enthalpy <span class="hlt">air</span> plasma <span class="hlt">flow</span>. The resulting data sets allow for a three-dimensional (3D) representation of the non-symmetric <span class="hlt">flow</span> field using photographs of the test section and 2D representation of the spectrally resolved radiance of the <span class="hlt">flow</span> field. An analysis of different exposure times shows that transient fluctuations of the plasma can result in substantial asymmetry that approaches symmetry only for longer exposure times when the temporal averaging of the emission is significant. The spectral data allows the analysis of species selective excitation and emission. A non-equilibrium between atomic and molecular excitation temperatures is concluded for the investigated <span class="hlt">air</span> plasma <span class="hlt">flow</span> field. The spatial distribution of atomic electronic excitation temperatures are close to rotational symmetry while molecular rotational and vibrational temperatures exhibit asymmetric behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ntfm.book..288L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ntfm.book..288L"><span>Numerical Simulation of Aerodynamic Heating Reduction <span class="hlt">due</span> to Opposing Jet in Supersonic <span class="hlt">Flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, H. Y.; Eri, Q. T.</p> <p></p> <p>In supersonic flight, severe aerodynamic heating takes place at the nose of blunt body and causes ablation. Accurate prediction of aerodynamic heating and construction of proper thermal protection system are required. The numerical study on a reduction of aerodynamic heating by opposing jet has been conducted. <span class="hlt">Flow</span> field around a hemisphere model is calculated in supersonic free stream of Mach number 3.98 and the coolant gas is injected through the nozzle at the nose the model. CFD method was Finite Volume Method for time integration be used, axisymmetric full Navier-Stokes equations were applied as governing equations and k-ɛturbulence model is used. Numerical simulation demonstrated, compared with no jet, the reduction of aerodynamic heating <span class="hlt">due</span> to opposing jet was to be proved quite effective at the nose of blunt body. Parameters in this numerical study insofar, as the pressure ratio is increased, caused the wall pressure and heat flux decrease, and recirculation region size largen. effective reduction of the aerodynamic heating remarkably. As the opposing nozzle diameter ratio was decreased, the pressure and heat flux increased, and recirculation region size lessening, the effect of reduction aerodynamic heating was reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ASPC..390..359L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ASPC..390..359L"><span>Galactic Disk Warps <span class="hlt">due</span> to Intergalactic Accretion <span class="hlt">Flows</span> onto the Disk</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>López-Corredoira, M.; Betancort-Rijo, J.; Beckman, J. E.</p> <p>2008-06-01</p> <p>The accretion of the intergalactic medium onto the gaseous disc is used to explain the generation of galactic warps. A cup-shaped distortion is expected, <span class="hlt">due</span> to the transmission of the linear momentum; but, this effect is small for most incident inflow angles and the predominant effect turns out to be the transmission of angular momentum, i.e. a torque giving an integral-sign shaped warp. The torque produced by a <span class="hlt">flow</span> of velocity ˜ 100 km/s and baryon density ˜ 10-25 kg/m3, which is within the possible values for the intergalactic medium, is enough to generate the observed warps and this mechanism offers quite a plausible explanation. The inferred rate of infall of matter, ˜ 1 M⊙/yr, to the Galactic disc that this theory predicts agrees with the quantitative predictions of chemical evolution resolving key issues, notably the G-dwarf problem. Sánchez-Salcedo (2006) suggests that this mechanism is not plausible because it would produce a dependence of the scaleheight of the disc with the Galactocentric azimuth in the outer disc, but rather than being an objection this is another argument in favour of the mechanism because this dependence is actually observed in our Galaxy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=298341','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=298341"><span>When <span class="hlt">air</span> really matters: <span class="hlt">Flow</span> depth relationships for stepped spillways</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>With changing demographics in the vicinity of aging embankment dams, hazard creep, a change in classification from low to significant or high, can become problematic and limit rehabilitation options. The most common deficiency for embankment dams <span class="hlt">due</span> to hazard creep is inadequate spillway capacity....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18850978','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18850978"><span>Slip-length measurement of confined <span class="hlt">air</span> <span class="hlt">flow</span> using dynamic atomic force microscopy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maali, Abdelhamid; Bhushan, Bharat</p> <p>2008-08-01</p> <p>We present an experimental measurement of the slip length of <span class="hlt">air</span> <span class="hlt">flow</span> close to solid surfaces using an atomic force microscope (AFM) in dynamic mode. The <span class="hlt">air</span> was confined between a glass surface and a spherical glass particle glued to an AFM cantilever. The Knudsen number was varied continuously over three decades by varying the distance between the two surfaces. Our results show that the effect of confining the <span class="hlt">air</span> is purely dissipative. The data are described by an isothermal Maxwell slip-boundary condition, and the measured slip-length value was 118 nm .