Sample records for vapor pressure gradient

  1. On Localized Vapor Pressure Gradients Governing Condensation and Frost Phenomena.

    PubMed

    Nath, Saurabh; Boreyko, Jonathan B

    2016-08-23

    Interdroplet vapor pressure gradients are the driving mechanism for several phase-change phenomena such as condensation dry zones, interdroplet ice bridging, dry zones around ice, and frost halos. Despite the fundamental nature of the underlying pressure gradients, the majority of studies on these emerging phenomena have been primarily empirical. Using classical nucleation theory and Becker-Döring embryo formation kinetics, here we calculate the pressure field for all possible modes of condensation and desublimation in order to gain fundamental insight into how pressure gradients govern the behavior of dry zones, condensation frosting, and frost halos. Our findings reveal that in a variety of phase-change systems the thermodynamically favorable mode of nucleation can switch between condensation and desublimation depending upon the temperature and wettability of the surface. The calculated pressure field is used to model the length of a dry zone around liquid or ice droplets over a broad parameter space. The long-standing question of whether the vapor pressure at the interface of growing frost is saturated or supersaturated is resolved by considering the kinetics of interdroplet ice bridging. Finally, on the basis of theoretical calculations, we propose that there exists a new mode of frost halo that is yet to be experimentally observed; a bimodal phase map is developed, demonstrating its dependence on the temperature and wettability of the underlying substrate. We hope that the model and predictions contained herein will assist future efforts to exploit localized vapor pressure gradients for the design of spatially controlled or antifrosting phase-change systems.

  2. Temperature gradient effects on vapor diffusion in partially-saturated porous media

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Webb, S.W.

    1999-07-01

    Vapor diffusion in porous media in the presence of its own liquid may be enhanced due to pore-scale processes, such as condensation and evaporation across isolated liquid islands. Webb and Ho (1997) developed one-and two-dimensional mechanistic pore-scale models of these processes in an ideal porous medium. For isothermal and isobaric boundary conditions with a concentration gradient, the vapor diffusion rate was significantly enhanced by these liquid island processes compared to a dry porous media. The influence of a temperature gradient on the enhanced vapor diffusion rate is considered in this paper. The two-dimensional pore network model which is used inmore » the present study is shown. For partially-saturated conditions, a liquid island is introduced into the top center pore. Boundary conditions on the left and right sides of the model are specified to give the desired concentration and temperature gradients. Vapor condenses on one side of the liquid island and evaporates off the other side due to local vapor pressure lowering caused by the interface curvature, even without a temperature gradient. Rather than acting as an impediment to vapor diffusion, the liquid island actually enhances the vapor diffusion rate. The enhancement of the vapor diffusion rate can be significant depending on the liquid saturation. Vapor diffusion is enhanced by up to 40% for this single liquid island compared to a dry porous medium; enhancement factors of up to an order of magnitude have been calculated for other conditions by Webb and Ho (1997). The dominant effect on the enhancement factor is the concentration gradient; the influence of the temperature gradient is smaller. The significance of these results, which need to be confirmed by experiments, is that the dominant model of enhanced vapor diffusion (EVD) by Philip and deVries (1957) predicts that temperature gradients must exist for EVD to occur. If there is no temperature gradient, there is no enhancement. The present

  3. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization whichmore » have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.« less

  4. Estimated vapor pressure for WTP process streams

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pike, J.; Poirier, M.

    Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused bymore » organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.« less

  5. Bacterial chemotaxis along vapor-phase gradients of naphthalene.

    PubMed

    Hanzel, Joanna; Harms, Hauke; Wick, Lukas Y

    2010-12-15

    The role of bacterial growth and translocation for the bioremediation of organic contaminants in the vadose zone is poorly understood. Whereas air-filled pores restrict the mobility of bacteria, diffusion of volatile organic compounds in air is more efficient than in water. Past research, however, has focused on chemotactic swimming of bacteria along gradients of water-dissolved chemicals. In this study we tested if and to what extent Pseudomonas putida PpG7 (NAH7) chemotactically reacts to vapor-phase gradients forming above their swimming medium by the volatilization from a spot source of solid naphthalene. The development of an aqueous naphthalene gradient by air-water partitioning was largely suppressed by means of activated carbon in the agar. Surprisingly, strain PpG7 was repelled by vapor-phase naphthalene although the steady state gaseous concentrations were 50-100 times lower than the aqueous concentrations that result in positive chemotaxis of the same strain. It is thus assumed that the efficient gas-phase diffusion resulting in a steady, and possibly toxic, naphthalene flux to the cells controlled the chemotactic reaction rather than the concentration to which the cells were exposed. To our knowledge this is the first demonstration of apparent chemotactic behavior of bacteria in response to vapor-phase effector gradients.

  6. Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

    ERIC Educational Resources Information Center

    Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

    2007-01-01

    A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

  7. Vapor pressures of new fluorocarbons

    NASA Astrophysics Data System (ADS)

    Kubota, H.; Yamashita, T.; Tanaka, Y.; Makita, T.

    1989-05-01

    The vapor pressures of four fluorocarbons have been measured at the following temperature ranges: R123 (2,2-dichloro-l,l,l-trifluoroethane), 273 457 K; R123a (1,2-dichloro-1,1,2-trifluoroethane), 303 458 K; R134a (1,1,1,2-tetrafluoroethane), 253 373 K; and R132b (l,2-dichloro-l,l-difluoroethane), 273 398 K. Determinations of the vapor pressure were carried out by a constant-volume apparatus with an uncertainty of less than 1.0%. The vapor pressures of R123 and R123a are very similar to those of R11 over the whole experimental temperature range, but the vapor pressures of R134a and R132b differ somewhat from those of R12 and R113, respectively, as the temperature increases. The numerical vapor pressure data can be fitted by an empirical equation using the Chebyshev polynomial with a mean deviation of less than 0.3 %.

  8. Vapor pressures of new fluorocarbons

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kubota, H.; Yamashita, T.; Tanaka, Y.

    1989-05-01

    The vapor pressures of four fluorocarbons have been measured at the following temperature ranges: R123 (2,2-dichloro-1,1,1-trifluoroethane), 273-457 K; R123a (1,2-dichloro-1,1,2-trifluoroethane), 303-458 K; R134a (1,1,1,2-tetrafluoroethane), 253-373 K; and R132b (1,2-dichloro-1,1-difluoroethane), 273-398 K. Determinations of the vapor pressure were carried out by a constant-volume apparatus with an uncertainty of less than 1.0%. The vapor pressures of R123 and R123a are very similar to those of R11 over the whole experimental temperature range, but the vapor pressures of R134a and R132b differ somewhat from those of R12 and R113, respectively, as the temperature increases. The numerical vapor pressure data can be fitted bymore » an empirical equation using the Chebyshev polynomial with a mean deviation of less than 0.3%.« less

  9. Buoyancy-Driven Heat Transfer During Application of a Thermal Gradient for the Study of Vapor Deposition at Low Pressure Using and Ideal Gas

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Hung, R. J.; Paley, M. S.; Penn, B. G.; Long, Y. T.

    1996-01-01

    A mathematical model has been developed to determine heat transfer during vapor deposition of source materials under a variety of orientations relative to gravitational accelerations. The model demonstrates that convection can occur at total pressures as low as 10-2 mm Hg. Through numerical computation, using physical material parameters of air, a series of time steps demonstrates the development of flow and temperature profiles during the course of vapor deposition. These computations show that in unit gravity vapor deposition occurs by transport through a fairly complicated circulating flow pattern when applying heat to the bottom of the vessel with parallel orientation with respect to the gravity vector. The model material parameters for air predict the effect of kinematic viscosity to be of the same order as thermal diffusivity, which is the case for Prandtl number approx. 1 fluids. Qualitative agreement between experiment and the model indicates that 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-l-ol (DAMNA) at these pressures indeed approximates an ideal gas at the experiment temperatures, and may validate the use of air physical constants. It is apparent that complicated nonuniform temperature distribution in the vapor could dramatically affect the homogeneity, orientation, and quality of deposited films. The experimental test i's a qualitative comparison of film thickness using ultraviolet-visible spectroscopy on films generated in appropriately oriented vapor deposition cells. In the case where heating of the reaction vessel occurs from the top, deposition of vapor does not normally occur by convection due to a stable stratified medium. When vapor deposition occurs in vessels heated at the bottom, but oriented relative to the gravity vector between these two extremes, horizontal thermal gradients induce a complex flow pattern. In the plane parallel to the tilt axis, the flow pattern is symmetrical and opposite in direction from that where the vessel is

  10. Vapor Pressure Data Analysis and Statistics

    DTIC Science & Technology

    2016-12-01

    sublimation for solids), volatility, and entropy of volatilization. Vapor pressure can be reported several different ways, including tables of experimental ...account the variation in heat of vaporization with temperature, and accurately describes data over broad experimental ranges, thereby enabling...pressure is incorrect at temperatures far below the experimental temperature limit; the calculated vapor pressure becomes undefined when the

  11. 40 CFR 796.1950 - Vapor pressure.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... gases until the measured vapor pressure is constant, a process called “degassing.” Impurities more... simulations. Vapor pressure is computed on the assumption that the total pressure of a mixture of gases is...

  12. Vapor Pressure Measurements in a Closed System

    ERIC Educational Resources Information Center

    Iannone, Mark

    2006-01-01

    An alternative method that uses a simple apparatus to measure vapor pressure versus temperature in a closed system, in which the total pressure is the vapor pressure of the liquid sample, is described. The use of this apparatus gives students a more direct picture of vapor pressure than the isoteniscope method and results have generally been quite…

  13. Estimating vapor pressures of pure liquids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Haraburda, S.S.

    1996-03-01

    Calculating the vapor pressures for pure liquid chemicals is a key step in designing equipment for separation of liquid mixtures. Here is a useful way to develop an equation for predicting vapor pressures over a range of temperatures. The technique uses known vapor pressure points for different temperatures. Although a vapor-pressure equation is being showcased in this article, the basic method has much broader applicability -- in fact, users can apply it to develop equations for any temperature-dependent model. The method can be easily adapted for use in software programs for mathematics evaluation, minimizing the need for any programming. Themore » model used is the Antoine equation, which typically provides a good correlation with experimental or measured data.« less

  14. Vapor pressure measured with inflatable plastic bag

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.

  15. Vapor Pressure of GB

    DTIC Science & Technology

    2009-04-01

    equation. The Podoll and Parish low temperature measured vapor pressure data (-35 and -25 °C) were included in our analysis . Penski summarized the...existing literature data for GB in his 1994 data review and analysis .6 He did not include the 0 °C Podoll and Parish measured vapor pressure data point...35.9 Pa) in his analysis because the error associated with this point was Ŗ to 10 times greater than the other values". He did not include the -10 °C

  16. Vapor pressures of a homologous series of polyethylene glycols as a reference data set for validating vapor pressure measurement techniques.

    NASA Astrophysics Data System (ADS)

    Krieger, Ulrich; Marcolli, Claudia; Siegrist, Franziska

    2015-04-01

    The production of secondary organic aerosol (SOA) by gas-to-particle partitioning is generally represented by an equilibrium partitioning model. A key physical parameter which governs gas-particle partitioning is the pure component vapor pressure, which is difficult to measure for low- and semivolatile compounds. For typical atmospheric compounds like e.g. citric acid or tartaric acid, vapor pressures have been reported in the literature which differ by up to six orders of magnitude [Huisman et al., 2013]. Here, we report vapor pressures of a homologous series of polyethylene glycols (triethylene glycol to octaethylene glycol) determined by measuring the evaporation rate of single, levitated aerosol particles in an electrodynamic balance. We propose to use those as a reference data set for validating different vapor pressure measurement techniques. With each addition of a (O-CH2-CH2)-group the vapor pressure is lowered by about one order of magnitude which makes it easy to detect the lower limit of vapor pressures accessible with a particular technique down to a pressure of 10-8 Pa at room temperature. Reference: Huisman, A. J., Krieger, U. K., Zuend, A., Marcolli, C., and Peter, T., Atmos. Chem. Phys., 13, 6647-6662, 2013.

  17. Vapor pressure of germanium precursors

    NASA Astrophysics Data System (ADS)

    Pangrác, J.; Fulem, M.; Hulicius, E.; Melichar, K.; Šimeček, T.; Růžička, K.; Morávek, P.; Růžička, V.; Rushworth, S. A.

    2008-11-01

    The vapor pressure of two germanium precursors tetrakis(methoxy)germanium (Ge(OCH 3) 4, CASRN 992-91-6) and tetrakis(ethoxy)germanium (Ge(OC 2H 5) 4, CASRN 14165-55-0) was determined using a static method in the temperature range 259-303 K. The experimental vapor pressure data were fit with the Antoine equation. The mass spectra before and after degassing by vacuum distillation at low temperature are also reported and discussed.

  18. 46 CFR 30.10-59 - Reid vapor pressure-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-59 Reid vapor pressure—TB/ALL. The term Reid vapor pressure means the vapor pressure of a liquid at a... 46 Shipping 1 2013-10-01 2013-10-01 false Reid vapor pressure-TB/ALL. 30.10-59 Section 30.10-59....01-3), Method of Test for Vapor Pressure of Petroleum Products. This Standard is available at...

  19. 46 CFR 30.10-59 - Reid vapor pressure-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-59 Reid vapor pressure—TB/ALL. The term Reid vapor pressure means the vapor pressure of a liquid at a... 46 Shipping 1 2012-10-01 2012-10-01 false Reid vapor pressure-TB/ALL. 30.10-59 Section 30.10-59....01-3), Method of Test for Vapor Pressure of Petroleum Products. This Standard is available at...

  20. 46 CFR 30.10-59 - Reid vapor pressure-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-59 Reid vapor pressure—TB/ALL. The term Reid vapor pressure means the vapor pressure of a liquid at a... 46 Shipping 1 2014-10-01 2014-10-01 false Reid vapor pressure-TB/ALL. 30.10-59 Section 30.10-59....01-3), Method of Test for Vapor Pressure of Petroleum Products. This Standard is available at...

  1. Vapor Pressure of Methyl Salicylate and n-Hexadecane

    DTIC Science & Technology

    2014-01-01

    VAPOR PRESSURE OF METHYL SALICYLATE AND N-HEXADECANE ECBC-TR-1184 David E. Tevault Leonard C. Buettner...REPORT TYPE Final 3. DATES COVERED (From - To) Mar 2000-Dec 2001 4. TITLE AND SUBTITLE Vapor Pressure of Methyl Salicylate and n-Hexadecane 5a...ABSTRACT Vapor pressure data are reported for O-hydroxybenzoic acid, methyl ester, more commonly known as methyl salicylate (MeS), and n-hexadecane in

  2. Fuel Vapor Pressures and the Relation of Vapor Pressure to the Preparation of Fuel for Combustion in Fuel Injection Engines

    NASA Technical Reports Server (NTRS)

    Joachim, William F; Rothrock, A M

    1930-01-01

    This investigation on the vapor pressure of fuels was conducted in connection with the general research on combustion in fuel injection engines. The purpose of the investigation was to study the effects of high temperatures such as exist during the first stages of injection on the vapor pressures of several fuels and certain fuel mixtures, and the relation of these vapor pressures to the preparation of the fuel for combustion in high-speed fuel injection engines.

  3. Vapor pressures of acetylene at low temperatures

    NASA Technical Reports Server (NTRS)

    Masterson, C. M.; Allen, John E., Jr.; Kraus, G. F.; Khanna, R. K.

    1990-01-01

    The atmospheres of many of the outer planets and their satellites contain a large number of hydrocarbon species. In particular, acetylene (C2H2) has been identified at Jupiter, Saturn and its satellite Titan, Uranus and Neptune. In the lower atmospheres of these planets, where colder temperatures prevail, the condensation and/or freezing of acetylene is probable. In order to obtain accurate models of the acetylene in these atmospheres, it is necessary to have a complete understanding of its vapor pressures at low temperatures. Vapor pressures at low temperatures for acetylene are being determined. The vapor pressures are measured with two different techniques in order to cover a wide range of temperatures and pressures. In the first, the acetylene is placed in a sample tube which is immersed in a low temperature solvent/liquid nitrogen slush bath whose temperature is measured with a thermocouple. The vapor pressure is then measured directly with a capacitance manometer. For lower pressures, a second technique which was called the thin-film infrared method (TFIR) was developed. It involves measuring the disappearance rate of a thin film of acetylene at a particular temperature. The spectra are then analyzed using previously determined extinction coefficient values, to determine the disappearance rate R (where R = delta n/delta t, the number of molecules that disappear per unit time). This can be related to the vapor pressure directly. This technique facilitates measurement of the lower temperatures and pressures. Both techniques have been calibrated using CO2, and have shown good agreement with the existing literature data.

  4. Effects of Chamber Pressure and Partial Pressure of Water Vapor on Secondary Drying in Lyophilization.

    PubMed

    Searles, James A; Aravapalli, Sridhar; Hodge, Cody

    2017-10-01

    Secondary drying is the final step of lyophilization before stoppering, during which water is desorbed from the product to yield the final moisture content. We studied how chamber pressure and partial pressure of water vapor during this step affected the time course of water content of aqueous solutions of polyvinylpyrrolidone (PVP) in glass vials. The total chamber pressure had no effect when the partial pressure of water vapor was very low. However, when the vapor phase contained a substantial fraction of water vapor, the PVP moisture content was much higher. We carried out dynamic vapor sorption experiments (DVS) to demonstrate that the higher PVP moisture content was a straightforward result of the higher water vapor content in the lyophilizer. The results highlight that the partial pressure of water vapor is extremely important during secondary drying in lyophilization, and that lower chamber pressure set points for secondary drying may sometimes be justified as a strategy for ensuring low partial pressure of water vapor, especially for lyophilizers that do not inject dry gas to control pressure. These findings have direct application for process transfers/scale ups from freeze-dryers that do not inject dry gas for pressure control to those that do, and vice versa.

  5. The Breathing Snowpack: Pressure-induced Vapor Flux of Temperate Snow

    NASA Astrophysics Data System (ADS)

    Drake, S. A.; Selker, J. S.; Higgins, C. W.

    2017-12-01

    As surface air pressure increases, hydrostatic compression of the air column forces atmospheric air into snowpack pore space. Likewise, as surface air pressure decreases, the atmospheric air column decompresses and saturated air exits the snow. Alternating influx and efflux of air can be thought of as a "breathing" process that produces an upward vapor flux when air above the snow is not saturated. The impact of pressure-induced vapor exchange is assumed to be small and is thus ignored in model parameterizations of surface processes over snow. Rationale for disregarding this process is that large amplitude pressure changes as caused by synoptic weather patterns are too infrequent to credibly impact vapor flux. The amplitude of high frequency pressure changes is assumed to be too small to affect vapor flux, however, the basis for this hypothesis relies on pressure measurements collected over an agricultural field (rather than snow). Resolution of the impact of pressure changes on vapor flux over seasonal cycles depends on an accurate representation of the magnitude of pressure changes caused by changes in wind as a function of the frequency of pressure changes. High precision in situ pressure measurements in a temperature snowpack allowed us to compute the spectra of pressure changes vs. wind forcing. Using a simplified model for vapor exchange we then computed the frequency of pressure changes that maximize vapor exchange. We examine and evaluate the seasonal impact of pressure-induced vapor exchange relative to other snow ablation processes.

  6. Statistics of pressure and pressure gradient in homogeneous isotropic turbulence

    NASA Technical Reports Server (NTRS)

    Gotoh, T.; Rogallo, R. S.

    1994-01-01

    The statistics of pressure and pressure gradient in stationary isotropic turbulence are measured within direct numerical simulations at low to moderate Reynolds numbers. It is found that the one-point pdf of the pressure is highly skewed and that the pdf of the pressure gradient is of stretched exponential form. The power spectrum of the pressure P(k) is found to be larger than the corresponding spectrum P(sub G)(k) computed from a Gaussian velocity field having the same energy spectrum as that of the DNS field. The ratio P(k)/P(sub G)(k), a measure of the pressure-field intermittence, grows with wavenumber and Reynolds number as -R(sub lambda)(exp 1/2)log(k/k(sub d)) for k less than k(sub d)/2 where k(sub d) is the Kolmogorov wavenumber. The Lagrangian correlations of pressure gradient and velocity are compared and the Lagrangian time scale of the pressure gradient is observed to be much shorter than that of the velocity.

  7. 46 CFR 154.445 - Design vapor pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.445 Section 154.445 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type B § 154.445 Design vapor pressure. If the surfaces of an independent tank type B are...

  8. 46 CFR 154.438 - Design vapor pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.438 Section 154.438 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.438 Design vapor pressure. (a) If the surface of an independent tank type A are...

  9. 46 CFR 154.436 - Design vapor pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Design vapor pressure. 154.436 Section 154.436 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Semi-Membrane Tanks § 154.436 Design vapor pressure....

  10. 46 CFR 154.419 - Design vapor pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Design vapor pressure. 154.419 Section 154.419 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.419 Design vapor pressure. The...

  11. 46 CFR 154.419 - Design vapor pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Design vapor pressure. 154.419 Section 154.419 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.419 Design vapor pressure. The...

  12. 46 CFR 154.426 - Design vapor pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Design vapor pressure. 154.426 Section 154.426 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Membrane Tanks § 154.426 Design vapor pressure. The...

  13. 46 CFR 154.419 - Design vapor pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Design vapor pressure. 154.419 Section 154.419 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.419 Design vapor pressure. The...

  14. 46 CFR 154.426 - Design vapor pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Design vapor pressure. 154.426 Section 154.426 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Membrane Tanks § 154.426 Design vapor pressure. The...

  15. 46 CFR 154.426 - Design vapor pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Design vapor pressure. 154.426 Section 154.426 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Membrane Tanks § 154.426 Design vapor pressure. The...

  16. 46 CFR 154.436 - Design vapor pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Design vapor pressure. 154.436 Section 154.436 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Semi-Membrane Tanks § 154.436 Design vapor pressure....

  17. 46 CFR 154.436 - Design vapor pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Design vapor pressure. 154.436 Section 154.436 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Semi-Membrane Tanks § 154.436 Design vapor pressure....

  18. Controlling the vapor pressure of a mercury lamp

    DOEpatents

    Grossman, Mark W.; George, William A.

    1988-01-01

    The invention described herein discloses a method and apparatus for controlling the Hg vapor pressure within a lamp. This is done by establishing and controlling two temperature zones within the lamp. One zone is colder than the other zone. The first zone is called the cold spot. By controlling the temperature of the cold spot, the Hg vapor pressure within the lamp is controlled. Likewise, by controlling the Hg vapor pressure of the lamp, the intensity and linewidth of the radiation emitted from the lamp is controlled.

  19. 46 CFR 154.436 - Design vapor pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.436 Section 154.436 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Semi-Membrane Tanks § 154.436 Design vapor pressure. The Po of a semi-membrane tank must not exceed 24.5 kPa...

  20. 46 CFR 154.419 - Design vapor pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.419 Section 154.419 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.419 Design vapor pressure. The Po of an integral tank must not exceed 24.5 kPa gauge (3.55...

  1. 46 CFR 154.426 - Design vapor pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.426 Section 154.426 Shipping... FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Membrane Tanks § 154.426 Design vapor pressure. The Po of a membrane tank must not exceed 24.5 kPa gauge (3.55...

  2. Controlling the vapor pressure of a mercury lamp

    DOEpatents

    Grossman, M.W.; George, W.A.

    1988-05-24

    The invention described herein discloses a method and apparatus for controlling the Hg vapor pressure within a lamp. This is done by establishing and controlling two temperature zones within the lamp. One zone is colder than the other zone. The first zone is called the cold spot. By controlling the temperature of the cold spot, the Hg vapor pressure within the lamp is controlled. Likewise, by controlling the Hg vapor pressure of the lamp, the intensity and linewidth of the radiation emitted from the lamp is controlled. 2 figs.

  3. Vapor-dominated zones within hydrothermal systems: evolution and natural state

    USGS Publications Warehouse

    Ingebritsen, S.E.; Sorey, M.L.

    1988-01-01

    Three conceptual models illustrate the range of hydrothermal systems in which vapor-dominated conditions are found. The first model (model I) represents a system with an extensive near-vaporstatic vapor-dominated zone and limited liquid throughflow and is analogous to systems such as The Geysers, California. Models II and III represent systems with significant liquid throughflow and include steam-heated discharge features at higher elevations and high-chloride springs at lower elevations connected to and fed by a single circulation system at depth. In model II, as in model I, the vapor-dominated zone has a near-vaporstatic vertical pressure gradient and is generally underpressured with respect to local hydrostatic pressure. The vapor-dominated zone in model III is quite different, in that phase separation takes place at pressures close to local hydrostatic and the overall pressure gradient is near hydrostatic. -from Authors

  4. Gasoline Reid Vapor Pressure

    EPA Pesticide Factsheets

    EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

  5. Apparatus of the Vapor-pressure Measurements for Natural Refrigerants

    NASA Astrophysics Data System (ADS)

    Higuchi, Satoru; Higashi, Yukihiro

    An apparatus for measuring the vapor-pressures was newly designed and constructed in order to make the basic thermodynamic properties for environmentally acceptable refrigerants clear. The temperature of sample fluid was measured with 100Ω platinum resistance thermometer calibrated against ITS-90 using a 25Ω standard platinum resistance thermometer. With respect to the pressure measurement, two kinds of presure transducer were adopted. One is a diaphragm semi-conductor strain pressure transducer with the uncertainty of ±0.09%. This pressure transducer was calibrated against quartz crystal pressure transducer with the uncertainty of ±0.01% after every series of experiments. Another is a quartz crystal pressure transducer with the uncertainty of ±0.01%. A quartz crystal pressure transducer was calibrated against the dead weight pressure gauge and barometer. The vapor-pressures for R-32, R-134a, R-290 (propane), R-600a (iso-butane) and n-pentane were measured in the temperature range between273.15 and 323.15K. As the results of vapor-pressure measurements, the reliability of the experimental apparatus as well as the reproducibility of the experimental data were confirmed. In addition, coefficients of Antoine vapor pressure equation were determined from the experimental data. Normal boiling points for environmentally acceptable refrigerants were also determined with high accuracy.

  6. 40 CFR 796.1950 - Vapor pressure.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to a wide variety of chemical types and structures, EPA has sponsored research and development work... Chemistry, 3:664-670 (1969). (3) Spencer, W.F. and Cliath, M.M. “Vapor Density and Apparent Vapor Pressure of Lindane,” Journal of Agricultural and Food Chemistry, 18:529-530 (1970). [50 FR 39252, Sept. 27...

  7. 40 CFR 796.1950 - Vapor pressure.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to a wide variety of chemical types and structures, EPA has sponsored research and development work... Chemistry, 3:664-670 (1969). (3) Spencer, W.F. and Cliath, M.M. “Vapor Density and Apparent Vapor Pressure of Lindane,” Journal of Agricultural and Food Chemistry, 18:529-530 (1970). [50 FR 39252, Sept. 27...

  8. 40 CFR 796.1950 - Vapor pressure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... to a wide variety of chemical types and structures, EPA has sponsored research and development work... Chemistry, 3:664-670 (1969). (3) Spencer, W.F. and Cliath, M.M. “Vapor Density and Apparent Vapor Pressure of Lindane,” Journal of Agricultural and Food Chemistry, 18:529-530 (1970). [50 FR 39252, Sept. 27...

  9. 40 CFR 796.1950 - Vapor pressure.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... to a wide variety of chemical types and structures, EPA has sponsored research and development work... Chemistry, 3:664-670 (1969). (3) Spencer, W.F. and Cliath, M.M. “Vapor Density and Apparent Vapor Pressure of Lindane,” Journal of Agricultural and Food Chemistry, 18:529-530 (1970). [50 FR 39252, Sept. 27...

  10. Gradient echo quantum memory in warm atomic vapor.

    PubMed

    Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M; Everett, Jesse L; Higginbottom, Daniel; Campbell, Geoff T; Lam, Ping Koy; Buchler, Ben C

    2013-11-11

    Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.

  11. Gradient Echo Quantum Memory in Warm Atomic Vapor

    PubMed Central

    Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M.; Everett, Jesse L.; Higginbottom, Daniel; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

    2013-01-01

    Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain. PMID:24300586

  12. Thermogravimetric study of vapor pressure of TATP synthesized without recrystallization.

    PubMed

    Mbah, Jonathan; Knott, Debra; Steward, Scott

    2014-11-01

    This study aims at characterizing the vapor pressure signatures generated by triacetone triperoxide (TATP) that was synthesized without recrystallization by thermogravimmetric analysis (TGA) for exploitation by standoff detection technologies of explosive devices. The thermal behavior of the nonrecrystallized sample was compared with reported values. Any phase change, melting point and decomposition identification were studied by differential scanning calorimeter. Vapor pressures were estimated by the Langmuir method of evaporation from an open surface in a vacuum. Vapor pressures of TATP at different temperatures were calculated using the linear logarithmic relationship obtained from benzoic acid reference standard. Sublimation of TATP was found to follow apparent zero-order kinetics and sublimes at steady rates at 298 K and above. While the enthalpy of sublimation found, 71.7 kJ mol(-1), is in agreement with reported values the vapor pressures deviated significantly. The differences in the vapor pressures behavior are attributable to the synthesis pathway chosen in this study. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Vapor Pressure of Antimony Triiodide

    DTIC Science & Technology

    2017-12-07

    function of inverse temperature ........................................................................................... 4 Fig. 3 Effective ∆Hvapor of...pressure on inverse -temperature with the slope of (∆Hvapor/R). One method of experimentally determining ∆Hvapor, therefore, is to measure the...equilibrium vapor pressure of any material as a function of inverse -temperature where the slope of the data can be used to directly determine ∆Hvapor

  14. Subatmospheric vapor pressures evaluated from internal-energy measurements

    NASA Astrophysics Data System (ADS)

    Duarte-Garza, H. A.; Magee, J. W.

    1997-01-01

    Vapor pressures were evaluated from measured internal-energy changes in the vapor+liquid two-phase region, Δ U (2). The method employed a thermodynamic relationship between the derivative quantity (ϖ U (2)/ϖ V) T and the vapor pressure ( p σ) and its temperature derivative (ϖ p/ϖ T)σ. This method was applied at temperatures between the triple point and the normal boiling point of three substances: 1,1,1,2-tetrafluoroethane (R134a), pentafluoroethane (R125), and difluoromethane (R32). Agreement with experimentally measured vapor pressures near the normal boiling point (101.325 kPa) was within the experimental uncertainty of approximately ±0.04 kPa (±0.04%). The method was applied to R134a to test the thermodynamic consistency of a published p-p-T equation of state with an equation for p σ for this substance. It was also applied to evaluate published p σ data which are in disagreement by more than their claimed uncertainty.

  15. A Simple Experiment for Determining Vapor Pressure and Enthalpy of Vaporization of Water.

    ERIC Educational Resources Information Center

    Levinson, Gerald S.

    1982-01-01

    Laboratory procedures, calculations, and sample results are described for a freshman chemistry experiment in which the Clausius-Clapeyron equation is introduced as a means of describing the variation of vapor pressure with temperature and for determining enthalpy of vaporization. (Author/SK)

  16. The self-similar turbulent flow of low-pressure water vapor

    NASA Astrophysics Data System (ADS)

    Konyukhov, V. K.; Stepanov, E. V.; Borisov, S. K.

    2018-05-01

    We studied turbulent flows of water vapor in a pipe connecting two closed vessels of equal volume. The vessel that served as a source of water vapor was filled with adsorbent in the form of corundum ceramic balls. These ceramic balls were used to obtain specific conditions to lower the vapor pressure in the source vessel that had been observed earlier. A second vessel, which served as a receiver, was empty of either air or vapor before each vapor sampling. The rate of the pressure increase in the receiver vessel was measured in a series of six samplings performed with high precision. The pressure reduction rate in the source vessel was found to be three times lower than the pressure growth rate in the receiver vessel. We found that the pressure growth rates in all of the adjacent pairs of samples could be arranged in a combination that appeared to be identical for all pairs, and this revealed the existence of a rather interesting and peculiar self-similarity law for the sampling processes under consideration.

  17. A technique to depress desflurane vapor pressure.

    PubMed

    Brosnan, Robert J; Pypendop, Bruno H

    2006-09-01

    To determine whether the vapor pressure of desflurane could be decreased by using a solvent to reduce the anesthetic molar fraction in a solution (Raoult's Law). We hypothesized that such an anesthetic mixture could produce anesthesia using a nonprecision vaporizer instead of an agent-specific, electronically controlled, temperature and pressure compensated vaporizer currently required for desflurane administration. One healthy adult female dog. Propylene glycol was used as a solvent for desflurane, and the physical characteristics of this mixture were evaluated at various molar concentrations and temperatures. Using a circle system with a breathing bag attached at the patient end and a mechanical ventilator to simulate respiration, an in-circuit, nonprecision vaporizer containing 40% desflurane and 60% propylene glycol achieved an 11.5% +/- 1.0% circuit desflurane concentration with a 5.2 +/- 0.4 (0 = off, 10 = maximum) vaporizer setting. This experiment was repeated with a dog attached to the breathing circuit under spontaneous ventilation with a fresh gas flow of 0.5 L minute(-1). Anesthesia was maintained for over 2 hours at a mean vaporizer setting of 6.2 +/- 0.4, yielding mean inspired and end-tidal desflurane concentrations of 8.7% +/- 0.5% and 7.9% +/- 0.7%, respectively. Rather than alter physical properties of vaporizers to suit a particular anesthetic agent, this study demonstrates that it is also possible to alter physical properties of anesthetic agents to suit a particular vaporizer. However, propylene glycol may not prove an ideal solvent for desflurane because of its instability in solution and substantial-positive deviation from Raoult's Law.

  18. Prospective Chemistry Teachers' Mental Models of Vapor Pressure

    ERIC Educational Resources Information Center

    Tumay, Halil

    2014-01-01

    The main purpose of this study was to identify prospective chemistry teachers' mental models of vapor pressure. The study involved 85 students in the Chemistry Teacher Training Department of a state university in Turkey. Participants' mental models of vapor pressure were explored using a concept test that involved qualitative comparison tasks.…

  19. 46 CFR 154.445 - Design vapor pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Design vapor pressure. 154.445 Section 154.445 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type B § 154.445 Design vapor...

  20. 46 CFR 154.445 - Design vapor pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Design vapor pressure. 154.445 Section 154.445 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type B § 154.445 Design vapor...

  1. 46 CFR 154.438 - Design vapor pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Design vapor pressure. 154.438 Section 154.438 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.438 Design vapor...

  2. 46 CFR 154.438 - Design vapor pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Design vapor pressure. 154.438 Section 154.438 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.438 Design vapor...

  3. 46 CFR 154.438 - Design vapor pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Design vapor pressure. 154.438 Section 154.438 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.438 Design vapor...

  4. 46 CFR 154.445 - Design vapor pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Design vapor pressure. 154.445 Section 154.445 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type B § 154.445 Design vapor...

  5. Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid

    ERIC Educational Resources Information Center

    Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent

    2007-01-01

    This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

  6. Determination of vapor pressure of low-volatility compounds using a method to obtain saturated vapor with coated capillary columns.

    PubMed

    Rittfeldt, L

    2001-06-01

    The vapor pressures of O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), O-isobutyl S-2-diethylaminoethyl methylphosphonothiolate (RVX), and 2,4-dinitrotoluene (2,4-DNT) were determined with the gas saturation method in temperatures ranging from -12 to 103 degrees C. The saturated vapor was generated using a fused-silica column coated with the compound. This column was placed in a gas chromatograph, and the vapor pressure was determined directly from the detector signal or by sampling on Tenax tubes that were subsequently analyzed. From the linear relationships obtained by plotting log P vs 1/T, the enthalpies of vaporization (deltaHvap) and the vapor pressures at selected temperatures were determined. The vapor pressure of VX at 25 degrees C was 0.110 Pa and the deltaHvap 77.9 kJ x mol(-1). The corresponding results for RVX were 0.082 Pa and 76.6 kJ x mol(-1). The vapor pressure of 2,4-DNT at 72 degrees C (melting point) was determined to 6.0 Pa, and the enthalpies of the solid and the liquid state were 94.2 and 75.3 kJ x mol(-1), respectively. Using capillary columns to generate saturated vapors has three major advantages: short equilibrium time, low consumption of sample, and safe handling of toxic compounds.

  7. Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface

    NASA Technical Reports Server (NTRS)

    Stewart, Mark E. M.

    2017-01-01

    This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

  8. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    PubMed

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  9. Vapor pressure and vapor fractionation of silicate melts of tektite composition

    USGS Publications Warehouse

    Walter, Louis S.; Carron, M.K.

    1964-01-01

    The total vapor pressure of Philippine tektite melts of approximately 70 per cent silica has been determined at temperatures ranging from 1500 to 2100??C. This pressure is 190 ?? 40 mm Hg at 1500??C, 450 ?? 50 mm at 1800??C and 850 ?? 70 mm at 2100?? C. Determinations were made by visually observing the temperature at which bubbles began to form at a constant low ambient pressure. By varying the ambient pressure, a boiling point curve was constructed. This curve differs from the equilibrium vapor pressure curve due to surface tension effects. This difference was evaluated by determining the equilibrium bubble size in the melt and calculating the pressure due to surface tension, assuming the latter to be 380 dyn/cm. The relative volatility from tektite melts of the oxides of Na, K, Fe, Al and Si has been determined as a function of temperature, total pressure arid roughly, of oxygen fugacity. The volatility of SiO2 is decreased and that of Na2O and K2O is increased in an oxygen-poor environment. Preliminary results indicate that volatilization at 2100??C under atmospheric pressure caused little or no change in the percentage Na2O and K2O. The ratio Fe3 Fe2 of the tektite is increased in ambient air at a pressure of 9 ?? 10-4 mm Hg (= 106.5 atm O2, partial pressure) at 2000??C. This suggests that tektites were formed either at lower oxygen pressures or that they are a product of incomplete oxidation of parent material with a still lower ferricferrous ratio. ?? 1964.

  10. Method and apparatus to measure vapor pressure in a flow system

    DOEpatents

    Grossman, Mark W.; Biblarz, Oscar

    1991-01-01

    The present invention is directed to a method for determining, by a condensation method, the vapor pressure of a material with a known vapor pressure versus temperature characteristic, in a flow system particularly in a mercury isotope enrichment process.

  11. Estimating enthalpy of vaporization from vapor pressure using Trouton's rule.

    PubMed

    MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad

    2007-04-15

    The enthalpy of vaporization of liquids and subcooled liquids at 298 K (delta H(VAP)) is an important parameter in environmental fate assessments that consider spatial and temporal variability in environmental conditions. It has been shown that delta H(VAP)P for non-hydrogen-bonding substances can be estimated from vapor pressure at 298 K (P(L)) using an empirically derived linear relationship. Here, we demonstrate that the relationship between delta H(VAP)and PL is consistent with Trouton's rule and the ClausiusClapeyron equation under the assumption that delta H(VAP) is linearly dependent on temperature between 298 K and the boiling point temperature. Our interpretation based on Trouton's rule substantiates the empirical relationship between delta H(VAP) degree and P(L) degrees for non-hydrogen-bonding chemicals with subcooled liquid vapor pressures ranging over 15 orders of magnitude. We apply the relationship between delta H(VAP) degrees and P(L) degrees to evaluate data reported in literature reviews for several important classes of semivolatile environmental contaminants, including polycyclic aromatic hydrocarbons, chlorobenzenes, polychlorinated biphenyls and polychlorinated dibenzo-dioxins and -furans and illustrate the temperature dependence of results from a multimedia model presented as a partitioning map. The uncertainty associated with estimating delta H(VAP)degrees from P(L) degrees using this relationship is acceptable for most environmental fate modeling of non-hydrogen-bonding semivolatile organic chemicals.

  12. Method and apparatus to measure vapor pressure in a flow system

    DOEpatents

    Grossman, M.W.; Biblarz, O.

    1991-10-15

    The present invention is directed to a method for determining, by a condensation method, the vapor pressure of a material with a known vapor pressure versus temperature characteristic, in a flow system particularly in a mercury isotope enrichment process. 2 figures.

  13. Pressure gradients fail to predict diffusio-osmosis

    NASA Astrophysics Data System (ADS)

    Liu, Yawei; Ganti, Raman; Frenkel, Daan

    2018-05-01

    We present numerical simulations of diffusio-osmotic flow, i.e. the fluid flow generated by a concentration gradient along a solid-fluid interface. In our study, we compare a number of distinct approaches that have been proposed for computing such flows and compare them with a reference calculation based on direct, non-equilibrium molecular dynamics simulations. As alternatives, we consider schemes that compute diffusio-osmotic flow from the gradient of the chemical potentials of the constituent species and from the gradient of the component of the pressure tensor parallel to the interface. We find that the approach based on treating chemical potential gradients as external forces acting on various species agrees with the direct simulations, thereby supporting the approach of Marbach et al (2017 J. Chem. Phys. 146 194701). In contrast, an approach based on computing the gradients of the microscopic pressure tensor does not reproduce the direct non-equilibrium results.

  14. Relationship between exercise pressure gradient and haemodynamic progression of aortic stenosis.

    PubMed

    Ringle, Anne; Levy, Franck; Ennezat, Pierre-Vladimir; Le Goffic, Caroline; Castel, Anne-Laure; Delelis, François; Menet, Aymeric; Malaquin, Dorothée; Graux, Pierre; Vincentelli, André; Tribouilloy, Christophe; Maréchaux, Sylvestre

    We hypothesized that large exercise-induced increases in aortic mean pressure gradient can predict haemodynamic progression during follow-up in asymptomatic patients with aortic stenosis. We retrospectively identified patients with asymptomatic moderate or severe aortic stenosis (aortic valve area<1.5cm 2 or<1cm 2 ) and normal ejection fraction, who underwent an exercise stress echocardiography at baseline with a normal exercise test and a resting echocardiography during follow-up. The relationship between exercise-induced increase in aortic mean pressure gradient and annualised changes in resting mean pressure gradient during follow-up was investigated. Fifty-five patients (mean age 66±15 years; 45% severe aortic stenosis) were included. Aortic mean pressure gradient significantly increased from rest to peak exercise (P<0.001). During a median follow-up of 1.6 [1.1-3.2] years, resting mean pressure gradient increased from 35±13mmHg to 48±16mmHg, P<0.0001. Median annualised change in resting mean pressure gradient during follow-up was 5 [2-11] mmHg. Exercise-induced increase in aortic mean pressure gradient did correlate with annualised changes in mean pressure gradient during follow-up (r=0.35, P=0.01). Hemodynamic progression of aortic stenosis was faster in patients with large exercise-induced increase in aortic mean pressure gradient (≥20mmHg) as compared to those with exercise-induced increase in aortic mean pressure gradient<20mmHg (median annualised increase in mean pressure gradient 19 [6-28] vs. 4 [2-10] mmHg/y respectively, P=0.002). Similar results were found in the subgroup of 30 patients with moderate aortic stenosis. Large exercise-induced increases in aortic mean pressure gradient correlate with haemodynamic progression of stenosis during follow-up in patients with asymptomatic aortic stenosis. Further studies are needed to fully establish the role of ESE in the decision-making process in comparison to other prognostic markers in asymptomatic

  15. Flow-related Right Ventricular - Pulmonary Arterial Pressure Gradients during Exercise.

    PubMed

    Wright, Stephen P; Opotowsky, Alexander R; Buchan, Tayler A; Esfandiari, Sam; Granton, John T; Goodman, Jack M; Mak, Susanna

    2018-06-06

    The assumption of equivalence between right ventricular and pulmonary arterial systolic pressure is fundamental to several assessments of right ventricular or pulmonary vascular hemodynamic function. Our aims were to 1) determine whether systolic pressure gradients develop across the right ventricular outflow tract in healthy adults during exercise, 2) examine the potential correlates of such gradients, and 3) consider the effect of such gradients on calculated indices of right ventricular function. Healthy untrained and endurance-trained adult volunteers were studied using right-heart catheterization at rest and during submaximal cycle ergometry. Right ventricular and pulmonary artery pressures were simultaneously transduced, and cardiac output was determined by thermodilution. Systolic pressures, peak and mean gradients, and indices of chamber, vascular, and valve function were analyzed offline. Summary data are reported as mean ± standard deviation or median [interquartile range]. No significant right ventricular outflow tract gradients were observed at rest (mean gradient = 4 [3-5] mmHg), and calculated effective orifice area was 3.6±1.0 cm2. Right ventricular systolic pressure increases during exercise were greater than that of pulmonary artery systolic pressure. Accordingly, mean gradients developed during light exercise (8 [7-9] mmHg) and increased during moderate exercise (12 [9-14] mmHg, p < 0.001). The magnitude of the mean gradient was linearly related to cardiac output (r2 = 0.70, p < 0.001). In healthy adults without pulmonic stenosis, systolic pressure gradients develop during exercise, and the magnitude is related to blood flow rate.

  16. 46 CFR 153.372 - Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Gauges and vapor return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia). 153.372 Section 153.372 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... return for cargo vapor pressures exceeding 100 kPa (approx. 14.7 psia). When table 1 references this...

  17. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... TREATMENT, STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1054 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief...

  18. Water-vapor pressure control in a volume

    NASA Technical Reports Server (NTRS)

    Scialdone, J. J.

    1978-01-01

    The variation with time of the partial pressure of water in a volume that has openings to the outside environment and includes vapor sources was evaluated as a function of the purging flow and its vapor content. Experimental tests to estimate the diffusion of ambient humidity through openings and to validate calculated results were included. The purging flows required to produce and maintain a certain humidity in shipping containers, storage rooms, and clean rooms can be estimated with the relationship developed here. These purging flows are necessary to prevent the contamination, degradation, and other effects of water vapor on the systems inside these volumes.

  19. Optimal disturbances in boundary layers subject to streamwise pressure gradient

    NASA Technical Reports Server (NTRS)

    Ashpis, David E.; Tumin, Anatoli

    2003-01-01

    An analysis of the optimal non-modal growth of perturbations in a boundary layer in the presence of a streamwise pressure gradient is presented. The analysis is based on PSE equations for an incompressible fluid. Examples with Falkner-Scan profiles indicate that a favorable pressure gradient decreases the non-modal growth, while an unfavorable pressure gradient leads to an increase of the amplification. It is suggested that the transient growth mechanism be utilized to choose optimal parameters of tripping elements on a low-pressure turbine (LPT) airfoil. As an example, a boundary layer flow with a streamwise pressure gradient corresponding to the pressure distribution over a LPT airfoil is considered. It is shown that there is an optimal spacing of the tripping elements and that the transient growth effect depends on the starting point.

  20. The Oxidation Rate of SiC in High Pressure Water Vapor Environments

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Robinson, R. Craig

    1999-01-01

    CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accounting for volatility of silica in water vapor, the parabolic rate constants for Sic in water vapor pressures of 0.7, 1.8 and 3.1 atm were determined. The dependence of the parabolic rate constant on the water vapor pressure yielded a power law exponent of one. Silica growth on Sic is therefore limited by transport of molecular water vapor through the silica scale.

  1. Prediction of the vapor pressure and vaporization enthalpy of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids.

    PubMed

    Diedenhofen, Michael; Klamt, Andreas; Marsh, Kenneth; Schäfer, Ansgar

    2007-09-07

    The vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids have been predicted with two different approaches using the COSMO-RS method and quantum chemical gas phase calculations. While the calculated enthalpies are in good agreement with the experimental data, COSMO-RS seems to underestimate the vapor pressures by roughly 0.5-4 log units dependent on the IL and approach used.

  2. A reference data set for validating vapor pressure measurement techniques: homologous series of polyethylene glycols

    NASA Astrophysics Data System (ADS)

    Krieger, Ulrich K.; Siegrist, Franziska; Marcolli, Claudia; Emanuelsson, Eva U.; Gøbel, Freya M.; Bilde, Merete; Marsh, Aleksandra; Reid, Jonathan P.; Huisman, Andrew J.; Riipinen, Ilona; Hyttinen, Noora; Myllys, Nanna; Kurtén, Theo; Bannan, Thomas; Percival, Carl J.; Topping, David

    2018-01-01

    To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well-established saturation vapor pressures. However, vapor pressures of semivolatile and low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of 2. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem, we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H - (O - CH2 - CH2)n - OH) for n = 3 to n = 8 ranging in vapor pressure at 298 K from 10-7 to 5×10-2 Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows outlying data to be rejected more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressure values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass

  3. Evaporation rate and vapor pressure of selected polymeric lubricating oils.

    NASA Technical Reports Server (NTRS)

    Gardos, M. N.

    1973-01-01

    A recently developed ultrahigh-vacuum quartz spring mass sorption microbalance has been utilized to measure the evaporation rates of several low-volatility polymeric lubricating oils at various temperatures. The evaporation rates are used to calculate the vapor pressures by the Langmuir equation. A method is presented to accurately estimate extended temperature range evaporation rate and vapor pressure data for polymeric oils, incorporating appropriate corrections for the increases in molecular weight and the change in volatility of the progressively evaporating polymer fractions. The logarithms of the calculated data appear to follow linear relationships within the test temperature ranges, when plotted versus 1000/T. These functions and the observed effusion characteristics of the fluids on progressive volatilization are useful in estimating evaporation rate and vapor pressure changes on evaporative depletion.

  4. Fifty shades of gradients: does the pressure gradient in venous sinus stenting for idiopathic intracranial hypertension matter? A systematic review.

    PubMed

    McDougall, Cameron M; Ban, Vin Shen; Beecher, Jeffrey; Pride, Lee; Welch, Babu G

    2018-03-02

    OBJECTIVE The role of venous sinus stenting (VSS) for idiopathic intracranial hypertension (IIH) is not well understood. The aim of this systematic review is to attempt to identify subsets of patients with IIH who will benefit from VSS based on the pressure gradients of their venous sinus stenosis. METHODS MEDLINE/PubMed was searched for studies reporting venous pressure gradients across the stenotic segment of the venous sinus, pre- and post-stent pressure gradients, and clinical outcomes after VSS. Findings are reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. RESULTS From 32 eligible studies, a total of 186 patients were included in the analysis. Patients who had favorable outcomes had higher mean pressure gradients (22.8 ± 11.5 mm Hg vs 17.4 ± 8.0 mm Hg, p = 0.033) and higher changes in pressure gradients after stent placement (19.4 ± 10.0 mm Hg vs 12.0 ± 6.0 mm Hg, p = 0.006) compared with those with unfavorable outcomes. The post-stent pressure gradients between the 2 groups were not significantly different (2.8 ± 4.0 mm Hg vs 2.7 ± 2.0 mm Hg, p = 0.934). In a multivariate stepwise logistic regression controlling for age, sex, body mass index, CSF opening pressure, pre-stent pressure gradient, and post-stent pressure gradient, the change in pressure gradient with stent placement was found to be an independent predictor of favorable outcome (p = 0.028). Using a pressure gradient of 21 as a cutoff, 81/86 (94.2%) of patients with a gradient > 21 achieved favorable outcomes, compared with 82/100 (82.0%) of patients with a gradient ≤ 21 (p = 0.022). CONCLUSIONS There appears to be a relationship between the pressure gradient of venous sinus stenosis and the success of VSS in IIH. A randomized controlled trial would help elucidate this relationship and potentially guide patient selection.

  5. An Indirect Method for Vapor Pressure and Phase Change Enthalpy Determination by Thermogravimetry

    NASA Astrophysics Data System (ADS)

    Giani, Samuele; Riesen, Rudolf; Schawe, Jürgen E. K.

    2018-07-01

    Vapor pressure is a fundamental property of a pure substance. This property is the pressure of a compound's vapor in thermodynamic equilibrium with its condensed phase (solid or liquid). When phase equilibrium condition is met, phase coexistence of a pure substance involves a continuum interplay of vaporization or sublimation to gas and condensation back to their liquid or solid form, respectively. Thermogravimetric analysis (TGA) techniques are based on mass loss determination and are well suited for the study of such phenomena. In this work, it is shown that TGA method using a reference substance is a suitable technique for vapor pressure determination. This method is easy and fast because it involves a series of isothermal segments. In contrast to original Knudsen's approach, where the use of high vacuum is mandatory, adopting the proposed method a given experimental setup is calibrated under ambient pressure conditions. The theoretical framework of this method is based on a generalization of Langmuir equation of free evaporation: The real strength of the proposed method is the ability to determine the vapor pressure independently of the molecular mass of the vapor. A demonstration of this method has been performed using the Clausius-Clapeyron equation of state to derive the working equation. This algorithm, however, is adaptive and admits the use of other equations of state. The results of a series of experiments with organic molecules indicate that the average difference of the measured and the literature vapor pressure amounts to about 5 %. Vapor pressure determined in this study spans from few mPa up to several kPa. Once the p versus T diagram is obtained, phase transition enthalpy can additionally be calculated from the data.

  6. Optimal Disturbances in Boundary Layers Subject to Streamwise Pressure Gradient

    NASA Technical Reports Server (NTRS)

    Ashpis, David E.; Tumin, Anatoli

    2003-01-01

    An analysis of the non-modal growth of perturbations in a boundary layer in the presence of a streamwise pressure gradient is presented. The analysis is based on PSE equations for an incompressible fluid. Examples with Falkner- Skan profiles indicate that a favorable pressure gradient decreases the non-modal growth while an unfavorable pressure gradient leads to an increase of the amplification. It is suggested that the transient growth mechanism be utilized to choose optimal parameters of tripping elements on a low-pressure turbine (LPT) airfoil. As an example, a boundary-layer flow with a streamwise pressure gradient corresponding to the pressure distribution over a LPT airfoil is considered. It is shown that there is an optimal spacing of the tripping elements and that the transient growth effect depends on the starting point. The amplification is found to be small at the LPT s very low Reynolds numbers, but there is a possibility to enhance the transient energy growth by means of wall cooling.

  7. Pluto's atmosphere - Models based on refraction, inversion, and vapor-pressure equilibrium

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.

    1989-01-01

    Viking spacecraft radio-occultation measurements indicate that, irrespective of substantial differences, the polar ice cap regions on Mars have inversions similar to those of Pluto, and may also share vapor pressure equilibrium characteristics at the surface. This temperature-inversion phenomenon occurs in a near-surface boundary layer; surface pressure-temperature may correspond to the vapor-pressure equilibrium with CH4 ice, or the temperature may be slightly higher to match the value derived from IRAS data.

  8. How important are internal temperature gradients in french straws during freezing of bovine sperm in nitrogen vapor?

    PubMed

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

    2013-01-01

    The subject of present work was to predict internal temperature gradients developed during freezing of bovine sperm diluted in extender, packaged in 0.5 ml French plastic straws and suspended in static liquid nitrogen vapor at -100 degree C. For this purpose, a mathematical heat transfer model previously developed to predict freezing times (phase change was considered) of semen/extender packaged in straw was extended to predict internal temperature gradients during the cooling/freezing process. Results showed maximum temperature differences between the centre and the periphery of semen/extender "liquid" column was 1.5 degree C for an external heat transfer coefficient, h = 15 W per (m(2) K), and only 0.5 degree C for h = 5 W per (m(2) K). It is concluded that if a thermocouple wire were inserted in a 0.5 ml plastic straw to monitor the freezing process in nitrogen vapor, its radial position would have little importance since expected internal gradients may be safely neglected. This finding facilitates the interpretation of freezing rates in 0.5 ml plastic straws immersed in nitrogen vapor over liquid nitrogen, a widely used method for cryopreservation of bovine spermatozoa.

  9. Bridgman-type apparatus for the study of growth-property relationships - Arsenic vapor pressure-GaAs property relationship

    NASA Technical Reports Server (NTRS)

    Parsey, J. M.; Nanishi, Y.; Lagowski, J.; Gatos, H. C.

    1982-01-01

    A precision Bridgman-type apparatus is described which was designed and constructed for the investigation of relationships between crystal growth parameters and the properties of GaAs crystals. Several key features of the system are highlighted, such as the use of a heat pipe for precise arsenic vapor pressure control and seeding without the presence of a viewing window. Pertinent growth parameters, such as arsenic source temperature, thermal gradients in the growing crystal and in the melt, and the macroscopic growth velocity can be independently controlled. During operation, thermal stability better than + or - 0.02 C is realized; thermal gradients can be varied up to 30 C/cm in the crystal region, and up to 20 C/cm in the melt region; the macroscopic growth velocity can be varied from 50 microns/hr to 6.0 cm/hr. It was found that the density of dislocations depends critically on As partial pressure; and essentially dislocation-free, undoped, crystals were grown under As pressure precisely controlled by an As source maintained at 617 C. The free carrier concentration varied with As pressure variations. This variation in free carrier concentration was found to be associated with variations in the compensation ratio rather than with standard segregation phenomena.

  10. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in...

  11. A survey and new measurements of ice vapor pressure at temperatures between 170 and 250K

    NASA Technical Reports Server (NTRS)

    Marti, James; Mauersberger, Konrad

    1993-01-01

    New measurements of ice vapor pressures at temperatures between 170 and 250 K are presented and published vapor pressure data are summarized. An empirical vapor pressure equation was derived and allows prediction of vapor pressures between 170 k and the triple point of water with an accuracy of approximately 2 percent. Predictions obtained agree, within experimental uncertainty, with the most reliable equation derived from thermodynamic principles.

  12. Preconcentrator with high volume chiller for high vapor pressure particle detection

    DOEpatents

    Linker, Kevin L

    2013-10-22

    Apparatus and method for collecting particles of both high and low vapor pressure target materials entrained in a large volume sample gas stream. Large volume active cooling provides a cold air supply which is mixed with the sample gas stream to reduce the vapor pressure of the particles. In embodiments, a chiller cools air from ambient conditions to 0-15.degree. C. with the volumetric flow rate of the cold air supply being at least equal to the volumetric flow rate of the sample gas stream. In further embodiments an adsorption media is heated in at least two stages, a first of which is below a threshold temperature at which decomposition products of the high vapor pressure particle are generated.

  13. Accurate pressure gradient calculations in hydrostatic atmospheric models

    NASA Technical Reports Server (NTRS)

    Carroll, John J.; Mendez-Nunez, Luis R.; Tanrikulu, Saffet

    1987-01-01

    A method for the accurate calculation of the horizontal pressure gradient acceleration in hydrostatic atmospheric models is presented which is especially useful in situations where the isothermal surfaces are not parallel to the vertical coordinate surfaces. The present method is shown to be exact if the potential temperature lapse rate is constant between the vertical pressure integration limits. The technique is applied to both the integration of the hydrostatic equation and the computation of the slope correction term in the horizontal pressure gradient. A fixed vertical grid and a dynamic grid defined by the significant levels in the vertical temperature distribution are employed.

  14. Large-eddy simulations of adverse pressure gradient turbulent boundary layers

    NASA Astrophysics Data System (ADS)

    Bobke, Alexandra; Vinuesa, Ricardo; Örlü, Ramis; Schlatter, Philipp

    2016-04-01

    Adverse pressure-gradient (APG) turbulent boundary layers (TBL) are studied by performing well-resolved large-eddy simulations. The pressure gradient is imposed by defining the free-stream velocity distribution with the description of a power law. Different inflow conditions, box sizes and upper boundary conditions are tested in order to determine the final set-up. The statistics of turbulent boundary layers with two different power-law coefficients and thus magnitudes of adverse pressure gradients are then compared to zero pressure-gradient (ZPG) data. The effect of the APG on TBLs is manifested in the mean flow through a much more prominent wake region and in the Reynolds stresses through the existence of an outer peak. The pre-multiplied energy budgets show that more energy is transported from the near-wall region to farther away from the wall.

  15. VAPOR PRESSURE ISOTOPE EFFECTS IN THE MEASUREMENT OF ENVIRONMENTAL TRITIUM SAMPLES.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kuhne, W.

    2012-12-03

    Standard procedures for the measurement of tritium in water samples often require distillation of an appropriate sample aliquot. This distillation process may result in a fractionation of tritiated water and regular light water due to the vapor pressure isotope effect, introducing either a bias or an additional contribution to the total tritium measurement uncertainty. The magnitude of the vapor pressure isotope effect is characterized as functions of the amount of water distilled from the sample aliquot and the heat settings for the distillation process. The tritium concentration in the distillate is higher than the tritium concentration in the sample earlymore » in the distillation process, it then sharply decreases due to the vapor pressure isotope effect and becomes lower than the tritium concentration in the sample, until the high tritium concentration retained in the boiling flask is evaporated at the end of the process. At that time, the tritium concentration in the distillate again overestimates the sample tritium concentration. The vapor pressure isotope effect is more pronounced the slower the evaporation and distillation process is conducted; a lower heat setting during the evaporation of the sample results in a larger bias in the tritium measurement. The experimental setup used and the fact that the current study allowed for an investigation of the relative change in vapor pressure isotope effect in the course of the distillation process distinguish it from and extend previously published measurements. The separation factor as a quantitative measure of the vapor pressure isotope effect is found to assume values of 1.034 {+-} 0.033, 1.052 {+-} 0.025, and 1.066 {+-} 0.037, depending on the vigor of the boiling process during distillation of the sample. A lower heat setting in the experimental setup, and therefore a less vigorous boiling process, results in a larger value for the separation factor. For a tritium measurement in water samples, this implies

  16. Measuring Vapor Pressure with an Isoteniscope: A Hands-on Introduction to Thermodynamic Concepts

    ERIC Educational Resources Information Center

    Chen, Wenqian; Haslam, Andrew J.; Macey, Andrew; Shah, Umang V.; Brechtelsbauer, Clemens

    2016-01-01

    Characterization of the vapor pressure of a volatile liquid or azeotropic mixture, and its fluid phase diagram, can be achieved with an isoteniscope and an industrial grade digital pressure sensor using the experimental method reported in this study. We describe vapor-pressure measurements of acetone and n-hexane and their azeotrope, and how the…

  17. Controlling Vapor Pressure In Hanging-Drop Crystallization

    NASA Technical Reports Server (NTRS)

    Carter, Daniel C.; Smith, Robbie

    1988-01-01

    Rate of evaporation adjusted to produce larger crystals. Device helps to control vapor pressure of water and other solvents in vicinity of hanging drop of solution containing dissolved enzyme protein. Well of porous frit (sintered glass) holds solution in proximity to drop of solution containing protein or enzyme. Vapor from solution in frit controls evaporation of solvent from drop to control precipitation of protein or enzyme. With device, rate of nucleation limited to decrease number and increase size (and perhaps quality) of crystals - large crystals of higher quality needed for x-ray diffraction studies of macromolecules.

  18. Pressure Gradient Effects on Hypersonic Cavity Flow Heating

    NASA Technical Reports Server (NTRS)

    Everhart, Joel L.; Alter, Stephen J.; Merski, N. Ronald; Wood, William A.; Prabhu, Ramadas K.

    2006-01-01

    The effect of a pressure gradient on the local heating disturbance of rectangular cavities tested at hypersonic freestream conditions has been globally assessed using the two-color phosphor thermography method. These experiments were conducted in the Langley 31-Inch Mach 10 Tunnel and were initiated in support of the Space Shuttle Return-To-Flight Program. Two blunted-nose test surface geometries were developed, including an expansion plate test surface with nearly constant negative pressure gradient and a flat plate surface with nearly zero pressure gradient. The test surface designs and flow characterizations were performed using two-dimensional laminar computational methods, while the experimental boundary layer state conditions were inferred using the measured heating distributions. Three-dimensional computational predictions of the entire model geometry were used as a check on the design process. Both open-flow and closed-flow cavities were tested on each test surface. The cavity design parameters and the test condition matrix were established using the computational predictions. Preliminary conclusions based on an analysis of only the cavity centerline data indicate that the presence of the pressure gradient did not alter the open cavity heating for laminar-entry/laminar-exit flows, but did raise the average floor heating for closed cavities. The results of these risk-reduction studies will be used to formulate a heating assessment of potential damage scenarios occurring during future Space Shuttle flights.

  19. Pressure Gradient Effects on Hypersonic Cavity Flow Heating

    NASA Technical Reports Server (NTRS)

    Everhart, Joel L.; Alter, Stephen J.; Merski, N. Ronald; Wood, William A.; Prabhu, Ramdas K.

    2007-01-01

    The effect of a pressure gradient on the local heating disturbance of rectangular cavities tested at hypersonic freestream conditions has been globally assessed using the two-color phosphor thermography method. These experiments were conducted in the Langley 31-Inch Mach 10 Tunnel and were initiated in support of the Space Shuttle Return-To-Flight Program. Two blunted-nose test surface geometries were developed, including an expansion plate test surface with nearly constant negative pressure gradient and a flat plate surface with nearly zero pressure gradient. The test surface designs and flow characterizations were performed using two-dimensional laminar computational methods, while the experimental boundary layer state conditions were inferred using the measured heating distributions. Three-dimensional computational predictions of the entire model geometry were used as a check on the design process. Both open-flow and closed-flow cavities were tested on each test surface. The cavity design parameters and the test condition matrix were established using the computational predictions. Preliminary conclusions based on an analysis of only the cavity centerline data indicate that the presence of the pressure gradient did not alter the open cavity heating for laminar-entry/laminar-exit flows, but did raise the average floor heating for closed cavities. The results of these risk-reduction studies will be used to formulate a heating assessment of potential damage scenarios occurring during future Space Shuttle flights.

  20. Temperature dependences of saturated vapor pressure and the enthalpy of vaporization of n-pentyl esters of dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Portnova, S. V.; Krasnykh, E. L.; Levanova, S. V.

    2016-05-01

    The saturated vapor pressures and enthalpies of vaporization of n-pentyl esters of linear C2-C6 dicarboxylic acids are determined by the transpiration method in the temperature range of 309.2-361.2 K. The dependences of enthalpies of vaporization on the number of carbon atoms in the molecule and on the retention indices have been determined. The predictive capabilities of the existing calculation schemes for estimation of enthalpy of vaporization of the studied compounds have been analyzed.

  1. Acoustic waves in gases with strong pressure gradients

    NASA Technical Reports Server (NTRS)

    Zorumski, William E.

    1989-01-01

    The effect of strong pressure gradients on the acoustic modes (standing waves) of a rectangular cavity is investigated analytically. When the cavity response is represented by a sum of modes, each mode is found to have two resonant frequencies. The lower frequency is near the Viaesaela-Brundt frequency, which characterizes the buoyant effect, and the higher frequency is above the ordinary acoustic resonance frequency. This finding shows that the propagation velocity of the acoustic waves is increased due to the pressure gradient effect.

  2. Low temperature measurement of the vapor pressures of planetary molecules

    NASA Technical Reports Server (NTRS)

    Kraus, George F.

    1989-01-01

    Interpretation of planetary observations and proper modeling of planetary atmospheres are critically upon accurate laboratory data for the chemical and physical properties of the constitutes of the atmospheres. It is important that these data are taken over the appropriate range of parameters such as temperature, pressure, and composition. Availability of accurate, laboratory data for vapor pressures and equilibrium constants of condensed species at low temperatures is essential for photochemical and cloud models of the atmospheres of the outer planets. In the absence of such data, modelers have no choice but to assume values based on an educated guess. In those cases where higher temperature data are available, a standard procedure is to extrapolate these points to the lower temperatures using the Clausius-Clapeyron equation. Last summer the vapor pressures of acetylene (C2H2) hydrogen cyanide (HCN), and cyanoacetylene (HC3N) was measured using two different methods. At the higher temperatures 1 torr and 10 torr capacitance manometers were used. To measure very low pressures, a technique was used which is based on the infrared absorption of thin film (TFIR). This summer the vapor pressure of acetylene was measured the TFIR method. The vapor pressure of hydrogen sulfide (H2S) was measured using capacitance manometers. Results for H2O agree with literature data over the common range of temperature. At the lower temperatures the data lie slightly below the values predicted by extrapolation of the Clausius-Clapeyron equation. Thin film infrared (TFIR) data for acetylene lie significantly below the values predicted by extrapolation. It is hoped to bridge the gap between the low end of the CM data and the upper end of the TFIR data in the future using a new spinning rotor gauge.

