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1

Polynomial fits to saturation vapor pressure  

NASA Astrophysics Data System (ADS)

Eighth- and sixth-order polynomial fits are presented for Wexler's and Hyland-Wexler's saturation-vapor-pressure (SVP) expressions over water and ice. Fits to the temperature derivative of SVP are also given. The polynomials are shown to provide good global fits amenable to vectorized implementation on modern computers. When implemented on a CRAY-YMP computer, the polynomial fits proposed here are shown to be more efficient than other approximations in the literature.

Flatau, Piotr J.; Walko, Robert L.; Cotton, William R.

1992-12-01

2

Studying Pressure of Saturated Vapors of Some Semiconductors by Means of Radioactive Isotopes.  

National Technical Information Service (NTIS)

The object was to study the pressure of saturated vapors in a number of semiconductor compounds and solutions and to clarify certain processes which occur during evaporation. The most exact determination of saturated vapor pressure is obtained by using ra...

M. G. Shakhtakhtinskii

1973-01-01

3

Pressure dependence of the small-signal gain and saturation intensity of a copper vapor laser.  

PubMed

The small-signal gain coefficient and the saturation intensity of a copper vapor laser have been measured for both 510.6- and 578.2-nm transitions through the implementation of a discharge driven oscillator-amplifier configuration. Pressure dependence of the gain and saturation property of the laser has been investigated. PMID:12617218

Behrouzinia, Saeid; Sadighi, Rasool; Parvin, Parviz

2003-02-20

4

a Property of the Saturated Vapor Pressure:. Results from Equations of State  

NASA Astrophysics Data System (ADS)

Experimentally, a maximum point in the curve of the saturated property ?=(1-Tr)Pr versus the saturated temperature was postulated (High Temp.-High Press. 26 (1994) 427). Here, Tr is the saturated temperature reduced by the critical temperature and Pr is the saturated pressure reduced by the critical pressure. Later, this behavior was applied to assure the saturated vapor pressure critical amplitudes (Appl. Phys. Lett. 90 (2007) 141905). In this paper, we indicate that theory of equation of state (EOS) can predict this maximum point. The EOSs we study are the combinations of the hard sphere repulsions and some normally used attractions such as the Redlich-Kwong attraction. We find the EOSs with Redlich-Kwong attractive terms give out the results in the experimental range.

Tian, Jianxiang; Jiang, Hua; Xu, Yi

5

The Observed Properties of Liquid Helium at the Saturated Vapor Pressure  

Microsoft Academic Search

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

Russell J. Donnelly; Carlo F. Barenghi

1998-01-01

6

Nomograph for the Determination of the Pressure of Saturated Vapors, Density and Viscosity of Concentrated Fuming Nitric Acid.  

National Technical Information Service (NTIS)

Previous investigations of the changes in the properties of solutions of nitrogen tetroxide in concentrated nitric acid made it possible to construct nomographs for the calculation of the pressure of saturated vapors, density, and viscosity in the studied...

E. I. Perlov M. M. Karavaev

1972-01-01

7

Rapid thermogravimetric measurements of boiling points and vapor pressure of saturated medium- and long-chain triglycerides.  

PubMed

In developing compositional models for biomass-based diesel fuel extenders, volatility properties of medium- and long-chain saturated triglycerides are essential to predict the impact of low levels of these compounds in mixtures with short-chain triglycerides. A thermogravimetric analysis (TGA) method for rapid measurement of boiling points and vapor pressure was used to obtain data for four pure medium- and long-chain triglycerides. Normal boiling points at 1 atm and the temperature dependence of vapor pressure from 760 mm down to 25 mm Hg were obtained for trilaurin (C12:0), trimyristin (C14:0), tripalmitin (C16:0), and tristearin (C18:0). The data showed good agreement with the Clausius-Clapeyron model for temperature dependence of vapor pressure up to 1 atm pressure. The results of this study were consistent with those obtained using differential scanning calorimetry (DSC) and with data previously reported for reduced pressure. PMID:12137273

Goodrum, John W; Geller, Daniel P

2002-08-01

8

The temperature dependence of mercury saturated vapor pressure over the whole range of its liquid state  

NASA Astrophysics Data System (ADS)

The Boltzmann distribution with normalization with respect to the boiling point was used to calculate the temperature dependence of vapor pressure, which included the temperature and heat of boiling only. A refined equation of mercury vaporizability with mutually consistent characteristics such as vapor pressure and the temperature and heat of boiling was obtained. The equation correctly described this dependence over the whole liquid state range, including the critical point.

Turdukozhaeva, A. M.

2012-04-01

9

Rapid thermogravimetric measurements of boiling points and vapor pressure of saturated medium- and long-chain triglycerides  

Microsoft Academic Search

In developing compositional models for biomass-based diesel fuel extenders, volatility properties of medium- and long-chain saturated triglycerides are essential to predict the impact of low levels of these compounds in mixtures with short-chain triglycerides. A thermogravimetric analysis (TGA) method for rapid measurement of boiling points and vapor pressure was used to obtain data for four pure medium- and long-chain triglycerides.

John W. Goodrum; Daniel P. Geller

2002-01-01

10

Evaluation of saturation vapor pressure over hypersaline water bodies at the southern edge of the Dead Sea, Jordan  

SciTech Connect

The activity coefficient and saturation vapor pressure for hypersaline solutions located at the southern edge of the Dead Sea are computed analytically. The collected data consist of temperature and evaporation rates measured for a freshwater pan and three other hypersaline solutions with specific gravities of 1.26, 1.31, and 1.34, respectively. The activity coefficients of the three saline pans were computed after accounting for the effect of buoyancy, which was included in the computations because of consistently large, positive virtual temperature differences between the saline pans and the ambient air. The ratios of saline to fresh pan evaporation (Es/Ef: the [alpha] ratio) of the present study are also compared to data reported for the Bonneville Salt Brines, Utah. It is found that the a ratios of the present study, although conducted over an extended period of time, are larger than those reported for the Bonneville Brines. Results of the present study imply that evaporation from the various brine-concentrated, shallow lakes at the southern edge of the Dead Sea is likely to proceed during the entire year, and water vapor deposition from the atmosphere, due to an inverted vapor pressure, is less likely to occur particularly for brines with specific gravities of less than 1.3.

Oroud, I.M. (Muta'h Univ., Al-Kerak (Jordan))

1994-12-01

11

Electrical conductivity measurements of aqueous boric acid at 25--350{degree}C at saturation vapor pressure. Final report  

SciTech Connect

Electrical conductance measurements of aqueous boric acid solutions (15-110 g/kg-H{sub 2}O {equivalent_to} 0.251--1.815 mol/kg-H{sub 2}O) were measured over the temperature range 25 to 75 C at saturation vapor pressures in glass cells with parallel platinum electrodes. Sixteen series of measurements were made involving three samples of boric acid from different sources. Conductance measurements were also made at 15.5 and 30.5 g/kg-H{sub 2}O over the temperature range 100 to 350 C at 50 C intervals with a metallic cell fitted with concentric platinum electrodes. The specific conductances of H{sub 3}BO{sub 3} (aq)were calculated after correction for the conductance of the solvent (water) and are tabulated in this report. At the specific conditions requested in the project description, namely a concentration of 110 g/kg-H{sub 2}O and 65 C, the specific conductance of boric acid is 293.2 {+-} 1.8 microSiemens/cm based on duplicate measurements of four independent solutions. The results from these tests will be utilized by the Tokamak Physics Experimental Project (TPX).

Ho, P.C.; Palmer, D.A.

1995-09-01

12

Progress of serpentinization in olivine-H2O system at 250 C and vapor-saturated pressure  

NASA Astrophysics Data System (ADS)

Fluids play a crucial role in global-scale mass transfer, metamorphism, volcanism, and seismic processes in subduction zones. Serpentine minerals, which are produced by interaction between ultramafic rocks and fluids, contain about 13% water and are the greatest carrier of H2O into the deep interior of Earth. Therefore, the volume and distribution of hydrated oceanic mantle are of special interest in evaluating the effects of fluids on subduction zone processes. We conducted hydrothermal experiments in olivine (Ol; Fo91)-H2O and orthopyroxenite (Opx; composed of 95% of orthopyroxene, En66)-H2O systems under conditions of 250 C and vapor-saturated pressure (Psat) to examine the temporal evolution of the solution chemistry and products in runs of up to 1008 h in duration. The maximal degree of hydration (i.e., H2O content in the solid sample) in the Ol-H2O experiments (3.6 wt.%) was much higher than that in the Opx-H2O experiments (0.4 wt.%). In the Ol-H2O experiments, Mg and Si in solution showed an initial increase (stage 1) before decreasing (stage 2) and finally attaining a steady state after 504 h (stage 3). Following a drop in silica activity toward the level of brucite stability filed, the products also changed from serpentine + magnetite (stages 1 and 2) to serpentine + brucite + magnetite (stage 3). Serpentine minerals also changed from lizardite (stages 1 and 2) to lizardite + chrysotile (stage 3). The textures observed in this study were similar to those observed in partly serpentinized dunites. In the Opx-H2O experiments, chlorite formed after orthopyroxene grains, which differs from the formation of talc and serpentine after orthopyroxene (bastite), as observed in natural hydrated harzburgites. The Opx-H2O system maintained 10-103 times higher silica activity than Ol-H2O system, suggesting that brucite does not form after olivine during hydration of peridotites when the Ol-H2O system is linked to the Opx-H2O system. The progress of hydration reactions is affected by mechanical properties of host rocks. The hydration reactions observed in this study produced hierarchical fractures in the reactants, which became filled with reaction products, similar to mesh textures after olivine in natural peridotites. This reaction-induced fracturing produced new reaction surfaces and fluid pathways that enhanced the hydration reactions. The overall reaction producing serpentine+brucite in the Ol-H2O experiments showed the large volume expansion (V/V0 = 1.38 at stage 3), whereas that producing only serpentine proceeded with near constant volume (V/V0 = 1.09 at stage 1). The volume expansion is more difficult to occur in the oceanic lithosphere than in our experiments during serpentinization. Thus, in the case that volume expansion is prevented at reaction sites, one of the following outcomes occurs: (1) the hydration reaction stops until new fractures form, or (2) the reaction proceeds with low volume expansion (absence of brucite) by removing Mg from the system. These two outcomes would produce contrasting distributions or extent of hydration in oceanic lithosphere.

Okamoto, A.; Ogasawara, Y.; Tsuchiya, N.

2011-12-01

13

Heat capacity, saturation vapor pressure, and thermodynamic functions of ethyl esters of C3-C5 and C18 carboxylic acids  

NASA Astrophysics Data System (ADS)

The heat capacities of ethyl propanoate (EPr), ethyl n-pentanoate (EPen), and ethyl n-octadecanoate (ethyl stearate, ESt) were measured by vacuum adiabatic calorimetry in the temperature range of 6 to 373 K. Triple point temperatures, fusion enthalpies and entropies, and purity of the samples of the sub-stances under study were determined. The saturation vapor pressures for EPr and EPen were determined by comparative ebulliometry in an atmospheric pressure range of 4.0 to 101.7 kPa. The normal boiling points and vaporization enthalpies vs. temperature were obtained. The standard thermodynamic functions ( S, H, and G) were calculated for the condensed and ideal gas states on the basis of the experimental data. The vapor pressures of the atmospheric range were extrapolated to entire ranges of the liquid phases of EPr and EPen using the principle of corresponding states and the combined processing of pT parameters and low-temperature differences in the heat capacities of an ideal gas and liquid.

Agafonova, L. E.; Varushchenko, R. M.; Druzhinina, A. I.; Polyakova, O. V.; Kolesov, Yu. S.

2011-09-01

14

Sedimentair equilibrium partitioning of semi-volatile hydrophobic organic compounds Part 2. Saturated vapor pressures, and the effects of sediment moisture content and temperature on the partitioning of polyaromatic hydrocarbons  

Microsoft Academic Search

A gas saturation methodology was used to determine the sediment\\/air partition coefficient (KSA) for phenanthrene and dibenzofuran on a local sediment from the Campus Lake, Baton Rouge. The effects of sediment moisture content, air relative humidity and temperature on KSA for phenanthrene were ascertained. The saturated vapor pressures of the compounds were also measured. The sediment moisture content had a

G de Seze; K. T Valsaraj; D. D Reible; L. J Thibodeaux

2000-01-01

15

Lubricant Vapor Pressure Derived from Evaporation Loss  

Microsoft Academic Search

A method is presented for obtaining vapor pressures over the temperature range of interest in engine lubrication (300500 F). The determination is based on the saturation efficiency of an air stream and the relationship between vapor pressure and evaporation loss. All data required are readily obtained from the ASTM Evaporation Test Method D 972-56 which is already used in connection

John F. Coburn

1969-01-01

16

Vapor Pressure and Solvent Vapor Hazards  

Microsoft Academic Search

This paper discusses applications of vapor pressure to industrial hygiene. Vapor pressure is the quantitative term characterizing solvent volatility; it is also equivalent to the concentration of solvent vapor at the liquid surface. The ratio between this concentration at the source and the acceptable concentration at the breathing zone is an intrinsic property of each chemical but varies over 6

WILLIAM POPENDORF

1984-01-01

17

Thermal conductivity of R32 and R125 in the liquid phase at the saturation vapor pressure  

Microsoft Academic Search

The first measurements of the thermal conductivity of two refrigerants which are candidates for the replacement of those fluids currently in use are reported. Specifically, results are given for the thermal conductivity of R32 and R125 in the liquid phase along the saturation line. The measurements, which have been made by the transient hot-wire technique, extend over the temperature range

M. Papadaki; W. A. Wakeham

1993-01-01

18

Thermal conductivity of R32 and R125 in the liquid phase at the saturation vapor pressure  

Microsoft Academic Search

The first measurements of the thermal conductivity of two refrigerants which are candidates for the replacement of those fluids\\u000a currently in use are reported. Specifically, results are given for the thermal conductivity of R32 and R125 in the liquid\\u000a phase along the saturation line. The measurements, which have been made by the transient hot-wire technique, extend over the\\u000a temperature range

M. Papadaki; W. A. Wakeham

1993-01-01

19

Thermal conductivity of R32 and R125 in the liquid phase at the saturation vapor pressure  

NASA Astrophysics Data System (ADS)

The first measurements of the thermal conductivity of two refrigerants which are candidates for the replacement of those fluids currently in use are reported. Specifically, results are given for the thermal conductivity of R32 and R125 in the liquid phase along the saturation line. The measurements, which have been made by the transient hot-wire technique, extend over the temperature range from 205 to 303 K for R32 and from 225 to 306 K for R125; the results have an estimated uncertainty of 1.0%.

Papadaki, M.; Wakeham, W. A.

1993-11-01

20

Experimental study of copper(I) chloride complexing in hydrothermal solutions at 40 to 300C and saturated water vapor pressure  

Microsoft Academic Search

The solubility of Cu phases was measured in vapor-saturated aqueous HCl\\/NaCl solutions at temperatures ranging from 40 to 300C, total chloride concentration from 0.01 to 1 m, and pH from 0 to 3.5. For temperatures up to and including 150C, CuCl(s) was used as the solid reactant. At higher temperatures, foils of metallic Cu and Ag were used. Silver was

Zhifeng Xiao; C. H. Gammons; A. E. Williams-Jones

1998-01-01

21

An experimental study of copper(I)-chloride and copper(I)-acetate complexing in hydrothermal solutions between 50C and 250C and vapor-saturated pressure  

NASA Astrophysics Data System (ADS)

The transport of copper is affected by complexing with ligands such as chloride, bisulphide and acetate. Many copper deposits are formed from hydrothermal waters and brines and in order to understand their formation we need thermodynamic properties of aqueous copper species. The solubility of cuprite experiments in pH-buffered acetate and chloride solutions was determined at 50C, 150C and 250C and water vapor saturated pressures. Chloride and acetate concentrations were varied using NaCl (0.001m to 2 m) and NaAc (0.1m to 2 m, where Ac refers to acetate). Measured copper concentrations varied between 0.0001 m and 0.2 m and show systematic increases with increasing temperature and acetate or chloride concentration. Logarithms of the formation constants (log K) of copper complexes were fitted by a simplex function minimization method, then speciation models and uncertainties of fitted log K values were examined by residual maps and speciation plots of experimental solutions. Interpretation of our experimental data shows that CuCl (aq), CuCl 2-, CuAc (aq) and CuAc 2- were present in our experiments at all temperatures. CuCl 32- is an important complex at 50C, but cannot be detected unequivocally at 150C and 250C. This study presents the first experimentally-derived log K values for copper(I) acetate complexes (CuAc (aq) and CuAc 2-). The derived log K values of copper(I) chloride complexes (CuCl (aq) and CuCl 2-) are similar to recently published experimentally derived values (Xiao et al., 1998). Based on new log K values generated from this study, our calculations indicate that copper transport as acetate complexes is important in acetate-bearing fluids lacking competition of other ligands such as Cl - and HS -.

Liu, Weihua; McPhail, D. C.; Brugger, Jol

2001-09-01

22

Vapor pressure, heat capacity, and density along the saturation line, measurements for dimethyl isophthalate, dimethyl carbonate, 1,3,5-triethylbenzene, pentafluorophenol, 4-tert-butylcatechol, {alpha}-methylstyrene, and N,N{prime}-bis(2-hydroxyethyl)ethylenediamine  

SciTech Connect

Vapor pressures were measured to a pressure limit of 270 kPa or lower decomposition point for all seven compounds using a twin ebulliometric system and, for dimethyl isophthalate and N,N{prime}-bis(2-hydroxyethyl)-ethylenediamine, additionally an inclined-piston apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperature (ambient to a maximum of 548 K). A differential scanning calorimeter (DSC) was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. Where possible, the critical temperature and critical density for each compound were determined experimentally. The results of the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies of vaporization (restricted to within {+-}50 K of the temperature region of the experimentally determined vapor pressures), enthalpies of fusion if solid at ambient temperature, solubility parameter, and heat capacities along the saturation line. Wagner-type vapor-pressure equations were derived for each compound. In addition, the liquid-phase densities were compared with values derived using a three-term [(1 {minus} T{sub r}){sup 1/3}] power series. All measured and derived values were compared with those obtained in a search of the literature. Recommended critical parameters are listed for each of the compounds studied. A Rule-Of-Thumb derived in the 1992 Project Year is used to estimate thermal decomposition temperatures by radical scission from a knowledge of the bond dissociation energy or vice versa.

Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A. [National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States)

1997-11-01

23

The Vapor Pressure of Barium.  

National Technical Information Service (NTIS)

The vapor pressure and the heat of vaporization of barium were measured using the Knudsen target technique. A recording microbalance was used to measure both the effusion rate and the recoil force exerted by the beam onto the target. The measured vapor pr...