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19..416T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19..416T"><span>Understanding the evolution of channeling and fracturing in porous medium <span class="hlt">due</span> to fluid <span class="hlt">flow</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Daniel, Guillaume; Langliné, Olivier; Grude Flekkøy, Eirik; Jørgen Måløy, Knut</p> <p>2017-04-01</p> <p> sources of the recorded signal (vibrations <span class="hlt">due</span> to <span class="hlt">air</span>, changes in the effective stress <span class="hlt">due</span> to fluid-solid interactions) are separately analyzed using a far field approximation of Lamb waves. In the analysis phase, power spectrum of different timewindows (5 ms) obtained from the recorded signal are computed. We found that, in the synthetic dataset, the peaks in the low frequency range (f < 20 kHz) diminishes while the medium fractures as suggested in experimental work. Furthermore, to localize these events, we propose a new localization method applicable for thin plates which is based on energy amplitude attenuation and inversed source amplitude comparison. This inversion is tested on synthetic data using a direct model of Lamb wave propagation and on experimental dataset. Moreover, the characteristic properties of the different type of earthquakes (namely Type-A and Type-B) are compared with different type of events (defined based on their power spectral signatures) recorded in the Hele-Shaw cell during experiments. Using optical and acoustic datasets and numerical simulations, the mechanics leading Type-A and Type-B earthquakes are explained and the results are shown to be compatible with the real earthquakes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14525017','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14525017"><span>Characterization of <span class="hlt">flow</span> reduction properties in an aneurysm <span class="hlt">due</span> to a stent.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hirabayashi, Miki; Ohta, Makoto; Rüfenacht, Daniel A; Chopard, Bastien</p> <p>2003-08-01</p> <p>We consider a lattice Boltzmann simulation of blood <span class="hlt">flow</span> in a vessel deformed by the presence of an aneurysm. Modern clinical treatments involve introducing a stent (a tubular mesh of wires) into the cerebral artery in order to reduce the <span class="hlt">flow</span> inside the aneurysm and favor its spontaneous reabsorption. A crucial question is to design the stent with suitable porosity so as to produce the most effective <span class="hlt">flow</span> reduction. We propose a stent positioning factor as a characterizing tool for stent pore design in order to describe the <span class="hlt">flow</span> reduction effect and reveal the several <span class="hlt">flow</span> reduction mechanisms using this effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100003381','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100003381"><span>Experimental and Numerical Investigation of <span class="hlt">Flow</span> Properties of Supersonic Helium-<span class="hlt">Air</span> Jets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, Steven A. E.; Veltin, Jeremy</p> <p>2010-01-01</p> <p>Heated high speed subsonic and supersonic jets operating on- or off-design are a source of noise that is not yet fully understood. Helium-<span class="hlt">air</span> mixtures can be used in the correct ratio to simulate the total temperature ratio of heated <span class="hlt">air</span> jets and hence have the potential to provide inexpensive and reliable <span class="hlt">flow</span> and acoustic measurements. This study presents a combination of <span class="hlt">flow</span> measurements of helium-<span class="hlt">air</span> high speed jets and numerical simulations of similar helium-<span class="hlt">air</span> mixture and heated <span class="hlt">air</span> jets. Jets issuing from axisymmetric convergent and convergent-divergent nozzles are investigated, and the results show very strong similarity with heated <span class="hlt">air</span> jet measurements found in the literature. This demonstrates the validity of simulating heated high speed jets with helium-<span class="hlt">air</span> in the laboratory, together with the excellent agreement obtained in the presented data between the numerical predictions and the experiments. The very close match between the numerical and experimental data also validates the frozen chemistry model used in the numerical simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880065908&hterms=Clean+air&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DClean%2Bair','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880065908&hterms=Clean+air&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DClean%2Bair"><span>Unique, clean-<span class="hlt">air</span>, continuous-<span class="hlt">flow</span>, high-stagnation-temperature facility for supersonic combustion research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Krauss, R. H.; Mcdaniel, J. C., Jr.; Scott, J. E., Jr.; Whitehurst, R. B., III; Segal, C.</p> <p>1988-01-01</p> <p>Accurate, spatially-resolved measurements can be conducted of a model supersonic combustor in a clean <span class="hlt">air</span>/continuous <span class="hlt">flow</span> supersonic combustion facility whose long run times will allow not only the point-by-point mapping of <span class="hlt">flow</span> field variables with laser diagnostics but facilitate the simulation of steady-state combustor conditions. The facility will provide a Mach 2 freestream with static pressures in the 1 to 1/6 atm range, and stagnation temperatures of up to 2000 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/316097','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/316097"><span><span class="hlt">Air</span>-side <span class="hlt">flow</span> and heat transfer in compact heat exchangers: A discussion of enhancement mechanisms</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jacobi, A.M.; Shah, R.K.</p> <p>1998-10-01</p> <p>The behavior of <span class="hlt">air</span> <span class="hlt">flows</span> in complex heat exchanger passages is reviewed with a focus on the heat transfer effects of boundary-layer development, turbulence, spanwise and streamwise vortices, and wake management. Each of these <span class="hlt">flow</span> features is discussed for the plain, wavy, and interrupted passages found in contemporary compact heat exchanger designs. Results from the literature are used to help explain the role of these mechanisms in heat transfer enhancement strategies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880065908&hterms=clean+air&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dclean%2Bair','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880065908&hterms=clean+air&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dclean%2Bair"><span>Unique, clean-<span class="hlt">air</span>, continuous-<span class="hlt">flow</span>, high-stagnation-temperature facility for supersonic combustion research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Krauss, R. H.; Mcdaniel, J. C., Jr.; Scott, J. E., Jr.; Whitehurst, R. B., III; Segal, C.