  3. Determination of vapor pressures for nonpolar and semipolar organic compounds from gas chromatographic retention data

    USGS Publications Warehouse

    Hinckley, D.A.; Bidleman, T.F.; Foreman, W.T.; Tuschall, J.R.

    1990-01-01

    Vapor pressures for nonpolar and moderately polar organochlorine, pyrethroid, and organophosphate insecticides, phthalate esters, and organophosphate flame retardants were determined by capillary gas chromatography (GC). Organochlorines and polycyclic aromatic hydrocarbons with known liquid-phase vapor pressures (P??L) (standard compounds) were chromatographed along with two reference compounds n-C20 (elcosane) and p,p???-DDT on a 1.0-m-long poly(dimethylsiloxane) bonded-phase (BP-1) column to determine their vapor pressures by GC (P??GC). A plot of log P??L vs log P??GC for standard compounds was made to establish a correlation between measured and literature values, and this correlation was then used to compute P??L of test compounds from their measured P??GC. P??L of seven major components of technical chlordane, endosulfan and its metabolites, ??-hexachlorocyclohexane, mirex, and two components of technical toxaphene were determined by GC. This method provides vapor pressures within a factor of 2 of average literature values for nonpolar compounds, similar to reported interlaboratory precisions of vapor pressure determinations. GC tends to overestimate vapor pressures of moderately polar compounds. ?? 1990 American Chemical Society.

  4. Compressed liquid densities, saturated liquid densities, and vapor pressures of 1,1-difluoroethane

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Defibaugh, D.R.; Morrison, G.

    1996-05-01

    The compressed liquid densities and vapor pressures of 1,1-difluoroethane (HFC-152a) have been measured, correlated, and compared with other data. The liquid densities were measured with a combined standard uncertainty of {+-}0.05% using a vibrating tube densimeter over a temperature range of 243 K to 371 K and at pressures from near the saturated vapor pressure to 6,500 kPa; thus the data extend nearly to the critical point ({Tc} = 386.41 K and P{sub c} = 4514.7 kPa). The vapor pressures were measured with a combined standard uncertainty of {+-}0.02% using a stainless steel ebulliometer in the temperature range from 280more » K to 335 K. Saturated liquid densities were calculated by extrapolating the compressed liquid isotherms to the saturation pressure.« less

  5. Impact vaporization: Late time phenomena from experiments

    NASA Technical Reports Server (NTRS)

    Schultz, P. H.; Gault, D. E.

    1987-01-01

    While simple airflow produced by the outward movement of the ejecta curtain can be scaled to large dimensions, the interaction between an impact-vaporized component and the ejecta curtain is more complicated. The goal of these experiments was to examine such interaction in a real system involving crater growth, ejection of material, two phased mixtures of gas and dust, and strong pressure gradients. The results will be complemented by theoretical studies at laboratory scales in order to separate the various parameters for planetary scale processes. These experiments prompt, however, the following conclusions that may have relevance at broader scales. First, under near vacuum or low atmospheric pressures, an expanding vapor cloud scours the surrounding surface in advance of arriving ejecta. Second, the effect of early-time vaporization is relatively unimportant at late-times. Third, the overpressure created within the crater cavity by significant vaporization results in increased cratering efficiency and larger aspect ratios.

  6. Investigation of local evaporation flux and vapor-phase pressure at an evaporative droplet interface.

    PubMed

    Duan, Fei; Ward, C A

    2009-07-07

    In the steady-state experiments of water droplet evaporation, when the throat was heating at a stainless steel conical funnel, the interfacial liquid temperature was found to increase parabolically from the center line to the rim of the funnel with the global vapor-phase pressure at around 600 Pa. The energy conservation analysis at the interface indicates that the energy required for evaporation is maintained by thermal conduction to the interface from the liquid and vapor phases, thermocapillary convection at interface, and the viscous dissipation globally and locally. The local evaporation flux increases from the center line to the periphery as a result of multiple effects of energy transport at the interface. The local vapor-phase pressure predicted from statistical rate theory (SRT) is also found to increase monotonically toward the interface edge from the center line. However, the average value of the local vapor-phase pressures is in agreement with the measured global vapor-phase pressure within the measured error bar.

  7. Pressure gradient induced generation of microbubbles

    NASA Astrophysics Data System (ADS)

    Evangelio, Alvaro; Campo-Cortes, Francisco; Gordillo, Jose Manuel

    2015-11-01

    It is well known that the controlled production of monodisperse bubbles possesses uncountable applications in medicine, pharmacy and industry. Here we provide with a detailed physical description of the bubble formation processes taking place in a type of flow where the liquid pressure gradient can be straightforwardly controlled. In our experiments, a gas flow rate discharges through a cylindrical needle into a pressurized chamber. The pressure gradient created from the exit of the injection needle towards the entrance of a extraction duct promotes the stretching of the gas ligament downstream. In our analysis, which is supported by an exhaustive experimental study in which the liquid viscosity is varied by three orders of magnitude, different regimes can be distinguished depending mainly on the Reynolds number. Through our physical modeling, we provide closed expressions for both the bubbling frequencies and for the bubble diameters as well as the conditions under which a monodisperse generation is obtained in all regimes found. The excellent agreement between our expressions and the experimental data fully validates our physical modeling.

  8. Evolution of a Planar Wake in Adverse Pressure Gradient

    NASA Technical Reports Server (NTRS)

    Driver, David M.; Mateer, George G.

    2016-01-01

    In the interest of improving the predictability of high-lift systems at maximum lift conditions, a series of fundamental experiments were conducted to study the effects of adverse pressure gradient on a wake flow. Mean and fluctuating velocities were measured with a two-component laser-Doppler velocimeter. Data were obtained for several cases of adverse pressure gradient, producing flows ranging from no reversed flow to massively reversed flow. While the turbulent Reynolds stresses increase with increasing size of the reversed flow region, the gradient of Reynolds stress does not. Computations using various turbulence models were unable to reproduce the reversed flow.

  9. A Study of Wake Development and Structure in Constant Pressure Gradients

    NASA Technical Reports Server (NTRS)

    Thomas, Flint O.; Nelson, R. C.; Liu, Xiaofeng

    2000-01-01

    Motivated by the application to high-lift aerodynamics for commercial transport aircraft, a systematic investigation into the response of symmetric/asymmetric planar turbulent wake development to constant adverse, zero, and favorable pressure gradients has been conducted. The experiments are performed at a Reynolds number of 2.4 million based on the chord of the wake generator. A unique feature of this wake study is that the pressure gradients imposed on the wake flow field are held constant. The experimental measurements involve both conventional LDV and hot wire flow field surveys of mean and turbulent quantities including the turbulent kinetic energy budget. In addition, similarity analysis and numerical simulation have also been conducted for this wake study. A focus of the research has been to isolate the effects of both pressure gradient and initial wake asymmetry on the wake development. Experimental results reveal that the pressure gradient has a tremendous influence on the wake development, despite the relatively modest pressure gradients imposed. For a given pressure gradient, the development of an initially asymmetric wake is different from the initially symmetric wake. An explicit similarity solution for the shape parameters of the symmetric wake is obtained and agrees with the experimental results. The turbulent kinetic energy budget measurements of the symmetric wake demonstrate that except for the convection term, the imposed pressure gradient does not change the fundamental flow physics of turbulent kinetic energy transport. Based on the turbulent kinetic energy budget measurements, an approach to correct the bias error associated with the notoriously difficult dissipation estimate is proposed and validated through the comparison of the experimental estimate with a direct numerical simulation result.

  10. DSMC simulations of vapor transport toward development of the lithium vapor box divertor concept

    NASA Astrophysics Data System (ADS)

    Jagoe, Christopher; Schwartz, Jacob; Goldston, Robert

    2016-10-01

    The lithium vapor divertor box concept attempts to achieve volumetric dissipation of the high heat efflux from a fusion power system. The vapor extracts the heat of the incoming plasma by ionization and radiation, while remaining localized in the vapor box due to differential pumping based on rapid condensation. Preliminary calculations with lithium vapor at densities appropriate for an NSTX-U-scale machine give Knudsen numbers between 0.01 and 1, outside both the range of continuum fluid dynamics and of collisionless Monte Carlo. The direct-simulation Monte Carlo (DSMC) method, however, can simulate rarefied gas flows in this regime. Using the solver contained in the OpenFOAM package, pressure-driven flows of water vapor will be analyzed. The use of water vapor in the relevant range of Knudsen number allows for a flexible similarity experiment to verify the reliability of the code before moving to tests with lithium. The simulation geometry consists of chains of boxes on a temperature gradient, connected by slots with widths that are a representative fraction of the dimensions of the box. We expect choked flow, sonic shocks, and order-of-magnitude pressure and density drops from box to box, but this expectation will be tested in the simulation and then experiment. This work is supported by the Princeton Environmental Institute.

  11. Quantifying Dynamic Changes in Plantar Pressure Gradient in Diabetics with Peripheral Neuropathy.

    PubMed

    Lung, Chi-Wen; Hsiao-Wecksler, Elizabeth T; Burns, Stephanie; Lin, Fang; Jan, Yih-Kuen

    2016-01-01

    Diabetic foot ulcers remain one of the most serious complications of diabetes. Peak plantar pressure (PPP) and peak pressure gradient (PPG) during walking have been shown to be associated with the development of diabetic foot ulcers. To gain further insight into the mechanical etiology of diabetic foot ulcers, examination of the pressure gradient angle (PGA) has been recently proposed. The PGA quantifies directional variation or orientation of the pressure gradient during walking and provides a measure of whether pressure gradient patterns are concentrated or dispersed along the plantar surface. We hypothesized that diabetics at risk of foot ulceration would have smaller PGA in key plantar regions, suggesting less movement of the pressure gradient over time. A total of 27 participants were studied, including 19 diabetics with peripheral neuropathy and 8 non-diabetic control subjects. A foot pressure measurement system was used to measure plantar pressures during walking. PPP, PPG, and PGA were calculated for four foot regions - first toe (T1), first metatarsal head (M1), second metatarsal head (M2), and heel (HL). Consistent with prior studies, PPP and PPG were significantly larger in the diabetic group compared with non-diabetic controls in the T1 and M1 regions, but not M2 or HL. For example, PPP was 165% (P = 0.02) and PPG was 214% (P < 0.001) larger in T1. PGA was found to be significantly smaller in the diabetic group in T1 (46%, P = 0.04), suggesting a more concentrated pressure gradient pattern under the toe. The proposed PGA may improve our understanding of the role of pressure gradient on the risk of diabetic foot ulcers.

  12. Arterial Pressure Gradients during Upright Posture and 30 deg Head Down Tilt

    NASA Technical Reports Server (NTRS)

    Sanchez, E. R; William, J. M.; Ueno, T.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

    1997-01-01

    Gravity alters local blood pressure within the body so that arterial pressures in the head and foot are lower and higher, respectively, than that at heart level. Furthermore, vascular responses to local alterations of arterial pressure are probably important to maintain orthostatic tolerance upon return to the Earth after space flight. However, it has been difficult to evaluate the body's arterial pressure gradient due to the lack of noninvasive technology. This study was therefore designed to investigate whether finger arterial pressure (FAP), measured noninvasively, follows a normal hydrostatic pressure gradient above and below heart level during upright posture and 30 deg head down tilt (HDT). Seven healthy subjects gave informed consent and were 19 to 52 years old with a height range of 158 to 181 cm. A Finapres device measured arterial pressure at different levels of the body by moving the hand from 36 cm below heart level (BH) to 72 cm above heart level (AH) in upright posture and from 36 cm BH to 48 cm AH during HDT in increments of 12 cm. Mean FAP creased by 85 mmHg transitioning from BH to AH in upright posture, and the pressure gradient calculated from hydrostatic pressure difference (rho(gh)) was 84 mmHg. In HDT, mean FAP decreased by 65 mmHg from BH to AH, and the calculated pressure gradient was also 65 mmHg. There was no significant difference between the measured FAP gradient and the calculated pressure gradient, although a significant (p = 0.023) offset was seen for absolute arterial pressure in upright posture. These results indicate that arterial pressure at various levels can be obtained from the blood pressure at heart level by calculating rho(gh) + an offset. The offset equals the difference between heart level and the site of measurement. In summary, we conclude that local blood pressure gradients can be measured by noninvasive studies of FAP.

  13. Contributions to the Data on Theoretical Metallurgy. 3. The Free Energies of Vaporization and Vapor Pressures of Inorganic Substances

    DTIC Science & Technology

    1935-01-01

    109ead-------------59 Vapor-pressure table ----------- 110 Lithium -------------------- 63 Bibliography ----------------- 115 Acceson orj NYTIS CRAMI ti...852-926*) have measured the vapor pressure of lithium in the liquid state, and Ruff and Jobannsen (32~4) have stated that the boili point is above...the results of th~e three investigations on ii u{id lithium do not agree, some arbitrar choice must be made. V this case, the data of Hartmann and

  14. 46 CFR 39.20-13 - High and low vapor pressure protection for tankships-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false High and low vapor pressure protection for tankships-T/ALL. 39.20-13 Section 39.20-13 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-13 High and low vapor pressure protection for...

  15. 46 CFR 39.20-13 - High and low vapor pressure protection for tankships-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false High and low vapor pressure protection for tankships-T/ALL. 39.20-13 Section 39.20-13 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-13 High and low vapor pressure protection for...

  16. 46 CFR 39.20-13 - High and low vapor pressure protection for tankships-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false High and low vapor pressure protection for tankships-T/ALL. 39.20-13 Section 39.20-13 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-13 High and low vapor pressure protection for...

  17. Vapor Pressures of Anesthetic Agents at Temperatures below Zero Degrees Celsius and a Novel Anesthetic Delivery Device

    PubMed Central

    Schenning, Katie J.; Casson, Henry; Click, Sarah V.; Brambrink, Lucas; Chatkupt, Thomas T.; Alkayed, Nabil J.; Hutchens, Michael P.

    2016-01-01

    At room temperature, the vapor pressures of desflurane, isoflurane, and sevoflurane are well above the clinically useful range. We hypothesized that therapeutic concentrations of these agents could be achieved at temperatures below zero, but the vapor pressure-temperature relationship is unknown below zero. Secondarily, we hypothesized that this relationship could be exploited to deliver therapeutic-range concentrations of anesthetic vapor. We therefore set out to determine the low temperature-vapor pressure relationships of each anesthetic agent thereby identifying the saturated vapor concentration of each agent at any temperature below zero. To test our hypothesis, we measured the saturated vapor concentration at 1 atmosphere of pressure for temperatures between -60°C and 0°C thus developing an empiric relationship for each agent. There was consistency in repeated experiments for all three agents. To test the empiric data we constructed a digitally-controlled thermoelectric anesthetic vaporizer, characterized the device, and used it to deliver anesthetic vapor to laboratory mice. We report, for the first time, the temperature-vapor pressure relationship at temperatures below 0°C for desflurane, isoflurane, and sevoflurane as well as the TMAC of these agents: the temperature at which the vapor pressure is equal to the minimum alveolar concentration. We describe the construction and limited validation of an anesthetic vaporizer prototype based on this principle. We conclude that clinically relevant concentrations of volatile anesthetics may be achieved at low temperatures. PMID:27632346

  18. Vapor Pressures of Anesthetic Agents at Temperatures Below 0°C and a Novel Anesthetic Delivery Device.

    PubMed

    Schenning, Katie J; Casson, Henry; Click, Sarah V; Brambrink, Lucas; Chatkupt, Thomas T; Alkayed, Nabil J; Hutchens, Michael P

    2017-02-01

    At room temperature, the vapor pressures of desflurane, isoflurane, and sevoflurane are well above the clinically useful range. We hypothesized that therapeutic concentrations of these agents could be achieved at temperatures below 0°C, but the vapor pressure-temperature relationship is unknown below 0. Second, we hypothesized that this relationship could be exploited to deliver therapeutic-range concentrations of anesthetic vapor. We therefore set out to determine the low temperature-vapor pressure relationships of each anesthetic agent, thereby identifying the saturated vapor concentration of each agent at any temperature below 0°C. To test our hypothesis, we measured the saturated vapor concentration at 1 atm of pressure for temperatures between -60 and 0°C, thus developing an empiric relationship for each agent. There was consistency in repeated experiments for all 3 agents. To test the empiric data, we constructed a digitally controlled thermoelectric anesthetic vaporizer, characterized the device, and used it to deliver anesthetic vapor to laboratory mice. We report, for the first time, the temperature-vapor pressure relationship at temperatures below 0°C for desflurane, isoflurane, and sevoflurane as well as the TMAC of these agents: the temperature at which the vapor pressure is equal to the minimum alveolar concentration. We describe the construction and limited validation of an anesthetic vaporizer prototype on the basis of this principle. We conclude that clinically relevant concentrations of volatile anesthetics may be achieved at low temperatures.

  19. 40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of my remediation material? (a) You must determine the maximum HAP vapor pressure of your remediation...

  20. Assessment of the accuracy of pharmacy students' compounded solutions using vapor pressure osmometry.

    PubMed

    Kolling, William M; McPherson, Timothy B

    2013-04-12

    OBJECTIVE. To assess the effectiveness of using a vapor pressure osmometer to measure the accuracy of pharmacy students' compounding skills. DESIGN. Students calculated the theoretical osmotic pressure (mmol/kg) of a solution as a pre-laboratory exercise, compared their calculations with actual values, and then attempted to determine the cause of any errors found. ASSESSMENT. After the introduction of the vapor pressure osmometer, the first-time pass rate for solution compounding has varied from 85% to 100%. Approximately 85% of students surveyed reported that the instrument was valuable as a teaching tool because it objectively assessed their work and provided immediate formative assessment. CONCLUSIONS. This simple technique of measuring compounding accuracy using a vapor pressure osmometer allowed students to see the importance of quality control and assessment in practice for both pharmacists and technicians.

  1. Estimation of pressure gradients at renal artery stenoses

    NASA Astrophysics Data System (ADS)

    Yim, Peter J.; Cebral, Juan R.; Weaver, Ashley; Lutz, Robert J.; Vasbinder, G. Boudewijn C.

    2003-05-01

    Atherosclerotic disease of the renal artery can reduce the blood flow leading to renovascular hypertension and ischemic nephopathy. The kidney responds to a decrease in blood flow by activation of the renin-angiotensin system that increases blood pressure and can result in severe hypertension. Percutaneous translumenal angioplasty (PTA) may be indicated for treatment of renovascular hypertension (RVH). However, direct measurement of renal artery caliber and degree of stenosis has only moderate specificity for detection of RVH. A confounding factor in assessment of the proximal renal artery is that diffuse atherosclerotic disease of the distal branches of the renal artery can produce the same effect on blood-flow as atherosclerotic disease of the proximal renal artery. A methodology is proposed for estimation of pressure gradients at renal artery stenoses from magnetic resonance imaging that could improve the evaluation of renal artery disease. In the proposed methodology, pressure gradients are estimated using computational fluid dynamics (CFD) modeling. Realistic CFD models are constructed from images of vessel shape and measurements of blood-flow rates which are available from magnetic resonance angiography (MRA) and phase-contrast magnetic resonance (MR) imaging respectively. CFD measurement of renal artery pressure gradients has been validated in a physical flow-through model.

  2. Silicates Do Nucleate in Oxygen-rich Circumstellar Outflows: New Vapor Pressure Data for SiO

    NASA Astrophysics Data System (ADS)

    Nuth, Joseph A., III; Ferguson, Frank T.

    2006-10-01

    We have measured the vapor pressure of solid SiO as a function of temperature over the range from 1325 up to 1785 K in vacuo using a modified Thermo-Cahn thermogravimetric system. Although an extrapolation of the current vapor pressure data to 2200 K is close to that predicted from the work of Schick under reducing conditions, the vapor pressures measured at successively lower temperatures diverge significantly from such predictions and are several orders of magnitude lower than predicted at 1200 K. This new vapor pressure data has been inserted into a simple model for the gas expanding from a late-stage star. Using the new vapor pressure curve makes a significant difference in the temperature and stellar radius at which SiO gas becomes supersaturated, although SiO still becomes supersaturated at temperatures that are too low to be consistent with observations. We have therefore also explored the effects of vibrational disequilibrium (as explored by Nuth & Donn) of SiO in the expanding shell on the conditions under which nucleation occurs. These calculations are much more interesting in that supersaturation now occurs at much higher kinetic temperatures. We note, however, that both vibrational disequilibrium and the new vapor pressure curve are required to induce SiO supersaturation in stellar outflows at temperatures above 1000 K.

  3. Vitrification of polymer solutions as a function of solvent quality, analyzed via vapor pressures

    NASA Astrophysics Data System (ADS)

    Bercea, Maria; Wolf, Bernhard A.

    2006-05-01

    Vapor pressures (headspace sampling in combination with gas chromatography) and glass transition temperatures [differential scanning calorimetry (DSC)] have been measured for solutions of polystyrene (PS) in either toluene (TL) (10-70°C) or cyclohexane (CH) (32-60°C) from moderately concentrated solutions up to the pure polymer. As long as the mixtures are liquid, the vapor pressure of TL (good solvent) is considerably lower than that of CH (theta solvent) under other identical conditions. These differences vanish upon the vitrification of the solutions. For TL the isothermal liquid-solid transition induced by an increase of polymer concentration takes place within a finite composition interval at constant vapor pressure; with CH this phenomenon is either absent or too insignificant to be detected. For PS solutions in TL the DSC traces look as usual, whereas these curves may become bimodal for solutions in CH. The implications of the vitrification of the polymer solutions for the determination of Flory-Huggins interaction parameters from vapor pressure data are discussed. A comparison of the results for TL/PS with recently published data on the same system demonstrates that the experimental method employed for the determination of vapor pressures plays an important role at high polymer concentrations and low temperatures.

  4. On the impact of adverse pressure gradient on the supersonic turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Wang, Qian-Cheng; Wang, Zhen-Guo; Zhao, Yu-Xin

    2016-11-01

    By employing the particle image velocimetry, the mean and turbulent characteristics of a Mach 2.95 turbulent boundary layer are experimentally investigated without the impact of curvature. The physical mechanism with which the streamwise adverse pressure gradient affects the supersonic boundary layer is revealed. The data are compared to that of the concave boundary layer with similar streamwise distributions of wall static pressure to clarify the separate impacts of the adverse pressure gradient and the concave curvature. The logarithmic law is observed to be well preserved for both of the cases. The dip below the logarithmic law is not observed in present investigation. Theoretical analysis indicates that it could be the result of compromise between the opposite impacts of the compression wave and the increased turbulent intensity. Compared to the zero pressure gradient boundary layer, the principal strain rate and the turbulent intensities are increased by the adverse pressure gradient. The shear layer formed due the hairpin packets could be sharpened by the compression wave, which leads to higher principal strain rate and the associated turbulent level. Due to the additional impact of the centrifugal instability brought by the concave wall, even higher turbulent intensities than that of the adverse pressure gradient case are introduced. The existence of velocity modes within the zero pressure gradient boundary layer suggests that the large scale motions are statistically well organized. The generation of new velocity modes due to the adverse pressure gradient indicates that the turbulent structure is changed by the adverse pressure gradient, through which more turbulence production that cannot be effectively predicted by the Reynolds-stress transport equations could be brought.

  5. Assessment of the Accuracy of Pharmacy Students’ Compounded Solutions Using Vapor Pressure Osmometry

    PubMed Central

    McPherson, Timothy B.

    2013-01-01

    Objective. To assess the effectiveness of using a vapor pressure osmometer to measure the accuracy of pharmacy students’ compounding skills. Design. Students calculated the theoretical osmotic pressure (mmol/kg) of a solution as a pre-laboratory exercise, compared their calculations with actual values, and then attempted to determine the cause of any errors found. Assessment. After the introduction of the vapor pressure osmometer, the first-time pass rate for solution compounding has varied from 85% to 100%. Approximately 85% of students surveyed reported that the instrument was valuable as a teaching tool because it objectively assessed their work and provided immediate formative assessment. Conclusions. This simple technique of measuring compounding accuracy using a vapor pressure osmometer allowed students to see the importance of quality control and assessment in practice for both pharmacists and technicians. PMID:23610476

  6. PVT properties and vapor-pressures of ordinary water substance in the critical region

    NASA Astrophysics Data System (ADS)

    Morita, T.; Sato, H.; Uematsu, M.; Watanabe, K.

    1989-03-01

    For the purpose of revealing the rather complicated thermodynamic surface of ordinary water substance in the critical region, a series of measurements of the PVT properties and the vapor-pressures of this technically important fluid have been performed by means of a constant-volume method. Ninety-three PVT measurements along 14 isotherms between 638.15 K and 652.15 K have been completed covering pressures from 18.5 to 39.2 MPa and densities from 122 to 610kg/m 3. Twenty-six vapor-pressure measurements have also been performed at temperatures between 620.15 K and 647.05 K in the near vicinity of the critical point. Our measurements are compared with other available experimental data as well as with several equations of state. We also propose a new vapor-pressure correlation from the triple point to the critical point.

  7. High-pressure liquid chromatographic gradient mixer

    DOEpatents

    Daughton, C.G.; Sakaji, R.H.

    1982-09-08

    A gradient mixer effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum band-broadening.

  8. Solar radiation and water vapor pressure to forecast chickenpox epidemics.

    PubMed

    Hervás, D; Hervás-Masip, J; Nicolau, A; Reina, J; Hervás, J A

    2015-03-01

    The clear seasonality of varicella infections in temperate regions suggests the influence of meteorologic conditions. However, there are very few data on this association. The aim of this study was to determine the seasonal pattern of varicella infections on the Mediterranean island of Mallorca (Spain), and its association with meteorologic conditions and schooling. Data on the number of cases of varicella were obtained from the Network of Epidemiologic Surveillance, which is composed of primary care physicians who notify varicella cases on a compulsory basis. From 1995 to 2012, varicella cases were correlated to temperature, humidity, rainfall, water vapor pressure, atmospheric pressure, wind speed, and solar radiation using regression and time-series models. The influence of schooling was also analyzed. A total of 68,379 cases of varicella were notified during the study period. Cases occurred all year round, with a peak incidence in June. Varicella cases increased with the decrease in water vapor pressure and/or the increase of solar radiation, 3 and 4 weeks prior to reporting, respectively. An inverse association was also observed between varicella cases and school holidays. Using these variables, the best fitting autoregressive moving average with exogenous variables (ARMAX) model could predict 95 % of varicella cases. In conclusion, varicella in our region had a clear seasonality, which was mainly determined by solar radiation and water vapor pressure.

  9. The Observed Properties of Liquid Helium at the Saturated Vapor Pressure

    NASA Astrophysics Data System (ADS)

    Donnelly, Russell J.; Barenghi, Carlo F.

    1998-11-01

    The equilibrium and transport properties of liquid 4He are deduced from experimental observations at the saturated vapor pressure. In each case, the bibliography lists all known measurements. Quantities reported here include density, thermal expansion coefficient, dielectric constant, superfluid and normal fluid densities, first, second, third, and fourth sound velocities, specific heat, enthalpy, entropy, surface tension, ion mobilities, mutual friction, viscosity and kinematic viscosity, dispersion curve, structure factor, thermal conductivity, latent heat, saturated vapor pressure, thermal diffusivity and Prandtl number of helium I, and displacement length and vortex core parameter in helium II.

  10. Luminescence from cavitation bubbles deformed in uniform pressure gradients

    NASA Astrophysics Data System (ADS)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed

    2017-09-01

    Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical bubble collapses. Luminescence was detected for bubbles of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced bubbles. The relative luminescence energy was found to rapidly decrease as a function of the bubble asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the characteristic parameters of bubble-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the bubble and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each bubble collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.

  11. Generation of region 1 current by magnetospheric pressure gradients

    NASA Technical Reports Server (NTRS)

    Yang, Y. S.; Spiro, R. W.; Wolf, R. A.

    1994-01-01

    The Rice Convection Model (RCM) is used to illustrate theoretical possibilities for generating region 1 Birkeland currents by pressure gradients on closed field lines in the Earth's magnetosphere. Inertial effects and viscous forces are neglected. The RCM is applied to idealized cases, to emphasize the basic physical ideas rather than realistic representation of the actual magnetosphere. Ionospheric conductance is taken to be uniform, and the simplest possible representations of the magnetospheric plasma are used. Three basic cases are considered: (1) the case of pure northward Interplanetary Magnetic Field (IMF), with cusp merging assumed to create new closed field lines near the nose of the magnetosphere, following the suggestion by Song and Russell (1992); (2) the case where Dungey-type reconnection occurs at the nose, but magnetosheath plasma somehow enters closed field lines on the dawnside and duskside of the merging region, causing a pressure-driven low-latitude boundary layer; and (3) the case where Dungey-type reconnection occurs at the nose, but region 1 currents flow on sunward drifting plasma sheet field lines. In case 1, currents of region 1 sense are generated by pressure gradients, but those currents do not supply the power for ionospheric convection. Results for case 2 suggest that pressure gradients at the inner edge of the low-latitude boundary layer might generate a large fraction of the region 1 Birkeland currents that drive magnetospheric convection. Results for case 3 indicate that pressure gradients in the plasma sheet could provide part of the region 1 current.

  12. Transient-pressure analysis in geothermal steam reservoirs with an immobile vaporizing liquid phase

    USGS Publications Warehouse

    Moench, A.F.; Atkinson, P.G.

    1978-01-01

    A finite-difference model for the radial horizontal flow of steam through a porous medium is used to evaluate transient-pressure behavior in the presence of an immobile vaporizing or condensing liquid phase. Graphs of pressure drawdown and buildup in terms of dimensionless pressure and time are obtained for a well discharging steam at a constant mass flow rate for a specified time. The assumptions are made that the steam is in local thermal equilibrium with the reservoir rocks, that temperature changes are due only to phase change, and that effects of vapor-pressure lowering are negligible. Computations show that when a vaporizing liquid phase is present the pressure drawdown exhibits behavior similar to that observed in noncondensable gas reservoirs, but delayed in time. A theoretical analysis allows for the computation of this delay and demonstrates that it is independent of flow geometry. The response that occurs upon pressure buildup is markedly different from that in a noncondensable gas system. This result may provide a diagnostic tool for establishing the existence of phase-change phenomena within a reservoir. ?? 1979.

  13. Analytic Formulation and Numerical Implementation of an Acoustic Pressure Gradient Prediction

    NASA Technical Reports Server (NTRS)

    Lee, Seongkyu; Brentner, Kenneth S.; Farassat, Fereidoun

    2007-01-01

    The scattering of rotor noise is an area that has received little attention over the years, yet the limited work that has been done has shown that both the directivity and intensity of the acoustic field may be significantly modified by the presence of scattering bodies. One of the inputs needed to compute the scattered acoustic field is the acoustic pressure gradient on a scattering surface. Two new analytical formulations of the acoustic pressure gradient have been developed and implemented in the PSU-WOPWOP rotor noise prediction code. These formulations are presented in this paper. The first formulation is derived by taking the gradient of Farassat's retarded-time Formulation 1A. Although this formulation is relatively simple, it requires numerical time differentiation of the acoustic integrals. In the second formulation, the time differentiation is taken inside the integrals analytically. The acoustic pressure gradient predicted by these new formulations is validated through comparison with the acoustic pressure gradient determined by a purely numerical approach for two model rotors. The agreement between analytic formulations and numerical method is excellent for both stationary and moving observers case.

  14. The optimum intermediate pressure of two-stages vapor compression refrigeration cycle for Air-Conditioning unit

    NASA Astrophysics Data System (ADS)

    Ambarita, H.; Sihombing, H. V.

    2018-03-01

    Vapor compression cycle is mainly employed as a refrigeration cycle in the Air-Conditioning (AC) unit. In order to save energy, the Coefficient of Performance (COP) of the need to be improved. One of the potential solutions is to modify the system into multi-stages vapor compression cycle. The suitable intermediate pressure between the high and low pressures is one of the design issues. The present work deals with the investigation of an optimum intermediate pressure of two-stages vapor compression refrigeration cycle. Typical vapor compression cycle that is used in AC unit is taken into consideration. The used refrigerants are R134a. The governing equations have been developed for the systems. An inhouse program has been developed to solve the problem. COP, mass flow rate of the refrigerant and compressor power as a function of intermediate pressure are plotted. It was shown that there exists an optimum intermediate pressure for maximum COP. For refrigerant R134a, the proposed correlations need to be revised.

  15. Notes on Vapor Pressure Equilibria Measurements

    NASA Astrophysics Data System (ADS)

    Krieger, Albert G.; Henderson, John W.

    1996-11-01

    After reading the article in this Journal (1), we would like to share our experience with a similar experiment based on an earlier article in this Journal (2). Freshman students at our institution use manometers and 24/40 ground-glass distillation apparatus (abandoned by our organic chemistry classes) to measure boiling points at reduced pressures. Distilled water and 2-methyl-1-propanol are typical liquids of interest. Students enter their collected data into an Excel template which generates graphs of P vs. T and log P vs 1/T to demonstrate the nonlinear and linear relationships that exist between vapor pressures and temperatures. The templates use the Clausius-Clapeyron equation to determine the normal boiling point and the enthalpy of vaporization of the liquid studies. The boiling point determined for water is 100 oC and for 2-methyl-1-propanol is 106 oC, within 2 o of the CRC Handbook data. We have found that the availability of state-of-the-art equipment need not limit the ability to teach and demonstrate fundamental principles. The Excel template (Macintosh) is available upon request domestically and for the cost of international postage for others. Literature Cited 1. Kidahl, N.; Berka, L. H. J. Chem. Educ. 1995, 72, 258. 2. Schaber, P. M. J. Chem. Educ. 1985, 62, 345.

  16. High pressure liquid chromatographic gradient mixer

    DOEpatents

    Daughton, Christian G.; Sakaji, Richard H.

    1985-01-01

    A gradient mixer which effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum "band-broadening".

  17. Direct measurements of local bed shear stress in the presence of pressure gradients

    NASA Astrophysics Data System (ADS)

    Pujara, Nimish; Liu, Philip L.-F.

    2014-07-01

    This paper describes the development of a shear plate sensor capable of directly measuring the local mean bed shear stress in small-scale and large-scale laboratory flumes. The sensor is capable of measuring bed shear stress in the range 200 Pa with an accuracy up to 1 %. Its size, 43 mm in the flow direction, is designed to be small enough to give spatially local measurements, and its bandwidth, 75 Hz, is high enough to resolve time-varying forcing. Typically, shear plate sensors are restricted to use in zero pressure gradient flows because secondary forces on the edge of the shear plate caused by pressure gradients can introduce large errors. However, by analysis of the pressure distribution at the edges of the shear plate in mild pressure gradients, we introduce a new methodology for correcting for the pressure gradient force. The developed sensor includes pressure tappings to measure the pressure gradient in the flow, and the methodology for correction is applied to obtain accurate measurements of bed shear stress under solitary waves in a small-scale wave flume. The sensor is also validated by measurements in a turbulent flat plate boundary layer in open channel flow.

  18. Distillation device supplies cesium vapor at constant pressure

    NASA Technical Reports Server (NTRS)

    Basiulis, A.; Shefsiek, P. K.

    1968-01-01

    Distillation apparatus in the form of a U tube supplies small amounts of pure cesium vapor at constant pressure to a thermionic converter. The upstream leg of the U tube is connected to a vacuum pump to withdraw noncondensable impurities, the bottom portion serves as a reservoir for the liquid cesium.

  19. The role of thermal vapor diffusion in the subsurface hydrologic evolution of Mars

    NASA Technical Reports Server (NTRS)

    Clifford, Stephen M.

    1991-01-01

    The hydrologic response of groundwater to the thermal evolution of the early martian crust is considered. When a temperature gradient is present in a moist porous medium, it gives rise to a vapor-pressure gradient that drives the diffusion of water vapor from regions of high to low temperature. By this process, a geothermal gradient as small as 15 K/km could drive the vertical transport of 1 km of water to the freezing front at the base of the martian crysophere every 10 exp 6-10 exp 7 years, or the equivalent of about 100-1000 km of water over the course of martian geologic history. Models of the thermal history of Mars suggest that this thermally-driven vapor flux may have been as much as 3-5 times greater in the past. The magnitude of this transport suggests that the process of geothermally-induced vapor diffusion may have played a critical role in the initial emplacement of ground ice and the subsequent geomorphic and geochemical evolution of the martian crust.

  20. Quantitative structure-property relationships for prediction of boiling point, vapor pressure, and melting point.

    PubMed

    Dearden, John C

    2003-08-01

    Boiling point, vapor pressure, and melting point are important physicochemical properties in the modeling of the distribution and fate of chemicals in the environment. However, such data often are not available, and therefore must be estimated. Over the years, many attempts have been made to calculate boiling points, vapor pressures, and melting points by using quantitative structure-property relationships, and this review examines and discusses the work published in this area, and concentrates particularly on recent studies. A number of software programs are commercially available for the calculation of boiling point, vapor pressure, and melting point, and these have been tested for their predictive ability with a test set of 100 organic chemicals.

  1. New class of compounds have very low vapor pressures

    NASA Technical Reports Server (NTRS)

    Angell, C. A.; Gruen, D. M.

    1967-01-01

    Magnesium hexahydrate tetrachlorometallates are 50-volume-percent water, have a high melting point and possess a low vapor pressure. These new compounds are relatively noncorrosive, thermally stable, and water soluble but not hygroscopic. They may have potential applications as cooling fluids.

  2. A wet/wet differential pressure sensor for measuring vertical hydraulic gradient.

    PubMed

    Fritz, Brad G; Mackley, Rob D

    2010-01-01

    Vertical hydraulic gradient is commonly measured in rivers, lakes, and streams for studies of groundwater-surface water interaction. While a number of methods with subtle differences have been applied, these methods can generally be separated into two categories; measuring surface water elevation and pressure in the subsurface separately or making direct measurements of the head difference with a manometer. Making separate head measurements allows for the use of electronic pressure sensors, providing large datasets that are particularly useful when the vertical hydraulic gradient fluctuates over time. On the other hand, using a manometer-based method provides an easier and more rapid measurement with a simpler computation to calculate the vertical hydraulic gradient. In this study, we evaluated a wet/wet differential pressure sensor for use in measuring vertical hydraulic gradient. This approach combines the advantage of high-temporal frequency measurements obtained with instrumented piezometers with the simplicity and reduced potential for human-induced error obtained with a manometer board method. Our results showed that the wet/wet differential pressure sensor provided results comparable to more traditional methods, making it an acceptable method for future use.

  3. New Micro-Method for Prediction of Vapor Pressure of Energetic Materials

    DTIC Science & Technology

    2014-07-01

    temperature is recorded as the extrapolated onset temperature (11–12). • Gas chromatography (GC) headspace analysis requires the establishment of an...J. L.; Shinde, K.; Moran, J. Determination of the Vapor Density of Triacetone Triperoxide (TATP) Using a Gas Chromatography Headspace Technique...Propellants Explos. Pyrotech. 2005, 30 (2), 127–30. 14. Chickos, J. S. Sublimation Vapor Pressures as Evaluated by Correlation- Gas Chromatography . J

  4. Experimental analysis of the boundary layer transition with zero and positive pressure gradient

    NASA Technical Reports Server (NTRS)

    Arnal, D.; Jullen, J. C.; Michel, R.

    1980-01-01

    The influence of a positive pressure gradient on the boundary layer transition is studied. The mean velocity and turbulence profiles of four cases are examined. As the intensity of the pressure gradient is increased, the Reynolds number of the transition onset and the length of the transition region are reduced. The Tollmein-Schlichting waves disturb the laminar regime; the amplification of these waves is in good agreement with the stability theory. The three dimensional deformation of the waves leads finally to the appearance of turbulence. In the case of zero pressure gradient, the properties of the turbulent spots are studied by conditional sampling of the hot-wire signal; in the case of positive pressure gradient, the turbulence appears in a progressive manner and the turbulent spots are much more difficult to characterize.

  5. Secondary subharmonic instability of boundary layers with pressure gradient and suction

    NASA Technical Reports Server (NTRS)

    El-Hady, Nabil M.

    1988-01-01

    Three-dimensional linear secondary instability is investigated for boundary layers with pressure gradient and suction in the presence of a finite amplitude TS wave. The focus is on principal parametric resonance responsible for a strong growth of subharmonics in a low disturbance environment. Calculations are presented for the effect of pressure gradients and suction on controlling the onset and amplification of the secondary instability.

  6. Unusual effect of water vapor pressure on dehydration of dibasic calcium phosphate dihydrate.

    PubMed

    Kaushal, Aditya M; Vangala, Venu R; Suryanarayanan, Raj

    2011-04-01

    Dibasic calcium phosphate occurs as an anhydrate (DCPA; CaHPO₄) and as a dihydrate (DCPD; CaHPO₄•2H₂O). Our objective was to investigate the unusual behavior of these phases. Dibasic calcium phosphate dihydrate was dehydrated in a (i) differential scanning calorimeter (DSC) in different pan configurations; (ii) variable-temperature X-ray diffractometer (XRD) at atmospheric and under reduced pressure, and in sealed capillaries; and (iii) water vapor sorption analyzer at varying temperature and humidity conditions. Dehydration was complete by 210°C in an open DSC pan and under atmospheric pressure in the XRD. Unlike "conventional" hydrates, the dehydration of DCPD was facilitated in the presence of water vapor. Variable-temperature XRD in a sealed capillary and DSC in a hermetic pan with pinhole caused complete dehydration by 100°C and 140°C, respectively. Under reduced pressure, conversion to the anhydrate was incomplete even at 300°C. The increase in dehydration rate with increase in water vapor pressure has been explained by the Smith-Topley effect. Under "dry" conditions, a coating of poorly crystalline product is believed to form on the surface of particles and act as a barrier to further dehydration. However, in the presence of water vapor, recrystallization occurs, creating cracks and channels and facilitating continued dehydration. Copyright © 2010 Wiley-Liss, Inc.

  7. Experimental feasibility of investigating acoustic waves in Couette flow with entropy and pressure gradients

    NASA Technical Reports Server (NTRS)

    Parrott, Tony L.; Zorumski, William E.; Rawls, John W., Jr.

    1990-01-01

    The feasibility is discussed for an experimental program for studying the behavior of acoustic wave propagation in the presence of strong gradients of pressure, temperature, and flow. Theory suggests that gradients effects can be experimentally observed as resonant frequency shifts and mode shape changes in a waveguide. A convenient experimental geometry for such experiments is the annular region between two co-rotating cylinders. Radial temperature gradients in a spinning annulus can be generated by differentially heating the two cylinders via electromagnetic induction. Radial pressure gradients can be controlled by varying the cylinder spin rates. Present technology appears adequate to construct an apparatus to allow independent control of temperature and pressure gradients. A complicating feature of a more advanced experiment, involving flow gradients, is the requirement for independently controlled cylinder spin rates. Also, the boundary condition at annulus terminations must be such that flow gradients are minimally disturbed. The design and construction of an advanced apparatus to include flow gradients will require additional technology development.

  8. Pressure control in interfacial systems: Atomistic simulations of vapor nucleation

    NASA Astrophysics Data System (ADS)

    Marchio, S.; Meloni, S.; Giacomello, A.; Valeriani, C.; Casciola, C. M.

    2018-02-01

    A large number of phenomena of scientific and technological interest involve multiple phases and occur at constant pressure of one of the two phases, e.g., the liquid phase in vapor nucleation. It is therefore of great interest to be able to reproduce such conditions in atomistic simulations. Here we study how popular barostats, originally devised for homogeneous systems, behave when applied straightforwardly to heterogeneous systems. We focus on vapor nucleation from a super-heated Lennard-Jones liquid, studied via hybrid restrained Monte Carlo simulations. The results show a departure from the trends predicted for the case of constant liquid pressure, i.e., from the conditions of classical nucleation theory. Artifacts deriving from standard (global) barostats are shown to depend on the size of the simulation box. In particular, for Lennard-Jones liquid systems of 7000 and 13 500 atoms, at conditions typically found in the literature, we have estimated an error of 10-15 kBT on the free-energy barrier, corresponding to an error of 104-106 s-1σ-3 on the nucleation rate. A mechanical (local) barostat is proposed which heals the artifacts for the considered case of vapor nucleation.

  9. Analytic Formulation and Numerical Implementation of an Acoustic Pressure Gradient Prediction

    NASA Technical Reports Server (NTRS)

    Lee, Seongkyu; Brentner, Kenneth S.; Farassat, F.; Morris, Philip J.

    2008-01-01

    Two new analytical formulations of the acoustic pressure gradient have been developed and implemented in the PSU-WOPWOP rotor noise prediction code. The pressure gradient can be used to solve the boundary condition for scattering problems and it is a key aspect to solve acoustic scattering problems. The first formulation is derived from the gradient of the Ffowcs Williams-Hawkings (FW-H) equation. This formulation has a form involving the observer time differentiation outside the integrals. In the second formulation, the time differentiation is taken inside the integrals analytically. This formulation avoids the numerical time differentiation with respect to the observer time, which is computationally more efficient. The acoustic pressure gradient predicted by these new formulations is validated through comparison with available exact solutions for a stationary and moving monopole sources. The agreement between the predictions and exact solutions is excellent. The formulations are applied to the rotor noise problems for two model rotors. A purely numerical approach is compared with the analytical formulations. The agreement between the analytical formulations and the numerical method is excellent for both stationary and moving observer cases.

  10. Computation of Turbulent Wake Flows in Variable Pressure Gradient

    NASA Technical Reports Server (NTRS)

    Duquesne, N.; Carlson, J. R.; Rumsey, C. L.; Gatski, T. B.

    1999-01-01

    Transport aircraft performance is strongly influenced by the effectiveness of high-lift systems. Developing wakes generated by the airfoil elements are subjected to strong pressure gradients and can thicken very rapidly, limiting maximum lift. This paper focuses on the effects of various pressure gradients on developing symmetric wakes and on the ability of a linear eddy viscosity model and a non-linear explicit algebraic stress model to accurately predict their downstream evolution. In order to reduce the uncertainties arising from numerical issues when assessing the performance of turbulence models, three different numerical codes with the same turbulence models are used. Results are compared to available experimental data to assess the accuracy of the computational results.

  11. Apparatus to measure the vapor pressure of slowly decomposing compounds from 1 Pa to 105 Pa

    PubMed Central

    Berg, Robert F.

    2016-01-01

    This article describes an apparatus and method for measuring vapor pressures in the range from 1 Pa to 105 Pa. Its three distinctive elements are : (1) the static pressure measurements were made with only a small temperature difference between the vapor and the condensed phase, (2) the sample was degassed in situ, and (3) the temperature range extended up to 200 °C. The apparatus was designed to measure metal-organic precursors, which often are toxic, pyrophoric, or unstable. Vapor pressures are presented for naphthalene, ferrocene, diethyl phthalate, and TEMAH (tetrakisethylmethylaminohafnium). Also presented are data for the temperature-dependent decomposition rate of TEMAH. PMID:27274567

  12. Advanced Computational Modeling of Vapor Deposition in a High-Pressure Reactor

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  13. Advanced Computational Modeling of Vapor Deposition in a High-pressure Reactor

    NASA Technical Reports Server (NTRS)

    Cardelino, Beatriz H.; Moore, Craig E.; McCall, Sonya D.; Cardelino, Carlos A.; Dietz, Nikolaus; Bachmann, Klaus

    2004-01-01

    In search of novel approaches to produce new materials for electro-optic technologies, advances have been achieved in the development of computer models for vapor deposition reactors in space. Numerical simulations are invaluable tools for costly and difficult processes, such as those experiments designed for high pressures and microgravity conditions. Indium nitride is a candidate compound for high-speed laser and photo diodes for optical communication system, as well as for semiconductor lasers operating into the blue and ultraviolet regions. But InN and other nitride compounds exhibit large thermal decomposition at its optimum growth temperature. In addition, epitaxy at lower temperatures and subatmospheric pressures incorporates indium droplets into the InN films. However, surface stabilization data indicate that InN could be grown at 900 K in high nitrogen pressures, and microgravity could provide laminar flow conditions. Numerical models for chemical vapor deposition have been developed, coupling complex chemical kinetics with fluid dynamic properties.

  14. Thermophoresis of dissolved molecules and polymers: Consideration of the temperature-induced macroscopic pressure gradient

    NASA Astrophysics Data System (ADS)

    Semenov, Semen; Schimpf, Martin

    2004-01-01

    The movement of molecules and homopolymer chains dissolved in a nonelectrolyte solvent in response to a temperature gradient is considered a consequence of temperature-induced pressure gradients in the solvent layer surrounding the solute molecules. Local pressure gradients are produced by nonuniform London van der Waals interactions, established by gradients in the concentration (density) of solvent molecules. The density gradient is produced by variations in solvent thermal expansion within the nonuniform temperature field. The resulting expression for the velocity of the solute contains the Hamaker constants for solute-solvent and solute-solute interactions, the radius of the solute molecule, and the viscosity and cubic coefficient of thermal expansion of the solvent. In this paper we consider an additional force that arises from directional asymmetry in the interaction between solvent molecules. In a closed cell, the resulting macroscopic pressure gradient gives rise to a volume force that affects the motion of dissolved solutes. An expression for this macroscopic pressure gradient is derived and the resulting force is incorporated into the expression for the solute velocity. The expression is used to calculate thermodiffusion coefficients for polystyrene in several organic solvents. When these values are compared to those measured in the laboratory, the consistency is better than that found in previous reports, which did not consider the macroscopic pressure gradient that arises in a closed thermodiffusion cell. The model also allows for the movement of solute in either direction, depending on the relative values of the solvent and solute Hamaker constants.

  15. Thermal-hydraulic behaviors of vapor-liquid interface due to arrival of a pressure wave

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Inoue, Akira; Fujii, Yoshifumi; Matsuzaki, Mitsuo

    In the vapor explosion, a pressure wave (shock wave) plays a fundamental role for triggering, propagation and enhancement of the explosion. Energy of the explosion is related to the magnitude of heat transfer rate from hot liquid to cold volatile one. This is related to an increasing rate of interface area and to an amount of transient heat flux between the liquids. In this study, the characteristics of transient heat transfer and behaviors of vapor film both on the platinum tube and on the hot melt tin drop, under same boundary conditions have been investigated. It is considered that theremore » exists a fundamental mechanism of the explosion in the initial expansion process of the hot liquid drop immediately after arrival of pressure wave. The growth rate of the vapor film is much faster on the hot liquid than that on the solid surface. Two kinds of roughness were observed, one due to the Taylor instability, by rapid growth of the explosion bubble, and another, nucleation sites were observed at the vapor-liquid interface. Based on detailed observation of early stage interface behaviors after arrival of a pressure wave, the thermal fragmentation mechanism is proposed.« less

  16. 40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

  17. 40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

  18. 40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

  19. 40 CFR 63.7944 - How do I determine the maximum HAP vapor pressure of my remediation material?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... vapor pressure of my remediation material? 63.7944 Section 63.7944 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Performance Tests § 63.7944 How do I determine the maximum HAP vapor pressure of...

  20. Observations of wave-induced pore pressure gradients and bed level response on a surf zone sandbar

    NASA Astrophysics Data System (ADS)