P. D. Zavitsanos

1968-01-01

24

Specific heats of saturated water vapor and liquid  

NASA Astrophysics Data System (ADS)

This paper introduces a modification of the expression for the specific heat of saturated vapor attributed to Clausius and widely used in the literature. The proposed formula contains an additional term which avoids the often-criticized negative value of the specific heat of saturated vapor. Results are given for the case of water.

Elsner, Albrecht

1993-09-01

25

Determination of Evaporation Rate and Vapor Pressure of Organic Monomers Used for Vapor Deposition Polymerization  

Microsoft Academic Search

Thermogravimetry (TG) and the Langmuir equation have been employed for the determination of the temperature dependence of the evaporation rate and saturated pressure of monomers used in vapor deposition polymerization (VDP). The measuring process utilizes the evaporation of monomers in vacuum. The ranges of the evaporation rate and saturated pressure of monomers as determined by the TG technique are from

Yoshikazu Takahashi; Kanenori Matsuzaki; Masayuki Iijima; Eiichi Fukada; Sonoko Tsukahara; Yukimasa Murakami; Akikazu Maesono

1993-01-01

26

CC Cryostat Vapor Pressure Thermometers  

SciTech Connect

Vapor pressure thermometers will be used to measure the temperature or the liquid argon in the cryostat at two different levels. One bulb will be positioned near the top of the vessel, and a second bulb will be located near the bottom of the vessel. The volume of the bulbs is dependent upon the charge temperature and pressure chosen, the temperature range of the thermometer desired, the size and length of tubing used, and the warm volume involved.

Kurita, C.H.; /Fermilab

1987-10-01

27

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus  

ERIC Educational Resources Information Center

|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

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

2007-01-01

28

Sediment-air equilibrium partitioning of semi-volatile hydrophobic organic compounds part 2. Saturated vapor pressures, and the effects of sediment moisture content and temperature on the partitioning of polyaromatic hydrocarbons.  

PubMed

A gas saturation methodology was used to determine the sediment/air partition coefficient (K(SA)) for phenanthrene and dibenzofuran on a local sediment from the Campus Lake, Baton Rouge. The effects of sediment moisture content, air relative humidity and temperature on K(SA) for phenanthrene were ascertained. The saturated vapor pressures of the compounds were also measured. The sediment moisture content had a striking effect on K(SA); increasing sediment moisture content decreased K(SA). Temperature also had a dramatic effect on K(SA). The variation with temperature was used to evaluate the heats of adsorption on both 'dry' (< 0.8% by mass of water) and 'wet' (> 6% by mass of water) sediments. The heat of adsorption for phenanthrene normalized to unit molecular surface area indicated for the physically adsorbed organic compound was seven times smaller than that for a water molecule. The experimental value of K(SA) was used to test a proposed theoretical model. A good agreement was observed for both phenanthrene and dibenzofuran. The model can be extended to other compounds and sediment types for prediction of air emissions from exposed sediment and dredged materials. PMID:10843329

de Seze, G; Valsaraj, K T; Reible, D D; Thibodeaux, L J

2000-05-15

29

Capillary PressureSaturation Relations for Saprolite  

Microsoft Academic Search

Dense nonaqueous phase liquids (DNAPLs) are important subsurface contaminants. Information is lacking on DNAPL behavior in heterogeneous porous media such as weathered rock (saprolite). We measured airwater and Fluorinert (a nontoxic DNAPL surrogate; 3M, St. Paul, MN)water capillary pressuresaturation relations, ?w(hc), close to saturation on an 18-cm-long by 10-cm-diameter undisturbed column of interbedded sandstone and clayshale saprolite. The Campbell empirical

E. Perfect; Larry McKay; S. C. Cropper; S. G. Driese; G. Kammerer; J. H. Dane

2004-01-01

30

Vapor Pressure of Methylphosphonic Dichloride: A Compendium.  

National Technical Information Service (NTIS)

Vapor-pressure data for methylphosphonic dichloride from many sources are reviewed and analyzed to obtain a best-fit predictive Antoine equation. Also given are the heat of vaporization and volatility at various temperatures. Zeffert published an Antoine ...

A. Brozena D. Fielder

1985-01-01

31

Interfacial instability induced by lateral vapor pressure fluctuation in bounded thin liquid-vapor layers  

NASA Astrophysics Data System (ADS)

We study an instability of thin liquid-vapor layers bounded by rigid parallel walls from both below and above. In this system, the interfacial instability is induced by lateral vapor pressure fluctuation, which is in turn attributed to the effect of phase change: evaporation occurs at a hotter portion of the interface and condensation at a colder one. The high vapor pressure pushes the interface downward and the low one pulls it upward. A set of equations describing the temporal evolution of the interface of the liquid-vapor layers is derived by applying long-wave approximation to both layers. This model neglects the effect of mass loss or gain at the interface and guarantees the mass conservation of the liquid layer. The result of linear stability analysis of the model shows that the presence of the pressure dependence of the local saturation temperature mitigates the growth of long-wave disturbances. The thinner vapor layer enhances the vapor pressure effect. We find the stability criterion, which suggests that only slight temperature gradients are sufficient to overcome the gravitational effect for a water/vapor system. The same holds for the Rayleigh-Taylor unstable case, with a possibility that the vapor pressure effect may be weakened if the accommodation coefficient is below a certain critical value.

Kanatani, Kentaro

2010-01-01

32

Saturated Vapour Pressure and Refrigeration - Part I  

ERIC Educational Resources Information Center

|The first part of a two-part article describes an experimental approach that can be used in teaching the concept of saturated vapour pressure. This leads to a discussion of refrigeration cycles in the second part of the article. (JR)|

Bunker, C. A.

1973-01-01

33

Predicting vapor pressures using neural networks  

Microsoft Academic Search

Calculating surface vapor pressures of volatile inorganic components, nitric acid, hydrochloric acid and ammonia, is essential for modeling condensation and evaporation processes occurring in atmospheric aerosols. The vapor pressure of these compounds depends on temperature, relative humidity, phase state, and particle composition, and their calculation consumes an enormous amount of computer time in Eulerian photochemical\\/aerosol models. Here we use a

Sudhakar Potukuchi; Anthony S. Wexler

1997-01-01

34

Absence of a vestigial vapor pressure paradox  

Microsoft Academic Search

The enigmatic but much accepted vapor pressure paradox for oriented lipid bilayer samples was recently justified theoretically. Subsequently, recent experiments have shown that there is no vapor pressure paradox. The first result of this paper is to consider another degree of freedom that reverses the previous theoretical conclusion, so that theory and experiment are now in agreement that there is

John F. Nagle; John Katsaras

1999-01-01

35

VAPOR PRESSURE OF POLYPHENYL COOLANT AND COMPONENTS  

Microsoft Academic Search

Studies were undertaken to measure the vapor pressure of organic coolant ; materials over the temperature range 450 to 900 deg F. The vapor pressure of ; diphenyl, Santowax R and ortho-, meta-, and para-terphenyl was determined ; experimentally. (W.L.H.)

Silvey

1959-01-01

36

Absence of a vestigial vapor pressure paradox  

NASA Astrophysics Data System (ADS)

The enigmatic but much accepted vapor pressure paradox for oriented lipid bilayer samples was recently justified theoretically. Subsequently, recent experiments have shown that there is no vapor pressure paradox. The first result of this paper is to consider another degree of freedom that reverses the previous theoretical conclusion, so that theory and experiment are now in agreement that there is no vapor pressure paradox. However, this analysis also suggests the possibility of a vestigial vapor pressure paradox that would rationalize why the vapor pressure paradox was historically so persistent and that would have led to an improved protocol for obtaining bilayer structure. This vestigial vapor pressure paradox would involve a phase transition as a function of applied osmotic pressure. We test this possibility experimentally using combined neutron and x-ray scattering data. The conclusion from these experiments is that there is not even a vestigial vapor pressure paradox. However, this negative result validates an improved method for calibrating osmotic pressure in x-ray studies of oriented samples.

Nagle, John F.; Katsaras, John

1999-06-01

37

Multicomponent fuel vaporization at high pressures.  

SciTech Connect

We extend our multicomponent fuel model to high pressures using a Peng-Robinson equation of state, and implement the model into KIVA-3V. Phase equilibrium is achieved by equating liquid and vapor fugacities. The latent heat of vaporization and fuel enthalpies are also corrected for at high pressures. Numerical simulations of multicomponent evaporation are performed for single droplets for a diesel fuel surrogate at different pressures.

Torres, D. J. (David J.); O'Rourke, P. J. (Peter J.)

2002-01-01

38

Assessment of the Accuracy and Computing Speed of Simplified Saturation Vapor Equations Using a New Reference Dataset.  

NASA Astrophysics Data System (ADS)

A revised saturation vapor dataset is proposed for use in meteorology. Based on new engineering data of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers for temperatures above 0C, it should supersede the older Smithsonian and World Meteorological Organization meteorological tables.Simple new equations are proposed to compute the saturation vapor pressure over water between 50 and 50C. Their accuracy is shown to be excellent over this range, with an nns error of 3 103 mb and an average relative error of 0.02%. Detailed statistics descrbing the accuracy performance of 22 other equations are presented and the speed performance of all these equations is assessed. Nested polynomials are shown to provide both good accuracy and computational speed. On a modern minicomputer, a single evaluation of saturation vapor pressure may take less than 1 s of CPU time, 15 times less than required by the Goff Gratch equations that were used to construct the meteorological tables.

Gueymard, Christian

1993-07-01

39

40 CFR 796.1950 - Vapor pressure.  

Code of Federal Regulations, 2013 CFR

...addition, chemicals that are likely to be gases at ambient temperatures and which...likely to transport and persist in soils and water. Such chemicals are less...by removing dissolved and entrained gases until the measured vapor pressure...

2013-07-01

40

Vapor Pressure of Diffusion Pump Oils.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A thermogravimetric procedure has been developed for the determination of the vapor pressure of diffusion pump oils by using a Knudsen effusion cell in conjunction w...

1981-01-01

41

VAPOR PRESSURE DISTRIBUTION OF SELECTED ORGANIC CHEMICALS  

EPA Science Inventory

A tabulation of vapor pressures for organic chemical products currently considered for inclusion in fugitive emissions regulations was prepared. For each of the 378 chemicals (or groups of chemicals) identified by the Emission Standards and Engineering Division, the following dat...

42

Vapor-Pressure Measurements by Effusion Methods.  

National Technical Information Service (NTIS)

Vapor pressure measurements were made on FeCl2, FeBr2, FeI2, Sb, Bi, Cd, Mg, Pb, FeCl3, and VCl2 using the Knudsen and torsion effusion methods and on FeCl3-NaCl mixtures, Au2Cl6 and MgNi2 using only the Knudsen method. Apparent vapor pressures calculated...

A. Landsberg A. Adams S. D. Hill

1977-01-01

43

Laminar boundary layer flow of saturated vapor and its condensate over a horizontal tube  

NASA Astrophysics Data System (ADS)

The steady two-dimensional laminar flow of a stream of saturated vapor flowing over a tube that is kept at a uniform temperature, below the saturation temperature, is examined. Owing to the temperature difference between the vapor stream and the solid surface a film of condensate is generated that flows along the surface due to shear, pressure-drop, and gravity. In the limit as the boundary layer and film thickness remain smaller than the radius of curvature of the surface a simplified lubrication-type formulation describes the temperature and flow fields in the film, whereas the usual boundary layer formulation is applied in the vapor boundary layer. The case of flow past a horizontal cylinder of radius R is investigated numerically with the oncoming stream aligned with gravity. The parameters that control momentum and heat transfer in this problem are the viscosity ratio, ?cs/?ss, the density ratio, ?cs/?ss, the Prandtl number, Pr=cpcs?cs/kcs, the Froude number, Fr=U?2/(g?R), and finally the thickness ratio between the condensate and the vapor boundary layer, ?, which is also a measure of the temperature difference between the vapor stream and the tube wall. Then, the Nusselt number and the skin friction coefficient, averaged over the upper half of the cylinder, are calculated for a wide parameter range. When Fr is very small and V relatively large the flow remains attached until the trailing stagnation point of the cylinder. As the effect of adverse pressure drop becomes more pronounced (Fr increases or V decreases) it is shown that the solution exhibits two different types of singularity in the rear part of the cylinder. The first one is a typical Goldstein singularity because it appears at the tube wall and it is associated with vanishing skin friction (wall shear) and rapidly increasing film thickness. The second one takes place near the interface between the vapor stream and the film of condensate in a region where very small velocities prevail in conjunction with vanishing shear rate. The latter has not been reported so far and it is expected to affect the flow locally, as opposed to the Goldstein singularity which is known to lead to massive separation in the case of a cylindrical surface. Upon proper rescaling of Fr and V, Fr'=Fr ?ss/?cs, V'=V6(?ss/?cs)7/2(?cs/?ss)7/2, a critical curve is produced in the (Fr',V') plane that marks the boundary curve separating the two types of singular behavior for most of the numerical data obtained herein for the steam-water system, irrespective of the saturation temperature.

Smyrnaios, D. N.; Pelekasis, N. A.; Tsamopoulos, J. A.

2002-06-01

44

Clausius-Clapeyron Equation and Saturation Vapour Pressure: Simple Theory Reconciled with Practice  

ERIC Educational Resources Information Center

|While the Clausius-Clapeyron equation is very important as it determines the saturation vapour pressure, in practice it is replaced by empirical, typically Magnus-type, equations which are more accurate. It is shown that the reduced accuracy reflects an inconsistent assumption that the latent heat of vaporization is constant. Not only is this

Koutsoyiannis, Demetris

2012-01-01

45

Vapor Pressure, Speed of Sound, and PVT Properties of R-404a in the Vapor Phase  

Microsoft Academic Search

The density (300363K, up to 3.5MPa) and speed of sound (293373K, 7.5480kPa) in gaseous R-404a have been studied by\\u000a an isochoric piezometer method and an ultrasonic interferometer, respectively. The pressures of the saturated vapor along\\u000a the dew line were measured from 298 to 330K. The experimental uncertainties of the temperature, pressure, density, and speed-of-sound\\u000a measurements were estimated to be within

V. A. Gruzdev; S. G. Komarov; S. V. Stankus

2008-01-01

46

46 CFR 154.451 - Design vapor pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure. 154.451 Section...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent...Process Pressure Vessels § 154.451 Design vapor pressure. The Po...

2011-10-01

47

Vapor pressures of the aqueous desiccants  

SciTech Connect

The vapor pressures of the aqueous desiccants lithium chloride, lithium bromide, calcium chloride, ethylene glycol, propylene glycol, and their mixtures were measured at their typical operating concentrations and at temperatures from 298 K to 313 K. The experimental data were fitted to an Antoine type of equation, ln[P(kPa)] = A {minus} B/[T(K) + C], where A, B, and C are constants and are concentration dependent. Vapor pressure data were further used to predict the effectiveness of dehumidification in liquid desiccant dehumidifiers.

Chung, T.W.; Luo, C.M. [Chung Yuan Christian Univ., Chungli (Taiwan, Province of China). Chemical Engineering Dept.

1999-09-01

48

Toward Carbon Dioxide Vapor-Pressure Thermometer  

NASA Astrophysics Data System (ADS)

The Temperature Group Laboratory of the National Metrology Institute of Turkey (TUBITAK UME) has realized the scale in the range from the argon triple point (83.8058 K) to the copper freezing point (1357.77 K) and also constructed the International Temperature Scale of 1990 (ITS-90) defining fixed points (Preston-Thomas, Metrologia 27, 3 (1990)). The scale is realized in the low-temperature sub-range by interpolation between the triple points of water, mercury, and argon. The calibration of thermometers below the temperature of the triple point of mercury requires the realization of the argon triple point. Since calibration laboratories are asking for references down to -60 C, a triple point of carbon dioxide (CO2) gives this opportunity to be used as a secondary fixed point. Another aim of this work is to study the ability of CO2 vapor pressure to realize a vapor-pressure thermometer for covering the range from 216 K up to room temperature. This realization is intended to provide an approximation of the international temperature scale in this temperature range. The vapor-pressure thermometer is intended to be assessed by using the triple point of carbon dioxide and by measuring the pressure values at the temperatures of the triple points of mercury and water. Realization of the triple-point temperature of carbon dioxide and the development of the vapor-pressure thermometer will be investigated and presented in this article.

Dogan, A. Kartal; Bonnier, G.; Uytun, A.; Kocas, I.; Durgut, Y.

2011-12-01

49

Vapor Pressure of Fluids in High-Pressure Gas Atmospheres.  

National Technical Information Service (NTIS)

As part of the investigation of the critical parameters in the combustion of hydraulic fluids, experiments were conducted to verify the accuracy of the Poynting equation which predicts the effect of inert gas pressure upon the vapor pressure of a liquid. ...

D. R. Ventriglio R. W. McQuaid

1967-01-01

50

MISTING OF LOW VAPOR PRESSURE HALOCARBONS  

EPA Science Inventory

The paper gives results of a laboratory-scale study of the use of misting systems to provide total-flood fire protection with lower vapor pressure halocarbons. (NOTE: Several candidate Halon 1301 replacements with a low ozone-depletion potential have higher boiling points (usuall...

51

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, April 1--June 30, 1995  

SciTech Connect

The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. Both the gas saturation method and the Knudsen effusion method are being used. Results are presented for anthracene, naphthacene, pentacene, and a mixture of anthracene and perylene obtained using the effusion method.

Suuberg, E.M.

1995-10-01

52

Low light level saturated absorption in tapered fiber embedded in alkali vapor  

Microsoft Academic Search

We demonstrate ultra-low light level saturated absorption in a tapered fiber embedded in an atomic vapor. This shows the potential for extremely low light level optical switching and quantum information processing with such a device.

G. S. Pati; S. Spillane; R. Beausoleil; K. Salit; M. Hall; P. Kumar; M. S. Shahriar

2007-01-01

53

Vapor Pressure, Speed of Sound, and PVT-Properties of R-404a in the Vapor Phase  

Microsoft Academic Search

The density (300 363 K, up to 3.5 MPa) and speed of sound (293 373 K, 7.5 480 kPa) in gaseous R-404a have been studied by an isochoric piezometer method and an ultrasonic interferometer, respectively. The pressures of the saturated vapor along the dew line were measured from 298 to 330 K. The experimental uncertainties of the temperature, pressure, density,

V. A. Gruzdev; S. G. Komarov; S. V. Stankus

2008-01-01

54

A practical vapor pressure equation for helium-3 from 0.01 K to the critical point  

Microsoft Academic Search

A saturation vapor pressure equation, p(T), is an essential component in the 3He state equation currently under development. The state equation is valid over the range 0.0120K with pressures from 0 to the melting pressure or 15MPa. The vapor pressure equation consequently must be valid from 0.01K to the critical temperature. This paper surveys available 3He critical temperature and pressure

Y. H. Huang; G. B. Chen

2006-01-01

55

46 CFR 154.436 - Design vapor pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure. 154.436 Section...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Semi-Membrane Tanks § 154.436 Design vapor pressure. The Po of...