</p> <p>1988-01-01</p> <p>Accurate, spatially-resolved measurements can be conducted of a model supersonic combustor in a clean <span class="hlt">air</span>/continuous <span class="hlt">flow</span> supersonic combustion facility whose long run times will allow not only the point-by-point mapping of <span class="hlt">flow</span> field variables with laser diagnostics but facilitate the simulation of steady-state combustor conditions. The facility will provide a Mach 2 freestream with static pressures in the 1 to 1/6 atm range, and stagnation temperatures of up to 2000 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26860399','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26860399"><span>Tracheostomy Tube Type and Inner Cannula Selection Impact Pressure and Resistance to <span class="hlt">Air</span> <span class="hlt">Flow</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pryor, Lee N; Baldwin, Claire E; Ward, Elizabeth C; Cornwell, Petrea L; O'Connor, Stephanie N; Chapman, Marianne J; Bersten, Andrew D</p> <p>2016-05-01</p> <p>Advancements in tracheostomy tube design now provide clinicians with a range of options to facilitate communication for individuals receiving ventilator assistance through a cuffed tube. Little is known about the impact of these modern design features on resistance to <span class="hlt">air</span> <span class="hlt">flow</span>. We undertook a bench model test to measure pressure-<span class="hlt">flow</span> characteristics and resistance of a range of tubes of similar outer diameter, including those enabling subglottic suction and speech. A constant inspiratory ± expiratory <span class="hlt">air</span> <span class="hlt">flow</span> was generated at increasing <span class="hlt">flows</span> up to 150 L/min through each tube (with or without optional, mandatory, or interchangeable inner cannula). Driving pressures were measured, and resistance was calculated (cm H2O/L/s). Pressures changed with increasing <span class="hlt">flow</span> (P < .001) and tube type (P < .001), with differing patterns of pressure change according to the type of tube (P < .001) and direction of <span class="hlt">air</span> <span class="hlt">flow</span>. The single-lumen reference tube encountered the lowest inspiratory and expiratory pressures compared with all double-lumen tubes (P < .001); placement of an optional inner cannula increased bidirectional tube resistance by a factor of 3. For a tube with interchangeable inner cannulas, the type of cannula altered pressure and resistance differently (P < .001); the speech cannula in particular amplified pressure-<span class="hlt">flow</span> changes and increased tube resistance by more than a factor of 4. Tracheostomy tube type and inner cannula selection imposed differing pressures and resistance to <span class="hlt">air</span> <span class="hlt">flow</span> during inspiration and expiration. These differences may be important when selecting airway equipment or when setting parameters for monitoring, particularly for patients receiving supported ventilation or during the weaning process. Copyright © 2016 by Daedalus Enterprises.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/wri99-4224/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/wri99-4224/"><span>Hydrogeology and simulation of ground-water <span class="hlt">flow</span> at Dover <span class="hlt">Air</span> Force Base, Delaware</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hinaman, Kurt C.; Tenbus, Frederick J.</p> <p>2000-01-01</p> <p>, water drains off these highs and the vertical gradients decrease. At the south end of Dover <span class="hlt">Air</span> Force Base, hydrographs of water levels in the Frederica aquifer show that off-Base pumping can cause the water levels to decline below sea level during part of the year.A 4-layer, steady-state numerical model of ground-water <span class="hlt">flow</span> was developed for Dover <span class="hlt">Air</span> Force Base and the surrounding area. The upper two layers represent the upper and lower surficial aquifers, which are in the Columbia Formation. In some areas of the model, a semi-confining unit is used to represent an intermittent clay layer between the upper and lower surficial aquifer. This semi-confining unit causes the local groundwater highs in the surficial aquifer. The third model layer represents the upper part of the Calvert Formation, a confining unit. The fourth model layer represents the Frederica aquifer. The model was calibrated to hydraulic heads and to ground-water discharge in Pipe Elm Branch, both of which were measured in September 1997. For the calibrated model, the root-mean-squared errors for the hydraulic heads and the ground-water discharge in the Pipe Elm Branch were 9 percent of the range of head and 3 percent of discharge, respectively. Heads simulated by use of the model were consistent with a map showing average water levels in the region. The U.S. Geological Survey?s MODPATH program was used to simulate ground-water-<span class="hlt">flow</span> directions for several areas on the Base. This analysis showed the effects of the local groundwater highs. In these areas, ground water can <span class="hlt">flow</span> from the highs and then dramatically change <span class="hlt">flow</span> direction as it enters the lower surficial aquifer. The steady-state model has several limitations. The entire ground-water system is under transient hydraulic conditions, <span class="hlt">due</span> mainly to seasonal and yearly changes in recharge and to withdrawal from irrigation wells. Yet this steady-state model is still considered to be an effective tool for understanding the ground-water-<span class="hlt">flow</span> system u</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26421944','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26421944"><span>Health impacts <span class="hlt">due</span> to particulate <span class="hlt">air</span> pollution in Volos City, Greece.