    Anderson, Dylan; Cox, Dan; Mieras, Ryan; Puleo, Jack A.; Hsu, Tian-Jian

    2017-06-01

    Horizontal and vertical pressure gradients may be important physical mechanisms contributing to onshore sediment transport beneath steep, near-breaking waves in the surf zone. A barred beach was constructed in a large-scale laboratory wave flume with a fixed profile containing a mobile sediment layer on the crest of the sandbar. Horizontal and vertical pore pressure gradients were obtained by finite differences of measurements from an array of pressure transducers buried within the upper several centimeters of the bed. Colocated observations of erosion depth were made during asymmetric wave trials with wave heights between 0.10 and 0.98 m, consistently resulting in onshore sheet flow sediment transport. The pore pressure gradient vector within the bed exhibited temporal rotations during each wave cycle, directed predominantly upward under the trough and then rapidly rotating onshore and downward as the wavefront passed. The magnitude of the pore pressure gradient during each phase of rotation was correlated with local wave steepness and relative depth. Momentary bed failures as deep as 20 grain diameters were coincident with sharp increases in the onshore-directed pore pressure gradients, but occurred at horizontal pressure gradients less than theoretical critical values for initiation of the motion for compact beds. An expression combining the effects of both horizontal and vertical pore pressure gradients with bed shear stress and soil stability is used to determine that failure of the bed is initiated at nonnegligible values of both forces.Plain Language SummaryThe <span class="hlt">pressure</span> <span class="hlt">gradient</span> present within the seabed beneath breaking waves may be an important physical mechanism transporting sediment. A large-scale laboratory was used to replicate realistic surfzone conditions in controlled tests, allowing for horizontal and vertical <span class="hlt">pressure</span> <span class="hlt">gradient</span> magnitudes and the resulting sediment bed response to be observed with</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8160828','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8160828"><span>Intramyocardial <span class="hlt">pressure</span> <span class="hlt">gradients</span> in working and nonworking isolated cat hearts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mihailescu, L S; Abel, F L</p> <p>1994-03-01</p> <p>This study presents an improved method for the measurement of intramyocardial <span class="hlt">pressure</span> (IMP) using the servo-nulling mechanism. Glass micropipettes (20-24 microns OD) were used as transducers, coated to increase their mechanical resistance to breakage, and placed inside the left ventricular wall with a micropipette holder and manipulator. IMP was measured at the base of the left ventricle in working and nonworking isolated cat hearts that were perfused with Krebs-Henseleit buffer. In working hearts a transmural <span class="hlt">gradient</span> of systolic IMP oriented from endocardium toward the epicardium was found; the endocardial values for systolic IMP were slightly higher than systolic left ventricular <span class="hlt">pressure</span> (LVP), by 11-18%. Increases in afterload induced increases in IMP, without changing the systolic IMP-to-LVP ratio. In nonworking hearts with drained left ventricles, the systolic transmural <span class="hlt">gradient</span> for IMP described for working hearts persisted, but at lower values, and was directly dependent on coronary perfusion <span class="hlt">pressure</span>. Systolic IMP-to-LVP ratios were always > 1. The diastolic IMP of both working and nonworking hearts exhibited irregular transmural <span class="hlt">gradients</span>. Our results support the view that generated systolic IMP is largely independent of LVP development.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18264220','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18264220"><span>Fabrication and characterization of a planar <span class="hlt">gradient</span>-index, plasma-enhanced chemical <span class="hlt">vapor</span> deposition lens.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Beltrami, D R; Love, J D; Durandet, A; Samo, A; Cogswell, C J</p> <p>1997-10-01</p> <p>A thin, one-dimensional, <span class="hlt">gradient</span>-index slab lens with a parabolic profile was designed and fabricated in fluorine-doped silica by use of plasma-enhanced chemical <span class="hlt">vapor</span> deposition in a Helicon plasma reactor. The refractive-index profile of the fabricated lens was determined by the application of an inversion technique to the values of modal effective index measured with a prism coupler. The periodic refocusing property of the lens and the independence of the wavelength were measured with the fluorescence of a specially doped, thin polymer layer spin-coated onto the surface of the lens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..DFDL22008C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..DFDL22008C"><span>Assessment of fluctuating <span class="hlt">pressure</span> <span class="hlt">gradient</span> using acceleration spectra in near wall flows</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cadel, Daniel; Lowe, K. Todd</p> <p>2015-11-01</p> <p>Separation of contributions to the fluctuating acceleration from <span class="hlt">pressure</span> <span class="hlt">gradient</span> fluctuations and viscous shear fluctuations in the frequency domain is examined in a turbulent boundary layer. Past work leveraging turbulent accelerations for <span class="hlt">pressure</span> <span class="hlt">gradient</span> measurements has neglected the viscous shear term from the momentum equation--an invalid assumption in the case of near wall flows. The present study seeks to account for the influence of the viscous shear term and spectrally reject its contribution, which is thought to be concentrated at higher frequencies. Spectra of velocity and acceleration fluctuations in a flat plate, zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> turbulent boundary layer at a momentum thickness Reynolds number of 7500 are measured using a spatially resolving three-component laser Doppler velocimeter. This canonical case data is applied for validation of the spectral approach for future application in more complex aerodynamic flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..DFDA25002K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..DFDA25002K"><span>Plasma Streamwise Vortex Generators in an Adverse <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelley, Christopher; Corke, Thomas; Thomas, Flint</p> <p>2013-11-01</p> <p>A wind tunnel experiment was conducted to compare plasma streamwise vortex generators (PSVGs) and passive vortex generators (VGs). These devices were installed on a wing section by which the angle of attack could be used to vary the streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The experiment was performed for freestream Mach numbers 0.1-0.2. Three-dimensional velocity components were measured using a 5-hole Pitot probe in the boundary layer. These measurements were used to quantify the production of streamwise vorticity and the magnitude of the reorientation term from the vorticity transport equation. The effect of Mach number, <span class="hlt">pressure</span> <span class="hlt">gradient</span>, operating voltage, and electrode length was then investigated for the PSVGs. The results indicate that the PSVGs could easily outperform the passive VGs and provide a suitable alternative for flow control.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA587772','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA587772"><span><span class="hlt">Vapor</span> <span class="hlt">Pressure</span> of Bis-(2-chloroethyl)ethylamine (HN1)</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2013-10-01</p> <p>coefficient of the compound. 4 Analysis of an aliquot of the material by 13 C nuclear magnetic resonance (NMR) spectroscopy, gas chromatography ...ACRONYMS AND ABBREVIATIONS CW chemical warfare ECBC U.S. Army Edgewood Chemical Biological Center GC gas chromatography HN1 bis-(2...compounds for determining <span class="hlt">vapor</span> <span class="hlt">pressures</span>. The arrows indicate the direction of flow of the nitrogen carrier gas</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24861781','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24861781"><span>Constant <span class="hlt">pressure</span> mode extended simple <span class="hlt">gradient</span> liquid chromatography system for micro and nanocolumns.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Šesták, Jozef; Kahle, Vladislav</p> <p>2014-07-11</p> <p>Performing <span class="hlt">gradient</span> liquid chromatography at constant <span class="hlt">pressure</span> instead of constant flow rate has serious potential for shortening the analysis time and increasing the productivity of HPLC instruments that use <span class="hlt">gradient</span> methods. However, in the constant <span class="hlt">pressure</span> mode the decreasing column permeability during a long period of time negatively affects the repeatability of retention time. Thus a volume-based approach, in which the detector signal is plotted as a function of retention volume, must be taken into consideration. Traditional HPLC equipment, however, requires quite complex hardware and software modifications in order to work at constant <span class="hlt">pressure</span> and in the volume-based mode. In this short communication, a low cost and easily feasible <span class="hlt">pressure</span>-controlled extension of the previously described simple <span class="hlt">gradient</span> liquid chromatography platform is proposed. A test mixture of four nitro esters was separated by 10-60% (v/v) acetone/water <span class="hlt">gradient</span> and a high repeatability of retention volumes at 20MPa (RSD less than 0.45%) was realized. Separations were also performed at different values of <span class="hlt">pressure</span> (20, 25, and 31MPa), and only small variations of the retention volumes (up to 0.8%) were observed. In this particular case, the gain in the analysis speed of 7% compared to the constant flow mode was realized at a constant <span class="hlt">pressure</span>. Copyright © 2014 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8796E..1OG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8796E..1OG"><span>Influence of the helium-<span class="hlt">pressure</span> on diode-pumped alkali-<span class="hlt">vapor</span> laser</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Fei; Chen, Fei; Xie, Ji-jiang; Zhang, Lai-ming; Li, Dian-jun; Yang, Gui-long; Guo, Jing</p> <p>2013-05-01</p> <p>Diode-pumped alkali-<span class="hlt">vapor</span> laser (DPAL) is a kind of laser attracted much attention for its merits, such as high quantum efficiency, excellent beam quality, favorable thermal management, and potential scalability to high power and so on. Based on the rate-equation theory of end-pumped DPAL, the performances of DPAL using Cs-<span class="hlt">vapor</span> collisionally broadened by helium are simulated and studied. With the increase of helium <span class="hlt">pressure</span>, the numerical results show that: 1) the absorption line-width increases and the stimulated absorption cross-section decreases contrarily; 2) the threshold pumping power decreases to minimum and then rolls over to increase linearly; 3) the absorption efficiency rises to maximum initially due to enough large stimulated absorption cross-section in the far wings of collisionally broadened D2 transition (absorption transition), and then begins to reduce; 4) an optimal value of helium <span class="hlt">pressure</span> exists to obtain the highest output power, leading to an optimal optical-optical efficiency. Furthermore, to generate the self-oscillation of laser, a critical value of helium <span class="hlt">pressure</span> occurs when small-signal gain equals to the threshold gain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000AIPC..532..107V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000AIPC..532..107V"><span>Contribution of water <span class="hlt">vapor</span> <span class="hlt">pressure</span> to <span class="hlt">pressurization</span> of plutonium dioxide storage containers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veirs, D. Kirk; Morris, John S.; Spearing, Dane R.</p> <p>2000-07-01</p> <p><span class="hlt">Pressurization</span> of long-term storage containers filled with materials meeting the US DOE storage standard is of concern.1,2 For example, temperatures within storage containers packaged according to the standard and contained in 9975 shipping packages that are stored in full view of the sun can reach internal temperatures of 250 °C.3 Twenty five grams of water (0.5 wt.%) at 250 °C in the storage container with no other material present would result in a <span class="hlt">pressure</span> of 412 psia, which is limited by the amount of water. The <span class="hlt">pressure</span> due to the water can be substantially reduced due to interactions with the stored material. Studies of the adsorption of water by PuO2 and surface interactions of water with PuO2 show that adsorption of 0.5 wt.% of water is feasible under many conditions and probable under high humidity conditions.4,5,6 However, no data are available on the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of water over plutonium dioxide containing materials that have been exposed to water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhRvM...2d0401N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhRvM...2d0401N"><span>In situ ESEM imaging of the <span class="hlt">vapor-pressure</span>-dependent sublimation-induced morphology of ice</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nair, Malavika; Husmann, Anke; Cameron, Ruth E.; Best, Serena M.</p> <p>2018-04-01</p> <p>Sublimation is a fundamental phase transition that has a profound impact on both natural phenomena and advanced manufacturing technologies. Although great strides have been made in the study of ice growth from melt and <span class="hlt">vapor</span>, little consideration has been given to the effect of sublimation on the morphological features that develop in the ice microstructure. In this experimental study, we demonstrate the effect of <span class="hlt">vapor</span> <span class="hlt">pressure</span> on the mesoscopic faceting observed and show that a <span class="hlt">vapor-pressure</span>-specific wavelength characterizes the periodic features that arise during sublimation. The ability to control the length scale of these features not only provides us with new insights into the mesoscopic roughness of ice crystals, but also presents the potential to exploit this effect in a plethora of applications from comet dating to ice-templated tissue engineering scaffolds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28296135','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28296135"><span>Assessment of trans-aortic <span class="hlt">pressure</span> <span class="hlt">gradient</span> using a coronary <span class="hlt">pressure</span> wire in patients with mechanical aortic and mitral valve prostheses.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kherada, Nisharahmed; Brenes, Juan Carlos; Kini, Annapoorna S; Dangas, George D</p> <p>2017-03-15</p> <p>Accurate evaluation of trans-aortic valvular <span class="hlt">pressure</span> <span class="hlt">gradients</span> is challenging in cases where dual mechanical aortic and mitral valve prostheses are present. Non-invasive Doppler echocardiographic imaging has its limitations due to multiple geometric assumptions. Invasive measurement of trans-valvular <span class="hlt">gradients</span> with cardiac catheterization can provide further information in patients with two mechanical valves, where simultaneous <span class="hlt">pressure</span> measurements in the left ventricle and ascending aorta must be obtained. Obtaining access to the left ventricle via the mitral valve after a trans-septal puncture is not feasible in the case of a concomitant mechanical mitral valve, whereas left ventricular apical puncture technique is associated with high procedural risks. Retrograde crossing of a bileaflet mechanical aortic prosthesis with standard catheters is associated with the risk of catheter entrapment and acute valvular regurgitation. In these cases, the assessment of trans-valvular <span class="hlt">gradients</span> using a 0.014˝ diameter coronary <span class="hlt">pressure</span> wire technique has been described in a few case reports. We present the case of a 76-year-old female with rheumatic valvular heart disease who underwent mechanical aortic and mitral valve replacement in the past. She presented with decompensated heart failure and echocardiographic findings suggestive of elevated <span class="hlt">pressure</span> <span class="hlt">gradient</span> across the mechanical aortic valve prosthesis. The use of a high-fidelity 0.014˝ diameter coronary <span class="hlt">pressure</span> guidewire resulted in the detection of a normal trans-valvular <span class="hlt">pressure</span> <span class="hlt">gradient</span> across the mechanical aortic valve. This avoided a high-risk third redo valve surgery in our patient. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030000596','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030000596"><span>Atmospheric <span class="hlt">Pressure</span> Spray Chemical <span class="hlt">Vapor</span> Deposited CuInS2 Thin Films for Photovoltaic Applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Harris, J. D.; Raffaelle, R. P.; Banger, K. K.; Smith, M. A.; Scheiman, D. A.; Hepp, A. F.</p> <p>2002-01-01</p> <p>Solar cells have been prepared using atmospheric <span class="hlt">pressure</span> spray chemical <span class="hlt">vapor</span> deposited CuInS2 absorbers. The CuInS2 films were deposited at 390 C using the single source precursor (PPh3)2CuIn(SEt)4 in an argon atmosphere. The absorber ranges in thickness from 0.75 - 1.0 micrometers, and exhibits a crystallographic <span class="hlt">gradient</span>, with the leading edge having a (220) preferred orientation and the trailing edge having a (112) orientation. Schottky diodes prepared by thermal evaporation of aluminum contacts on to the CuInS2 yielded diodes for films that were annealed at 600 C. Solar cells were prepared using annealed films and had the (top down) composition of Al/ZnO/CdS/CuInS2/Mo/Glass. The Jsc, Voc, FF and (eta) were 6.46 mA per square centimeter, 307 mV, 24% and 0.35%, respectively for the best small area cells under simulated AM0 illumination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26ES..103a2011A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26ES..103a2011A"><span>Probabilistic approach: back <span class="hlt">pressure</span> turbine for geothermal <span class="hlt">vapor</span>-dominated system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alfandi Ahmad, Angga; Xaverius Guwowijoyo, Fransiscus; Pratama, Heru Berian</p> <p>2017-12-01</p> <p>Geothermal bussiness nowadays needs to be accelerated in a way that profit can be obtained as soon as reasonable possible. One of the many ways to do this is by using one of geothermal wellhead generating unit (GWGU), called backpressure turbine. Backpressure turbine can be used in producing electricity as soon as there is productive or rather small-scale productive well existed after finished drilling. In a <span class="hlt">vapor</span> dominated system, steam fraction in the wellhead capable to produce electricity based on each well productivity immediately. The advantage for using <span class="hlt">vapor</span> dominated system is reduce brine disposal in the wellhead so it will be a cost benefit in operation. The design and calculation for backpressure turbine will use probablistic approach with Monte Carlo simulation. The parameter that will be evaluated in sensitivity would be steam flow rate, turbine inlet <span class="hlt">pressure</span>, and turbine exhaust <span class="hlt">pressure</span>/atmospheric <span class="hlt">pressure</span>. The result are probability for P10, P50, and P90 of gross power output which are 1.78 MWe, 2.22 MWe and 2.66 Mwe respectively. Whereas the P10, P50, and P90 of SSC are 4.67 kg/s/MWe, 5.19 kg/s/MWe and 5.78 kg/s/MWe respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70179130','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70179130"><span>Barrier island breach evolution: Alongshore transport and bay-ocean <span class="hlt">pressure</span> <span class="hlt">gradient</span> interactions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Safak, Ilgar; Warner, John C.; List, Jeffrey</p> <p>2016-01-01</p> <p>Physical processes controlling repeated openings and closures of a barrier island breach between a bay and the open ocean are studied using aerial photographs and atmospheric and hydrodynamic observations. The breach site is located on Pea Island along the Outer Banks, separating Pamlico Sound from the Atlantic Ocean. Wind direction was a major control on the <span class="hlt">pressure</span> <span class="hlt">gradients</span> between the bay and the ocean to drive flows that initiate or maintain the breach opening. Alongshore sediment flux was found to be a major contributor to breach closure. During the analysis period from 2011 to 2016, three hurricanes had major impacts on the breach. First, Hurricane Irene opened the breach with wind-driven flow from bay to ocean in August 2011. Hurricane Sandy in October 2012 quadrupled the channel width from <span class="hlt">pressure</span> <span class="hlt">gradient</span> flows due to water levels that were first higher on the ocean side and then higher on the bay side. The breach closed sometime in Spring 2013, most likely due to an event associated with strong alongshore sediment flux but minimal ocean-bay <span class="hlt">pressure</span> <span class="hlt">gradients</span>. Then, in July 2014, Hurricane Arthur briefly opened the breach again from the bay side, in a similar fashion to Irene. In summary, opening and closure of breaches are shown to follow a dynamic and episodic balance between along-channel <span class="hlt">pressure</span> <span class="hlt">gradient</span> driven flows and alongshore sediment fluxes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16321097','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16321097"><span>Characterization of the TIP4P-Ew water model: <span class="hlt">vapor</span> <span class="hlt">pressure</span> and boiling point.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Horn, Hans W; Swope, William C; Pitera, Jed W</p> <p>2005-11-15</p> <p>The liquid-<span class="hlt">vapor</span>-phase equilibrium properties of the previously developed TIP4P-Ew water model have been studied using thermodynamic integration free-energy simulation techniques in the temperature range of 274-400 K. We stress that free-energy results from simulations need to be corrected in order to be compared to the experiment. This is due to the fact that the thermodynamic end states accessible through simulations correspond to fictitious substances (classical rigid liquids and classical rigid ideal gases) while experiments operate on real substances (liquids and real gases, with quantum effects). After applying analytical corrections the <span class="hlt">vapor</span> <span class="hlt">pressure</span> curve obtained from simulated free-energy changes is in excellent agreement with the experimental <span class="hlt">vapor</span> <span class="hlt">pressure</span> curve. The boiling point of TIP4P-Ew water under ambient <span class="hlt">pressure</span> is found to be at 370.3+/-1.9 K, about 7 K higher than the boiling point of TIP4P water (363.7+/-5.1 K; from simulations that employ finite range treatment of electrostatic and Lennard-Jones interactions). This is in contrast to the approximately +15 K by which the temperature of the density maximum and the melting temperature of TIP4P-Ew are shifted relative to TIP4P, indicating that the temperature range over which the liquid phase of TIP4P-Ew is stable is narrower than that of TIP4P and resembles more that of real water. The quality of the <span class="hlt">vapor</span> <span class="hlt">pressure</span> results highlights the success of TIP4P-Ew in describing the energetic and entropic aspects of intermolecular interactions in liquid water.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29196341','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29196341"><span><span class="hlt">Vapor</span> <span class="hlt">pressure</span> deficit predicts epiphyte abundance across an elevational <span class="hlt">gradient</span> in a tropical montane region.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gotsch, Sybil G; Davidson, Kenneth; Murray, Jessica G; Duarte, Vanessa J; Draguljić, Danel</p> <p>2017-12-01</p> <p>Tropical Montane Cloud Forests (TMCFs) are important ecosystems to study and preserve because of their high biodiversity and critical roles in local and regional ecosystem processes. TMCFs may be particularly affected by changes in climate because of the narrow bands of microclimate they occupy and the vulnerability of TMCF species to projected increases in cloud base heights and drought. A comprehensive understanding of the structure and function of TMCFs is lacking and difficult to attain because of variation in topography within and across TMCF sites. This causes large differences in microclimate and forest structure at both large and small scales. In this study, we estimated the abundance of the entire epiphyte community in the canopy (bryophytes, herbaceous vascular plants, woody epiphytes, and canopy dead organic matter) in six sites. In each of the sites we installed a complete canopy weather station to link epiphyte abundance to a number of microclimatic parameters. We found significant differences in epiphyte abundance across the sites; epiphyte abundance increased with elevation and leaf wetness, but decreased as <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit (VPD) increased. Epiphyte abundance had the strongest relationship with VPD; there were differences in VPD that could not be explained by elevation alone. By measuring this proxy of canopy VPD, TMCF researchers will better understand differences in microclimate and plant community composition across TMCF sites. Incorporating such information in comparative studies will allow for more meaningful comparisons across TMCFs and will further conservation and management efforts in this ecosystem. © 2017 Botanical Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18344074','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18344074"><span>Relationship between the evaporation rate and <span class="hlt">vapor</span> <span class="hlt">pressure</span> of moderately and highly volatile chemicals.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>van Wesenbeeck, Ian; Driver, Jeffrey; Ross, John</p> <p>2008-04-01</p> <p>Volatilization of chemicals can be an important form of dissipation in the environment. Rates of evaporative losses from plant and soil surfaces are useful for estimating the potential for food-related dietary residues and operator and bystander exposure, and can be used as source functions for screening models that predict off-site movement of volatile materials. A regression of evaporation on <span class="hlt">vapor</span> <span class="hlt">pressure</span> from three datasets containing 82 pesticidal active ingredients and co-formulants, ranging in <span class="hlt">vapor</span> <span class="hlt">pressure</span> from 0.0001 to >30,000 Pa was developed for this purpose with a regression correlation coefficient of 0.98.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29770413','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29770413"><span>Effect of <span class="hlt">pressure</span> <span class="hlt">gradient</span> and new phases for 1,3,5-trinitrohexahydro-s-triazine (RDX) under high <span class="hlt">pressures</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gao, Chan; Zhang, Xueyong; Zhang, Chuanchao; Sui, Zhilei; Hou, Meng; Dai, Rucheng; Wang, Zhongping; Zheng, Xianxu; Zhang, Zengming</p> <p>2018-05-17</p> <p>Herein, <span class="hlt">pressure</span>-induced phase transitions of RDX up to 50 GPa were systematically studied under different compression conditions. Precise phase transition points were obtained based on high-quality Raman spectra with small <span class="hlt">pressure</span> intervals. This favors the correctness of the theoretical formula for detonation and the design of a precision weapon. The experimental results indicated that α-RDX immediately transformed to γ-RDX at 3.5 GPa due to hydrostatic conditions and possible interaction between the penetrating helium and RDX, with helium gas as the <span class="hlt">pressure</span>-transmitting medium (PTM). Mapping of <span class="hlt">pressure</span> distribution in samples demonstrates that the <span class="hlt">pressure</span> <span class="hlt">gradient</span> is generated in the chamber and independent of other PTMs. The <span class="hlt">gradient</span> induced the first phase transition starts at 2.3 GPa and completed at 4.1 GPa. The larger <span class="hlt">pressure</span> <span class="hlt">gradient</span> promoted phase transition in advance under higher <span class="hlt">pressures</span>. Experimental results supported that there existed two conformers of AAI and AAE for γ-RDX, as proposed by another group. δ-RDX was considered to only occur in a hydrostatic environment around 18 GPa using helium as the PTM. This study confirms that δ-RDX is independent of PTM and exists under non-hydrostatic conditions. Evidence for a new phase (ζ) was found at about 28 GPa. These 4 phases have also been verified via XRD under high <span class="hlt">pressures</span>. In addition to this, another new phase (η) may exist above 38 GPa, and it needs to be further confirmed in the future. Moreover, all the phase transitions were reversible after the <span class="hlt">pressure</span> was released, and original α-RDX was always obtained at ambient <span class="hlt">pressure</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8759E..33F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8759E..33F"><span><span class="hlt">Pressure</span> intelligent control strategy of Waste heat recovery system of converter <span class="hlt">vapors</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, Xugang; Wu, Zhiwei; Zhang, Jiayan; Qian, Hong</p> <p>2013-01-01</p> <p>The converter gas evaporative cooling system is mainly used for absorbing heat in the high temperature exhaust gas which produced by the oxygen blowing reaction. <span class="hlt">Vaporization</span> cooling steam <span class="hlt">pressure</span> control system of converter is a nonlinear, time-varying, lagging behind, close coupling of multivariable control object. This article based on the analysis of converter operation characteristics of evaporation cooling system, of <span class="hlt">vaporization</span> in a production run of pipe <span class="hlt">pressure</span> variation and disturbance factors.For the dynamic characteristics of the controlled objects,we have improved the conventional PID control scheme.In Oxygen blowing process, we make intelligent control by using fuzzy-PID cascade control method and adjusting the Lance,that it can realize the optimization of the boiler steam <span class="hlt">pressure</span> control.By design simulation, results show that the design has a good control not only ensures drum steam <span class="hlt">pressure</span> in the context of security, enabling efficient conversion of waste heat.And the converter of 1800 flue gas through pipes and cool and dust removal also can be cooled to about 800. Therefore the converter haze evaporative cooling system has achieved to the converter haze temperature decrease effect and enhanced to the coal gas returns-ratio.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70194566','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70194566"><span>Contaminant <span class="hlt">gradients</span> in trees: Directional tree coring reveals boundaries of soil and soil-gas contamination with potential applications in <span class="hlt">vapor</span> intrusion assessment</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wilson, Jordan L.; Samaranayake, V.A.; Limmer, Matthew A.; Schumacher, John G.; Burken, Joel G.</p> <p>2017-01-01</p> <p>Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate <span class="hlt">gradients</span> in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration <span class="hlt">gradients</span> (spearman’s coefficient of -0.61 and -0.55 in soil and tree-core <span class="hlt">gradients</span>, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in-planta and soil concentration <span class="hlt">gradients</span> and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and <span class="hlt">vapor</span> intrusion, this study also indicates that directional tree coring might be applicable in <span class="hlt">vapor</span> intrusion assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29182871','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29182871"><span>Contaminant <span class="hlt">Gradients</span> in Trees: Directional Tree Coring Reveals Boundaries of Soil and Soil-Gas Contamination with Potential Applications in <span class="hlt">Vapor</span> Intrusion Assessment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilson, Jordan L; Samaranayake, V A; Limmer, Matthew A; Schumacher, John G; Burken, Joel G</p> <p>2017-12-19</p> <p>Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate <span class="hlt">gradients</span> in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration <span class="hlt">gradients</span> (spearman's coefficient of -0.61 and -0.55 in soil and tree-core <span class="hlt">gradients</span>, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in planta and soil concentration <span class="hlt">gradients</span> and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and <span class="hlt">vapor</span> intrusion, this study also indicates that directional tree coring might be applicable in <span class="hlt">vapor</span> intrusion assessment.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920052415&hterms=weather+map+humidity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dweather%2Bmap%2Bhumidity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920052415&hterms=weather+map+humidity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dweather%2Bmap%2Bhumidity"><span>Surface <span class="hlt">pressure</span> maps from scatterometer data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brown, R. A.; Levy, Gad</p> <p>1991-01-01</p> <p>The ability to determine surface <span class="hlt">pressure</span> fields from satellite scatterometer data was shown by Brown and Levy (1986). The surface winds are used to calculate the <span class="hlt">gradient</span> winds above the planetary boundary layer, and these are directly related to the <span class="hlt">pressure</span> <span class="hlt">gradients</span>. There are corrections for variable stratification, variable surface roughness, horizontal inhomogeneity, humidity and baroclinity. The Seasat-A Satellite Scatterometer (SASS) data have been used in a systematic study of 50 synoptic weather events (regions of approximately 1000 X 1000 km). The preliminary statistics of agreement with national weather service surface <span class="hlt">pressure</span> maps are calculated. The resulting surface <span class="hlt">pressure</span> maps can be used together with SASS winds and Scanning Multichannel Microwave Radiometer (SMMR) water <span class="hlt">vapor</span> and liquid water analyses to provide good front and storm system analyses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/20000370-investigations-dc-electrical-discharges-low-pressure-sodium-vapor-implications-amtec-converters','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/20000370-investigations-dc-electrical-discharges-low-pressure-sodium-vapor-implications-amtec-converters"><span>Investigations of dc electrical discharges in low-<span class="hlt">pressure</span> sodium <span class="hlt">vapor</span> with implications for AMTEC converters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Barkan, A.; Hunt, T.K.</p> <p>1998-07-01</p> <p>Upcoming designs for AMTEC modules capable of delivering as much as 150 watts will see the introduction of higher voltages into sodium <span class="hlt">vapor</span> at <span class="hlt">pressures</span> spanning a wide range. In theory, with any value for two out of three parameters: voltage, <span class="hlt">pressure</span>, and electrode geometry, a value exists for the third parameter where DC electrical breakdown can occur; due to its low ionization energy, sodium <span class="hlt">vapor</span> may be particularly susceptible to breakdown. This destructive event is not desirable in AMTEC modules, and sets a limit on the maximum voltage that can be built-up within any single enclosed module. An experimentalmore » cell was fabricated with representative electrode configurations and a separately heated sodium reservoir to test conditions typically expected during start-up, operation, and shutdown of AMTEC cells. Breakdown voltages were investigated in both sodium <span class="hlt">vapor</span> and, for comparison, argon gas. The dependence on electrode material and polarity was also investigated. Additional information about leakage currents and the insulating properties of {alpha}-alumina in the presence of sodium <span class="hlt">vapor</span> was collected, revealing a reversible tendency for conductive sodium films to build up under certain conditions, electrically shorting-out previously isolated components. In conclusion, safe operating limits on voltages, temperatures, and <span class="hlt">pressures</span> are discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27273974','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27273974"><span>Determination of Water <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> Over Corrosive Chemicals Versus Temperature Using Raman Spectroscopy as Exemplified with 85.5% Phosphoric Acid.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rodier, Marion; Li, Qingfeng; Berg, Rolf Willestofte; Bjerrum, Niels Janniksen</p> <p>2016-07-01</p> <p>A method to determine the water <span class="hlt">vapor</span> <span class="hlt">pressure</span> over a corrosive substance was developed and tested with 85.5 ± 0.4% phosphoric acid. The water <span class="hlt">vapor</span> <span class="hlt">pressure</span> was obtained at a range of temperatures from ∼25 ℃ to ∼200 ℃ using Raman spectrometry. The acid was placed in an ampoule and sealed with a reference gas (either hydrogen or methane) at a known <span class="hlt">pressure</span> (typically ∼0.5 bar). By comparing the Raman signals from the water <span class="hlt">vapor</span> and the references, the water <span class="hlt">pressure</span> was determined as a function of temperature. A considerable amount of data on the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of phosphoric acid are available in the literature, to which our results could successfully be compared. A record value of the <span class="hlt">vapor</span> <span class="hlt">pressure</span>, 3.40 bar, was determined at 210 ℃. The method required a determination of the precise Raman scattering ratios between the substance, water, and the used reference gas, hydrogen or methane. In our case the scattering ratios between water and reference ν1 Q-branches were found to be 1.20 ± 0.03 and 0.40 ± 0.02 for H2 and CH4, respectively. © The Author(s) 2016.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018HMT...tmp..112M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018HMT...tmp..112M"><span>Experimental study on the performance of the <span class="hlt">vapor</span> injection refrigeration system with an economizer for intermediate <span class="hlt">pressures</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moon, Chang-Uk; Choi, Kwang-Hwan; Yoon, Jung-In; Kim, Young-Bok; Son, Chang-Hyo; Ha, Soo-Jung; Jeon, Min-Ju; An, Sang-Young; Lee, Joon-Hyuk</p> <p>2018-04-01</p> <p>In this study, to investigate the performance characteristics of <span class="hlt">vapor</span> injection refrigeration system with an economizer at an intermediate <span class="hlt">pressure</span>, the <span class="hlt">vapor</span> injection refrigeration system was analyzed under various experiment conditions. As a result, the optimum design data of the <span class="hlt">vapor</span> injection refrigeration system with an economizer were obtained. The findings from this study can be summarized as follows. The mass flow rate through the compressor increases with intermediate <span class="hlt">pressure</span>. The compression power input showed an increasing trend under all the test conditions. The evaporation capacity increased and then decreased at the intermediate <span class="hlt">pressure</span>, and as such, it became maximum at the given intermediate <span class="hlt">pressure</span>. The increased mass flow rate of the by-passed refrigerant enhanced the evaporation capacity at the low medium <span class="hlt">pressure</span> range, but the increased saturation temperature limited the subcooling degree of the liquid refrigerant after the application of the economizer when the intermediate <span class="hlt">pressure</span> kept rising, and degenerated the evaporation capacity. The coefficient of performance (COP) increased and then decreased with respect to the intermediate <span class="hlt">pressures</span> under all the experiment conditions. Nevertheless, there was an optimum intermediate <span class="hlt">pressure</span> for the maximum COP under each experiment condition. Therefore, the optimum intermediate <span class="hlt">pressure</span> in this study was found at -99.08 kPa, which is the theoretical standard medium <span class="hlt">pressure</span> under all the test conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70124304','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70124304"><span>Water-<span class="hlt">vapor</span> <span class="hlt">pressure</span> in nests of the San Miguel Island Song Sparrow</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kern, Michael D.; Sogge, Mark K.; van Riper, Charles</p> <p>1990-01-01</p> <p>The water-<span class="hlt">vapor</span> <span class="hlt">pressure</span> (PN) in nests of the San Miguel Island race of Song Sparrows (Melospiza melodia micronyx) averaged 16 torr, but varied considerable between nests and within individual nests during successive days of incubation. Large daily fluctuations occurred throughout the incubation period and did not parallel concurrent changes in ambien <span class="hlt">vapor</span> <span class="hlt">pressure</span> (P1). Daily rates of water loss from nest eggs (MH2O) averaged 28 mg day-1, but also varied considerable within and between nests and did not correlate with changes in P1. MH2O increased 6-33% after the third day of incubation. PN was significantly higher and MH2O significantly lower in nests located in sheltered gullies than in nests from a windswept slope. These data suggest that Song Sparrows do not regulate PN to achieve hatching success.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20969399','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20969399"><span>Performance of some nucleation theories with a nonsharp droplet-<span class="hlt">vapor</span> interface.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Napari, Ismo; Julin, Jan; Vehkamäki, Hanna</p> <p>2010-10-21</p> <p>Nucleation theories involving the concept of nonsharp boundary between the droplet and <span class="hlt">vapor</span> are compared to recent molecular dynamics (MD) simulation data of Lennard-Jones <span class="hlt">vapors</span> at temperatures above the triple point. The theories are diffuse interface theory (DIT), extended modified liquid drop-dynamical nucleation theory (EMLD-DNT), square <span class="hlt">gradient</span> theory (SGT), and density functional theory (DFT). Particular attention is paid to thermodynamic consistency in the comparison: the applied theories either use or, with a proper parameter adjustment, result in the same values of equilibrium <span class="hlt">vapor</span> <span class="hlt">pressure</span>, bulk liquid density, and surface tension as the MD simulations. Realistic <span class="hlt">pressure</span>-density correlations are also used. The best agreement between the simulated nucleation rates and calculations is obtained from DFT, SGT, and EMLD-DNT, all of which, in the studied temperature range, show deviations of less than one order of magnitude in the nucleation rate. DIT underestimates the nucleation rate by up to two orders of magnitude. DFT and SGT give the best estimate of the molecular content of the critical nuclei. Overall, at the <span class="hlt">vapor</span> conditions of this study, all the investigated theories perform better than classical nucleation theory in predicting nucleation rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MMTA...47.5569M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MMTA...47.5569M"><span>Modeling the Capillary <span class="hlt">Pressure</span> for the Migration of the Liquid Phase in Granular Solid-Liquid-<span class="hlt">Vapor</span> Systems: Application to the Control of the Composition Profile in W-Cu FGM Materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Missiaen, Jean-Michel; Raharijaona, Jean-Joël; Delannay, Francis</p> <p>2016-11-01</p> <p>A model is developed to compute the capillary <span class="hlt">pressure</span> for the migration of the liquid phase out or into a uniform solid-liquid-<span class="hlt">vapor</span> system. The capillary <span class="hlt">pressure</span> is defined as the reduction of the overall interface energy per volume increment of the transferred fluid phase. The model takes into account the particle size of the solid particle aggregate, the packing configuration (coordination number, porosity), the volume fractions of the different phases, and the values of the interface energies in the system. The model is used for analyzing the stability of the composition profile during processing of W-Cu functionally graded materials combining a composition <span class="hlt">gradient</span> with a particle size <span class="hlt">gradient</span>. The migration <span class="hlt">pressure</span> is computed with the model in two stages: (1) just after the melting of copper, i.e., when sintering and shape accommodation of the W particle aggregate can still be neglected and (2) at high temperature, when the system is close to full density with equilibrium particle shape. The model predicts well the different stages of liquid-phase migration observed experimentally.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990040250','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990040250"><span>Chemical <span class="hlt">Vapor</span> Deposition at High <span class="hlt">Pressure</span> in a Microgravity Environment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McCall, Sonya; Bachmann, Klaus; LeSure, Stacie; Sukidi, Nkadi; Wang, Fuchao</p> <p>1999-01-01</p> <p>In this paper we present an evaluation of critical requirements of organometallic chemical <span class="hlt">vapor</span> deposition (OMCVD) at elevated <span class="hlt">pressure</span> for a channel flow reactor in a microgravity environment. The objective of using high <span class="hlt">pressure</span> is to maintain single-phase surface composition for materials that have high thermal decomposition <span class="hlt">pressure</span> at their optimum growth temperature. Access to microgravity is needed to maintain conditions of laminar flow, which is essential for process analysis. Based on ground based observations we present an optimized reactor design for OMCVD at high <span class="hlt">pressure</span> and reduced gravity. Also, we discuss non-intrusive real-time optical monitoring of flow dynamics coupled to homogeneous gas phase reactions, transport and surface processes. While suborbital flights may suffice for studies of initial stages of heteroepitaxy experiments in space are essential for a complete evaluation of steady-state growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JPhCS1001a2020S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JPhCS1001a2020S"><span>Characterisation of minimal-span plane Couette turbulence with <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sekimoto, Atsushi; Atkinson, Callum; Soria, Julio</p> <p>2018-04-01</p> <p>The turbulence statistics and dynamics in the spanwise-minimal plane Couette flow with <span class="hlt">pressure</span> <span class="hlt">gradients</span>, so-called, Couette-Poiseuille (C-P) flow, are investigated using direct numerical simulation. The large-scale motion is limited in the spanwise box dimension as in the minimal-span channel turbulence of Flores & Jiménez (Phys. Fluids, vol. 22, 2010, 071704). The effect of the top wall, where normal <span class="hlt">pressure</span>-driven Poiseuille flow is realised, is distinguished from the events on the bottom wall, where the <span class="hlt">pressure</span> <span class="hlt">gradient</span> results in mild or almost-zero wall-shear stress. A proper scaling of turbulence statistics in minimal-span C-P flows is presented. Also the ‘shear-less’ wall-bounded turbulence, where the Corrsin shear parameter is very weak compared to normal wall-bounded turbulence, represents local separation, which is also observed as spanwise streaks of reversed flow in full-size plane C-P turbulence. The local separation is a multi-scale event, which grows up to the order of the channel height even in the minimal-span geometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70031066','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70031066"><span>A unified equation for calculating methane <span class="hlt">vapor</span> <span class="hlt">pressures</span> in the CH4-H2O system with measured Raman shifts</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lu, W.; Chou, I.-Ming; Burruss, R.C.; Song, Y.</p> <p>2007-01-01</p> <p>A unified equation has been derived by using all available data for calculating methane <span class="hlt">vapor</span> <span class="hlt">pressures</span> with measured Raman shifts of C-H symmetric stretching band (??1) in the <span class="hlt">vapor</span> phase of sample fluids near room temperature. This equation eliminates discrepancies among the existing data sets and can be applied at any Raman laboratory. Raman shifts of C-H symmetric stretching band of methane in the <span class="hlt">vapor</span> phase of CH4-H2O mixtures prepared in a high-<span class="hlt">pressure</span> optical cell were also measured at temperatures between room temperature and 200 ??C, and <span class="hlt">pressures</span> up to 37 MPa. The results show that the CH4 ??1 band position shifts to higher wavenumber as temperature increases. We also demonstrated that this Raman band shift is a simple function of methane <span class="hlt">vapor</span> density, and, therefore, when combined with equation of state of methane, methane <span class="hlt">vapor</span> <span class="hlt">pressures</span> in the sample fluids at elevated temperatures can be calculated from measured Raman peak positions. This method can be applied to determine the <span class="hlt">pressure</span> of CH4-bearing systems, such as methane-rich fluid inclusions from sedimentary basins or experimental fluids in hydrothermal diamond-anvil cell or other types of optical cell. ?? 2007 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16851662','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16851662"><span>On the critical temperature, normal boiling point, and <span class="hlt">vapor</span> <span class="hlt">pressure</span> of ionic liquids.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rebelo, Luis P N; Canongia Lopes, José N; Esperança, José M S S; Filipe, Eduardo</p> <p>2005-04-07</p> <p>One-stage, reduced-<span class="hlt">pressure</span> distillations at moderate temperature of 1-decyl- and 1-dodecyl-3-methylimidazolium bistriflilamide ([Ntf(2)](-)) ionic liquids (ILs) have been performed. These liquid-<span class="hlt">vapor</span> equilibria can be understood in light of predictions for normal boiling points of ILs. The predictions are based on experimental surface tension and density data, which are used to estimate the critical points of several ILs and their corresponding normal boiling temperatures. In contrast to the situation found for relatively unstable ILs at high-temperature such as those containing [BF(4)](-) or [PF(6)](-) anions, [Ntf(2)](-)-based ILs constitute a promising class in which reliable, accurate <span class="hlt">vapor</span> <span class="hlt">pressure</span> measurements can in principle be performed. This property is paramount for assisting in the development and testing of accurate molecular models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDA24008M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDA24008M"><span>Evaluation of the accuracy of the Rotating Parallel Ray Omnidirectional Integration for instantaneous <span class="hlt">pressure</span> reconstruction from the measured <span class="hlt">pressure</span> <span class="hlt">gradient</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moreto, Jose; Liu, Xiaofeng</p> <p>2017-11-01</p> <p>The accuracy of the Rotating Parallel Ray omnidirectional integration for <span class="hlt">pressure</span> reconstruction from the measured <span class="hlt">pressure</span> <span class="hlt">gradient</span> (Liu et al., AIAA paper 2016-1049) is evaluated against both the Circular Virtual Boundary omnidirectional integration (Liu and Katz, 2006 and 2013) and the conventional Poisson equation approach. Dirichlet condition at one boundary point and Neumann condition at all other boundary points are applied to the Poisson solver. A direct numerical simulation database of isotropic turbulence flow (JHTDB), with a homogeneously distributed random noise added to the entire field of DNS <span class="hlt">pressure</span> <span class="hlt">gradient</span>, is used to assess the performance of the methods. The random noise, generated by the Matlab function Rand, has a magnitude varying randomly within the range of +/-40% of the maximum DNS <span class="hlt">pressure</span> <span class="hlt">gradient</span>. To account for the effect of the noise distribution pattern on the reconstructed <span class="hlt">pressure</span> accuracy, a total of 1000 different noise distributions achieved by using different random number seeds are involved in the evaluation. Final results after averaging the 1000 realizations show that the error of the reconstructed <span class="hlt">pressure</span> normalized by the DNS <span class="hlt">pressure</span> variation range is 0.15 +/-0.07 for the Poisson equation approach, 0.028 +/-0.003 for the Circular Virtual Boundary method and 0.027 +/-0.003 for the Rotating Parallel Ray method, indicating the robustness of the Rotating Parallel Ray method in <span class="hlt">pressure</span> reconstruction. Sponsor: The San Diego State University UGP program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150003230','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150003230"><span>Integrated Rig for the Production of Boron Nitride Nanotubes via the <span class="hlt">Pressurized</span> <span class="hlt">Vapor</span>-Condenser Method</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor)</p> <p>2014-01-01</p> <p>An integrated production apparatus for production of boron nitride nanotubes via the <span class="hlt">pressure</span> <span class="hlt">vapor</span>-condenser method. The apparatus comprises: a <span class="hlt">pressurized</span> reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of <span class="hlt">pressurized</span> nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the <span class="hlt">pressurized</span> reaction chamber containing a target feed system and a laser beam and optics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1128685','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/1128685"><span>Integrated rig for the production of boron nitride nanotubes via the <span class="hlt">pressurized</span> <span class="hlt">vapor</span>-condenser method</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Smith, Michael W; Jordan, Kevin C</p> <p>2014-03-25</p> <p>An integrated production apparatus for production of boron nitride nanotubes via the <span class="hlt">pressure</span> <span class="hlt">vapor</span>-condenser method. The apparatus comprises: a <span class="hlt">pressurized</span> reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of <span class="hlt">pressurized</span> nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the <span class="hlt">pressurized</span> reaction chamber containing a target feed system and a laser beam and optics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol15/pdf/CFR-2010-title40-vol15-sec65-111.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol15/pdf/CFR-2010-title40-vol15-sec65-111.pdf"><span>40 CFR 65.111 - Standards: <span class="hlt">Pressure</span> relief devices in gas/<span class="hlt">vapor</span> service.</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>2010-07-01</p> <p>... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: <span class="hlt">Pressure</span> relief devices in gas/<span class="hlt">vapor</span> service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.111 Standards...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/20020843-subatmospheric-vapor-pressures-fluoromethane-r41-difluoroethane-r152a-trifluoroethane-r143a-evaluated-from-internal-energy-measurements','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/20020843-subatmospheric-vapor-pressures-fluoromethane-r41-difluoroethane-r152a-trifluoroethane-r143a-evaluated-from-internal-energy-measurements"><span>Subatmospheric <span class="hlt">vapor</span> <span class="hlt">pressures</span> for fluoromethane (R41), 1,1-difluoroethane (R152a), and 1,1,1-trifluoroethane (R143a) evaluated from internal-energy measurements</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Duarte-Garza, H.A.; Magee, J.W.</p> <p>1999-09-01</p> <p><span class="hlt">Vapor</span> <span class="hlt">pressures</span> were evaluated from measured internal-energy changes {Delta}U{sup (2)} in the <span class="hlt">vapor</span> + liquid two-phase region. The method employed a thermodynamic relationship between the derivative quantity ({partial_derivative}U{sup (2)}/{partial_derivative}V){sub T}, the <span class="hlt">vapor</span> <span class="hlt">pressure</span> p{sub {sigma}}, and its temperature derivative ({partial_derivative}p/{partial_derivative}T){sub {sigma}}. This method was applied at temperatures between the triple point and the normal boiling point of three substances: fluoromethane (R41), 1,1-difluoroethane (R152a), and 1,1,1-trifluoroethane (R143a). In the case of R41, <span class="hlt">vapor</span> <span class="hlt">pressures</span> up to 1 MPa were calculated to validate the technique at higher <span class="hlt">pressures</span>. For R152a, the calculated <span class="hlt">vapor</span> <span class="hlt">pressure</span> at the triple-point temperature differed from a directmore » experimental measurement by less than the claimed uncertainty (5 Pa) of the measurement. The calculated <span class="hlt">vapor</span> <span class="hlt">pressures</span> for R41 helped to resolve discrepancies in several published <span class="hlt">vapor</span> <span class="hlt">pressure</span> sources. Agreement with experimentally measured <span class="hlt">vapor</span> <span class="hlt">pressures</span> for R152a and for R143a near the normal boiling point (101.325 kPa) was within the experimental uncertainty of approximately 0.04 kPa (0.04%) for the published measurements.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1433222','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1433222"><span>Effect of Valsalva's manoeuvre and hyoscinbutylbromide on the <span class="hlt">pressure</span> <span class="hlt">gradient</span> across the wall of oesophageal varices.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hosking, S W; Robinson, P; Johnson, A G</p> <p>1987-01-01</p> <p>To assess whether Valsalva's manoeuvre might cause variceal bleeding, 22 patients with oesophageal varices were studied. In 12 patients who received no previous treatment to their varices the median <span class="hlt">pressure</span> <span class="hlt">gradient</span> across the varix wall at rest was 19 (6-36) mmHg, and in 10 patients whose varices were thrombosed at their distal end the median <span class="hlt">pressure</span> <span class="hlt">gradient</span> in the proximal patent varix was 8 (1-6) mmHg. In untreated patients groups, the <span class="hlt">pressure</span> <span class="hlt">gradient</span> rose by 6-12 mmHg during Valsalva's manoeuvre in four patients, fell by 4-11 mmHg in five patients and was virtually unchanged in the remainder. These changes seem unlikely to cause variceal bleeding. Patients who repeated Valsalva's manoeuvre showed similar changes on each occasion. Six patients in the untreated group also received hyoscinbutylbromide 20 mg iv. No change was seen in the <span class="hlt">pressure</span> <span class="hlt">gradient</span> in five patients, suggesting that it is of little value in preventing variceal bleeding. PMID:3500098</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780032176&hterms=water+pressure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dwater%2Bpressure','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780032176&hterms=water+pressure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dwater%2Bpressure"><span>Adiabatic <span class="hlt">pressure</span> dependence of the 2.7 and 1.9 micron water <span class="hlt">vapor</span> bands</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mathai, C. V.; Walls, W. L.; Broersma, S.</p> <p>1977-01-01</p> <p>An acoustic excitation technique is used to determine the adiabatic <span class="hlt">pressure</span> derivative of the spectral absorptance of the 2.7 and 1.9 micron water <span class="hlt">vapor</span> bands, and the 3.5 micron HCl band. The dependence of this derivative on thermodynamic parameters such as temperature, concentration, and <span class="hlt">pressure</span> is evaluated. A cross-flow water <span class="hlt">vapor</span> system is used to measure spectral absorptance. Taking F as the ratio of nonrigid to rotor line strengths, it is found that an F factor correction is needed for the 2.7 micron band. The F factor for the 1.9 micron band is also determined. In the wings of each band a wavelength can be found where the concentration dependence is predominant. Farther out in the wings a local maximum occurs for the temperature derivative. It is suggested that the <span class="hlt">pressure</span> derivative is significant in the core of the band.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1737d0007N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1737d0007N"><span>Effect of superficial velocity on <span class="hlt">vaporization</span> <span class="hlt">pressure</span> drop with propane in horizontal circular tube</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.</p> <p>2016-06-01</p> <p>Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on <span class="hlt">vaporization</span> <span class="hlt">pressure</span> drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing <span class="hlt">vapor</span> superficial velocity, and then increasing <span class="hlt">pressure</span> drop. The present experimental results were evaluated with some existing correlations of <span class="hlt">pressure</span> drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750006501','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750006501"><span>A model for jet-noise analysis using <span class="hlt">pressure-gradient</span> correlations on an imaginary cone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Norum, T. D.</p> <p>1974-01-01</p> <p>The technique for determining the near and far acoustic field of a jet through measurements of <span class="hlt">pressure-gradient</span> correlations on an imaginary conical surface surrounding the jet is discussed. The necessary analytical developments are presented, and their feasibility is checked by using a point source as the sound generator. The distribution of the apparent sources on the cone, equivalent to the point source, is determined in terms of the <span class="hlt">pressure-gradient</span> correlations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120012575','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120012575"><span><span class="hlt">Vapor</span> <span class="hlt">Pressure</span> and Evaporation Coefficient of Silicon Monoxide over a Mixture of Silicon and Silica</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ferguson, Frank T.; Nuth, Joseph A., III</p> <p>2012-01-01</p> <p>The evaporation coefficient and equilibrium <span class="hlt">vapor</span> <span class="hlt">pressure</span> of silicon monoxide over a mixture of silicon and vitreous silica have been studied over the temperature range (1433 to 1608) K. The evaporation coefficient for this temperature range was (0.007 plus or minus 0.002) and is approximately an order of magnitude lower than the evaporation coefficient over amorphous silicon monoxide powder and in general agreement with previous measurements of this quantity. The enthalpy of reaction at 298.15 K for this reaction was calculated via second and third law analyses as (355 plus or minus 25) kJ per mol and (363.6 plus or minus 4.1) kJ per mol respectively. In comparison with previous work with the evaporation of amorphous silicon monoxide powder as well as other experimental measurements of the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of silicon monoxide gas over mixtures of silicon and silica, these systems all tend to give similar equilibrium <span class="hlt">vapor</span> <span class="hlt">pressures</span> when the evaporation coefficient is correctly taken into account. This provides further evidence that amorphous silicon monoxide is an intimate mixture of small domains of silicon and silica and not strictly a true compound.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890005997','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890005997"><span>The influence of free-stream turbulence on turbulent boundary layers with mild adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoffmann, Jon A.</p> <p>1988-01-01</p> <p>The influence of near isotropic free-stream turbulence on the shape factors and skin friction coefficients of turbulent bounday layers is presented for the cases of zero and mild adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span>. With free-stream turbulence, improved fluid mixing occurs in boundary layers with adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> relative to the zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> condition, with the same free-stream turbulence intensity and length scale. Stronger boundary layers with lower shape factors occur as a result of a lower ratio of the integral scale of turbulence to the boundary layer thickness, and to vortex stretching of the turbulent eddies in the free stream, both of which act to improve the transmission of momentum from the free stream to the boundary layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890012674','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890012674"><span>The influence of free-stream turbulence on turbulent boundary layers with mild adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoffmann, J. A.; Kassir, S. M.; Larwood, S. M.</p> <p>1989-01-01</p> <p>The influence of near isotropic free-stream turbulence on the shape factors and skin friction coefficients of turbulent boundary layers is presented for the cases of zero and mild adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span>. With free-stream turbulence, improved fluid mixing occurs in boundary layers with adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> relative to the zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> condition, with the same free-stream turbulence intensity and length scale. Stronger boundary layers with lower shape factors occur as a result of a lower ratio of the integral scale of turbulence to the boundary layer thickness, and to vortex stretching of the turbulent eddies in the free-stream, both of which act to improve the transmission of momentum from the free-stream to the boundary layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26774257','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26774257"><span>Severity assessment of intracranial large artery stenosis by <span class="hlt">pressure</span> <span class="hlt">gradient</span> measurements: A feasibility study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Han, Yun-Fei; Liu, Wen-Hua; Chen, Xiang-Liang; Xiong, Yun-Yun; Yin, Qin-; Xu, Ge-Lin; Zhu, Wu-Sheng; Zhang, Ren-Liang; Ma, Min-Min; Li, Min-; Dai, Qi-Liang; Sun, Wen-; Liu, De-Zhi; Duan, Li-Hui; Liu, Xin-Feng</p> <p>2016-08-01</p> <p>Fractional flow reserve (FFR)-guided revascularization strategy is popular in coronary intervention. However, the feasibility of assessing stenotic severity in intracranial large arteries using <span class="hlt">pressure</span> <span class="hlt">gradient</span> measurements still remains unclear. Between March 2013 and May 2014, 12 consecutive patients with intracranial large artery stenosis (including intracranial internal carotid artery, middle cerebral M1 segment, intracranial vertebral artery, and basilar artery) were enrolled in this study. The trans-stenotic <span class="hlt">pressure</span> <span class="hlt">gradient</span> was measured before and/or after percutaneous transluminal angioplasty and stenting (PTAS), and was then compared with percent diameter stenosis. A Pd /Pa cut-off of ≤0.70 was used to guide stenting of hemodynamically significant stenoses. The device-related and procedure-related serious adverse events and recurrent cerebral ischemic events were recorded. The target vessel could be reached in all cases. No technical complications occurred due to the specific study protocol. Excellent <span class="hlt">pressure</span> signals were obtained in all patients. For seven patients who performed PTAS, the mean pre-procedural <span class="hlt">pressure</span> <span class="hlt">gradient</span> decreased from 59.0 ± 17.2 to 13.3 ± 13.6 mm Hg after the procedure (P < 0.01). Only one patient who refused stenting experienced a TIA event in the ipsilateral MCA territory. No recurrent ischemic event was observed in other patients. Mean trans-stenotic <span class="hlt">pressure</span> <span class="hlt">gradients</span> can be safely and easily measured with a 0.014-inch fluid-filled guide wire in intracranial large arteries. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28029367','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28029367"><span>On the feasibility to conduct <span class="hlt">gradient</span> liquid chromatography separations in narrow-bore columns at <span class="hlt">pressures</span> up to 2000bar.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Pauw, Ruben; Swier, Tim; Degreef, Bart; Desmet, Gert; Broeckhoven, Ken</p> <p>2016-11-18</p> <p>The limits in operating <span class="hlt">pressures</span> are extended for narrow-bore columns in <span class="hlt">gradient</span> elution up to 2000bar. As the required pumps for these <span class="hlt">pressures</span> are incompatible with common chromatographic solvents and are not suitable to apply a mobile phase composition <span class="hlt">gradient</span>, a mobile phase delivery and injection system is described and experimentally validated which allows to use any possible chromatographic solvent in isocratic and <span class="hlt">gradient</span> elution. The mobile phase delivery and injection system also allows to perform multiple separations without the need to depressurize the column. This system consists out of 5 dual on/off valves and two large volume loops in which the <span class="hlt">gradient</span> and equilibration volume of initial mobile phase are loaded by a commercial liquid chromatography pump. The loops are then flushed toward the column at extreme <span class="hlt">pressures</span>. The mobile phase delivery and injection system is first evaluated in isocratic elution and shows a comparable performance to a state-of-the-art commercial flow-through-needle injector but with twice the <span class="hlt">pressure</span> rating. Distortion of the loaded <span class="hlt">gradient</span> by dispersion in the <span class="hlt">gradient</span> storage loop is studied. The effect of the most important parameters (such as flow rate, <span class="hlt">pressure</span> and <span class="hlt">gradient</span> steepness) is experimentally investigated. Different <span class="hlt">gradient</span> steepnesses and volumes can be applied at different flow rates and operating <span class="hlt">pressures</span> with a good repeatability. Due to the isobaric operation of the pumps, the <span class="hlt">gradient</span> is monitored in real-time by a mass flow meter installed at the detector outlet. The chromatograms are then converted from time to volume-base. A separation of a 19-compound sample is performed on a 300×2.1mm column at 1000bar and on a 600×2.1mm column at 2000bar. The peak capacity was found to increase from 141 to 199 and thus scales with L as is predicted by theory. This allows to conclude that the inlet <span class="hlt">pressure</span> for narrow-bore columns in <span class="hlt">gradient</span> elution can be increased up to 2000bar without fundamental</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JNuM..456...17L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JNuM..456...17L"><span>In-reactor oxidation of zircaloy-4 under low water <span class="hlt">vapor</span> <span class="hlt">pressures</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.</p> <p>2015-01-01</p> <p>Complementary in- and ex-reactor oxidation tests have been performed to evaluate the oxidation and hydrogen absorption performance of Zircaloy-4 (Zr-4) under relatively low partial <span class="hlt">pressures</span> (300 and 1000 Pa) of water <span class="hlt">vapor</span> at specified test temperatures (330 and 370 °C). Data from these tests will be used to support the fabrication of components intended for isotope-producing targets and provide information regarding the temperature and <span class="hlt">pressure</span> dependence of oxidation and hydrogen absorption of Zr-4 over the specified range of test conditions. Comparisons between in- and ex-reactor test results were performed to evaluate the influence of irradiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT.......135D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT.......135D"><span><span class="hlt">Vapor</span> <span class="hlt">Pressure</span> Measurements of LiBH4, NaBH 4 and Ca(BH4)2 using Knudsen Torsion Effusion Gravimetric Method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Danyan, Mohammad Masoumi</p> <p></p> <p>Hydrogen storage is one of the critical technologies needed on the path towards commercialization for mobile applications. In the past few years, a range of new light weight hydrogen containing material has been discovered with good storage properties. Among them, lithium borohydride (LiBH 4) sodium borohydride (NaBH4) and calcium borohydride (Ca(BH 4)2) have shown promising results to be used as solid state hydrogen storage material. In this work, we have determined equilibrium <span class="hlt">vapor</span> <span class="hlt">pressures</span> of LiBH 4 NaBH4 and Ca(BH4)2 obtained by Torsion effusion thermogravimetric method. Results for all the three hydrides exhibited that a small fraction of the materials showed congruency, and sublimed as gaseous compound, but the majority of the material showed incongruent <span class="hlt">vaporization</span>. Two Knudsen cells of 0.3 and 0.6mm orifice size was employed to measure the total <span class="hlt">vapor</span> <span class="hlt">pressures</span>. A Whitman-Motzfeldt method is used to extrapolate the measured <span class="hlt">vapor</span> <span class="hlt">pressures</span> to zero orifice size to calculate the equilibrium <span class="hlt">vapor</span> <span class="hlt">pressures</span>. In the case of LiBH4 we found that 2% of the material evaporated congruently (LiBH4(s) → LiBH4(g)) according to the equation: logPLiBH4/P 0 =-3263.5 +/-309/T + (1.079 +/-0.69) and rest as incongruent <span class="hlt">vaporization</span> to LiH, B, and hydrogen gas according to the equation logPeq/P0 =(-3263.5 +/-309)/T+ (2.458 +/-0.69) with DeltaH evap.= 62.47+/-5.9 kJ/mol of H2, DeltaSevap. = 47.05+/-13 J/mol of H2.K. The NaBH4 also had somewhat similar behavior, with 9% congruent evaporation and equilibrium <span class="hlt">vapor</span> <span class="hlt">pressure</span> equation of logPLiBH4=-7700+/-335/ T+ (6.7+/-1.5) and 91% incongruent decomposition to Na and Boron metal, and hydrogen gas. The enthalpy of <span class="hlt">vaporization</span>; DeltaHevap. = 147.2+/-6.4kJ/molH2 and DeltaSevap.= 142 +/-28 kJ/molH2.K (550-650K). The Ca(BH4) 2 exhibited similar <span class="hlt">vaporization</span> behavior with congruency of 3.2%. The decomposition products are CaH2 and Boron metal with evolution of hydrogen gas varying with the <span class="hlt">pressure</span> equation as logPeq /P0 =(-1562</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5479527','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5479527"><span>Hemodynamic and metabolic characteristics associated with development of a right ventricular outflow tract <span class="hlt">pressure</span> <span class="hlt">gradient</span> during upright exercise</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>van Riel, Annelieke C. M. J.; Systrom, David M.; Oliveira, Rudolf K. F.; Landzberg, Michael J.; Mulder, Barbara J. M.; Bouma, Berto J.; Maron, Bradley A.; Shah, Amil M.; Waxman, Aaron B.</p> <p>2017-01-01</p> <p>Background We recently reported a novel observation that many patients with equal resting supine right ventricular(RV) and pulmonary artery(PA) systolic <span class="hlt">pressures</span> develop an RV outflow tract(RVOT) <span class="hlt">pressure</span> <span class="hlt">gradient</span> during upright exercise. The current work details the characteristics of patients who develop such an RVOT <span class="hlt">gradient</span>. Methods We studied 294 patients (59.7±15.5 years-old, 49% male) referred for clinical invasive cardiopulmonary exercise testing, who did not have a resting RVOT <span class="hlt">pressure</span> <span class="hlt">gradient</span> defined by the simultaneously measured peak-to-peak difference between RV and PA systolic <span class="hlt">pressures</span>. Results The magnitude of RVOT <span class="hlt">gradient</span> did not correspond to clinical or hemodynamic findings suggestive of right heart failure; rather, higher <span class="hlt">gradients</span> were associated with favorable exercise findings. The presence of a high peak RVOT <span class="hlt">gradient</span> (90th percentile, ≥33mmHg) was associated with male sex (70 vs. 46%, p = 0.01), younger age (43.6±17.7 vs. 61.8±13.9 years, p<0.001), lower peak right atrial <span class="hlt">pressure</span> (5 [3–7] vs. 8 [4–12]mmHg, p<0.001), higher peak heart rate (159±19 vs. 124±26 beats per minute, p<0.001), and higher peak cardiac index (8.3±2.3 vs. 5.7±1.9 L/min/m2, p<0.001). These associations persisted when treating peak RVOT as a continuous variable and after age and sex adjustment. At peak exercise, patients with a high exercise RVOT <span class="hlt">gradient</span> had both higher RV systolic <span class="hlt">pressure</span> (78±11 vs. 66±17 mmHg, p<0.001) and lower PA systolic <span class="hlt">pressure</span> (34±8 vs. 50±19 mmHg, p<0.001). Conclusions Development of a systolic RV-PA <span class="hlt">pressure</span> <span class="hlt">gradient</span> during upright exercise is not associated with an adverse hemodynamic exercise response and may represent a normal physiologic finding in aerobically fit young people. PMID:28636647</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29753461','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29753461"><span>Hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> after portal vein embolization: An accurate predictor of future liver remnant hypertrophy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mohkam, Kayvan; Rode, Agnès; Darnis, Benjamin; Manichon, Anne-Frédérique; Boussel, Loïc; Ducerf, Christian; Merle, Philippe; Lesurtel, Mickaël; Mabrut, Jean-Yves</p> <p>2018-05-09</p> <p>The impact of portal hemodynamic variations after portal vein embolization on liver regeneration remains unknown. We studied the correlation between the parameters of hepatic venous <span class="hlt">pressure</span> measured before and after portal vein embolization and future hypertrophy of the liver remnant after portal vein embolization. Between 2014 and 2017, we reviewed patients who were eligible for major hepatectomy and who had portal vein embolization. Patients had undergone simultaneous measurement of portal venous <span class="hlt">pressure</span> and hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> before and after portal vein embolization by direct puncture of portal vein and inferior vena cava. We assessed these parameters to predict future liver remnant hypertrophy. Twenty-six patients were included. After portal vein embolization, median portal venous <span class="hlt">pressure</span> (range) increased from 15 (9-24) to 19 (10-27) mm Hg and hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> increased from 5 (0-12) to 8 (0-14) mm Hg. Median future liver remnant volume (range) was 513 (299-933) mL before portal vein embolization versus 724 (499-1279) mL 3 weeks after portal vein embolization, representing a 35% (7.4-83.6) median hypertrophy. Post-portal vein embolization hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> was the most accurate parameter to predict failure of future liver remnant to reach a 30% hypertrophy (c-statistic: 0.882 [95% CI: 0.727-1.000], P < 0.001). A cut-off value of post-portal vein embolization hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> of 8 mm Hg showed a sensitivity of 91% (95% CI: 57%-99%), specificity of 80% (95% CI: 52%-96%), positive predictive value of 77% (95% CI: 46%-95%) and negative predictive value of 92.3% (95% CI: 64.0%-99.8%). On multivariate analysis, post-portal vein embolization hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> and previous chemotherapy were identified as predictors of impaired future liver remnant hypertrophy. Post-portal vein embolization hepatic venous <span class="hlt">pressure</span> <span class="hlt">gradient</span> is a simple and reproducible tool which accurately predicts future</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol5/pdf/CFR-2014-title46-vol5-sec154-405.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol5/pdf/CFR-2014-title46-vol5-sec154-405.pdf"><span>46 CFR 154.405 - Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank.</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>... 46 Shipping 5 2014-10-01 2014-10-01 false Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank. 154.405 Section 154.405 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems §...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol5/pdf/CFR-2013-title46-vol5-sec154-405.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol5/pdf/CFR-2013-title46-vol5-sec154-405.pdf"><span>46 CFR 154.405 - Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank.</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>... 46 Shipping 5 2013-10-01 2013-10-01 false Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank. 154.405 Section 154.405 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems §...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol5/pdf/CFR-2012-title46-vol5-sec154-405.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol5/pdf/CFR-2012-title46-vol5-sec154-405.pdf"><span>46 CFR 154.405 - Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank.</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>... 46 Shipping 5 2012-10-01 2012-10-01 false Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank. 154.405 Section 154.405 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems §...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol5/pdf/CFR-2010-title46-vol5-sec154-405.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol5/pdf/CFR-2010-title46-vol5-sec154-405.pdf"><span>46 CFR 154.405 - Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank.</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>... 46 Shipping 5 2010-10-01 2010-10-01 false Design <span class="hlt">vapor</span> <span class="hlt">pressure</span> (Po) of a cargo tank. 154.405 Section 154.405 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems §...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29346725','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29346725"><span>Rapid Chemical <span class="hlt">Vapor</span> Infiltration of Silicon Carbide Minicomposites at Atmospheric <span class="hlt">Pressure</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Petroski, Kenneth; Poges, Shannon; Monteleone, Chris; Grady, Joseph; Bhatt, Ram; Suib, Steven L</p> <p>2018-02-07</p> <p>The chemical <span class="hlt">vapor</span> infiltration technique is one of the most popular for the fabrication of the matrix portion of a ceramic matrix composite. This work focuses on tailoring an atmospheric <span class="hlt">pressure</span> deposition of silicon carbide onto carbon fiber tows using the methyltrichlorosilane (CH 3 SiCl 3 ) and H 2 deposition system at atmospheric <span class="hlt">pressure</span> to create minicomposites faster than low <span class="hlt">pressure</span> systems. Adjustment of the flow rate of H 2 bubbled through CH 3 SiCl 3 will improve the uniformity of the deposition as well as infiltrate the substrate more completely as the flow rate is decreased. Low <span class="hlt">pressure</span> depositions conducted at 50 Torr deposit SiC at a rate of approximately 200 nm*h -1 , while the atmospheric <span class="hlt">pressure</span> system presented has a deposition rate ranging from 750 nm*h -1 to 3.88 μm*h -1 . The minicomposites fabricated in this study had approximate total porosities of 3 and 6% for 10 and 25 SCCM infiltrations, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.H22A..07M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.H22A..07M"><span>Transport of Carbon Tetrachloride in a Fractured Vadose Zone due to Atmospheric <span class="hlt">Pressure</span> Fluctuations, Diffusion, and <span class="hlt">Vapor</span> Density</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCray, J. E.; Downs, W.; Falta, R. W.; Housley, T.