2011-10-01

56

46 CFR 154.438 - Design vapor pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure. 154.438 Section...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.438 Design vapor pressure. (a) If the...

2011-10-01

57

46 CFR 154.445 - Design vapor pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure. 154.445 Section...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type B § 154.445 Design vapor pressure. If the...

2011-10-01

58

46 CFR 154.426 - Design vapor pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure. 154.426 Section...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Membrane Tanks § 154.426 Design vapor pressure. The Po of a...

2011-10-01

59

46 CFR 154.419 - Design vapor pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure. 154.419 Section...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.419 Design vapor pressure. The Po of...

2011-10-01

60

Heating of a fully saturated darcian half-space: Pressure generation, fluid expulsion, and phase change  

USGS Publications Warehouse

Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space. ?? 1984.

Delaney, P.

1984-01-01

61

On the propagation of a coupled saturation and pressure front  

SciTech Connect

Using an asymptotic technique, valid for a medium with smoothly varying heterogeneity, I derive an expression for the velocity of a propagating, coupled saturation and pressure front. Due to the nonlinearity of the governing equations, the velocity of the propagating front depends upon the magnitude of the saturation and pressure changes across the front in addition to the properties of the medium. Thus, the expression must be evaluated in conjunction with numerical reservoir simulation. The propagation of the two-phase front is governed by the background saturation distribution, the saturation-dependent component of the fluid mobility, the porosity, the permeability, the capillary pressure function, the medium compressibility, and the ratio of the slopes of the relative permeability curves. Numerical simulation of water injection into a porous layer saturated with a nonaqueous phase liquid indicates that two modes of propagation are important. The fastest mode of propagation is a pressure-dominated disturbance that travels through the saturated layer. This is followed, much later, by a coupled mode with a large saturation change. These two modes are also observed in a simulation using a heterogeneous porous layer. A comparison between the propagation times estimated from the results of the numerical simulation and predictions from the asymptotic expression indicates overall agreement.

Vasco, D. W.

2010-12-01

62

Solubility of hydrogen sulfide in pure water and in NaCl solutions, from 20 to 320C and at saturation pressures  

Microsoft Academic Search

The solubility of hydrogen sulfide in pure water and in NaCl solutions has been studied experimentally from 20 to 320C and at saturation pressures. Hydrogen sulfide solutions in equilibrium with their vapor phase were contained in a pressurized titanium bellows of known total volume. The bellows transmitted inside-vapor pressures via a thermally stable oil (pressure medium) to a high-precision pressure

O. M. Suleimenov; R. E. Krupp

1994-01-01

63

The Vapor Pressure of HCl - Water Solutions Below 0C.  

National Technical Information Service (NTIS)

An experimental study has been initiated to measure the equilibrium vapor pressure of solutions of hydrochloric acid at temperatures from 0 to -55C. Total vapor pressure data and calculated heat of vaporization values are reported for 19.9 wt pct and 36.0...

E. Miller

1978-01-01

64

Notes on Vapor Pressure Equilibria Measurements  

NASA Astrophysics Data System (ADS)

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.

Krieger, Albert G.; Henderson, John W.

1996-11-01

65

In situ direct measurement of vapor pressures and thermodynamic parameters of volatile organic materials in the vapor phase: benzoic acid, ferrocene, and naphthalene.  

PubMed

We report the direct determination of vapor pressures and optical and thermodynamic parameters of powders of low-volatile materials in their vapor phase using a commercial UV/Vis spectrometer. This methodology is based on the linear proportionality between the density of the saturated gas of the material and the absorbance of the gas at different temperatures. The vapor pressure values determined for benzoic acid and ferrocene are in good agreement with those reported in the literature with ?2-7?% uncertainty. Thermodynamic parameters of benzoic acid, ferrocene, and naphthalene are determined in situ at temperatures below their melting points. The sublimation enthalpies of the investigated organic molecules are in excellent agreement with the ICTAC recommended values (less than 1?% difference). This method has been used to measure vapor pressures and thermodynamic parameters of organic volatile materials with vapor pressures of ?0.5-355 Pa in the 50-100?C temperature range. PMID:23606455

Hikal, Walid M; Weeks, Brandon L

2013-04-19

66

Wetting of coal dust by gas saturated with water vapor. [4 refs  

Microsoft Academic Search

Control of suspended coal dust is made less effective because coal is hydrophobic, so that a water droplet does not coalesce with a dust particle every time they collide or touch. Thus the efficiency of dust suppression by irrigation at the face can be improved by creating saturated water vapor in the air near the cutting head of the cutter-loader.

M. I. Feskov; A. N. Kurdyukov

1976-01-01

67

A theoretical model of laser ionization of alkali vapors based on resonance saturation  

Microsoft Academic Search

We have developed a theoretical model of the ionization that results from extended laser saturation of an atomic resonance transition within a dense alkali vapor. Although this model includes all of the essential collisional-radiative interactions, nevertheless, it leads to relatively simple analytical relations that predict the ionization time history to within 20% of that calculated by our extensive laser ionization

P. G. Cardinal; G. W. Schinn

1981-01-01

68

A theoretical model of laser ionization of alkali vapors based on resonance saturation  

Microsoft Academic Search

A theoretical model of the ionization that results from extended laser saturation of an atomic resonance transition within a dense alkali vapor has been developed. Although this model includes all of the essential collisional-radiative interactions, nevertheless it leads to relatively simple analytical relations that predict the ionization time history to within 20% of that calculated by an extensive laser ionization

P. G. Cardinal; G. W. Schinn

1981-01-01

69

Vapor-liquid equilibrium for carbon dioxide + 1-butanol at high pressure  

Microsoft Academic Search

Phase equilibrium properties of mixtures at high pressures are required for practical use such as in the design and operation of separation equipment in the petroleum natural gas, and related industries. Vapor-liquid equilibria and saturated densities for carbon dioxide + 1-butanol at high pressures were measured at 313.15 K including in the vicinity of the critical region with the static-circulation

Katsuo Ishihara; Akira Tsukajima; Hiroyuki Tanaka; Masahiro Kato; Takeshi Sako; Masahito Sato; Toshikatsu Hakuta

1996-01-01

70

Vaporization and Boiling of a Material at High Pressure (Generalization of Clausius-Clapeyron Equation)  

NASA Astrophysics Data System (ADS)

To determine the vapor-phase concentration on the surface of the particle or drop, the well-known Clausius-Clapeyron equation is applied. In the case of the detonation of a mixture with metallic particles, where the pressure in the reaction zone is of the order of 1.0E+10 Pa, the Clausius-Clapeyron equation determining the partial pressure of a saturated vapor in a vacuum may be incorrect. The study is carried out within the framework of equilibrium thermodynamics, and the correlation obtained is a generalization of the Clausius-Clapeyron equation for the case when the external pressure is not zero. It is assumed that the vapor and the liquid (or solid) phases of the material are in equilibrium, whereas the liquid phase is under a pressure equal to the sum of the vapor presure and the external pressure. A new equation for the partial vapor pressure is used for determining the boiling point versus external pressure. It is shown that with high pressures, the values for the boiling point are significantly lower compared with data published for metals and oxides.

Gonor, Alexander

2001-06-01

71

Preliminary assessment of condensation behavior for hydrocarbon-vapor expansions which cross the saturation line near the critical point  

SciTech Connect

Previous analyses of binary cycles for conversion of geothermal energy from moderate temperature resources to electrical energy have shown potential gains in net geofluid effectiveness of on the order of 8%, resulting from selection of turbine-expansion processes whose equilibrium states pass through the two-phase region (assuming major condensation does not occur). If condensation occurs, this gain could be reduced or eliminated by the resulting loss in turbine efficiency. Experience with many fluids, however, indicates that vapor supersaturation (or subcooling) permits metastable pure-vapor states to exist at temperatures considerably below the saturation temperature at a given pressure; thus, by better understanding the condensation process, and properly structuring the cycle, substantial performance gains may be achievable. The present study assessed, qualitatively, the probability for attaining this performance gain.

Demuth, O.J.

1982-07-01

72

Temperature dependent vapor pressures of chlorinated catechols, syringols, and syringaldehydes  

Microsoft Academic Search

The vapor pressures of nine chlorinated catechols, syringols, and syringaldehydes were determined as a function of temperature with a gas chromatographic retention time technique. The vapor pressures at 298.15 K were in the range of 0.02--1 Pa, and the enthalpies of vaporization, between 68 and 82 kJ\\/mol. The validity of the technique was established by a calibration involving four chlorinated

Ying Duan Lei; W. Y. Shiu; D. G. B. Boocock; F. Wania

1999-01-01

73

46 CFR 154.438 - Design vapor pressure.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Design vapor pressure. 154.438 Section 154.438 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...Construction and Equipment Independent Tank Type A § 154.438 Design vapor pressure. (a) If the surface...

2012-10-01

74

Raising vapor pressure of gasoline by methanol and ethanol  

Microsoft Academic Search

Mixtures including alcohols were observed to have higher vapor pressures than would be calculated on the basis of usual calculations involving percent composition of the mixture and vapor pressure of individual components as measured in the pure state. This discrepancy was explained by noting that pure alcohol was in an associated state whereas that association was broken up in mixtures.

Grimme

1938-01-01

75

Vapor pressure of tri-n-butyl phosphate  

SciTech Connect

The vapor pressure of tri-n-butyl phosphate (TBP) and dibutylphenyl phosphate (DBPP) have been determined from gas chromatographic retention times and from measurement of the equilibrium vapor concentrations. Also, the partial pressures of these compounds in the headspace of a hydraulic fluid were measured. The obtained values have been compared with published data.

Skene, W.G.; Krzymien, M.E. [National Research Council, Ottawa, Ontario (Canada). Inst. for Environmental Research and Technology

1995-03-01

76

LATENT HEAT OF VAPORIZATION AND VAPOR PRESSURE DATA FOR ORGANIC COOLANTS  

Microsoft Academic Search

In order to estimate the performance of flash distillation equipment for ; the purification of organic coolants, heat of vaporization and vapor pressure ; data for the coolant components are needed. Heat of vapcrization data for ; isopropyl diphenyl, orthote rphenyl, metaterphenyl, parate rphenyl, and diphenyl ; at absolute pressures of four, two, one and onehalf inches of mercury were

Burkhardt

1958-01-01

77

On the Way to Determination of the Vapor-Pressure Curve of Pure Water  

NASA Astrophysics Data System (ADS)

The determination of the physical properties of pure water, especially the vapor-pressure curve of water, is one of the major issues identified by the Consultative Committee for Thermometry of the International Committee for Weights and Measures (CIPM) to improve the accuracy of the national references in humidity. At the present time the saturation-pressure data, corresponding to ice or liquid-vapor equilibrium, at low temperature are scarce and unreliable. This study presents new measurements of vapor and sublimation pressures of, respectively, water and ice, using a static apparatus. Prior to saturation-pressure measurements, the temperature and pressure sensors of the static apparatus were calibrated against reference gauges in use at the LNE- CETIAT laboratories. The effect of thermal transpiration has been studied. The explored temperature range lies between 250 K and 374 K, and the pressure range between 70 Pa and 105 Pa. An automatic data acquisition program was developed to monitor the pressure and temperature. The obtained results have been compared with available literature data. The preliminary uncertainty budget took into account several components: pressure measurements, temperature measurements, and environmental error sources such as thermal transpiration and hydrostatic correction.

Mokdad, S.; Georgin, E.; Mokbel, I.; Jose, J.; Hermier, Y.; Himbert, M.

2012-09-01

78

A theoretical model of laser ionization of alkali vapors based on resonance saturation  

NASA Astrophysics Data System (ADS)

A theoretical model of the ionization that results from extended laser saturation of an atomic resonance transition within a dense alkali vapor has been developed. Although this model includes all of the essential collisional-radiative interactions, nevertheless it leads to relatively simple analytical relations that predict the ionization time history to within 20% of that calculated by an extensive laser ionization based on resonance saturation computer code in the case of sodium. When allowance is made for the temporal and spatial nature of a realistic laser pulse, the apparent ionization time has been shown to be approximately double that of the value predicted on the basis of a steplike, flat laser pulse.

Measures, R. M.; Cardinal, P. G.; Schinn, G. W.

1981-03-01

79

Vapor pressure measurements of volatile transition-metal complexes  

SciTech Connect

The design and construction of a special cell to measure the vapor pressure of air-sensitive compounds is described. Cyclohexane was used to calibrate this device prior to the measurement of vapor pressure as a function of temperature for several third row transition metal complexes. HIr(PF{sub 3}){sub 4} was found to be stable for hours at 86{degree}C, developing a vapor pressure of 711 torr. (HFACAC) AuMe{sub 2} showed a pressure of 140 torr at 58{degree}C while Pt(PF{sub 3}){sub 4} displayed 240 torr at 55{degree}C. The vapor pressure curves and linear equations are given for all three compounds. Attempts to achieve higher pressures by heating of latter two compounds were unsuccessful; thermal decomposition was evident above 65{degree}C. Addition of excess trifluorophosphine to the platinum complex to slow the decomposition was largely ineffective. 8 refs., 6 figs.

Sanner, R.D.; Satcher, J.H. Jr.

1989-09-18

80

Coal reservoir saturation: Impact of temperature and pressure  

SciTech Connect

Methane adsorption isotherms measured for a series of coals with varying rank at a wide range of temperatures and pressures allows the prediction of the change in sorption capacity as a function of tectonic history. Changes in sorption capacity in response to declining pressure and temperature associated with uplift may increase or decrease the capacity of the coal and, if the coal is initially saturated, result in excess gas or a deficiency of gas (undersaturation). Assuming reasonable geothermal and pressure gradients, our data indicate that the sorption capacity will generally decrease with uplift and associated exhumation, suggesting that an initially gas-saturated coal will desorb gas during uplift of the reservoir. The desorbed gas would be available for migration and/or, potentially, resaturation of an undersaturated coal. Our results argue against the generally accepted theory that undersaturation of coal reservoirs results from an increase in the sorption capacity with uplift except for coals at such high pressures that the isotherms are essentially flat or for very high pressure and geothermal gradients.

Bustin, A.M.M.; Bustin, R.M. [University of British Columbia, Vancouver, BC (Canada). Dept. of Earth & Ocean Science

2008-01-15

81

Investigation of the adiabatic expansion of water vapor from the saturation line in laval nozzles  

Microsoft Academic Search

The effectiveness of the operation of a jet thermal pump (i) depends on the perfection of its basic subassemblies, one of which is the nozzle for the expansion of water vapor from the saturation line into the two-phase region. As the investigations of (2) show, when thermal differentials of more than 4 kJ\\/kg are acting in nozzles, i.e., when a

. K. Karasev; V. V. Vazinger; G. S. Mingaleeva; E. I. Trubkin

1977-01-01

82

Water Vapor Saturation at Low Altitudes around Mars Aphelion: A Key to Mars Climate?  

Microsoft Academic Search

The combined analysis of microwave temperature and water profiling of the Mars atmosphere indicates that low- to mid-latitude water vapor saturation typically occurs at much lower altitudes (below 10 km) during northern spring\\/summer than observed during this Mars aphelion season in the dusty, warm period of Viking observations (above 25 km). Temperatures profiles of the 060 km global Mars atmosphere

R. T. Clancy; A. W. Grossman; M. J. Wolff; P. B. James; D. J. Rudy; Y. N. Billawala; B. J. Sandor; S. W. Lee; D. O. Muhleman

1996-01-01

83

Controlling the vapor pressure of a mercury lamp  

DOEpatents

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.

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

1988-05-24

84

LOX vaporization in high-pressure, hydrogen-rich gas  

NASA Astrophysics Data System (ADS)

LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

Litchford, Ron J.; Jeng, San-Mou

1990-07-01

85

Development of vapor pressure in FR4-copper composite material during solder reflow process  

NASA Astrophysics Data System (ADS)

This paper presents a finite element (FE) methodology for predicting the distribution of vapor pressure in a simple FR4-copper composite material when it is heated up to 215C. A general purpose finite element software was used to develop a two-dimensional plane strain model of the composite material. FE simulation of transient moisture absorption was performed to predict the distribution of wetness fraction in the material after pre-conditioning at an 85C/85%RH environment for 15 days. FE simulation of transient moisture desorption was carried out at the peak solder reflow temperature of 215C to predict new distribution of wetness fraction in the material. The results of the moisture desorption analysis were used to compute the magnitude of vapor pressure in the material and its distribution at 215C. It was found that the moisture in the material redistributes itself during solder reflow. The moisture concentration in the area close to the FR4-copper interface below the longer copper trace increases during the solder reflow. The magnitude of the vapor pressure in 70% of the FR4 and near the FR4-copper interface below the lower copper trace is closed to the saturation pressure of water vapor at 215C. The distribution of the vapor pressure in the material is in similar fashion as the new distribution of wetness fraction after the moisture desorption analysis.

Kamsah, Nazri; Tamin, Mohd Nasir; Kamar, Haslinda Mohamed; Lahuri, Hidayatunnur; Wagiman, Amir Nur Rashid

2012-06-01

86

Vapor pressures and thermodynamic properties of UF/sub 4/  

SciTech Connect

Various thermodynamic data generated at the Oak Ridge Gaseous Diffusion Plant for uranium tetrafluoride is discussed. The data includes vapor pressure and entropy and enthalpy of fusion data. Agreement with data generated by others is also discussed. Limited data on the thermodynamic values for vaporization of uranium tetrafluoride is included in tabular form.

Leitnaker, J.M.

1983-06-01

87

Water-Vapor Pressure Control in a Volume.  

National Technical Information Service (NTIS)

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 diffusio...

J. J. Scialdone

1978-01-01

88

A Study of the Composition of Water Vapor Saturated Natural Gas, as Applied to Elucidation of the Nature of Vapor-Gas Thermal Phenomena  

Microsoft Academic Search

The composition of water vapor saturated gases of various temperatures from reserve wells of Yangantau health resort was studied. The dependence of the concentration and composition of organic substances from the vapor condensate and of the extent of thermal oxidative degradation of the shale organic matter on the rock temperature in the heating zone was examined.