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moustris, Konstantinos P; Proias, George T; Larissi, Ioanna K; Nastos, Panagiotis T; Koukouletsos, Konstantinos V; Paliatsos, Athanasios G</p> <p>2016-01-01</p> <p>There is great consensus among the scientific community that suspended particulate matter is considered as one of the most harmful pollutants, particularly the inhalable particulate matter with aerodynamic diameter less than 10 μm (PM10) causing respiratory health problems and heart disorders. Average daily concentrations exceeding established standard values appear, among other cases, to be the main cause of such episodes, especially during Saharan dust episodes, a natural phenomenon that degrades <span class="hlt">air</span> quality in the urban area of Volos. In this study the <span class="hlt">Air</span>Q2.2.3 model, developed by the World Health Organization (WHO) European Center for Environment and Health, was used to evaluate adverse health effects by PM10 pollution in the city of Volos during a 5-year period (2007-2011). Volos is a coastal medium size city in the Thessaly region. The city is located on the northern side of the Gulf of Pagassitikos, on the east coast of Central Greece. <span class="hlt">Air</span> pollution data were obtained by a fully automated monitoring station, which was established by the Municipal Water Supply and Sewage Department in the Greater Area of Volos, located in the centre of the city. The results of the current study indicate that when the mean annual PM10 concentration exceeds the corresponding European Union (EU) threshold value, the number of hospital admissions for respiratory disease (HARD) is increased by 25% on average. There is also an estimated increase of about 2.5% in HARD compared to the expected annual HARD cases for Volos. Finally, a strong correlation was found between the number of days exceeding the EU daily threshold concentration ([PM10] ≥ 50 μg m(-3)) and the annual HARD cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACP....13.7023L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACP....13.7023L"><span>Model calculated global, regional and megacity premature mortality <span class="hlt">due</span> to <span class="hlt">air</span> pollution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lelieveld, J.; Barlas, C.; Giannadaki, D.; Pozzer, A.</p> <p>2013-07-01</p> <p><span class="hlt">Air</span> pollution by fine particulate matter (PM2.5) and ozone (O3) has increased strongly with industrialization and urbanization. We estimate the premature mortality rates and the years of human life lost (YLL) caused by anthropogenic PM2.5 and O3 in 2005 for epidemiological regions defined by the World Health Organization (WHO). This is based upon high-resolution global model calculations that resolve urban and industrial regions in greater detail compared to previous work. Results indicate that 69% of the global population is exposed to an annual mean anthropogenic PM2.5 concentration of >10 μg m-3 (WHO guideline) and 33% to > 25 μg m-3 (EU directive). We applied an epidemiological health impact function and find that especially in large countries with extensive suburban and rural populations, <span class="hlt">air</span> pollution-induced mortality rates have been underestimated given that previous studies largely focused on the urban environment. We calculate a global respiratory mortality of about 773 thousand/year (YLL ≈ 5.2 million/year), 186 thousand/year by lung cancer (YLL ≈ 1.7 million/year) and 2.0 million/year by cardiovascular disease (YLL ≈ 14.3 million/year). The global mean per capita mortality caused by <span class="hlt">air</span> pollution is about 0.1% yr-1. The highest premature mortality rates are found in the Southeast Asia and Western Pacific regions (about 25% and 46% of the global rate, respectively) where more than a dozen of the most highly polluted megacities are located.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2078490','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2078490"><span>Occupational exposure to particulate <span class="hlt">air</span> pollution and mortality <span class="hlt">due</span> to ischaemic heart disease and cerebrovascular disease</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Torén, Kjell; Bergdahl, Ingvar A; Nilsson, Tohr; Järvholm, Bengt</p> <p>2007-01-01</p> <p>Objectives A growing number of epidemiological studies are showing that ambient exposure to particulate matter <span class="hlt">air</span> pollution is a risk factor for cardiovascular disease; however, whether occupational exposure increases this risk is not clear. The aim of the present study was to examine whether occupational exposure to particulate <span class="hlt">air</span> pollution increases the risk for ischaemic heart disease and cerebrovascular disease. Methods The study population was a cohort of 176 309 occupationally exposed Swedish male construction workers and 71 778 unexposed male construction workers. The definition of exposure to inorganic dust (asbestos, man‐made mineral fibres, dust from cement, concrete and quartz), wood dust, fumes (metal fumes, asphalt fumes and diesel exhaust) and gases and irritants (organic solvents and reactive chemicals) was based on a job‐exposure matrix with focus on exposure in the mid‐1970s. The cohort was followed from 1971 to 2002 with regard to mortality to ischaemic heart disease and cerebrovascular disease. Relative risks (RR) were obtained by the person‐years method and from Poisson regression models adjusting for baseline values of blood pressure, body mass index, age and smoking habits. Results Any occupational particulate <span class="hlt">air</span> pollution was associated with an increased risk for ischemic heart disease (RR 1.13, 95% CI 1.07 to 1.19), but there was no increased risk for cerebrovascular disease (RR 0.97, 95% CI 0.88 to 1.07). There was an increased risk for ischaemic heart disease and exposure to inorganic dust (RR 1.07, 95% CI 1.03 to 1.12) and exposure to fumes (RR 1.05, 95% CI 1.00 to 1.10), especially diesel exhaust (RR 1.18, 95% CI 1.13 to 1.24). There was no significantly increased risk for cerebrovascular disease and exposure to inorganic dust, fumes or wood dust. Conclusions Occupational exposure to particulate <span class="hlt">air</span> pollution, especially diesel exhaust, among construction workers increases the risk for ischaemic heart disease. PMID</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ExFl...54.1493B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ExFl...54.1493B"><span>Secondary <span class="hlt">flow</span> morphologies <span class="hlt">due</span> to model stent-induced perturbations in a 180° curved tube during systolic deceleration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bulusu, Kartik V.; Plesniak, Michael W.