</p> <p>2005-12-01</p> <p>DNAPL sources of carbon tetrachloride (CT) <span class="hlt">vapors</span> are of interest at the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering and Environmental Laboratory (INEEL). The site is underlain by thick fractured basalt that includes sedimentary interbeds, each are a few meters thick. Daily atmospheric <span class="hlt">pressure</span> fluctuations serve as driving forces for CT <span class="hlt">vapor</span> transport in the subsurface. Other important transport processes for <span class="hlt">vapor</span> movement include gas-phase diffusion and density-driven transport. The objective of this research is to investigate the influence and relative importance of these processes on gaseous transport of CT. Gas <span class="hlt">pressure</span> and <span class="hlt">vapor</span> concentration measurements were conducted at various depths in two wells. A numerical multiphase flow model (TOUGH2), calibrated to field <span class="hlt">pressure</span> data, is used to conduct sensitivity analyses to elucidate the importance of the different transport mechanisms. Results show that the basalt is highly permeable to vertical air flow. The <span class="hlt">pressure</span> dampening occurs mainly in the sedimentary interbeds. Model-calibrated permeability values for the interbeds are similar to those obtained in a study by the U.S. Geological Survey for shallow sediments, and an order of magnitude higher than column-scale values obtained by previous studies conducted by INEEL scientists. The transport simulations indicate that considering the effect of barometric <span class="hlt">pressure</span> changes is critical to simulating transport of pollutants in the vadose zone above the DNAPL source. Predicted concentrations can be orders of magnitude smaller than actual concentrations if the effect is not considered. Below the DNAPL <span class="hlt">vapor</span> source, accounting for density and diffusion alone would yield acceptable results provided that a 20% error in concentrations are acceptable, and that simulating concentrations trends (and not actual concentrations) is the primary goal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960022382','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960022382"><span>Methods of Measuring <span class="hlt">Vapor</span> <span class="hlt">Pressures</span> of Lubricants With Their Additives Using TGA and/or Microbalances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scialdone, John J.; Miller, Michael K.; Montoya, Alex F.</p> <p>1996-01-01</p> <p>The life of a space system may be critically dependent on the lubrication of some of its moving parts. The <span class="hlt">vapor</span> <span class="hlt">pressure</span>, the quantity of the available lubricant, the temperature and the exhaust venting conductance passage are important considerations in the selection and application of a lubricant. In addition, the oil additives employed to provide certain properties of low friction, surface tension, antioxidant and load bearing characteristics, are also very important and need to be known with regard to their amounts and <span class="hlt">vapor</span> <span class="hlt">pressures</span>. This paper reports on the measurements and analyses carried out to obtain those parameters for two often employed lubricants, the Apiezon(TM)-C and the Krytox(TM) AB. The measurements were made employing an electronic microbalance and a thermogravimetric analyzer (TGA) modified to operate in a vacuum. The results have been compared to other data on these oils when available. The identification of the mass fractions of the additives in the oil and their <span class="hlt">vapor</span> <span class="hlt">pressures</span> as a function of the temperature were carried out. These may be used to estimate the lubricant life given its quantity and the system vent exhaust conductance. It was found that the Apiezon(TM)-C has three main components with different rates of evaporation while the Krytox(TM) did not indicate any measurable additive.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDM28006G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDM28006G"><span>DNS of a non-equilibrium adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> turbulent boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gungor, Taygun R.; Gungor, Ayse G.; Maciel, Yvan; Simens, Mark P.</p> <p>2017-11-01</p> <p>A new direct numerical simulation (DNS) dataset of a non-equilibrium adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> (APG) turbulent boundary layer (TBL) that evolves from a zero-<span class="hlt">pressure-gradient</span> (ZPG) TBL to a TBL which is very close to separation at Reθ is around 8200 is presented. There are two simulations running together in the DNS computational setup. The APG TBL spans Reθ = 1476 - 8276 . Mean velocity results do not satisfy the log law as the defect in the velocity increases. The production and the Reynolds stress peak are observed around y /δ* = 1 after the flow is evolved up to a certain point. The new dataset is compared with other datasets in terms of mean values, Reynolds stresses and turbulent kinetic energy budgets and using this comparison scaling study is performed. Funded by in part by ITU-AYP and NSERC of Canada.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5228218','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5228218"><span>Impacts of Changes of Indoor Air <span class="hlt">Pressure</span> and Air Exchange Rate in <span class="hlt">Vapor</span> Intrusion Scenarios</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shen, Rui; Suuberg, Eric M.</p> <p>2016-01-01</p> <p>There has, in recent years, been increasing interest in understanding the transport processes of relevance in <span class="hlt">vapor</span> intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant <span class="hlt">vapor</span> concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in <span class="hlt">vapor</span> intrusion situations, including the indoor air <span class="hlt">pressure</span> and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air <span class="hlt">pressure</span> and air exchange rate are seen to contribute to significant variations in indoor air contaminant <span class="hlt">vapor</span> concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures. PMID:28090133</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28090133','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28090133"><span>Impacts of Changes of Indoor Air <span class="hlt">Pressure</span> and Air Exchange Rate in <span class="hlt">Vapor</span> Intrusion Scenarios.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shen, Rui; Suuberg, Eric M</p> <p>2016-02-01</p> <p>There has, in recent years, been increasing interest in understanding the transport processes of relevance in <span class="hlt">vapor</span> intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant <span class="hlt">vapor</span> concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in <span class="hlt">vapor</span> intrusion situations, including the indoor air <span class="hlt">pressure</span> and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air <span class="hlt">pressure</span> and air exchange rate are seen to contribute to significant variations in indoor air contaminant <span class="hlt">vapor</span> concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940007697&hterms=geothermal&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgeothermal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940007697&hterms=geothermal&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgeothermal"><span>The role of the geothermal <span class="hlt">gradient</span> in the emplacement and replenishment of ground ice on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clifford, Stephen M.</p> <p>1993-01-01</p> <p>Knowledge of the mechanisms by which ground ice is emplaced, removed, and potentially replenished, are critical to understanding the climatic and hydrologic behavior of water on Mars, as well as the morphologic evolution of its surface. Because of the strong temperature dependence of the saturated <span class="hlt">vapor</span> <span class="hlt">pressure</span> of H2O, the atmospheric emplacement or replenishment of ground ice is prohibited below the depth at which crustal temperatures begin to monotonically increase due to geothermal heating. In contrast, the emplacement and replenishment of ground ice from reservoirs of H2O residing deep within the crust can occur by at least three different thermally-driven processes, involving all three phases of water. In this regard, Clifford has discussed how the presence of a geothermal <span class="hlt">gradient</span> as small as 15 K/km can give rise to a corresponding <span class="hlt">vapor</span> <span class="hlt">pressure</span> <span class="hlt">gradient</span> sufficient to drive the vertical transport of 1 km of water from a reservoir of ground water at depth to the base of the cryosphere every 10(exp 6) - 10(exp 7) years. This abstract expands on this earlier treatment by considering the influence of thermal <span class="hlt">gradients</span> on the transport of H2O at temperatures below the freezing point.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990104326&hterms=partial+pressure+oxygen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpartial%2Bpressure%2Boxygen','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990104326&hterms=partial+pressure+oxygen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpartial%2Bpressure%2Boxygen"><span>Mass Spectrometric Identification of Si-O-H(g) Species from the Reaction of Silica with Water <span class="hlt">Vapor</span> at Atmospheric <span class="hlt">Pressure</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Opila, Elizabeth J.; Fox, Dennis S.; Jacobson, Nathan S.</p> <p>1997-01-01</p> <p>A high-<span class="hlt">pressure</span> sampling mass spectrometer was used to detect the volatile species formed from SiO2 at temperatures between 1200C and 1400C in a flowing water <span class="hlt">vapor</span>/oxygen gas mixture at 1 bar total <span class="hlt">pressure</span>. The primary <span class="hlt">vapor</span> species identified was Si(OH)4. The fragment ion Si(OH)3+,' was observed in quantities 3 to 5 times larger than the parent ion Si(OH)4+. The Si(OH)3+ intensity was found to have a small temperature dependence and to increase with the water <span class="hlt">vapor</span> partial <span class="hlt">pressure</span> as expected. In addition, SiO(OH)+ believed to be a fragment of SiO(OH)2, was observed. These mass spectral results were compared to the behavior of silicon halides.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090013712','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090013712"><span>Evaluation of <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.</p> <p>2008-01-01</p> <p>Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible <span class="hlt">vapor</span> <span class="hlt">pressures</span> under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the <span class="hlt">vapor</span> <span class="hlt">pressure</span> and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present <span class="hlt">vapor</span> <span class="hlt">pressure</span> measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000054269&hterms=water+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwater%2Bchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000054269&hterms=water+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwater%2Bchange"><span>Water <span class="hlt">Vapor</span> Feedbacks to Climate Change</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rind, David</p> <p>1999-01-01</p> <p>The response of water <span class="hlt">vapor</span> to climate change is investigated through a series of model studies with varying latitudinal temperature <span class="hlt">gradients</span>, mean temperatures, and ultimately, actual climate change configurations. Questions to be addressed include: what role does varying convection have in water <span class="hlt">vapor</span> feedback; do Hadley Circulation differences result in differences in water <span class="hlt">vapor</span> in the upper troposphere; and, does increased eddy energy result in greater eddy vertical transport of water <span class="hlt">vapor</span> in varying climate regimes?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713547P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713547P"><span>The Phase Rule in a System Subject to a <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Podladchikov, Yuri; Connolly, James; Powell, Roger; Aardvark, Alberto</p> <p>2015-04-01</p> <p>It can be shown by diligent application of Lagrange's method of undetermined multipliers that the phase rule in a system subject to a <span class="hlt">pressure</span> <span class="hlt">gradient</span> is: � + 赑 ≥ ρ. We explore the consequence of this important relationship for natural systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750020309','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750020309"><span><span class="hlt">Pressure</span> <span class="hlt">gradient</span> effects on heat transfer to reusable surface insulation tile-array gaps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Throckmorton, D. A.</p> <p>1975-01-01</p> <p>An experimental investigation was performed to determine the effect of <span class="hlt">pressure</span> <span class="hlt">gradient</span> on the heat transfer within space shuttle reusable surface insulation (RSI) tile-array gaps under thick, turbulent boundary-layer conditions. Heat-transfer and <span class="hlt">pressure</span> measurements were obtained on a curved array of full-scale simulated RSI tiles in a tunnel-wall boundary layer at a nominal free-stream Mach number and free-stream Reynolds numbers. Transverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> of varying degree were induced over the model surface by rotating the curved array with respect to the flow. Definition of the tunnel-wall boundary-layer flow was obtained by measurement of boundary-layer pitot <span class="hlt">pressure</span> profiles, wall <span class="hlt">pressure</span>, and heat transfer. Flat-plate heat-transfer data were correlated and a method was derived for prediction of heat transfer to a smooth curved surface in the highly three-dimensional tunnel-wall boundary-layer flow. <span class="hlt">Pressure</span> on the floor of the RSI tile-array gap followed the trends of the external surface <span class="hlt">pressure</span>. Heat transfer to the surface immediately downstream of a transverse gap is higher than that for a smooth surface at the same location. Heating to the wall of a transverse gap, and immediately downstream of it, at its intersection with a longitudinal gap is significantly greater than that for the simple transverse gap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol5/pdf/CFR-2013-title46-vol5-sec154-1836.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title46-vol5/pdf/CFR-2013-title46-vol5-sec154-1836.pdf"><span>46 CFR 154.1836 - <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature control.</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>... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature... cargo <span class="hlt">pressure</span> and temperature control system under §§ 154.701 through 154.709 is operating and that...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol5/pdf/CFR-2014-title46-vol5-sec154-1836.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title46-vol5/pdf/CFR-2014-title46-vol5-sec154-1836.pdf"><span>46 CFR 154.1836 - <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature control.</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>... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature... cargo <span class="hlt">pressure</span> and temperature control system under §§ 154.701 through 154.709 is operating and that...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol5/pdf/CFR-2012-title46-vol5-sec154-1836.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol5/pdf/CFR-2012-title46-vol5-sec154-1836.pdf"><span>46 CFR 154.1836 - <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature control.</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>... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature... cargo <span class="hlt">pressure</span> and temperature control system under §§ 154.701 through 154.709 is operating and that...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol5/pdf/CFR-2010-title46-vol5-sec154-1836.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol5/pdf/CFR-2010-title46-vol5-sec154-1836.pdf"><span>46 CFR 154.1836 - <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature control.</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>... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature... cargo <span class="hlt">pressure</span> and temperature control system under §§ 154.701 through 154.709 is operating and that...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol5/pdf/CFR-2011-title46-vol5-sec154-1836.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol5/pdf/CFR-2011-title46-vol5-sec154-1836.pdf"><span>46 CFR 154.1836 - <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature control.</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>... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... LIQUEFIED GASES Operations § 154.1836 <span class="hlt">Vapor</span> venting as a means of cargo tank <span class="hlt">pressure</span> and temperature... cargo <span class="hlt">pressure</span> and temperature control system under §§ 154.701 through 154.709 is operating and that...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930040417&hterms=curvature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dcurvature','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930040417&hterms=curvature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dcurvature"><span>Turbulent boundary layers subjected to multiple curvatures and <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bandyopadhyay, Promode R.; Ahmed, Anwar</p> <p>1993-01-01</p> <p>The effects of abruptly applied cycles of curvatures and <span class="hlt">pressure</span> <span class="hlt">gradients</span> on turbulent boundary layers are examined experimentally. Two two-dimensional curved test surfaces are considered: one has a sequence of concave and convex longitudinal surface curvatures and the other has a sequence of convex and concave curvatures. The choice of the curvature sequences were motivated by a desire to study the asymmetric response of turbulent boundary layers to convex and concave curvatures. The relaxation of a boundary layer from the effects of these two opposite sequences has been compared. The effect of the accompaying sequences of <span class="hlt">pressure</span> <span class="hlt">gradient</span> has also been examined but the effect of curvature dominates. The growth of internal layers at the curvature junctions have been studied. Measurements of the Gortler and corner vortex systems have been made. The boundary layer recovering from the sequence of concave to convex curvature has a sustained lower skin friction level than in that recovering from the sequence of convex to concave curvature. The amplification and suppression of turbulence due to the curvature sequences have also been studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940028441','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940028441"><span>Modification of the MML turbulence model for adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> flows. M.S. Thesis - Akron Univ., 1993</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Conley, Julianne M.</p> <p>1994-01-01</p> <p>Computational fluid dynamics is being used increasingly to predict flows for aerospace propulsion applications, yet there is still a need for an easy to use, computationally inexpensive turbulence model capable of accurately predicting a wide range of turbulent flows. The Baldwin-Lomax model is the most widely used algebraic model, even though it has known difficulties calculating flows with strong adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> and large regions of separation. The modified mixing length model (MML) was developed specifically to handle the separation which occurs on airfoils and has given significantly better results than the Baldwin-Lomax model. The success of these calculations warrants further evaluation and development of MML. The objective of this work was to evaluate the performance of MML for zero and adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> flows, and modify it as needed. The Proteus Navier-Stokes code was used for this study and all results were compared with experimental data and with calculations made using the Baldwin-Lomax algebraic model, which is currently available in Proteus. The MML model was first evaluated for zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> flow over a flat plate, then modified to produce the proper boundary layer growth. Additional modifications, based on experimental data for three adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> flows, were also implemented. The adapted model, called MMLPG (modified mixing length model for <span class="hlt">pressure</span> <span class="hlt">gradient</span> flows), was then evaluated for a typical propulsion flow problem, flow through a transonic diffuser. Three cases were examined: flow with no shock, a weak shock and a strong shock. The results of these calculations indicate that the objectives of this study have been met. Overall, MMLPG is capable of accurately predicting the adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> flows examined in this study, giving generally better agreement with experimental data than the Baldwin-Lomax model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JCoPh.353..377A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JCoPh.353..377A"><span><span class="hlt">Gradient</span> augmented level set method for phase change simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anumolu, Lakshman; Trujillo, Mario F.</p> <p>2018-01-01</p> <p>A numerical method for the simulation of two-phase flow with phase change based on the <span class="hlt">Gradient</span>-Augmented-Level-set (GALS) strategy is presented. Sharp capturing of the <span class="hlt">vaporization</span> process is enabled by: i) identification of the <span class="hlt">vapor</span>-liquid interface, Γ (t), at the subgrid level, ii) discontinuous treatment of thermal physical properties (except for μ), and iii) enforcement of mass, momentum, and energy jump conditions, where the <span class="hlt">gradients</span> of the dependent variables are obtained at Γ (t) and are consistent with their analytical expression, i.e. no local averaging is applied. Treatment of the jump in velocity and <span class="hlt">pressure</span> at Γ (t) is achieved using the Ghost Fluid Method. The solution of the energy equation employs the sub-grid knowledge of Γ (t) to discretize the temperature Laplacian using second-order one-sided differences, i.e. the numerical stencil completely resides within each respective phase. To carefully evaluate the benefits or disadvantages of the GALS approach, the standard level set method is implemented and compared against the GALS predictions. The results show the expected trend that interface identification and transport are predicted noticeably better with GALS over the standard level set. This benefit carries over to the prediction of the Laplacian and temperature <span class="hlt">gradients</span> in the neighborhood of the interface, which are directly linked to the calculation of the <span class="hlt">vaporization</span> rate. However, when combining the calculation of interface transport and reinitialization with two-phase momentum and energy, the benefits of GALS are to some extent neutralized, and the causes for this behavior are identified and analyzed. Overall the additional computational costs associated with GALS are almost the same as those using the standard level set technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27350150','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27350150"><span>Inhaled Beta Agonist Bronchodilator Does Not Affect Trans-diaphragmatic <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> but Decreases Lower Esophageal Sphincter Retention <span class="hlt">Pressure</span> in Patients with Chronic Obstructive Pulmonary Disease (COPD) and Gastroesophageal Reflux Disease (GERD).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Del Grande, Leonardo M; Herbella, Fernando A M; Bigatao, Amilcar M; Jardim, Jose R; Patti, Marco G</p> <p>2016-10-01</p> <p>Chronic obstructive pulmonary disease (COPD) patients have a high incidence of gastroesophageal reflux disease (GERD) whose pathophysiology seems to be linked to an increased trans-diaphragmatic <span class="hlt">pressure</span> <span class="hlt">gradient</span> and not to a defective esophagogastric barrier. Inhaled beta agonist bronchodilators are a common therapy used by patients with COPD. This drug knowingly not only leads to a decrease in the lower esophageal sphincter (LES) resting <span class="hlt">pressure</span>, favoring GERD, but also may improve ventilatory parameters, therefore preventing GERD. This study aims to evaluate the effect of inhaled beta agonist bronchodilators on the trans-diaphragmatic <span class="hlt">pressure</span> <span class="hlt">gradient</span> and the esophagogastric barrier. We studied 21 patients (mean age 67 years, 57 % males) with COPD and GERD. All patients underwent high-resolution manometry and esophageal pH monitoring. Abdominal and thoracic <span class="hlt">pressure</span>, trans-diaphragmatic <span class="hlt">pressure</span> <span class="hlt">gradient</span> (abdominal-thoracic <span class="hlt">pressure</span>), and the LES retention <span class="hlt">pressure</span> (LES basal <span class="hlt">pressure</span>-transdiaphragmatic <span class="hlt">gradient</span>) were measured before and 5 min after inhaling beta agonist bronchodilators. The administration of inhaled beta agonist bronchodilators leads to the following: (a) a simultaneous increase in abdominal and thoracic <span class="hlt">pressure</span> not affecting the trans-diaphragmatic <span class="hlt">pressure</span> <span class="hlt">gradient</span> and (b) a decrease in the LES resting <span class="hlt">pressure</span> with a reduction of the LES retention <span class="hlt">pressure</span>. In conclusion, inhaled beta agonist bronchodilators not only increase the thoracic <span class="hlt">pressure</span> but also lead to an increased abdominal <span class="hlt">pressure</span> favoring GERD by affecting the esophagogastric barrier.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040141463&hterms=left&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dleft','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040141463&hterms=left&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dleft"><span>Doppler echo evaluation of pulmonary venous-left atrial <span class="hlt">pressure</span> <span class="hlt">gradients</span>: human and numerical model studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Firstenberg, M. S.; Greenberg, N. L.; Smedira, N. G.; Prior, D. L.; Scalia, G. M.; Thomas, J. D.; Garcia, M. J.</p> <p>2000-01-01</p> <p>The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a <span class="hlt">pressure</span> <span class="hlt">gradient</span> and is commonly used in clinical echocardiography to determine <span class="hlt">pressure</span> differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity pulmonary venous and left atrial <span class="hlt">pressure</span> measurements and pulmonary venous pulsed Doppler echocardiography performed. Convective <span class="hlt">gradients</span> for the systolic (S), diastolic (D), and atrial reversal (AR) phases of pulmonary venous flow were determined using the simplified Bernoulli equation and correlated with measured actual <span class="hlt">pressure</span> differences. A linear relationship was observed between the convective (y) and actual (x) <span class="hlt">pressure</span> differences for the S (y = 0.23x + 0.0074, r = 0.82) and D (y = 0.22x + 0.092, r = 0.81) waves, but not for the AR wave (y = 0. 030x + 0.13, r = 0.10). Numerical modeling resulted in similar slopes for the S (y = 0.200x - 0.127, r = 0.97), D (y = 0.247x - 0. 354, r = 0.99), and AR (y = 0.087x - 0.083, r = 0.96) waves. Consistent with numerical modeling, the convective term strongly correlates with but significantly underestimates actual <span class="hlt">gradient</span> because of large inertial forces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10924058','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10924058"><span>Doppler echo evaluation of pulmonary venous-left atrial <span class="hlt">pressure</span> <span class="hlt">gradients</span>: human and numerical model studies.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Firstenberg, M S; Greenberg, N L; Smedira, N G; Prior, D L; Scalia, G M; Thomas, J D; Garcia, M J</p> <p>2000-08-01</p> <p>The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a <span class="hlt">pressure</span> <span class="hlt">gradient</span> and is commonly used in clinical echocardiography to determine <span class="hlt">pressure</span> differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity pulmonary venous and left atrial <span class="hlt">pressure</span> measurements and pulmonary venous pulsed Doppler echocardiography performed. Convective <span class="hlt">gradients</span> for the systolic (S), diastolic (D), and atrial reversal (AR) phases of pulmonary venous flow were determined using the simplified Bernoulli equation and correlated with measured actual <span class="hlt">pressure</span> differences. A linear relationship was observed between the convective (y) and actual (x) <span class="hlt">pressure</span> differences for the S (y = 0.23x + 0.0074, r = 0.82) and D (y = 0.22x + 0.092, r = 0.81) waves, but not for the AR wave (y = 0. 030x + 0.13, r = 0.10). Numerical modeling resulted in similar slopes for the S (y = 0.200x - 0.127, r = 0.97), D (y = 0.247x - 0. 354, r = 0.99), and AR (y = 0.087x - 0.083, r = 0.96) waves. Consistent with numerical modeling, the convective term strongly correlates with but significantly underestimates actual <span class="hlt">gradient</span> because of large inertial forces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MsT.........27L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MsT.........27L"><span>Thermodynamic Modeling and Mechanical Design of a Liquid Nitrogen <span class="hlt">Vaporization</span> and <span class="hlt">Pressure</span> Building Device</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leege, Brian J.</p> <p></p> <p>The design of a liquid nitrogen <span class="hlt">vaporization</span> and <span class="hlt">pressure</span> building device that has zero product waste while recovering some of its stored energy is of interest for the cost reduction of nitrogen for use in industrial processes. Current devices may waste up to 30% of the gaseous nitrogen product by venting it to atmosphere. Furthermore, no attempt is made to recover the thermal energy available in the coldness of the cryogen. A seven step cycle with changing volumes and ambient heat addition is proposed, eliminating all product waste and providing the means of energy recovery from the nitrogen. This thesis discusses the new thermodynamic cycle and modeling as well as the mechanical design and testing of a prototype device. The prototype was able to achieve liquid nitrogen <span class="hlt">vaporization</span> and <span class="hlt">pressurization</span> up to 1000 psi, while full cycle validation is ongoing with promising initial results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDL26012K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDL26012K"><span>Characterization of Rare Reverse Flow Events in Adverse <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> Turbulent Boundary Layers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaehler, Christian J.; Bross, Matthew; Fuchs, Thomas</p> <p>2017-11-01</p> <p>Time-resolved tomographic flow fields measured in the viscous sublayer region of a turbulent boundary layer subjected to an adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> (APG) are examined with the aim to resolve and characterize reverse flow events at Reτ = 5000. The fields were measured using a novel high resolution tomographic particle tracking technique. It is shown that this technique is able to fully resolve mean and time dependent features of the complex three-dimensional flow with high accuracy down to very near-wall distances ( 10 μm). From time resolved Lagrangian particle trajectories, statistical information as well as instantaneous topological features of near-wall flow events are deduced. Similar to the zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> case (ZPG), it was found that individual events with reverse flow components still occur relatively rarely under the action of the <span class="hlt">pressure</span> <span class="hlt">gradient</span> investigated here. However, reverse flow events comprised of many individual events, are shown to appear in relatively organized groupings in both spanwise and streamise directions. Furthermore, instantaneous measurements of reverse flow events show that these events are associated with the motion of low-momentum streaks in the near-wall region. This work is supported by the Priority Programme SPP 1881 Turbulent Superstructures and the individual project Grant KA1808/8-2 of the Deutsche Forschungsgemeinschaft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000890','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000890"><span>CVB: the Constrained <span class="hlt">Vapor</span> Bubble Capillary Experiment on the International Space Station MARANGONI FLOW REGION</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wayner, Peter C., Jr.; Kundan, Akshay; Plawsky, Joel</p> <p>2014-01-01</p> <p>The Constrained <span class="hlt">Vapor</span> Bubble (CVB) is a wickless, grooved heat pipe and we report on a full- scale fluids experiment flown on the International Space Station (ISS). The CVB system consists of a relatively simple setup a quartz cuvette with sharp corners partially filled with either pentane or an ideal mixture of pentane and isohexane as the working fluids. Along with temperature and <span class="hlt">pressure</span> measurements, the two-dimensional thickness profile of the menisci formed at the corners of the quartz cuvette was determined using the Light Microscopy Module (LMM). Even with the large, millimeter dimensions of the CVB, interfacial forces dominate in these exceedingly small Bond Number systems. The experiments were carried out at various power inputs. Although conceptually simple, the transport processes were found to be very complex with many different regions. At the heated end of the CVB, due to a high temperature <span class="hlt">gradient</span>, we observed Marangoni flow at some power inputs. This region from the heated end to the central drop region is defined as a Marangoni dominated region. We present a simple analysis based on interfacial phenomena using only measurements from the ISS experiments that lead to a predictive equation for the thickness of the film near the heated end of the CVB. The average <span class="hlt">pressure</span> <span class="hlt">gradient</span> for flow in the film is assumed due to the measured capillary <span class="hlt">pressure</span> at the two ends of the liquid film and that the <span class="hlt">pressure</span> stress <span class="hlt">gradient</span> due to cohesion self adjusts to a constant value over a distance L. The boundary conditions are the no slip condition at the wall interface and an interfacial shear stress at the liquid- <span class="hlt">vapor</span> interface due to the Marangoni stress, which is due to the high temperature <span class="hlt">gradient</span>. Although the heated end is extremely complex, since it includes three- dimensional variations in radiation, conduction, evaporation, condensation, fluid flow and interfacial forces, we find that using the above simplifying assumptions, a simple successful</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=POLYMER&pg=2&id=EJ1084250','ERIC'); return false;" href="https://eric.ed.gov/?q=POLYMER&pg=2&id=EJ1084250"><span>Molar Mass and Second Virial Coefficient of Polyethylene Glycol by <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> Osmometry</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Schwinefus, Jeffrey J.; Checkal, Caleb; Saksa, Brian; Baka, Nadia; Modi, Kalpit; Rivera, Carlos</p> <p>2015-01-01</p> <p>In this laboratory experiment, students determine the number-average molar masses and second virial coefficients of polyethylene glycol (PEG) polymers ranging in molar mass from 200 to 1500 g mol[superscript -1] using <span class="hlt">vapor</span> <span class="hlt">pressure</span> osmometry (VPO). Students assess VPO in relation to accurate molar mass calculations of PEG polymers. Additionally,…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OcMod.116....1E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OcMod.116....1E"><span>High-order accurate finite-volume formulations for the <span class="hlt">pressure</span> <span class="hlt">gradient</span> force in layered ocean models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Engwirda, Darren; Kelley, Maxwell; Marshall, John</p> <p>2017-08-01</p> <p>Discretisation of the horizontal <span class="hlt">pressure</span> <span class="hlt">gradient</span> force in layered ocean models is a challenging task, with non-trivial interactions between the thermodynamics of the fluid and the geometry of the layers often leading to numerical difficulties. We present two new finite-volume schemes for the <span class="hlt">pressure</span> <span class="hlt">gradient</span> operator designed to address these issues. In each case, the horizontal acceleration is computed as an integration of the contact <span class="hlt">pressure</span> force that acts along the perimeter of an associated momentum control-volume. A pair of new schemes are developed by exploring different control-volume geometries. Non-linearities in the underlying equation-of-state definitions and thermodynamic profiles are treated using a high-order accurate numerical integration framework, designed to preserve hydrostatic balance in a non-linear manner. Numerical experiments show that the new methods achieve high levels of consistency, maintaining hydrostatic and thermobaric equilibrium in the presence of strongly-sloping layer geometries, non-linear equations-of-state and non-uniform vertical stratification profiles. These results suggest that the new <span class="hlt">pressure</span> <span class="hlt">gradient</span> formulations may be appropriate for general circulation models that employ hybrid vertical coordinates and/or terrain-following representations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H11N..07Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H11N..07Z"><span>The hysteretic evapotranspiration - <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit relation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Q.; Manzoni, S.; Katul, G. G.; Porporato, A. M.; Yang, D.</p> <p>2013-12-01</p> <p>Diurnal hysteresis between evapotranspiration (ET) and <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit (VPD) was reported in many ecosystems but justification for its onset and magnitude remain incomplete with biotic and abiotic factors invoked as possible explanations. To place these explanations within a mathematical framework, ';rate-dependent' hysteresis originating from a phase angle difference between periodic input and output time series is first considered. Lysimeter evaporation (E) measurements from wet bare soils and model calculations using the Penman equation demonstrate that the E-VPD hysteresis emerges without any biotic effects due to a phase angle difference (or time lag) between net radiation the main driver of E, and VPD. Modulations originating from biotic effects on the ET-VPD hysteresis were then considered. The phase angle difference representation earlier employed was mathematically transformed into a storage problem and applied to the soil-plant system. The transformed system shows that soil moisture storage within the root zone can produce an ET-VPD hysteresis prototypical of those generated by phase-angle differences. To explore the interplay between all the lags in the soil-plant-atmosphere system and phase angle differences among forcing and response variables, a detailed soil-plant-atmosphere continuum (SPAC) model was developed and applied to a grassland ecosystem. The results of the SPAC model suggest that the hysteresis magnitude depends on the radiation-VPD lag. The soil moisture dry-down simulations also suggest that modeled root water potential and leaf water potential are both better indicators of the hysteresis magnitude than soil moisture, suggesting that plant water status is the main factor regulating the hysteretic relation between ET and VPD. Hence, the genesis and magnitude of the ET-VPD hysteresis are controlled directly by both biotic factors and abiotic factors such as time lag between radiation and VPD originating from boundary layer processes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27986288','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27986288"><span>A practical approach for predicting retention time shifts due to <span class="hlt">pressure</span> and temperature <span class="hlt">gradients</span> in ultra-high-<span class="hlt">pressure</span> liquid chromatography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Åsberg, Dennis; Chutkowski, Marcin; Leśko, Marek; Samuelsson, Jörgen; Kaczmarski, Krzysztof; Fornstedt, Torgny</p> <p>2017-01-06</p> <p>Large <span class="hlt">pressure</span> <span class="hlt">gradients</span> are generated in ultra-high-<span class="hlt">pressure</span> liquid chromatography (UHPLC) using sub-2μm particles causing significant temperature <span class="hlt">gradients</span> over the column due to viscous heating. These <span class="hlt">pressure</span> and temperature <span class="hlt">gradients</span> affect retention and ultimately result in important selectivity shifts. In this study, we developed an approach for predicting the retention time shifts due to these <span class="hlt">gradients</span>. The approach is presented as a step-by-step procedure and it is based on empirical linear relationships describing how retention varies as a function of temperature and <span class="hlt">pressure</span> and how the average column temperature increases with the flow rate. It requires only four experiments on standard equipment, is based on straightforward calculations, and is therefore easy to use in method development. The approach was rigorously validated against experimental data obtained with a quality control method for the active pharmaceutical ingredient omeprazole. The accuracy of retention time predictions was very good with relative errors always less than 1% and in many cases around 0.5% (n=32). Selectivity shifts observed between omeprazole and the related impurities when changing the flow rate could also be accurately predicted resulting in good estimates of the resolution between critical peak pairs. The approximations which the presented approach are based on were all justified. The retention factor as a function of <span class="hlt">pressure</span> and temperature was studied in an experimental design while the temperature distribution in the column was obtained by solving the fundamental heat and mass balance equations for the different experimental conditions. We strongly believe that this approach is sufficiently accurate and experimentally feasible for this separation to be a valuable tool when developing a UHPLC method. After further validation with other separation systems, it could become a useful approach in UHPLC method development, especially in the pharmaceutical industry where</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930092289','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930092289"><span>Similar solutions for the compressible laminar boundary layer with heat transfer and <span class="hlt">pressure</span> <span class="hlt">gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cohen, Clarence B; Reshotko, Eli</p> <p>1956-01-01</p> <p>Stewartson's transformation is applied to the laminar compressible boundary-layer equations and the requirement of similarity is introduced, resulting in a set of ordinary nonlinear differential equations previously quoted by Stewartson, but unsolved. The requirements of the system are Prandtl number of 1.0, linear viscosity-temperature relation across the boundary layer, an isothermal surface, and the particular distributions of free-stream velocity consistent with similar solutions. This system admits axial <span class="hlt">pressure</span> <span class="hlt">gradients</span> of arbitrary magnitude, heat flux normal to the surface, and arbitrary Mach numbers. The system of differential equations is transformed to integral system, with the velocity ratio as the independent variable. For this system, solutions are found by digital computation for <span class="hlt">pressure</span> <span class="hlt">gradients</span> varying from that causing separation to the infinitely favorable <span class="hlt">gradient</span> and for wall temperatures from absolute zero to twice the free-stream stagnation temperature. Some solutions for separated flows are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010059950','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010059950"><span>Water <span class="hlt">Vapor</span> Effects on Silica-Forming Ceramics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)</p> <p>2000-01-01</p> <p>Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water <span class="hlt">vapor</span> as a product of combustion. Oxidation of silica-formers is more rapid in water <span class="hlt">vapor</span> than in oxygen. Parabolic oxidation rates increase with the water <span class="hlt">vapor</span> partial <span class="hlt">pressure</span> with a power law exponent value close to one. Molecular water <span class="hlt">vapor</span> is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water <span class="hlt">vapor</span> <span class="hlt">pressures</span> may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water <span class="hlt">vapor</span> to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial <span class="hlt">pressure</span> of water <span class="hlt">vapor</span>, the total <span class="hlt">pressure</span>, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..DFDL27002P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DFDL27002P"><span>New Models for Velocity/<span class="hlt">Pressure-Gradient</span> Correlations in Turbulent Boundary Layers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poroseva, Svetlana; Murman, Scott</p> <p>2014-11-01</p> <p>To improve the performance of Reynolds-Averaged Navier-Stokes (RANS) turbulence models, one has to improve the accuracy of models for three physical processes: turbulent diffusion, interaction of turbulent <span class="hlt">pressure</span> and velocity fluctuation fields, and dissipative processes. The accuracy of modeling the turbulent diffusion depends on the order of a statistical closure chosen as a basis for a RANS model. When the Gram-Charlier series expansions for the velocity correlations are used to close the set of RANS equations, no assumption on Gaussian turbulence is invoked and no unknown model coefficients are introduced into the modeled equations. In such a way, this closure procedure reduces the modeling uncertainty of fourth-order RANS (FORANS) closures. Experimental and direct numerical simulation data confirmed the validity of using the Gram-Charlier series expansions in various flows including boundary layers. We will address modeling the velocity/<span class="hlt">pressure-gradient</span> correlations. New linear models will be introduced for the second- and higher-order correlations applicable to two-dimensional incompressible wall-bounded flows. Results of models' validation with DNS data in a channel flow and in a zero-<span class="hlt">pressure</span> <span class="hlt">gradient</span> boundary layer over a flat plate will be demonstrated. A part of the material is based upon work supported by NASA under award NNX12AJ61A.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9277520','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9277520"><span>Protein osmotic <span class="hlt">pressure</span> <span class="hlt">gradients</span> and microvascular reflection coefficients.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Drake, R E; Dhother, S; Teague, R A; Gabel, J C</p> <p>1997-08-01</p> <p>Microvascular membranes are heteroporous, so the mean osmotic reflection coefficient for a microvascular membrane (sigma d) is a function of the reflection coefficient for each pore. Investigators have derived equations for sigma d based on the assumption that the protein osmotic <span class="hlt">pressure</span> <span class="hlt">gradient</span> across the membrane (delta II) does not vary from pore to pore. However, for most microvascular membranes, delta II probably does vary from pore to pore. In this study, we derived a new equation for sigma d. According to our equation, pore-to-pore differences in delta II increase the effect of small pores and decrease the effect of large pores on the overall membrane osmotic reflection coefficient. Thus sigma d for a heteroporous membrane may be much higher than previously derived equations indicate. Furthermore, pore-to-pore delta II differences increase the effect of plasma protein osmotic <span class="hlt">pressure</span> to oppose microvascular fluid filtration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940019867&hterms=stress+effects&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dstress%2Beffects','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940019867&hterms=stress+effects&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dstress%2Beffects"><span>Numerical modeling of physical <span class="hlt">vapor</span> transport under microgravity conditions: Effect of thermal creep and stress</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mackowski, Daniel W.; Knight, Roy W.</p> <p>1993-01-01</p> <p>One of the most promising applications of microgravity (micro-g) environments is the manufacture of exotic and high-quality crystals in closed cylindrical ampoules using physical <span class="hlt">vapor</span> transport (PVT) processes. The quality enhancements are believed to be due to the absence of buoyant convection in the weightless environment - resulting in diffusion-limited transport of the <span class="hlt">vapor</span>. In a typical experiment, solid-phase sample material is initially contained at one end of the ampoule. The sample is made to sublime into the <span class="hlt">vapor</span> phase and deposit onto the opposite end by maintaining the source at an elevated temperature with respect to the deposit. Identification of the physical factors governing both the rates and uniformity of crystal growth, and the optimization of the micro-g technology, will require an accurate modeling of the <span class="hlt">vapor</span> transport within the ampoule. Previous micro-g modeling efforts have approached the problem from a 'classical' convective/diffusion formulation, in which convection is driven by the action of buoyancy on thermal and solutal density differences. The general conclusion of these works have been that in low gravity environments the effect of buoyancy on <span class="hlt">vapor</span> transport is negligible, and <span class="hlt">vapor</span> transport occurs in a diffusion-limited mode. However, it has been recently recognized than in the non-isothermal (and often low total <span class="hlt">pressure</span>) conditions encountered in ampoules, the commonly-assumed no-slip boundary condition to the differential equations governing fluid motion can be grossly unrepresentative of the actual situation. Specifically, the temperature <span class="hlt">gradients</span> can give rise to thermal creep flows at the ampoule side walls. In addition, temperature <span class="hlt">gradients</span> in the <span class="hlt">vapor</span> itself can, through the action of thermal stress, lead to bulk fluid convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70016166','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70016166"><span>Aqueous solubilities, <span class="hlt">vapor</span> <span class="hlt">pressures</span>, and 1-octanol-water partition coefficients for C9-C14 linear alkylbenzenes</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sherblom, P.M.; Gschwend, P.M.; Eganhouse, R.P.</p> <p>1992-01-01</p> <p>Measurements and estimates of aqueous solubilities, 1-octanol-water partition coefficients (Kow), and <span class="hlt">vapor</span> <span class="hlt">pressures</span> were made for 29 linear alkylbenzenes having alkyl chain lengths of 9-14 carbons. The ranges of values observed were <span class="hlt">vapor</span> <span class="hlt">pressures</span> from 0.002 to 0.418 Pa, log Kow, from 6.83 to 9.95, and aqueous solubilities from 4 to 38 nmol??L-1. Measured values exhibited a relationship to both the alkyl chain length and the position of phenyl substitution on the alkyl chain. Measurement of the aqueous concentrations resulting from equilibration of a mixture of alkylbenzenes yielded higher than expected values, indicating cosolute or other interactive effects caused enhanced aqueous concentrations of these compounds. ?? 1992 American Chemical Society.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030060500','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030060500"><span>Real-Time Optical Monitoring and Simulations of Gas Phase Kinetics in InN <span class="hlt">Vapor</span> Phase Epitaxy at High <span class="hlt">Pressure</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dietz, Nikolaus; Woods, Vincent; McCall, Sonya D.; Bachmann, Klaus J.</p> <p>2003-01-01</p> <p>Understanding the kinetics of nucleation and coalescence of heteroepitaxial thin films is a crucial step in controlling a chemical <span class="hlt">vapor</span> deposition process, since it defines the perfection of the heteroepitaxial film both in terms of extended defect formation and chemical integrity of the interface. The initial nucleation process also defines the film quality during the later stages of film growth. The growth of emerging new materials heterostructures such as InN or In-rich Ga(x)In(1-x)N require deposition methods operating at higher <span class="hlt">vapor</span> densities due to the high thermal decomposition <span class="hlt">pressure</span> in these materials. High nitrogen <span class="hlt">pressure</span> has been demonstrated to suppress thermal decomposition of InN, but has not been applied yet in chemical <span class="hlt">vapor</span> deposition or etching experiments. Because of the difficulty with maintaining stochiometry at elevated temperature, current knowledge regarding thermodynamic data for InN, e.g., its melting point, temperature-dependent heat capacity, heat and entropy of formation are known with far less accuracy than for InP, InAs and InSb. Also, no information exists regarding the partial <span class="hlt">pressures</span> of nitrogen and phosphorus along the liquidus surfaces of mixed-anion alloys of InN, of which the InN(x)P(1-x) system is the most interesting option. A miscibility gap is expected for InN(x)P(1-x) pseudobinary solidus compositions, but its extent is not established at this point by experimental studies under near equilibrium conditions. The extension of chemical <span class="hlt">vapor</span> deposition to elevated <span class="hlt">pressure</span> is also necessary for retaining stoichiometric single phase surface composition for materials that are characterized by large thermal decomposition <span class="hlt">pressures</span> at optimum processing temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3913518','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3913518"><span>Experimental Study on the Flow Regimes and <span class="hlt">Pressure</span> <span class="hlt">Gradients</span> of Air-Oil-Water Three-Phase Flow in Horizontal Pipes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Al-Hadhrami, Luai M.; Shaahid, S. M.; Tunde, Lukman O.; Al-Sarkhi, A.</p> <p>2014-01-01</p> <p>An experimental investigation has been carried out to study the flow regimes and <span class="hlt">pressure</span> <span class="hlt">gradients</span> of air-oil-water three-phase flows in 2.25 ID horizontal pipe at different flow conditions. The effects of water cuts, liquid and gas velocities on flow patterns and <span class="hlt">pressure</span> <span class="hlt">gradients</span> have been studied. The experiments have been conducted at 20°C using low viscosity Safrasol D80 oil, tap water and air. Superficial water and oil velocities were varied from 0.3 m/s to 3 m/s and air velocity varied from 0.29 m/s to 52.5 m/s to cover wide range of flow patterns. The experiments were performed for 10% to 90% water cuts. The flow patterns were observed and recorded using high speed video camera while the <span class="hlt">pressure</span> drops were measured using <span class="hlt">pressure</span> transducers and U-tube manometers. The flow patterns show strong dependence on water fraction, gas velocities, and liquid velocities. The observed flow patterns are stratified (smooth and wavy), elongated bubble, slug, dispersed bubble, and annular flow patterns. The <span class="hlt">pressure</span> <span class="hlt">gradients</span> have been found to increase with the increase in gas flow rates. Also, for a given superficial gas velocity, the <span class="hlt">pressure</span> <span class="hlt">gradients</span> increased with the increase in the superficial liquid velocity. The <span class="hlt">pressure</span> <span class="hlt">gradient</span> first increases and then decreases with increasing water cut. In general, phase inversion was observed with increase in the water cut. The experimental results have been compared with the existing unified Model and a good agreement has been noticed. PMID:24523645</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24523645','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24523645"><span>Experimental study on the flow regimes and <span class="hlt">pressure</span> <span class="hlt">gradients</span> of air-oil-water three-phase flow in horizontal pipes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Al-Hadhrami, Luai M; Shaahid, S M; Tunde, Lukman O; Al-Sarkhi, A</p> <p>2014-01-01</p> <p>An experimental investigation has been carried out to study the flow regimes and <span class="hlt">pressure</span> <span class="hlt">gradients</span> of air-oil-water three-phase flows in 2.25 ID horizontal pipe at different flow conditions. The effects of water cuts, liquid and gas velocities on flow patterns and <span class="hlt">pressure</span> <span class="hlt">gradients</span> have been studied. The experiments have been conducted at 20 °C using low viscosity Safrasol D80 oil, tap water and air. Superficial water and oil velocities were varied from 0.3 m/s to 3 m/s and air velocity varied from 0.29 m/s to 52.5 m/s to cover wide range of flow patterns. The experiments were performed for 10% to 90% water cuts. The flow patterns were observed and recorded using high speed video camera while the <span class="hlt">pressure</span> drops were measured using <span class="hlt">pressure</span> transducers and U-tube manometers. The flow patterns show strong dependence on water fraction, gas velocities, and liquid velocities. The observed flow patterns are stratified (smooth and wavy), elongated bubble, slug, dispersed bubble, and annular flow patterns. The <span class="hlt">pressure</span> <span class="hlt">gradients</span> have been found to increase with the increase in gas flow rates. Also, for a given superficial gas velocity, the <span class="hlt">pressure</span> <span class="hlt">gradients</span> increased with the increase in the superficial liquid velocity. The <span class="hlt">pressure</span> <span class="hlt">gradient</span> first increases and then decreases with increasing water cut. In general, phase inversion was observed with increase in the water cut. The experimental results have been compared with the existing unified Model and a good agreement has been noticed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810018494','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810018494"><span>Radio jet refraction in galactic atmospheres with static <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Henriksen, R. N.; Vallee, J. P.; Bridle, A. H.</p> <p>1981-01-01</p> <p>A theory of double radio sources which have a 'Z' or 'S' morphology is proposed, based on the refraction of radio jets in the extended atmosphere of an elliptical galaxy. The model describes a collimated jet of supersonic material bending self-consistently under the influence of external static <span class="hlt">pressure</span> <span class="hlt">gradients</span>. Gravity and magnetic fields are neglected in the simplest case except insofar as they determine the static <span class="hlt">pressure</span> distribution. The calculation is a straightforward extension of a method used to calculate a ram-<span class="hlt">pressure</span> model for twin radio trails ('C' morphology). It may also be described as a continuous-jet version of a buoyancy model proposed in 1973. The model has the added virtue of invoking a galactic atmosphere similar to those already indicated by X-ray measurements of some other radio galaxies and by models for the collimation of other radio jets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900004087','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900004087"><span>A <span class="hlt">vapor</span> generator for transonic flow visualization</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bruce, Robert A.; Hess, Robert W.; Rivera, Jose A., Jr.</p> <p>1989-01-01</p> <p>A <span class="hlt">vapor</span> generator was developed for use in the NASA Langley Transonic Dynamics Tunnel (TDT). Propylene glycol was used as the <span class="hlt">vapor</span> material. The <span class="hlt">vapor</span> generator system was evaluated in a laboratory setting and then used in the TDT as part of a laser light sheet flow visualization system. The <span class="hlt">vapor</span> generator provided satisfactory seeding of the air flow with visible condensate particles, smoke, for tests ranging from low subsonic through transonic speeds for tunnel total <span class="hlt">pressures</span> from atmospheric <span class="hlt">pressure</span> down to less than 0.1 atmospheric <span class="hlt">pressure</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24370000','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24370000"><span>Very high <span class="hlt">pressure</span> liquid chromatography using core-shell particles: quantitative analysis of fast <span class="hlt">gradient</span> separations without post-run times.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stankovich, Joseph J; Gritti, Fabrice; Stevenson, Paul G; Beaver, Lois A; Guiochon, Georges</p> <p>2014-01-17</p> <p>Five methods for controlling the mobile phase flow rate for <span class="hlt">gradient</span> elution analyses using very high <span class="hlt">pressure</span> liquid chromatography (VHPLC) were tested to determine thermal stability of the column during rapid <span class="hlt">gradient</span> separations. To obtain rapid separations, instruments are operated at high flow rates and high inlet <span class="hlt">pressure</span> leading to uneven thermal effects across columns and additional time needed to restore thermal equilibrium between successive analyses. The purpose of this study is to investigate means to minimize thermal instability and obtain reliable results by measuring the reproducibility of the results of six replicate <span class="hlt">gradient</span> separations of a nine component RPLC standard mixture under various experimental conditions with no post-run times. <span class="hlt">Gradient</span> separations under different conditions were performed: constant flow rates, two sets of constant <span class="hlt">pressure</span> operation, programmed flow constant <span class="hlt">pressure</span> operation, and conditions which theoretically should yield a constant net heat loss at the column's wall. The results show that using constant flow rates, programmed flow constant <span class="hlt">pressures</span>, and constant heat loss at the column's wall all provide reproducible separations. However, performing separations using a high constant <span class="hlt">pressure</span> with programmed flow reduces the analysis time by 16% compared to constant flow rate methods. For the constant flow rate, programmed flow constant <span class="hlt">pressure</span>, and constant wall heat experiments no equilibration time (post-run time) was required to obtain highly reproducible data. Copyright © 2013 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApPhL.100n1604S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApPhL.100n1604S"><span>Highly ionized physical <span class="hlt">vapor</span> deposition plasma source working at very low <span class="hlt">pressure</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stranak, V.; Herrendorf, A.-P.; Drache, S.; Cada, M.; Hubicka, Z.; Tichy, M.; Hippler, R.</p> <p>2012-04-01</p> <p>Highly ionized discharge for physical <span class="hlt">vapor</span> deposition at very low <span class="hlt">pressure</span> is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of <span class="hlt">pressure</span> during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical <span class="hlt">pressure</span> ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti+ and Ti++ peaks are observed in the mass scan spectra). This corresponds well with high plasma density ne ˜ 1018 m-3, measured during the HiPIMS pulse.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA595262','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA595262"><span>Improved Assessment Strategies for <span class="hlt">Vapor</span> Intrusion Passive Samplers and Building <span class="hlt">Pressure</span> Control</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2013-09-01</p> <p><span class="hlt">pressure</span> control. Matrix Analyte Method Container Holding Time (Days) <span class="hlt">Vapor</span> Radon McHugh , Hammond, Nickels , and Hartman, 2008 Tedlar ® bag 14...2: Diffusive Sampling,” ISO 16017-2:2003. McHugh T. E., D. E. Hammond, T. Nickels , and B. Hartman. 2008. “Use of Radon Measurements for Evaluation...Control I. D. Rivera-Duarte D. B. Chadwick SSC Pacific T. McAlary H. Groenevelt T. Creamer D. Bertrand Geosyntec Consultants, Inc. T. McHugh</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8149707','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8149707"><span>Assessment of coronary artery stenosis <span class="hlt">pressure</span> <span class="hlt">gradient</span> by quantitative coronary arteriography in patients with coronary artery disease.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Atar, D; Ramanujam, P S; Saunamäki, K; Haunsø, S</p> <p>1994-01-01</p> <p>The aim of the study described here was to correlate coronary artery (CA) stenosis <span class="hlt">pressure</span> <span class="hlt">gradients</span> calculated by quantitative coronary arteriography (QCA) to invasively measured transstenotic <span class="hlt">pressure</span> drops in patients with anginal symptoms and with known or suspected coronary artery disease. Furthermore, the known mathematical models are improved by introducing (1) <span class="hlt">pressure</span> catheter-corrected minimal stenosis area, (2) modification of flow assumptions, and (3) stenosis exit angle. Included in the study were 45 patients with 61 stenoses. The visually estimated CA lesion severity in these non-complex stenoses was in the equivocal range of 40-70%. All measurements were performed after intracoronary administration of nifedipine and nitroglycerin. Stenosis dimensions were assessed from magnified cinefilms, using hand-held calipers. Highly significant overall correlation was found between measured and calculated <span class="hlt">pressure</span> <span class="hlt">gradients</span> with correction for the impact of the intracoronary catheter (P < 0.00001, r = 0.84). In particular, a substantial number of stenoses with haemodynamically-insignificant <span class="hlt">pressure</span> <span class="hlt">gradients</span> were identified by hydrodynamic calculations. In conclusion, the great majority of the coronary artery stenoses could be classified reliably by QCA as being haemodynamically insignificant or significant, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990078569&hterms=modeling+reactions+chemical&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmodeling%2Breactions%2Bchemical','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990078569&hterms=modeling+reactions+chemical&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmodeling%2Breactions%2Bchemical"><span>Modeling and Real-Time Process Monitoring of Organometallic Chemical <span class="hlt">Vapor</span> Deposition of III-V Phosphides and Nitrides at Low and High <span class="hlt">Pressure</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bachmann, K. J.; Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Sukidi, N.; McCall, S.</p> <p>1999-01-01</p> <p>The purpose of this paper is to review modeling and real-time monitoring by robust methods of reflectance spectroscopy of organometallic chemical <span class="hlt">vapor</span> deposition (OMCVD) processes in extreme regimes of <span class="hlt">pressure</span>. The merits of p-polarized reflectance spectroscopy under the conditions of chemical beam epitaxy (CBE) and of internal transmission spectroscopy and principal angle spectroscopy at high <span class="hlt">pressure</span> are assessed. In order to extend OMCVD to materials that exhibit large thermal decomposition <span class="hlt">pressure</span> at their optimum growth temperature we have designed and built a differentially-<span class="hlt">pressure</span>-controlled (DCP) OMCVD reactor for use at <span class="hlt">pressures</span> greater than or equal to 6 atm. We also describe a compact hard-shell (CHS) reactor for extending the <span class="hlt">pressure</span> range to 100 atm. At such very high <span class="hlt">pressure</span> the decomposition of source <span class="hlt">vapors</span> occurs in the <span class="hlt">vapor</span> phase, and is coupled to flow dynamics and transport. Rate constants for homogeneous gas phase reactions can be predicted based on a combination of first principles and semi-empirical calculations. The <span class="hlt">pressure</span> dependence of unimolecular rate constants is described by RRKM theory, but requires variational and anharmonicity corrections not included in presently available calculations with the exception of ammonia decomposition. Commercial codes that include chemical reactions and transport exist, but do not adequately cover at present the kinetics of heteroepitaxial crystal growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25172821','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25172821"><span>Incorporating high-<span class="hlt">pressure</span> electroosmotic pump and a nano-flow <span class="hlt">gradient</span> generator into a miniaturized liquid chromatographic system for peptide analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Apeng; Lynch, Kyle B; Wang, Xiaochun; Lu, Joann J; Gu, Congying; Liu, Shaorong</p> <p>2014-09-24</p> <p>We integrate a high-<span class="hlt">pressure</span> electroosmotic pump (EOP), a nanoflow <span class="hlt">gradient</span> generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-<span class="hlt">pressure</span> EOP capable of generating <span class="hlt">pressure</span> of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for <span class="hlt">gradient</span> elutions, generating reproducible <span class="hlt">gradient</span> profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-<span class="hlt">pressure</span> EOP with a nano-flow <span class="hlt">gradient</span> generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow <span class="hlt">gradient</span> elution; the pump rate is stable, and the <span class="hlt">gradient</span> profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations. Copyright © 2014. Published by Elsevier B.V.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29761086','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29761086"><span>Aortic-Brachial Pulse Wave Velocity Ratio: A Measure of Arterial Stiffness <span class="hlt">Gradient</span> Not Affected by Mean Arterial <span class="hlt">Pressure</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fortier, Catherine; Desjardins, Marie-Pier; Agharazii, Mohsen</p> <p>2018-03-01</p> <p>Aortic stiffness, measured by carotid-femoral pulse wave velocity (cf-PWV), is used for the prediction of cardiovascular risk. This mini-review describes the nonlinear relationship between cf-PWV and operational blood <span class="hlt">pressure</span>, presents the proposed methods to adjust for this relationship, and discusses a potential place for aortic-brachial PWV ratio (a measure of arterial stiffness <span class="hlt">gradient</span>) as a blood <span class="hlt">pressure</span>-independent measure of vascular aging. PWV is inherently dependent on the operational blood <span class="hlt">pressure</span>. In cross-sectional studies, PWV adjustment for mean arterial <span class="hlt">pressure</span> (MAP) is preferred, but still remains a nonoptimal approach, as the relationship between PWV and blood <span class="hlt">pressure</span> is nonlinear and varies considerably among individuals due to heterogeneity in genetic background, vascular tone, and vascular remodeling. Extrapolations from the blood <span class="hlt">pressure</span>-independent stiffness parameter β (β 0 ) have led to the creation of stiffness index β, which can be used for local stiffness. A similar approach has been used for cardio-ankle PWV to generate a blood <span class="hlt">pressure</span>-independent cardio-ankle vascular index (CAVI). It was recently demonstrated that stiffness index β and CAVI remain slightly blood <span class="hlt">pressure</span>-dependent, and a more appropriate formula has been proposed to make the proper adjustments. On the other hand, the negative impact of aortic stiffness on clinical outcomes is thought to be mediated through attenuation or reversal of the arterial stiffness <span class="hlt">gradient</span>, which can also be influenced by a reduction in peripheral medium-sized muscular arteries in conditions that predispose to accelerate vascular aging. Arterial stiffness <span class="hlt">gradient</span>, assessed by aortic-brachial PWV ratio, is emerging to be at least as good as cf-PWV for risk prediction, but has the advantage of not being affected by operating MAP. The negative impacts of aortic stiffness on clinical outcomes are proposed to be mediated through attenuation or reversal of arterial stiffness <span class="hlt">gradient</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994MsT.........17M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994MsT.........17M"><span>Compressible turbulence measurements in a supersonic boundary layer including favorable <span class="hlt">pressure</span> <span class="hlt">gradient</span> effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, Raymond S.</p> <p>1994-12-01</p> <p>The effect of a favorable <span class="hlt">pressure</span> <span class="hlt">gradient</span> on the turbulent flow structure in a Mach 2.9 boundary layer (Re/m approximately equal to 1.5 x 10(exp 7)) is investigated experimentally. Conventional flow and hot film measurements of turbulent fluctuation properties have been made upstream of and along an expansion ramp. Upstream measurements were taken in a zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> boundary layer 44 cm from the nozzle throat in a 6.35 cm square test section. Measurements are obtained in the boundary layer, above the expansion ramp, 71.5 cm from the nozzle throat. Mean flow and turbulent flow characteristics are measured in all three dimensions. Comparisons are made between data obtained using single and multiple-overheat cross-wire anemometry as well as conventional mean flow probes. Conventional flow measurements were taken using a Pitot probe and a 10 degree cone static probe. Flow visualization was conducted via imaging techniques (Schlieren and shadowgraph photographs). Results suggest that compressibility effects, as seen through the density fluctuations in the Reynolds shear stress, are roughly 10% relative to the mean velocity and are large relative to the velocity fluctuations. This is also observed in the total Reynolds shear stress; compressibility accounts for 50-75% of the total shear. This is particularly true in the favorable <span class="hlt">pressure</span> <span class="hlt">gradient</span> region, where though the peak fluctuation intensities are diminished, the streamwise component of the mean flow is larger, hence the contribution of the compressibility term is significant in the Reynolds shear.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720006898','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720006898"><span>Oxidation/<span class="hlt">vaporization</span> of silicide coated columbium base alloys</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kohl, F. J.; Stearns, C. A.</p> <p>1971-01-01</p> <p>Mass spectrometric and target collection experiments were made at 1600 K to elucidate the mode of oxidative <span class="hlt">vaporization</span> of two columbium alloys, fused-slurry-coated with a complex silicide former (Si-20Cr-Fe). At oxygen <span class="hlt">pressures</span> up to 0.0005 torr the major <span class="hlt">vapor</span> component detected by mass spectrometry for oxidized samples was gaseous silicon monoxide. Analysis of condensates collected at oxygen <span class="hlt">pressures</span> of 0.1, 1.0 and 10 torr revealed that chromium-, silicon-, iron- and tungsten- containing species were the major products of <span class="hlt">vaporization</span>. Equilibrium thermochemical diagrams were constructed for the metal-oxygen system corresponding to each constituent metal in both the coating and base alloy. The major <span class="hlt">vaporizing</span> species are expected to be the gaseous oxides of chromium, silicon, iron and tungsten. Plots of <span class="hlt">vapor</span> phase composition and maximum <span class="hlt">vaporization</span> rate versus oxygen <span class="hlt">pressure</span> were calculated for each coating constituent. The major contribution to weight loss by <span class="hlt">vaporization</span> at oxygen <span class="hlt">pressures</span> above 1 torr was shown to be the chromium-containing species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25414547','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25414547"><span>A systematic study of atmospheric <span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition growth of large-area monolayer graphene.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Lixin; Zhou, Hailong; Cheng, Rui; Chen, Yu; Lin, Yung-Chen; Qu, Yongquan; Bai, Jingwei; Ivanov, Ivan A; Liu, Gang; Huang, Yu; Duan, Xiangfeng</p> <p>2012-01-28</p> <p>Graphene has attracted considerable interest as a potential material for future electronics. Although mechanical peel is known to produce high quality graphene flakes, practical applications require continuous graphene layers over a large area. The catalyst-assisted chemical <span class="hlt">vapor</span> deposition (CVD) is a promising synthetic method to deliver wafer-sized graphene. Here we present a systematic study on the nucleation and growth of crystallized graphene domains in an atmospheric <span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition (APCVD) process. Parametric studies show that the mean size of the graphene domains increases with increasing growth temperature and CH 4 partial <span class="hlt">pressure</span>, while the density of domains decreases with increasing growth temperature and is independent of the CH 4 partial <span class="hlt">pressure</span>. Our studies show that nucleation of graphene domains on copper substrate is highly dependent on the initial annealing temperature. A two-step synthetic process with higher initial annealing temperature but lower growth temperature is developed to reduce domain density and achieve high quality full-surface coverage of monolayer graphene films. Electrical transport measurements demonstrate that the resulting graphene exhibits a high carrier mobility of up to 3000 cm 2 V -1 s -1 at room temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002798','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002798"><span>Vandenberg Air Force Base <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> Wind Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shafer, Jaclyn A.</p> <p>2013-01-01</p> <p>Warning category winds can adversely impact day-to-day space lift operations at Vandenberg Air Force Base (VAFB) in California. NASA's Launch Services Program and other programs at VAFB use wind forecasts issued by the 30 Operational Support Squadron Weather Flight (30 OSSWF) to determine if they need to limit activities or protect property such as a launch vehicle. The 30 OSSWF tasked the AMU to develop an automated Excel graphical user interface that includes <span class="hlt">pressure</span> <span class="hlt">gradient</span> thresholds between specific observing stations under different synoptic regimes to aid forecasters when issuing wind warnings. This required the AMU to determine if relationships between the variables existed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018NucFu..58d6006S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018NucFu..58d6006S"><span>On the physics of the <span class="hlt">pressure</span> and temperature <span class="hlt">gradients</span> in the edge of tokamak plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stacey, Weston M.</p> <p>2018-04-01</p> <p>An extended plasma fluid theory including atomic physics, radiation, electromagnetic and themodynamic forces, external sources of particles, momentum and energy, and kinetic ion orbit loss is employed to derive theoretical expressions that display the role of the various factors involved in the determination of the <span class="hlt">pressure</span> and temperature <span class="hlt">gradients</span> in the edge of tokamak plasmas. Calculations for current experiments are presented to illustrate the magnitudes of various effects including strong radiative and atomic physics edge cooling effects and strong reduction in ion particle and energy fluxes due to ion orbit loss in the plasma edge. An important new insight is the strong relation between rotation and the edge <span class="hlt">pressure</span> <span class="hlt">gradient</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDG32008A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDG32008A"><span>Experimental Measurements of a High Reynolds Num- ber Adverse <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> Turbulent Boundary Layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Atkinson, Callum; Amili, Omid; Stanislas, Michel; Cuvier, Christophe; Foucaut, Jean-Marc; Srinath, Sricharan; Laval, Jean-Philippe; Kaehler, Christian; Hain, Rainer; Scharnowski, Sven; Schroeder, Andreas; Geisler, Reinhard; Agocs, Janos; Roese, Anni; Willert, Christian; Klinner, Joachim; Soria, Julio</p> <p>2016-11-01</p> <p>The study of adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> turbulent boundary layers is complicated by the need to characterise both the local <span class="hlt">pressure</span> <span class="hlt">gradient</span> and it's upstream flow history. It is therefore necessary to measure a significant streamwise domain at a resolution sufficient to resolve the small scales features. To achieve this collaborative particle image velocimetry (PIV) measurements were performed in the large boundary layer wind-tunnel at the Laboratoire de Mecanique de Lille, including: planar measurements spanning a streamwise domain of 3.5m using 16 cameras covering 15 δ spanwise wall-normal stereo-PIV measurements, high-speed micro-PIV of the near wall region and wall shear stress; and streamwise wall-normal PIV in the viscous sub layer. Details of the measurements and preliminary results will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/870077','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/870077"><span>Calibrated <span class="hlt">vapor</span> generator source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Davies, John P.; Larson, Ronald A.; Goodrich, Lorenzo D.; Hall, Harold J.; Stoddard, Billy D.; Davis, Sean G.; Kaser, Timothy G.; Conrad, Frank J.</p> <p>1995-01-01</p> <p>A portable <span class="hlt">vapor</span> generator is disclosed that can provide a controlled source of chemical <span class="hlt">vapors</span>, such as, narcotic or explosive <span class="hlt">vapors</span>. This source can be used to test and calibrate various types of <span class="hlt">vapor</span> detection systems by providing a known amount of <span class="hlt">vapors</span> to the system. The <span class="hlt">vapor</span> generator is calibrated using a reference ion mobility spectrometer. A method of providing this <span class="hlt">vapor</span> is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of the material) to control the concentration of <span class="hlt">vapors</span> in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of <span class="hlt">vapors</span> at the outlet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/106699','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/106699"><span>Calibrated <span class="hlt">vapor</span> generator source</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.</p> <p>1995-09-26</p> <p>A portable <span class="hlt">vapor</span> generator is disclosed that can provide a controlled source of chemical <span class="hlt">vapors</span>, such as, narcotic or explosive <span class="hlt">vapors</span>. This source can be used to test and calibrate various types of <span class="hlt">vapor</span> detection systems by providing a known amount of <span class="hlt">vapors</span> to the system. The <span class="hlt">vapor</span> generator is calibrated using a reference ion mobility spectrometer. A method of providing this <span class="hlt">vapor</span> is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of the material) to control the concentration of <span class="hlt">vapors</span> in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of <span class="hlt">vapors</span> at the outlet. 10 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26964964','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26964964"><span>Scavenging dissolved oxygen via acoustic droplet <span class="hlt">vaporization</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Radhakrishnan, Kirthi; Holland, Christy K; Haworth, Kevin J</p> <p>2016-07-01</p> <p>Acoustic droplet <span class="hlt">vaporization</span> (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that <span class="hlt">vaporization</span> of a liquid droplet results in a gas microbubble with a diameter 5-6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional <span class="hlt">pressures</span> lower than and greater than the ADV <span class="hlt">pressure</span> amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial <span class="hlt">pressures</span> of gases at equilibrium, was developed. At insonation <span class="hlt">pressures</span> exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation <span class="hlt">pressures</span>, dropping as low as 25% of air saturation within 20s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration <span class="hlt">gradients</span> can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4788814','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4788814"><span>Scavenging dissolved oxygen via acoustic droplet <span class="hlt">vaporization</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>Radhakrishnan, Kirthi; Holland, Christy K.; Haworth, Kevin J.