G. R. Anpilogova; R. A. Khisamutdinov; Yu. I. Murinov; R. M. Kharasov; I. Sh. Khuramshin; E. G. Galkin

2004-01-01

89

46 CFR 154.445 - Design vapor pressure.  

Code of Federal Regulations, 2012 CFR

...Design, Construction and Equipment Independent Tank Type B § 154.445 Design vapor pressure. If the surfaces of an independent tank type B are mostly flat surfaces, the Po must not exceed 69 kPa gauge (10...

2012-10-01

90

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

ERIC Educational Resources Information Center

|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

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

2007-01-01

91

The Effect of Films on the Capillary Pressure - Saturation Relationship  

NASA Astrophysics Data System (ADS)

The hysteretic dependence of capillary pressure (Pc) on saturation (S) indicates that additional state variables are needed to describe multiphase flow behavior in porous media. Previous studies have shown that the observed hysteresis is a projection of a higher-dimensional surface that depends on interfacial area per volume, as an additional state variable. However, these studies have not addressed the affected of films on the Pc-S relationship. In this study, we use laser scanning confocal microscopy to image the three-dimensional (3D) fluid distributions of two immiscible fluids in a simple wedge-shaped channel. We find that entrained films of wetting phase affect the P-S relationship during both drainage and imbibition and that these extensions of the fluid-fluid interface increase the interaction among the wetting, non-wetting, and solid phases.
Smooth-walled and rough-walled wedge-shaped channels were fabricated using two different approaches: 1) two-photon polymerization by femtosecond laser and 2) broadband photolithography. Both techniques use UV-sensitive photoresist (SU-8) to construct an all-SU-8 micromodel containing a wedge-shaped channel that is 100 ?m wide at the outlet and 20 ?m wide at the inlet with a constant depth of 40 ?m. A Zeiss LSM 710 Confocal Microscope was used for image the water (wetting phase) and air (non-wetting phase) distributions within the micromodel. By labeling the wetting phase with a fluorophore (Alex Fluor-488 water solution 1%w.t.), the water-air interfaces are clearly visible in the confocal microscopy images. The samples were initially saturated with water. A series of drainage and imbibition cycles were performed by incrementing or decrementing the air pressure. At each pressure, the system was allowed to equilibrate and then a stack of scans in depth was collected to acquire the 3D fluid distribution for a given pressure. The confocal images were analyzed to extract the volume saturation of air and water, the curvature of the three-dimensional fluid-air interface, as well as the interfacial area per volume.
Hysteretic dependence of the capillary pressure (Pc) on the volume saturation (Sv) was observed even though the wedge-shaped channel has no complex geometry. The Pc - Sv hysteresis with and without films was compared. When films were present, higher capillary pressure was needed to drain the wetting phase. The film provided additional resistance during drainage and additional forces during imbibition.
Because Sv indicates the wetting phase volume variation, the energy ?E cost to move the interface was calculated from the Pc - Sv graph between pressure steps. The change in surface area ?A between pressure steps was calculated from the saturation Sv. Linear relationships were found between ?E and ?A for drainage and imbibition. The slopes of the ?E - ?A lines with film are higher than that without film, suggesting that the system expends additional energy to move fluid-fluid interfaces when films are present.
Acknowledgments: This research is supported by the National Science Foundation (0509759-EAR and 0911284-EAR).

Liu, Y.; Pyrak-Nolte, L. J.; Nolte, D. D.; Giordano, N. J.

2009-12-01

92

Development of a quasi-adiabatic calorimeter for the determination of the water vapor pressure curve  

NASA Astrophysics Data System (ADS)

Progress in the knowledge of the water saturation curve is required to improve the accuracy of the calibrations in humidity. In order to achieve this objective, the LNE-CETIAT and the LNE-CNAM have jointly built a facility dedicated to the measurement of the saturation vapor pressure and temperature of pure water. The principle is based on a static measurement of the pressure and the temperature of pure water in a closed, temperature-controlled thermostat, conceived like a quasi-adiabatic calorimeter. A copper cell containing pure water is placed inside a temperature-controlled copper shield, which is mounted in a vacuum-tight stainless steel vessel immersed in a thermostated bath. The temperature of the cell is measured with capsule-type standard platinum resistance thermometers, calibrated with uncertainties below the millikelvin. The vapor pressure is measured by calibrated pressure sensors connected to the cell through a pressure tube whose temperature is monitored at several points. The pressure gauges are installed in a thermostatic apparatus ensuring high stability of the pressure measurement and avoiding any condensation in the tubes. Thanks to the employment of several technical solutions, the thermal contribution to the overall uncertainty budget is reduced, and the remaining major part is mainly due to pressure measurements. This paper presents a full description of this facility and the preliminary results obtained for its characterization.

Mokdad, S.; Georgin, E.; Hermier, Y.; Sparasci, F.; Himbert, M.

2012-07-01

93

Apparatus of the Vapor-pressure Measurements for Natural Refrigerants  

NASA Astrophysics Data System (ADS)

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 100? platinum resistance thermometer calibrated against ITS-90 using a 25? 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.

Higuchi, Satoru; Higashi, Yukihiro

94

Preliminary assessment of condensation behavior for hydrocarbon-vapor expansions which cross the saturation line near the critical point  

SciTech Connect

Previous analyses of binary cycles for conversion of geothermal energy from moderate temperature resources to electrical energy have shown potential gains in net geofluid effectiveness on the order of 8%, resulting from selection of turbine-expansion processes whose equilibrium states pass through the two-phase region. If condensation occurs, this gain could be reduced or eliminated by the resulting loss in turbine efficiency. Experience with many fluids, however, indicates that vapor supersaturation permits metastable pure-vapor states to exist at temperatures considerably below the saturation temperature at a given pressure; thus, by better understanding the condensation process, and properly structuring the cycle, substantial performance gains may be possible. The purpose of the present study was to assess the probability for attaining this performance gain by estimating the extent of condensation which might be expected during such an expansion of isobutane vapor. The study indicated that turbine performance should not be degraded significantly for the turbine expansions considered, and that a large fraction of the gain in geofluid effectiveness identified previously is potentially achievable.

Demuth, O.J.

1983-01-01

95

40 CFR 796.1950 - Vapor pressure.  

Code of Federal Regulations, 2010 CFR

...saturation procedure is to be used. (ii) With respect to the isoteniscope method, if compounds that boil close to or form azeotropes with the test material are present, it is necessary to remove the interfering compounds and use pure test...

2010-07-01

96

40 CFR 796.1950 - Vapor pressure.  

Code of Federal Regulations, 2010 CFR

...saturation procedure is to be used. (ii) With respect to the isoteniscope method, if compounds that boil close to or form azeotropes with the test material are present, it is necessary to remove the interfering compounds and use pure test...

2009-07-01

97

Top-gated chemical vapor deposition grown graphene transistors with current saturation.  

PubMed

Graphene transistors are of considerable interest for radio frequency (rf) applications. In general, transistors with large transconductance and drain current saturation are desirable for rf performance, which is however nontrivial to achieve in graphene transistors. Here we report high-performance top-gated graphene transistors based on chemical vapor deposition (CVD) grown graphene with large transconductance and drain current saturation. The graphene transistors were fabricated with evaporated high dielectric constant material (HfO(2)) as the top-gate dielectrics. Length scaling studies of the transistors with channel length from 5.6 ?m to 100 nm show that complete current saturation can be achieved in 5.6 ?m devices and the saturation characteristics degrade as the channel length shrinks down to the 100-300 nm regime. The drain current saturation was primarily attributed to drain bias induced shift of the Dirac points. With the selective deposition of HfO(2) gate dielectrics, we have further demonstrated a simple scheme to realize a 300 nm channel length graphene transistors with self-aligned source-drain electrodes to achieve the highest transconductance of 250 ?S/?m reported in CVD graphene to date. PMID:21548551

Bai, Jingwei; Liao, Lei; Zhou, Hailong; Cheng, Rui; Liu, Lixin; Huang, Yu; Duan, Xiangfeng

2011-05-06

98

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 January 1993--31 March 1993  

SciTech Connect

The vapor pressure correlations that exist at present for high molecular weight organics are very crude and they are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. It has been concluded that the saturation method holds significant promise as technique for measuring vapor pressures of pure components in the correct molecular weight regime. There are several aspects of experimental design that need further work in to improve performance. Most critical is the saturator device.

Suuberg, E.M.

1993-07-01

99

Subatmospheric vapor pressures evaluated from internal-energy measurements  

NASA Astrophysics Data System (ADS)

Vapor pressures were evaluated from measured internal-energy changes in the vapor+liquid two-phase region, ? U (2). The method employed a thermodynamic relationship between the derivative quantity (? U (2)/? V) T and the vapor pressure ( p ?) and its temperature derivative (? p/? T)?. 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 ? for this substance. It was also applied to evaluate published p ? data which are in disagreement by more than their claimed uncertainty.

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

1997-01-01

100

Structural rearrangements in a lamellar diblock copolymer thin film during treatment with saturated solvent vapor.  

PubMed

We have investigated the structural changes in thin films of lamellar poly(styrene-b-butadiene) diblock copolymers during treatment with saturated cyclohexane vapor, a solvent slightly selective for polybutadiene. Using real-time, in-situ grazing-incidence small-angle X-ray scattering (GISAXS), the swelling and the rearrangement of the lamellae were investigated with a time resolution of a few seconds, and the underlying processes on the molecular level were identified. After a few minutes in vapor, a transient state with a more well-defined and more long-range ordered lamellar orientation was encountered. Additional parallel lamellae formed which we attribute to the increased degree of coiling of the polymers in the swollen state. Eventually, the film became disordered. These changes are attributed to the increased mobility of the swollen polymers and the gradually decreasing segment-segment interaction parameter in the film as solvent is absorbed. PMID:20305742

Di, Zhenyu; Posselt, Dorthe; Smilgies, Detlef-M; Papadakis, Christine M

2010-01-12

101

Evidence of water vapor in excess of saturation in the atmosphere of Mars.  

PubMed

The vertical distribution of water vapor is key to the study of Mars' hydrological cycle. To date, it has been explored mainly through global climate models because of a lack of direct measurements. However, these models assume the absence of supersaturation in the atmosphere of Mars. Here, we report observations made using the SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) instrument onboard Mars Express that provide evidence of the frequent presence of water vapor in excess of saturation, by an amount far surpassing that encountered in Earth's atmosphere. This result contradicts the widespread assumption that atmospheric water on Mars cannot exist in a supersaturated state, directly affecting our long-term representation of water transport, accumulation, escape, and chemistry on a global scale. PMID:21960630

Maltagliati, L; Montmessin, F; Fedorova, A; Korablev, O; Forget, F; Bertaux, J-L

2011-09-30

102

Effects of saturation medium and pressure on strength parameters of Latrobe Valley brown coal: Carbon dioxide, water and nitrogen saturations  

Microsoft Academic Search

Adsorption of carbon dioxide (CO2) into coal matrix causes significant change in its chemical and physical structure, resulting in negligible permeability values and overall strength reduction. The main objective of this study is to investigate the effects of water, nitrogen (N2) and CO2 saturations at different saturation pressures on the strength of brown coal using uniaxial experiments. A series of

M. S. A. Perera; P. G. Ranjith; M. Peter

103

A numerical study of high-pressure droplet vaporization  

SciTech Connect

This paper reports that the evaporation of single, spherical fuel droplets in a high-pressure, high-temperature environment has been studied numerically. The model is fully transient in both the liquid and the vapor phases. Transport properties are functions of temperature, pressure, and composition, and vary throughout the liquid droplet and the vapor boundary layer. Equilibrium at the liquid-vapor interface is calculated using the Peng-Robinson equation of state, and accounts for diffusion of the gas into the liquid droplet. The Peng-Robinson equation of state is also used to calculate the enthalpy of vaporization of the fuel species as well as the liquid and vapor mixture densities. The proposed model is compared with data obtained for a variety of liquids. The comparisons include the predictions of the critical mixing state, droplet vaporization rate, and droplet temperature. Transient effects in both the liquid and vapor phases are found to have a large effect on the droplet heatup and vaporization process.

Curtis, E.W.; Farrell, P.V. (Wisconsin Univ., Madison, WI (United States). Dept. of Mechanical Engineering)

1992-08-01

104

Fiber optic sensor for simultaneous oxygen saturation and blood pressure measurement  

NASA Astrophysics Data System (ADS)

This paper presents preliminary sensor designs and reports initial test results for the implementation of real-time simultaneous oxygen saturation and blood pressure measurement. Closed-lumen catheter-type in-vivo sensing schemes incorporate a proven, well-established distal-tipped fiberoptic pressure sensor. Spectroscopic oxygen saturation determination is multiplexed with pressure sensing in a shared transceiver approach, and oxygen saturation sensitivity may be enhanced via synchronous pressure detection. Operating principles for pressure and oxygen saturation measurement are described, and various catheter side-port oxygen saturation sensor designs are explored. Experimental methods and results are presented, and sensor sensitivity is examined.

Anderson, Charles D.; Vokovitch, Dan; Wlodarczyk, Marek T.

1992-04-01

105

A numerical study of high-pressure droplet vaporization  

NASA Astrophysics Data System (ADS)

The evaporation of single, spherical fuel droplets in a high-pressure, high-temperature environment has been studied numerically. The model is fully transient in both the liquid and the vapor phases. Transport properties are functions of temperature, pressure, and composition, and vary throughout the liquid droplet and the vapor boundary layer. Equilibrium at the liquid-vapor interface is calculated using the Peng-Robinson equation of state, and accounts for diffusion of the gas into the liquid droplet. The Peng-Robinson equation of state is also used to calculate the enthalpy of vaporization of the fuel species as well as the liquid and vapor mixture densities. The proposed model is compared with data obtained for a variety of liquids. Transient effects in both the liquid and vapor phases are found to have a large effect on the droplet heatup and vaporization process. At very high temperature and pressure conditions the droplets were found to reach their thermodynamic critical mixing point in a totally transient process.

Curtis, E. W.; Farrell, P. V.

1992-08-01

106

Vapor Pressure Isotope Effect in Liquid and Solid Ammonia.  

National Technical Information Service (NTIS)

The vapor pressures of the isotopic ammonia sup 14 NH sub 3 , sup 14 ND sub 3 and sup 15 NH sub 3 have been measured at temperatures between 163K and 240K by differential manometric technique in a precision cryostat. The triple point pressures were found ...

T. V. King T. Ishida

1986-01-01

107

Vapor Pressure, Speed of Sound, and PVT-Properties of R-404a in the Vapor Phase  

NASA Astrophysics Data System (ADS)

The density (300 363 K, up to 3.5 MPa) and speed of sound (293 373 K, 7.5 480 kPa) in gaseous R-404a have been studied by an isochoric piezometer method and an ultrasonic interferometer, respectively. The pressures of the saturated vapor along the dew line were measured from 298 to 330 K. The experimental uncertainties of the temperature, pressure, density, and speed-of-sound measurements were estimated to be within 20 mK, 1.5 kPa, 0.15%, and (0.1 0.2)%, respectively. On the basis of the obtained data, the isobaric molar heat capacity of R-404a was calculated for the ideal-gas state. An eight-coefficient Benedict Webb Rubin equation of state has been developed for the gaseous phase of R-404a.

Gruzdev, V. A.; Komarov, S. G.; Stankus, S. V.

2008-04-01

108

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric uranium dioxide at high temperatures  

Microsoft Academic Search

Vapor pressures and vapor compositions in equilibrium with a hypostoichiometric uranium-plutonium dioxide condensed phase (U\\/sub 1-y\\/Pu\\/sub y\\/)O\\/sub 2-x\\/, as functions of T, x, and y, have been calculated for 0.0 less than or equal to x less than or equal to 0.1, 0.0 less than or equal to y less than or equal to 0.3, and for the temperature range

D. W. Green; J. K. Fink; L. Leibowitz

1982-01-01

109

A new generalized correlation for accurate vapor pressure prediction  

NASA Astrophysics Data System (ADS)

An accurate knowledge of the vapor pressure of organic liquids is very important for the oil and gas processing operations. In combustion modeling, the accuracy of numerical predictions is also highly dependent on the fuel properties such as vapor pressure. In this Letter, a new generalized correlation is proposed based on the Lee-Kesler's method where a fuel dependent parameter 'A' is introduced. The proposed method only requires the input parameters of critical temperature, normal boiling temperature and the acentric factor of the fluid. With this method, vapor pressures have been calculated and compared with the data reported in data compilation for 42 organic liquids over 1366 data points, and the overall average absolute percentage deviation is only 1.95%.

An, Hui; Yang, Wenming

2012-08-01

110

Comparison of Residual Saturation and Capillary Pressure Model for Granular Materials with UNSODA Data  

SciTech Connect

The capillary pressure model correlates drainage and imbibition data from the UNSODA database, provided that the data incorporate the entry head, a minimum displacement required for drainage to begin. According to the model, the imbibition pressure equals the drainage pressures at a critical minimum saturation of 0.301; below this critical saturation, no additional reversible drainage should occur. Some of the UNSODA data sets had a minimum saturation approximately half this value. The difference is attributed to the presence of fissures, which would lower the residual wetting and critical minimum saturations by reducing the fraction of the void volume controlled by capillary pores. If the UNSODA saturations are adjusted for this discrepancy, a probability distribution of minimum saturations for each data set peaks near the predicted critical minimum saturation. Maximum saturations for each data set have a peak near the predicted residual nonwetting saturation of 0.884.

LAURINAT, JAMESE.

2004-11-01

111

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric plutonium dioxide at high temperatures  

SciTech Connect

Vapor pressures and vapor compositions have been calculated for 1500 less than or equal to T less than or equal to 4000/sup 0/K. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen-potential model extended into the liquid region to obtain the partial pressures of O/sub 2/, O, Pu, PuO and PuO/sub 2/. The calculated oxygen pressures increase very rapidly as stoichiometry is approached. At least part of this increase is a consequence of the exclusion of Pu/sup 6 +/ from the oxygen-potential model. No reliable method was found to estimate the importance of this ion. As a result of large oxygen potentials at high temperatures, extremely high total pressures that produced unreasonably high vapor densities were calculated. The highest temperature was therefore limited to 400 K, and the range of oxygen-to-metal ratios was limited to 1.994 to 1.70. These calculations show that vapor in equilibrium with hypostoichiometric plutonium dioxide is poorly approximated as PuO/sub 2/ for most of the temperture and composition range of interest. The vapor is much more oxygen-rich than the condensed phase. Implications for the (U,Pu)O/sub 2-x/ system are discussed. (DLC)

Green, D.W.; Fink, J.K.; Leibowitz, L.