</p> <p>2013-03-01</p> <p>Morphological changes in secondary <span class="hlt">flow</span> structures <span class="hlt">due</span> to a stent model were investigated under physiological inflow conditions. The stent model was inserted upstream of a 180° curved tube artery model. A carotid artery <span class="hlt">flow</span> rate with its characteristic systolic and diastolic phases was supplied by a pump to drive a blood-analog working fluid. Phase-averaged, two-component, two-dimensional (2C-2D) particle image velocimeter measurements revealed the changing morphologies of these secondary <span class="hlt">flow</span> structures. Continuous wavelet transforms provided an enhanced means to detect coherent secondary <span class="hlt">flow</span> structures in this bio-inspired experimental study. A two-dimensional Ricker wavelet was used, and the optimal wavelet scale was determined using Shannon entropy as a measure of randomness in the wavelet-transformed vorticity fields. Planar secondary <span class="hlt">flow</span> vortical structures at the 90° location in the curved tube were observed to exhibit distinct spatio-temporal characteristics different than the baseline <span class="hlt">flow</span> without the stent. <span class="hlt">Flow</span> patterns observed at the systolic peak comprised of early Lyne-type, along with a deformed Dean-type pair of ordered, coherent, high-circulation and counter-rotating vortical structures. Systolic deceleration was marked by the breakdown of large-scale coherent vortices into multiple, disordered, low-circulation, coherent vortical structures, indicating new transitional secondary <span class="hlt">flow</span> morphologies. These multi-scale secondary <span class="hlt">flow</span> morphologies arise <span class="hlt">due</span> to the combination of imbalances in centrifugal and pressure forces, and stent-induced <span class="hlt">flow</span> perturbations. The detailed <span class="hlt">flow</span> physics associated with the formation of Dean and Lyne vortices are described in previous publications that have been cited in the manuscript. The secondary <span class="hlt">flow</span> structures reported here are driven by similar fundamental mechanisms, but additionally contain more complicated effects, such as asymmetry and multiple strengths, that cannot be predicted from simple theories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/271903','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/271903"><span>Compressed <span class="hlt">air</span> energy storage system two-phase <span class="hlt">flow</span> experiment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kumamaru, Hiroshige; Ohtsu, Iwao; Murata, Hideo</p> <p>1996-08-01</p> <p>A water/CO{sub 2}-combination test facility, having a vertical shaft height of {approximately} 25 m and a shaft inner diameter of 0.2 m, has been constructed in simulating a water/<span class="hlt">air</span> full-size CAES system, having a shaft height of {approximately} 1,000 m and an inner diameter of {approximately} 3 m. Totally fifteen experiments have been performed in this test facility. In an experiment of CO{sub 2} high-concentration ({approximately} 0.4 MPa) and medium water injection velocity ({approximately} 0.5 m/s), the shaft void fraction during gas charging to a lower reservoir (i.e. during water injection to the shaft) became highest in all the experiment. This experiment may correspond to the severest situation in a full-size CAES system; however, the blowout did not occur in this experiment. In an experiment of CO{sub 2} high-concentration({approximately} 0.4 MPa) and very-high injection velocity ({approximately} 2.5 m/s), after gas charging stopped, CO{sub 2}-supersaturated water, remained in the shaft, formed bubbles vigorously, and thereafter the blowout occurred. However, the injection velocity of {approximately} 2.5 m/s corresponds to a velocity of {approximately} 100 m/s in a full-size CAES system and may be unreal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1738.0002R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1738.0002R"><span>Instability <span class="hlt">due</span> to interfacial tension in parallel liquid-liquid <span class="hlt">flow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodriguez, Oscar M. H.</p> <p>2016-06-01</p> <p>The frequent occurrence of multiphase <span class="hlt">flows</span> in pipes has motivated a great research interest over the last decades. The particular case of liquid-liquid <span class="hlt">flow</span> is commonly encountered in the petroleum industry, where a number of applications involve oil-water <span class="hlt">flow</span> such as crude oil production in directional wells. However, it has not received the same attention when compared to gas-liquid <span class="hlt">flow</span>. In addition, most of the available information has to do with <span class="hlt">flow</span> in pipes. When it comes to <span class="hlt">flows</span> in annular ducts the data are scanty. A general transition criterion has been recently proposed in order to obtain the stratified and core-annular <span class="hlt">flow</span>-pattern transition boundaries in viscous oil-water <span class="hlt">flow</span>. The proposed criterion was based on an one-dimensional two-fluid model of liquid-liquid two-phase <span class="hlt">flow</span>. A stability analysis was carried out and interfacial tension is considered. A new destabilizing term arises, which is a function of the cross-section curvature of the interface. It is well accepted that interfacial tension favors the stable condition. However, the analysis of the new interfacial-tension term shows that it can actually destabilize the basic <span class="hlt">flow</span> pattern, playing an important role in regions of extreme volumetric fractions. Such an interesting effect seems to be more pronounced in <span class="hlt">flows</span> of viscous fluids and in annular-duct <span class="hlt">flow</span>. The effect of interfacial tension is explored and the advantages of using a more complete model are discussed and illustrated through comparisons with experimental data from the literature. The evaluation of the effects of fluid viscosity and interfacial tension allows the correction and enhancement of transition models based essentially on data of pipe <span class="hlt">flow</span> of low viscosity fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920001764','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920001764"><span>Viscous computations of cold <span class="hlt">air/air</span> <span class="hlt">flow</span> around scramjet nozzle afterbody</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baysal, Oktay; Engelund, Walter C.