</p> <p>2016-01-01</p> <p>Acoustic droplet <span class="hlt">vaporization</span> (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that <span class="hlt">vaporization</span> of a liquid droplet results in a gas microbubble with a diameter 5 to 6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional <span class="hlt">pressures</span> lower than and greater than the ADV <span class="hlt">pressure</span> amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial <span class="hlt">pressures</span> of gases at equilibrium, was developed. At insonation <span class="hlt">pressures</span> exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation <span class="hlt">pressures</span>, dropping as low as 25% of air saturation within 20 s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration <span class="hlt">gradients</span> can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications. PMID:26964964</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015352','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015352"><span>Experimental Study of a Three-Dimensional Shear-Driven Turbulent Boundary Layer with Streamwise Adverse <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Driver, David M.; Johnston, James P.</p> <p>1990-01-01</p> <p>The effects of a strong adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> on a three-dimensional turbulent boundary layer are studied in an axisymmetric spinning cylinder geometry. Velocity measurements made with a three-component laser Doppler velocimeter include all three mean flow components, all six Reynolds stress components, and all ten triple-product correlations. Reynolds stress diminishes as the flow becomes three-dimensional. Lower levels of shear stress were seen to persist under adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> conditions. This low level of stress was seen to roughly correlate with the magnitude of cross-flow (relative to free stream flow) for this experiment as well as most of the other experiments in the literature. Variations in <span class="hlt">pressure</span> <span class="hlt">gradient</span> do not appear to alter this correlation. For this reason, it is hypothesized that a three-dimensional boundary layer is more prone to separate than a two-dimensional boundary layer, although it could not be directly shown here. None of the computations performed with either a Prandtl mixing length, k-epsilon, or a Launder-Reece-Rodi full Reynolds-stress model were able to predict the reduction in Reynolds stress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29651628','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29651628"><span>Intracranial and Intraocular <span class="hlt">Pressure</span> at the Lamina Cribrosa: <span class="hlt">Gradient</span> Effects.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jóhannesson, Gauti; Eklund, Anders; Lindén, Christina</p> <p>2018-04-12</p> <p>A <span class="hlt">pressure</span> difference between the intraocular and intracranial compartments at the site of the lamina cribrosa has been hypothesized to have a pathophysiological role in several optic nerve head diseases. This paper reviews the current literature on the translamina cribrosa <span class="hlt">pressure</span> difference (TLCPD), the associated <span class="hlt">pressure</span> <span class="hlt">gradient</span>, and its potential pathophysiological role, as well as the methodology to assess TLCPD. For normal-tension glaucoma (NTG), initial studies indicated low intracranial <span class="hlt">pressure</span> (ICP) while recent findings indicate that a reduced ICP is not mandatory. Data from studies on the elevated TLCPD as a pathophysiological factor of NTG are equivocal. From the identification of potential postural effects on the cerebrospinal fluid (CSF) communication between the intracranial and retrolaminar space, we hypothesize that the missing link could be a dysfunction of an occlusion mechanism of the optic nerve sheath around the optic nerve. In upright posture, this could cause an elevated TLCPD even with normal ICP and we suggest that this should be investigated as a pathophysiological component in NTG patients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28703367','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28703367"><span>Temporal relationship between instantaneous <span class="hlt">pressure</span> <span class="hlt">gradients</span> and peak-to-peak systolic ejection <span class="hlt">gradient</span> in congenital aortic stenosis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boe, Brian A; Norris, Mark D; Zampi, Jeffrey D; Rocchini, Albert P; Ensing, Gregory J</p> <p>2017-12-01</p> <p>We sought to identify a time during cardiac ejection when the instantaneous <span class="hlt">pressure</span> <span class="hlt">gradient</span> (IPG) correlated best, and near unity, with peak-to-peak systolic ejection <span class="hlt">gradient</span> (PPSG) in patients with congenital aortic stenosis. Noninvasive echocardiographic measurement of IPG has limited correlation with cardiac catheterization measured PPSG across the spectrum of disease severity of congenital aortic stenosis. A major contributor is the observation that these measures are inherently different with a variable relationship dependent on the degree of stenosis. Hemodynamic data from cardiac catheterizations utilizing simultaneous <span class="hlt">pressure</span> measurements from the left ventricle (LV) and ascending aorta (AAo) in patients with congenital valvar aortic stenosis was retrospectively reviewed over the past 5 years. The cardiac cycle was standardized for all patients using the percentage of total LV ejection time (ET). Instantaneous <span class="hlt">gradient</span> at 5% intervals of ET were compared to PPSG using linear regression and Bland-Altman analysis. A total of 22 patients underwent catheterization at a median age of 13.7 years (interquartile range [IQR] 10.3-18.0) and median weight of 51.1 kg (IQR 34.2-71.6). The PPSG was 46.5 ± 12.6 mm Hg (mean ± SD) and correlated suboptimally with the maximum and mean IPG. The midsystolic IPG (occurring at 50% of ET) had the strongest correlation with the PPSG ( PPSG = 0.97(IPG50%)-1.12, R 2  = 0.88), while the IPG at 55% of ET was closest to unity ( PPSG = 0.997(IPG55%)-1.17, R 2  = 0.87). The commonly measured maximum and mean IPG are suboptimal estimates of the PPSG in congenital aortic stenosis. Using catheter-based data, IPG at 50%-55% of ejection correlates well with PPSG. This may allow for a more accurate estimation of PPSG via noninvasive assessment of IPG. © 2017 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930007702','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930007702"><span><span class="hlt">Vapor</span> phase pyrolysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Steurer, Wolfgang</p> <p>1992-01-01</p> <p>The <span class="hlt">vapor</span> phase pyrolysis process is designed exclusively for the lunar production of oxygen. In this concept, granulated raw material (soil) that consists almost entirely of metal oxides is <span class="hlt">vaporized</span> and the <span class="hlt">vapor</span> is raised to a temperature where it dissociates into suboxides and free oxygen. Rapid cooling of the dissociated <span class="hlt">vapor</span> to a discrete temperature causes condensation of the suboxides, while the oxygen remains essentially intact and can be collected downstream. The gas flow path and flow rate are maintained at an optimum level by control of the <span class="hlt">pressure</span> differential between the <span class="hlt">vaporization</span> region and the oxygen collection system with the aid of the environmental vacuum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IJBm..tmp...31F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IJBm..tmp...31F"><span>The functional dependence of canopy conductance on water <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fuchs, Marcel; Stanghellini, Cecilia</p> <p>2018-03-01</p> <p>Current research seeking to relate between ambient water <span class="hlt">vapor</span> deficit (D) and foliage conductance (g F ) derives a canopy conductance (g W ) from measured transpiration by inverting the coupled transpiration model to yield g W = m - n ln(D) where m and n are fitting parameters. In contrast, this paper demonstrates that the relation between coupled g W and D is g W = AP/D + B, where P is the barometric <span class="hlt">pressure</span>, A is the radiative term, and B is the convective term coefficient of the Penman-Monteith equation. A and B are functions of g F and of meteorological parameters but are mathematically independent of D. Keeping A and B constant implies constancy of g F . With these premises, the derived g W is a hyperbolic function of D resembling the logarithmic expression, in contradiction with the pre-set constancy of g F . Calculations with random inputs that ensure independence between g F and D reproduce published experimental scatter plots that display a dependence between g W and D in contradiction with the premises. For this reason, the dependence of g W on D is a computational artifact unrelated to any real effect of ambient humidity on stomatal aperture and closure. Data collected in a maize field confirm the inadequacy of the logarithmic function to quantify the relation between canopy conductance and <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NRL.....7..496L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NRL.....7..496L"><span>Concentration <span class="hlt">gradient</span> induced morphology evolution of silica nanostructure growth on photoresist-derived carbon micropatterns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Dan; Shi, Tielin; Xi, Shuang; Lai, Wuxing; Liu, Shiyuan; Li, Xiaoping; Tang, Zirong</p> <p>2012-09-01</p> <p>The evolution of silica nanostructure morphology induced by local Si <span class="hlt">vapor</span> source concentration <span class="hlt">gradient</span> has been investigated by a smart design of experiments. Silica nanostructure or their assemblies with different morphologies are obtained on photoresist-derived three-dimensional carbon microelectrode array. At a temperature of 1,000°C, rope-, feather-, and octopus-like nanowire assemblies can be obtained along with the Si <span class="hlt">vapor</span> source concentration <span class="hlt">gradient</span> flow. While at 950°C, stringlike assemblies, bamboo-like nanostructures with large joints, and hollow structures with smaller sizes can be obtained along with the Si <span class="hlt">vapor</span> source concentration <span class="hlt">gradient</span> flow. Both <span class="hlt">vapor</span>-liquid-solid and <span class="hlt">vapor</span>-quasiliquid-solid growth mechanisms have been applied to explain the diverse morphologies involving branching, connecting, and batch growth behaviors. The present approach offers a potential method for precise design and controlled synthesis of nanostructures with different features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860016255','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860016255"><span>Propagation of detonations in hydrazine <span class="hlt">vapor</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heinrich, H. J.</p> <p>1985-01-01</p> <p>In the range of greater hydrazine <span class="hlt">vapor</span> <span class="hlt">pressure</span>, detonation speed depends exclusively on the extent of the ammonia decomposition in the second reaction stage. As <span class="hlt">vapor</span> <span class="hlt">pressure</span> decreases, the ammonia disintegration speed becomes increasingly slower and the reaction reached in the reaction zone increasingly decreases until finally, in the <span class="hlt">vapor</span> <span class="hlt">pressure</span> range between 53 and 16 Torr, the contribution of the second stage to detonation propagation disappears, and only the first stage remains active. Since the disintegration speed of the hydrazine in this <span class="hlt">pressure</span> range has decreased markedly as well, no level, but rather only spinning, detonations occur. Temporary separations of the impact front and the reaction zone in the process lead to fluctuations of the detonation speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=191825&keyword=inverse+AND+control&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=191825&keyword=inverse+AND+control&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>Determination of saturation <span class="hlt">pressure</span> and enthalpy of <span class="hlt">vaporization</span> of semi-volatile aerosols: the integrated volume mentod</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>This study presents the integrated volume method for estimating saturation <span class="hlt">pressure</span> and enthalpy of <span class="hlt">vaporization</span> of a whole aerosol distribution. We measure the change of total volume of an aerosol distribution between a reference state and several heated states, with the heating...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3785717','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3785717"><span>Discovery of the surface polarity <span class="hlt">gradient</span> on iridescent Morpho butterfly scales reveals a mechanism of their selective <span class="hlt">vapor</span> response</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Potyrailo, Radislav A.; Starkey, Timothy A.; Vukusic, Peter; Ghiradella, Helen; Vasudev, Milana; Bunning, Timothy; Naik, Rajesh R.; Tang, Zhexiong; Larsen, Michael; Deng, Tao; Zhong, Sheng; Palacios, Manuel; Grande, James C.; Zorn, Gilad; Goddard, Gregory; Zalubovsky, Sergey</p> <p>2013-01-01</p> <p>For almost a century, the iridescence of tropical Morpho butterfly scales has been known to originate from 3D vertical ridge structures of stacked periodic layers of cuticle separated by air gaps. Here we describe a biological pattern of surface functionality that we have found in these photonic structures. This pattern is a <span class="hlt">gradient</span> of surface polarity of the ridge structures that runs from their polar tops to their less-polar bottoms. This finding shows a biological pattern design that could stimulate numerous technological applications ranging from photonic security tags to self-cleaning surfaces, gas separators, protective clothing, sensors, and many others. As an important first step, this biomaterial property and our knowledge of its basis has allowed us to unveil a general mechanism of selective <span class="hlt">vapor</span> response observed in the photonic Morpho nanostructures. This mechanism of selective <span class="hlt">vapor</span> response brings a multivariable perspective for sensing, where selectivity is achieved within a single chemically graded nanostructured sensing unit, rather than from an array of separate sensors. PMID:24019497</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100027406&hterms=nitrogen+liquid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2527%2Bnitrogen%2Bliquid','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100027406&hterms=nitrogen+liquid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2527%2Bnitrogen%2Bliquid"><span>Thermodynamic Properties of Nitrogen Including Liquid and <span class="hlt">Vapor</span> Phases from 63K to 2000K with <span class="hlt">Pressures</span> to 10,000 Bar</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jacobsen, Richard T.; Stewart, Richard B.</p> <p>1973-01-01</p> <p>Tables of thermodynamic properties of nitrogen are presented for the liquid and <span class="hlt">vapor</span> phases for temperatures from the freezing line to 2000K and <span class="hlt">pressures</span> to 10,000 bar. The tables include values of density, internal energy, enthalpy, entropy, isochoric heat capacity, isobaric heat capacity velocity of sound, the isotherm derivative, and the isochor derivative. The thermodynamic property tables are based on an equation of state, P=P (p,T), which accurately represents liquid and gaseous nitrogen for the range of <span class="hlt">pressures</span> and temperatures covered by the tables. Comparisons of property values calculated from the equation of state with measured values for P-p-T, heat capacity, enthalpy, latent heat, and velocity of sound are included to illustrate the agreement between the experimental data and the tables of properties presented here. The coefficients of the equation of state were determined by a weighted least squares fit to selected P-p-T data and, simultaneously, to isochoric heat capacity data determined by corresponding states analysis from oxygen data, and to data which define the phase equilibrium criteria for the saturated liquid and the saturated <span class="hlt">vapor</span>. The <span class="hlt">vapor</span> <span class="hlt">pressure</span> equation, melting curve equation, and an equation to represent the ideal gas heat capacity are also presented. Estimates of the accuracy of the equation of state, the <span class="hlt">vapor</span> <span class="hlt">pressure</span> equation, and the ideal gas heat capacity equation are given. The equation of state, derivatives of the equation, and the integral functions for calculating derived thermodynamic properties are included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26716880','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26716880"><span><span class="hlt">Vapor</span> <span class="hlt">pressures</span>, thermodynamic stability, and fluorescence properties of three 2,6-alkyl naphthalenes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Santos, Ana Filipa L O M; Oliveira, Juliana A S A; Ribeiro da Silva, Maria D M C; Monte, Manuel J S</p> <p>2016-03-01</p> <p>This work reports the experimental determination of relevant thermodynamic properties and the characterization of luminescence properties of the following polycyclic aromatic hydrocarbons (PAHs): 2,6-diethylnaphthalene, 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene. The standard (p(o) = 0.1 MPa) molar enthalpies of combustion, ΔcHm(o), of the three compounds were determined using static bomb combustion calorimetry. The <span class="hlt">vapor</span> <span class="hlt">pressures</span> of the crystalline phase of 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene were measured at different temperatures using the Knudsen effusion method and the <span class="hlt">vapor</span> <span class="hlt">pressures</span> of both liquid and crystalline phases of 2,6-diethylnaphthalene were measured by means of a static method. The temperatures and the molar enthalpies of fusion of the three compounds were determined using differential scanning calorimetry. The gas-phase molar heat capacities and absolute entropies of the three 2,6-dialkylnaphthalenes studied were determined computationally. The thermodynamic stability of the compounds in both the crystalline and gaseous phases was evaluated by the determination of the Gibbs energies of formation and compared with the ones reported in the literature for 2,6-dimethylnaphthalene. From fluorescence spectroscopy measurements, the optical properties of the compounds studied and of naphthalene were evaluated in solution and in the solid state. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940017963&hterms=water+pressure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwater%2Bpressure','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940017963&hterms=water+pressure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwater%2Bpressure"><span>Temperature/<span class="hlt">pressure</span> and water <span class="hlt">vapor</span> sounding with microwave spectroscopy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Muhleman, D. O.; Janssen, M. A.; Clancy, R. T.; Gulkis, S.; Mccleese, D. J.; Zurek, R.; Haberle, R. M.; Frerking, M.</p> <p>1992-01-01</p> <p>Two intense microwave spectra lines exist in the martian atmosphere that allow unique sounding capabilities: water <span class="hlt">vapor</span> at 183 GHz and the (2-1) rotational line of CO at 230 GHz. Microwave spectra line sounding is a well-developed technique for the Earth's atmosphere for sounding from above from spacecraft and airplanes, and from below from fixed surface sites. Two simple instruments for temperature sounding on Mars (the CO line) and water <span class="hlt">vapor</span> measurements are described. The surface sounder proposed for the MESUR sites is designed to study the boundary layer water <span class="hlt">vapor</span> distribution and the temperature/<span class="hlt">pressure</span> profiles with vertical resolution of 0.25 km up to 1 km with reduced resolution above approaching a scale height. The water channel will be sensitive to a few tenths of a micrometer of water and the temperature profile will be retrieved to an accuracy between 1 and 2 K. The latter is routinely done on the Earth using oxygen lines near 60 GHz. The measurements are done with a single-channel heterodyne receiver looking into a 10-cm mirror that is canned through a range of elevation angles plus a target load. The frequency of the receiver is sweep across the water and CO lines generating the two spectra at about 1-hr intervals throughout the mission. The mass and power for the proposed instrument are 2 kg and 5-8 W continuously. The measurements are completely immune to the atmospheric dust and ice particle loads. It was felt that these measurements are the ultimate ones to properly study the martian boundary layer from the surface to a few kilometers. Sounding from above requires an orbiting spacecraft with multichannel microwave spectrometers such as the instrument proposed for MO by a subset of the authors, a putative MESUR orbiter, and a proposed Discovery mission called MOES. Such an instrument can be built with less than 10 kg and use less than 15 W. The obvious advantage of this approach is that the entire atmosphere can be sounded for temperature and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991ApPhL..59.1438S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991ApPhL..59.1438S"><span>Low-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition of low in situ phosphorus doped silicon thin films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarret, M.; Liba, A.; Bonnaud, O.</p> <p>1991-09-01</p> <p>In situ low phosphorus doped silicon films are deposited onto glass substrates by low-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition method. The deposition parameters, temperature, total <span class="hlt">pressure</span>, and pure silane gas flow are, respectively, fixed at 550 °C, 0.08 Torr, and 50 sccm. The varying deposition parameter is phosphine/silane mole ratio; when this ratio varies from 2×10-6 to 4×10-4, the phosphorus concentration and the resistivity after annealing, respectively, vary from 2×1018 to 3×1020 atoms cm-3 and from 1.5 Ω cm to 2.5×10-3 Ω cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22129011','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22129011"><span>Ice particles trapped by temperature <span class="hlt">gradients</span> at mbar <span class="hlt">pressure</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kelling, Thorben; Wurm, Gerhard; Dürmann, Christoph</p> <p>2011-11-01</p> <p>In laboratory experiments we observe that ice particles (≤100 μm) entrained in a low <span class="hlt">pressure</span> atmosphere (~1 mbar) get trapped by temperature <span class="hlt">gradients</span> between three reservoirs at different temperature. Confining elements are a peltier element at 250 K (bottom), a liquid nitrogen reservoir at 77 K (top), and the surrounding vacuum chamber at 293 K. Particle levitation and trapping is modeled by an interplay of thermophoresis, photophoresis, and gravity. A number of ice particles are trapped simultaneously in close spatial distance to each other at least up to minutes and are accessible for further experiments. © 2011 American Institute of Physics</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011RScI...82k5105K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011RScI...82k5105K"><span>Ice particles trapped by temperature <span class="hlt">gradients</span> at mbar <span class="hlt">pressure</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelling, Thorben; Wurm, Gerhard; Dürmann, Christoph</p> <p>2011-11-01</p> <p>In laboratory experiments we observe that ice particles (⩽100 μm) entrained in a low <span class="hlt">pressure</span> atmosphere (˜1 mbar) get trapped by temperature <span class="hlt">gradients</span> between three reservoirs at different temperature. Confining elements are a peltier element at 250 K (bottom), a liquid nitrogen reservoir at 77 K (top), and the surrounding vacuum chamber at 293 K. Particle levitation and trapping is modeled by an interplay of thermophoresis, photophoresis, and gravity. A number of ice particles are trapped simultaneously in close spatial distance to each other at least up to minutes and are accessible for further experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JEPT...89.1141Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JEPT...89.1141Z"><span>"<span class="hlt">Pressure</span> Blocking" Effect in the Growing <span class="hlt">Vapor</span> Bubble in a Highly Superheated Liquid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zudin, Yu. B.; Zenin, V. V.</p> <p>2016-09-01</p> <p>The problem on the growth of a <span class="hlt">vapor</span> bubble in a liquid whose superheating enthalpy exceeds the phase transition heat has been considered. A physical model of the "<span class="hlt">pressure</span> blocking" in the bubble is presented. The problem for the conditions of the experiment on the effervescence of a butane drop has been solved numerically. An algorithm for constructing an analytical solution of the problem on the bubble growth in a highly superheated liquid is proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020023588&hterms=Beer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBeer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020023588&hterms=Beer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBeer"><span>Beer Law Constants and <span class="hlt">Vapor</span> <span class="hlt">Pressures</span> of HgI2 over HgI2(s,l)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.; Whitaker, Ann F. (Technical Monitor)</p> <p>2001-01-01</p> <p>The optical absorption spectra of the <span class="hlt">vapor</span> phase over HgI2(s,l) were measured for wavelengths between 200 and 600 nm. The spectra show that the sample sublimed congruently into HgI2 with no Hg or I2 absorption spectrum observed. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were determined. From these constants the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of H912, P, was established as a function of temperatures for the liquid and the solid Beta-phases. The expressions correspond to the enthalpies of <span class="hlt">vaporization</span> and sublimation of 15.30 and 20.17 Kcal/mole, respectively, for the liquid and the Beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 Kcal/mole and the intersection of the two expressions gives a melting point of 537 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27165918','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27165918"><span>Automatic Calculation of Hydrostatic <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> in Patients with Head Injury: A Pilot Study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moss, Laura; Shaw, Martin; Piper, Ian; Arvind, D K; Hawthorne, Christopher</p> <p>2016-01-01</p> <p>The non-surgical management of patients with traumatic brain injury is the treatment and prevention of secondary insults, such as low cerebral perfusion <span class="hlt">pressure</span> (CPP). Most clinical <span class="hlt">pressure</span> monitoring systems measure <span class="hlt">pressure</span> relative to atmospheric <span class="hlt">pressure</span>. If a patient is managed with their head tilted up, relative to their arterial <span class="hlt">pressure</span> transducer, then a hydrostatic <span class="hlt">pressure</span> <span class="hlt">gradient</span> (HPG) can act against arterial <span class="hlt">pressure</span> and cause significant errors in calculated CPP.To correct for HPG, the arterial <span class="hlt">pressure</span> transducer should be placed level with the intracranial <span class="hlt">pressure</span> transducer. However, this is not always achieved. In this chapter, we describe a pilot study investigating the application of speckled computing (or "specks") for the automatic monitoring of the patient's head tilt and subsequent automatic calculation of HPG. In future applications this will allow us to automatically correct CPP to take into account any HPG.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020086971&hterms=Shrink&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DShrink','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020086971&hterms=Shrink&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DShrink"><span>The Collapse of <span class="hlt">Vapor</span> Bubbles in a Spatially Non-Uniform Flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hao, Y.; Prosperetti, A.</p> <p>2000-01-01</p> <p><span class="hlt">Pressure</span> <span class="hlt">gradients</span> act differently on liquid particles and suspended bubbles and are, therefore, capable of inducing a relative motion between the phases even when no relative velocity initially exists. As a consequence of the enhanced heat transfer in the presence of convection, this fact may have a major impact on the evolution of a <span class="hlt">vapor</span> bubble. The effect is particularly strong in the case of a collapsing bubble for which, due to the conservation of the system's impulse, the induced relative velocity tends to be magnified when the bubble volume shrinks. A practical application could be, for instance, the enhancement of the condensation rate of bubbles downstream of a heated region, thereby reducing the quality of a flowing liquid-<span class="hlt">vapor</span> mixture. A simple model of the process, in which the bubble is assumed to be spherical and the flow potential, is developed in the paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AnRFM..49..221P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AnRFM..49..221P"><span><span class="hlt">Vapor</span> Bubbles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prosperetti, Andrea</p> <p>2017-01-01</p> <p>This article reviews the fundamental physics of <span class="hlt">vapor</span> bubbles in liquids. Work on bubble growth and condensation for stationary and translating bubbles is summarized and the differences with bubbles containing a permanent gas stressed. In particular, it is shown that the natural frequency of a <span class="hlt">vapor</span> bubble is proportional not to the inverse radius, as for a gas bubble, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the bubble with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of <span class="hlt">pressure</span> waves in a <span class="hlt">vaporous</span> bubbly liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and <span class="hlt">vapor</span> bubbles in an immiscible liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960015858','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960015858"><span>A Study of the Development of Steady and Periodic Unsteady Turbulent Wakes Through Curved Channels at Positive, Zero, and Negative Streamwise <span class="hlt">Pressure</span> <span class="hlt">Gradients</span>, Part 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schobeiri, M. T.; John, J.</p> <p>1996-01-01</p> <p>The turbomachinery wake flow development is largely influenced by streamline curvature and streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The objective of this investigation is to study the development of the wake under the influence of streamline curvature and streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The experimental investigation is carried out in two phases. The first phase involves the study of the wake behind a stationary circular cylinder (steady wake) in curved channels at positive, zero, and negative streamwise <span class="hlt">pressure</span> <span class="hlt">gradients</span>. The mean velocity and Reynolds stress components are measured using a X-hot-film probe. The measured quantities obtained in probe coordinates are transformed to a curvilinear coordinate system along the wake centerline and are presented in similarity coordinates. The results of the steady wakes suggest strong asymmetry in velocity and Reynolds stress components. However, the velocity defect profiles in similarity coordinates are almost symmetrical and follow the same distribution as the zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> straight wake. The results of Reynolds stress distributions show higher values on the inner side of the wake than the outer side. Other quantities, including the decay of maximum velocity defect, growth of wake width, and wake integral parameters, are also presented for the three different <span class="hlt">pressure</span> <span class="hlt">gradient</span> cases of steady wake. The decay rate of velocity defect is fastest for the negative streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span> case and slowest for the positive <span class="hlt">pressure</span> <span class="hlt">gradient</span> case. Conversely, the growth of the wake width is fastest for the positive streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span> case and slowest for the negative streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The second phase studies the development of periodic unsteady wakes generated by the circular cylinders of the rotating wake generator in a curved channel at zero streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span>. Instantaneous velocity components of the periodic unsteady wakes, measured with a stationary X-hot-film probe, are analyzed by the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JPhCS.821a2022S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JPhCS.821a2022S"><span>Preliminary characterization of an expanding flow of siloxane <span class="hlt">vapor</span> MDM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spinelli, A.; Cozzi, F.; Cammi, G.; Zocca, M.; Gaetani, P.; Dossena, V.; Guardone, A.</p> <p>2017-03-01</p> <p>The early experimental results on the characterization of expanding flows of siloxane <span class="hlt">vapor</span> MDM (C8H24O2Si3, octamethyltrisiloxane) are presented. The measurements were performed on the Test Rig for Organic <span class="hlt">VApors</span> (TROVA) at the CREA Laboratory of Politecnico di Milano. The TROVA test-rig was built in order to investigate the non-ideal compressible-fluid behavior of typical expanding flows occurring within organic Rankine cycles (ORC) turbine passages. The test rig implements a batch Rankine cycle where a planar converging-diverging nozzle replaces the turbine and represents a test section. Investigations related to both fields of non-ideal compressible-fluid dynamics fundamentals and turbomachinery are allowed. The nozzle can be operated with different working fluids and operating conditions aiming at measuring independently the <span class="hlt">pressure</span>, the temperature and the velocity field and thus providing data to verify the thermo-fluid dynamic models adopted to predict the behavior of these flows. The limiting values of <span class="hlt">pressure</span> and temperature are 50 bar and 400 °C respectively. The early measurements are performed along the nozzle axis, where an isentropic process is expected to occur. In particular, the results reported here refer to the nozzle operated in adapted conditions using the siloxane <span class="hlt">vapor</span> MDM as working fluid in thermodynamic regions where mild to medium non-ideal compressible-fluid effects are present. Both total temperature and total <span class="hlt">pressure</span> of the nozzle are measured upstream of the test section, while static <span class="hlt">pressure</span> are measured along the nozzle axis. Schlieren visualizations are also carried out in order to complement the <span class="hlt">pressure</span> measurement with information about the 2D density <span class="hlt">gradient</span> field. The Laser Doppler Velocimetry technique is planned to be used in the future for velocity measurements. The measured flow field has also been interpreted by resorting to the quasi-one-dimensional theory and two dimensional CFD viscous calculation. In both cases</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SPIE10240E..0HW','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10240E..0HW"><span>Accelerating <span class="hlt">gradient</span> improvement using shape-tailor laser front in radiation <span class="hlt">pressure</span> acceleration progress</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, W. P.; Shen, B. F.; Xu, Z. Z.</p> <p>2017-05-01</p> <p>The accelerating <span class="hlt">gradient</span> of a proton beam is crucial for stable radiation <span class="hlt">pressure</span> acceleration (RPA) because the multi-dimensional instabilities increase γ times slower in the relativistic region. In this paper, a shape-tailored laser is proposed to significantly accelerate the ions in a controllable high accelerating <span class="hlt">gradient</span>. In this method, the fastest ions initially rest in the middle of the foil are controlled to catch the compressed electron layer at the end of the hole-boring stage, thus the light-sail stage can start as soon as possible. Then the compressed electron layer is accelerated tightly together with the fastest ions by the shaped laser intensity, which further increases the accelerating <span class="hlt">gradient</span> in the light-sail stage. Such tailored pulse may be beneficial for the RPA driven by the 10-fs 10 petawatt laser in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23646728','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23646728"><span>Adsorption and desorption characteristics of <span class="hlt">gradient</span> distributed Bragg reflector porous silicon layers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Um, Sungyong; Lee, Sung Gi; Woo, Hee-Gweon; Cho, Sungdong; Sohn, Honglae</p> <p>2013-01-01</p> <p>Adsorption and desorption characteristics of <span class="hlt">gradient</span> distributed Bragg reflector (DBR) porous silicon (PSi) were investigated under the exposure of organic <span class="hlt">vapors</span>. <span class="hlt">Gradient</span> DBR PSi whose average pore size decreased as the lateral distance from the Pt electrode increased was generated by using an asymmetric etching configuration. The reflection resonances were measured as a function of lateral distance from a point closest to the plate Pt electrode to a position on the silicon surface. Two types of <span class="hlt">gradient</span> DBR PSi (H- and HO-terminated <span class="hlt">gradient</span> DBR PSi) were used in this study. The detection of volatile organic compounds (VOCs) using the <span class="hlt">gradient</span> DBR PSi had been achieved. When the <span class="hlt">vapor</span> of VOCs condensed in the nanopores, the <span class="hlt">gradient</span> DBR PSi modified with hydrophobic and hydrophilic functionality exhibited different pore adsorption and desorption characteristics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110012600','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110012600"><span>Passive <span class="hlt">Vaporizing</span> Heat Sink</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.</p> <p>2011-01-01</p> <p>A passive <span class="hlt">vaporizing</span> heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a <span class="hlt">pressure</span>-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The <span class="hlt">vapor</span> of the liquid escapes when the temperature exceeds the boiling point corresponding to the <span class="hlt">vapor</span> <span class="hlt">pressure</span> determined by the setting of the <span class="hlt">pressure</span>-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of <span class="hlt">vaporization</span>, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1299488','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1299488"><span>Effect of substrate roughness on D spacing supports theoretical resolution of <span class="hlt">vapor</span> <span class="hlt">pressure</span> paradox.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tristram-Nagle, S; Petrache, H I; Suter, R M; Nagle, J F</p> <p>1998-01-01</p> <p>The lamellar D spacing has been measured for oriented stacks of lecithin bilayers prepared on a variety of solid substrates and hydrated from the <span class="hlt">vapor</span>. We find that, when the bilayers are in the L(alpha) phase near 100% relative humidity, the D spacing is consistently larger when the substrate is rougher than when it is smooth. The differences become smaller as the relative humidity is decreased to 80% and negligible differences are seen in the L(beta') phase. Our interpretation is that rough substrates frustrate the bilayer stack energetically, thereby increasing the fluctuations, the fluctuational repulsive forces, and the water spacing compared with stacks on smooth surfaces. This interpretation is consistent with and provides experimental support for a recently proposed theoretical resolution of the <span class="hlt">vapor</span> <span class="hlt">pressure</span> paradox. PMID:9512038</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=ideal+AND+gas+AND+law&pg=4&id=EJ088264','ERIC'); return false;" href="https://eric.ed.gov/?q=ideal+AND+gas+AND+law&pg=4&id=EJ088264"><span><span class="hlt">Pressure</span> (Or No Royal Road)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Bradley, J.</p> <p>1973-01-01</p> <p>Discusses how difficult the various problems of <span class="hlt">pressure</span>, partial <span class="hlt">pressure</span>, gas laws, and <span class="hlt">vapor</span> <span class="hlt">pressure</span> are for students. Outlines the evolution of the concept of <span class="hlt">pressure</span>, the gas equation for a perfect gas, partial <span class="hlt">pressures</span>, saturated <span class="hlt">vapor</span> <span class="hlt">pressure</span>, Avogadro's hypothesis, Raoult's law, and the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of ideal solutions. (JR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AIPA....7l5310K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPA....7l5310K"><span>Two dimensional radial gas flows in atmospheric <span class="hlt">pressure</span> plasma-enhanced chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae</p> <p>2017-12-01</p> <p>Atmospheric <span class="hlt">pressure</span> (AP) operation of plasma-enhanced chemical <span class="hlt">vapor</span> deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial <span class="hlt">pressure</span>, hydrogen partial <span class="hlt">pressure</span>, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020024643','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020024643"><span>Flow Control Device Evaluation for an Internal Flow with an Adverse <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jenkins, Luther N.; Gorton, Susan Althoff; Anders, Scott G.</p> <p>2002-01-01</p> <p>The effectiveness of several active and passive devices to control flow in an adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> with secondary flows present was evaluated in the 15 Inch Low Speed Tunnel at NASA Langley Research Center. In this study, passive micro vortex generators, micro bumps, and piezoelectric synthetic jets were evaluated for their flow control characteristics using surface static <span class="hlt">pressures</span>, flow visualization, and 3D Stereo Digital Particle Image Velocimetry. Data also were acquired for synthetic jet actuators in a zero flow environment. It was found that the micro vortex generator is very effective in controlling the flow environment for an adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span>, even in the presence of secondary vortical flow. The mechanism by which the control is effected is a re-energization of the boundary layer through flow mixing. The piezoelectric synthetic jet actuators must have sufficient velocity output to produce strong longitudinal vortices if they are to be effective for flow control. The output of these devices in a laboratory or zero flow environment will be different than the output in a flow environment. In this investigation, the output was higher in the flow environment, but the stroke cycle in the flow did not indicate a positive inflow into the synthetic jet.</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('https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=308904','PESTICIDES'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=308904"><span>Assessment of Mitigation Systems on <span class="hlt">Vapor</span> Intrusion ...</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p><span class="hlt">Vapor</span> intrusion is the migration of subsurface <span class="hlt">vapors</span>, including radon and volatile organic compounds (VOCs), in soil gas from the subsurface to indoor air. <span class="hlt">Vapor</span> intrusion happens because there are <span class="hlt">pressure</span> and concentration differentials between indoor air and soil gas. Indoor environments are often negatively <span class="hlt">pressurized</span> with respect to outdoor air and soil gas (for example, from exhaust fans or the stack effect), and this <span class="hlt">pressure</span> difference allows soil gas containing subsurface <span class="hlt">vapors</span> to flow into indoor air through advection. In addition, concentration differentials cause VOCs and radon to migrate from areas of higher to lower concentrations through diffusion, which is another cause of <span class="hlt">vapor</span> intrusion. Current practice for evaluating the <span class="hlt">vapor</span> intrusion pathway involves a multiple line of evidence approach based on direct measurements in groundwater, external soil gas, subslab soil gas, and/or indoor air. No single line of evidence is considered definitive, and direct measurements of <span class="hlt">vapor</span> intrusion can be costly, especially where significant spatial and temporal variability require repeated measurements at multiple locations to accurately assess the chronic risks of long-term exposure to volatile organic compounds (VOCs) like chloroform, perchloroethylene (PCE), and trichloroethylene (TCE).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6915641-liquid-densities-vapor-pressures-chloro-difluorethane-hcfc','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6915641-liquid-densities-vapor-pressures-chloro-difluorethane-hcfc"><span>Liquid densities and <span class="hlt">vapor</span> <span class="hlt">pressures</span> of 1-chloro-1, 1-difluorethane (HCFC 142b)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Maezawa, Yl; Sato, H.; Watanabe, K.</p> <p>1991-04-01</p> <p>In this paper, thirty-six saturated liquid densities of HCFC 142b (1-chloro-1,1-difluoroethane) are measured in a range of temperatures from 210 to 400 K. Twelve <span class="hlt">vapor</span> <span class="hlt">pressures</span>, from 320 to 400 K, and six compressed liquid PVT properties, from 320 to 360 K and of <span class="hlt">pressures</span> up to 2 MPa, are also measured. All measurements were made by a magnetic densimeter coupled with a variable volume cell. The experimental uncertainties in temperature, <span class="hlt">pressure</span>, and density were estimated to be not greater than [plus minus]15 mK, [plus minus]10 kPa, and [plus minus]0.2%, respectively. The purity of the sample used was 99.8 wtmore » % or better. The simple correlation for the saturated liquid density of HCFC 142b was developed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890064727&hterms=chloride&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dchloride','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890064727&hterms=chloride&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dchloride"><span>Effect of temperature <span class="hlt">gradient</span> on the optical quality of mercurous chloride crystals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Singh, N. B.; Davies, D. K.; Gottlieb, M.; Henningsen, T.; Mazelsky, R.</p> <p>1989-01-01</p> <p>Single crystals of mercurous chloride were grown at temperature <span class="hlt">gradients</span> of 8, 11 and 17 K/cm by the physical <span class="hlt">vapor</span> transport method. The optical quality of these crystals was evaluated by measuring bulk scattering and inhomogeneity of refractive index by birefringence interferometry. It was observed that a high temperature <span class="hlt">gradient</span> at the solid-<span class="hlt">vapor</span> interface induced thermal stresses and crystals showed higher scattering and irregular fringes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/868967','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/868967"><span>Chemical <span class="hlt">vapor</span> infiltration using microwave energy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Devlin, David J.; Currier, Robert P.; Laia, Jr., Joseph R.; Barbero, Robert S.</p> <p>1993-01-01</p> <p>A method for producing reinforced ceramic composite articles by means of chemical <span class="hlt">vapor</span> infiltration and deposition in which an inverted temperature <span class="hlt">gradient</span> is utilized. Microwave energy is the source of heat for the process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22494683-gas-phase-emitter-effect-lanthanum-within-ceramic-metal-halide-lamps-its-dependence-la-vapor-pressure-operating-frequency','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22494683-gas-phase-emitter-effect-lanthanum-within-ceramic-metal-halide-lamps-its-dependence-la-vapor-pressure-operating-frequency"><span>The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La <span class="hlt">vapor</span> <span class="hlt">pressure</span> and operating frequency</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ruhrmann, C.; Hoebing, T.; Bergner, A.</p> <p>2015-08-07</p> <p>The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth <span class="hlt">pressures</span>. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are <span class="hlt">vaporized</span>, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emittermore » effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La <span class="hlt">vapor</span> <span class="hlt">pressure</span> within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La <span class="hlt">vapor</span> <span class="hlt">pressure</span> is raised by a heating of the cold spot. In this way, conditions depending on the La <span class="hlt">vapor</span> <span class="hlt">pressure</span> and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ApPhL.112x1903X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ApPhL.112x1903X"><span>Gas-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> transport growth of millimeter-sized c-BAs single crystals with moderate thermal conductivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xing, Jie; Glaser, Evan R.; Song, Bai; Culbertson, James C.; Freitas, Jaime A.; Duncan, Ryan A.; Nelson, Keith A.; Chen, Gang; Ni, Ni</p> <p>2018-06-01</p> <p>We have grown c-BAs single crystals up to 1000 μm size by the chemical <span class="hlt">vapor</span> transport (CVT) technique using combined As and I2 transport agents with the As:I ratio of 1:3 under gas <span class="hlt">pressures</span> of up to 35 atm. Raman spectroscopy revealed a very sharp (˜2.4 cm-1) P1 phonon mode and an interesting splitting behavior of P1 from detailed polarization studies. Electron paramagnetic resonance (EPR) experiments revealed no evidence for EPR active growth-related defects under the experimental resolution. Finally, a moderate thermal conductivity value of ˜132 W/m-K was obtained using a transient thermal grating technique. These results suggest that although the high As gas <span class="hlt">vapor</span> <span class="hlt">pressure</span> environment in CVT growth can increase the transport rate of c-BAs significantly, it may not be efficient in reducing the defects and enhancing the thermal conductivity in c-BAs significantly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720041568&hterms=carbon+balance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dcarbon%2Bbalance','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720041568&hterms=carbon+balance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dcarbon%2Bbalance"><span><span class="hlt">Vaporization</span> characteristics of carbon heat shields under radiative heating.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Davy, W. C.; Bar-Nun, A.</p> <p>1972-01-01</p> <p>Study of the <span class="hlt">vaporization</span> characteristics of samples of ATJ graphite, a material that has been considered for use on a Jovian probe. These samples were subjected to radiative heating loads of approximately 2 kW/sq cm in argon atmospheres of <span class="hlt">pressures</span> from 0.00046 to 1 atm. Surface temperatures, mass loss rates, and spatially resolved emission spectral data were recorded. These data are analyzed to determine carbon <span class="hlt">vapor</span> <span class="hlt">pressure</span> as a function of temperature and are compared with current models for the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of carbon. The effects of finite <span class="hlt">vaporization</span> (i.e., nonequilibrium) rates are considered and compared with experiment. Estimates of the heat of <span class="hlt">vaporization</span> from an energy balance are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29883002','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29883002"><span>Highly Efficient 2D/3D Hybrid Perovskite Solar Cells via Low-<span class="hlt">Pressure</span> <span class="hlt">Vapor</span>-Assisted Solution Process.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Ming-Hsien; Yeh, Hung-Hsiang; Chiang, Yu-Hsien; Jeng, U-Ser; Su, Chun-Jen; Shiu, Hung-Wei; Hsu, Yao-Jane; Kosugi, Nobuhiro; Ohigashi, Takuji; Chen, Yu-An; Shen, Po-Shen; Chen, Peter; Guo, Tzung-Fang</p> <p>2018-06-08</p> <p>The fabrication of multidimensional organometallic halide perovskite via a low-<span class="hlt">pressure</span> <span class="hlt">vapor</span>-assisted solution process is demonstrated for the first time. Phenyl ethyl-ammonium iodide (PEAI)-doped lead iodide (PbI 2 ) is first spin-coated onto the substrate and subsequently reacts with methyl-ammonium iodide (MAI) <span class="hlt">vapor</span> in a low-<span class="hlt">pressure</span> heating oven. The doping ratio of PEAI in MAI-<span class="hlt">vapor</span>-treated perovskite has significant impact on the crystalline structure, surface morphology, grain size, UV-vis absorption and photoluminescence spectra, and the resultant device performance. Multiple photoluminescence spectra are observed in the perovskite film starting with high PEAI/PbI 2 ratio, which suggests the coexistence of low-dimensional perovskite (PEA 2 MA n -1 Pb n I 3 n +1 ) with various values of n after <span class="hlt">vapor</span> reaction. The dimensionality of the as-fabricated perovskite film reveals an evolution from 2D, hybrid 2D/3D to 3D structure when the doping level of PEAI/PbI 2 ratio varies from 2 to 0. Scanning electron microscopy images and Kelvin probe force microscopy mapping show that the PEAI-containing perovskite grain is presumably formed around the MAPbI 3 perovskite grain to benefit MAPbI 3 grain growth. The device employing perovskite with PEAI/PbI 2 = 0.05 achieves a champion power conversion efficiency of 19.10% with an open-circuit voltage of 1.08 V, a current density of 21.91 mA cm -2 , and a remarkable fill factor of 80.36%. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25753157','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25753157"><span>MRI measurements of intracranial <span class="hlt">pressure</span> in the upright posture: The effect of the hydrostatic <span class="hlt">pressure</span> <span class="hlt">gradient</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alperin, Noam; Lee, Sang H; Bagci, Ahmet M</p> <p>2015-10-01</p> <p>To add the hydrostatic component of the cerebrospinal fluid (CSF) <span class="hlt">pressure</span> to magnetic resonance imaging (MRI)-derived intracranial <span class="hlt">pressure</span> (ICP) measurements in the upright posture for derivation of <span class="hlt">pressure</span> value in a central cranial location often used in invasive ICP measurements. Additional analyses were performed using data previously collected from 10 healthy subjects scanned in supine and sitting positions with a 0.5T vertical gap MRI scanner (GE Medical). Pulsatile blood and CSF flows to and from the brain were quantified using cine phase-contrast. Intracranial compliance and <span class="hlt">pressure</span> were calculated using a previously described method. The vertical distance between the location of the CSF flow measurement and a central cranial location was measured manually in the mid-sagittal T1 -weighted image obtained in the upright posture. The hydrostatic <span class="hlt">pressure</span> <span class="hlt">gradient</span> of a CSF column with similar height was then added to the MR-ICP value. After adjustment for the hydrostatic component, the mean ICP value was reduced by 7.6 mmHg. Mean ICP referenced to the central cranial level was -3.4 ± 1.7 mmHg compared to the unadjusted value of +4.3 ± 1.8 mmHg. In the upright posture, the hydrostatic <span class="hlt">pressure</span> component needs to be added to the MRI-derived ICP values for compatibility with invasive ICP at a central cranial location. © 2015 Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930088097','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930088097"><span><span class="hlt">Vapor</span> <span class="hlt">pressures</span> and calculated heats of <span class="hlt">vaporization</span> of concentrated nitric acid solutions in the composition range 71 to 89 percent nitrogen dioxide, 1 to 10 percent water, and in the temperature range 10 to 60 degrees C</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mckeown, A B; Belles, Frank E</p> <p>1954-01-01</p> <p>Total <span class="hlt">vapor</span> <span class="hlt">pressures</span> were measured for 16 acid mixtures of the ternary system nitric acid, nitrogen dioxide, and water within the temperature range 10 degrees to 60 degrees Celsius, and with the composition range 71 to 89 weight percent nitric acid, 7 to 20 weight percent nitrogen dioxide, and 1 to 10 weight percent water. Heats of <span class="hlt">vaporization</span> were calculated from the <span class="hlt">vapor</span> <span class="hlt">pressure</span> measurements for each sample for the temperatures 25, 40, and 60 degrees Celsius. The ullage of the apparatus used for the measurements was 0.46. Ternary diagrams showing isobars as a function of composition of the system were constructed from experimental and interpolated data for the temperatures 25, 40, 45, and 60 degrees C and are presented herein.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950014614','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950014614"><span>Wake measurements in a strong adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoffenberg, R.; Sullivan, John P.; Schneider, S. P.</p> <p>1994-01-01</p> <p>The behavior of wakes in adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> is critical to the performance of high-lift systems for transport aircraft. Wake deceleration is known to lead to sudden thickening and the onset of reversed flow; this 'wake bursting' phenomenon can occur while surface flows remain attached. Although 'wake bursting' is known to be important for high-lift systems, no detailed measurements of 'burst' wakes have ever been reported. Wake bursting has been successfully achieved in the wake of a flat plate as it decelerated in a two-dimensional diffuser, whose sidewalls were forced to remain attached by use of slot blowing. Pilot probe surveys, L.D.V. measurements, and flow visualization have been used to investigate the physics of this decelerated wake, through the onset of reversed flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26940013','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26940013"><span>Cardiomyopathy in children: Can we rely on echocardiographic tricuspid regurgitation <span class="hlt">gradient</span> estimates of right ventricular and pulmonary arterial <span class="hlt">pressure</span>?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Simon; Lytrivi, Irene D; Roytman, Zhanna; Ko, Hyun-Sook Helen; Vinograd, Cheryl; Srivastava, Shubhika</p> <p>2016-10-01</p> <p>Introduction Agreement between echocardiography and right heart catheterisation-derived right ventricular systolic <span class="hlt">pressure</span> is modest in the adult heart failure population, but is unknown in the paediatric cardiomyopathy population. All patients at a single centre from 2001 to 2012 with a diagnosis of cardiomyopathy who underwent echocardiography and catheterisation within 30 days were included in this study. The correlation between tricuspid regurgitation <span class="hlt">gradient</span> and catheterisation-derived right ventricular systolic <span class="hlt">pressure</span> and mean pulmonary artery <span class="hlt">pressure</span> was determined. Agreement between echocardiography and catheterisation-derived right ventricular systolic <span class="hlt">pressure</span> was assessed using Bland-Altman plots. Analysis was repeated for patients who underwent both procedures within 7 days. Haemodynamic data from those with poor agreement and good agreement between echocardiography and catheterisation were compared. A total of 37 patients who underwent 48 catheterisation procedures were included in our study. The median age was 11.8 (0.1-20.6 years) with 22 males (58% total). There was a modest correlation (r=0.65) between echocardiography and catheterisation-derived right ventricular systolic <span class="hlt">pressure</span>, but agreement was poor. Agreement between tricuspid regurgitation <span class="hlt">gradient</span> and right ventricular systolic <span class="hlt">pressure</span> showed wide 95% limits of agreement. There was a modest correlation between the tricuspid regurgitation <span class="hlt">gradient</span> and mean pulmonary artery <span class="hlt">pressure</span> (r=0.6). Shorter time interval between the two studies did not improve agreement. Those with poor agreement between echocardiography and catheterisation had higher right heart <span class="hlt">pressures</span>, but this difference became insignificant after accounting for right atrial <span class="hlt">pressure</span>. Transthoracic echocardiography estimation of right ventricular systolic <span class="hlt">pressure</span> shows modest correlation with right heart <span class="hlt">pressures</span>, but has limited agreement and may underestimate the degree of pulmonary hypertension in paediatric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830054819&hterms=employment+work&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Demployment%2Bwork','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830054819&hterms=employment+work&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Demployment%2Bwork"><span>A comparison of methods for computing the sigma-coordinate <span class="hlt">pressure</span> <span class="hlt">gradient</span> force for flow over sloped terrain in a hybrid theta-sigma model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Johnson, D. R.; Uccellini, L. W.</p> <p>1983-01-01</p> <p>In connection with the employment of the sigma coordinates introduced by Phillips (1957), problems can arise regarding an accurate finite-difference computation of the <span class="hlt">pressure</span> <span class="hlt">gradient</span> force. Over steeply sloped terrain, the calculation of the sigma-coordinate <span class="hlt">pressure</span> <span class="hlt">gradient</span> force involves computing the difference between two large terms of opposite sign which results in large truncation error. To reduce the truncation error, several finite-difference methods have been designed and implemented. The present investigation has the objective to provide another method of computing the sigma-coordinate <span class="hlt">pressure</span> <span class="hlt">gradient</span> force. Phillips' method is applied for the elimination of a hydrostatic component to a flux formulation. The new technique is compared with four other methods for computing the <span class="hlt">pressure</span> <span class="hlt">gradient</span> force. The work is motivated by the desire to use an isentropic and sigma-coordinate hybrid model for experiments designed to study flow near mountainous terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870033194&hterms=coulomb+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcoulomb%2Blaw','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870033194&hterms=coulomb+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcoulomb%2Blaw"><span>Beam-induced <span class="hlt">pressure</span> <span class="hlt">gradients</span> in the early phase of proton-heated solar flares</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tamres, David H.; Canfield, Richard C.; Mcclymont, A. N.</p> <p>1986-01-01</p> <p>The <span class="hlt">pressure</span> <span class="hlt">gradient</span> induced in a coronal loop by proton beam momentum deposition is calculated and compared with the thermal <span class="hlt">pressure</span> <span class="hlt">gradient</span> arising from nonuniform deposition of beam energy; it is assumed that the transfer of momentum and energy from beam to target occurs via the Coulomb interaciton. Results are presented for both a low mean energy and a high mean energy proton beam injected at the loop apex and characterized by a power-law energy spectrum. The present treatment takes account of the breakdown of the cold target approximation for the low-energy proton beam in the corona, where the thermal speed of target electrons exceeds the beam speed. It is found that proton beam momentum deposition plays a potentially significant role in flare dynamics only in the low mean energy case and only in the corona, where it may dominate the acceleration of target material for as long as several tens of seconds. This conclusion suggest that the presence of low-energy nonthermal protons may be inferred from velocity-sensitive coronal observations in the early impulsive phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5316482','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5316482"><span>Broadening of Analyte Streams due to a Transverse <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> in Free-Flow Isoelectric Focusing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dutta, Debashis</p> <p>2017-01-01</p> <p><span class="hlt">Pressure</span>-driven cross-flows can arise in free-flow isoelectric focusing systems (FFIEF) due to a non-uniform electroosmotic flow velocity along the channel width induced by the pH <span class="hlt">gradient</span> 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 <span class="hlt">pressure-gradients</span> 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 due to transverse <span class="hlt">pressure-gradients</span> 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 flow 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 <span class="hlt">pressure</span>-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. PMID:28081900</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=gasoline&pg=4&id=EJ172477','ERIC'); return false;" href="https://eric.ed.gov/?q=gasoline&pg=4&id=EJ172477"><span>Tested Demonstrations. Gasoline <span class="hlt">Vapor</span>: An Invisible Pollutant</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Stephens, Edgar R.</p> <p>1977-01-01</p> <p>Describes a demonstration concerning the air pollution aspects of gasoline <span class="hlt">vapor</span> which provides an estimation of the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of test fuel, the molecular weight of the <span class="hlt">vapor</span>, and illustrates a method of controlling the pollution. (SL)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1236499-biophysical-controls-carbon-water-vapor-fluxes-across-grassland-climatic-gradient-united-states','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1236499-biophysical-controls-carbon-water-vapor-fluxes-across-grassland-climatic-gradient-united-states"><span>Biophysical controls on carbon and water <span class="hlt">vapor</span> fluxes across a grassland climatic <span class="hlt">gradient</span> in the United States</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Wagle, Pradeep; Xiao, Xiangming; Scott, Russell L.</p> <p></p> <p>Understanding of the underlying causes of spatial variation in exchange of carbon and water <span class="hlt">vapor</span> fluxes between grasslands and the atmosphere is crucial for accurate estimates of regional and global carbon and water budgets, and for predicting the impact of climate change on biosphere–atmosphere feedbacks of grasslands. We used ground-based eddy flux and meteorological data, and the Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI) from 12 grasslands across the United States to examine the spatial variability in carbon and water <span class="hlt">vapor</span> fluxes and to evaluate the biophysical controls on the spatial patterns of fluxes. Precipitation was strongly associatedmore » with spatial and temporal variability in carbon and water <span class="hlt">vapor</span> fluxes and vegetation productivity. Grasslands with annual average precipitation <600 mm generally had neutral annual carbon balance or emitted small amount of carbon to the atmosphere. Despite strong coupling between gross primary production (GPP)and evapotranspiration (ET) across study sites, GPP showed larger spatial variation than ET, and EVI had a greater effect on GPP than on ET. Consequently, large spatial variation in ecosystem water use efficiency (EWUE = annual GPP/ET; varying from 0.67 ± 0.55 to 2.52 ± 0.52 g C mm⁻¹ET) was observed. Greater reduction in GPP than ET at high air temperature and <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit caused a reduction in EWUE in dry years, indicating a response which is opposite than what has been reported for forests. Our results show that spatial and temporal variations in ecosystem carbon uptake, ET, and water use efficiency of grasslands were strongly associated with canopy greenness and coverage, as indicated by EVI.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800005954','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800005954"><span>Methods for calculation of engineering parameters for gas separation. [<span class="hlt">vapor</span> <span class="hlt">pressure</span> and solubility of gases in organic liquids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lawson, D. D.</p> <p>1979-01-01</p> <p>A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of <span class="hlt">vaporization</span> and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29267196','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29267196"><span>Zno Micro/Nanostructures Grown on Sapphire Substrates Using Low-Temperature <span class="hlt">Vapor</span>-Trapped Thermal Chemical <span class="hlt">Vapor</span> Deposition: Structural and Optical Properties.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Po-Sheng; Wu, Cheng-En; Chen, Guan-Lin</p> <p>2017-12-21</p> <p>In this research, the Zn(C₅H₇O₂)₂·xH₂O-based growth of ZnO micro/nanostructures in a low temperature, <span class="hlt">vapor</span>-trapped chemical <span class="hlt">vapor</span> deposition system was attempted to optimize structural and optical properties for potential biomedical applications. By trapping in-flow gas molecules and Zinc <span class="hlt">vapor</span> inside a chamber tube by partially obstructing a chamber outlet, a high <span class="hlt">pressure</span> condition can be achieved, and this experimental setup has the advantages of ease of synthesis, being a low temperature process, and cost effectiveness. Empirically, the growth process proceeded under a chamber condition of an atmospheric <span class="hlt">pressure</span> of 730 torr, a controlled volume flow rate of input gas, N₂/O₂, of 500/500 Standard Cubic Centimeters per Minute (SCCM), and a designated oven temperature of 500 °C. Specifically, the dependence of structural and optical properties of the structures on growth duration and spatially dependent temperature were investigated utilizing scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and ultraviolet-visible transmission spectroscopy. The experimental results indicate that the grown thin film observed with hexagonal structures and higher structural uniformity enables more prominent structural and optical signatures. XRD spectra present the dominant peaks along crystal planes of (002) and (101) as the main direction of crystallization. In addition, while the structures excited with laser wavelength of 325 nm emit a signature radiation around 380 nm, an ultraviolet lamp with a wavelength of 254 nm revealed distinctive photoluminescence peaks at 363.96 nm and 403.52 nm, elucidating different degrees of structural correlation as functions of growth duration and the spatial <span class="hlt">gradient</span> of temperature. Transmittance spectra of the structures illustrate typical variation in the wavelength range of 200 nm to 400 nm, and its structural correlation is less significant when compared with PL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5793501','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5793501"><span>Zno Micro/Nanostructures Grown on Sapphire Substrates Using Low-Temperature <span class="hlt">Vapor</span>-Trapped Thermal Chemical <span class="hlt">Vapor</span> Deposition: Structural and Optical Properties</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hu, Po-Sheng; Wu, Cheng-En; Chen, Guan-Lin</p> <p>2017-01-01</p> <p>In this research, the Zn(C5H7O2)2·xH2O-based growth of ZnO micro/nanostructures in a low temperature, <span class="hlt">vapor</span>-trapped chemical <span class="hlt">vapor</span> deposition system was attempted to optimize structural and optical properties for potential biomedical applications. By trapping in-flow gas molecules and Zinc <span class="hlt">vapor</span> inside a chamber tube by partially obstructing a chamber outlet, a high <span class="hlt">pressure</span> condition can be achieved, and this experimental setup has the advantages of ease of synthesis, being a low temperature process, and cost effectiveness. Empirically, the growth process proceeded under a chamber condition of an atmospheric <span class="hlt">pressure</span> of 730 torr, a controlled volume flow rate of input gas, N2/O2, of 500/500 Standard Cubic Centimeters per Minute (SCCM), and a designated oven temperature of 500 °C. Specifically, the dependence of structural and optical properties of the structures on growth duration and spatially dependent temperature were investigated utilizing scanning electron microscopy, X-ray diffraction (XRD), photoluminescence (PL), and ultraviolet-visible transmission spectroscopy. The experimental results indicate that the grown thin film observed with hexagonal structures and higher structural uniformity enables more prominent structural and optical signatures. XRD spectra present the dominant peaks along crystal planes of (002) and (101) as the main direction of crystallization. In addition, while the structures excited with laser wavelength of 325 nm emit a signature radiation around 380 nm, an ultraviolet lamp with a wavelength of 254 nm revealed distinctive photoluminescence peaks at 363.96 nm and 403.52 nm, elucidating different degrees of structural correlation as functions of growth duration and the spatial <span class="hlt">gradient</span> of temperature. Transmittance spectra of the structures illustrate typical variation in the wavelength range of 200 nm to 400 nm, and its structural correlation is less significant when compared with PL. PMID:29267196</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://hdl.handle.net/2060/19730006564','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730006564"><span>The turbulent boundary layer on a porous plate: An experimental study of the heat transfer behavior with adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blackwell, B. F.; Kays, W. M.; Moffat, R. J.</p> <p>1972-01-01</p> <p>An experimental investigation of the heat transfer behavior of the near equilibrium transpired turbulent boundary layer with adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> has been carried out. Stanton numbers were measured by an energy balance on electrically heated plates that form the bottom wall of the wind tunnel. Two adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> were studied. Two types of transpiration boundary conditions were investigated. The concept of an equilibrium thermal boundary layer was introduced. It was found that Stanton number as a function of enthalpy thickness Reynolds number is essentially unaffected by adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> with no transpiration. Shear stress, heat flux, and turbulent Prandtl number profiles were computed from mean temperature and velocity profiles. It was concluded that the turbulent Prandtl number is greater than unity in near the wall and decreases continuously to approximately 0.5 at the free stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24787565','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24787565"><span>Analysis of the intraocular jet flows and <span class="hlt">pressure</span> <span class="hlt">gradients</span> induced by air and fluid infusion: mechanism of focal chorioretinal damage.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Yong Joon; Jo, Sungkil; Moon, Daruchi; Joo, Youngcheol; Choi, Kyung Seek</p> <p>2014-05-01</p> <p>To comprehend the mechanism of focal chorioretinal damage by analysis of the <span class="hlt">pressure</span> distribution and dynamic <span class="hlt">pressure</span> induced by infused air during fluid-air exchange. A precise simulation featuring a model eye and a fluid circuit was designed to analyze fluid-air exchange. The <span class="hlt">pressure</span> distribution, flow velocity, and dynamic <span class="hlt">pressure</span> induced by infusion of air into an air-filled eye were analyzed using an approach based on fluid dynamics. The size of the port and the infusion <span class="hlt">pressure</span> were varied during simulated iterations. We simulated infusion of an air-filled eye with balanced salt solution (BSS) to better understand the mechanism of chorioretinal damage induced by infused air. Infused air was projected straight toward a point on the retina contralateral to the infusion port (the "vulnerable point"). The highest <span class="hlt">pressure</span> was evident at the vulnerable point, and the lowest <span class="hlt">pressure</span> was recorded on most retinal areas. Simulations using greater infusion <span class="hlt">pressure</span> and a port of larger size were associated with elevations in dynamic <span class="hlt">pressure</span> and the <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The <span class="hlt">pressure</span> <span class="hlt">gradients</span> were 2.8 and 5.1 mm Hg, respectively, when infusion <span class="hlt">pressures</span> of 30 and 50 mm Hg were delivered through a 20-gauge port. The <span class="hlt">pressure</span> <span class="hlt">gradient</span> associated with BSS infusion was greater than that created by air, but lasted for only a moment. Our simulation explains the mechanism of focal chorioretinal damage in numerical terms. Infused air induces a prolonged increase in focal <span class="hlt">pressure</span> on the vulnerable point, and this may be responsible for visual field defects arising after fluid-air exchange. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..DFD.M7003H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..DFD.M7003H"><span>Zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> boundary layer at extreme Reynolds numbers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hultmark, Marcus; Vallikivi, Margit; Smits, Alexander</p> <p>2011-11-01</p> <p>Experiments were conducted in a zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> flat plate boundary layer using the Princeton/ONR High Reynolds number Test Facility (HRTF). The HRTF uses highly compressed air, up to 220 atmospheres, to produce Reynolds numbers up to Reθ =225,000 . This corresponds to a δ+ =65,000 which is one of the highest Reynolds numbers ever measured in a laboratory. When using <span class="hlt">pressure</span> to achieve high Reynolds numbers the size of the measurement probes become critical, thus the need for very small sensors is acute. The streamwise component of velocity was investigated using a nanoscale thermal anemometer (NSTAP) as well as a 200 μm pitot tube. The NSTAP has a spatial resolution as well as a temporal resolution one order of magnitude better than conventional measurement techniques. The data was compared to recent data from a high Reynolds number turbulent pipe flow and it was shown that the two flows are more similar than previous data suggests. Supported under NR Grant N00014-09-1-0263 (program manager Ron Joslin) and NSF Grant CBET-1064257(program manager Henning Winter).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/20999347-vertical-two-phase-flow-regimes-pressure-gradients-under-influence-sds-surfactant','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/20999347-vertical-two-phase-flow-regimes-pressure-gradients-under-influence-sds-surfactant"><span>Vertical two-phase flow regimes and <span class="hlt">pressure</span> <span class="hlt">gradients</span> under the influence of SDS surfactant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Duangprasert, Tanabordee; Sirivat, Anuvat; Siemanond, Kitipat</p> <p>2008-01-15</p> <p>Two-phase gas/liquid flows in vertical pipes have been systematically investigated. Water and SDS surfactant solutions at various concentrations were used as the working fluids. In particular, we focus our work on the influence of surfactant addition on the flow regimes, the corresponding <span class="hlt">pressure</span> <span class="hlt">gradients</span>, and the bubble sizes and velocity. Adding the surfactant lowers the air critical Reynolds numbers for the bubble-slug flow and the slug flow transitions. The <span class="hlt">pressure</span> <span class="hlt">gradients</span> of SDS solutions are lower than those of pure water especially in the slug flow and the slug-churn flow regimes, implying turbulent drag reduction. At low Re{sub air}, themore » bubble sizes of the surfactant solution are lower than those of pure water due to the increase in viscosity. With increasing and at high Re{sub air}, the bubble sizes of the SDS solution become greater than those of pure water which is attributed to the effect of surface tension. (author)« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25105222','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25105222"><span>Correlation of chemical evaporation rate with <span class="hlt">vapor</span> <span class="hlt">pressure</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mackay, Donald; van Wesenbeeck, Ian</p> <p>2014-09-02</p> <p>A new one-parameter correlation is developed for the evaporation rate (ER) of chemicals as a function of molar mass (M) and <span class="hlt">vapor</span> <span class="hlt">pressure</span> (P) that is simpler than existing correlations. It applies only to liquid surfaces that are unaffected by the underlying solid substrate as occurs in the standard ASTM evaporation rate test and to quiescent liquid pools. The relationship has a sounder theoretical basis than previous correlations because ER is correctly correlated with PM rather than P alone. The inclusion of M increases the slope of previous log ER versus log P regressions to a value close to 1.0 and yields a simpler one-parameter correlation, namely, ER (μg m(-1) h(-1)) = 1464P (Pa) × M (g mol(-1)). Applications are discussed for the screening level assessment and ranking of chemicals for evaporation rate, such as pesticides, fumigants, and hydrocarbon carrier fluids used in pesticide formulations, liquid consumer products used indoors, and accidental spills of liquids. The mechanistic significance of the single parameter as a mass-transfer coefficient or velocity is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=62302&Lab=NERL&keyword=Engineering+AND+Mechanics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=62302&Lab=NERL&keyword=Engineering+AND+Mechanics&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>COMPUTATIONAL CHEMISTRY METHOD FOR PREDICTING <span class="hlt">VAPOR</span> <span class="hlt">PRESSURES</span> AND ACTIVITY COEFFICIENTS OF POLAR ORGANIC OXYGENATES IN PM2.5</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Parameterizations of interactions of polar multifunctional organic oxygenates in PM2.5 must be included in aerosol chemistry models for evaluating control strategies for reducing ambient concentrations of PM2.5 compounds. <span class="hlt">Vapor</span> <span class="hlt">pressures</span> and activity coefficients of these compo...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24209296','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24209296"><span>Fast <span class="hlt">gradient</span> separation by very high <span class="hlt">pressure</span> liquid chromatography: reproducibility of analytical data and influence of delay between successive runs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stankovicha, Joseph J; Gritti, Fabrice; Beaver, Lois Ann; Stevensona, Paul G; Guiochon, Georges</p> <p>2013-11-29</p> <p>Five methods were used to implement fast <span class="hlt">gradient</span> separations: constant flow rate, constant column-wall temperature, constant inlet <span class="hlt">pressure</span> at moderate and high <span class="hlt">pressures</span> (controlled by a <span class="hlt">pressure</span> controller),and programmed flow constant <span class="hlt">pressure</span>. For programmed flow constant <span class="hlt">pressure</span>, the flow rates and <span class="hlt">gradient</span> compositions are controlled using input into the method instead of the <span class="hlt">pressure</span> controller. Minor fluctuations in the inlet <span class="hlt">pressure</span> do not affect the mobile phase flow rate in programmed flow. There producibilities of the retention times, the response factors, and the eluted band width of six successive separations of the same sample (9 components) were measured with different equilibration times between 0 and 15 min. The influence of the length of the equilibration time on these reproducibilities is discussed. The results show that the average column temperature may increase from one separation to the next and that this contributes to fluctuation of the results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ApPhB..87..169R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ApPhB..87..169R"><span>Measurements of near-IR water <span class="hlt">vapor</span> absorption at high <span class="hlt">pressure</span> and temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rieker, G. B.; Liu, X.; Li, H.; Jeffries, J. B.; Hanson, R. K.