1982-01-01

112

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standards: Pressure relief devices in gas/vapor...AND DISPOSAL FACILITIES Air Emission Standards for Equipment... § 264.1054 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each...

2013-07-01

113

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standards: Pressure relief devices in gas/vapor...AND DISPOSAL FACILITIES Air Emission Standards for Equipment... § 265.1054 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each...

2013-07-01

114

Experimental Characterization of Redox Changes During Degassing of a Vapor Saturated Magma: Redox Exchanges Between H-O-Fe Species  

NASA Astrophysics Data System (ADS)

The redox state of a magma reaching the surface is generally thought to be buffered by its iron redox ratio during ascent, reflecting therefore that of its source region. Only recently, the role of volatiles degassing on redox state of silicic magmas has been quantitatively addressed using numerical modelling. In these iron-poor magmatic systems, oxygen fugacity (fO2) is almost dominated by the chemical potential of the H2 and H2O volatile components. Because water is several orders of magnitude more soluble than molecular hydrogen in molten silicate, it was found that the ratio of their chemical potential dramatically changes during closed system degassing leading to an increase in fO2 of 2 orders of magnitude. We present here the results of an experimental test of such an oxidation event associated to the decompression of silicic melts saturated in volatiles. A peralkaline synthetic composition containing 2-4wt percent of dissolved iron oxides is used as starting material. Experiments are performed in cold seal pressure vessels pressurized with pre-mixed argon and hydrogen bottles. All experiments are equilibrated under water-saturated conditions at 800C and variable pressures between 200 MPa and 25 MPa. Experiments were ended by rapid drop quench. Three oxygen fugacity conditions were investigated by using pure Argon (NNO+3) and two Ar-H2 mixtures buffering fO2 conditions at NNO+1.5 and NNO. Water content was determined using infrared spectroscopy and Karl-Fisher titration and the iron redox ratio was measured by wet chemistry. All run products are free of crystals. Time series experiments at fixed pressure were performed to determine the equilibrium dependence of iron redox ratios on pressure. Decompression experiments were performed from an equilibrated vapor-saturated melt at 200 MPa, lasted from few minutes to few hours, and were quenched at 100 MPa to 25 MPa. The measured iron redox ratios after decompression do not considerably differ from the ones before decompression. A slight oxidation is however noticed for some experiments, which can correspond to 0.7 log- units of fO2 increase in the most favorable cases. We conclude that a "Le Chatelier effect" most likely dominates and restricts the fO2 increase that is otherwise expected to be of ~2 log units in an iron-free melt: The increase in the fugacity ratios of H2O/H2 due to degassing upon decompression is restricted by H2 produced during oxidation of ferrous iron by water. The importance of this "Le Chatelier effect" strongly depends on the fO2 conditions prior to degassing.

Mollard, E.; Gaillard, F.; Scaillet, B.

2007-12-01

115

Prediction of two-phase capillary pressure saturation relationships in fractional wettability systems  

Microsoft Academic Search

Capillary pressure\\/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting porous media. Few capillary pressure\\/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natural subsurface. This work presents a new two-phase capillary pressure\\/saturation model for application to the prediction of primary drainage and imbibition

Denis M. O'Carroll; Linda M. Abriola; Catherine A. Polityka; Scott A. Bradford; Avery H. Demond

2005-01-01

116

Prediction of two-phase capillary pressuresaturation relationships in fractional wettability systems  

Microsoft Academic Search

Capillary pressure\\/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting porous media. Few capillary pressure\\/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natural subsurface. This work presents a new two-phase capillary pressure\\/saturation model for application to the prediction of primary drainage and imbibition

Denis M. O'Carroll; Linda M. Abriola; Catherine A. Polityka; Scott A. Bradford; Avery H. Demond

2005-01-01

117

Psychrometric and ventilation constraints for vapor pressure deficit control  

Microsoft Academic Search

Constraints on air temperature, dewpoint temperature and ventilation rate in plant growth and propagation chambers under vapor pressure deficit (VPD) control are presented. These constraints apply to any controlled environment space subjected to significant radiation in which both air temperature and humidity can be simultaneously manipulated. Defining relations and logic necessary to implement two methods of VPD control (VPDair vs.

S Zolnier; R. S Gates; J Buxton; C Mach

2000-01-01

118

Molecular weight of aquatic fulvic acids by vapor pressure osmometry  

Microsoft Academic Search

The molecular weights of aquatic fulvic acids extracted from five rivers were determined by vapor pressure osmometry with water and tetrahydrofuran as solvents. The values obtained ranged form 500 to 950 daltons, indicating that the molecular weights of aquatic fulvic acids are not as great as has been suggested in some other molecular weight studies. The samples were shown to

G. R. Aiken; R. L. Malcolm

1987-01-01

119

46 CFR 154.436 - Design vapor pressure.  

Code of Federal Regulations, 2012 CFR

...Semi-Membrane Tanks § 154.436 Design vapor pressure. The Po of a semi-membrane tank must not exceed 24.5 kPa gauge...unless special approval by the Commandant (CG-ENG) allows a Po between 24.5 kPa gauge (3.55 psig) and 69 kPa...

2012-10-01

120

46 CFR 154.419 - Design vapor pressure.  

Code of Federal Regulations, 2012 CFR

... Integral Tanks § 154.419 Design vapor pressure. The Po of an integral tank must not exceed 24.5 kPa gauge (3...unless special approval by the Commandant (CG-ENG) allows a Po between 24.5 kPa gauge (3.55 psig) and 69 kPa...

2012-10-01

121

46 CFR 154.426 - Design vapor pressure.  

Code of Federal Regulations, 2012 CFR

... Membrane Tanks § 154.426 Design vapor pressure. The Po of a membrane tank must not exceed 24.5 kPa gauge (3...unless special approval by the Commandant (CG-ENG) allows a Po between 24.5 kPa gauge (3.55 psig) and 69 kPa...

2012-10-01

122

Hydrogen Vapor Pressures from 4 to 30 K: A Review.  

National Technical Information Service (NTIS)

The following properties for the hydrogens from 4 to 30 exp 0 K are reviewed: liquid-gas and solid-gas vapor pressures, triple-point values, virial coefficients, liquid and solid densities, and heats of transformation. We have correlated these properties ...

P. C. Souers C. K. Briggs J. W. Pyper R. T. Tsugawa

1977-01-01

123

A nonlinear regression analysis for estimating low-temperature vapor pressures and enthalpies of vaporization applied to refrigerants  

Microsoft Academic Search

A new method is presented to extrapolate experimental vapor pressures down to the triple Point. The method involves a nonlinear regression analysis based on the Clausius Clapeyron equation and a simple relation for the enthalpy of vaporization Triple-point pressures and vapor pressures up to 0.1 0.2 MPa are estimated for R125, R32, R143a, R134a, R152a, R123, R124, and ammonia; they

R. Tillner-Roth

1996-01-01

124

Model for Residual Saturations and Capillary Imbibition and Drainage Pressures in Granular Materials  

SciTech Connect

A pore saturation model expresses the capillary pressure as a function of a characteristic pore pressure and the wetting phase saturation. Singularity analyses of the total energies of the wetting and nonwetting phases give the residual saturations for the two phases. The total energy consists of a potential term and a work term associated with the effective pressure gradient for each phase. The derived residual wetting saturation is 0.236, and the derived residual nonwetting saturation is 0.884. The model includes separate pressures for imbibition and drainage to account for capillary hysteresis. In the model, the pressure gradient for the wetting phase defines the imbibition pressure, and the nonwetting phase pressure gradient defines the drainage pressure. At the residual nonwetting saturation, the two pressures differ by the characteristic pore pressure. The two pressures coincide at a critical minimum saturation of 0.301. The model also includes an entry head to account for the minimum force required for drainage to begin. The model uses a single fitting parameter, a characteristic pore pressure, which can be related to a characteristic pore diameter.

LAURINAT, JAMESE

2004-11-01

125

Pressure (Or No Royal Road)  

ERIC Educational Resources Information Center

|Discusses how difficult the various problems of pressure, partial pressure, gas laws, and vapor pressure are for students. Outlines the evolution of the concept of pressure, the gas equation for a perfect gas, partial pressures, saturated vapor pressure, Avogadro's hypothesis, Raoult's law, and the vapor pressure of ideal solutions. (JR)|

Bradley, J.

1973-01-01

126

Pore-scale modeling of transient and steady-state vapor diffusion in partially-saturated porous media  

SciTech Connect

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 a mechanistic pore-scale model of these processes under steady-state conditions in which condensation and evaporation on the liquid island were equal. The vapor diffusion rate was significantly enhanced by these liquid island processes by up to an order of magnitude compared to a dry porous media. However, vapor transport by diffusion is often complicated by transient effects, such as in drying applications, in which net evaporation of liquid may further augment the vapor flux from diffusion. The influence of transient effects on the enhancement factors for vapor diffusion is evaluated in this paper. In addition, the effect of vapor pressure lowering on the enhancement factor and on porescale vapor fluxes is shown.

Webb, S.W.

1998-05-01

127

Vapor pressure critical amplitudes from the normal boiling point  

NASA Astrophysics Data System (ADS)

The authors propose a method to estimate the two first critical amplitudes for the vapor pressure of a fluid in terms only of the reduced pressure, Pbr=Pb/Pc, and temperature, Tbr=Tb/Tc, of the normal boiling point. The method is based on the fact that the product (1-Tr)Pr presents a maximum near the critical region. Based on a study of 43 fluids, the authors found that the reduced pressure and temperature of that maximum can be obtained from simple relations in terms of the parameter h?Tbr ln Pbr/(Tbr-1). These relations are checked against additional data for 1608 fluids.

Velasco, S.; Romn, F. L.; White, J. A.; Mulero, A.

2007-04-01

128

46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.  

Code of Federal Regulations, 2012 CFR

...BULK LIQUEFIED GASES Design, Construction and Equipment...Systems § 154.405 Design vapor pressure (Po ) of a cargo tank. (a) The design vapor pressure (Po ...The cargo tank has no temperature control for the...

2012-10-01

129

46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Design vapor pressure (Po) of a cargo tank...VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po ) of a...

2011-10-01

130

40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standards: Pressure relief devices in gas/vapor service...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL...Sources) § 61.242-4 Standards: Pressure relief devices in gas/vapor...

2013-07-01

131

Method and apparatus to measure vapor pressure in a flow system  

DOEpatents

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.

Grossman, Mark W. (Belmont, MA); Biblarz, Oscar (Swampscott, MA)

1991-01-01

132

Vapor-liquid equilibria of cyclohexanol with carbon dioxide, ethane, or nitrogen at elevated pressures  

SciTech Connect

Vapor-liquid equilibrium (VLE) data were measured for the binary systems of cyclohexanol with carbon dioxide, ethane, or nitrogen at temperatures from 333.15 K to 453.15 K and pressures up to 190 bar. The saturated vapor compositions were correlated with the density of the light components. Henry`s constants of the gases dissolved in cyclohexanol were calculated with the aid of the Krichevsky-Ilinskaya equation. The new VLE data were also correlated by the Peng-Robinson and the Patel-Teja equations of state. In general, the Patel-Teja equation incorporating the one-fluid, two-parameter van der Waals mixing rule yielded the best representation.

Chen, J.T.; Lee, M.J. [National Taiwan Inst. of Tech., Taipei (Taiwan, Province of China). Dept. of Chemical Engineering

1996-03-01

133

An empirical model for estimating the saturation pressures of crude oils  

Microsoft Academic Search

Recently, there has been an increasing interest in enhanced oil recovery (EOR) calculations of saturation pressures when various gases contact crude oils. Equations of state are usually used for calculations of saturation pressure at initial condition of discovery or later during EOR design. However, the equations of state results are not reliable unless they are properly tuned using some experimental

Adel M. Elsharkawy

2003-01-01

134

PREDICTION OF TWO-PHASE CAPILLARY PRESSURE-SATURATION RELATIONSHIPS IN FRACTIONAL WETTABILITY SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Capillary pressure/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting soils. Few capillary pressure/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natura...

135

Use of a Swelling Retention Agent in Wet-Fixation by High Pressure Saturated Steam  

Microsoft Academic Search

This paper presents a study of one-step wet-fixation of trimethylolmelamine with a swelling retention agent (sodium nitrate) in cotton printcloth by saturated high pressure steam. This process produces fabrics with high durable press ratings and better strength retention compared to conventional padded, dried, and cured fabrics. The advantage of using high pressure saturated steam is the reduction in time to

Allan H. Lambert; Ronald A. Holser; Robert J. Harper

1986-01-01

136

Vapor pressure and vapor fractionation of silicate melts of tektite composition  

USGS Publications Warehouse

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.

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

1964-01-01

137

A nonlinear regression analysis for estimating low-temperature vapor pressures and enthalpies of vaporization applied to refrigerants  

NASA Astrophysics Data System (ADS)

A new method is presented to extrapolate experimental vapor pressures down to the triple Point. The method involves a nonlinear regression analysis based on the Clausius Clapeyron equation and a simple relation for the enthalpy of vaporization Triple-point pressures and vapor pressures up to 0.1 0.2 MPa are estimated for R125, R32, R143a, R134a, R152a, R123, R124, and ammonia; they generally agree with available experimental data within their uncertainty, Equations for the enthalpy of vaporization which describe this property fairly well at low temperatures are obtained as a byproduct.

Tillner-Roth, R.

1996-11-01

138

46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405 Section 154...Systems § 154.405 Design vapor pressure (Po ) of a cargo tank. (a) The design vapor pressure (Po ) of a cargo tank must be equal to or...

2009-10-01

139

46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405 Section 154...Systems § 154.405 Design vapor pressure (Po ) of a cargo tank. (a) The design vapor pressure (Po ) of a cargo tank must be equal to or...

2010-10-01

140

A Comparison of Saturation Pressure Differences and GOES VAS Estimates to Surface Observations of Cloudiness.  

NASA Astrophysics Data System (ADS)

Saturation pressure differences, a measure of parcel saturation, are calculated from upper-air soundings and compared to manual surface observations of cloudiness. The saturation pressure level p( (more commonly referred to as the lifted condensation level, LCL), can be calculated for each level in a sounding using the temperature and dewpoint temperatures. Thus, p( of an unsaturated air parcel is found by dry-adiabatic ascent to the pressure level where the parcel is just saturated. The difference between air parcel pressure and saturation pressure level defines the parcel saturation pressure difference. The mean saturation pressure difference between 1000 and 700, 700 and 400, and 400 and 300 mb is calculated and compared to the observed composite cloudiness for those layers. Results indicate that as the absolute value of saturation pressure difference decreases toward zero, the resulting ground observed composite cloud amount increases. However, the mean saturation pressure difference for high clouds ranges from 64 mb under clear skies to 16 mb for overcast conditions. This corresponds to relative humidities between 25% and 76%. Most previous studies do not indicate such large cloud amounts at these humidities. Three empirical relationships that define low, middle, and high clouds are developed based on one year of comparisons. These relationships are then tested on an independent dataset that include a wide variety of cloud cover conditions. Qualitative comparisons are made to manual observations of cloudiness and indicate that the relationships overall slightly overestimate the frequency of cloudiness. Cloudiness derived from the Visible-Infrared Spin Scan Radiometer (VISSR) Atmospheric Sounder (VAS) onboard the Geostationary Environmental Operational Satellite (GOES) 7 using the CO2 slicing technique is also compared to surface observations. Results indicate that the satellite-derived cloudiness overestimates cloudiness compared with surface observations but is also very similar to the saturation pressure difference estimates.

Alliss, Randall J.; Raman, Sethu

1996-04-01

141

Strain localisation modelling and pore pressure in saturated sand samples  

Microsoft Academic Search

Dynamic strain localisation theory together with a multiphase material model is used to simulate shear band dominated processes\\u000a in fully saturated sand samples. The fluid-saturated medium is viewed as multi-phase continuum consisting of a solid skeleton\\u000a and pores filled by fluids. The governing equations are based on the general framework of averaging theories. A generalised\\u000a plasticity constitutive model for fully

B. A. Schrefler; H. W. Zhang; M. Pastor; O. C. Zienkiewicz

1998-01-01

142

Vapor pressure ratios over the solid neon isotopes  

Microsoft Academic Search

The first data for the neon-21 to neon-22 isotopic vapor pressure ratio are presented. New data of improved precision are presented for the neon-20 to neon-22 ratio. The use of the two sets of data narrows considerably the allowable temperature-dependent form of the free energy expansion in powers ofh2\\/2m required to describe the data. The effective Debye temperature determined in

G. T. McConville

1974-01-01

143

Vapor pressure ratios over the solid neon isotopes  

Microsoft Academic Search

The first data for the neon-21 to neon-22 isotopic vapor pressure ratio are presented. New data of improved precision are presented for the neon-20 to neon-22 ratio. The use of the two sets of data narrows considerably the allowable temperature-dependent form of the free energy expansion in powers of h 2\\/2 m required to describe the data. The effective Debye

G. T. McConville

1974-01-01

144

Vapor-Phase Thermal Conductivity, Vapor Pressure, and Liquid Density of R365mfc  

Microsoft Academic Search

The thermal conductivity of a new fluoroalkane, R365mfc (1,1,1,3,3-pentafluorobutane), important for the production of polyurethane rigid foams, was measured using a transient hot wire method, at temp- eratures between 336.85 K and 377.4 K. The extended corresponding states theory was used successfully to predict the results, with an average absolute deviation of 0.5%. The vapor pressure (302.90 K to 358.15

Isabel M. Marrucho; Nelson S. Oliveira; Ralf Dohrn

2002-01-01

145

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, July 1 - September 31, 1996  

SciTech Connect

The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude. This project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal; (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars; and (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. During this quarter we have extended the work on measurements of vapor pressures of coal tars, using the continuous Knudsen effusion technique. These results need further analysis and therefore in this report we describe only the general idea behind the technique, and also show some typical results.

Suuberg, E.M.; Oja, V.; Lilly, W.D. [Brown Univ., Providence, RI (United States)

1996-12-31

146

Effect of relative vapor pressure on separation of nanoscale contact in atomic force microscope  

NASA Astrophysics Data System (ADS)

The separation of nanoscale contact junction is investigated in an atomic force microscope at various relative vapor pressure conditions. Gradual increase in adhesion force is observed as the relative vapor pressure increases. However, the force-deformation behaviors of the water-mediated nanoscale contacts vary extensively with the relative vapor pressure conditions. At low relative vapor pressure (p/ps<0.06), water molecules play a role as a weak glue contributing solid extension. In contrast, at high relative vapor pressure (p/ps=0.8), the highest adhesion force is observed without indication of the solid extension. The meniscus collapses and forms a water column after solids separates at an intermediate relative vapor pressure condition (p/ps=0.4). The detailed analysis revealed the transition of adhesion mechanism from the solid-dominant adhesion to liquid-dominant adhesion as the relative vapor pressure increases.