</p> <p>1991-01-01</p> <p>The <span class="hlt">flow</span> field in and around the nozzle afterbody section of a hypersonic vehicle was computationally simulated. The compressible, Reynolds averaged, Navier Stokes equations were solved by an implicit, finite volume, characteristic based method. The computational grids were adapted to the <span class="hlt">flow</span> as the solutions were developing in order to improve the accuracy. The exhaust gases were assumed to be cold. The computational results were obtained for the two dimensional longitudinal plane located at the half span of the internal portion of the nozzle for over expanded and under expanded conditions. Another set of results were obtained, where the three dimensional simulations were performed for a half span nozzle. The surface pressures were successfully compared with the data obtained from the wind tunnel tests. The results help in understanding this complex <span class="hlt">flow</span> field and, in turn, should help the design of the nozzle afterbody section.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22017463','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22017463"><span>The effect of moist <span class="hlt">air</span> on skin blood <span class="hlt">flow</span> and temperature in subjects with and without diabetes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Petrofsky, Jerrold; Berk, Lee; Alshammari, Faris; Lee, Haneul; Hamdan, Adel; Yim, Jong Eun; Patel, Denis; Kodawala, Yusufi; Shetye, Gauri; Chen, Wei-Ti; Moniz, Harold; Pathak, Kunal; Somanaboina, Karunakar; Desai, Rajavi; Dave, Bhargav; Malthane, Swapnil; Alshaharani, Mastour; Neupane, Sushma; Shenoy, Samruddha; Nevgi, Bhakti; Cho, Sungkwan; Al-Nakhli, Hani</p> <p>2012-02-01</p> <p>Endothelial function is known to be impaired in response to heat in people with diabetes, but little has been done to see how <span class="hlt">air</span> humidity alters the skin blood <span class="hlt">flow</span> response to heat. Seventeen male and female subjects were divided in two groups, one with type 2 diabetes and the other the control subjects without diabetes, age-matched to the diabetes group. All subjects participated in a series of experiments to determine the effect of the warming of the skin by <span class="hlt">air</span> on skin temperature and skin blood <span class="hlt">flow</span>. On different days, skin temperature was warmed with <span class="hlt">air</span> that was 38°C, 40°C, or 42°C for 20 min. Also, on different days, at each temperature, the <span class="hlt">air</span> humidity was adjusted to 0%, 25%, 50%, 75%, or 100% humidity. Skin blood <span class="hlt">flow</span> and temperature were measured throughout the exposure period. This allowed the interactions between <span class="hlt">air</span> humidity and temperature to be assessed. For the control subjects, the moisture in the <span class="hlt">air</span> had no different effect on skin blood <span class="hlt">flow</span> at <span class="hlt">air</span> temperatures of 38°C and 40°C (analysis of variance, P>0.05), although skin blood <span class="hlt">flow</span> progressively increased at each <span class="hlt">air</span> temperature that was applied. But for the warmest <span class="hlt">air</span> temperature, 42°C, although the four lower humidities had the same effect on skin blood <span class="hlt">flow</span>, <span class="hlt">air</span> at 100% humidity caused the largest increase in skin blood <span class="hlt">flow</span>. In contrast, in the subjects with diabetes, blood <span class="hlt">flow</span> was always significantly less at any <span class="hlt">air</span> temperature applied to the skin than was observed in the control subjects (P<0.05), and skin blood <span class="hlt">flow</span> was significantly higher for the two higher humidities for the two higher <span class="hlt">air</span> temperatures. Skin temperature paralleled these findings. These data show that individuals with diabetes do not tolerate moist, warm <span class="hlt">air</span> above 50% humidity as well as controls without diabetes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDM14001S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDM14001S"><span>Experimental studies of the streaming <span class="hlt">flow</span> <span class="hlt">due</span> to the adsorption of particles at a liquid surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Pushpendra; Musunuri, Naga; Fischer, Ian</p> <p>2016-11-01</p> <p>The particle image velocimetry (PIV) technique is used to study the streaming <span class="hlt">flow</span> that is induced when particles are adsorbed at a liquid surface. The <span class="hlt">flow</span> develops within a fraction of second after the adsorption of the particle and persists for several seconds. The fluid directly below the particle rises upward, and near the surface, it moves away from the particle. The <span class="hlt">flow</span> causes powders sprinkled on a liquid surface to disperse on the surface. The <span class="hlt">flow</span> strength, and the volume over which it extends, decreases with decreasing particle size. The streaming <span class="hlt">flow</span> induced by the adsorption of two or more particles is a combination of the <span class="hlt">flows</span> which they induce individually. The work was supported by National Science Foundation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJMPC..2750147S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJMPC..2750147S"><span>Occurrence of synchronized <span class="hlt">flow</span> <span class="hlt">due</span> to overtaking strategy in the Nagel-Schreckenberg model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Zhu; Deng, Weibing; Han, Jihui; Li, Wei; Cai, Xu</p> <p>2016-06-01</p> <p>The Nagel-Schreckenberg model with overtaking strategy (NSOS) is proposed, and numerical simulations