</p> <p>2007-03-01</p> <p>Tunable diode lasers (TDLs) are used to measure high resolution (0.1 cm-1), near-infrared (NIR) water <span class="hlt">vapor</span> absorption spectra at 700 K and <span class="hlt">pressures</span> up to 30 atm within a high-<span class="hlt">pressure</span> and -temperature optical cell in a high-uniformity tube furnace. Both direct absorption and wavelength modulation with second harmonic detection (WMS-2f) spectra are obtained for 6 cm-1 regions near 7204 cm-1 and 7435 cm-1. Direct absorption measurements at 700 K and 10 atm are compared with simulations using spectral parameters from HITRAN and a hybrid database combining HITRAN with measured spectral constants for transitions in the two target spectral regions. The hybrid database reduces RMS error between the simulation and the measurements by 45% for the 7204 cm-1 region and 28% for the 7435 cm-1 region. At <span class="hlt">pressures</span> above 10 atm, the breakdown of the impact approximation inherent to the Lorentzian line shape model becomes apparent in the direct absorption spectra, and measured results are in agreement with model results and trends at elevated temperatures reported in the literature. The wavelength-modulation spectra are shown to be less affected by the breakdown of the impact approximation and measurements agree well with the hybrid database predictions to higher <span class="hlt">pressures</span> (30 atm).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850010726','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850010726"><span><span class="hlt">Vapor</span> <span class="hlt">pressure</span> and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bolgar, A. S.; Verkhoglyadova, T. S.; Samsonov, G. V.</p> <p>1985-01-01</p> <p>The <span class="hlt">vapor</span> <span class="hlt">pressure</span> and evaporation rate of borides of titanium, zirconium, and chrome; and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide; and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACP....13.1039M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACP....13.1039M"><span>Where do winds come from? A new theory on how water <span class="hlt">vapor</span> condensation influences atmospheric <span class="hlt">pressure</span> and dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Makarieva, A. M.; Gorshkov, V. G.; Sheil, D.; Nobre, A. D.; Li, B.-L.</p> <p>2013-01-01</p> <p>Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric <span class="hlt">pressure</span> through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air <span class="hlt">pressure</span> in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal <span class="hlt">pressure</span> differences associated with water <span class="hlt">vapor</span> condensation and find that these are comparable in magnitude with the <span class="hlt">pressure</span> differences driving observed circulation patterns. The water <span class="hlt">vapor</span> delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power - this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040087555&hterms=Gradient&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DGradient','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040087555&hterms=Gradient&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DGradient"><span>Improvement in diastolic intraventricular <span class="hlt">pressure</span> <span class="hlt">gradients</span> in patients with HOCM after ethanol septal reduction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rovner, Aleksandr; Smith, Rebecca; Greenberg, Neil L.; Tuzcu, E. Murat; Smedira, Nicholas; Lever, Harry M.; Thomas, James D.; Garcia, Mario J.</p> <p>2003-01-01</p> <p>We sought to validate measurement of intraventricular <span class="hlt">pressure</span> <span class="hlt">gradients</span> (IVPG) and analyze their change in patients with hypertrophic obstructive cardiomyopathy (HOCM) after ethanol septal reduction (ESR). Quantitative analysis of color M-mode Doppler (CMM) images may be used to estimate diastolic IVPG noninvasively. Noninvasive IVPG measurement was validated in 10 patients undergoing surgical myectomy. Echocardiograms were then analyzed in 19 patients at baseline and after ESR. Pulsed Doppler data through the mitral valve and pulmonary venous flow were obtained. CMM was used to obtain the flow propagation velocity (Vp) and to calculate IVPG off-line. Left atrial <span class="hlt">pressure</span> was estimated with the use of previously validated Doppler equations. Data were compared before and after ESR. CMM-derived IVPG correlated well with invasive measurements obtained before and after surgical myectomy [r = 0.8, P < 0.01, Delta(CMM - invasive IVPG) = 0.09 +/- 0.45 mmHg]. ESR resulted in a decrease of resting LVOT systolic <span class="hlt">gradient</span> from 62 +/- 10 to 29 +/- 5 mmHg (P < 0.001). There was a significant increase in the Vp and IVPG (from 48 +/- 5to 74 +/- 7 cm/s and from 1.5 +/- 0.2 to 2.6 +/- 0.3 mmHg, respectively, P < 0.001 for both). Estimated left atrial <span class="hlt">pressure</span> decreased from 16.2 +/- 1.1 to 11.5 +/- 0.9 mmHg (P < 0.001). The increase in IVPG correlated with the reduction in the LVOT <span class="hlt">gradient</span> (r = 0.6, P < 0.01). Reduction of LVOT obstruction after ESR is associated with an improvement in diastolic suction force. Noninvasive measurements of IVPG may be used as an indicator of diastolic function improvement in HOCM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22493773-analysis-organic-vapors-laser-induced-breakdown-spectroscopy','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22493773-analysis-organic-vapors-laser-induced-breakdown-spectroscopy"><span>Analysis of organic <span class="hlt">vapors</span> with laser induced breakdown spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Nozari, Hadi; Tavassoli, Seyed Hassan; Rezaei, Fatemeh, E-mail: fatemehrezaei@kntu.ac.ir</p> <p>2015-09-15</p> <p>In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane <span class="hlt">vapors</span>. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic <span class="hlt">vapors</span> that are mixed with air inside a quartz chamber at atmospheric <span class="hlt">pressure</span>. The plasma is generated with focused, Q-switched Nd:YAG radiation at the wavelength of 1064 nm. The effects of ignition and <span class="hlt">vapor</span> <span class="hlt">pressure</span> are discussed in view of the appearance of the emission spectra. The recorded spectra are proportional to the <span class="hlt">vapor</span> <span class="hlt">pressure</span> in air. The hydrogen and oxygen contributions diminishmore » gradually with consecutive laser-plasma events without gas flow. The results show that LIBS can be used to characterize organic <span class="hlt">vapor</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1418307-low-pressure-vapor-assisted-solution-process-tunable-band-gap-pinhole-free-methylammonium-lead-halide-perovskite-films','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1418307-low-pressure-vapor-assisted-solution-process-tunable-band-gap-pinhole-free-methylammonium-lead-halide-perovskite-films"><span>Low <span class="hlt">Pressure</span> <span class="hlt">Vapor</span>-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Sutter-Fella, Carolin M.; Li, Yanbo; Cefarin, Nicola</p> <p></p> <p>Organo-lead halide perovskites have recently attracted great interest for potential applications in thin-film photovoltaics and optoelectronics. Herein, we present a protocol for the fabrication of this material via the low-<span class="hlt">pressure</span> <span class="hlt">vapor</span> assisted solution process (LP-VASP) method, which yields ~19% power conversion efficiency in planar heterojunction perovskite solar cells. First, we report the synthesis of methylammonium iodide (CH 3NH 3I) and methylammonium bromide (CH 3NH 3Br) from methylamine and the corresponding halide acid (HI or HBr). Then, we describe the fabrication of pinhole-free, continuous methylammonium-lead halide perovskite (CH 3NH 3PbX 3 with X = I, Br, Cl and their mixture) filmsmore » with the LP-VASP. This process is based on two steps: i) spin-coating of a homogenous layer of lead halide precursor onto a substrate, and ii) conversion of this layer to CH 3NH 3PbI 3-xBr x by exposing the substrate to <span class="hlt">vapors</span> of a mixture of CH 3NH 3I and CH 3NH 3Br at reduced <span class="hlt">pressure</span> and 120 °C. Through slow diffusion of the methylammonium halide <span class="hlt">vapor</span> into the lead halide precursor, we achieve slow and controlled growth of a continuous, pinhole-free perovskite film. The LP-VASP allows synthetic access to the full halide composition space in CH 3NH 3PbI 3-xBr x with 0 ≤ x ≤ 3. Depending on the composition of the <span class="hlt">vapor</span> phase, the bandgap can be tuned between 1.6 eV ≤ E g ≤ 2.3 eV. In addition, by varying the composition of the halide precursor and of the <span class="hlt">vapor</span> phase, we can also obtain CH 3NH 3PbI 3-xCl x. Films obtained from the LP-VASP are reproducible, phase pure as confirmed by X-ray diffraction measurements, and show high photoluminescence quantum yield. The process does not require the use of a glovebox.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1418307-low-pressure-vapor-assisted-solution-process-tunable-band-gap-pinhole-free-methylammonium-lead-halide-perovskite-films','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1418307-low-pressure-vapor-assisted-solution-process-tunable-band-gap-pinhole-free-methylammonium-lead-halide-perovskite-films"><span>Low <span class="hlt">Pressure</span> <span class="hlt">Vapor</span>-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Sutter-Fella, Carolin M.; Li, Yanbo; Cefarin, Nicola; ...</p> <p>2017-09-08</p> <p>Organo-lead halide perovskites have recently attracted great interest for potential applications in thin-film photovoltaics and optoelectronics. Herein, we present a protocol for the fabrication of this material via the low-<span class="hlt">pressure</span> <span class="hlt">vapor</span> assisted solution process (LP-VASP) method, which yields ~19% power conversion efficiency in planar heterojunction perovskite solar cells. First, we report the synthesis of methylammonium iodide (CH 3NH 3I) and methylammonium bromide (CH 3NH 3Br) from methylamine and the corresponding halide acid (HI or HBr). Then, we describe the fabrication of pinhole-free, continuous methylammonium-lead halide perovskite (CH 3NH 3PbX 3 with X = I, Br, Cl and their mixture) filmsmore » with the LP-VASP. This process is based on two steps: i) spin-coating of a homogenous layer of lead halide precursor onto a substrate, and ii) conversion of this layer to CH 3NH 3PbI 3-xBr x by exposing the substrate to <span class="hlt">vapors</span> of a mixture of CH 3NH 3I and CH 3NH 3Br at reduced <span class="hlt">pressure</span> and 120 °C. Through slow diffusion of the methylammonium halide <span class="hlt">vapor</span> into the lead halide precursor, we achieve slow and controlled growth of a continuous, pinhole-free perovskite film. The LP-VASP allows synthetic access to the full halide composition space in CH 3NH 3PbI 3-xBr x with 0 ≤ x ≤ 3. Depending on the composition of the <span class="hlt">vapor</span> phase, the bandgap can be tuned between 1.6 eV ≤ E g ≤ 2.3 eV. In addition, by varying the composition of the halide precursor and of the <span class="hlt">vapor</span> phase, we can also obtain CH 3NH 3PbI 3-xCl x. Films obtained from the LP-VASP are reproducible, phase pure as confirmed by X-ray diffraction measurements, and show high photoluminescence quantum yield. The process does not require the use of a glovebox.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810012482','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810012482"><span>The influence of a high <span class="hlt">pressure</span> <span class="hlt">gradient</span> on unsteady velocity perturbations in the case of a turbulent supersonic flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dussauge, J. P.; Debieve, J. F.</p> <p>1980-01-01</p> <p>The amplification or reduction of unsteady velocity perturbations under the influence of strong flow acceleration or deceleration was studied. Supersonic flows with large velocity, <span class="hlt">pressure</span> <span class="hlt">gradients</span>, and the conditions in which the velocity fluctuations depend on the action of the average <span class="hlt">gradients</span> of <span class="hlt">pressure</span> and velocity rather than turbulence, are described. Results are analyzed statistically and interpreted as a return to laminar process. It is shown that this return to laminar implies negative values in the turbulence production terms for kinetic energy. A simple geometrical representation of the Reynolds stress production is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020020177','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020020177"><span>The Annual Cycle of Water <span class="hlt">Vapor</span> on Mars as Observed by the Thermal Emission Spectrometer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)</p> <p>2001-01-01</p> <p>Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water <span class="hlt">vapor</span> for over one full Martian year (March 1999-March 2001). A maximum in water <span class="hlt">vapor</span> abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water <span class="hlt">vapor</span> abundance (<5 pr-micrometer) is observed at middle and high latitudes in the fall and winter of both hemispheres. There are large differences in the hemispheric (north versus south) and seasonal (perihelion versus aphelion) behavior of water <span class="hlt">vapor</span>. The latitudinal and seasonal dependence of the decay of the northern summer water <span class="hlt">vapor</span> maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water <span class="hlt">vapor</span> (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface <span class="hlt">pressure</span>. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal <span class="hlt">gradient</span> in annually-averaged water <span class="hlt">vapor</span> observed by MAWD does not appear in the TES results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030111832','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030111832"><span>Alumina Volatility in Water <span class="hlt">Vapor</span> at Elevated Temperatures: Application to Combustion Environments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Opila, Elizabeth J.; Myers, Dwight L.</p> <p>2003-01-01</p> <p>The volatility of alumina in high temperature water <span class="hlt">vapor</span> was determined by measuring weight loss of sapphire coupons at temperatures between 1250 and 1500 C, water <span class="hlt">vapor</span> partial <span class="hlt">pressures</span> between 0.15 and 0.68 atm in oxygen, at one atmosphere total <span class="hlt">pressure</span>, and a gas velocity of 4.4 centimeters per second. The variation of the volatility with water <span class="hlt">vapor</span> partial <span class="hlt">pressure</span> was consistent with Al(OH)3(g) formation. The enthalpy of reaction to form Al(OH)3(g) from alumina and water <span class="hlt">vapor</span> was found to be 210 plus or minus 20 kJ/mol. Surface rearrangement of ground sapphire surfaces increased with water <span class="hlt">vapor</span> partial <span class="hlt">pressure</span>, temperature and volatility rate. Recession rates of alumina due to volatility were determined as a function of water <span class="hlt">vapor</span> partial <span class="hlt">pressure</span> and temperature to evaluate limits for use of alumina in long term applications in combustion environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMGC34A..06E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMGC34A..06E"><span>Use of Plant Hydraulic Theory to Predict Ecosystem Fluxes Across Mountainous <span class="hlt">Gradients</span> in Environmental Controls and Insect Disturbances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ewers, B. E.; Pendall, E.; Reed, D. E.; Barnard, H. R.; Whitehouse, F.; Frank, J. M.; Massman, W. J.; Brooks, P. D.; Biederman, J. A.; Harpold, A. A.; Naithani, K. J.; Mitra, B.; Mackay, D. S.; Norton, U.; Borkhuu, B.</p> <p>2011-12-01</p> <p>While mountainous areas are critical for providing numerous ecosystem benefits at the regional scale, the strong <span class="hlt">gradients</span> in environmental controls make predictions difficult. A key part of the problem is quantifying and predicting the feedback between mountain <span class="hlt">gradients</span> and plant function which then controls ecosystem cycling. The emerging theory of plant hydraulics provides a rigorous yet simple platform from which to generate testable hypotheses and predictions of ecosystem pools and fluxes. Plant hydraulic theory predicts that plant controls over carbon, water, energy and nutrient fluxes can be derived from the limitation of plant water transport from the soil through xylem and out of stomata. In addition, the limit to plant water transport can be predicted by combining plant structure (e.g. xylem diameters or root-to-shoot ratios) and plant function (response of stomatal conductance to <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit or root vulnerability to cavitation). We evaluate the predictions of the plant hydraulic theory by testing it against data from a mountain <span class="hlt">gradient</span> encompassing sagebrush steppe through subalpine forests (2700 to 3400 m). We further test the theory by predicting the carbon, water and nutrient exchanges from several coniferous trees in the same <span class="hlt">gradient</span> that are dying from xylem dysfunction caused by blue-stain fungi carried by bark beetles. The common theme of both of these data sets is a change in water limitation caused by either changing precipitation along the mountainous <span class="hlt">gradient</span> or lack of access to soil water from xylem-occluding fungi. Across all of the data sets which range in scale from individual plants to hillslopes, the data fit the predictions of plant hydraulic theory. Namely, there was a proportional tradeoff between the reference canopy stomatal conductance to water <span class="hlt">vapor</span> and the sensitivity of that conductance to <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit that quantitatively fits the predictions of plant hydraulic theory. Incorporating this result into</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27457561','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27457561"><span>Repeatability of <span class="hlt">gradient</span> ultrahigh <span class="hlt">pressure</span> liquid chromatography-tandem mass spectrometry methods in instrument-controlled thermal environments.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grinias, James P; Wong, Jenny-Marie T; Kennedy, Robert T</p> <p>2016-08-26</p> <p>The impact of viscous friction on eluent temperature and column efficiency in liquid chromatography is of renewed interest as the need for <span class="hlt">pressures</span> exceeding 1000bar to use with columns packed with sub-2μm particles has grown. One way the development of axial and radial temperature <span class="hlt">gradients</span> that arise due to viscous friction can be affected is by the thermal environment the column is placed in. In this study, a new column oven integrated into an ultrahigh <span class="hlt">pressure</span> liquid chromatograph that enables both still-air and forced-air operating modes is investigated to find the magnitude of the effect of the axial thermal <span class="hlt">gradient</span> that forms in 2.1×100mm columns packed with sub-2μm particles in these modes. Temperature increases of nearly 30K were observed when the generated power of the column exceeded 25W/m. The impact of the heating due to viscous friction on the repeatability of peak capacity, elution time, and peak area ratio to an internal standard for a <span class="hlt">gradient</span> UHPLC-MS/MS method to analyze neurotransmitters was found to be limited. This result indicates that high speed UHPLC-MS/MS <span class="hlt">gradient</span> methods under conditions of high viscous friction may be possible without the negative effects typically observed with isocratic separations under similar conditions. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940019623','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940019623"><span>Heat Pipe <span class="hlt">Vapor</span> Dynamics. Ph.D. Thesis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Issacci, Farrokh</p> <p>1990-01-01</p> <p>The dynamic behavior of the <span class="hlt">vapor</span> flow in heat pipes is investigated at startup and during operational transients. The <span class="hlt">vapor</span> is modeled as two-dimensional, compressible viscous flow in an enclosure with inflow and outflow boundary conditions. For steady-state and operating transients, the SIMPLER method is used. In this method a control volume approach is employed on a staggered grid which makes the scheme very stable. It is shown that for relatively low input heat fluxes the compressibility of the <span class="hlt">vapor</span> flow is low and the SIMPLER scheme is suitable for the study of transient <span class="hlt">vapor</span> dynamics. When the input heat flux is high or the process under a startup operation starts at very low <span class="hlt">pressures</span> and temperatures, the <span class="hlt">vapor</span> is highly compressible and a shock wave is created in the evaporator. It is shown that for a wide range of input heat fluxes, the standard methods, including the SIMPLER scheme, are not suitable. A nonlinear filtering technique, along with the centered difference scheme, are then used for shock capturing as well as for the solution of the cell Reynolds-number problem. For high heat flux, the startup transient phase involves multiple shock reflections in the evaporator region. Each shock reflection causes a significant increase in the local <span class="hlt">pressure</span> and a large <span class="hlt">pressure</span> drop along the heat pipe. Furthermore, shock reflections cause flow reversal in the evaporation region and flow circulations in the adiabatic region. The maximum and maximum-averaged <span class="hlt">pressure</span> drops in different sections of the heat pipe oscillate periodically with time because of multiple shock reflections. The <span class="hlt">pressure</span> drop converges to a constant value at steady state. However, it is significantly higher than its steady-state value at the initiation of the startup transient. The time for the <span class="hlt">vapor</span> core to reach steady-state condition depends on the input heat flux, the heat pipe geometry, the working fluid, and the condenser conditions. However, the <span class="hlt">vapor</span> transient time, for an Na</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('https://www.ncbi.nlm.nih.gov/pubmed/26257361','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26257361"><span>Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficits.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gong, Chunmei; Wang, Jiajia; Hu, Congxia; Wang, Junhui; Ning, Pengbo; Bai, Juan</p> <p>2015-08-01</p> <p>C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C4 species, regarding the interactive effects of drought stress and different leaf-air <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficits. Variables of interest included gas exchange, the activity levels of key C4 photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit than to strong water stress, and the net CO2 assimilation rate (An) was enhanced as <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficits increased. A close relationship between An and stomatal conductance (gs) suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C4 enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4 biochemical pathways were present in H. scoparium to respond to environmental challenges. Copyright © 2015. Published by Elsevier B.V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1251190-high-pressure-studies-using-two-stage-diamond-micro-anvils-grown-chemical-vapor-deposition','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1251190-high-pressure-studies-using-two-stage-diamond-micro-anvils-grown-chemical-vapor-deposition"><span>High <span class="hlt">pressure</span> studies using two-stage diamond micro-anvils grown by chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Vohra, Yogesh K.; Samudrala, Gopi K.; Moore, Samuel L.; ...</p> <p>2015-06-10</p> <p>Ultra-high static <span class="hlt">pressures</span> have been achieved in the laboratory using a two-stage micro-ball nanodiamond anvils as well as a two-stage micro-paired diamond anvils machined using a focused ion-beam system. The two-stage diamond anvils’ designs implemented thus far suffer from a limitation of one diamond anvil sliding past another anvil at extreme conditions. We describe a new method of fabricating two-stage diamond micro-anvils using a tungsten mask on a standard diamond anvil followed by microwave plasma chemical <span class="hlt">vapor</span> deposition (CVD) homoepitaxial diamond growth. A prototype two stage diamond anvil with 300 μm culet and with a CVD diamond second stage ofmore » 50 μm in diameter was fabricated. We have carried out preliminary high <span class="hlt">pressure</span> X-ray diffraction studies on a sample of rare-earth metal lutetium sample with a copper <span class="hlt">pressure</span> standard to 86 GPa. Furthermore, the micro-anvil grown by CVD remained intact during indentation of gasket as well as on decompression from the highest <span class="hlt">pressure</span> of 86 GPa.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16448061','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16448061"><span>Pseudolinear <span class="hlt">gradient</span> ultrahigh-<span class="hlt">pressure</span> liquid chromatography using an injection valve assembly.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiang, Yanqiao; Liu, Yansheng; Stearns, Stanley D; Plistil, Alex; Brisbin, Martin P; Lee, Milton L</p> <p>2006-02-01</p> <p>The use of ultrahigh <span class="hlt">pressures</span> in liquid chromatography (UHPLC) imposes stringent requirements on hardware such as pumps, valves, injectors, connecting tubing, and columns. One of the most difficult components of the UHPLC system to develop has been the sample injector. Static-split injection, which can be performed at <span class="hlt">pressures</span> up to 6900 bar (100,000 psi), consumes a large sample volume and is very irreproducible. A <span class="hlt">pressure</span>-balanced injection valve provided better reproducibility, shorter injection time, reduced sample consumption, and greater ease of use; however, it could only withstand <span class="hlt">pressures</span> up to approximately 1000 bar (15,000 psi). In this study, a new injection valve assembly that can operate at <span class="hlt">pressures</span> as high as 2070 bar (30,000 psi) was evaluated for UHPLC. This assembly contains six miniature electronically controlled needle valves to provide accurate and precise volumes for introduction into the capillary LC column. It was found that sample volumes as small as several tenths of a nanoliter can be injected, which are comparable to the results obtained from the static-split injector. The reproducibilities of retention time, efficiency, and peak area were investigated, and the results showed that the relative standard deviations of these parameters were small enough for quantitative analyses. Separation experiments using the UHPLC system with this new injection valve assembly showed that this new injector is suitable for both isocratic and <span class="hlt">gradient</span> operation modes. A newly designed capillary connector was used at a <span class="hlt">pressure</span> as high as 2070 bar (30,000 psi).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JAP....67.2264D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JAP....67.2264D"><span>Modeling and control of diffusion and low-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition furnaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Waard, H.; De Koning, W. L.</p> <p>1990-03-01</p> <p>In this paper a study is made of the heat transfer inside cylindrical resistance diffusion and low-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition furnaces, aimed at developing an improved temperature controller. A model of the thermal behavior is derived which also covers the important class of furnaces equipped with semitransparent quartz process tubes. The model takes into account the thermal behavior of the thermocouples. It is shown that currently used temperature controllers are highly inefficient for very large scale integration applications. Based on the model an alternative temperature controller of the linear-quadratic-Gaussian type is proposed which features direct wafer temperature control. Some simulation results are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930092247','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930092247"><span>Analysis and calculation by integral methods of laminar compressible boundary-layer with heat transfer and with and without <span class="hlt">pressure</span> <span class="hlt">gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morduchow, Morris</p> <p>1955-01-01</p> <p>A survey of integral methods in laminar-boundary-layer analysis is first given. A simple and sufficiently accurate method for practical purposes of calculating the properties (including stability) of the laminar compressible boundary layer in an axial <span class="hlt">pressure</span> <span class="hlt">gradient</span> with heat transfer at the wall is presented. For flow over a flat plate, the method is applicable for an arbitrarily prescribed distribution of temperature along the surface and for any given constant Prandtl number close to unity. For flow in a <span class="hlt">pressure</span> <span class="hlt">gradient</span>, the method is based on a Prandtl number of unity and a uniform wall temperature. A simple and accurate method of determining the separation point in a compressible flow with an adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> over a surface at a given uniform wall temperature is developed. The analysis is based on an extension of the Karman-Pohlhausen method to the momentum and the thermal energy equations in conjunction with fourth- and especially higher degree velocity and stagnation-enthalpy profiles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020044826&hterms=Beer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBeer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020044826&hterms=Beer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBeer"><span>Beer Law Constants and <span class="hlt">Vapor</span> <span class="hlt">Pressures</span> of HgI2 over HgI2(s,l)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.</p> <p>2002-01-01</p> <p>Optical absorption spectra of the <span class="hlt">vapor</span> phase over HgI2(s,l) were measured at sample temperatures between 349 and 610 K for wavelengths between 200 and 600 nm. The spectra show the samples sublimed congruently into HGI2 without any observed Hg or I2 absorption spectra. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were derived. From these constants the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of HgI2, P, was found to be a function of temperature for the liquid and the solid beta-phases: ln P(atm) = -7700/T(K) + 12.462 (liquid phase) and ln P(atm) = -10150/T(K) + 17.026 (beta-phase). The expressions match the enthalpies of <span class="hlt">vaporization</span> and sublimation of 15.30 and 20.17 kcal/mole respectively, for the liquid and the beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 kcal/mole, and the intersection of the two expressions gives a melting point of 537 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930092249','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930092249"><span>Characteristics of turbulence in boundary layer with zero <span class="hlt">pressure</span> <span class="hlt">gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Klebanoff, P S</p> <p>1955-01-01</p> <p>The results of an experimental investigation of a turbulent boundary layer with zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> are presented. Measurements with the hot-wire anemometer were made of turbulent energy and turbulent shear stress, probability density and flattening factor of u-fluctuation (fluctuation in x-direction), spectra of turbulent energy and shear stress, and turbulent dissipation. The importance of the region near the wall and the inadequacy of the concept of local isotropy are demonstrated. Attention is given to the energy balance and the intermittent character of the outer region of the boundary layer. Also several interesting features of the spectral distribution of the turbulent motions are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JNuM..294...69V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JNuM..294...69V"><span><span class="hlt">Vaporization</span> chemistry of hypo-stoichiometric (U,Pu)O 2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Viswanathan, R.; Krishnaiah, M. V.</p> <p>2001-04-01</p> <p>Calculations were performed on hypo-stoichiometric uranium plutonium di-oxide to examine its <span class="hlt">vaporization</span> behavior as a function of O/ M ( M= U+ Pu) ratio and plutonium content. The phase U (1- y) Pu yO z was treated as an ideal solid solution of (1- y)UO 2+ yPuO (2- x) such that x=(2- z)/ y. Oxygen potentials for different desired values of y, z, and temperature were used as the primary input to calculate the corresponding partial <span class="hlt">pressures</span> of various O-, U-, and Pu-bearing gaseous species. Relevant thermodynamic data for the solid phases UO 2 and PuO (2- x) , and the gaseous species were taken from the literature. Total <span class="hlt">vapor</span> <span class="hlt">pressure</span> varies with O/M and goes through a minimum. This minimum does not indicate a congruently <span class="hlt">vaporizing</span> composition. <span class="hlt">Vaporization</span> behavior of this system can at best be quasi-congruent. Two quasi-congruently <span class="hlt">vaporizing</span> compositions (QCVCs) exist, representing the equalities (O/M) <span class="hlt">vapor</span>=(O/M) mixed-oxide and (U/Pu) <span class="hlt">vapor</span>=(U/Pu) mixed-oxide, respectively. The (O/M) corresponding to QCVC1 is lower than that corresponding to QCVC2, but very close to the value where <span class="hlt">vapor</span> <span class="hlt">pressure</span> minimum occurs. The O/M values of both QCVCs increase with decrease in plutonium content. The <span class="hlt">vaporization</span> chemistry of this system, on continuous <span class="hlt">vaporization</span> under dynamic condition, is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.G51B0030C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.G51B0030C"><span>GPS Water <span class="hlt">Vapor</span> Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Champollion, C.; Masson, F.; Bock, O.; Bouin, M.; Walpersdorf, A.; Doerflinger, E.; van Baelen, J.; Brenot, H.</p> <p>2003-12-01</p> <p>The Global Positioning System (GPS) is now a common technique for the retrieval of zenithal integrated water <span class="hlt">vapor</span> (IWV). Further applications in meteorology need also slant integrated water <span class="hlt">vapor</span> (SIWV) which allow to precisely define the high variability of tropospheric water <span class="hlt">vapor</span> at different temporal and spatial scales. Only precise estimations of IWV and horizontal <span class="hlt">gradients</span> allow the estimation of accurate SIWV. We present studies developed to improve the estimation of tropospheric water <span class="hlt">vapor</span> from GPS data. Results are obtained from several field experiments (MAP, ESCOMPTE, OHM-CV, IHOP, .). First IWV are estimated using different GPS processing strategies and results are compared to radiosondes. The role of the reference frame and the a priori constraints on the coordinates of the fiducial and local stations is generally underestimated. It seems to be of first order in the estimation of the IWV. Second we validate the estimated horizontal <span class="hlt">gradients</span> comparing zenith delay <span class="hlt">gradients</span> and single site <span class="hlt">gradients</span>. IWV, <span class="hlt">gradients</span> and post-fit residuals are used to construct slant integrated water delays. Validation of the SIWV is under progress comparing GPS SIWV, Lidar measurements and high resolution meteorological models (Meso-NH). A careful analysis of the post-fit residuals is needed to separate tropospheric signal from multipaths. The slant tropospheric delays are used to study the 3D heterogeneity of the troposphere. We develop a tomographic software to model the three-dimensional distribution of the tropospheric water <span class="hlt">vapor</span> from GPS data. The software is applied to the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers operated in southern France. Three inversions have been successfully compared to three successive radiosonde launches. Good resolution is obtained up to heights of 3000 m.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950016141','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950016141"><span>Vacuum <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Poorman, Richard M. (Inventor); Weeks, Jack L. (Inventor)</p> <p>1995-01-01</p> <p>A method and apparatus is described for <span class="hlt">vapor</span> deposition of a thin metallic film utilizing an ionized gas arc directed onto a source material spaced from a substrate to be coated in a substantial vacuum while providing a <span class="hlt">pressure</span> differential between the source and the substrate so that, as a portion of the source is <span class="hlt">vaporized</span>, the <span class="hlt">vapors</span> are carried to the substrate. The apparatus includes a modified tungsten arc welding torch having a hollow electrode through which a gas, preferably inert, flows and an arc is struck between the electrode and the source. The torch, source, and substrate are confined within a chamber within which a vacuum is drawn. When the arc is struck, a portion of the source is <span class="hlt">vaporized</span> and the <span class="hlt">vapors</span> flow rapidly toward the substrate. A reflecting shield is positioned about the torch above the electrode and the source to ensure that the arc is struck between the electrode and the source at startup. The electrode and the source may be confined within a <span class="hlt">vapor</span> guide housing having a duct opening toward the substrate for directing the <span class="hlt">vapors</span> onto the substrate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104790&keyword=detector&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=104790&keyword=detector&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>DETERMINATION OF THE <span class="hlt">VAPOR</span> <span class="hlt">PRESSURES</span> OF SELECT POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS AT 75–275°C</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p><span class="hlt">Vapor</span> <span class="hlt">pressures</span> were determined for several polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at 75–275°C, extending the available literature data to more relevant temperature regions and providing the first experimental data for 2,3,7...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1050754-atmospheric-pressure-chemical-vapor-deposition-iron-pyrite-thin-films','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1050754-atmospheric-pressure-chemical-vapor-deposition-iron-pyrite-thin-films"><span>Atmospheric-<span class="hlt">Pressure</span> Chemical <span class="hlt">Vapor</span> Deposition of Iron Pyrite Thin Films</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Berry, Nicholas; Cheng, Ming; Perkins, Craig L.</p> <p>2012-10-23</p> <p>Iron pyrite (cubic FeS{sub 2}) is a promising candidate absorber material for earth-abundant thin-film solar cells. In this report, single-phase, large-grain, and uniform polycrystalline pyrite thin films are fabricated on glass and molybdenum-coated glass substrates by atmospheric-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition (AP-CVD) using the reaction of iron(III) acetylacetonate and tert-butyl disulfide in argon at 300 C, followed by sulfur annealing at 500--550 C to convert marcasite impurities to pyrite. The pyrite-marcasite phase composition depends strongly on the concentration of sodium in the growth substrate and the sulfur partial <span class="hlt">pressure</span> during annealing. Phase and elemental composition of the films are characterized bymore » X-ray diffraction, Raman spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, Rutherford backscattering spectrometry, and X-ray photoelectron spectroscopy. The in-plane electrical properties are surprisingly insensitive to phase and elemental impurities, with all films showing p-type, thermally activated transport with a small activation energy ({approx}30 meV), a room- temperature resistivity of {approx}1 {Omega} cm, and low mobility. These ubiquitous electrical properties may result from robust surface effects. These CVD pyrite thin films are well suited to fundamental electrical studies and the fabrication of pyrite photovoltaic device stacks.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PSST...27c5008Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PSST...27c5008Y"><span>Magnetical asymmetry effect in capacitively coupled plasmas: effects of the magnetic field <span class="hlt">gradient</span>, <span class="hlt">pressure</span>, and gap length</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Shali; Chang, Lijie; Zhang, Ya; Jiang, Wei</p> <p>2018-03-01</p> <p>By applying the asymmetric magnetic field to a discharge, the dc self-bias and asymmetric plasma response can be generated even in a geometrically and electrically symmetric system. This is called magnetical asymmetric effect (MAE), which can be a new method to control the ion energy and flux independently (Yang et al 2017 Plasma Process. Polym. 14 1700087). In the present work, the effects of magnetic field <span class="hlt">gradient</span>, gas <span class="hlt">pressure</span> and gap length on MAE are investigated by using a one-dimensional implicit particle-in-cell/Monte Carlo collision simulation. It found that by appropriately increasing the magnetic field <span class="hlt">gradient</span> and the gap length, the range of the self-bias voltage will be enlarged, which can be used as the effective approach to control the ion bombarding energy at the electrodes since the ion energy is determined by the voltage drop across the sheath. It also found that the ion flux asymmetry will disappear at high <span class="hlt">pressure</span> when the magnetic field <span class="hlt">gradient</span> is relative low, due to the frequent electron-neutral collisions can disrupt electron gyromotion and thus the MAE is greatly reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/fuels-registration-reporting-and-compliance-help/reid-vapor-pressure-rvp-gasoline-spreadsheet','PESTICIDES'); return false;" href="https://www.epa.gov/fuels-registration-reporting-and-compliance-help/reid-vapor-pressure-rvp-gasoline-spreadsheet"><span>Reid <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> (RVP) of Gasoline Spreadsheet Example Key for Requirements at 40 CFR 80.47(g) and 80.47(l)</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>This guidance deals with the self-qualification of analytical test methods at a testing facility for measuring Reid <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> (RVP) of gasoline to meet precision requirements codified in regulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JTST...19..502V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JTST...19..502V"><span><span class="hlt">Vapor</span> Phase Deposition Using Plasma Spray-PVD™</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>von Niessen, K.; Gindrat, M.; Refke, A.</p> <p>2010-01-01</p> <p>Plasma spray—physical <span class="hlt">vapor</span> deposition (PS-PVD) is a low <span class="hlt">pressure</span> plasma spray technology to deposit coatings out of the <span class="hlt">vapor</span> phase. PS-PVD is a part of the family of new hybrid processes recently developed by Sulzer Metco AG (Switzerland) on the basis of the well-established low <span class="hlt">pressure</span> plasma spraying (LPPS) technology. Included in this new process family are plasma spray—chemical <span class="hlt">vapor</span> deposition (PS-CVD) and plasma spray—thin film (PS-TF) processes. In comparison to conventional vacuum plasma spraying and LPPS, these new processes use a high energy plasma gun operated at a work <span class="hlt">pressure</span> below 2 mbar. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An important new feature of PS-PVD is the possibility to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats, but also by <span class="hlt">vaporizing</span> the injected material. Therefore, the PS-PVD process fills the gap between the conventional PVD technologies and standard thermal spray processes. The possibility to <span class="hlt">vaporize</span> feedstock material and to produce layers out of the <span class="hlt">vapor</span> phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and EB-PVD coatings. This paper reports on the progress made at Sulzer Metco to develop functional coatings build up from <span class="hlt">vapor</span> phase of oxide ceramics and metals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19466810','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19466810"><span>Stability limit of liquid water in metastable equilibrium with subsaturated <span class="hlt">vapors</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wheeler, Tobias D; Stroock, Abraham D</p> <p>2009-07-07</p> <p>A pure liquid can reach metastable equilibrium with its subsaturated <span class="hlt">vapor</span> across an appropriate membrane. This situation is analogous to osmotic equilibrium: the reduced chemical potential of the dilute phase (the subsaturated <span class="hlt">vapor</span>) is compensated by a difference in <span class="hlt">pressure</span> between the phases. To equilibrate with subsaturated <span class="hlt">vapor</span>, the liquid phase assumes a <span class="hlt">pressure</span> that is lower than its standard <span class="hlt">vapor</span> <span class="hlt">pressure</span>, such that the liquid phase is metastable with respect to the <span class="hlt">vapor</span> phase. For sufficiently subsaturated <span class="hlt">vapors</span>, the liquid phase can even assume negative <span class="hlt">pressures</span>. The appropriate membrane for this metastable equilibrium must provide the necessary mechanical support to sustain the difference in <span class="hlt">pressure</span> between the two phases, limit nonhomogeneous mechanisms of cavitation, and resist the entry of the dilutant (gases) into the pure phase (liquid). In this article, we present a study of the limit of stability of liquid water--the degree of subsaturation at which the liquid cavitates--in this metastable state within microscale voids embedded in hydrogel membranes. We refer to these structures as <span class="hlt">vapor</span>-coupled voids (VCVs). In these VCVs, we observed that liquid water cavitated when placed in equilibrium with <span class="hlt">vapors</span> of activity aw,vapair<or=0.85 (relative humidity<or=85%). When expressed as a <span class="hlt">pressure</span> in the liquid based on thermodynamic calculations, the liquid cavitated at <span class="hlt">pressures</span> P<or=-22 MPa (-220 bar). This limiting <span class="hlt">pressure</span> is smaller in magnitude than the limit predicted by homogeneous nucleation theory or molecular simulations (Pcav=-140 to -180 MPa). To determine the cause of the disparity between the observed and predicted stability limit, we examine experimentally the likelihood of several nonhomogeneous mechanisms of nucleation: (i) heterogeneous nucleation caused by hydrophobic patches on void walls, (ii) nucleation caused by the presence of dissolved solute, (iii) nucleation caused by the presence of pre-existing <span class="hlt">vapor</span> nuclei, and (iv</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018RJPCA..92..407V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018RJPCA..92..407V"><span>Melt-<span class="hlt">Vapor</span> Phase Diagram of the Te-S System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Volodin, V. N.; Trebukhov, S. A.; Kenzhaliyev, B. K.; Nitsenko, A. V.; Burabaeva, N. M.</p> <p>2018-03-01</p> <p>The values of partial <span class="hlt">pressure</span> of saturated <span class="hlt">vapor</span> of the constituents of the Te-S system are determined from boiling points. The boundaries of the melt-<span class="hlt">vapor</span> phase transition at atmospheric <span class="hlt">pressure</span> and in vacuum of 2000 and 100 Pa are calculated on the basis of partial <span class="hlt">pressures</span>. A phase diagram that includes <span class="hlt">vapor</span>-liquid equilibrium fields whose boundaries allow us to assess the behavior of elements upon distillation fractioning is plotted. It is established that the separation of elements is possible at the first evaporation-condensation cycle. Complications can be caused by crystallization of a sulfur solid solution in tellurium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730015211','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730015211"><span>Net <span class="hlt">vapor</span> generation point in boiling flow of trichlorotrifluoroethane at high <span class="hlt">pressures</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dougall, R. S.; Lippert, T. E.</p> <p>1973-01-01</p> <p>The conditions at which the void in subcooled boiling starts to undergo a rapid increase were studied experimentally. The experiments were performed in a 12.7 x 9.5 mm rectangular channel. Heating was from a 3.2 mm wide strip embedded in one wall. The <span class="hlt">pressure</span> ranged from 9.45 to 20.7 bar, mass velocity from 600 to 7000 kg/sq m sec, and subcooling from 16 to 67 C. Photographs were used to determine when detached bubbles first appeared in the bulk flow. Measurements of bubble layer thickness along the wall were also made. Results showed that the point of net <span class="hlt">vapor</span> generation is close to the occurrence of fully-developed boiling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040112441&hterms=adrenergic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dadrenergic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040112441&hterms=adrenergic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dadrenergic"><span>Estimation of diastolic intraventricular <span class="hlt">pressure</span> <span class="hlt">gradients</span> by Doppler M-mode echocardiography</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Greenberg, N. L.; Vandervoort, P. M.; Firstenberg, M. S.; Garcia, M. J.; Thomas, J. D.</p> <p>2001-01-01</p> <p>Previous studies have shown that small intraventricular <span class="hlt">pressure</span> <span class="hlt">gradients</span> (IVPG) are important for efficient filling of the left ventricle (LV) and as a sensitive marker for ischemia. Unfortunately, there has previously been no way of measuring these noninvasively, severely limiting their research and clinical utility. Color Doppler M-mode (CMM) echocardiography provides a spatiotemporal velocity distribution along the inflow tract throughout diastole, which we hypothesized would allow direct estimation of IVPG by using the Euler equation. Digital CMM images, obtained simultaneously with intracardiac <span class="hlt">pressure</span> waveforms in six dogs, were processed by numerical differentiation for the Euler equation, then integrated to estimate IVPG and the total (left atrial to left ventricular apex) <span class="hlt">pressure</span> drop. CMM-derived estimates agreed well with invasive measurements (IVPG: y = 0.87x + 0.22, r = 0.96, P < 0.001, standard error of the estimate = 0.35 mmHg). Quantitative processing of CMM data allows accurate estimation of IVPG and tracking of changes induced by beta-adrenergic stimulation. This novel approach provides unique information on LV filling dynamics in an entirely noninvasive way that has previously not been available for assessment of diastolic filling and function.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=biodiesel&pg=2&id=EJ923698','ERIC'); return false;" href="https://eric.ed.gov/?q=biodiesel&pg=2&id=EJ923698"><span>An Integrated Approach to Introducing Biofuels, Flash Point, and <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> Concepts into an Introductory College Chemistry Lab</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Hoffman, Adam R.; Britton, Stephanie L.; Cadwell, Katie D.; Walz, Kenneth A.</p> <p>2011-01-01</p> <p>Students explore the fundamental chemical concepts of <span class="hlt">vapor</span> <span class="hlt">pressure</span> and flash point in a real-world technical context, while gaining insight into the contemporary societal issue of biofuels. Lab activities were developed using a closed-cup instrument to measure the flash point of various biodiesel samples. Pre- and post-tests revealed that the…</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://hdl.handle.net/2060/19960007439','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960007439"><span>The control of purity and stoichiometry of compound semiconductors by high <span class="hlt">vapor</span> <span class="hlt">pressure</span> transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bachmann, Klaus J.; Ito, Kazufumi; Scroggs, Jeffery S.; Tran, Hien T.</p> <p>1995-01-01</p> <p>In this report we summarize the results of a three year research program on high <span class="hlt">pressure</span> <span class="hlt">vapor</span> transport (HPVT) of compound semiconductors. Most of our work focused onto pnictides, in particular ZnGeP2, as a model system. Access to single crystals of well controlled composition of this material is desired for advancing the understanding and control of its point defect chemistry in the contest of remote, real-time sensing of trace impurities, e.g., greenhouse gases, in the atmosphere by ZnGeP2 optical parametric oscillators (OPO's).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930019505','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930019505"><span>Preliminary endurance tests of water <span class="hlt">vaporizers</span> for resistojet applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morren, W. Earl; Macrae, Gregory S.</p> <p>1993-01-01</p> <p>Three water <span class="hlt">vaporizers</span> designed for resistojet applications were built and tested for periods up to 500 h and 250 thermal cycles. Two of the <span class="hlt">vaporizers</span> were not sensitive to orientation with respect to gravity, an indication of likely compatibility with low-gravity environments. Some temperatures and <span class="hlt">pressures</span> in the third were impacted by orientation, although operation was always stable. The <span class="hlt">pressure</span> drop across the sand-filled version increased by 147 percent in 38 h and 19 thermal cycles. Bonding of the sand granules in the downstream end of the heat exchanger was the suspected cause of failure of this <span class="hlt">vaporizer</span>. <span class="hlt">Pressure</span> drops across the two sintered stainless steel-filled versions were more gradual. One, with a pore size of 60 microns, showed an 80 percent increase in 500 h and 250 thermal cycles and another, with a 10 microns poresize, showed a 29 percent increase in 350 h and 175 thermal cycles. Testing of the latter metal-filled <span class="hlt">vaporizer</span> was ongoing as of this writing. Oxidation of the porous metal packing materials in these <span class="hlt">vaporizers</span>, with subsequent deposition of oxide particles within the pores, was believed to have caused the observed increases in <span class="hlt">pressure</span> drops.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985asme.confU....M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985asme.confU....M"><span>The influence of the radial <span class="hlt">pressure</span> <span class="hlt">gradient</span> on the blade root loss in an annular subsonic nozzle cascade</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meng, D.; Weng, Z.; Xiang, Y.</p> <p>1985-09-01</p> <p>This paper presents a method for predicting the blade root loss in an annular nozzle cascade in which consideration is given to the influence of the radial <span class="hlt">pressure</span> <span class="hlt">gradient</span> (RPG) on it. The variation of blade root losses under different RPG is obtained experimentally, and finite element method is used to calculate the <span class="hlt">pressure</span> distribution in the blade passage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1015232','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1015232"><span>Effect of Water <span class="hlt">Vapor</span> <span class="hlt">Pressure</span> on Fatigue Crack Growth in Al-Zn-Cu-Mg Alloy Over Wide-Range Stress Intensity Factor Loading</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-05-07</p> <p>impacts: (a) crack closure, (b) transport of water <span class="hlt">vapor</span> molecules within the fatigue crack (47], and (c) tensile stress-plastic strain range...sealed stainless steel UHV chamber. Pure water <span class="hlt">vapor</span> was introduced from a sealed glass flask containing triply distilled water, via a precision leak...lamellar for H1 flow in a fatigue crack in steel ; specifically, flow is dominated by the low dynamic viscosity of a gas (particularly at low <span class="hlt">pressures</span>) and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JASMS..28..263S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JASMS..28..263S"><span>Use of Interrupted Helium Flow in the Analysis of <span class="hlt">Vapor</span> Samples with Flowing Atmospheric-<span class="hlt">Pressure</span> Afterglow-Mass Spectrometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Storey, Andrew P.; Zeiri, Offer M.; Ray, Steven J.; Hieftje, Gary M.</p> <p>2017-02-01</p> <p>The flowing atmospheric-<span class="hlt">pressure</span> afterglow (FAPA) source was used for the mass-spectrometric analysis of <span class="hlt">vapor</span> samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level. This initial signal appears to be due to greater interaction of sample <span class="hlt">vapor</span> with the afterglow of the source when helium flow resumes. In part, the initial spike in signal can be attributed to a pooling of analyte <span class="hlt">vapor</span> in the absence of helium flow from the source. Time-resolved schlieren imaging of the helium flow during on and off cycles provided insight into gas-flow patterns between the FAPA source and the MS inlet that were correlated with mass-spectral data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27757823','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27757823"><span>Use of Interrupted Helium Flow in the Analysis of <span class="hlt">Vapor</span> Samples with Flowing Atmospheric-<span class="hlt">Pressure</span> Afterglow-Mass Spectrometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Storey, Andrew P; Zeiri, Offer M; Ray, Steven J; Hieftje, Gary M</p> <p>2017-02-01</p> <p>The flowing atmospheric-<span class="hlt">pressure</span> afterglow (FAPA) source was used for the mass-spectrometric analysis of <span class="hlt">vapor</span> samples introduced between the source and mass spectrometer inlet. Through interrupted operation of the plasma-supporting helium flow, helium consumption is greatly reduced and dynamic gas behavior occurs that was characterized by schlieren imaging. Moreover, mass spectra acquired immediately after the onset of helium flow exhibit a signal spike before declining and ultimately reaching a steady level. This initial signal appears to be due to greater interaction of sample <span class="hlt">vapor</span> with the afterglow of the source when helium flow resumes. In part, the initial spike in signal can be attributed to a pooling of analyte <span class="hlt">vapor</span> in the absence of helium flow from the source. Time-resolved schlieren imaging of the helium flow during on and off cycles provided insight into gas-flow patterns between the FAPA source and the MS inlet that were correlated with mass-spectral data. Graphical Abstract ᅟ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010018435','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010018435"><span>Measurement of the Turbulence Kinetic Energy Budget of a Turbulent Planar Wake Flow in <span class="hlt">Pressure</span> <span class="hlt">Gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, Xiao-Feng; Thomas, Flint O.; Nelson, Robert C.</p> <p>2001-01-01</p> <p>Turbulence kinetic energy (TKE) is a very important quantity for turbulence modeling and the budget of this quantity in its transport equation can provide insight into the flow physics. Turbulence kinetic energy budget measurements were conducted for a symmetric turbulent wake flow subjected to constant zero, favorable and adverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> in year-three of research effort. The purpose of this study is to clarify the flow physics issues underlying the demonstrated influence of <span class="hlt">pressure</span> <span class="hlt">gradient</span> on wake development and provide experimental support for turbulence modeling. To ensure the reliability of these notoriously difficult measurements, the experimental procedure was carefully designed on the basis of an uncertainty analysis. Four different approaches, based on an isotropic turbulence assumption, a locally axisymmetric homogeneous turbulence assumption, a semi-isotropy assumption and a forced balance of the TKE equation, were applied for the estimate of the dissipation term. The <span class="hlt">pressure</span> transport term is obtained from a forced balance of the turbulence kinetic energy equation. This report will present the results of the turbulence kinetic energy budget measurement and discuss their implication on the development of strained turbulent wakes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750006922','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750006922"><span>An experimental investigation of heat transfer to reusable surface insulation tile array gaps in a turbulent boundary layer with <span class="hlt">pressure</span> <span class="hlt">gradient</span>. M.S. Thesis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Throckmorton, D. A.</p> <p>1975-01-01</p> <p>An experimental investigation was performed to determine the effect of <span class="hlt">pressure</span> <span class="hlt">gradient</span> on the heat transfer to space shuttle reusable surface insulation (RSI) tile array gaps under thick, turbulent boundary layer conditions. Heat transfer and <span class="hlt">pressure</span> measurements were obtained on a curved array of full-scale simulated RSI tiles in a tunnel wall boundary layer at a nominal freestream Mach number of 10.3 and freestream unit Reynolds numbers of 1.6, 3.3, and and 6.1 million per meter. Transverse <span class="hlt">pressure</span> <span class="hlt">gradients</span> were induced over the model surface by rotating the curved array with respect to the flow. Definition of the tunnel wall boundary layer flow was obtained by measurement of boundary layer pitot <span class="hlt">pressure</span> profiles, and flat plate wall <span class="hlt">pressure</span> and heat transfer. Flat plate wall heat transfer data were correlated and a method was derived for prediction of smooth, curved array heat transfer in the highly three-dimensional tunnel wall boundary layer flow and simulation of full-scale space shuttle vehicle <span class="hlt">pressure</span> <span class="hlt">gradient</span> levels was assessed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23688025','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23688025"><span>Combinatorial atmospheric <span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition of graded TiO₂-VO₂ mixed-phase composites and their dual functional property as self-cleaning and photochromic window coatings.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilkinson, Mia; Kafizas, Andreas; Bawaked, Salem M; Obaid, Abdullah Y; Al-Thabaiti, Shaeel A; Basahel, Sulaiman N; Carmalt, Claire J; Parkin, Ivan P</p> <p>2013-06-10</p> <p>A combinatorial film with a phase <span class="hlt">gradient</span> from V:TiO₂ (V: Ti ≥ 0.08), through a range of TiO₂-VO₂ composites, to a vanadium-rich composite (V: Ti = 1.81) was grown by combinatorial atmospheric <span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition (cAPCVD). The film was grown from the reaction of TiCl₄, VCl₄, ethyl acetate (EtAc), and H₂O at 550 °C on glass. The <span class="hlt">gradient</span> in gas mixtures across the reactor induced compositional film growth, producing a single film with numerous phases and compositions at different positions. Seventeen unique positions distributed evenly along a central horizontal strip were investigated. The physical properties were characterized by wavelength dispersive X-ray (WDX) analysis, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and UV-visible spectroscopy. The functional properties examined included the degree of photoinduced hydrophilicity (PIH), UVC-photocatalysis, and thermochromism. Superhydrophilic contact angles could be achieved at all positions, even within a highly VO₂-rich composite (V: Ti = 1.81). A maximum level of UVC photocatalysis was observed at a position bordering the solubility limit of V:TiO₂ (V: Ti ≈ 0.21) and fragmentation into a mixed-phase composite. Within the mixed-phase TiO₂: VO₂ composition region (V: Ti = 1.09 to 1.81) a decrease in the semiconductor-to-metal transition temperature of VO₂ from 68 to 51 °C was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5850479','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5850479"><span>Effects of ambient temperature and water <span class="hlt">vapor</span> on chamber <span class="hlt">pressure</span> and oxygen level during low atmospheric <span class="hlt">pressure</span> stunning of poultry</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Holloway, Paul H.; Pritchard, David G.</p> <p>2017-01-01</p> <p>Abstract The characteristics of the vacuum used in a low atmospheric <span class="hlt">pressure</span> stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum <span class="hlt">pressure</span> is reduced from ambient atmospheric <span class="hlt">pressure</span> to an absolute vacuum <span class="hlt">pressure</span> of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing <span class="hlt">pressure</span>. Ambient temperature affects air density and water <span class="hlt">vapor</span> <span class="hlt">pressure</span> and thereby oxygen levels and the time at the minimum total <span class="hlt">pressure</span> of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total <span class="hlt">pressure</span> results in a gradual reduction of oxygen partial <span class="hlt">pressure</span> that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen <span class="hlt">pressure</span> leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (<span class="hlt">pressure</span> versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum <span class="hlt">pressure</span> rather than gauge <span class="hlt">pressure</span>. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the <span class="hlt">pressure</span>-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial <span class="hlt">pressure</span> of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. PMID</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900017458','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900017458"><span>Liquid-<span class="hlt">Vapor</span> Equilibrium of Multicomponent Cryogenic Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thompson, W. Reid; Calado, Jorge C. G.; Zollweg, John A.</p> <p>1990-01-01</p> <p>Liquid-<span class="hlt">vapor</span> and solid-<span class="hlt">vapor</span> equilibria at low to moderate <span class="hlt">pressures</span> and low temperatures are important in many solar system environments, including the surface and clouds of Titan, the clouds of Uranus and Neptune, and the surfaces of Mars and Triton. The familiar cases of ideal behavior are limiting cases of a general thermodynamic representation for the <span class="hlt">vapor</span> <span class="hlt">pressure</span> of each component in a homogeneous multicomponent system. The fundamental connections of laboratory measurements to thermodynamic models are through the Gibbs-Duhem relation and the Gibbs-Helmholtz relation. Using laboratory measurements of the total <span class="hlt">pressure</span>, temperature, and compositions of the liquid and <span class="hlt">vapor</span> phases at equilibrium, the values of these parameters can be determined. The resulting model for <span class="hlt">vapor</span>-liquid equilibrium can then conveniently and accurately be used to calculate <span class="hlt">pressures</span>, compositions, condensation altitudes, and their dependencies on changing climatic conditions. A specific system being investigated is CH4-C2H6-N2, at conditions relevant to Titan's surface and atmosphere. Discussed are: the modeling of existing data on CH4-N2, with applications to the composition of Titan's condensate clouds; some new measurements on the CH4-C2H6 binary, using a high-precision static/volumetric system, and on the C2H6-N2 binary, using the volumetric system and a sensitive cryogenic flow calorimeter; and describe a new cryogenic phase-equilibrium vessel with which we are beginning a detailed, systematic study of the three constituent binaries and the ternary CH4-C2H6-N2 system at temperatures ranging from 80 to 105 K and <span class="hlt">pressures</span> from 0.1 to 7 bar.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720007523','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720007523"><span>Calculation of turbulent boundary layers with heat transfer and <span class="hlt">pressure</span> <span class="hlt">gradient</span> utilizing a compressibility transformation. Part 3: Computer program manual</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schneider, J.; Boccio, J.</p> <p>1972-01-01</p> <p>A computer program is described capable of determining the properties of a compressible turbulent boundary layer with <span class="hlt">pressure</span> <span class="hlt">gradient</span> and heat transfer. The program treats the two-dimensional problem assuming perfect gas and Crocco integral energy solution. A compressibility transformation is applied to the equation for the conservation of mass and momentum, which relates this flow to a low speed constant property flow with simultaneous mass transfer and <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The resulting system of describing equations consists of eight ordinary differential equations which are solved numerically. For Part 1, see N72-12226; for Part 2, see N72-15264.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1261504-characterization-urania-vaporization-transpiration-coupled-thermogravimetry','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1261504-characterization-urania-vaporization-transpiration-coupled-thermogravimetry"><span>Characterization of urania <span class="hlt">vaporization</span> with transpiration coupled thermogravimetry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>McMurray, J. W.</p> <p>2015-12-05</p> <p>Determining equilibrium <span class="hlt">vapor</span> <span class="hlt">pressures</span> of materials is made easier by transpiration measurements. However, the traditional technique involves condensing the volatiles entrained in a carrier gas outside of the hot measurement zone. One potential problem is deposition en route to a cooled collector. Thermogravimetric analysis (TGA) can be used to measure in situ mass loss due to <span class="hlt">vaporization</span> and therefore obviate the need to analyze the entire gas train due to premature plating of <span class="hlt">vapor</span> species. Therefore, a transpiration coupled TGA technique was used to determine equilibrium <span class="hlt">pressures</span> of UO3 gas over fluorite structure UO2+x and U3O8 at T = (1573more » and 1773) K. Moreover, we compared to calculations from models and databases in the open literature. Our study gives clarity to the thermochemical data for UO3 gas and validates the mass loss transpiration method using thermogravimetry for determining equilibrium <span class="hlt">vapor</span> <span class="hlt">pressures</span> of non-stoichiometric oxides.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol3/pdf/CFR-2012-title40-vol3-sec52-787.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol3/pdf/CFR-2012-title40-vol3-sec52-787.pdf"><span>40 CFR 52.787 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2012-07-01</p> <p>... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer <span class="hlt">vapor</span> control. (a) Gasoline means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol3/pdf/CFR-2011-title40-vol3-sec52-787.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol3/pdf/CFR-2011-title40-vol3-sec52-787.pdf"><span>40 CFR 52.787 - Gasoline transfer <span class="hlt">vapor</span> control.</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>... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer <span class="hlt">vapor</span> control. (a) Gasoline means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol3/pdf/CFR-2013-title40-vol3-sec52-787.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol3/pdf/CFR-2013-title40-vol3-sec52-787.pdf"><span>40 CFR 52.787 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2013-07-01</p> <p>... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer <span class="hlt">vapor</span> control. (a) Gasoline means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol3/pdf/CFR-2010-title40-vol3-sec52-787.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol3/pdf/CFR-2010-title40-vol3-sec52-787.pdf"><span>40 CFR 52.787 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2010-07-01</p> <p>... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer <span class="hlt">vapor</span> control. (a) Gasoline means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol3/pdf/CFR-2014-title40-vol3-sec52-787.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol3/pdf/CFR-2014-title40-vol3-sec52-787.pdf"><span>40 CFR 52.787 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2014-07-01</p> <p>... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer <span class="hlt">vapor</span> control. (a) Gasoline means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRG..119..125Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRG..119..125Z"><span>The hysteretic evapotranspiration—<span class="hlt">Vapor</span> <span class="hlt">pressure</span> deficit relation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Quan; Manzoni, Stefano; Katul, Gabriel; Porporato, Amilcare; Yang, Dawen</p> <p>2014-02-01</p> <p>Diurnal hysteresis between evapotranspiration (ET) and <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit (VPD) was reported in many ecosystems, but justification for its onset and magnitude remains incomplete with biotic and abiotic factors invoked as possible explanations. To place these explanations within a holistic framework, the occurrence of hysteresis was theoretically assessed along a hierarchy of model systems where both abiotic and biotic components are sequentially added. Lysimeter evaporation (E) measurements and model calculations using the Penman equation were used to investigate the effect of the time lag between net radiation and VPD on the hysteresis in the absence of any biotic effects. Modulations from biotic effects on the ET-VPD hysteresis were then added using soil-plant-atmosphere models of different complexities applied to a grassland ecosystem. The results suggest that the hysteresis magnitude depends on the radiation-VPD lag, while the plant and soil water potentials are both key factors modulating the hysteretic ET-VPD relation as soil moisture declines. In particular, larger hysteresis magnitude is achieved at less negative leaf water potential, root water potential, and soil water potential. While plant hydraulic capacitance affects the leaf water potential-ET relation, it has negligible effects on the ET-VPD hysteresis. Therefore, the genesis and magnitude of the ET-VPD hysteresis are controlled directly by both abiotic factors such as soil water availability, biotic factors (leaf and root water potentials, which in turn depend on soil moisture), and the time lag between radiation and VPD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JTST...23..596V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JTST...23..596V"><span><span class="hlt">Vapors</span> and Droplets Mixture Deposition of Metallic Coatings by Very Low <span class="hlt">Pressure</span> Plasma Spraying</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vautherin, B.; Planche, M.-P.; Bolot, R.; Quet, A.; Bianchi, L.; Montavon, G.</p> <p>2014-04-01</p> <p>In recent years, the very low <span class="hlt">pressure</span> plasma-spraying (VLPPS) process has been intensely developed and implemented to manufacture thin, dense and finely structured ceramic coatings for various applications, such as Y2O3 for diffusion barriers, among other examples. This paper aims at presenting developments carried out on metallic coatings. Aluminum was chosen as a demonstrative material due to its "moderate" <span class="hlt">vaporization</span> enthalpy (i.e., 38.23 KJ cm-3) compared to the one of copper (i.e., 55.33 KJ cm-3), cobalt (i.e., 75.03 KJ cm-3), or even tantalum (i.e., 87.18 KJ cm-3). The objective of this work is primarily to better understand the behavior of a solid precursor injected into the plasma jet leading to the formation of <span class="hlt">vapors</span> and to better control the factors affecting the coating structure. Nearly dense aluminum coatings were successfully deposited by VLPPS at 100 Pa with an intermediate power plasma torch (i.e., Sulzer Metco F4 type gun with maximum power of 45 kW). Optical emission spectroscopy (OES) was implemented to study and analyze the <span class="hlt">vapor</span> behavior into the plasma jet. Simplified CFD modeling allowed better understanding of some of the thermo-physical mechanisms. The effect of powder-size distribution, substrate temperature and spray distance were studied. The phase composition and microstructural features of the coatings were characterized by XRD and SEM. Moreover, Vickers microhardness measurements were implemented.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol3/pdf/CFR-2010-title40-vol3-sec52-255.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title40-vol3/pdf/CFR-2010-title40-vol3-sec52-255.pdf"><span>40 CFR 52.255 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2010-07-01</p> <p>... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer <span class="hlt">vapor</span> control. (a) “Gasoline” means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol3/pdf/CFR-2014-title40-vol3-sec52-255.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol3/pdf/CFR-2014-title40-vol3-sec52-255.pdf"><span>40 CFR 52.255 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2014-07-01</p> <p>... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer <span class="hlt">vapor</span> control. (a) “Gasoline” means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol3/pdf/CFR-2013-title40-vol3-sec52-255.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol3/pdf/CFR-2013-title40-vol3-sec52-255.pdf"><span>40 CFR 52.255 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2013-07-01</p> <p>... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer <span class="hlt">vapor</span> control. (a) “Gasoline” means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol3/pdf/CFR-2011-title40-vol3-sec52-255.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title40-vol3/pdf/CFR-2011-title40-vol3-sec52-255.pdf"><span>40 CFR 52.255 - Gasoline transfer <span class="hlt">vapor</span> control.</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>... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer <span class="hlt">vapor</span> control. (a) “Gasoline” means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol3/pdf/CFR-2012-title40-vol3-sec52-255.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title40-vol3/pdf/CFR-2012-title40-vol3-sec52-255.pdf"><span>40 CFR 52.255 - Gasoline transfer <span class="hlt">vapor</span> control.</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>2012-07-01</p> <p>... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Gasoline transfer <span class="hlt">vapor</span> control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer <span class="hlt">vapor</span> control. (a) “Gasoline” means any petroleum distillate having a Reid <span class="hlt">vapor</span> <span class="hlt">pressure</span> of 4 pounds or greater...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003ApPhL..83.1207C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003ApPhL..83.1207C"><span>Growth of vertically aligned carbon nanofibers by low-<span class="hlt">pressure</span> inductively coupled plasma-enhanced chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caughman, J. B. O.; Baylor, L. R.; Guillorn, M. A.; Merkulov, V. I.; Lowndes, D. H.; Allard, L. F.</p> <p>2003-08-01</p> <p>Vertically aligned carbon nanofibers (VACNFs) have been grown using a low-<span class="hlt">pressure</span>, plasma-enhanced, chemical <span class="hlt">vapor</span> deposition process. The nanofibers are grown from a nickel catalyst that can be patterned to form arrays of individual, isolated VACNFs. The fibers are grown at <span class="hlt">pressures</span> below 100 mTorr, using an inductively coupled plasma source with a radio-frequency bias on the sample substrate to allow for independent control of the ion energies. Plasma conditions are related to growth results by comparing optical emission from the plasma to the physical structure of the nanofibers. We find that the ratio of etching species in the plasma to depositing species is critical to the final shape of the carbon structures that are formed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820031072&hterms=refraction&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Drefraction','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820031072&hterms=refraction&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Drefraction"><span>Radio jet refraction in galactic atmospheres with static <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Henriksen, R. N.; Vallee, J. P.; Bridle, A. H.</p> <p>1981-01-01</p> <p>A theory based on the refraction of radio jets in the extended atmosphere of an elliptical galaxy, is proposed for double radio sources with a Z or S morphology. The model describes a collimated jet of supersonic material that bends self-consistently under the influence of external static <span class="hlt">pressure</span> <span class="hlt">gradients</span>, and may alternatively be seen as a continuous-jet version of the buoyancy model proposed by Gull (1973). Emphasis is placed on (1) S-shaped radio sources identified with isolated galaxies, such as 3C 293, whose radio structures should be free of distortions resulting from motion relative to a cluster medium, and (2) small-scale, galaxy-dominated rather than environment-dominated S-shaped sources such as the inner jet structure of Fornax A.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150023065','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150023065"><span>Thermodynamics and Kinetics of Silicate <span class="hlt">Vaporization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jacobson, Nathan S.; Costa, Gustavo C. C.</p> <p>2015-01-01</p> <p>Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The <span class="hlt">vaporization</span> behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low <span class="hlt">vapor</span> <span class="hlt">pressures</span>. This can be circumvented by using a reducing agent to boost the <span class="hlt">vapor</span> <span class="hlt">pressure</span> without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to <span class="hlt">vaporization</span>. The measurement of these barriers, as encompassed in a <span class="hlt">vaporization</span> coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3231595','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3231595"><span>Optical Sensor for Diverse Organic <span class="hlt">Vapors</span> at ppm Concentration Ranges</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thomas, J. Christopher; Trend, John E.; Rakow, Neal A.; Wendland, Michael S.; Poirier, Richard J.; Paolucci, Dora M.</p> <p>2011-01-01</p> <p>A broadly responsive optical organic <span class="hlt">vapor</span> sensor is described that responds to low concentrations of organic <span class="hlt">vapors</span> without significant interference from water <span class="hlt">vapor</span>. Responses to several classes of organic <span class="hlt">vapors</span> are highlighted, and trends within classes are presented. The relationship between molecular properties (<span class="hlt">vapor</span> <span class="hlt">pressure</span>, boiling point, polarizability, and refractive index) and sensor response are discussed. PMID:22163798</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15518624','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15518624"><span>Development of exercise-induced arm-leg blood <span class="hlt">pressure</span> <span class="hlt">gradient</span> and abnormal arterial compliance in patients with repaired coarctation of the aorta.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Markham, Larry W; Knecht, Sandra K; Daniels, Stephen R; Mays, Wayne A; Khoury, Philip R; Knilans, Timothy K</p> <p>2004-11-01</p> <p>Often, the lack of systemic arterial hypertension and the lack of a resting arm-leg blood <span class="hlt">pressure</span> <span class="hlt">gradient</span> are used to assess the adequacy of the anatomic result after intervention for coarctation of the aorta (CoA). Some patients with no arm-leg <span class="hlt">gradient</span> at rest may develop a <span class="hlt">gradient</span> with exercise, leading caregivers to question the success of the repair. It is not clear what the prevalence is of patients who have undergone a successful intervention for CoA and have no arm-leg <span class="hlt">gradient</span> at rest but develop a significant <span class="hlt">gradient</span> with exercise and which factors may predict the development of an arm-leg <span class="hlt">gradient</span> with exercise. This study evaluates the prevalence and predictors of an exercise-induced arm-leg <span class="hlt">gradient</span> in subjects who have undergone an apparently successful intervention for CoA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090042520','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090042520"><span>Very Long Single and Few-Walled Boron Nitride Nanotubes via the <span class="hlt">Pressurized</span> <span class="hlt">Vapor</span>/Condenser Method</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Michael W.; Jordan, Kevin C.; Park, Cheol; Kim, Jae-Woo; Lillehei, Peter T.; Crooks, Roy; Harrison, Joycelyn S.