Kim, Doo-In; Jeong, Young-Keun; Kang, Myung-Chang; Ahn, Hyo-Sok; Kim, Kwang Ho

2010-12-01

147

Acoustic and mechanical response of reservoir rocks under variable saturation and effective pressure.  

PubMed

We investigate the acoustic and mechanical properties of a reservoir sandstone saturated by two immiscible hydrocarbon fluids, under different saturations and pressure conditions. The modeling of static and dynamic deformation processes in porous rocks saturated by immiscible fluids depends on many parameters such as, for instance, porosity, permeability, pore fluid, fluid saturation, fluid pressures, capillary pressure, and effective stress. We use a formulation based on an extension of Biot's theory, which allows us to compute the coefficients of the stress-strain relations and the equations of motion in terms of the properties of the single phases at the in situ conditions. The dry-rock moduli are obtained from laboratory measurements for variable confining pressures. We obtain the bulk compressibilities, the effective pressure, and the ultrasonic phase velocities and quality factors for different saturations and pore-fluid pressures ranging from normal to abnormally high values. The objective is to relate the seismic and ultrasonic velocity and attenuation to the microstructural properties and pressure conditions of the reservoir. The problem has an application in the field of seismic exploration for predicting pore-fluid pressures and saturation regimes. PMID:12703693

Ravazzoli, C L; Santos, J E; Carcione, J M

2003-04-01

148

Capillary pressure characteristics necessary for simulating DNAPL infiltration, redistribution, and immobilization in saturated porous media  

Microsoft Academic Search

This study presents a capillary-pressure saturation (PC-S) constitutive model that incorporates the capillary phenomena necessary for simulating the spatial distribution of nonwetting fluid migrating in a saturated porous medium. To develop a model validation data set, a sequence of dense, nonaqueous phase liquid (DNAPL) pools were emplaced, under alternating drainage and imbibition conditions, in a one-dimensional, 1 m tall, saturated

J. I. Gerhard; B. H. Kueper

2003-01-01

149

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric uranium dioxide at high temperatures  

SciTech Connect

Thermodynamic functions of the gaseous species, thermodynamic functions of the condensed phase, and an oxygen-potential model have been combined to calculate the vapor pressures and vapor compositions in equilibrium with condensed-phase UO/sub 2-x/ for 1500 less than or equal to T less than or equal to 6000 K and 0 less than or equal to x less than or equal to 0.5. A method for extending the oxygen-potential model of Blackburn to the liquid region has been derived and evaluated. New thermodynamic functions of the UO/sub 2/ condensed phase have been derived from the best available data, including the heat capacity recommended by Fink.

Green, D.W.; Leibowitz, L.

1981-06-01

150

Vapor-liquid equilibrium of methane-n-pentane system at low temperatures and high pressures  

Microsoft Academic Search

Rice University reports vapor-liquid equilibrium data for a methane-n-pentane system at temperatures applied in natural gas processing: 0, -25, -50, -75, -80.95, and -100°C. Measurements of the bubble-point compositions are combined with earlier dew-point data to give K-values for the system at pressures ranging from the vapor pressure of n-pentane to the critical pressure or vapor pressure of methane. The

Teh-Cheng Chu; Roger J. J. Chen; Patsy S. Chappelear; Riki Kobayashi

1976-01-01

151

Generation of high concentration aerosols from low vapor pressure compounds  

SciTech Connect

A generation system has been developed and used to produce exposure atmospheres containing respirable aerosols at high concentration (up to 5 mg of test compound per liter in air) from high boiling point, low vapor pressure compounds. Nine compounds were evaluated to demonstrate the effectiveness of the generation system. In each test at least 84% of the particles were in the respirable range (particle size 10 ..mu..m or less) with a mass median aerodynamic diameter of less than 3.2 ..mu..m. The system is easy to operate, reliable, versatile, provides reproducible results and is relatively inexpensive to construct.

Blank, T.L.; Velasquez, D.J.; Bechtel, C.L.; Roloff, M.V.

1987-10-01

152

Vapor pressure isotope effect in liquid methylene fluoride  

Microsoft Academic Search

The vapor pressures of the isotopic methylene fluorides ¹²CHF, ¹²CDF and ¹³CHF have been measured at temperatures between 149 and 244°K by differential manometric techniques in a precision cryostat. Over the entire temperature range of the measurements, P(¹²CHF) > P(¹²CDF) and P(¹²CHF) < P(¹³CHF). The data are best represented by T 1n(f\\/sub c\\/\\/f\\/sub g\\/) = (632.26 +- 97.62)\\/T + (19.175

A. Kanungo; T. Ishida

1986-01-01

153

Vapor pressure isotope effects in liquid methyl fluoride  

Microsoft Academic Search

The vapor pressures of the isotopic methyl fluorides ¹²CHF, ¹²CDF, and ¹³CHF have been measured at temperatures between 132.48 and 213.12 K by differential manometric techniques in a precision cryostat. Throughout the whole temperature range of the measurements, P(¹²CHF) > P(¹²CDF) and P(¹²CHF) < P(¹³CHF). The data are best represented by T ln (f\\/sub c\\/\\/f\\/sub g\\/) = (2225.2 +- 7.4)\\/T

Takao Oi; Jan Shulman; Anthony Popowicz; Takanobu Ishida

1983-01-01

154

Ignitability of DMSO vapors at elevated temperature and reduced pressure  

SciTech Connect

Ignitability of DMSO vapors have been evaluated at 664 mm Hg pressure. The minimum temperature at which the DMSO vapors that are in equilibrium with liquid DMSO has been determined using two types of strong ignition sources. This temperature is 172 F for chemical igniters, and 178 F for spark ignition. Numerous tests have been conducted using controlled intensity sparks to define the shape of the minimum ignition energy curve as a function of temperature. The ignition energies spanned four orders of magnitude (approximately from 20,000 to 2 mJ) while the DMSO vapor mixture temperature varied from 185 to 207 F. The Sandia Generator was used to simulate worst case electrostatic sparks that can be produced by the human body. Although it was not designed for air discharges, this device had been used by LLNL for 1 mm spark gap and the resultant spark energy had been measured to fall within the range from 3.2 to 8.8 mJ. CRC tests using this device showed that the minimum ignition temperature strongly depends on the spark gap. The minimum ignition temperature was 207 F at 1 mm spark gap, 203 F at 3 mm spark gap, and 197 F at 6 mm spark gap. This strong dependence on the spark gap is believed to be partly due to the changes in the spark energy as the spark gap changes.

Bergman, W; Ural, E A; Weisgerber, W

1999-03-08

155

Reappraisal of disparities between osmolality estimates by freezing point depression and vapor pressure deficit methods  

Microsoft Academic Search

As a response to recent expression of concern about possible unreliability of vapor pressure deficit measurements (K. Kiyosawa, Biophys. Chem. 104 (2003) 171188), the results of published studies on the temperature dependence of the osmotic pressure of aqueous polyethylene glycol solutions are shown to account for the observed discrepancies between osmolality estimates obtained by freezing point depression and vapor pressure

Donald J. Winzor

2004-01-01

156

Bubble-point pressures and saturated- and compressed-liquid densities of the binary R-125 + R-143a system  

SciTech Connect

Bubble-point pressures and saturated- and compressed-liquid densities of the binary R-125 (pentafluoroethane) + R-143a (1,1,1-trifluoroethane) system have been measured for several compositions at temperatures from 280 to 330 K by means of a magnetic densimeter coupled with a variable-volume cell mounted with a metallic bellows. The experimental uncertainties of the temperature, pressure, density, and composition were estimated to be within {+-}10 mK, {+-}12 kPa, {+-}0.2%, and {+-}0.2 mass %, respectively. The purities of the samples used throughout the measurements are 99.96 area % for R-125 and 99.94 area % for R-143a. Based on these measurements, the thermodynamic behavior of the vapor-liquid equilibria of this binary refrigerant mixture has been represented using the Peng-Robinson equation for the bubble-point pressures, a correlation for the saturated-liquid densities, and an equation of state for the compressed-liquid densities.

Fujimine, T.; Sato, H.; Watanabe, K.

1999-05-01

157

Effect of cationic surfactants on organic liquid-water capillary pressure-saturation relationships  

Microsoft Academic Search

Many solutes, either naturally occurring or introduced, are surface active and sorb preferentially at the interfaces of subsurface systems. In multiphase systems, the sorption of surfactants affects the capillary pressure-saturation relationships, fundamental constitutive relationships in the modeling of multiphase flow. In this study, the impact of surfactant sorption on capillary pressure relationships for organic liquid-waters systems was demonstrated by qualitatively

A. H. Demond; K. F. Hayes; F. N. Desai

1994-01-01

158

Pressure, flow and oxygen saturation sensors on one chip for use in catheters  

Microsoft Academic Search

This paper presents a combination sensor chip, which is to be fitted to a catheter for use in intervention therapy. The chip contains an absolute pressure sensor, a thermal flow sensor and a colour sensor to determine respectively: blood pressure, blood flow velocity and oxygen saturation in one location at the same time. The sensors where fabricated using epi-micromachining. Change

J. F. L. Goosen; P. J. French; P. M. Sarro

2000-01-01

159

250W diode laser for low pressure Rb vapor pumping  

NASA Astrophysics Data System (ADS)

The diode pumped alkali vapor lasers operating at subatmospheric pressure require developing of a new generation of high-power laser diode sources with about 10 GHz wide emission spectrum. The latest achievements in the technology of volume Bragg gratings (VBGs) recorded in photo-thermo-refractive glass opened new opportunities for the design and fabrication of compact external cavity laser diodes, diode bars and stacks with reflecting VBGs as output couplers. We present a diode laser system providing up to 250 W output power and emission spectral width of 20 pm (FWHM) at the wavelength of 780 nm. The stability and position of an emission wavelength is determined by the resonant wavelength of a VBG which is controlled by temperature. Stability of an emitting wavelength is within 5 pm. Thermal tuning of the wavelength provides maximum overlapping of emitting line with absorption spectrum of a Rb (rubidium)- cell. The designed system consists of 7 modules tuned to the same wavelength corresponding to D2 spectral line of Rb87 or Rb85 and coupled to a single output fiber. Analogous systems could be used for other Rb isotopes spectral lines as well as for lasers based on other alkali metal vapors (Cs and K) or any agents with narrow absorption lines.

Podvyaznyy, A.; Venus, G.; Smirnov, V.; Mokhun, O.; Koulechov, V.; Hostutler, D.; Glebov, L.

2010-02-01

160

Calculations of the Equilibrium Vapor Pressure of Water over Adhering 50200-nm Spheres  

Microsoft Academic Search

Treatments of condensation on aerosols generally assume the particles to be spherical implying that the condensate presents a positively curved surface to the surrounding vapor. In contrast, the region between two adhering spheres supports a pendular ring of condensation which may result in a condensate-vapor interface with negative curvature. According to the Kelvin equation, the equilibrium vapor pressure over such

Yoan Crouzet; William H. Marlow

1995-01-01

161

Simplified Calculation of CACO3 Saturation at High Temperatures and Pressures in Brine Solutions  

Microsoft Academic Search

A simplified method to calculate CaCtheta saturation is developed using only commonly measured field parameters. The calculated saturation index, l\\/sub s\\/, and pH values are accurate at high temperatures and pressures in brines and are compared with less sophisticated and more complex calculations. The final forms of l\\/sub s\\/ and pH calculations are derived using conditional equilibrium constants dependent on

John Oddo; Mason Tomson

1982-01-01

162

High-pressure density and vaporliquid equilibrium for the binary systems carbon dioxideethanol, carbon dioxideacetone and carbon dioxidedichloromethane  

Microsoft Academic Search

An apparatus for the measurement of vaporliquid equilibrium (VLE, PTx) data and density of saturated-liquid and high-pressure liquid phase of compressed gas-organic solvent systems was designed, built and tested. A synthetic method, with recirculation of the liquid phase through a high-pressure densimeter by a magnetic driven centrifugal pump, was used. The thermodynamic equilibrium was reached in a visual cell with

Matteo Stievano; Nicola Elvassore

2005-01-01

163

Effects of heterogeneities on capillary pressure-saturation-relative permeability relationships.  

PubMed

In theories of multiphase flow through porous media, capillary pressure-saturation and relative permeability-saturation curves are assumed to be intrinsic properties of the medium. Moreover, relative permeability is assumed to be a scalar property. However, numerous theoretical and experimental works have shown that these basic assumptions may not be valid. For example, relative permeability is known to be affected by the flow velocity (or pressure gradient) at which the measurements are carried out. In this article, it is suggested that the nonuniqueness of capillary pressure-relative permeability-saturation relationships is due to the presence of microheterogeneities within a laboratory sample. In order to investigate this hypothesis, a large number of "numerical experiments" are carried out. A numerical multiphase flow model is used to simulate the procedures that are commonly used in the laboratory for the measurement of capillary pressure and relative permeability curves. The dimensions of the simulation domain are similar to those of a typical laboratory sample (a few centimeters in each direction). Various combinations of boundary conditions and soil heterogeneity are simulated and average capillary pressure, saturation, and relative permeability for the "soil sample" are obtained. It is found that the irreducible water saturation is a function of the capillary number; the smaller the capillary number, the larger the irreducible water saturation. Both drainage and imbibition capillary pressure curves are found to be strongly affected by heterogeneities and boundary conditions. Relative permeability is also found to be affected by the boundary conditions; this is especially true about the nonaqueous phase permeability. Our results reveal that there is much need for laboratory experiments aimed at investigating the interplay of boundary conditions and microheterogeneities and their effect on capillary pressure and relative permeability. PMID:12102317

Ataie-Ashtiani, Behzad; Hassanizadeh, S Majid; Celia, Michael A

2002-06-01

164

Velocity-dependent capillary pressure in theory for variably-saturated liquid infiltration into porous media  

NASA Astrophysics Data System (ADS)

Standard theory for liquid infiltration into porous media cannot explain saturation overshoot at an infiltration front. Based on a recent generalization of the Green-Ampt approach, a new theory for variably-saturated flow is presented that assumes that capillary pressure does not only depend on liquid content but also on the flow velocity. The Eulerian expression for the nonequilibrium capillary pressure is rotationally invariant and attempts to capture the conjecture that dynamic effects are more pronounced if flow is associated with moving fluid-fluid interfaces which cause a dynamic contact angle. The new theory correctly predicts how overshoot depends on the downstream and upstream liquid contents as well as on grain size. The theory also yields the hydrostatic pressure distribution in the liquid and allows for liquid contents exceeding the saturated liquid content of the main imbibition curve that may occur for overshoot.

Hilpert, Markus

2012-03-01

165

40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standards: Pressure relief devices in gas/vapor...PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.111 Standards: Pressure relief devices in...

2013-07-01

166

40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Standards: Pressure relief devices in gas/vapor...PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.111 Standards: Pressure relief devices in...

2011-07-01

167

High pressure vapor-liquid and vapor-liquid-liquid equilibria for systems containing supercritical carbon dioxide, water and furfural  

Microsoft Academic Search

We measured vapor-liquid equilibrium for a binary system CO2?furfural at temperatures of 303 and 323 K and vapor-liquid-liquid equilibrium for a ternary system CO2?water?furfural at temperatures of 303, 323 and 343 K and pressure of 5 MPa to obtain fundamental data for concentration of furfural by using three phase separation technique. Furthermore the experimental data were compared with results calculated

Takeshi Sako; Tsutomu Sugeta; Noriaki Nakazawa; Katsuto Otake; Masahito Sato; Katsuo Ishihara; Masahiro Kato

1995-01-01

168

Vapor pressures in the ternary system water-nitric acid-sulfuric acid and low temperatures  

Microsoft Academic Search

The partial vapor pressures over liquid or supercooled solutions of water and nitric acid and of water and sulfuric acid are calculated for temperatures below 0 C. From these results, the partial vapor pressures over the tenary system water-nitric acid-sulfuric acid (liquid or supercooled) have been estimated and compared with the available experimental data of Vandoni (1944) at 0 C.

A. Jaecker-Voirol; J. L. Ponche; P. Mirabel

1990-01-01

169

The Determination of Vapor Pressures of Low Viscosity Lubricants from Distillation Data  

Microsoft Academic Search

The vapor pressure of low viscosity aliphatic hydrocarbon lubricants is shown to be determined with good accuracy from data obtained from a modification of the ASTM Distillation Test D86-67. This test gives the initial boiling point of a lubricant from which the vapor pressure at any other temperature can be calculated by use of an empirical equation relating the boiling

W. G. Johnston; L. B. Sargent Jr

1970-01-01

170

Thermogravimetric determination of vapor pressure of diffusion pump oils by Knudsen effusion cell technique  

Microsoft Academic Search

A procedure has been developed for the determination of vapor pressure of diffusion pump oils using a Knudsen effusion cell in conjunction with a vacuum balance. The extrapolated vapor pressure of the diffusion pump oils evaluated ranged from 4 x 10⁻⁸ to 2 x 10⁻⁶ torr at 20°C.

Steckel

1980-01-01

171

Method and apparatus to measure vapor pressure in a flow system  

DOEpatents

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.

Grossman, M.W.; Biblarz, O.

1991-10-15

172

40 CFR 63.1030 - Pressure relief devices in gas and vapor service standards.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Pressure relief devices in gas and vapor service...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL...Level 2 Standards § 63.1030 Pressure relief devices in gas and vapor...

2013-07-01

173

40 CFR 63.1011 - Pressure relief devices in gas and vapor service standards.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Pressure relief devices in gas and vapor service...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL...Leaks-Control Level 1 § 63.1011 Pressure relief devices in gas and vapor...

2013-07-01

174

Cloudiness and Its Relationship to Saturation Pressure Differences during a Developing East Coast Winter Storm.  