are performed for both closed and open boundary conditions. The fundamental diagram, space-time diagram and spatial-temporal distribution of speed are investigated. In order to identify the synchronized <span class="hlt">flow</span> state, both the correlation functions (autocorrelation and cross-correlation) and the one-minute average <span class="hlt">flow</span> rate versus density diagram are studied. All the results verify that synchronized <span class="hlt">flow</span> does occur in our model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740050393&hterms=sound+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsound%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740050393&hterms=sound+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsound%2Benergy"><span>Sound propagation through a real jet <span class="hlt">flow</span> field with scattering <span class="hlt">due</span> to interaction with turbulence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Maestrello, L.; Liu, C. H.; Ting, L.; Gunzburger, M.</p> <p>1974-01-01</p> <p>The sound propagation through a nonuniform turbulent jet <span class="hlt">flow</span> field is studied by means of a system of linearized equations governing the acoustic variables. These equations depend on the fluctuating <span class="hlt">flow</span>-field variables which are prescribed by experimental results. It is shown that the redistribution of the acoustic energy in the far field depends on space-time correlation of the turbulent velocities and on the mean <span class="hlt">flow</span> variables and their gradients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhFl...29i5104A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhFl...29i5104A"><span>In-cylinder <span class="hlt">air-flow</span> characteristics of different intake port geometries using tomographic PIV</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agarwal, Avinash Kumar; Gadekar, Suresh; Singh, Akhilendra Pratap</p> <p>2017-09-01</p> <p>For improving the in-cylinder <span class="hlt">flow</span> characteristics of intake <span class="hlt">air</span>/charge and for strengthening the turbulence intensity, specific intake port geometries have shown significant potential in compression ignition engines. In this experimental study, effects of intake port geometries on <span class="hlt">air-flow</span> characteristics were investigated using tomographic particle imaging velocimetry (TPIV). Experiments were performed using three experimental conditions, namely, swirl port open (SPO), tangential port open (TPO), and both port open (BPO) configurations in a single cylinder optical research engine. <span class="hlt">Flow</span> investigations were carried out in a volumetric section located in the middle of the intake and exhaust valves. Particle imaging velocimetry (PIV) images were captured using two high speed cameras at a crank angle resolution of 2° in the intake and compression strokes. The captured PIV images were then pre-processed and post-processed to obtain the final <span class="hlt">air-flow</span>-field. Effects of these two intake ports on <span class="hlt">flow</span>-field are presented for <span class="hlt">air</span> velocity, vorticity, average absolute velocity, and turbulent kinetic energy. Analysis of these <span class="hlt">flow</span>-fields suggests the dominating nature of the swirl port over the tangential port for the BPO configuration and higher rate of <span class="hlt">flow</span> energy dissipation for the TPO configuration compared to the SPO and BPO configurations. These findings of TPIV investigations were experimentally verified by combustion and particulate characteristics of the test engine in thermal cylinder head configuration. Combustion results showed that the SPO configuration resulted in superior combustion amongst all three port configurations. Particulate characteristics showed that the TPO configuration resulted in higher particulate compared to other port configurations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050028474','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050028474"><span>An Experimental Investigation of the <span class="hlt">Flow</span> of <span class="hlt">Air</span> in a Flat Broadening Channel</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vedernikoff, A. N.</p> <p>1944-01-01</p> <p>The wide use of diffusers, in various fields of technology, has resulted in several experimental projects to study the action and design of diffusers. Most of the projects dealt with steam (steam turbine nozzles). But diffusers have other applications - that is, ventilators, smoke ducts, <span class="hlt">air</span> coolers, refrigeration, drying, and so forth. At present there is another application for diffusers in wind-tunnel design. Because of higher requirements and increased power of such installations more attention must be paid to the correctness of work and the decrease in losses <span class="hlt">due</span> to every section of the tunnel. A diffuser, being one of the component parts of a tunnel , can in the event of faulty construction introduce considerable losses. Therefore, in the design of the new CAHI wind tunnel, it was suggested that an experimental study of diffusers be made, with a view to applying the results to wind tunnels. The experiments conducted by K. K. Baulin in the laboratories of CAHI upon models of diffusers of different cross sections, lengths, and angles of divergence, were a valuable source of experimental data. They were of no help, however, in reaching any conclusion regarding the optimum shape because of the complexity and diversity of the factors which all appeared simultaneously, thereby precluding the.study of the effects of any one factor separately. On the suggestion of the director of the CAHI,Prof. B. N. Ureff, it was decided to experiment on a two-dimensional diffuser model and determine the effect, of the angle of divergence. The author is acquainted with two experimental projects of like nature: the first was conducted with water, the other with <span class="hlt">air</span>. The first of these works, although containing a wealth of experimental data, does not indicate the nature of <span class="hlt">flow</span> or its relation to the angle of divergence. The second work is limited to four angles - that is, 12 deg, 24 deg, 45 deg, 90 deg. The study of this diffuser did not supply any information about the effect of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910064614&hterms=Argon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DArgon','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910064614&hterms=Argon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DArgon"><span>High enthalpy, hypervelocity <span class="hlt">flows</span> of <span class="hlt">air</span> and argon in an expansion tube</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neely, A. J; Stalker, R. J.; Paull, A.