</p> <p>2009-01-01</p> <p>A new method for producing long, small diameter, single and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The <span class="hlt">pressurized</span> <span class="hlt">vapor</span>/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1236848','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1236848"><span>Modeling of Propagation of Interacting Cracks Under Hydraulic <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Huang, Hai; Mattson, Earl Douglas; Podgorney, Robert Karl</p> <p></p> <p>A robust and reliable numerical model for fracture initiation and propagation, which includes the interactions among propagating fractures and the coupling between deformation, fracturing and fluid flow in fracture apertures and in the permeable rock matrix, would be an important tool for developing a better understanding of fracturing behaviors of crystalline brittle rocks driven by thermal and (or) hydraulic <span class="hlt">pressure</span> <span class="hlt">gradients</span>. In this paper, we present a physics-based hydraulic fracturing simulator based on coupling a quasi-static discrete element model (DEM) for deformation and fracturing with conjugate lattice network flow model for fluid flow in both fractures and porous matrix. Fracturingmore » is represented explicitly by removing broken bonds from the network to represent microcracks. Initiation of new microfractures and growth and coalescence of the microcracks leads to the formation of macroscopic fractures when external and/or internal loads are applied. The coupled DEM-network flow model reproduces realistic growth pattern of hydraulic fractures. In particular, simulation results of perforated horizontal wellbore clearly demonstrate that elastic interactions among multiple propagating fractures, fluid viscosity, strong coupling between fluid <span class="hlt">pressure</span> fluctuations within fractures and fracturing, and lower length scale heterogeneities, collectively lead to complicated fracturing patterns.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980227970','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980227970"><span>Charts and Tables for Estimating the Stability of the Compressible Laminar Boundary Layer with Heat Transfer and Arbitrary <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tetervin, Neal</p> <p>1959-01-01</p> <p>The minimum critical Reynolds numbers for the similar solutions of the compressible laminar boundary layer computed by Cohen and Reshotko and also for the Falkner and Skan solutions as recomputed by Smith have been calculated by Lin's rapid approximate method for two-dimensional disturbances. These results enable the stability of the compressible laminar boundary layer with heat transfer and <span class="hlt">pressure</span> <span class="hlt">gradient</span> to be easily estimated after the behavior of the boundary layer has been computed by the approximate method of Cohen and Reshotko. The previously reported unusual result (NACA Technical Note 4037) that a highly cooled stagnation point flow is more unstable than a highly cooled flat-plate flow is again encountered. Moreover, this result is found to be part of the more general result that a favorable <span class="hlt">pressure</span> <span class="hlt">gradient</span> is destabilizing for very cool walls when the Mach number is less than that for complete stability. The minimum critical Reynolds numbers for these wall temperature ratios are, however, all larger than any value of the laminar-boundary-layer Reynolds number likely to be encountered. For Mach numbers greater than those for which complete stability occurs a favorable <span class="hlt">pressure</span> <span class="hlt">gradient</span> is stabilizing, even for very cool walls.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3991613','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3991613"><span>The Influence of Body Position on Cerebrospinal Fluid <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> and Movement in Cats with Normal and Impaired Craniospinal Communication</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Radoš, Milan; Erceg, Gorislav; Petošić, Antonio; Jurjević, Ivana</p> <p>2014-01-01</p> <p>Intracranial hypertension is a severe therapeutic problem, as there is insufficient knowledge about the physiology of cerebrospinal fluid (CSF) <span class="hlt">pressure</span>. In this paper a new CSF <span class="hlt">pressure</span> regulation hypothesis is proposed. According to this hypothesis, the CSF <span class="hlt">pressure</span> depends on the laws of fluid mechanics and on the anatomical characteristics inside the cranial and spinal space, and not, as is today generally believed, on CSF secretion, circulation and absorption. The volume and <span class="hlt">pressure</span> changes in the newly developed CSF model, which by its anatomical dimensions and basic biophysical features imitates the craniospinal system in cats, are compared to those obtained on cats with and without the blockade of craniospinal communication in different body positions. During verticalization, a long-lasting occurrence of negative CSF <span class="hlt">pressure</span> inside the cranium in animals with normal cranio-spinal communication was observed. CSF <span class="hlt">pressure</span> <span class="hlt">gradients</span> change depending on the body position, but those <span class="hlt">gradients</span> do not enable unidirectional CSF circulation from the hypothetical site of secretion to the site of absorption in any of them. Thus, our results indicate the existence of new physiological/pathophysiological correlations between intracranial fluids, which opens up the possibility of new therapeutic approaches to intracranial hypertension. PMID:24748150</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24748150','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24748150"><span>The influence of body position on cerebrospinal fluid <span class="hlt">pressure</span> <span class="hlt">gradient</span> and movement in cats with normal and impaired craniospinal communication.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klarica, Marijan; Radoš, Milan; Erceg, Gorislav; Petošić, Antonio; Jurjević, Ivana; Orešković, Darko</p> <p>2014-01-01</p> <p>Intracranial hypertension is a severe therapeutic problem, as there is insufficient knowledge about the physiology of cerebrospinal fluid (CSF) <span class="hlt">pressure</span>. In this paper a new CSF <span class="hlt">pressure</span> regulation hypothesis is proposed. According to this hypothesis, the CSF <span class="hlt">pressure</span> depends on the laws of fluid mechanics and on the anatomical characteristics inside the cranial and spinal space, and not, as is today generally believed, on CSF secretion, circulation and absorption. The volume and <span class="hlt">pressure</span> changes in the newly developed CSF model, which by its anatomical dimensions and basic biophysical features imitates the craniospinal system in cats, are compared to those obtained on cats with and without the blockade of craniospinal communication in different body positions. During verticalization, a long-lasting occurrence of negative CSF <span class="hlt">pressure</span> inside the cranium in animals with normal cranio-spinal communication was observed. CSF <span class="hlt">pressure</span> <span class="hlt">gradients</span> change depending on the body position, but those <span class="hlt">gradients</span> do not enable unidirectional CSF circulation from the hypothetical site of secretion to the site of absorption in any of them. Thus, our results indicate the existence of new physiological/pathophysiological correlations between intracranial fluids, which opens up the possibility of new therapeutic approaches to intracranial hypertension.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980200978','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980200978"><span><span class="hlt">Vapor</span>-Phase Stoichiometry and Heat Treatment of CdTe Starting Material for Physical <span class="hlt">Vapor</span> Transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Su, Ching-Hua; Sha, Yi-Gao; Lehoczky, S. L.; Liu, Hao-Chieh; Fang, Rei; Brebrick, R. F.</p> <p>1998-01-01</p> <p>Six batches of CdTe, having total amounts of material from 99 to 203 g and gross mole fraction of Te, X(sub Te), 0.499954-0.500138, were synthesized from pure Cd and Te elements. The <span class="hlt">vapor</span>-phase stoichiometry of the assynthesized CdTe batches was determined from the partial <span class="hlt">pressure</span> of Te2, P(sub Te2) using an optical absorption technique. The measured <span class="hlt">vapor</span> compositions at 870 C were Te-rich for all of the batches with partial <span class="hlt">pressure</span> ratios of Cd to Te2, P(sub Cd)/P(sub Te2), ranging from 0.00742 to 1.92. After the heat treatment of baking under dynamic vacuum at 870 C for 8 min, the <span class="hlt">vapor</span>-phase compositions moved toward that of the congruent sublimation, i.e. P(sub Cd)/P(sub Te2) = 2.0, with the measured P(sub Cd)/P(sub Te2) varying from 1.84 to 3.47. The partial <span class="hlt">pressure</span> measurements on one of the heat-treated samples also showed that the sample remained close to the congruent sublimation condition over the temperature range 800-880 C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhyEd..52f3001G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhyEd..52f3001G"><span>A demonstration experiment for studying the properties of saturated <span class="hlt">vapor</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.</p> <p>2017-11-01</p> <p>The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation <span class="hlt">vapor</span>, partial <span class="hlt">pressure</span>, and the dependence of saturated <span class="hlt">vapor</span> <span class="hlt">pressure</span> on temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22972446','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22972446"><span>Preretinal partial <span class="hlt">pressure</span> of oxygen <span class="hlt">gradients</span> before and after experimental pars plana vitrectomy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Petropoulos, Ioannis K; Pournaras, Jean-Antoine C; Stangos, Alexandros N; Pournaras, Constantin J</p> <p>2013-01-01</p> <p>To evaluate preretinal partial <span class="hlt">pressure</span> of oxygen (PO2) <span class="hlt">gradients</span> before and after experimental pars plana vitrectomy. Arteriolar, venous, and intervascular preretinal PO2 <span class="hlt">gradients</span> were recorded in 7 minipigs during slow withdrawal of oxygen-sensitive microelectrodes (10-μm tip diameter) from the vitreoretinal interface to 2 mm into the vitreous cavity. Recordings were repeated after pars plana vitrectomy and balanced salt solution (BSS) intraocular perfusion. Arteriolar, venous, and intervascular preretinal PO2 at the vitreoretinal interface were 62.3 ± 13.8, 22.5 ± 3.3, and 17.0 ± 7.5 mmHg, respectively, before vitrectomy; 97.7 ± 19.9, 40.0 ± 21.9, and 56.3 ± 28.4 mmHg, respectively, immediately after vitrectomy; and 59.0 ± 27.4, 25.2 ± 3.0, and 21.5 ± 4.5 mmHg, respectively, 2½ hours after interruption of BSS perfusion. PO2 2 mm from the vitreoretinal interface was 28.4 ± 3.6 mmHg before vitrectomy; 151.8 ± 4.5 mmHg immediately after vitrectomy; and 34.8 ± 4.1 mmHg 2½ hours after interruption of BSS perfusion. PO2 <span class="hlt">gradients</span> were still present after vitrectomy, with the same patterns as before vitrectomy. Preretinal PO2 <span class="hlt">gradients</span> are not eliminated after pars plana vitrectomy. During BSS perfusion, vitreous cavity PO2 is very high. Interruption of BSS perfusion evokes progressive equilibration of vitreous cavity PO2 with concomitant progressive return of preretinal PO2 <span class="hlt">gradients</span> to their previtrectomy patterns. This indicates that preretinal diffusion of oxygen is not altered after vitrectomy. The beneficial effect of vitrectomy in ischemic retinal diseases or macular edema may be related to other mechanisms, such as increased oxygen convection currents or removal of growth factors and cytokines secreted in the vitreous.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18330185','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18330185"><span>Effect of deposition <span class="hlt">pressure</span> on the morphology and structural properties of carbon nanotubes synthesized by hot-filament chemical <span class="hlt">vapor</span> deposition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arendse, C J; Malgas, G F; Scriba, M R; Cummings, F R; Knoesen, D</p> <p>2007-10-01</p> <p>Hot-filament chemical <span class="hlt">vapor</span> deposition has developed into an attractive method for the synthesis of various carbon nanostructures, including carbon nanotubes. This is primarily due to its versatility, low cost, repeatability, up-scalability, and ease of production. The resulting nano-material synthesized by this technique is dependent on the deposition conditions which can be easily controlled. In this paper we report on the effect of the deposition <span class="hlt">pressure</span> on the structural properties and morphology of carbon nanotubes synthesized by hot-filament chemical <span class="hlt">vapor</span> deposition, using Raman spectroscopy and high-resolution scanning electron microscopy, respectively. A 10 nm-thick Ni layer, deposited on a SiO2/Si substrate, was used as catalyst for carbon nanotube growth. Multi-walled carbon nanotubes with diameters ranging from 20-100 nm were synthesized at 500 degrees C with high structural perfection at deposition <span class="hlt">pressures</span> between 150 and 200 Torr. Raman spectroscopy measurements confirm that the carbon nanotube deposit is homogeneous across the entire substrate area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25818089','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25818089"><span>Estimating evaporative <span class="hlt">vapor</span> generation from automobiles based on parking activities.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dong, Xinyi; Tschantz, Michael; Fu, Joshua S</p> <p>2015-07-01</p> <p>A new approach is proposed to quantify the evaporative <span class="hlt">vapor</span> generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative <span class="hlt">vapor</span> generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, <span class="hlt">vapor</span> generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature <span class="hlt">gradient</span>, this study uses hourly temperature observations to derive the hourly incremental <span class="hlt">vapor</span> generation rates. The parking distribution and hourly incremental <span class="hlt">vapor</span> generation rates are then adopted with Wade-Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of <span class="hlt">vapor</span> generation, and the weighted <span class="hlt">vapor</span> generation rate is 5-8% less than calculation without considering parking activity. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_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('http://adsabs.harvard.edu/abs/2017AIPC.1839b0007L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AIPC.1839b0007L"><span>Porous tungsten prepared by atmospheric-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition with WF6 and its characterization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Ying; Yu, Xiaodong; Tan, Chengwen; Wang, Fuchi; Ma, Honglei; Yue, Jintao</p> <p>2017-05-01</p> <p>Porous tungsten (W) is used in aeronautic and aerospace engineering, power electronics field and metallurgical industry. In this study, porous W with 98wt% W was prepared on a carbon foam substrate by atmospheric-<span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition (CVD) with tungsten fluoride (WF6) as the precursor. The porous W with 78.1346% porosity displayed a pure α-W phase and the uniform surface. The mode pore diameter of porous W is 208.0 µm. In a compression test, the fracture strength of porous W is 20.3 MPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28521045','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28521045"><span>Effects of ambient temperature and water <span class="hlt">vapor</span> on chamber <span class="hlt">pressure</span> and oxygen level during low atmospheric <span class="hlt">pressure</span> stunning of poultry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Holloway, Paul H; Pritchard, David G</p> <p>2017-08-01</p> <p>The characteristics of the vacuum used in a low atmospheric <span class="hlt">pressure</span> stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum <span class="hlt">pressure</span> is reduced from ambient atmospheric <span class="hlt">pressure</span> to an absolute vacuum <span class="hlt">pressure</span> of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing <span class="hlt">pressure</span>. Ambient temperature affects air density and water <span class="hlt">vapor</span> <span class="hlt">pressure</span> and thereby oxygen levels and the time at the minimum total <span class="hlt">pressure</span> of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total <span class="hlt">pressure</span> results in a gradual reduction of oxygen partial <span class="hlt">pressure</span> that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen <span class="hlt">pressure</span> leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (<span class="hlt">pressure</span> versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum <span class="hlt">pressure</span> rather than gauge <span class="hlt">pressure</span>. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the <span class="hlt">pressure</span>-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial <span class="hlt">pressure</span> of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. © The Author 2017</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title42-vol1/pdf/CFR-2010-title42-vol1-sec84-163.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title42-vol1/pdf/CFR-2010-title42-vol1-sec84-163.pdf"><span>42 CFR 84.163 - Man test for gases and <span class="hlt">vapors</span>; Type C supplied-air respirators, demand and <span class="hlt">pressure</span>-demand...</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 Man test for gases and <span class="hlt">vapors</span>; Type C supplied-air respirators, demand and <span class="hlt">pressure</span>-demand classes; test requirements. 84.163 Section 84.163 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JTST...27....3I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JTST...27....3I"><span>On the Validity of Continuum Computational Fluid Dynamics Approach Under Very Low-<span class="hlt">Pressure</span> Plasma Spray Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivchenko, Dmitrii; Zhang, Tao; Mariaux, Gilles; Vardelle, Armelle; Goutier, Simon; Itina, Tatiana E.</p> <p>2018-01-01</p> <p>Plasma spray physical <span class="hlt">vapor</span> deposition aims to substantially evaporate powders in order to produce coatings with various microstructures. This is achieved by powder <span class="hlt">vapor</span> condensation onto the substrate and/or by deposition of fine melted powder particles and nanoclusters. The deposition process typically operates at <span class="hlt">pressures</span> ranging between 10 and 200 Pa. In addition to the experimental works, numerical simulations are performed to better understand the process and optimize the experimental conditions. However, the combination of high temperatures and low <span class="hlt">pressure</span> with shock waves initiated by supersonic expansion of the hot gas in the low-<span class="hlt">pressure</span> medium makes doubtful the applicability of the continuum approach for the simulation of such a process. This work investigates (1) effects of the <span class="hlt">pressure</span> dependence of thermodynamic and transport properties on computational fluid dynamics (CFD) predictions and (2) the validity of the continuum approach for thermal plasma flow simulation under very low-<span class="hlt">pressure</span> conditions. The study compares the flow fields predicted with a continuum approach using CFD software with those obtained by a kinetic-based approach using a direct simulation Monte Carlo method (DSMC). It also shows how the presence of high <span class="hlt">gradients</span> can contribute to prediction errors for typical PS-PVD conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22463483','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22463483"><span>Thermodynamic and energy efficiency analysis of power generation from natural salinity <span class="hlt">gradients</span> by <span class="hlt">pressure</span> retarded osmosis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yip, Ngai Yin; Elimelech, Menachem</p> <p>2012-05-01</p> <p>The Gibbs free energy of mixing dissipated when fresh river water flows into the sea can be harnessed for sustainable power generation. <span class="hlt">Pressure</span> retarded osmosis (PRO) is one of the methods proposed to generate power from natural salinity <span class="hlt">gradients</span>. In this study, we carry out a thermodynamic and energy efficiency analysis of PRO work extraction. First, we present a reversible thermodynamic model for PRO and verify that the theoretical maximum extractable work in a reversible PRO process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible constant-<span class="hlt">pressure</span> PRO process is then examined. We derive an expression for the maximum extractable work in a constant-<span class="hlt">pressure</span> PRO process and show that it is less than the ideal work (i.e., Gibbs free energy of mixing) due to inefficiencies intrinsic to the process. These inherent inefficiencies are attributed to (i) frictional losses required to overcome hydraulic resistance and drive water permeation and (ii) unutilized energy due to the discontinuation of water permeation when the osmotic <span class="hlt">pressure</span> difference becomes equal to the applied hydraulic <span class="hlt">pressure</span>. The highest extractable work in constant-<span class="hlt">pressure</span> PRO with a seawater draw solution and river water feed solution is 0.75 kWh/m(3) while the free energy of mixing is 0.81 kWh/m(3)-a thermodynamic extraction efficiency of 91.1%. Our analysis further reveals that the operational objective to achieve high power density in a practical PRO process is inconsistent with the goal of maximum energy extraction. This study demonstrates thermodynamic and energetic approaches for PRO and offers insights on actual energy accessible for utilization in PRO power generation through salinity <span class="hlt">gradients</span>. © 2012 American Chemical Society</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5718776','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5718776"><span>Development of a new test cell to measure cumulative permeation of water-insoluble pesticides with low <span class="hlt">vapor</span> <span class="hlt">pressure</span> through protective clothing and glove materials</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>SHAW, Anugrah; COLEONE-CARVALHO, Ana Carla; HOLLINGSHURST, Julien; DRAPER, Michael; MACHADO NETO, Joaquim Gonçalves</p> <p>2017-01-01</p> <p>A collaborative approach, involving resources and expertise from several countries, was used to develop a test cell to measure cumulative permeation by a solid-state collection technique. The new technique was developed to measure the permeation of pesticide active ingredients and other chemicals with low <span class="hlt">vapor</span> <span class="hlt">pressure</span> that would otherwise be difficult to test via standard techniques. The development process is described and the results from the final chosen test method are reported. Inter-laboratory studies were conducted to further refine the new method and determine repeatability and reliability. The revised test method has been approved as a new ISO/EN standard to measure permeation of chemicals with low <span class="hlt">vapor</span> <span class="hlt">pressure</span> and/or solubility in water. PMID:29033403</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5402700','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5402700"><span>Elimination of Trans-coarctation <span class="hlt">Pressure</span> <span class="hlt">Gradients</span> Has No Impact on Left Ventricular Function or Aortic Shear Stress Post Intervention in Patients with Mild Coarctation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Keshavarz-Motamed, Zahra; Nezami, Farhad Rikhtegar; Partida, Ramon A.; Nakamura, Kenta; Staziaki, Pedro Vinícius; Ben-Assa, Eyal; Ghoshhajra, Brian; Bhatt, Ami B.; Edelman, Elazer R.</p> <p>2017-01-01</p> <p>OBJECTIVES To investigate the impact of transcatheter intervention on left ventricular (LV) function and aortic hemodynamics in patients with mild coarctation of the aorta (COA). BACKGROUND The optimal method and timing of transcatheter intervention for COA remains unclear, especially when the severity of COA is mild (peak-to-peak trans-coarctation <span class="hlt">pressure</span> <span class="hlt">gradient</span>, PKdP < 20 mmHg). Debate rages regarding the risk/benefit ratio of intervention vs. long-term effects of persistent minimal <span class="hlt">gradient</span> in this heterogeneous population with differing blood <span class="hlt">pressures</span>, ventricular function and peripheral perfusion. METHODS We developed a unique computational fluid dynamics and lumped parameter modeling framework based on patient-specific hemodynamic input parameters and validated it against patient-specific clinical outcomes (pre- and post-intervention). We used clinically measured hemodynamic metrics and imaging of the aorta and the LV in thirty-four patients with mild COA to make these correlations. RESULTS Despite dramatic reduction in trans-coarctation <span class="hlt">pressure</span> <span class="hlt">gradient</span> (catheter and Doppler echocardiography <span class="hlt">pressure</span> <span class="hlt">gradients</span> reduced 75% and 47.3%,), there was only modest effect on aortic flow and no significant impact on aortic shear stress (maximum time-averaged wall shear stress in descending aorta was reduced 5.1%). In no patient did transcatheter intervention improve LV function (e.g., stroke work and normalized stroke work were reduced by only 4.48% and 3.9%). CONCLUSIONS Transcatheter intervention which successfully relieves mild COA <span class="hlt">pressure</span> <span class="hlt">gradients</span> does not translate to decrease myocardial strain. The effects of intervention were determined to the greatest degree by ventricular-vascular coupling hemodynamics, and provide a novel valuable mechanism to evaluate patients with COA which may influence clinical practice. PMID:27659574</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790043970&hterms=1082&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231082','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790043970&hterms=1082&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231082"><span>Water <span class="hlt">vapor</span>-nitrogen absorption at CO2 laser frequencies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peterson, J. C.; Thomas, M. E.; Nordstrom, R. J.; Damon, E. K.; Long, R. K.</p> <p>1979-01-01</p> <p>The paper reports the results of a series of <span class="hlt">pressure</span>-broadened water <span class="hlt">vapor</span> absorption measurements at 27 CO2 laser frequencies between 935 and 1082 kaysers. Both multiple traversal cell and optoacoustic (spectrophone) techniques were utilized together with an electronically stabilized CW CO2 laser. Comparison of the results obtained by these two methods shows remarkable agreement, indicating a precision which has not been previously achieved in <span class="hlt">pressure</span>-broadened studies of water <span class="hlt">vapor</span>. The data of 10.59 microns substantiate the existence of the large (greater than 200) self-broadening coefficients determined in an earlier study by McCoy. In this work, the case of water <span class="hlt">vapor</span> in N2 at a total <span class="hlt">pressure</span> of 1 atm has been treated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030071662','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030071662"><span>Temperature <span class="hlt">Gradients</span> on the Cell Wall in the Critical Viscosity Experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Berg, Robert F.; Moldover, Michael R.</p> <p>1993-01-01</p> <p>Because of the diverging susceptibility delta rho/delta Tau near the liquid-<span class="hlt">vapor</span> critical point, temperature <span class="hlt">gradients</span> must be kept small to maintain adequate sample homogeneity. In our Science Requirements Document we paid particular attention to radial density <span class="hlt">gradients</span> caused by equilibration of the xenon sample. Axial density <span class="hlt">gradients</span> were addressed through the requirement that the cell's copper wall have a <span class="hlt">gradient</span> less than 22 microK/m. This report re-examines the cell wall's temperature distribution in more detail by estimating all known significant contributions to temperature differences on the cell's wall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFDG17002W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFDG17002W"><span>Effects of surface roughness on an adverse-<span class="hlt">pressure-gradient</span> separating turbulent boundary layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Wen; Piomelli, Ugo; Turbulence Simulation; Modelling Laboratory Team</p> <p>2017-11-01</p> <p>Separating turbulent boundary layers over smooth and rough flat plates are investigated by large-eddy simulations. A suction-blowing velocity distribution is imposed at the top boundary to produce an adverse-to-favourable <span class="hlt">pressure</span> <span class="hlt">gradient</span> and a closed separation bubble. Sandgrain roughness in the fully-rough regime is modelled by an immersed boundary method. In the rough-wall case, streamline detachment occurs earlier and the separation region is substantially larger due to the momentum deficit caused by the roughness. The adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> decreases the form drag and causes a thin reversed-flow region below the roughness crest, so that Cf = 0 does not coincide with the detachment of the flow from the surface. The wake regions behind roughness elements affect the intermittency of the near-wall flow, so that upstream of the detachment point the flow can be reversed half of the time, but its average is positive. The separated shear layer exhibits higher turbulent kinetic energy (TKE); the growth of the TKE there begins earlier relative to the separation point, and the peak TKE occurs close to the separation point. The momentum deficit caused by the roughness, again, plays a critical role in these changes. The authors acknowledge the support from Hydro-Québec and the NSERC Collaborative Research & Development program (CRDPJ 418786-11). The simulations were performed at CAC Queen't site. UP also thanks the support of Canada Research Chair Program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150003210','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150003210"><span><span class="hlt">Vapor</span>-barrier Vacuum Isolation System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)</p> <p>2014-01-01</p> <p>A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. <span class="hlt">Pressure</span> levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric <span class="hlt">vapor</span> from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing <span class="hlt">vapor</span> to a boundary with the working chamber, and supersonically expanding the <span class="hlt">vapor</span> as it enters the isolation chambers via the orifices. The <span class="hlt">vapor</span> condenses in each isolation chamber using the cooling material, and uncondensed <span class="hlt">vapor</span> is pumped out of the isolation chambers via the pump.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994JMoSt.318...79S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994JMoSt.318...79S"><span>Hydrogen bonding Part 53. Correlation of differential scanning calorimetric data with IR and dissociation <span class="hlt">vapor</span> <span class="hlt">pressure</span> studies of transitions of hexamethonium chloride and bromide dihydrates and hexamethonium bromide monohydrate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Snider, Barbara L.; Harmon, Kenneth M.</p> <p>1994-03-01</p> <p>Differential scanning calorimetry of hexamethonium chloride dihydrate shows an endothermic transition of 2.70 kcal mol -1 at 36.81°C. This correlates well with the temperatures observed by IR spectra (36°C) and equilibrium dissociation <span class="hlt">vapor</span> <span class="hlt">pressure</span> studies (37°C) for the transition between Type I planar cluster and Type II extended linear HOH⋯Cl - hydrogen bonding, and with the value of 2.77 kcal mol -1 for this transition derived by Hess' law treatment of dissociation <span class="hlt">vapor</span> <span class="hlt">pressure</span> data. Differential scanning calorimetry of hexamethonium bromide shows a rapid endothermic transition of 2.38 kcal mol -1 at 35.15°C and a very slow endothermic transition of about 12-13 kcal mol -1 centered near 50°C. This latter endotherm corresponds to the transition between Type I and Type II HOH⋯Br - hydrogen bonding observed by IR and <span class="hlt">vapor</span> <span class="hlt">pressure</span> studies at 49°C. The nature of the 35.15°C endotherm is not known. Hexamethonium bromide also shows a third endotherm at 142.91°C, which presumably results from melting of hydrate in the sealed DSC cell. Combined analysis of differential scanning calorimetry and dissociation <span class="hlt">vapor</span> <span class="hlt">pressure</span> data predicts a value of about -13 kcal mol -1 for an exothermic disproportionation at 52°C of two hexamethonium bromide monohydrate to Type II dihydrate and anhydrous bromide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25502599','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25502599"><span>Characterization of the startup transient electrokinetic flow in rectangular channels of arbitrary dimensions, zeta potential distribution, and time-varying <span class="hlt">pressure</span> <span class="hlt">gradient</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miller, Andrew; Villegas, Arturo; Diez, F Javier</p> <p>2015-03-01</p> <p>The solution to the startup transient EOF in an arbitrary rectangular microchannel is derived analytically and validated experimentally. This full 2D transient solution describes the evolution of the flow through five distinct periods until reaching a final steady state. The derived analytical velocity solution is validated experimentally for different channel sizes and aspect ratios under time-varying <span class="hlt">pressure</span> <span class="hlt">gradients</span>. The experiments used a time resolved micro particle image velocimetry technique to calculate the startup transient velocity profiles. The measurements captured the effect of time-varying <span class="hlt">pressure</span> <span class="hlt">gradient</span> fields derived in the analytical solutions. This is tested by using small reservoirs at both ends of the channel which allowed a time-varying <span class="hlt">pressure</span> <span class="hlt">gradient</span> to develop with a time scale on the order of the transient EOF. Results showed that under these common conditions, the effect of the <span class="hlt">pressure</span> build up in the reservoirs on the temporal development of the transient startup EOF in the channels cannot be neglected. The measurements also captured the analytical predictions for channel walls made of different materials (i.e., zeta potentials). This was tested in channels that had three PDMS and one quartz wall, resulting in a flow with an asymmetric velocity profile due to variations in the zeta potential between the walls. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JPhCS1001a2001A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JPhCS1001a2001A"><span>Reynolds stress structures in a self-similar adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> turbulent boundary layer at the verge of separation.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Atkinson, C.; Sekimoto, A.; Jiménez, J.; Soria, J.</p> <p>2018-04-01</p> <p>Mean Reynolds stress profiles and instantaneous Reynolds stress structures are investigated in a self-similar adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> turbulent boundary layer (APG-TBL) at the verge of separation using data from direct numerical simulations. The use of a self-similar APG-TBL provides a flow domain in which the flow gradually approaches a constant non-dimensional <span class="hlt">pressure</span> <span class="hlt">gradient</span>, resulting in a flow in which the relative contribution of each term in the governing equations is independent of streamwise position over a domain larger than two boundary layer thickness. This allows the flow structures to undergo a development that is less dependent on the upstream flow history when compared to more rapidly decelerated boundary layers. This APG-TBL maintains an almost constant shape factor of H = 2.3 to 2.35 over a momentum thickness based Reynolds number range of Re δ 2 = 8420 to 12400. In the APG-TBL the production of turbulent kinetic energy is still mostly due to the correlation of streamwise and wall-normal fluctuations, 〈uv〉, however the contribution form the other components of the Reynolds stress tensor are no longer negligible. Statistical properties associated with the scale and location of sweeps and ejections in this APG-TBL are compared with those of a zero <span class="hlt">pressure</span> <span class="hlt">gradient</span> turbulent boundary layer developing from the same inlet profile, resulting in momentum thickness based range of Re δ 2 = 3400 to 3770. In the APG-TBL the peak in both the mean Reynolds stress and the production of turbulent kinetic energy move from the near wall region out to a point consistent with the displacement thickness height. This is associated with a narrower distribution of the Reynolds stress and a 1.6 times higher relative number of wall-detached negative uv structures. These structures occupy 5 times less of the boundary layer volume and show a similar reduction in their streamwise extent with respect to the boundary layer thickness. A significantly lower percentage</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018ApPhL.112e3902J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018ApPhL.112e3902J"><span>Dynamic Leidenfrost temperature on micro-textured surfaces: Acoustic wave absorption into thin <span class="hlt">vapor</span> layer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jerng, Dong Wook; Kim, Dong Eok</p> <p>2018-01-01</p> <p>The dynamic Leidenfrost phenomenon is governed by three types of <span class="hlt">pressure</span> potentials induced via <span class="hlt">vapor</span> hydrodynamics, liquid dynamic <span class="hlt">pressure</span>, and the water hammer effect resulting from the generation of acoustic waves at the liquid-<span class="hlt">vapor</span> interface. The prediction of the Leidenfrost temperature for a dynamic droplet needs quantitative evaluation and definition for each of the <span class="hlt">pressure</span> fields. In particular, the textures on a heated surface can significantly affect the <span class="hlt">vapor</span> hydrodynamics and the water hammer <span class="hlt">pressure</span>. We present a quantitative model for evaluating the water hammer <span class="hlt">pressure</span> on micro-textured surfaces taking into account the absorption of acoustic waves into the thin <span class="hlt">vapor</span> layer. The model demonstrates that the strength of the acoustic flow into the liquid droplet, which directly contributes to the water hammer <span class="hlt">pressure</span>, depends on the magnitude of the acoustic resistance (impedance) in the droplet and the <span class="hlt">vapor</span> region. In consequence, the micro-textures of the surface and the increased spacing between them reduce the water hammer coefficient ( kh ) defined as the ratio of the acoustic flow into the droplet to total generated flow. Aided by numerical calculations that solve the laminar Navier-Stokes equation for the <span class="hlt">vapor</span> flow, we also predict the dynamic Leidenfrost temperature on a micro-textured surface with reliable accuracy consistent with the experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000072881&hterms=diamond+nanoparticles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddiamond%2Bnanoparticles','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000072881&hterms=diamond+nanoparticles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddiamond%2Bnanoparticles"><span>Growth of Carbon Nanostructure Materials Using Laser <span class="hlt">Vaporization</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhu, Shen; Su, Ching-Hua; Lehozeky, S.</p> <p>2000-01-01</p> <p>Since the potential applications of carbon nanotubes (CNT) was discovered in many fields, such as non-structure electronics, lightweight composite structure, and drug delivery, CNT has been grown by many techniques in which high yield single wall CNT has been produced by physical processes including arc <span class="hlt">vaporization</span> and laser <span class="hlt">vaporization</span>. In this presentation, the growth mechanism of the carbon nanostructure materials by laser <span class="hlt">vaporization</span> is to be discussed. Carbon nanoparticles and nanotubes have been synthesized using pulsed laser <span class="hlt">vaporization</span> on Si substrates in various temperatures and <span class="hlt">pressures</span>. Two kinds of targets were used to grow the nanostructure materials. One was a pure graphite target and the other one contained Ni and Co catalysts. The growth temperatures were 600-1000 C and the <span class="hlt">pressures</span> varied from several torr to 500 torr. Carbon nanoparticles were observed when a graphite target was used, although catalysts were deposited on substrates before growing carbon films. When the target contains catalysts, carbon nanotubes (CNT) are obtained. The CNT were characterized by scanning electron microscopy, x-ray diffraction, optical absorption and transmission, and Raman spectroscopy. The temperature-and <span class="hlt">pressure</span>-dependencies of carbon nanotubes' growth rate and size were investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/865672','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/865672"><span>Process for recovering organic <span class="hlt">vapors</span> from air</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Baker, Richard W.</p> <p>1985-01-01</p> <p>A process for recovering and concentrating organic <span class="hlt">vapor</span> from a feed stream of air having an organic <span class="hlt">vapor</span> content of no more than 20,000 ppm by volume. A thin semipermeable membrane is provided which has a feed side and a permeate side, a selectivity for organic <span class="hlt">vapor</span> over air of at least 50, as measured by the ratio of organic <span class="hlt">vapor</span> permeability to nitrogen permeability, and a permeability of organic <span class="hlt">vapor</span> of at least 3.times.10.sup.-7 cm.sup.3 (STP) cm/cm.sup.2 sec.cm Hg. The feed stream is passed across the feed side of the thin semipermeable membrane while providing a <span class="hlt">pressure</span> on the permeate side which is lower than the feed side by creating a partial vacuum on the permeate side so that organic <span class="hlt">vapor</span> passes preferentially through the membrane to form an organic <span class="hlt">vapor</span> depleted air stream on the feed side and an organic <span class="hlt">vapor</span> enriched stream on the permeate side. The organic <span class="hlt">vapor</span> which has passed through the membrane is compressed and condensed to recover the <span class="hlt">vapor</span> as a liquid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhL.107r1901H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhL.107r1901H"><span>Diamond synthesis at atmospheric <span class="hlt">pressure</span> by microwave capillary plasma chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J.</p> <p>2015-11-01</p> <p>Polycrystalline diamond has been synthesized on silicon substrates at atmospheric <span class="hlt">pressure</span>, using a microwave capillary plasma chemical <span class="hlt">vapor</span> deposition technique. The CH4/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H2 into the deposition gas chemistry. Electronically excited species of CN, C2, Ar, N2, CH, Hβ, and Hα were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T2g phonon at 1333 cm-1 peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit "coral" and "cauliflower-like" morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3288591','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3288591"><span><span class="hlt">Vapor</span> <span class="hlt">Pressure</span> of Three Brominated Flame Retardants Determined via Knudsen Effusion Method</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fu, Jinxia; Suuberg, Eric M.</p> <p>2012-01-01</p> <p>Brominated flame retardants (BFRs) have been used in a variety of consumer products in the past four decades. The <span class="hlt">vapor</span> <span class="hlt">pressures</span> for three widely used BFRs, that is, tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), and octabromodiphenyl ethers (octaBDEs) mixtures, were determined using the Knudsen effusion method and compared to those of decabromodiphenyl ether (BDE209). The values measured extrapolated to 298.15 K are 8.47 × 10−9, 7.47 × 10−10, and 2.33 × 10−9 Pa, respectively. The enthalpies of sublimation for these BFRs were estimated using the Clausius-Clapeyron equation and are 143.6 ± 0.4, 153.7 ± 3.1, and 150.8 ± 3.2 kJ/mole, respectively. In addition, the enthalpies of fusion and melting temperatures for these BFRs were also measured in the present study. PMID:22213441</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JAP....91.3847C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JAP....91.3847C"><span>Carbon nanotubes synthesized by Ni-assisted atmospheric <span class="hlt">pressure</span> thermal chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, G. S.; Cho, Y. S.; Hong, S. Y.; Park, J. B.; Son, K. H.; Kim, D. J.</p> <p>2002-03-01</p> <p>A detailed systematic study on the growth morphology of carbon nanotubes (CNTs) on Si in atmospheric <span class="hlt">pressure</span> thermal chemical <span class="hlt">vapor</span> deposition was undertaken. The role of NH3 for vertical alignment of CNTs was investigated. The direct cause for the alignment was a dense distribution of the catalytic metal particles, but that the particles are maintained catalytically active under amorphous carbon deposits was established by NH3. It allows a dense nucleation of the CNTs, and consequently, assists vertical alignment through entanglement and mechanical leaning among the tubes. The CNTs grew in a base growth mode. Since Ni is consumed both by silicide reaction and by capture into the growing tube, the growth stops when Ni is totally depleted. It occurs earlier for smaller particles, and thus a long time of growth results in a thin bottom with poor adhesion.</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://ntrs.nasa.gov/search.jsp?R=19790054016&hterms=1043&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2526%25231043','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790054016&hterms=1043&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2526%25231043"><span>Gap heating with <span class="hlt">pressure</span> <span class="hlt">gradients</span>. [for Shuttle Orbiter thermal protection system tiles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scott, C. D.; Maraia, R. J.</p> <p>1979-01-01</p> <p>The heating rate distribution and temperature response on the gap walls of insulating tiles is analyzed to determine significant phenomena and parameters in flows where there is an external surface <span class="hlt">pressure</span> <span class="hlt">gradient</span>. Convective heating due to gap flow, modeled as fully developed pipe flow, is coupled with a two-dimensional thermal model of the tiles that includes conduction and radiative heat transfer. To account for geometry and important environmental parameters, scale factors are obtained by curve-fitting measured temperatures to analytical solutions. These scale factors are then used to predict the time-dependent gap heat flux and temperature response of tile gaps on the Space Shuttle Orbiter during entry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790055911&hterms=chemical+reactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dchemical%2Breactions','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790055911&hterms=chemical+reactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dchemical%2Breactions"><span>Chemical reaction between water <span class="hlt">vapor</span> and stressed glass</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Soga, N.; Okamoto, T.; Hanada, T.; Kunugi, M.</p> <p>1979-01-01</p> <p>The crack velocity in soda-lime silicate glass was determined at room temperature at water-<span class="hlt">vapor</span> <span class="hlt">pressures</span> of 10 to 0.04 torr using the double torsion technique. A precracked glass specimen (70 x 16 x 1.6 mm) was placed in a vacuum chamber containing a four-point bending test apparatus. The plotted experimental results show that the crack propagation curve in water agrees fairly well with that of Wiederhorn (1967). Attention is given to the effect of water <span class="hlt">vapor</span> <span class="hlt">pressure</span> on crack velocity at K(I) = 550,000 N/m to the 3/2 power, with (Wiederhorn's data) or without N2 present. The plotted results reveal that the present crack velocity is about two orders of magnitude higher than that of Wiederhorn at high water-<span class="hlt">vapor</span> conditions, but the difference decreases as the water-<span class="hlt">vapor</span> concentration diminishes or the crack velocity slows down.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22314688-alkali-vapor-pressure-modulation-scale-single-cell-vacuum-system-cold-atom-experiments','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22314688-alkali-vapor-pressure-modulation-scale-single-cell-vacuum-system-cold-atom-experiments"><span>Alkali <span class="hlt">vapor</span> <span class="hlt">pressure</span> modulation on the 100 ms scale in a single-cell vacuum system for cold atom experiments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Dugrain, Vincent; Reichel, Jakob; Rosenbusch, Peter</p> <p>2014-08-15</p> <p>We describe and characterize a device for alkali <span class="hlt">vapor</span> <span class="hlt">pressure</span> modulation on the 100 ms timescale in a single-cell cold atom experiment. Its mechanism is based on optimized heat conduction between a current-modulated alkali dispenser and a heat sink at room temperature. We have studied both the short-term behavior during individual pulses and the long-term <span class="hlt">pressure</span> evolution in the cell. The device combines fast trap loading and relatively long trap lifetime, enabling high repetition rates in a very simple setup. These features make it particularly suitable for portable atomic sensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/6028680','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/6028680"><span>Lithium <span class="hlt">vapor</span>/aerosol studies. Interim summary report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Whitlow, G.A.; Bauerle, J.E.; Down, M.G.</p> <p>1979-04-01</p> <p>The temperature/cover gas <span class="hlt">pressure</span> regime, in which detectable lithium aerosol is formed in a static system has been mapped for argon and helium cover gases using a portable He--Ne laser device. At 538/sup 0/C (1000/sup 0/F), lithium aerosol particles were observed over the range 0.5 to 20 torr and 2 to 10 torr for argon and helium respectively. The experimental conditions in this study were more conducive to aerosol formation than in a fusion reactor. In the real reactor system, very high intensity mechanical and thermal disturbances will be made to the liquid lithium. These disturbances, particularly transient increases inmore » lithium <span class="hlt">vapor</span> <span class="hlt">pressure</span> appear to be capable of producing high concentrations of optically-dense aerosol. A more detailed study is, therefore, proposed using the basic information generated in these preliminary experiments, as a starting point. Areas recommended include the kinetics of aerosol formation and the occurrence of supersaturated <span class="hlt">vapor</span> during rapid <span class="hlt">vapor</span> <span class="hlt">pressure</span> transients, and also the effect of lithium agitation (falls, jets, splashing, etc.) on aerosol formation.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1251619-performance-cross-flow-humidifier-high-flux-water-vapor-transport-membrane','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1251619-performance-cross-flow-humidifier-high-flux-water-vapor-transport-membrane"><span>Performance of a Cross-Flow Humidifier with a High Flux Water <span class="hlt">Vapor</span> Transport Membrane</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ahluwalia, R. K.; Wang, X.; Johnson, W. B.</p> <p></p> <p>Water <span class="hlt">vapor</span> transport (WVT) flux across a composite membrane that consists of a very thin perfluorosulfonic acid (PFSA) ionomer layer sandwiched between two expanded polytetrafluoroethylene (PTFE) microporous layers is investigated. Static and dynamic tests are conducted to measure WVT flux for different composite structures; a transport model shows that the underlying individual resistances for water diffusion in the gas phase and microporous and ionomer layers and for interfacial kinetics of water uptake at the ionomer surface are equally important under different conditions. A finite-difference model is formulated to determine water transport in a full-scale (2-m2 active membrane area) planar cross-flowmore » humidifier module assembled using pleats of the optimized composite membrane. In agreement with the experimental data, the modeled WVT flux in the module increases at higher inlet relative humidity (RH) of the wet stream and at lower <span class="hlt">pressures</span>, but the mass transfer effectiveness is higher at higher <span class="hlt">pressures</span>. The model indicates that the WVT flux is highest under conditions that maintain the wet stream at close to 100% RH while preventing the dry stream from becoming saturated. The overall water transport is determined by the <span class="hlt">gradient</span> in RH of the wet and dry streams but is also affected by <span class="hlt">vapor</span> diffusion in the gas layer and the microporous layer.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhFl...23c2102K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhFl...23c2102K"><span>Nonlinear dynamics of confined thin liquid-<span class="hlt">vapor</span> bilayer systems with phase change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kanatani, Kentaro; Oron, Alexander</p> <p>2011-03-01</p> <p>We numerically investigate the nonlinear evolution of the interface of a thin liquid-<span class="hlt">vapor</span> bilayer system confined by rigid horizontal walls from both below and above. The lateral variation of the <span class="hlt">vapor</span> <span class="hlt">pressure</span> arising from phase change is taken into account in the present analysis. When the liquid (<span class="hlt">vapor</span>) is heated (cooled) and gravity acts toward the liquid, the deflection of the interface monotonically grows, leading to a rupture of the <span class="hlt">vapor</span> layer, whereas nonruptured stationary states are found when the liquid (<span class="hlt">vapor</span>) is cooled (heated) and gravity acts toward the <span class="hlt">vapor</span>. In the latter case, <span class="hlt">vapor</span>-flow-driven convective cells are found in the liquid phase in the stationary state. The average <span class="hlt">vapor</span> <span class="hlt">pressure</span> and interface temperature deviate from their equilibrium values once the interface departs from the flat equilibrium state. Thermocapillarity does not have a significant effect near the thermodynamic equilibrium, but becomes important if the system significantly deviates from it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25506260','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25506260"><span>Changes in intracranial <span class="hlt">pressure</span> <span class="hlt">gradients</span> between the cerebral hemispheres in patients with intracerebral hematomas in one cerebral hemisphere.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qiu, Wusi; Jiang, Qizhou; Xiao, Guoming; Wang, Weiming; Shen, Hong</p> <p>2014-01-01</p> <p>Intracranial-<span class="hlt">pressure</span> (ICP) monitoring is useful for patients with increased ICP following hemorrhagic stroke. In this study, the changes in <span class="hlt">pressure</span> <span class="hlt">gradients</span> between the two cerebral hemispheres were investigated after hemorrhagic stroke of one side, and after a craniotomy. Twenty-four patients with acute cerebral hemorrhages and intracerebral hematomas who exhibited mass effect and midline shift to the contralateral side on computed tomography were selected for this study. After admission, both sides of the cranium were drilled, and optical fiber sensors were implanted to monitor the brain parenchyma <span class="hlt">pressure</span> (BPP) in both cerebral hemispheres. All patients underwent surgical hematoma evacuations. The preoperative and postoperative BPP data from both cerebral hemispheres were collected at various time points and compared pairwise. There were statistically significant differences (P < 0.01) in the preoperative BPP values between the two hemispheres at three different time points. Differences in the BPP values between the two hemispheres at the time of surgery, and 24 and 48 h after surgery, were not statistically significant (P > 0.05). The posteroperative BPPs of both hemispheres were statistically significantly lower than preoperative recordings. BPP sensors should be applied to the injured cerebral hemisphere, because this becomes the source of increased ICP. Hematoma evacuation surgery effectively decreases ICP and eliminates <span class="hlt">pressure</span> <span class="hlt">gradients</span> between the two cerebral hemispheres, consequently enabling brain shift correction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27185055','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27185055"><span>Intrinsic advantages of packed capillaries over narrow-bore columns in very high-<span class="hlt">pressure</span> <span class="hlt">gradient</span> liquid chromatography.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gritti, Fabrice; McDonald, Thomas; Gilar, Martin</p> <p>2016-06-17</p> <p>250μm×100mm fused silica glass capillaries were packed with 1.8μm high-strength silica (HSS) fully porous particles. They were prepared without bulky stainless steel endfittings and metal frits, which both generate significant sample dispersion. The isocratic efficiencies and <span class="hlt">gradient</span> peak capacities of these prototype capillary columns were measured for small molecules (n-alkanophenones) using a home-made ultra-low dispersive micro-HPLC instrument. Their resolution power was compared to that of standard 2.1mm×100mm very high-<span class="hlt">pressure</span> liquid chromatography (vHPLC) narrow-bore columns packed with the same particles. The results show that, for the same column efficiency (25000 plates) and <span class="hlt">gradient</span> steepness (0.04min(-1)), the peak capacity of the 250μm i.d. capillary columns is systematically 15-20% higher than that of the 2.1mm i.d. narrow-bore columns. A validated model of <span class="hlt">gradient</span> chromatography enabled one to predict accurately the observed peak capacities of the capillary columns for non-linear solvation strength retention behavior and under isothermal conditions. Thermodynamics applied to the eluent quantified the temperature difference for the thermal <span class="hlt">gradients</span> in both capillary and narrow-bore columns. Experimental data revealed that the <span class="hlt">gradient</span> peak capacity is more affected by viscous heating than the column efficiency. Unlike across 2.1mm i.d. columns, the changes in eluent composition across the 250μm i.d. columns during the <span class="hlt">gradient</span> is rapidly relaxed by transverse dispersion. The combination of (1) the absence of viscous heating and (2) the high uniformity of the eluent composition across the diameter of capillary columns explains the intrinsic advantage of capillary over narrow-bore columns in <span class="hlt">gradient</span> vHPLC. Copyright © 2016 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900004432','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900004432"><span>An improved algorithm for the modeling of <span class="hlt">vapor</span> flow in heat pipes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tower, Leonard K.; Hainley, Donald C.</p> <p>1989-01-01</p> <p>A heat pipe <span class="hlt">vapor</span> flow algorithm suitable for use in codes on microcomputers is presented. The incompressible heat pipe <span class="hlt">vapor</span> flow studies of Busse are extended to incorporate compressibility effects. The Busse velocity profile factor is treated as a function of temperature and <span class="hlt">pressure</span>. The assumption of a uniform saturated <span class="hlt">vapor</span> temperature determined by the local <span class="hlt">pressure</span> at each cross section of the pipe is not made. Instead, a mean <span class="hlt">vapor</span> temperature, defined by an energy integral, is determined in the course of the solution in addition to the <span class="hlt">pressure</span>, saturation temperature at the wall, and the Busse velocity profile factor. For alkali metal working fluids, local species equilibrium is assumed. Temperature and <span class="hlt">pressure</span> profiles are presented for several cases involving sodium heat pipes. An example for a heat pipe with an adiabatic section and two evaporators in sequence illustrates the ability to handle axially varying heat input. A sonic limit plot for a short evaporator falls between curves for the Busse and Levy inviscid sonic limits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989STIN...9013748T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989STIN...9013748T"><span>An improved algorithm for the modeling of <span class="hlt">vapor</span> flow in heat pipes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tower, Leonard K.; Hainley, Donald C.</p> <p>1989-12-01</p> <p>A heat pipe <span class="hlt">vapor</span> flow algorithm suitable for use in codes on microcomputers is presented. The incompressible heat pipe <span class="hlt">vapor</span> flow studies of Busse are extended to incorporate compressibility effects. The Busse velocity profile factor is treated as a function of temperature and <span class="hlt">pressure</span>. The assumption of a uniform saturated <span class="hlt">vapor</span> temperature determined by the local <span class="hlt">pressure</span> at each cross section of the pipe is not made. Instead, a mean <span class="hlt">vapor</span> temperature, defined by an energy integral, is determined in the course of the solution in addition to the <span class="hlt">pressure</span>, saturation temperature at the wall, and the Busse velocity profile factor. For alkali metal working fluids, local species equilibrium is assumed. Temperature and <span class="hlt">pressure</span> profiles are presented for several cases involving sodium heat pipes. An example for a heat pipe with an adiabatic section and two evaporators in sequence illustrates the ability to handle axially varying heat input. A sonic limit plot for a short evaporator falls between curves for the Busse and Levy inviscid sonic limits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24296292','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24296292"><span>Very high <span class="hlt">pressure</span> liquid chromatography using fully porous particles: quantitative analysis of fast <span class="hlt">gradient</span> separations without post-run times.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stankovich, Joseph J; Gritti, Fabrice; Stevenson, Paul G; Beaver, Lois Ann; Guiochon, Georges</p> <p>2014-01-10</p> <p>Using a column packed with fully porous particles, four methods for controlling the flow rates at which <span class="hlt">gradient</span> elution runs are conducted in very high <span class="hlt">pressure</span> liquid chromatography (VHPLC) were tested to determine whether reproducible thermal conditions could be achieved, such that subsequent analyses would proceed at nearly the same initial temperature. In VHPLC high flow rates are achieved, producing fast analyses but requiring high inlet <span class="hlt">pressures</span>. The combination of high flow rates and high inlet <span class="hlt">pressures</span> generates local heat, leading to temperature changes in the column. Usually in this case a post-run time is input into the analytical method to allow the return of the column temperature to its initial state. An alternative strategy involves operating the column without a post-run equilibration period and maintaining constant temperature variations for subsequent analysis after conducting one or a few separations to bring the column to a reproducible starting temperature. A liquid chromatography instrument equipped with a <span class="hlt">pressure</span> controller was used to perform constant <span class="hlt">pressure</span> and constant flow rate VHPLC separations. Six replicate <span class="hlt">gradient</span> separations of a nine component mixture consisting of acetophenone, propiophenone, butyrophenone, valerophenone, hexanophenone, heptanophenone, octanophenone, benzophenone, and acetanilide dissolved in water/acetonitrile (65:35, v/v) were performed under various experimental conditions: constant flow rate, two sets of constant <span class="hlt">pressure</span>, and constant <span class="hlt">pressure</span> operation with a programmed flow rate. The relative standard deviations of the response factors for all the analytes are lower than 5% across the methods. Programming the flow rate to maintain a fairly constant <span class="hlt">pressure</span> instead of using instrument controlled constant <span class="hlt">pressure</span> improves the reproducibility of the retention times by a factor of 5, when plotting the chromatograms in time. Copyright © 2013 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26261969','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26261969"><span>Fabrication of Planar Heterojunction Perovskite Solar Cells by Controlled Low-<span class="hlt">Pressure</span> <span class="hlt">Vapor</span> Annealing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Yanbo; Cooper, Jason K; Buonsanti, Raffaella; Giannini, Cinzia; Liu, Yi; Toma, Francesca M; Sharp, Ian D</p> <p>2015-02-05</p> <p>A new method for achieving high efficiency planar CH3NH3I3-xClx perovskite photovoltaics, based on a low <span class="hlt">pressure</span>, reduced temperature <span class="hlt">vapor</span> annealing is demonstrated. Heterojunction devices based on this hybrid halide perovskite exhibit a top PCE of 16.8%, reduced J-V hysteresis, and highly repeatable performance without need for a mesoporous or nanocrystalline metal oxide layer. Our findings demonstrate that large hysteresis is not an inherent feature of planar heterojunctions, and that efficient charge extraction can be achieved with uniform halide perovskite materials with desired composition. X-ray diffraction, valence band spectroscopy, and transient absorption measurements of these thin films reveal that structural modifications induced by chlorine clearly dominate over chemical and electronic doping effects, without affecting the Fermi level or photocarrier lifetime in the material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034727','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034727"><span><span class="hlt">Pressure-gradient</span>-driven nearshore circulation on a beach influenced by a large inlet-tidal shoal system</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shi, F.; Hanes, D.M.; Kirby, J.T.; Erikson, L.; Barnard, P.; Eshleman, J.</p> <p>2011-01-01</p> <p>The nearshore circulation induced by a focused pattern of surface gravity waves is studied at a beach adjacent to a major inlet with a large ebb tidal shoal. Using a coupled wave and wave-averaged nearshore circulation model, it is found that the nearshore circulation is significantly affected by the heterogeneous wave patterns caused by wave refraction over the ebb tidal shoal. The model is used to predict waves and currents during field experiments conducted near the mouth of San Francisco Bay and nearby Ocean Beach. The field measurements indicate strong spatial variations in current magnitude and direction and in wave height and direction along Ocean Beach and across the ebb tidal shoal. Numerical simulations suggest that wave refraction over the ebb tidal shoal causes wave focusing toward a narrow region at Ocean Beach. Due to the resulting spatial variation in nearshore wave height, wave-induced setup exhibits a strong alongshore nonuniformity, resulting in a dramatic change in the <span class="hlt">pressure</span> field compared to a simulation with only tidal forcing. The analysis of momentum balances inside the surf zone shows that, under wave conditions with intensive wave focusing, the alongshore <span class="hlt">pressure</span> <span class="hlt">gradient</span> associated with alongshore nonuniform wave setup can be a dominant force driving circulation, inducing heterogeneous alongshore currents. <span class="hlt">Pressure-gradient</span>- forced alongshore currents can exhibit flow reversals and flow convergence or divergence, in contrast to the uniform alongshore currents typically caused by tides or homogeneous waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19970007588&hterms=zinc&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dzinc','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19970007588&hterms=zinc&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dzinc"><span>Experimental Studies on Mass Transport of Cadmium-Zinc Telluride by Physical <span class="hlt">Vapor</span> Transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Palosz, W.; Szofran, F. R.; Lehoczky, S. L.</p> <p>1995-01-01</p> <p>Experimental studies on mass transport of ternary compound, Cd(1-x)Zn(x)Te by physical <span class="hlt">vapor</span> transport (PVT) for source compositions up to X = 0.21 are presented. The effect of thermochemical (temperatures, <span class="hlt">vapor</span> composition) and other factors (preparation of the source, crystal growth rate, temperature <span class="hlt">gradient</span>) on composition and composition profiles of the grown crystals were investigated. A steep decrease in the mass flux with an increase in X(crystal) for X less than 0.1, and a difference in composition between the source and the deposited material have been observed. The composition profiles of the crystals were found to depend on the density and pretreatment of the source, and on the temperature <span class="hlt">gradient</span> in the source zone. The homogeneity of the crystals improves at low undercoolings and/or when an appropriate excess of metal constituents is present in the <span class="hlt">vapor</span> phase. The experimental results are in good agreement with our thermochemical model of this system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820043053&hterms=tellurium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtellurium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820043053&hterms=tellurium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtellurium"><span>Diffusive-convective physical <span class="hlt">vapor</span> transport of PbTe from a Te-rich solid source</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zoutendyk, J.; Akutagawa, W.</p> <p>1982-01-01</p> <p>Crystal growth of PbTe by physical <span class="hlt">vapor</span> transport (sublimation) in a closed ampoule is governed by the <span class="hlt">vapor</span> species in thermal equilibrium with the solid compound. Deviations from stoichiometry in the source material cause diffusion limitation of the transport rate, which can be modified by natural (gravity-driven) convection. Mass-transport experiments have been performed using Te-rich material wherein sublimation rates have been measured in order to study the effects of natural convection in diffusion-limited <span class="hlt">vapor</span> transport. Linear velocities for both crystal growth and evaporation (back sublimation) have been measured for transport in the direction of gravity, horizontally, and opposite to gravity. The experimental results are discussed in terms of both the one-dimensional diffusive-advective model and current, more sophisticated theory which includes natural convection. There is some evidence that convection effects from radial temperature <span class="hlt">gradients</span> and solutal density <span class="hlt">gradients</span> have been observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23767508','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23767508"><span><span class="hlt">Vapor</span>-liquid coexistence of the Stockmayer fluid in nonuniform external fields.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Samin, Sela; Tsori, Yoav; Holm, Christian</p> <p>2013-05-01</p> <p>We investigate the structure and phase behavior of the Stockmayer fluid in the presence of nonuniform electric fields using molecular simulation. We find that an initially homogeneous <span class="hlt">vapor</span> phase undergoes a local phase separation in a nonuniform field due to the combined effect of the field <span class="hlt">gradient</span> and the fluid <span class="hlt">vapor</span>-liquid equilibrium. This results in a high-density fluid condensing in the strong field region. The system polarization exhibits a strong field dependence due to the fluid condensation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A41C0049H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A41C0049H"><span>The Role of Overshooting Convection in Elevated Stratospheric Water <span class="hlt">Vapor</span> over the Summertime Continental United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herman, R. L.; Ray, E. A.; Rosenlof, K. H.; Bedka, K. M.; Schwartz, M. J.; Read, W. G.; Troy, R. F.</p> <p>2016-12-01</p> <p>The NASA ER-2 aircraft sampled the UTLS region over North America during the NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) field mission. On four flights targeting convectively-influenced air parcels, in situ measurements of enhanced water <span class="hlt">vapor</span> in the lower stratosphere over the summertime continental United States were made using the JPL Laser Hygrometer (JLH Mark2). Water <span class="hlt">vapor</span> mixing ratios greater than 10 ppmv, twice the stratospheric background levels, were measured at <span class="hlt">pressure</span> levels between 80 and 160 hPa. Through satellite observations and analysis, we make the connection between these in situ water measurements and overshooting cloud tops. The overshooting tops (OT) are identified from a SEAC4RS OT detection product based on satellite infrared window channel brightness temperature <span class="hlt">gradients</span>. Back-trajectory analysis ties enhanced water to OT one to seven days prior to the intercept by the aircraft. The trajectory paths are dominated by the North American Monsoon (NAM) anticyclonic circulation. This connection suggests that ice is convectively transported to the overworld stratosphere in OT events and subsequently sublimated; such events may irreversibly enhance stratospheric water <span class="hlt">vapor</span> in the summer over Mexico and the United States. Regional context is provided by water observations from the Aura Microwave Limb Sounder (MLS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29764373','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29764373"><span>A subclinical high tricuspid regurgitation <span class="hlt">pressure</span> <span class="hlt">gradient</span> independent of the mean pulmonary artery <span class="hlt">pressure</span> is a risk factor for the survival after living donor liver transplantation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saragai, Yosuke; Takaki, Akinobu; Umeda, Yuzo; Matsusaki, Takashi; Yasunaka, Tetsuya; Oyama, Atsushi; Kaku, Ryuji; Nakamura, Kazufumi; Yoshida, Ryuichi; Nobuoka, Daisuke; Kuise, Takashi; Takagi, Kosei; Adachi, Takuya; Wada, Nozomu; Takeuchi, Yasuto; Koike, Kazuko; Ikeda, Fusao; Onishi, Hideki; Shiraha, Hidenori; Nakamura, Shinichiro; Morimatsu, Hiroshi; Ito, Hiroshi; Fujiwara, Toshiyoshi; Yagi, Takahito; Okada, Hiroyuki</p> <p>2018-05-15</p> <p>Portopulmonary hypertension (POPH) is characterized by pulmonary vasoconstriction, while hepatopulmonary syndrome (HPS) is characterized by vasodilation. Definite POPH is a risk factor for the survival after orthotopic liver transplantation (OLT), as the congestive <span class="hlt">pressure</span> affects the grafted liver, while subclinical pulmonary hypertension (PH) has been acknowledged as a non-risk factor for deceased donor OLT. Given that PH measurement requires cardiac catheterization, the tricuspid regurgitation <span class="hlt">pressure</span> <span class="hlt">gradient</span> (TRPG) measured by echocardiography is used to screen for PH and congestive <span class="hlt">pressure</span> to the liver. We investigated the impact of a subclinical high TRPG on the survival of small grafted living donor liver transplantation (LDLT). We retrospectively analyzed 84 LDLT candidates. Patients exhibiting a TRPG ≥25 mmHg on echocardiography were categorized as potentially having liver congestion (subclinical high TRPG; n = 34). The mean pulmonary artery <span class="hlt">pressure</span> (mPAP) measured after general anesthesia with FIO 2 0.6 (mPAP-FIO 2 0.6) was also assessed. Patients exhibiting pO 2  < 80 mmHg and an alveolar-arterial oxygen <span class="hlt">gradient</span> (AaDO 2 ) ≥ 15 mmHg were categorized as potentially having HPS (subclinical HPS; n = 29). The clinical course after LDLT was investigated according to subclinical high TRPG. A subclinical high TRPG (p = 0.012) and older donor age (p = 0.008) were correlated with a poor 40-month survival. Although a higher mPAP-FIO 2 0.6 was expected to correlate with a worse survival, a high mPAP-FIO 2 0.6 with a low TRPG was associated with high frequency complicating subclinical HPS and a good survival, suggesting a reduction in the PH <span class="hlt">pressure</span> via pulmonary shunt. In cirrhosis patients, mPAP-FIO 2 0.6 may not accurately reflect the congestive <span class="hlt">pressure</span> to the liver, as the <span class="hlt">pressure</span> might escape via pulmonary shunt. A subclinical high TRPG is an important marker for predicting a worse survival after LDLT, possibly reflecting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017HMT....53.2885S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017HMT....53.2885S"><span>Numerical simulation of superheated <span class="hlt">vapor</span> bubble rising in stagnant liquid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samkhaniani, N.; Ansari, M. R.</p> <p>2017-09-01</p> <p>In present study, the rising of superheated <span class="hlt">vapor</span> bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between <span class="hlt">vapor</span>-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in <span class="hlt">vapor</span> bubble with local <span class="hlt">pressure</span> is considered with simplified Clausius-Clapeyron relation. The couple velocity-<span class="hlt">pressure</span> equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated <span class="hlt">vapor</span> bubble are investigated. The present numerical study shows <span class="hlt">vapor</span> bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810000291&hterms=heat+exchange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dheat%2Bexchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810000291&hterms=heat+exchange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dheat%2Bexchange"><span>Heat-Exchange Fluids for Sulfuric Acid <span class="hlt">Vaporizers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lawson, D. D.; Petersen, G. R.</p> <p>1982-01-01</p> <p>Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because <span class="hlt">vapor</span> <span class="hlt">pressure</span> of material decreases as DP increases, and high-DP liquids have lower loss due to <span class="hlt">vaporization</span>.</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('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3880383','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3880383"><span>A <span class="hlt">pressure-gradient</span> mechanism for vortex shedding in constricted channels</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Boghosian, M. E.; Cassel, K. W.</p> <p>2013-01-01</p> <p>Numerical simulations of the unsteady, two-dimensional, incompressible Navier–Stokes equations are performed for a Newtonian fluid in a channel having a symmetric constriction modeled by a two-parameter Gaussian distribution on both channel walls. The Reynolds number based on inlet half-channel height and mean inlet velocity ranges from 1 to 3000. Constriction ratios based on the half-channel height of 0.25, 0.5, and 0.75 are considered. The results show that both the Reynolds number and constriction geometry have a significant effect on the behavior of the post-constriction flow field. The Navier–Stokes solutions are observed to experience a number of bifurcations: steady attached flow, steady separated flow (symmetric and asymmetric), and unsteady vortex shedding downstream of the constriction depending on the Reynolds number and constriction ratio. A sequence of events is described showing how a sustained spatially growing flow instability, reminiscent of a convective instability, leads to the vortex shedding phenomenon via a proposed streamwise <span class="hlt">pressure-gradient</span> mechanism. PMID:24399860</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17352472','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17352472"><span>The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, <span class="hlt">vapor</span> <span class="hlt">pressure</span> measurements, and ab initio calculations.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas</p> <p>2007-04-04</p> <p>Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of <span class="hlt">vapor</span> <span class="hlt">pressure</span>, enthalpy of <span class="hlt">vaporization</span>, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of <span class="hlt">vaporization</span> of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the <span class="hlt">vapor</span> <span class="hlt">pressure</span> measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6548360-assessment-stenosis-severity-correlation-angiography-t1-scintigraphy-intracoronary-pressure-gradients','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/6548360-assessment-stenosis-severity-correlation-angiography-t1-scintigraphy-intracoronary-pressure-gradients"><span>Assessment of stenosis severity: Correlation of angiography, T1-201 scintigraphy, and intracoronary <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Bateman, T.; Raymond, M.; Czer, L.</p> <p>1984-01-01</p> <p>To clarify the relationship between angiographic and hemodynamic stenosis severity and the appearance during stress-redistribution myocardial T1-201 scintigraphy (Ex-T1) of a visual (V) or quantitative (Q) perfusion defect (PD) or washout (WO) abnormality, 24 pts with CAD underwent intracoronary <span class="hlt">pressure</span> <span class="hlt">gradient</span> study at bypass surgery (CABG). All had pre-CABG Ex-T1 without interval deterioration. The mean diastolic <span class="hlt">pressure</span> <span class="hlt">gradient</span> (MDG) measured at reproducible hyperemic flow rates was determined for 34 stenoses (13 LAD, 7 LCX, 14 RCA) and compared with the results of Ex-T1 in subtended myocardial regions (LAD=anterior; LCX=posterolateral; RCA=inferior). Fourteen stenoses (50-99% diameter narrowing) were unassociated with VPD despitemore » maximal exercise: MDG was 9 +- 5mmHg, with MDG/mean aortic diastolic <span class="hlt">pressure</span> (ADP) ratio of 0.12 +- 0.07. QPD and QWO analysis detected 8 of these. Thirteen stenoses (90-100% severity) led to reversible VPD: MDG was 36 +- 11 mm Hg, MDG/ADP ratio was 0.52 +- 0.17, and Q analysis was abnormal in 12/13. Seven stenoses (90-100% severity) subtended infarcted myocardium: MDG was 42 +- 21 mm Hg, MDG/ADP ratio was 0.52 +- 0.18, and V and Q analyses were abnormal in all. From this study, the authors derive the following conclusion: 1) Ex-T1 correlates better with hemodynamic severity of stenoses than does angiography; 2) V abnormalities identify stenoses of major angiographic and hemodynamic severity, while Q analysis detects some (57% in this study) stenoses of lesser severity; and 3) stenoses causing reversible Ex-T1 abnormalities present similar hemodynamic impediments to those causing myocardial infarcts.