NASA Astrophysics Data System (ADS)

Cloudiness derived from surface observations and the Geostationary Operational Environmental Satellite VISSR (Visible Infrared Spin Scan Radiometer) Atmospheric Sounder (VAS) are compared with thermodynamic properties derived from upper-air soundings over the Gulf Stream locale during a developing winter storm. The Gulf Stream locale covers the United States mid-Atlantic coastal states, the Gulf Stream, and portions of the Sargasso Sea. Cloudiness is found quite frequently in this region. Cloud-top pressures are derived from VAS using the CO2 slicing technique and a simple threshold procedure. Cloud-base heights and cloud fractions are obtained from National Weather Service hourly reporting stations. The saturation pressure differences, defined as the difference between air parcel pressure and saturation-level pressure (lifted condensation level), are derived from upper-air soundings. Collocated comparisons with VAS and surface observations are also made. Results indicate that cloudiness is observed nearly all of the time during the 6-day period, well above the 8-yr mean. High, middle, and low opaque cloudiness are found approximately equally. Furthermore, of the high- and midlevel cloudiness observed, a considerable amount is determined to be semitransparent to terrestrial radiation. Comparisons of satellite-inferred cloudiness with surface observations indicate that the satellite can complement surface observations of cloud cover, particularly above 700 mb.Surface-observed cloudiness is segregated according to a composite cloud fraction and compared to the mean saturation pressure difference for a 1000 600-mb layer. The analysis suggests that this conserved variable may be a good indicator for estimating cloud fraction. Large negative values of saturation pressure difference correlate highly with clear skies, while those approaching zero correlate with overcast conditions. Scattered and broken cloud fractions are associated with increasing values of the saturation pressure difference. Furthermore, cloud fractions observed in this study are considerably higher than those reported in similar studies and by other cloud fraction formulations.

Alliss, Randall J.; Raman, Sethu

1995-11-01

175

Comparison of average and point capillary pressure-saturation functions determined by steady-state centrifugation  

SciTech Connect

The capillary pressure-saturation function can be determined from centrifuge drainage experiments. In soil physics, the data resulting from such experiments are usually analyzed by the 'averaging method.' In this approach, average relative saturation, , is expressed as a function of average capillary pressure, <{psi}>, i.e., (<{psi}>). In contrast, the capillary pressure-saturation function at a physical point, i.e., S({psi}), has been extracted from similar experiments in petrophysics using the 'integral method.' The purpose of this study was to introduce the integral method applied to centrifuge experiments to a soil physics audience and to compare S({psi}) and (<{psi}>) functions, as parameterized by the Brooks-Corey and van Genuchten equations, for 18 samples drawn from a range of porous media (i.e., Berea sandstone, glass beads, and Hanford sediments). Steady-state centrifuge experiments were performed on preconsolidated samples with a URC-628 Ultra-Rock Core centrifuge. The angular velocity and outflow data sets were then analyzed using both the averaging and integral methods. The results show that the averaging method smoothes out the drainage process, yielding less steep capillary pressure-saturation functions relative to the corresponding point-based curves. Maximum deviations in saturation between the two methods ranged from 0.08 to 0.28 and generally occurred at low suctions. These discrepancies can lead to inaccurate predictions of other hydraulic properties such as the relative permeability function. Therefore, we strongly recommend use of the integral method instead of the averaging method when determining the capillary pressure-saturation function by steady-state centrifugation. This method can be successfully implemented using either the van Genuchten or Brooks-Corey functions, although the latter provides a more physically precise description of air entry at a physical point.

Cropper, Clark [University of Tennessee, Knoxville (UTK); Perfect, Edmund [ORNL; van den Berg, Dr. Elmer [University of Tennessee, Knoxville (UTK); Mayes, Melanie [ORNL

2010-01-01

176

Effects of Average and Point Capillary Pressure-Saturation Function Parameters on Multiphase Flow Simulations  

NASA Astrophysics Data System (ADS)

Numerical models are an important tool in petroleum engineering, geoscience, and environmental applications, e.g. feasibility evaluation and prediction for enhanced oil recovery, enhanced geothermal systems, geological carbon storage, and remediation of contaminated sites. Knowledge of capillary pressure-saturation functions is essential in such applications for simulating multiphase fluid flow and chemical transport in variably-saturated rocks and soils in the subsurface. Parameters from average capillary pressure-saturation functions are sometimes employed due to their relative ease of measurement in the laboratory. However, the use of average capillary pressure-saturation function parameters instead of point capillary pressure-saturation function parameters for numerical simulations of flow and transport can result in significant errors, especially in the case of coarse-grained sediments and fractured rocks. Such erroneous predications can impose great risks and challenges to decision-making. In this paper we present a comparison of simulation results based on average and point estimates of van Genuchten model parameters (Sr, ?, and n) for Berea sandstone, packed glass beads, and Hanford sediments. The capillary pressure-saturation functions were measured using steady-state centrifugation. Average and point parameters were estimated for each sample using the averaging and integral methods, respectively. Results indicated that the Sr and ? parameters estimated using averaging and integral methods were close to a 1-to-1 correspondence, with R-squared values of 0.958 and 0.994, respectively. The n parameter, however, showed a major curvilinear deviation from the 1-to-1 line for the two estimation methods. This trend indicates that the averaging method systematically underestimates the n parameter relative to the point-based estimates of the integral method leading to an over predication of the breadth of the pore size distribution. Forward numerical simulations using STOMP will be employed to illustrate the magnitudes of the errors in flow and transport predictions resulting from the use of average instead of point hydraulic parameters.

Cheng, C.; Perfect, E.; Cropper, C.

2011-12-01

177

Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion  

NASA Astrophysics Data System (ADS)

Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse oximeters showed gradual decrease of saturations during induced hypoperfusion which demonstrate the direct relation between blood volumes (PPG amplitudes), arterial vessel stenosis and blood oxygen saturation. The custom made pulse oximeter was found to be more sensitive to SpO2 changes than the commercial pulse oximeter especially at high occluding pressures.

Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

2007-10-01

178

Cathode sputtering with electrical discharge through a heavy water-saturated vapor interface  

Microsoft Academic Search

An experimental study of electrical discharge in an atmosphere of heavy-water vapor was conducted. The heavy-water surface\\u000a served as the cathode. Under specific discharge conditions, intense neutron radiation induced by the discharge was observed.\\u000a The dependence of the intensity of neutron generation on the discharge current was measured.

P. P. Khramtsov; O. G. Martynenko

1996-01-01

179

Measurement and prediction of saturation-pressure relationships in three-phase porous media systems  

Microsoft Academic Search

Scaled multiphase versions of the Brooks-Corey and van Genuchten retention functions were used to describe saturation-capillary pressure curves measured in air-water, air-organic liquid and organic liquid-water systems in a sandy porous medium for four organic liquids during monotonic wetting phase drainage. Scaling was achieved by a linear transformation of capillary pressures using scaling coefficients which are shown to be closely

R. J. Lenhard; J. C. Parker

1987-01-01

180

Capillary Pressure-Saturation Relations for Saprolite: Scaling With and Without Correction for Column Height  

Microsoft Academic Search

Dense nonaqueous phase liquids (DNAPLs) are important subsur- the capillary pressure-saturation relationship, hereafter face contaminants. Information is lacking on DNAPL behavior in heterogeneous porous media such as weathered rock (saprolite). We denoted by w(hc), where w is the volumetric content of measured air-water and Fluorinert (a nontoxic DNAPL surrogate; the wetting fluid and hc is the capillary pressure head. 3M,

E. Perfect; L. D. McKay; S. C. Cropper; S. G. Driese; G. Kammerer; J. H. Dane

2004-01-01

181

Feasibility of hydroxyl concentration measurements by laser-saturated fluorescence in high-pressure flames  

Microsoft Academic Search

A feasibility study has been performed on the application of laser-saturated fluorescence (LSF) to the measurement of OH concentration in high-pressure flames. Using a numerial model for the collisional dynamics of the OH molecule under nonuniform laser excitation, we have investigated the effect of pressure on the balanced cross-rate model and determined the sensitivity of the depopulation of the laser-coupled

Campbell D. Carter; J. Thaddeus Salmon; Galen B. King; N. M. Leaurendau

1987-01-01

182

Pressure and Fluid Saturation Prediction in a Multicomponent Reservoir, using Combined Seismic and Electromagnetic Imaging.  

National Technical Information Service (NTIS)

This paper presents a method for combining seismic and electromagnetic measurements to predict changes in water saturation, pressure, and CO(sub 2) gas/oil ratio in a reservoir undergoing CO(sub 2) flood. Crosswell seismic and electromagnetic data sets ta...

G. M. Hoversten R. Gritto J. Washbourne T. Daley

2003-01-01

183

MODEL FOR HYSTERETIC CONSTITUTIVE RELATIONS GOVERNING MULTIPHASE FLOW. 1. SATURATION-PRESSURE RELATIONS  

EPA Science Inventory

In these companion papers, a general theoretical model is presented for the description of functional relationships between relative permeability k, fluid saturation S, and pressure P in two- or three-phase (e.g., air-water or air-oil-water) porous media systems subject to arbitr...

184

Effects of pressure and saturating fluid on wave velocity and attenuation in anisotropic rocks  

Microsoft Academic Search

We obtain the energy velocities and quality factors of anisotropic reservoir rocks as a function of pore pressure, partial saturation and frequency. The model is based on Biot's poroelastic theory for anisotropic media. The directional dependence of attenuation is obtained by generalizing the eigenstiffnesses of the undrained medium to relaxation functions (six at most, depending on the material symmetry). The

J. M. Carcione; K. Helbig; H. B. Helle

2003-01-01

185

Laboratory measurement of capillary pressure-saturation relationships in a rock fracture  

Microsoft Academic Search

A laboratory technique has been developed to measure the hysteretic relationship between capillary pressure and fluid saturation for a rough-walled rock fracture under different states of normal stress. The technique incorporates a loading system and a uniquely designed capillary barrier to the nonwetting phase which allows for fracture closure and provides excellent hydraulic connection of the wetting phase in the

Stanley Reitsma; Bernard H. Kueper

1994-01-01

186

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, July 1--September 30, 1995  

SciTech Connect

There is significant current interest in general area of coal pyrolysis, particularly because of the central role of pyrolysis in all thermally driven coal conversion processes-gasification, combustion, liquefaction, mild gasification, or thermal beneficiation. There remain several key data needs in these application areas. Among them is a need for more reliable correlation for prediction of vapor pressure of heavy, primary coal tars. The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to extending the work on measurements of vapor pressures of tars. For this purpose, cellulose tar and cellulose tar related compounds have been selected as model systems. Cellulose tar has a much narrower distribution of molecular weight than does coal tar, and it is much more homogeneous. Thus it is better to develop the methods to be used for coal tars on this simpler model system first.

Suuberg, E.M.

1995-12-31

187

Chemically enhanced mixed region vapor stripping of TCE-contaminated saturated peat and silty clay soils  

SciTech Connect

The objective of this study was to conduct further testing of MRVS, chemically enhanced with calcium oxide conditioning, on field- contaminated soils collected from beneath the NASA Michoud Rinsewater Impoundment. In this study, residual soil VOC levels as a function of vapor stripping time were measured to quantify VOC removal rates. Physical and chemical soil parameters expected to affect MRVS efficiency were measures. The effects of varying the calcium oxide loadings as well as varying the vapor stripping flow rates on VOC removal were also evaluated. The results of this study will be used to determine whether acceptable removals can be achieved within reasonable treatment times, remediation costs being directly proportional to the latter. The purpose of this report is to document the experimental results of this study, as well as to address issues that were raised after completion of the previous Michoud treatability work.

West, O.R.; Cameron, P.A.; Lucero, A.J.; Koran, L.J. Jr.

1996-01-01

188

Phase Behavior and Vapor Pressures of the Pyrene + 9,10-Dibromoanthracene System  

PubMed Central

The present work concerns the thermochemical and vapor pressure behavior of the pyrene + 9,10-dibromoanthracene system. The phase diagram of the system has been studied using the thaw melt method and the results show the formation of non-eutectic multiphase mixtures. The temperatures of crystallization, and enthalpies of fusion and crystallization of the system were determined by differential scanning calorimetry. The system behavior can be divided into 5 regions. The X-ray diffraction results also indicated the existence of multiple phase characteristics. The solid-vapor equilibrium studies showed that for mixtures with high mole fractions of pyrene, two different preferred states exist that determine the vapor pressure. For those mixtures with moderate and low mole fractions of pyrene, only one preferred state exists that determines vapor pressure behavior. It was also demonstrated that the vapor pressure of the mixtures is independent of the mixture preparation technique.

Fu, Jinxia; Rice, James W.; Suuberg, Eric M.

2010-01-01

189

Sodium vapor flow regimes and pressure losses on cathode side of multitube AMTEC cell  

NASA Astrophysics Data System (ADS)

A model was developed to calculate the vapor pressure losses and characterize the vapor flow regimes on the cathode side of multitube vapor-anode AMTEC cells, with internal chevrons radiation shields and TiN electrodes. Results showed that the vapor flow on the cathode side of the AMTEC cells was typically in the transition regime, and that the pressure losses due to the chevrons shield constituted about 50% of the total pressure loss. Such an increase in the vapor pressure losses, however, decreased the cell electrical power output by only about 5%, because the concentration losses in the cell were small compared to the charge-exchange polarization and internal ohmic losses.

Tournier, Jean-Michel; El-Genk, Mohamed S.

1998-01-01

190

Vapor Pressure Studies of the Solubilization of Hydrocarbons by Surfactant Micelles. Final Report, April 1, 1984-December 31, 1984.  

National Technical Information Service (NTIS)

This final report describes vapor pressure studies of the solubilization of hydrocarbons and hydrocarbon derivatives by aqueous micellar solutions. An automated vapor pressure apparatus and a manual apparatus incorporating a mercury-covered sintered-glass...

E. E. Tucker S. D. Christian

1985-01-01

191

Reducing deuterium-tritium ice roughness by electrical heating of the saturated vapor  

SciTech Connect

High gain targets for inertial confinement fusion (ICF) contain a layer of deuterium-tritium (DT) ice which surrounds a volume of DT gas in thermal equilibrium with the solid. The roughness of the cryogenic fuel layer inside of ICF targets is one of the sources of imperfections which cause implosions to deviate from perfect one dimensional performance. Experiments at Lawrence Livermore National Laboratory have shown that applying a heat flux across the inner surface of a hydrogen layer such as that inside an ICF target reduces the intrinsic roughness of the surface. We have developed a technique to generate this heat flux by applying and electric field to the DT vapor in the center of these shells. This vapor has a small but significant conductivity due to ionization caused by beta decay of tritium in the vapor and the solid. We describe here experiments using a 1.15 GHz cavity to apply an electric field to frozen DT inside of a sapphire test cell. The cell and cavity geometry allows visual observation of the frozen layers.

Mapoles, E.R. [Lawrence Livermore National Lab., CA (United States); Sater, J.D.; Monsler, E. [Schafer (W.J.) Associates, Inc., Livermore, CA (United States); Pipes, J. [Allied-Signal Inc., Livermore, CA (United States)

1996-06-14

192

Rapid measurements of boiling point and vapor pressure of short-chain triglycerides by thermogravimetric analysis  

Microsoft Academic Search

Temperature dependence of vapor pressure and the boiling points for tricaproin (Tcap) and tricaprylin (Tcpy) were measured\\u000a by a new rapid thermogravimetric analysis (TGA) method. Results were in agreement with data from other references. The Clausius\\/Clapeyron\\u000a model fitted Tcap and Tcpy vapor pressure data with errors of 6% or less for pressures ranging from ambient down to 20 mmHg.\\u000a This

J. W. Goodrum

1997-01-01

193

Comparison of height-averaged and point-measured capillary pressure-saturation relations for sands using a modified Tempe cell  

Microsoft Academic Search

Tempe cells and similar devices are often used for measurements of capillary pressure versus saturation relationships (retention curves) of soils. Average water saturation within the sample is often used as the representative saturation. For cases where the saturation distribution along the cell height is nonuniform, use of the height-averaged water saturation artificially smoothes the retention curve when the capillary pressure

Toshihiro Sakaki; Tissa H. Illangasekare

2007-01-01

194

Comparison of height-averaged and point-measured capillary pressuresaturation relations for sands using a modified Tempe cell  

Microsoft Academic Search

Tempe cells and similar devices are often used for measurements of capillary pressure versus saturation relationships (retention curves) of soils. Average water saturation within the sample is often used as the representative saturation. For cases where the saturation distribution along the cell height is nonuniform, use of the height-averaged water saturation artificially smoothes the retention curve when the capillary pressure

Toshihiro Sakaki; Tissa H. Illangasekare

2007-01-01

195

Vaporliquid equilibrium, densities and viscosities for the binary system exo- and endo-tetrahydrodicyclopentadiene and pure component vapor pressures  

Microsoft Academic Search

Vapor pressures of exo- and endo-tetrahydrodicyclopentadiene (THDCPD) were measured by using dynamic glass still at T=335463K. The experimental vapor pressures were fitted well with the Antoine equation. Isobaric vaporliquid equilibria for the binary system exo-THDCPD+endo-THDCPD were determined by a using dynamic method at six constant pressures of 10, 30, 50, 70, 90 and 101.3kPa. All the VLE data sets were

Kyu-Jin Han; In-Chan Hwang; So-Jin Park; Myung-Jae Choi; Sang-Bong Lee; Jeong-Sik Han

2006-01-01

196

Influence of viscous fingering on dynamic saturation-pressure curves in porous media  

NASA Astrophysics Data System (ADS)

We study drainage-imbibition experiments on quasi-two-dimensional porous models. The models are transparent, allowing the displacement process and structure to be monitored in space and time. Results obtained in the case of quasi-static drainage cycles are compared to standard water retention experiments. We show that the so-called dynamic effects referred in the literature of experimentally measured capillary pressure curves might be explained by the combined effect of capillary pressure along the invasion front of the gaseous phase and pressure changes caused by viscous effects. A detailed study of the structure optically followed shows that the geometry of the invader is self-similar with two different behaviors at small and large scales: the structure corresponds to the ones of invasion percolation models at small scales (capillary fingering structures with fractal dimension D=1.83), whereas at large scales, viscous pressure drops dominate over the capillary threshold variations, and the structures are self-similar fingering structures with a fractal dimension corresponding to Dielectric Breakdown Models (variants of the DLA model), with D??1.5. The cross-over scale is set by the scale at which capillary fluctuations are of the order of the viscous pressure drops. This leads physically to the fact that cross-over scale between the two fingering dimensions, goes like the inverse of the capillary number. This study utilizes these geometrical characteristics of the viscous fingers forming in dynamic drainage, to obtain a meaningfull scaling law for the saturation-pressure curve at finite speed, i.e. the so-called dynamic capillary pressure relations. We thus show how the micromechanical interplay between viscous and capillary forces leads to some pattern formation, which results in a general form of dynamic capillary pressure relations. By combining these detailed informations on the displacement structure with global measures of pressure, saturation and controlling the capillary number Ca, a scaling relation relating pressure, saturation, system size and capillary number is developed. By applying this scaling relation, pressure-saturation curves for a wide range of capillary numbers can be collapsed.

Lvoll, G.; Toussaint, R.; Mly, K. J.; Schaefer, G.; Schmittbuhl, J.; Jankov, M.; Mheust, Y.