</p> <p>1991-01-01</p> <p>An expansion tube with a free piston driver has been used to generate quasi-steady hypersonic <span class="hlt">flows</span> in argon and <span class="hlt">air</span> at <span class="hlt">flow</span> velocities in excess of 9 km/s. Irregular test <span class="hlt">flow</span> unsteadiness has limited the performance of previous expansion tubes, and it has been found that this can be avoided by attention to the interaction between the test gas accelerating expansion and the contact surface in the primary shock tube. Test section measurements of pitot pressure, static pressure and flat plate heat transfer are reported. An approximate analytical theory has been developed for predicting the velocities achieved in the unsteady expansion of the ionizing or dissociating test gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910064614&hterms=enthalpy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Denthalpy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910064614&hterms=enthalpy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Denthalpy"><span>High enthalpy, hypervelocity <span class="hlt">flows</span> of <span class="hlt">air</span> and argon in an expansion tube</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Neely, A. J; Stalker, R. J.; Paull, A.</p> <p>1991-01-01</p> <p>An expansion tube with a free piston driver has been used to generate quasi-steady hypersonic <span class="hlt">flows</span> in argon and <span class="hlt">air</span> at <span class="hlt">flow</span> velocities in excess of 9 km/s. Irregular test <span class="hlt">flow</span> unsteadiness has limited the performance of previous expansion tubes, and it has been found that this can be avoided by attention to the interaction between the test gas accelerating expansion and the contact surface in the primary shock tube. Test section measurements of pitot pressure, static pressure and flat plate heat transfer are reported. An approximate analytical theory has been developed for predicting the velocities achieved in the unsteady expansion of the ionizing or dissociating test gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..GECCT2004K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..GECCT2004K"><span>Optical Diagnostics of <span class="hlt">Air</span> <span class="hlt">Flows</span> Induced in Surface Dielectric Barrier Discharge Plasma Actuator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kobatake, Takuya; Deguchi, Masanori; Suzuki, Junya; Eriguchi, Koji; Ono, Kouichi</p> <p>2014-10-01</p> <p>A surface dielectric barrier discharge (SDBD) plasma actuator has recently been intensively studied for the <span class="hlt">flow</span> control over airfoils and turbine blades in the fields of aerospace and aeromechanics. It consists of two electrodes placed on both sides of the dielectric, where one is a top powered electrode exposed to the <span class="hlt">air</span>, and the other is a bottom grounded electrode encapsulated with an insulator. The unidirectional gas <span class="hlt">flow</span> along the dielectric surfaces is induced by the electrohydrodynamic (EHD) body force. It is known that the thinner the exposed electrode, the greater the momentum transfer to the <span class="hlt">air</span> is, indicating that the thickness of the plasma is important. To analyze plasma profiles and <span class="hlt">air</span> <span class="hlt">flows</span> induced in the SDBD plasma actuator, we performed time-resolved and -integrated optical emission and schlieren imaging of the side view of the SDBD plasma actuator in atmospheric <span class="hlt">air</span>. We applied a high voltage bipolar pulse (4-8 kV, 1-10 kHz) between electrodes. Experimental results indicated that the spatial extent of the plasma is much smaller than that of the induced <span class="hlt">flows</span>. Experimental results further indicated that in the positive-going phase, a thin and long plasma is generated, where the optical emission is weak and uniform; on the other hand, in the negative-going phase, a thick and short plasma is generated, where a strong optical emission is observed near the top electrode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009APS..DFD.PW010P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009APS..DFD.PW010P"><span>Effects of <span class="hlt">flow</span> on insulin fibril formation at an <span class="hlt">air</span>/water interface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Posada, David; Heldt, Caryn; Sorci, Mirco; Belfort, Georges; Hirsa, Amir</p> <p>2009-11-01</p> <p>The amyloid fibril formation process, which is implicated in several diseases such as Alzheimer's and Huntington's, is characterized by the conversion of monomers to oligomers and then to fibrils. Besides well-studied factors such as pH, temperature and concentration, the kinetics of this process are significantly influenced by the presence of solid or fluid interfaces and by <span class="hlt">flow</span>. By studying the nucleation and growth of a model system (insulin fibrils) in a well-defined <span class="hlt">flow</span> field with an <span class="hlt">air</span>/water interface, we can identify the <span class="hlt">flow</span> conditions that impact protein aggregation kinetics both in the bulk solution and at the <span class="hlt">air</span>/water interface. The present <span class="hlt">flow</span> system (deep-channel surface viscometer) consists of an annular region bounded by stationary inner and outer cylinders, an <span class="hlt">air</span>/water interface, and a floor driven at constant rotation. We show the effects of Reynolds number on the kinetics of the fibrillation process both in the bulk solution and at the <span class="hlt">air</span>/water interface, as well as on the structure of the resultant amyloid aggregates.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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