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhRvL.114o5501K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhRvL.114o5501K"><span>New Density Functional Approach for Solid-Liquid-<span class="hlt">Vapor</span> Transitions in Pure Materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kocher, Gabriel; Provatas, Nikolas</p> <p>2015-04-01</p> <p>A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-<span class="hlt">vapor</span> phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most quantitative features to date in PFC modeling of pure substances, and full consistency with thermodynamics in <span class="hlt">pressure</span>-volume-temperature space is demonstrated. A method to control either the volume or the <span class="hlt">pressure</span> of the system is also introduced. Nonequilibrium simulations show that 2- and 3-phase growth of solid, <span class="hlt">vapor</span>, and liquid can be achieved, while our formalism also allows for a full range of <span class="hlt">pressure</span>-induced transformations. This model opens up a new window for the study of <span class="hlt">pressure</span> driven interactions of condensed phases with <span class="hlt">vapor</span>, an experimentally relevant paradigm previously missing from phase field crystal theories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730012553','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730012553"><span>The behavior of a compressible turbulent boundary layer in a shock-wave-induced adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span>. Ph.D. Thesis - Washington Univ., Seattle, Aug. 1972</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rose, W. C.</p> <p>1973-01-01</p> <p>The results of an experimental investigation of the mean- and fluctuating-flow properties of a compressible turbulent boundary layer in a shock-wave-induced adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> are presented. The turbulent boundary layer developed on the wall of an axially symmetric nozzle and test section whose nominal free-stream Mach number and boundary-layer thickness Reynolds number were 4 and 100,000, respectively. The adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> was induced by an externally generated conical shock wave. Mean and time-averaged fluctuating-flow data, including the complete experimental Reynolds stress tensor and experimental turbulent mass- and heat-transfer rates are presented for the boundary layer and external flow, upstream, within and downstream of the <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The mean-flow data include distributions of total temperature throughout the region of interest. The turbulent mixing properties of the flow were determined experimentally with a hot-wire anemometer. The calibration of the wires and the interpretation of the data are discussed. From the results of the investigation, it is concluded that the shock-wave - boundary-layer interaction significantly alters the turbulent mixing characteristics of the boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22617069','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22617069"><span>[Diagnostic importance of the alveolar-arterial oxygen <span class="hlt">gradient</span>].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Weinans, Marije A E; Drost-de Klerck, Amanda M; ter Maaten, Jan C</p> <p>2012-01-01</p> <p>The alveolar-arterial (A-a) oxygen <span class="hlt">gradient</span> is the difference between the partial <span class="hlt">pressure</span> of oxygen in the alveoli and the partial <span class="hlt">pressure</span> of arterial oxygen and can be elevated in the case of pulmonary disease. We describe a 41-year-old patient with pneumonia who presented with abdominal pain, in whom calculation of the A-a <span class="hlt">gradient</span> could have led to earlier diagnosis. The A-a oxygen <span class="hlt">gradient</span> is mainly of diagnostic importance and the presented nomogram allows easy and quick interpretation. This might lead to a more frequent use of the A-a oxygen <span class="hlt">gradient</span> in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/863767','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/863767"><span>Method for controlling corrosion in thermal <span class="hlt">vapor</span> injection gases</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Sperry, John S.; Krajicek, Richard W.</p> <p>1981-01-01</p> <p>An improvement in the method for producing high <span class="hlt">pressure</span> thermal <span class="hlt">vapor</span> streams from combustion gases for injection into subterranean oil producing formations to stimulate the production of viscous minerals is described. The improvement involves controlling corrosion in such thermal <span class="hlt">vapor</span> gases by injecting water near the flame in the combustion zone and injecting ammonia into a <span class="hlt">vapor</span> producing vessel to contact the combustion gases exiting the combustion chamber.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012TRACE...2...59I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012TRACE...2...59I"><span>Characteristics of Evaporator with a Lipuid-<span class="hlt">Vapor</span> Separator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ikeguchi, Masaki; Tanaka, Naoki; Yumikura, Tsuneo</p> <p></p> <p>Flow pattern of refrigerant in a heat exchanger tube changes depending on <span class="hlt">vapor</span> quality, tube diameter, refrigerant flow rate and refrigerant properties. High flow rate causes mist flow where the quality is from 0.8 to 1.0. 1n this flow pattern, the liquid film detaches from the tube wall so that the heat flow is intervened. The heat transfer coefficient generally increases with the flow rate. But the <span class="hlt">pressure</span> drop of refrigerant flow simultaneously increases and the region of the mist flow enlarges. In order to reduce the <span class="hlt">pressure</span> drop and suppress the mist flow, we have developped a small liquid-<span class="hlt">vapor</span> separator that removes the <span class="hlt">vapor</span> from the evaporating refrigerant flow. This separator is equipped in the middle of the evaporator where the flow pattern is annular. The experiments to evaluate the effect of this separator were carried out and the following conclutions were obtained. (1) Average heat transfer coefficient increases by 30-60 %. (2) <span class="hlt">Pressure</span> drop reduces by 20-30 %. (3) Cooling Capacity increases by 2-9 %.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1335449-diamond-synthesis-atmospheric-pressure-microwave-capillary-plasma-chemical-vapor-deposition','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1335449-diamond-synthesis-atmospheric-pressure-microwave-capillary-plasma-chemical-vapor-deposition"><span>Diamond synthesis at atmospheric <span class="hlt">pressure</span> by microwave capillary plasma chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Gou, Huiyang; Hemley, Russell J.; Hemawan, Kadek W.</p> <p>2015-11-02</p> <p>Polycrystalline diamond has been successfully synthesized on silicon substrates at atmospheric <span class="hlt">pressure</span> using a microwave capillary plasma chemical <span class="hlt">vapor</span> deposition technique. The CH 4/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H2 into the deposition gas chemistry. Electronically excited species of CN, C 2, Ar, N 2, CH, H β and H α were observed in emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T 2g phonon at 1333 cm -1 peak relative to the Raman features of graphitic carbon. Furthermore, fieldmore » emission scanning electron microscopy (SEM) images reveal that, depending on the on growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NRL.....7..382G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NRL.....7..382G"><span>Luminescence of mesoporous silicon powders treated by high-<span class="hlt">pressure</span> water <span class="hlt">vapor</span> annealing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gelloz, Bernard; Loni, Armando; Canham, Leigh; Koshida, Nobuyoshi</p> <p>2012-07-01</p> <p>We have studied the photoluminescence of nanocrystalline silicon microparticle powders fabricated by fragmentation of PSi membranes. Several porosities were studied. Some powders have been subjected to further chemical etching in HF in order to reduce the size of the silicon skeleton and reach quantum sizes. High-<span class="hlt">pressure</span> water <span class="hlt">vapor</span> annealing was then used to enhance both the luminescence efficiency and stability. Two visible emission bands were observed. A red band characteristic of the emission of Si nanocrystals and a blue band related to localized centers in oxidized powders. The blue band included a long-lived component, with a lifetime exceeding 1 sec. Both emission bands depended strongly on the PSi initial porosity. The colors of the processed powders were tunable from brown to off-white, depending on the level of oxidation. The surface area and pore volume of some powders were also measured and discussed. The targeted applications are in cosmetics and medicine.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19244997','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19244997"><span>Quantification of <span class="hlt">vapor</span> intrusion pathways into a slab-on-ground building under varying environmental conditions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Patterson, Bradley M; Davis, Greg B</p> <p>2009-02-01</p> <p>Potential hydrocarbon-<span class="hlt">vapor</span> intrusion pathways into a building through a concrete slab-on-ground were investigated and quantified under a variety of environmental conditions to elucidate the potential mechanisms for indoor air contamination. <span class="hlt">Vapor</span> discharge from the uncovered open ground soil adjacent to the building and subsequent advection into the building was unlikely due to the low soil-gas concentrations at the edge of the building as a result of aerobic biodegradation of hydrocarbon <span class="hlt">vapors</span>. When the building's interior was under ambient <span class="hlt">pressure</span>, a flux of <span class="hlt">vapors</span> into the building due to molecular diffusion of <span class="hlt">vapors</span> through the building's concrete slab (cyclohexane 11 and methylcyclohexane 31 mg m(-2) concrete slab day(-1)) and short-term (up to 8 h) cyclical <span class="hlt">pressure</span>-driven advection of <span class="hlt">vapors</span> through an artificial crack (cyclohexane 4.2 x 10(3) and methylcyclohexane 1.2 x 10(4) mg m(-2) cracks day(-1)) was observed. The average subslab <span class="hlt">vapor</span> concentration under the center of the building was 25,000 microg L(-1). Based on the measured building's interiorvapor concentrations and the building's air exchange rate of 0.66 h(-1), diffusion of <span class="hlt">vapors</span> through the concrete slab was the dominantvapor intrusion pathway and cyclical <span class="hlt">pressure</span> exchanges resulted in a near zero advective flux. When the building's interior was under a reduced <span class="hlt">pressure</span> (-12 Pa), advective transport through cracks or gaps in the concrete slab (cyclohexane 340 and methylcyclohexane 1100 mg m(-2) cracks day(-1)) was the dominant <span class="hlt">vapor</span> intrusion pathway.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030002631&hterms=selenium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dselenium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030002631&hterms=selenium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dselenium"><span>Partial <span class="hlt">Pressures</span> for Several In-Se Compositions from Optical Absorbance of the <span class="hlt">Vapor</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brebrick, R. F.; Su, Ching-Hua</p> <p>2001-01-01</p> <p>The optical absorbance of the <span class="hlt">vapor</span> phase over various In-Se compositions between 33.3-60.99 at.% Se and 673-1418 K was measured and used to obtain the partial <span class="hlt">pressures</span> of Se2(g) and In2Se(g). The results are in agreement with silica Bourdon gauge measurements for compositions between 50-61 at.%, but significantly higher than those from Knudsen cell and simultaneous Knudsen-torsion cell measurements. It is found that 60.99 at.% Se lies outside the sesquiselenide homogeneity range and 59.98 at.% Se lies inside and is the congruently melting composition. The Gibbs energy of formation of the liquid from its pure liquid elements between 1000-1300 K is essentially independent of temperature and falls between -36 to -38 kJ per g atomic weight for 50 and 56% Se at 1200 and 1300 K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900014354','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900014354"><span>Aerodynamic <span class="hlt">pressure</span> and heating-rate distributions in tile gaps around chine regions with <span class="hlt">pressure</span> <span class="hlt">gradients</span> at a Mach number of 6.6</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hunt, L. Roane; Notestine, Kristopher K.</p> <p>1990-01-01</p> <p>Surface and gap <span class="hlt">pressures</span> and heating-rate distributions were obtained for simulated Thermal Protection System (TPS) tile arrays on the curved surface test apparatus of the Langley 8-Foot High Temperature Tunnel at Mach 6.6. The results indicated that the chine gap <span class="hlt">pressures</span> varied inversely with gap width because larger gap widths allowed greater venting from the gap to the lower model side <span class="hlt">pressures</span>. Lower gap <span class="hlt">pressures</span> caused greater flow ingress from the surface and increased gap heating. Generally, gap heating was greater in the longitudinal gaps than in the circumferential gaps. Gap heating decreased with increasing gap depth. Circumferential gap heating at the mid-depth was generally less than about 10 percent of the external surface value. Gap heating was most severe at local T-gap junctions and tile-to-tile forward-facing steps that caused the greatest heating from flow impingement. The use of flow stoppers at discrete locations reduced heating from flow impingement. The use of flow stoppers at discrete locations reduced heating in most gaps but increased heating in others. Limited use of flow stoppers or gap filler in longitudinal gaps could reduce gap heating in open circumferential gaps in regions of high surface <span class="hlt">pressure</span> <span class="hlt">gradients</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3635164','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3635164"><span>Investigating Individual- and Area-Level Socioeconomic <span class="hlt">Gradients</span> of Pulse <span class="hlt">Pressure</span> among Normotensive and Hypertensive Participants</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Matricciani, Lisa A.; Paquet, Catherine; Howard, Natasha J.; Adams, Robert; Coffee, Neil T.; Taylor, Anne W.; Daniel, Mark</p> <p>2013-01-01</p> <p>Socioeconomic status is a strong predictor of cardiovascular disease. Pulse <span class="hlt">pressure</span>, the difference between systolic and diastolic blood <span class="hlt">pressure</span>, has been identified as an important predictor of cardiovascular risk even after accounting for absolute measures of blood <span class="hlt">pressure</span>. However, little is known about the social determinants of pulse <span class="hlt">pressure</span>. The aim of this study was to examine individual- and area-level socioeconomic <span class="hlt">gradients</span> of pulse <span class="hlt">pressure</span> in a sample of 2,789 Australian adults. Using data from the North West Adelaide Health Study we estimated the association between pulse <span class="hlt">pressure</span> and three indices of socioeconomic status (education, income and employment status) at the area and individual level for hypertensive and normotensive participants, using Generalized Estimating Equations. In normotensive individuals, area-level education (estimate: −0.106; 95% CI: −0.172, −0.041) and individual-level income (estimate: −1.204; 95% CI: −2.357, −0.050) and employment status (estimate: −1.971; 95% CI: −2.894, −1.048) were significant predictors of pulse <span class="hlt">pressure</span>, even after accounting for the use of medication and lifestyle behaviors. In hypertensive individuals, only individual-level measures of socioeconomic status were significant predictors of pulse <span class="hlt">pressure</span> (education estimate: −2.618; 95% CI: −4.878, −0.357; income estimate: −1.683, 95% CI: −3.743, 0.377; employment estimate: −2.023; 95% CI: −3.721, −0.326). Further research is needed to better understand how individual- and area-level socioeconomic status influences pulse <span class="hlt">pressure</span> in normotensive and hypertensive individuals. PMID:23380912</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1214554-doping-electronic-properties-gaas-grown-close-spaced-vapor-transport-from-powder-sources-scalable-iiiv-photovoltaics','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1214554-doping-electronic-properties-gaas-grown-close-spaced-vapor-transport-from-powder-sources-scalable-iiiv-photovoltaics"><span>Doping and electronic properties of GaAs grown by close-spaced <span class="hlt">vapor</span> transport from powder sources for scalable III–V photovoltaics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Ritenour, Andrew J.; Boucher, Jason W.; DeLancey, Robert; ...</p> <p>2014-09-01</p> <p>The high balance-of-system costs of photovoltaic (PV) installations indicate that reductions in cell $/W costs alone are likely insufficient for PV electricity to reach grid parity unless energy conversion efficiency is also increased. Technologies which yield both high-efficiency cells (>25%) and maintain low costs are needed. GaAs and related III-V semiconductors are used in the highest-efficiency single- and multi-junction photovoltaics, but the technology is too expensive for non-concentrated terrestrial applications. This is due in part to the difficulty of scaling the metal-organic chemical <span class="hlt">vapor</span> deposition (MOCVD) process, which relies on expensive reactors and employs toxic and pyrophoric gas-phase precursors suchmore » as arsine and trimethyl gallium, respectively. In this study, we describe GaAs films made by an alternative close-spaced <span class="hlt">vapor</span> transport (CSVT) technique which is carried out at atmospheric <span class="hlt">pressure</span> and requires only bulk GaAs, water <span class="hlt">vapor</span>, and a temperature <span class="hlt">gradient</span> in order to deposit crystalline films with similar electronic properties to that of GaAs deposited by MOCVD. CSVT is similar to the <span class="hlt">vapor</span> transport process used to deposit CdTe thin films and is thus a potentially scalable low-cost route to GaAs thin films.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33D2792K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33D2792K"><span>Impact <span class="hlt">Vaporization</span> of Planetesimal Cores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kraus, R. G.; Root, S.; Lemke, R. W.; Stewart, S. T.; Jacobsen, S. B.; Mattsson, T. R.</p> <p>2013-12-01</p> <p>The degree of mixing and chemical equilibration between the iron cores of planetesimals and the mantle of the growing Earth has important consequences for understanding the end stages of Earth's formation and planet formation in general. At the Sandia Z machine, we developed a new shock-and-release technique to determine the density on the liquid-<span class="hlt">vapor</span> dome of iron, the entropy on the iron shock Hugoniot, and the criteria for shock-induced <span class="hlt">vaporization</span> of iron. We find that the critical shock <span class="hlt">pressure</span> to <span class="hlt">vaporize</span> iron is 507(+65,-85) GPa and show that decompression from a 15 km/s impact will initiate <span class="hlt">vaporization</span> of iron cores, which is a velocity that is readily achieved at the end stages of planet formation. <span class="hlt">Vaporization</span> of the iron cores increases dispersal of planetesimal cores, enables more complete chemical equilibration of the planetesimal cores with Earth's mantle, and reduces the highly siderophile element abundance on the Moon relative to Earth due to the expanding iron <span class="hlt">vapor</span> exceeding the Moon's escape velocity. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Securities Administration under Contract No. DE-AC04-94AL85000.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4437633','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4437633"><span>Ex-Vivo Lymphatic Perfusion System for Independently Controlling <span class="hlt">Pressure</span> <span class="hlt">Gradient</span> and Transmural <span class="hlt">Pressure</span> in Isolated Vessels</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kornuta, Jeffrey A.; Dixon, J. Brandon</p> <p>2015-01-01</p> <p>In addition to external forces, collecting lymphatic vessels intrinsically contract to transport lymph from the extremities to the venous circulation. As a result, the lymphatic endothelium is routinely exposed to a wide range of dynamic mechanical forces, primarily fluid shear stress and circumferential stress, which have both been shown to affect lymphatic pumping activity. Although various ex-vivo perfusion systems exist to study this innate pumping activity in response to mechanical stimuli, none are capable of independently controlling the two primary mechanical forces affecting lymphatic contractility: transaxial <span class="hlt">pressure</span> <span class="hlt">gradient</span>, ΔP, which governs fluid shear stress; and average transmural <span class="hlt">pressure</span>, Pavg, which governs circumferential stress. Hence, the authors describe a novel ex-vivo lymphatic perfusion system (ELPS) capable of independently controlling these two outputs using a linear, explicit model predictive control (MPC) algorithm. The ELPS is capable of reproducing arbitrary waveforms within the frequency range observed in the lymphatics in vivo, including a time-varying ΔP with a constant Pavg, time-varying ΔP and Pavg, and a constant ΔP with a time-varying Pavg. In addition, due to its implementation of syringes to actuate the working fluid, a post-hoc method of estimating both the flow rate through the vessel and fluid wall shear stress over multiple, long (5 sec) time windows is also described. PMID:24809724</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25138664','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25138664"><span>The role of jet eccentricity in generating disproportionately elevated transaortic <span class="hlt">pressure</span> <span class="hlt">gradients</span> in patients with aortic stenosis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abbas, Amr E; Franey, Laura M; Lester, Steven; Raff, Gilbert; Gallagher, Michael J; Hanzel, George; Safian, Robert D; Pibarot, Philippe</p> <p>2015-02-01</p> <p>In patients with aortic stenosis (AS) and eccentric transaortic flow, greater <span class="hlt">pressure</span> loss occurs as the jet collides with the aortic wall together with delayed and diminished <span class="hlt">pressure</span> recovery. This leads to the elevated transaortic valve <span class="hlt">pressure</span> <span class="hlt">gradients</span> noted on both Doppler and cardiac catheterization. Such situations may present a diagnostic dilemma where traditional measures of stenosis severity indicate severe AS, while imaging modalities of the aortic valve geometric aortic valve area (GOA) suggest less than severe stenosis. In this study, we present a series of cases exemplifying this clinical dilemma and demonstrate how color M-mode, 2D and 3D transthoracic (TTE) and transesophageal (TEE) echocardiography, cardiac computed tomography angiography (CTA), and magnetic resonance imaging (MRI), may be used to resolve such discrepancies. © 2014, Wiley Periodicals, Inc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27743249','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27743249"><span>The association between the pulse <span class="hlt">pressure</span> <span class="hlt">gradient</span> at the cranio-cervical junction derived from phase-contrast magnetic resonance imaging and invasively measured pulsatile intracranial <span class="hlt">pressure</span> in symptomatic patients with Chiari malformation type 1.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Frič, Radek; Lindstrøm, Erika Kristina; Ringstad, Geir Andre; Mardal, Kent-André; Eide, Per Kristian</p> <p>2016-12-01</p> <p>In symptomatic Chiari malformation type 1 (CMI), impaired intracranial compliance (ICC) is associated with an increased cranio-spinal pulsatile <span class="hlt">pressure</span> <span class="hlt">gradient</span>. Phase-contrast magnetic resonance imaging (MRI) represents a non-invasive modality for the assessment of the pulse <span class="hlt">pressure</span> <span class="hlt">gradient</span> at the cranio-cervical junction (CCJ). We wished to explore how the MRI-derived pulse <span class="hlt">pressure</span> <span class="hlt">gradient</span> (MRI-dP) compares with invasively measured pulsatile intracranial <span class="hlt">pressure</span> (ICP) in CMI, and with healthy controls. From phase-contrast MRI of CMI patients and healthy controls, we computed cerebrospinal fluid (CSF) flow velocities and MRI-dP at the CCJ. We assessed bidirectional flow and compared the flow between the anterior and the posterior subarachnoid space at the CCJ. We computed total intracranial volume (ICV), ventricular CSF volume (VV), and posterior cranial fossa volume (PCFV). We analyzed the static and pulsatile ICP scores from overnight monitoring in CMI patients. Five CMI patients and four healthy subjects were included. The CMI group had a significantly larger extent of tonsillar ectopia, smaller PCFV, and a smaller area of CSF in the FM. The pulsatile ICP (mean ICP wave amplitude, MWA) was abnormally increased in 4/5 CMI patients and correlated positively with MRI-dP. However, the MRI-dP as well as the CSF flow velocities did not differ significantly between CMI and healthy subjects. Moreover, bidirectional flow was observed in both CMI as well as healthy subjects, with no significant difference. In symptomatic CMI patients, we found a significant association between the pulse <span class="hlt">pressure</span> <span class="hlt">gradient</span> at the CCJ derived from phase-contrast MRI and the pulsatile ICP (MWA) measured invasively. However, the MRI-dP was close to identical in CMI patients and healthy subjects. Moreover, the CSF flow velocities at the CCJ and the occurrence of bidirectional flow were not different in CMI patients and healthy individuals. Further studies are required to determine the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910000460&hterms=Miyake&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMiyake','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910000460&hterms=Miyake&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMiyake"><span><span class="hlt">Vaporization</span> Would Cool Primary Battery</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bhandari, Pradeep; Miyake, Robert N.</p> <p>1991-01-01</p> <p>Temperature of discharging high-power-density primary battery maintained below specified level by evaporation of suitable liquid from jacket surrounding battery, according to proposal. <span class="hlt">Pressure</span>-relief valve regulates <span class="hlt">pressure</span> and boiling temperature of liquid. Less material needed in cooling by <span class="hlt">vaporization</span> than in cooling by melting. Technique used to cool batteries in situations in which engineering constraints on volume, mass, and location prevent attachment of cooling fins, heat pipes, or like.</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('http://adsabs.harvard.edu/abs/2017SPIE10328E..1AH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SPIE10328E..1AH"><span>Condensation of <span class="hlt">vapor</span> bubble in subcooled pool</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.</p> <p>2017-02-01</p> <p>We focus on condensation process of <span class="hlt">vapor</span> bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of <span class="hlt">vapor</span> into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric <span class="hlt">pressure</span> condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the <span class="hlt">vapor</span> bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare <span class="hlt">vapor</span> in the <span class="hlt">vapor</span> generator instead of the evaporation on the heated surface, and inject the <span class="hlt">vapor</span> to expose the <span class="hlt">vapor</span> bubble to the subcooled liquid. Special attention is paid to the dynamics of the <span class="hlt">vapor</span> bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25985421','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25985421"><span>Impact of air and water <span class="hlt">vapor</span> environments on the hydrophobicity of surfaces.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Weisensee, Patricia B; Neelakantan, Nitin K; Suslick, Kenneth S; Jacobi, Anthony M; King, William P</p> <p>2015-09-01</p> <p>Droplet wettability and mobility play an important role in dropwise condensation heat transfer. Heat exchangers and heat pipes operate at liquid-<span class="hlt">vapor</span> saturation. We hypothesize that the wetting behavior of liquid water on microstructures surrounded by pure water <span class="hlt">vapor</span> differs from that for water droplets in air. The static and dynamic contact angles and contact angle hysteresis of water droplets were measured in air and pure water <span class="hlt">vapor</span> environments inside a <span class="hlt">pressure</span> vessel. <span class="hlt">Pressures</span> ranged from 60 to 1000 mbar, with corresponding saturation temperatures between 36 and 100°C. The wetting behavior was studied on four hydrophobic surfaces: flat Teflon-coated, micropillars, micro-scale meshes, and nanoparticle-coated with hierarchical micro- and nanoscale roughness. Static advancing contact angles are 9° lower in the water <span class="hlt">vapor</span> environment than in air on a flat surface. One explanation for this reduction in contact angles is water <span class="hlt">vapor</span> adsorption to the Teflon. On microstructured surfaces, the <span class="hlt">vapor</span> environment has little effect on the static contact angles. In all cases, variations in <span class="hlt">pressure</span> and temperature do not influence the wettability and mobility of the water droplets. In most cases, advancing contact angles increase and contact angle hysteresis decreases when the droplets are sliding or rolling down an inclined surface. Copyright © 2015 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840015581','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840015581"><span>Investigation of the effects of <span class="hlt">pressure</span> <span class="hlt">gradient</span>, temperature and wall temperature ratio on the stagnation point heat transfer for circular cylinders and gas turbine vanes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nagamatsu, H. T.; Duffy, R. E.</p> <p>1984-01-01</p> <p>Low and high <span class="hlt">pressure</span> shock tubes were designed and constructed for the purpose of obtaining heat transfer data over a temperature range of 390 to 2500 K, <span class="hlt">pressures</span> of 0.3 to 42 atm, and Mach numbers of 0.15 to 1.5 with and without <span class="hlt">pressure</span> <span class="hlt">gradient</span>. A square test section with adjustable top and bottom walls was constructed to produce the favorable and adverse <span class="hlt">pressure</span> <span class="hlt">gradient</span> over the flat plate with heat gages. A water cooled gas turbine nozzle cascade which is attached to the high <span class="hlt">pressure</span> shock tube was obtained to measuse the heat flux over <span class="hlt">pressure</span> and suction surfaces. Thin-film platinum heat gages with a response time of a few microseconds were developed and used to measure the heat flux for laminar, transition, and turbulent boundary layers. The laminar boundary heat flux on the shock tube wall agreed with Mirel's flat plate theory. Stagnation point heat transfer for circular cylinders at low temperature compared with the theoretical prediction, but for a gas temperature of 922 K the heat fluxes were higher than the predicted values. Preliminary flat plate heat transfer data were measured for laminar, transition, and turbulent boundary layers with and without <span class="hlt">pressure</span> <span class="hlt">gradients</span> for free-stream temperatures of 350 to 2575 K and flow Mach numbers of 0.11 to 1.9. The experimental heat flux data were correlated with the laminar and turbulent theories and the agreement was good at low temperatures which was not the case for higher temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150021282','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150021282"><span>Effect of Interfacial Turbulence and Accommodation Coefficient on CFD Predictions of <span class="hlt">Pressurization</span> and <span class="hlt">Pressure</span> Control in Cryogenic Storage Tank</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kassemi, Mohammad; Kartuzova, Olga; Hylton, Sonya</p> <p>2015-01-01</p> <p>Laminar models agree closely with the <span class="hlt">pressure</span> evolution and <span class="hlt">vapor</span> phase temperature stratification but under-predict liquid temperatures. Turbulent SST k-w and k-e models under-predict the <span class="hlt">pressurization</span> rate and extent of stratification in the <span class="hlt">vapor</span> but represent liquid temperature distributions fairly well. These conclusions seem to equally apply to large cryogenic tank simulations as well as small scale simulant fluid <span class="hlt">pressurization</span> cases. Appropriate turbulent models that represent both interfacial and bulk <span class="hlt">vapor</span> phase turbulence with greater fidelity are needed. Application of LES models to the tank <span class="hlt">pressurization</span> problem can serve as a starting point.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16657786','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16657786"><span>Water potential <span class="hlt">gradient</span> in a tall sequoiadendron.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tobiessen, P</p> <p>1971-09-01</p> <p>With an elevator installed in a 90-meter tall Sequoiadendron to collect the samples, xylem <span class="hlt">pressure</span> potential measurements were made approximately every 15 meters along 60 meters of the tree's height. The measured <span class="hlt">gradient</span> was about -0.8 bar per 10 meters of height, i.e., less than the hydrostatic <span class="hlt">gradient</span>. Correction of the xylem <span class="hlt">pressure</span> potential data by calibration against a thermocouple psychrometer confirmed this result. Similar <span class="hlt">gradients</span> are described in the literature in tall conifers at times of low transpiration, although a different sampling technique was used. If the data in the present study and those supporting it are typical, they imply a re-evaluation of either the use of the <span class="hlt">pressure</span> chamber to estimate water potential or the present theories describing water transport in tall trees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=396854','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=396854"><span>Water Potential <span class="hlt">Gradient</span> in a Tall Sequoiadendron</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tobiessen, Peter; Rundel, Philip W.; Stecker, R. E.</p> <p>1971-01-01</p> <p>With an elevator installed in a 90-meter tall Sequoiadendron to collect the samples, xylem <span class="hlt">pressure</span> potential measurements were made approximately every 15 meters along 60 meters of the tree's height. The measured <span class="hlt">gradient</span> was about −0.8 bar per 10 meters of height, i.e., less than the hydrostatic <span class="hlt">gradient</span>. Correction of the xylem <span class="hlt">pressure</span> potential data by calibration against a thermocouple psychrometer confirmed this result. Similar <span class="hlt">gradients</span> are described in the literature in tall conifers at times of low transpiration, although a different sampling technique was used. If the data in the present study and those supporting it are typical, they imply a re-evaluation of either the use of the <span class="hlt">pressure</span> chamber to estimate water potential or the present theories describing water transport in tall trees. PMID:16657786</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740025322','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740025322"><span>Boundary-layer transition on a plate subjected to simultaneous spanwise and chordwise <span class="hlt">pressure</span> <span class="hlt">gradients</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Boldman, D. R.; Brinich, P. F.</p> <p>1974-01-01</p> <p>The boundary-layer transition on a short plate was studied by means of the china-clay visual technique. The plate model was mounted in a wind tunnel so that it was subjected to small simultaneous spanwise and chordwise <span class="hlt">pressure</span> <span class="hlt">gradients</span>. Results of the experimental study, which was performed at three subsonic velocities, indicated that the transition pattern was appreciably curved in the spanwise direction but quite smooth and well behaved. Reasonable comparisons between predictions of transition and experiment were obtained from two finite-difference two-dimensional boundary-layer calculation methods which incorporated transition models based on the concept of a transition intermittency factor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018APLM....6d6105J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018APLM....6d6105J"><span>Conformal coating of amorphous silicon and germanium by high <span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition for photovoltaic fabrics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ji, Xiaoyu; Cheng, Hiu Yan; Grede, Alex J.; Molina, Alex; Talreja, Disha; Mohney, Suzanne E.; Giebink, Noel C.; Badding, John V.; Gopalan, Venkatraman</p> <p>2018-04-01</p> <p>Conformally coating textured, high surface area substrates with high quality semiconductors is challenging. Here, we show that a high <span class="hlt">pressure</span> chemical <span class="hlt">vapor</span> deposition process can be employed to conformally coat the individual fibers of several types of flexible fabrics (cotton, carbon, steel) with electronically or optoelectronically active materials. The high <span class="hlt">pressure</span> (˜30 MPa) significantly increases the deposition rate at low temperatures. As a result, it becomes possible to deposit technologically important hydrogenated amorphous silicon (a-Si:H) from silane by a simple and very practical pyrolysis process without the use of plasma, photochemical, hot-wire, or other forms of activation. By confining gas phase reactions in microscale reactors, we show that the formation of undesired particles is inhibited within the microscale spaces between the individual wires in the fabric structures. Such a conformal coating approach enables the direct fabrication of hydrogenated amorphous silicon-based Schottky junction devices on a stainless steel fabric functioning as a solar fabric.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......146A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......146A"><span>Design and development of second order MEMS sound <span class="hlt">pressure</span> <span class="hlt">gradient</span> sensor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Albahri, Shehab</p> <p></p> <p>The design and development of a second order MEMS sound <span class="hlt">pressure</span> <span class="hlt">gradient</span> sensor is presented in this dissertation. Inspired by the directional hearing ability of the parasitoid fly, Ormia ochracea, a novel first order directional microphone that mimics the mechanical structure of the fly's ears and detects the sound <span class="hlt">pressure</span> <span class="hlt">gradient</span> has been developed. While the first order directional microphones can be very beneficial in a large number of applications, there is great potential for remarkable improvements in performance through the use of second order systems. The second order directional microphone is able to provide a theoretical improvement in Sound to Noise ratio (SNR) of 9.5dB, compared to the first-order system that has its maximum SNR of 6dB. Although second order microphone is more sensitive to sound angle of incidence, the nature of the design and fabrication process imposes different factors that could lead to deterioration in its performance. The first Ormia ochracea second order directional microphone was designed in 2004 and fabricated in 2006 at Binghamton University. The results of the tested parts indicate that the Ormia ochracea second order directional microphone performs mostly as an Omni directional microphone. In this work, the previous design is reexamined and analyzed to explain the unexpected results. A more sophisticated tool implementing a finite element package ANSYS is used to examine the previous design response. This new tool is used to study different factors that used to be ignored in the previous design, mainly; response mismatch and fabrication uncertainty. A continuous model using Hamilton's principle is introduced to verify the results using the new method. Both models agree well, and propose a new way for optimizing the second order directional microphone using geometrical manipulation. In this work we also introduce a new fabrication process flow to increase the fabrication yield. The newly suggested method uses the shell</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1436064','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1436064"><span>Auxiliary Electrodes for Chromium <span class="hlt">Vapor</span> Sensors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Fergus, Jeffrey; Shahzad, Moaiz; Britt, Tommy</p> <p></p> <p>Measurement of chromia-containing <span class="hlt">vapors</span> in solid oxide fuel cell systems is useful for monitoring and addressing cell degradation caused by oxidation of the chomia scale formed on alloys for interconnects and balance-of-plant components. One approach to measuring chromium is to use a solid electrolyte with an auxiliary electrode that relates the partial <span class="hlt">pressure</span> of the chromium containing species to the mobile species in the electrolyte. One example is YCrO3 which can equilibrate with the chromium containing <span class="hlt">vapor</span> and yttrium in yttria stabilized zirconia to establish an oxygen activity. Another is Na2CrO4 which can equilibrate with the chromium-containing <span class="hlt">vapor</span> to establishmore » a sodium activity.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22436563-vapor-pressures-dialkylimidazolium-bis-trifluoromethylsulfonyl-imide-ionic-liquids-long-alkyl-chains','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22436563-vapor-pressures-dialkylimidazolium-bis-trifluoromethylsulfonyl-imide-ionic-liquids-long-alkyl-chains"><span><span class="hlt">Vapor</span> <span class="hlt">pressures</span> of 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids with long alkyl chains</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Rocha, Marisa A. A., E-mail: lbsantos@fc.up.pt, E-mail: marisa.alexandra.rocha@gmail.com; Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven; Coutinho, João A. P.</p> <p>2014-10-07</p> <p>This work presents the <span class="hlt">vapor</span> <span class="hlt">pressure</span> at several temperatures for the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide series, [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (N = 14, 16, 18, and 20), measured by a Knudsen effusion method combined with a quartz crystal microbalance. The thermodynamic properties of <span class="hlt">vaporization</span> of the ionic liquids under study are analysed together with the results obtained previously for the shorter alkyl chain length [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (N = 2, 4, 6, 8, 10, and 12), in order to evaluate the effect of the alkyl side chains of the cation and to get additional insights concerning the nanostructuration of ionic liquids.more » The symmetry effect is explored, based on the comparison with the asymmetric imidazolium based ionic liquids, [C{sub N-1}C{sub 1}im][NTf{sub 2}]. A trend shift on the thermodynamic properties of <span class="hlt">vaporization</span> along the alkyl side chains of the extended symmetric ionic liquids, around [C{sub 6}C{sub 6}im][NTf{sub 2}], was detected. An intensification of the odd-even effect was observed starting from [C{sub 6}C{sub 6}im][NTf{sub 2}], with higher enthalpies and entropies of <span class="hlt">vaporization</span> for the odd numbered ionic liquids, [C{sub 7}C{sub 7}im][NTf{sub 2}] and [C{sub 9}C{sub 9}im][NTf{sub 2}]. Similar, but less pronounced, odd-even effect was found for the symmetric ionic liquids with lower alkyl side chains length, [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (with N = 4, 6, 8, 10, and 12). This effect is related with the predominant orientation of the terminal methyl group of the alkyl chain to the imidazolium ring and their influence in the cation-anion interaction. The same Critical Alkyl length at the hexyl, (C{sub 6}C{sub 1}and C{sub 6}C{sub 6}) was found for both asymmetric and symmetric series indicating that the nanostructuration of the ionic liquids is related with alkyl chain length.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22778438','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22778438"><span>Redox systematics of a magma ocean with variable <span class="hlt">pressure</span>-temperature <span class="hlt">gradients</span> and composition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Righter, K; Ghiorso, M S</p> <p>2012-07-24</p> <p>Oxygen fugacity in metal-bearing systems controls some fundamental aspects of the geochemistry of the early Earth, such as the FeO and siderophile trace element content of the mantle, volatile species that influence atmospheric composition, and conditions for organic compounds synthesis. Redox and metal-silicate equilibria in the early Earth are sensitive to oxygen fugacity (fO(2)), yet are poorly constrained in modeling and experimentation. High <span class="hlt">pressure</span> and temperature experimentation and modeling in metal-silicate systems usually employs an approximation approach for estimating fO(2) that is based on the ratio of Fe and FeO [called "ΔIW (ratio)" hereafter]. We present a new approach that utilizes free energy and activity modeling of the equilibrium: Fe + SiO(2) + O(2) = Fe(2)SiO(4) to calculate absolute fO(2) and relative to the iron-wüstite (IW) buffer at <span class="hlt">pressure</span> and temperature [ΔIW (P,T)]. This equilibrium is considered across a wide range of <span class="hlt">pressures</span> and temperatures, including up to the liquidus temperature of peridotite (4,000 K at 50 GPa). Application of ΔIW (ratio) to metal-silicate experiments can be three or four orders of magnitude different from ΔIW (P,T) values calculated using free energy and activity modeling. We will also use this approach to consider the variation in oxygen fugacity in a magma ocean scenario for various thermal structures for the early Earth: hot liquidus <span class="hlt">gradient</span>, 100 °C below the liquidus, hot and cool adiabatic <span class="hlt">gradients</span>, and a cool subsolidus adiabat. The results are used to assess the effect of increasing P and T, changing silicate composition during accretion, and related to current models for accretion and core formation in the Earth. The fO(2) in a deep magma ocean scenario may become lower relative to the IW buffer at hotter and deeper conditions, which could include metal entrainment scenarios. Therefore, fO(2) may evolve from high to low fO(2) during Earth (and other differentiated bodies) accretion. Any</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3409746','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3409746"><span>Redox systematics of a magma ocean with variable <span class="hlt">pressure</span>-temperature <span class="hlt">gradients</span> and composition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Righter, K.; Ghiorso, M. S.</p> <p>2012-01-01</p> <p>Oxygen fugacity in metal-bearing systems controls some fundamental aspects of the geochemistry of the early Earth, such as the FeO and siderophile trace element content of the mantle, volatile species that influence atmospheric composition, and conditions for organic compounds synthesis. Redox and metal-silicate equilibria in the early Earth are sensitive to oxygen fugacity (fO2), yet are poorly constrained in modeling and experimentation. High <span class="hlt">pressure</span> and temperature experimentation and modeling in metal-silicate systems usually employs an approximation approach for estimating fO2 that is based on the ratio of Fe and FeO [called “ΔIW (ratio)” hereafter]. We present a new approach that utilizes free energy and activity modeling of the equilibrium: Fe + SiO2 + O2 = Fe2SiO4 to calculate absolute fO2 and relative to the iron-wüstite (IW) buffer at <span class="hlt">pressure</span> and temperature [ΔIW (P,T)]. This equilibrium is considered across a wide range of <span class="hlt">pressures</span> and temperatures, including up to the liquidus temperature of peridotite (4,000 K at 50 GPa). Application of ΔIW (ratio) to metal-silicate experiments can be three or four orders of magnitude different from ΔIW (P,T) values calculated using free energy and activity modeling. We will also use this approach to consider the variation in oxygen fugacity in a magma ocean scenario for various thermal structures for the early Earth: hot liquidus <span class="hlt">gradient</span>, 100 °C below the liquidus, hot and cool adiabatic <span class="hlt">gradients</span>, and a cool subsolidus adiabat. The results are used to assess the effect of increasing P and T, changing silicate composition during accretion, and related to current models for accretion and core formation in the Earth. The fO2 in a deep magma ocean scenario may become lower relative to the IW buffer at hotter and deeper conditions, which could include metal entrainment scenarios. Therefore, fO2 may evolve from high to low fO2 during Earth (and other differentiated bodies) accretion. Any modeling of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150023002','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150023002"><span>Implicit Large-Eddy Simulations of Zero-<span class="hlt">Pressure</span> <span class="hlt">Gradient</span>, Turbulent Boundary Layer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sekhar, Susheel; Mansour, Nagi N.</p> <p>2015-01-01</p> <p>A set of direct simulations of zero-<span class="hlt">pressure</span> <span class="hlt">gradient</span>, turbulent boundary layer flows are conducted using various span widths (62-630 wall units), to document their influence on the generated turbulence. The FDL3DI code that solves compressible Navier-Stokes equations using high-order compact-difference scheme and filter, with the standard recycling/rescaling method of turbulence generation, is used. Results are analyzed at two different Re values (500 and 1,400), and compared with spectral DNS data. They show that a minimum span width is required for the mere initiation of numerical turbulence. Narrower domains ((is) less than 100 w.u.) result in relaminarization. Wider spans ((is) greater than 600 w.u.) are required for the turbulent statistics to match reference DNS. The upper-wall boundary condition for this setup spawns marginal deviations in the mean velocity and Reynolds stress profiles, particularly in the buffer region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JaJAP..57a02A1Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JaJAP..57a02A1Y"><span>Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-<span class="hlt">pressure</span> water <span class="hlt">vapor</span> bubbles?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yui, Hiroharu; Banno, Motohiro</p> <p>2018-01-01</p> <p>In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water <span class="hlt">vapor</span> bubbles transiently generated in the solution under atmospheric <span class="hlt">pressure</span>. To clarify how SP emerges in water <span class="hlt">vapor</span> bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water <span class="hlt">vapor</span> bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol1/pdf/CFR-2012-title46-vol1-sec39-20-11.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title46-vol1/pdf/CFR-2012-title46-vol1-sec39-20-11.pdf"><span>46 CFR 39.20-11 - <span class="hlt">Vapor</span> overpressure and vacuum protection-TB/ALL.</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>...-11 Section 39.20-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS <span class="hlt">VAPOR</span> CONTROL SYSTEMS Design and Equipment § 39.20-11 <span class="hlt">Vapor</span> overpressure and vacuum protection—TB/ALL. (a) The cargo... connected to the <span class="hlt">vapor</span> collection system does not exceed: (i) The maximum design working <span class="hlt">pressure</span> for the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol1/pdf/CFR-2011-title46-vol1-sec39-20-11.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title46-vol1/pdf/CFR-2011-title46-vol1-sec39-20-11.pdf"><span>46 CFR 39.20-11 - <span class="hlt">Vapor</span> overpressure and vacuum protection-TB/ALL.</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>...-11 Section 39.20-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS <span class="hlt">VAPOR</span> CONTROL SYSTEMS Design and Equipment § 39.20-11 <span class="hlt">Vapor</span> overpressure and vacuum protection—TB/ALL. (a) The cargo... connected to the <span class="hlt">vapor</span> collection system does not exceed: (i) The maximum design working <span class="hlt">pressure</span> for the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol1/pdf/CFR-2010-title46-vol1-sec39-20-11.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title46-vol1/pdf/CFR-2010-title46-vol1-sec39-20-11.pdf"><span>46 CFR 39.20-11 - <span class="hlt">Vapor</span> overpressure and vacuum protection-TB/ALL.</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>...-11 Section 39.20-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS <span class="hlt">VAPOR</span> CONTROL SYSTEMS Design and Equipment § 39.20-11 <span class="hlt">Vapor</span> overpressure and vacuum protection—TB/ALL. (a) The cargo... connected to the <span class="hlt">vapor</span> collection system does not exceed: (i) The maximum design working <span class="hlt">pressure</span> for the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22413010-atmospheric-pressure-synthesis-photoluminescent-hybrid-materials-sequential-organometallic-vapor-infiltration-polyethylene-terephthalate-fibers','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22413010-atmospheric-pressure-synthesis-photoluminescent-hybrid-materials-sequential-organometallic-vapor-infiltration-polyethylene-terephthalate-fibers"><span>Atmospheric <span class="hlt">pressure</span> synthesis of photoluminescent hybrid materials by sequential organometallic <span class="hlt">vapor</span> infiltration into polyethylene terephthalate fibers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Akyildiz, Halil I.; Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695; Mousa, Moataz Bellah M.</p> <p></p> <p>Exposing a polymer to sequential organometallic <span class="hlt">vapor</span> infiltration (SVI) under low <span class="hlt">pressure</span> conditions can significantly modify the polymer's chemical, mechanical, and optical properties. We demonstrate that SVI of trimethylaluminum into polyethylene terephthalate (PET) can also proceed readily at atmospheric <span class="hlt">pressure</span>, and at 60 °C the extent of reaction determined by mass uptake is independent of <span class="hlt">pressure</span> between 2.5 Torr and 760 Torr. At 120 °C, however, the mass gain is 50% larger at 2.5 Torr relative to that at 760 Torr, indicating that the precursor diffusion in the chamber and fiber matrix decreases at higher source <span class="hlt">pressure</span>. Mass gain decreases, in general, as the SVI processmore » temperature increases both at 2.5 Torr and 760 Torr attributed to the faster reaction kinetics forming a barrier layer, which prevents further diffusion of the reactive species. The resulting PET/Al-O{sub x} product shows high photoluminescence compared to untreated fibers. A physical mask on the polymer during infiltration at 760 Torr is replicated in the underlying polymer, producing an image in the polymer that is visible under UV illumination. Because of the reduced precursor diffusivity during exposure at 760 Torr, the image shows improved resolution compared to SVI performed under typical 2.5 Torr conditions.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DFD.G6001B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DFD.G6001B"><span>Acoustically-Enhanced Direct Contact <span class="hlt">Vapor</span> Bubble Condensation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boziuk, Thomas; Smith, Marc; Glezer, Ari</p> <p>2017-11-01</p> <p>Rate-limited, direct contact <span class="hlt">vapor</span> condensation of <span class="hlt">vapor</span> bubbles that are formed by direct steam injection through a nozzle in a quiescent subcooled liquid bath is accelerated using ultrasonic (MHz-range) actuation. A submerged, low power actuator produces an acoustic beam whose radiation <span class="hlt">pressure</span> deforms the liquid-<span class="hlt">vapor</span> interface, leading to the formation of a liquid spear that penetrates the <span class="hlt">vapor</span> bubble to form a <span class="hlt">vapor</span> torus with a significantly larger surface area and condensation rate. Ultrasonic focusing along the spear leads to the ejection of small, subcooled droplets through the <span class="hlt">vapor</span> volume that impact the <span class="hlt">vapor</span>-liquid interface and further enhance the condensation. High-speed Schlieren imaging of the formation and collapse of the <span class="hlt">vapor</span> bubbles in the absence and presence of actuation shows that the impulse associated with the collapse of the toroidal volume leads to the formation of a turbulent vortex ring in the liquid phase. Liquid motions near the condensing <span class="hlt">vapor</span> volume are investigated in the absence and presence of acoustic actuation using high-magnification PIV and show the evolution of a liquid jet through the center of the condensing toroidal volume and the formation and advection of vortex ring structures whose impulse appear to increase with temperature difference between the liquid and <span class="hlt">vapor</span> phases. High-speed image processing is used to assess the effect of the actuation on the temporal and spatial variations in the characteristic scales and condensation rates of the <span class="hlt">vapor</span> bubbles.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090042611','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090042611"><span>Optimal Disturbances in Boundary Layers Subject to Streamwise <span class="hlt">Pressure</span> <span class="hlt">Gradient</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tumin, Anatoli; Ashpis, David E.</p> <p>2003-01-01</p> <p>Laminar-turbulent transition in shear flows is still an enigma in the area of fluid mechanics. The conventional explanation of the phenomenon is based on the instability of the shear flow with respect to infinitesimal disturbances. The conventional hydrodynamic stability theory deals with the analysis of normal modes that might be unstable. The latter circumstance is accompanied by an exponential growth of the disturbances that might lead to laminar-turbulent transition. Nevertheless, in many cases, the transition scenario bypasses the exponential growth stage associated with the normal modes. This type of transition is called bypass transition. An understanding of the phenomenon has eluded us to this day. One possibility is that bypass transition is associated with so-called algebraic (non-modal) growth of disturbances in shear flows. In the present work, an analysis of the optimal disturbances/streamwise vortices associated with the transient growth mechanism is performed for boundary layers in the presence of a streamwise <span class="hlt">pressure</span> <span class="hlt">gradient</span>. The theory will provide the optimal spacing of the control elements in the spanwise direction and their placement in the streamwise direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JAP...120j5701K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JAP...120j5701K"><span>Correlation between mobility collapse and carbon impurities in Si-doped GaN grown by low <span class="hlt">pressure</span> metalorganic chemical <span class="hlt">vapor</span> deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaess, Felix; Mita, Seiji; Xie, Jingqiao; Reddy, Pramod; Klump, Andrew; Hernandez-Balderrama, Luis H.; Washiyama, Shun; Franke, Alexander; Kirste, Ronny; Hoffmann, Axel; Collazo, Ramón; Sitar, Zlatko</p> <p>2016-09-01</p> <p>In the low doping range below 1 × 1017 cm-3, carbon was identified as the main defect attributing to the sudden reduction of the electron mobility, the electron mobility collapse, in n-type GaN grown by low <span class="hlt">pressure</span> metalorganic chemical <span class="hlt">vapor</span> deposition. Secondary ion mass spectroscopy has been performed in conjunction with C concentration and the thermodynamic Ga supersaturation model. By controlling the ammonia flow rate, the input partial <span class="hlt">pressure</span> of Ga precursor, and the diluent gas within the Ga supersaturation model, the C concentration in Si-doped GaN was controllable from 6 × 1019 cm-3 to values as low as 2 × 1015 cm-3. It was found that the electron mobility collapsed as a function of free carrier concentration, once the Si concentration closely approached the C concentration. Lowering the C concentration to the order of 1015 cm-3 by optimizing Ga supersaturation achieved controllable free carrier concentrations down to 5 × 1015 cm-3 with a peak electron mobility of 820 cm2/V s without observing the mobility collapse. The highest electron mobility of 1170 cm2/V s was obtained even in metalorganic <span class="hlt">vapor</span> deposition-grown GaN on sapphire substrates by optimizing growth parameters in terms of Ga supersaturation to reduce the C concentration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790025267','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790025267"><span>Survey and bibliography on attainment of laminar flow control in air using <span class="hlt">pressure</span> <span class="hlt">gradient</span> and suction, volume 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bushnell, D. M.; Tuttle, M. H.</p> <p>1979-01-01</p> <p>A survey was conducted and a bibliography compiled on attainment of laminar flow in air through the use of favorable <span class="hlt">pressure</span> <span class="hlt">gradient</span> and suction. This report contains the survey, summaries of data for both ground and flight experiments, and abstracts of referenced reports. Much early information is also included which may be of some immediate use as background material for LFC applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970023154','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970023154"><span>Mass Flux of ZnSe by Physical <span class="hlt">Vapor</span> Transport</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sha, Yi-Gao; Su, Ching-Hua; Palosz, W.; Volz, M. P.; Gillies, D. C.; Szofran, F. R.; Lehoczky, S. L.; Liu, Hao-Chieh; Brebrick, R. F.</p> <p>1995-01-01</p> <p>Mass fluxes of ZnSe by physical <span class="hlt">vapor</span> transport (PVT) were measured in the temperature range of 1050 to 1160 C using an in-situ dynamic technique. The starting materials were either baked out or distilled under vacuum to obtain near-congruently subliming compositions. Using an optical absorption technique Zn and Se, were found to be the dominant <span class="hlt">vapor</span> species. Partial <span class="hlt">pressures</span> of Zn and Se, over the starting materials at temperatures between 960 and 1140 C were obtained by measuring the optical densities of the <span class="hlt">vapor</span> phase at the wavelengths of 2138, 3405, 3508, 3613, and 3792 A. The amount and composition of the residual gas inside the experimental ampoules were measured after the run using a total <span class="hlt">pressure</span> gauge. For the first time, the experimentally determined partial <span class="hlt">pressures</span> of Zn and Se, and the amount and composition of the residual gas were used in a one-dimensional diffusion limited analysis of the mass transport rates for a PVT system. Reasonable agreement between the experimental and theoretical results was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29439881','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29439881"><span>Prospective assessment of the frequency of low <span class="hlt">gradient</span> severe aortic stenosis with preserved left ventricular ejection fraction: Critical impact of aortic flow misalignment and <span class="hlt">pressure</span> recovery phenomenon.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ringle, Anne; Castel, Anne-Laure; Le Goffic, Caroline; Delelis, François; Binda, Camille; Bohbot, Yohan; Ennezat, Pierre Vladimir; Guerbaai, Raphaëlle A; Levy, Franck; Vincentelli, André; Graux, Pierre; Tribouilloy, Christophe; Maréchaux, Sylvestre</p> <p>2018-02-10</p> <p>The frequency of paradoxical low-<span class="hlt">gradient</span> severe aortic stenosis (AS) varies widely across studies. The impact of misalignment of aortic flow and <span class="hlt">pressure</span> recovery phenomenon on the frequency of low-<span class="hlt">gradient</span> severe AS with preserved left ventricular ejection fraction (LVEF) has not been evaluated in prospective studies. To investigate prospectively the impact of aortic flow misalignment by Doppler and lack of <span class="hlt">pressure</span> recovery phenomenon correction on the frequency of low-<span class="hlt">gradient</span> (LG) severe aortic stenosis (AS) with preserved LVEF. Aortic jet velocities and mean <span class="hlt">pressure</span> <span class="hlt">gradient</span> (MPG) were obtained by interrogating all windows in 68 consecutive patients with normal LVEF and severe AS (aortic valve area [AVA] ≤1cm 2 ) on the basis of the apical imaging window alone (two-dimensional [2D] apical approach). Patients were classified as having LG or high-<span class="hlt">gradient</span> (HG) AS according to MPG <40mmHg or ≥40mmHg, and normal flow (NF) or low flow (LF) according to stroke volume index >35mL/m 2 or ≤35mL/m 2 , on the basis of the 2D apical approach, the multiview approach (multiple windows evaluation) and AVA corrected for <span class="hlt">pressure</span> recovery. The proportion of LG severe AS was 57% using the 2D apical approach alone. After the multiview approach and correction for <span class="hlt">pressure</span> recovery, the proportion of LG severe AS decreased from 57% to 13% (LF-LG severe AS decreased from 23% to 3%; NF-LG severe AS decreased from 34% to 10%). As a result, 25% of patients were reclassified as having HG severe AS (AVA ≤1cm 2 and MPG ≥40mmHg) and 19% as having moderate AS. Hence, 77% of patients initially diagnosed with LG severe AS did not have "true" LG severe AS when the multiview approach and the <span class="hlt">pressure</span> recovery phenomenon correction were used. Aortic flow misevaluation, resulting from lack of use of multiple windows evaluation and <span class="hlt">pressure</span> recovery phenomenon correction, accounts for a large proportion of incorrectly graded AS and considerable overestimation of the frequency of LG</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhRvE..84e5401S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhRvE..84e5401S"><span>Electrical Breakdown in Water <span class="hlt">Vapor</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Škoro, N.; Marić, D.; Malović, G.; Graham, W. G.; Petrović, Z. Lj.</p> <p>2011-11-01</p> <p>In this paper investigations of the voltage required to break down water <span class="hlt">vapor</span> are reported for the region around the Paschen minimum and to the left of it. In spite of numerous applications of discharges in biomedicine, and recent studies of discharges in water and <span class="hlt">vapor</span> bubbles and discharges with liquid water electrodes, studies of the basic parameters of breakdown are lacking. Paschen curves have been measured by recording voltages and currents in the low-current Townsend regime and extrapolating them to zero current. The minimum electrical breakdown voltage for water <span class="hlt">vapor</span> was found to be 480 V at a <span class="hlt">pressure</span> times electrode distance (pd) value of around 0.6 Torr cm (˜0.8 Pa m). The present measurements are also interpreted using (and add additional insight into) the developing understanding of relevant atomic and particularly surface processes associated with electrical breakdown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26210018','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26210018"><span>Measurements of octanol-air partition coefficients, <span class="hlt">vapor</span> <span class="hlt">pressures</span> and <span class="hlt">vaporization</span> enthalpies of the (E) and (Z) isomers of the 2-ethylhexyl 4-methoxycinnamate as parameters of environmental impact assessment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pegoraro, César N; Chiappero, Malisa S; Montejano, Hernán A</p> <p>2015-11-01</p> <p>2-Ethylhexyl 4-methoxycinnamate is one of the UVB blocking agents more widely used in a variety of industrial fields. There are more than one hundred industrial suppliers worldwide. Given the enormous annual consumption of octinoxate, problems that arise due to the accumulation of this compound in nature should be taken into consideration. The GC-RT was used in this work with the aim of determining the <span class="hlt">vapor</span> <span class="hlt">pressure</span>, enthalpies of <span class="hlt">vaporization</span> and octanol-air partition coefficient, for the BBP, DOP, E- and Z-EHMC esters. The results showed that Z-EHMC is almost five times more volatile than E-EHMC. Moreover, BBP, Z-EHMC and E-EHMC can be classified as substances with a relatively low mobility since they lie within the range of 8<logKOA<10 and -4<log(PL/Pa)<-2, while DOP lies in the range of logKOA>10 and log(PL/Pa)<-4, therefore, a low mobility can be expected. From these parameters, their particle-bound fraction and gas-particle partition coefficient were also derived. Copyright © 2015 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eric.ed.gov/?q=gas+AND+liquid&id=EJ1088234','ERIC'); return false;" href="https://eric.ed.gov/?q=gas+AND+liquid&id=EJ1088234"><span>Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on <span class="hlt">Pressure</span>-Temperature Diagrams of a Mixed Gas Involving Liquid-<span class="hlt">Vapor</span> Equilibrium</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Yoshikawa, Masahiro; Koga, Nobuyoshi</p> <p>2016-01-01</p> <p>This study focuses on students' understandings of a liquid-gas system with liquid-<span class="hlt">vapor</span> equilibrium in a closed system using a <span class="hlt">pressure</span>-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23701708','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23701708"><span>Stomatal responses to changes in <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit reflect tissue-specific differences in hydraulic conductance.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ocheltree, T W; Nippert, J B; Prasad, P V V</p> <p>2014-01-01</p> <p>The <span class="hlt">vapor</span> <span class="hlt">pressure</span> deficit (D) of the atmosphere can negatively affect plant growth as plants reduce stomatal conductance to water <span class="hlt">vapor</span> (g(wv)) in response to increasing D, limiting the ability of plants to assimilate carbon. The sensitivity of g(wv) to changes in D varies among species and has been correlated with the hydraulic conductance of leaves (K(leaf) ), but the hydraulic conductance of other tissues has also been implicated in plant responses to changing D. Among the 19 grass species, we found that K(leaf) was correlated with the hydraulic conductance of large longitudinal veins (K(lv), r(2) = 0.81), but was not related to K(root) (r(2) = 0.01). Stomatal sensitivity to D was correlated with K(leaf) relative to total leaf area (r(2) = 0.50), and did not differ between C3 and C4 species. Transpiration (E) increased in response to D, but 8 of the 19 plants showed a decline in E at high D, indicative of an 'apparent feedforward' response. For these individuals, E began to decline at lower values of D in plants with low K(root) (r(2) = 0.72). These results show the significance of both leaf and root hydraulic conductance as drivers of plant responses to evaporative demand. © 2013 John Wiley & Sons Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3778006','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3778006"><span>Selective <span class="hlt">Pressure</span> along a Latitudinal <span class="hlt">Gradient</span> Affects Subindividual Variation in Plants</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sobral, Mar; Guitián, José; Guitián, Pablo; Larrinaga, Asier R.</p> <p>2013-01-01</p> <p>Individual plants produce repeated structures such as leaves, flowers or fruits, which, although belonging to the same genotype, are not phenotypically identical. Such subindividual variation reflects the potential of individual genotypes to vary with micro-environmental conditions. Furthermore, variation in organ traits imposes costs to foraging animals such as time, energy and increased predation risk. Therefore, animals that interact with plants may respond to this variation and affect plant fitness. Thus, phenotypic variation within an individual plant could be, in part, an adaptive trait. Here we investigated this idea and we found that subindividual variation of fruit size of Crataegus monogyna, in different populations throughout the latitudinal <span class="hlt">gradient</span> in Europe, was explained at some extent by the selective <span class="hlt">pressures</span> exerted by seed-dispersing birds. These findings support the hypothesis that within-individual variation in plants is an adaptive trait selected by interacting animals which may have important implications for plant evolution. PMID:24069297</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/868592','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/868592"><span>Low temperature photochemical <span class="hlt">vapor</span> deposition of alloy and mixed metal oxide films</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Liu, David K.</p> <p>1992-01-01</p> <p>Method and apparatus for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor <span class="hlt">vapor(s</span>) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor <span class="hlt">vapor(s</span>) is formed by <span class="hlt">vaporization</span> of one or more precursor materials, where the <span class="hlt">vaporization</span> temperature(s) is selected to control the ratio of concentration of metals present in the precursor <span class="hlt">vapor(s</span>) and/or the total precursor <span class="hlt">vapor</span> <span class="hlt">pressure</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/7233744','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/7233744"><span>Low temperature photochemical <span class="hlt">vapor</span> deposition of alloy and mixed metal oxide films</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Liu, D.K.</p> <p>1992-12-15</p> <p>Method and apparatus are described for formation of an alloy thin film, or a mixed metal oxide thin film, on a substrate at relatively low temperatures. Precursor <span class="hlt">vapor(s</span>) containing the desired thin film constituents is positioned adjacent to the substrate and irradiated by light having wavelengths in a selected wavelength range, to dissociate the gas(es) and provide atoms or molecules containing only the desired constituents. These gases then deposit at relatively low temperatures as a thin film on the substrate. The precursor <span class="hlt">vapor(s</span>) is formed by <span class="hlt">vaporization</span> of one or more precursor materials, where the <span class="hlt">vaporization</span> temperature(s) is selected to control the ratio of concentration of metals present in the precursor <span class="hlt">vapor(s</span>) and/or the total precursor <span class="hlt">vapor</span> <span class="hlt">pressure</span>. 7 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title33-vol2/pdf/CFR-2014-title33-vol2-sec154-2103.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title33-vol2/pdf/CFR-2014-title33-vol2-sec154-2103.pdf"><span>33 CFR 154.2103 - Facility requirements for vessel <span class="hlt">vapor</span> overpressure and vacuum protection.</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>2014-07-01</p> <p>... HAZARDOUS MATERIAL IN BULK Marine <span class="hlt">Vapor</span> Control Systems Transfer Facilities-Vcs Design and Installation... rate, unless there is experimental data for actual <span class="hlt">vapor</span> growth for turbulent transferring under the... <span class="hlt">vapor</span> growth. (b) A facility VCS must be designed to prevent the <span class="hlt">pressure</span> in a vessel's cargo tanks from...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19323864','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19323864"><span>Social class-related <span class="hlt">gradient</span> in the association of skeletal growth with blood <span class="hlt">pressure</span> among adolescent boys 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>Rao, Shobha; Apte, Priti</p> <p>2009-12-01</p> <p>In view of the fact that height differences between socio-economic groups are apparent early in childhood, it is of interest to examine whether skeletal growth is reflective of the social class <span class="hlt">gradient</span> in CVD risk. The present study examined blood <span class="hlt">pressure</span> levels, adiposity and growth of adolescent boys from high and low social classes. In a cross-sectional study, skeletal growth (height and sitting height), adiposity (weight, BMI and body fat) and blood <span class="hlt">pressure</span> levels of the adolescents were measured. Pune, India. Adolescent schoolboys (9-16 years) from high socio-economic (HSE; n 1146) and low socio-economic (LSE; n 932) class. LSE boys were thin, short and undernourished (mean BMI: 15.5 kg/m2 v. 19.3 kg/m2 in HSE boys, P = 0.00). Social <span class="hlt">gradient</span> was revealed in differing health risks. The prevalence of high systolic blood <span class="hlt">pressure</span> (HSBP) was high in HSE class (10.5 % v. 2.7 % in LSE class, P = 0.00) and was associated with adiposity, while the prevalence of high diastolic blood <span class="hlt">pressure</span> (HDBP) was high in LSE class (9.8 % v. 7.0 % in HSE class, P = 0.00) and had only a weak association with adiposity. Despite this, lower ratio of leg length to height was associated with significantly higher respective health risks, i.e. for HDBP in LSE class (OR = 1.99, 95 % CI 1.14, 3.47) and for HSBP in HSE class (OR = 1.69, 95 % CI 1.02, 2.77). As stunting in childhood is a major problem in India and Asia, the leg length to height indicator needs to be validated in different populations to understand CVD risks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1439957-vaporization-behavior-alkyl-diphenyl-ether-commercial-lubricant','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1439957-vaporization-behavior-alkyl-diphenyl-ether-commercial-lubricant"><span><span class="hlt">Vaporization</span> behavior of an alkyl diphenyl ether and a commercial lubricant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>McMurray, Jake W.; Frame, Barbara J.; Voit, Stewart L.</p> <p></p> <p>The equilibrium <span class="hlt">vapor</span> <span class="hlt">pressure</span> as a function of temperature for an alkyl diphenyl ether with a <span class="hlt">vaporization</span> coefficient significantly smaller than unity was characterized using the combined Langmuir free evaporation and mass loss Knudsen effusion technique. Results are compared using different cell designs and discrepancies, difficulties, and complications are discussed. In conclusion, the enthalpy and entropy of <span class="hlt">vaporization</span> are estimated using the average temperature of the measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1439957-vaporization-behavior-alkyl-diphenyl-ether-commercial-lubricant','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1439957-vaporization-behavior-alkyl-diphenyl-ether-commercial-lubricant"><span><span class="hlt">Vaporization</span> behavior of an alkyl diphenyl ether and a commercial lubricant</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>McMurray, Jake W.; Frame, Barbara J.; Voit, Stewart L.</p> <p>2018-05-24</p> <p>The equilibrium <span class="hlt">vapor</span> <span class="hlt">pressure</span> as a function of temperature for an alkyl diphenyl ether with a <span class="hlt">vaporization</span> coefficient significantly smaller than unity was characterized using the combined Langmuir free evaporation and mass loss Knudsen effusion technique. Results are compared using different cell designs and discrepancies, difficulties, and complications are discussed. In conclusion, the enthalpy and entropy of <span class="hlt">vaporization</span> are estimated using the average temperature of the measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title33-vol2/pdf/CFR-2014-title33-vol2-sec154-2108.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title33-vol2/pdf/CFR-2014-title33-vol2-sec154-2108.pdf"><span>33 CFR 154.2108 - <span class="hlt">Vapor</span>-moving devices.</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>2014-07-01</p> <p>...) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Marine <span class="hlt">Vapor</span> Control Systems Transfer... vibration; (4) Low lube oil level; (5) Low lube oil <span class="hlt">pressure</span>; and (6) Excessive shaft bearing temperature...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990PhDT........64L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990PhDT........64L"><span>The Chemical <span class="hlt">Vapor</span> Deposition of Thin Metal Oxide Films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laurie, Angus Buchanan</p> <p>1990-01-01</p> <p>Chemical <span class="hlt">vapor</span> deposition (CVD) is an important method of preparing thin films of materials. Copper (II) oxide is an important p-type semiconductor and a major component of high T_{rm c} superconducting oxides. By using a volatile copper (II) chelate precursor, copper (II) bishexafluoroacetylacetonate, it has been possible to prepare thin films of copper (II) oxide by low temperature normal <span class="hlt">pressure</span> metalorganic chemical <span class="hlt">vapor</span> deposition. In the metalorganic CVD (MOCVD) production of oxide thin films, oxygen gas saturated with water <span class="hlt">vapor</span> has been used mainly to reduce residual carbon and fluorine content. This research has investigated the influence of water-saturated oxygen on the morphology of thin films of CuO produced by low temperature chemical <span class="hlt">vapor</span> deposition onto quartz, magnesium oxide and cubic zirconia substrates. ZnO is a useful n-type semiconductor material and is commonly prepared by the MOCVD method using organometallic precursors such as dimethyl or diethylzinc. These compounds are difficult to handle under atmospheric conditions. In this research, thin polycrystalline films of zinc oxide were grown on a variety of substrates by normal <span class="hlt">pressure</span> CVD using a zinc chelate complex with zinc(II) bishexafluoroacetylacetonate dihydrate (Zn(hfa)_2.2H _2O) as the zinc source. Zn(hfa) _2.2H_2O is not moisture - or air-sensitive and is thus more easily handled. By operating under reduced-<span class="hlt">pressure</span> conditions (20-500 torr) it is possible to substantially reduce deposition times and improve film quality. This research has investigated the reduced-<span class="hlt">pressure</span> CVD of thin films of CuO and ZnO. Sub-micron films of tin(IV) oxide (SnO _2) have been grown by normal <span class="hlt">pressure</span> CVD on quartz substrates by using tetraphenyltin (TPT) as the source of tin. All CVD films were characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DFDR25008B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DFDR25008B"><span>The latent heat of <span class="hlt">vaporization</span> of supercritical fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banuti, Daniel; Raju, Muralikrishna; Hickey, Jean-Pierre; Ihme, Matthias</p> <p>2016-11-01</p> <p>The enthalpy of <span class="hlt">vaporization</span> is the energy required to overcome intermolecular attractive forces and to expand the fluid volume against the ambient <span class="hlt">pressure</span> when transforming a liquid into a gas. It diminishes for rising <span class="hlt">pressure</span> until it vanishes at the critical point. Counterintuitively, we show that a latent heat is in fact also required to heat a supercritical fluid from a liquid to a gaseous state. Unlike its subcritical counterpart, the supercritical pseudoboiling transition is spread over a finite temperature range. Thus, in addition to overcoming intermolecular attractive forces, added energy simultaneously heats the fluid. Then, considering a transition from a liquid to an ideal gas state, we demonstrate that the required enthalpy is invariant to changes in <span class="hlt">pressure</span> for 0 < p < 3pcr . This means that the classical <span class="hlt">pressure</span>-dependent latent heat is merely the equilibrium part of the phase transition. The reduction at higher <span class="hlt">pressures</span> is compensated by an increase in a nonequilibrium latent heat required to overcome residual intermolecular forces in the real fluid <span class="hlt">vapor</span> during heating. At supercritical <span class="hlt">pressures</span>, all of the transition occurs at non-equilibrium; for p -> 0 , all of the transition occurs at equilibrium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/71675','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/71675"><span>Numerical simulation of water injection into <span class="hlt">vapor</span>-dominated reservoirs</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Pruess, K.</p> <p>1995-01-01</p> <p>Water injection into <span class="hlt">vapor</span>-dominated reservoirs is a means of condensate disposal, as well as a reservoir management tool for enhancing energy recovery and reservoir life. We review different approaches to modeling the complex fluid and heat flow processes during injection into <span class="hlt">vapor</span>-dominated systems. <span class="hlt">Vapor</span> <span class="hlt">pressure</span> lowering, grid orientation effects, and physical dispersion of injection plumes from reservoir heterogeneity are important considerations for a realistic modeling of injection effects. An example of detailed three-dimensional modeling of injection experiments at The Geysers is given.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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