2009-04-01

197

Atmospheric Pressure Chemical Vapor Deposition of Titanium Nitride  

NASA Astrophysics Data System (ADS)

Titanium nitride (TiN) is a technologically important material due to its chemical inertness, high melting point, hardness, and electrical and optical properties. The low resistivity and chemical inertness make TiN the material of choice for diffusion barriers in microelectronic applications. Thin films (<800A) of TiN were grown by Atmospheric Pressure Chemical Vapor Deposition (APCVD) from tetrakis(dimethylamido) titanium (TDMAT) or tetrakis(diethylamido) titanium (TDEAT) with and without ammonia. Depositions were conducted under cold wall reactor and laminar flow conditions in a belt furnace at low temperatures (190^circ C-420^circC). Films were characterized by four point probe, Rutherford Backscattering, Forward Recoil, and X-Ray Photoelectron Spectroscopies. Films grown from TDMAT and TDEAT in the absence of ammonia were substoichiometric (N/Ti < 0.76), highly resistive (rho > 2.2 times 10^4 muOmega-cm), and contained carbon (C/Ti = 0.15-0.45), oxygen (O/Ti = 0.7-1.3), and hydrogen. TDMAT was more reactive than TDEAT, depositing films at lower temperatures and lower ammonia concentrations. TiN deposition rates ranged from 10A/min (280^ circ, TDEAT) to 190A/min (420^ circC, TDMAT) in the absence of ammonia. Film stoichiometries improved dramatically with the addition of ammonia (NH_3/TDMAT >=q 1; NH_3/TDEAT >=q 4). N/Ti ranged from 0.9-1.1, increasing with the ammonia concentration. Oxygen and carbon concentrations fell to 0.5 and <0.1 respectively, relative to the titanium content. Nitrogen, oxygen, and carbon concentrations were insensitive to temperature when ammonia was coreacted with the metal precursor. Hydrogen concentration continued to fall with increasing ammonia partial pressure. Film growth rates (220-300 A/min) were only weakly dependent on temperature or ammonia concentration, except for TDMAT at 420^circC. Ammonia reduced the film growth rate at these conditions. Lowest resistivities were obtained at 370^circ under high ammonia concentrations (NH_3 /TDMAT = 26, rho = 1500 muOmega-cm; NH_3/TDEAT = 110, rho = 660 mu Omega-cm). Though less reactive, TDEAT had a higher conversion rate of titanium atoms (gas phase)/titanium atoms (deposited film) of 35% than TDMAT (10%), probably due to excessive dust formation from TDMAT. Preliminary conformality measurements suggest that TDEAT films have better step coverage than films from TDMAT.

Musher, Joshua N.

198

The HDO/H2O relationship in tropospheric water vapor in an idealized last-saturation model  

NASA Astrophysics Data System (ADS)

Previous model studies have shown that the isotopic composition of tropospheric water vapor is sensitive to atmospheric water transport processes, but compositional information is difficult to interpret due to the complexity of the models. Here an attempt is made to clarify the sensitivity by computing the relationship between tropospheric HDO (via ?D) and H2O (via specific humidity q) in an idealized model atmosphere based on a "last-saturation" framework that includes convection coupled to a steady large-scale circulation with prescribed horizontal mixing. Multiple physical representations of convection and mixing allow key structural as well as parametric uncertainties to be explored. This model has previously been shown to reproduce the essential aspects of the humidity distribution. Variations of?D or qindividually are dominated by local dynamics, but their relationship is preserved advectively, thus revealing conditions in regions of convection. The model qualitatively agrees with satellite observations, and reproduces some parametric sensitivities seen in previous GCM experiments. Sensitivity to model assumptions is greatest in the upper troposphere, apparently because in-situ evaporation and condensation processes in convective regions are more dominant in the budget there. In general, vapor recycling analogous to that in continental interiors emerges as the crucial element in explaining why?D exceeds that predicted by a simple Rayleigh process; such recycling involves coexistent condensation sinks and convective moisture sources, induced respectively by (for example) waves and small-scale convective mixing. The relative humidity distribution is much less sensitive to such recycling.

Sherwood, S. C.; Risi, C.

2012-10-01

199

High Pressure Oxidation of 4H-SiC in Nitric Acid Vapor  

Microsoft Academic Search

High pressure chemical vapor oxidation of SiC in nitric acid vapor is reported. Higher growth rate at temperatures as low as 400 to 500 C has been achieved. The oxidation kinetics has been studied. It has been observed that the growth rate is strongly dependent on temperature, and the thickness of the oxide increases almost linearly with time within the

K. Kalai Selvi; Turuvekere Sreenidhi; Nandita DasGupta; Heiner Ryssel; Anton Bauer

2011-01-01

200

Kinetics of physical vapor transport at low pressure under microgravity conditions  

Microsoft Academic Search

An autonomously operating apparatus has been developed for the measurement of the transport rate of mercuric iodide vapor. It was flown aboard the Space Shuttle STS-77 mission in May 1996. The results of the diffusion coefficient measurement facility (DCMF) space experiment provide a breakthrough in the understanding of the transport phenomena during the physical vapor transport under low total pressures

M. Piechotka; E Kaldis; G Wetzel; H.-J Schneider; W Buff; M Tardy; H Stanna

1998-01-01

201

A new theoretical method for calculating temperature and water vapor saturation ratio in an expansion cloud chamber  

NASA Astrophysics Data System (ADS)

The expansion cloud chamber is a widely used apparatus for investigating the dynamics of condensational growth of aerosols and clouds. Theoretical calculations of temperature T and water vapor saturation ratio S are necessary for quantitative interpretations of experimental data obtained from the expansion cloud chamber. In this paper, we revisit the thermodynamics associated with the underlying assumptions for calculating the time-dependent temperature T(t) and saturation ratio S(t) in an expansion chamber as a function of experimentally observable parameters. We introduce an intuitive and robust method, the virtual path (VP) method, by which changes in the thermodynamic state of a moist air parcel containing cloud droplets are schematically represented on a thermodynamic diagram. The validity of the VP method is confirmed by comparisons with the differential equation (DE) method, which is a numerical simulation of real physical processes according to the time evolution equations involving T and S. In contrast to the conventional DE method, the governing equations of the VP method do not involve time t, an irrelevant parameter in the framework of classical thermodynamics. The VP method is advantageous compared to the DE method because the former is applicable to the raw experimental data acquired with a finite time resolution, allowing a robust calculation of the T and S values and the errors that are only caused by the measurement errors of the input data.

Moteki, Nobuhiro; Kondo, Yutaka

2013-06-01

202

Vapor Pressure of HCl - Water and Salt - HCl - Water Solutions Below OC.  

National Technical Information Service (NTIS)

Liquid solution analyses were completed. The complete vapor-liquid equilibria data are tabulated for hydrochloric acid solutions ranging in molality from 5.0 to 15.7, saturated with CaCl2 at nominal temperatures ranging from 0 to -40C. The CaCl2-HCl-water...

E. Miller

1984-01-01

203

A model for hysteretic constitutive relations governing multiphase flow: 1. Saturation-pressure relations  

NASA Astrophysics Data System (ADS)

In these companion papers, a general theoretical model is presented for the description of functional relationships between relative permeability k, fluid saturation S, and pressure P in two-or three-phase (e.g., air-water or air-oil-water) porous media systems subject to arbitrary saturation paths. A parametric description of hysteretic S-P relations is developed in paper 1 which includes effects of air and oil phase occlusion or "entrapment" during imbibition. Entrapped nonwetting fluid saturations at a given point along a saturation path are linearly interpolated between endpoints of primary imbibition scanning curves using maximum trapped saturations estimated by extension of the method of Land (1968). Arbitrary order scanning curves are predicted using an empirical interpolation scheme coupled with a scaling procedure which simplifies computations and minimizes the parametric complexity of the model. All model parameters are defined in terms of measurements which may be obtained from two-phase systems (air-water, air-oil, oil-water). Extension to three-phase systems is based on the assumption that fluid entrapment processes in three phase systems are similar to those in two-phase systems and that wettability decreases in the order: water to oil to air.

Parker, J. C.; Lenhard, R. J.

1987-12-01

204

Implantable Drug Dispenser: Differential vapor pressure allows fine control.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. Drugs such as insulin would be injected as needed directly into the bloodstream by a compact implantable dispensing unit. The dispenser uses counteracting vapor pres...

1983-01-01

205

Final Report for Vapor Pressure Study of Explosives and Related Compounds.  

National Technical Information Service (NTIS)

This is the final report for a program to assemble an easily used, critically reviewed database of vapor pressures over explosives. The compounds that were considered in this work included selected actual explosives, and also associated manufacturing and ...

P. E. Gongwer

2003-01-01

206

Experimental studies on the enhanced flow boiling heat transfer and pressure drop of organic fluid with high saturation temperature in vertical porous coated tube  

NASA Astrophysics Data System (ADS)

The characteristics of flow boiling heat transfer and pressure drop of organic fluid with high saturation temperature in a vertical porous coated tube are experimentally studied in this paper. The experiments are performed at evaporation pressure of 0.16-0.31MPa, mass flux of 390-790kg/m2s, and vapor quality of 0.06-0.58. The variations of heat transfer coefficient and pressure drop with vapor quality are measured and compared to the results of smooth tube. Boiling curves are generated at mass flux of 482 and 675kg/m2s. The experimental results indicate that the heat transfer coefficients of the porous tube are 1.8-3.5 times those of smooth tube, and that the frictional pressure drops of the porous tube are 1.1-2.9 times those of smooth tube. The correlations for heat transfer coefficient and frictional pressure drop are derived, in which the effect of fluid molecular weight is included. The experiments show that significant heat transfer enhancement is accompanied by a little pressure drop penalty, the application of the porous coated tube is promising in the process industries.

Yang, Dong; Shen, Zhi; Chen, Tingkuan; Zhou, Chenn Q.

2013-07-01

207

Vapour pressures of saturated aqueous solutions of ammonium iodide, potassium iodide, potassium nitrate, strontium chloride, lithium sulphate, sodium thiosulphate, magnesium nitrate, and uranyl nitrate from T =(278 to 323) K  

Microsoft Academic Search

Vapour pressures of saturated aqueous solutions of NH4I, KI, KNO3, SrCl2, Li2SO4, Na2S2O3, Mg(NO3)2, and UO2(NO3)2were determined in the temperature range (278 to 323) K using an electronic hygrometer with an electrolyte sensor, and compared with literature data. Water activities, osmotic coefficients, and molar enthalpies of vaporization and solution at saturation point were evaluated from the determined vapour pressures.

Alexander Apelblat; Eli Korin

1998-01-01

208

Fractional-calculus model for temperature and pressure waves in fluid-saturated porous rocks  

Microsoft Academic Search

We study a fractional time derivative generalization of a previous Natale-Salusti model about nonlinear temperature and pressure waves, propagating in fluid-saturated porous rocks. Their analytic solutions, i.e., solitary shock waves characterized by a sharp front, are here generalized, introducing a formalism that allows memory mechanisms. In realistic wave propagation in porous media we must take into account spatial or temporal

Roberto Garra

2011-01-01

209

Effects of pressure and saturation on seismic velocities and impedance measurements  

SciTech Connect

Two synthetic data sets were examined to study the possible methods for distinguishing the effects of changes in saturation, and changes in pore pressure, on seismic velocity and impedance measurements. The results show that the results obtained previously on the dependence of laboratory velocity data on changes in saturation carry over without change to the data in these data sets. The assumption in this case is that the only data available are the seismic velocities. This situation can arise in cross-well seismic tomography. Of more direct interest to this project is how these methods and results should change when the data are instead seismic impedance measurements. The main conclusions are that the most appropriate plotting methods for seismic impedance data in order to distinguish changes in saturation, changes in pressure, and saturation changes from pressure changes are ({rho}{mu}, {lambda}/{mu}) and ({mu}/{lambda}, {rho}{mu}{sup 2}/{lambda}). All of these plotting coordinates can be computed easily from the impedance data {rho}{nu}{sub p} and {rho}{nu}{sub s}, since {rho}{mu} = ({rho}{nu}{sub s}){sup 2}, and {rho}{lambda} = ({rho}{nu}{sub p}){sup 2} - 2({rho}{nu}{sub s}){sup 2}, while {lambda}/{mu} = {rho}{lambda}/{rho}{mu} and {rho}{mu}{sup 2}/{lambda} = ({rho}{mu}){sup 2}/{rho}{lambda}. These choices are not the only possibilities, but they seem to give the desired results in many situations. Some issues remain concerning the details at high porosities and small pore pressures, and these will need to be addressed in future work.

Berryman, J G

2001-01-18

210

Fractional wettability effects on two-and three-fluid capillary pressure-saturation relations  

Microsoft Academic Search

Studies of the relation between capillary pressure (Pc) and fluid saturation (S) for porous media containing oil-water or air-oil-water, often assume that the medium is strongly water-wet. Natural porous media, however, are composed of a variety of mineral constituents; such media are typically composed of water- and oil-wet fractions. This study reports on two- and three-fluid Pc-S data for media

Scott A. Bradford; Feike J. Leij

1995-01-01

211

A new formula for saturated water steam pressure within the temperature range ?25 to 220C  

Microsoft Academic Search

Instead of approximation formula ln(E(t)\\/E(0)) = [(a ? bt)t\\/(c + T)] commonly used at present for representing dependence of pressure of saturated streams of liquid water E upon temperature we suggested new approximation formula of greater accuracy in the form ln(E(t)\\/E(0)) = [(A ? Bt + Ct\\u000a 2)t\\/T], where t and T are temperature in C and K respectively. For

N. P. Romanov

2009-01-01

212

Liquid-vapor equilibrium under elevated pressures in the systems formed by pentanes with sulfur compounds  

SciTech Connect

The possibility of removing sulfur compounds from the pentane fraction was studied. Experimental data obtained on liquid-vapor equilibrium in the system formed by pentanes with sulfur compounds under elevated pressures is presented. Vapor-liquid equilibrium was studied with the aid of a modified Swietoslawski apparatus made of stainless steel. Experimental data on phase equilibria of binary mixtures in the system studied are presented. The compositions and boiling points of binary azeotropes at the pressures studied are also presented.

Shakirzyanov, R.G.; Telyakov, E.S.; Serafimov, L.A.

1982-10-20

213

Vapor pressures in the ternary system water-nitric acid-sulfuric acid and low temperatures  

NASA Astrophysics Data System (ADS)

The partial vapor pressures over liquid or supercooled solutions of water and nitric acid and of water and sulfuric acid are calculated for temperatures below 0 C. From these results, the partial vapor pressures over the tenary system water-nitric acid-sulfuric acid (liquid or supercooled) have been estimated and compared with the available experimental data of Vandoni (1944) at 0 C. Some possible implications for the formation of stratospheric aerosols are also discussed.

Jaecker-Voirol, A.; Ponche, J. L.; Mirabel, P.

1990-07-01

214

Vapor pressures in the ternary system water-nitric acid-sulfuric acid at low temperatures  

SciTech Connect

The partial vapor pressures over liquid or supercooled solutions of water and nitric acid and of water and sulfuric acid are calculated for temperatures below 0C. From these results the partial vapor pressures over the ternary system water-nitric acid-sulfuric (liquid or supercooled) have been estimated and compared with the available experimental data of Vandoni at 0C. Some possible implications for the formation of stratospheric aerosols are also discussed.

Jaecker-Voirol, A.; Ponche, J.L.; Mirabel, P. (Universite Louis Pasteur, Strasbourg (France))

1990-07-20

215

Thermodynamic Properties of Liquid Helium Three. Vapor Pressures below 1K  

Microsoft Academic Search

Vapor pressures of liquid He3 have been measured between 0.45 and 1.0K. Temperatures were measured by the paramagnetic susceptibility of either ferric ammonium or chrome methylamine alum. The salts were calibrated above 1K against He3 vapor pressures using the data of Abraham, Osborne, and Weinstock and the He4 temperature scales of Clement (55E) and of van Dijk and Durieux (L55).

Stephen G. Sydoriak; Thomas R. Roberts

1957-01-01

216

Observations of accelerated silicon carbide recession by oxidation at high water-vapor pressures  

Microsoft Academic Search

A study of the exposure of SiC at 1,200 C and high water-vapor pressures (1.5 atm) has shown SiC recession rates that exceed what is predicted based on parabolic oxidation at water-vapor pressures of less than or equal to 1 atm. After exposure to these conditions, distinct silica-scale structures are observed; thick, porous, nonprotective cristobalite scales form above a thin,

Karren L. More; Peter F. Tortorelli; Mattison K. Ferber; James R. Keiser

2000-01-01

217

Pressure and saturation estimation from P and S impedances: a theoretical study  

NASA Astrophysics Data System (ADS)

This work represents the first step of a study to integrate time lapse seismic and reservoir engineering data where a petro-elastic inversion from seismic data to pressure and saturation is presented. This inversion is made through an optimization procedure. In order to better understand and validate the initial step of the methodology, synthetic data (initially free of noise and errors) have been used. Through this ideal set of data, it was possible to show that pressure and saturation can be extracted from P and S impedances using only one seismic survey (3D inversion). It is also shown that this 3D approach is not robust when errors are assumed in reservoir data and it fails when, for instance, uncertainty in porosity data occurs. Thus, an improvement is made and the algorithm is rewritten based on 4D differences that diminish the wrong reservoir data effect. For both algorithms (3D and 4D), we have presented a discussion of the objective function behaviour concerning the use of P and S impedances simultaneously, the initial guess and the solution space. A sensitivity analysis discussing the influence of porosity and the dynamic properties on P and S impedances for 3D and 4D approaches is also presented. After understanding the inversion process behaviour for an ideal data set, an analysis of its results assuming different combinations of pressure and saturation variations and including some errors in the data set used is presented in the last subsections.

Davolio, Alessandra; Maschio, Clio; Jos Schiozer, Denis

2012-10-01

218

Rapid estimation of thermodynamic parameters and vapor pressures of volatile materials at nanoscale.  

PubMed

Non-isothermal measurements of thermodynamic parameters and vapor pressures of low-volatile materials are favored when time is a crucial factor to be considered, such as in the case of detection of hazardous materials. In this article, we demonstrate that optical absorbance spectroscopy can be used non-isothermally to estimate the thermodynamic properties and vapor pressures of volatile materials with good accuracy. This is the first method to determine such parameters in nanoscale in just minutes. Trinitrotoluene (TNT) is chosen because of its low melting temperature, which makes it impossible to determine its thermodynamic parameter by other rising-temperature techniques, such as thermogravimetric analysis (TGA). The well-characterized vapor pressure of benzoic acid is used to calibrate the spectrometer in order to determine the vapor pressure of low-volatile TNT. The estimated thermodynamic properties of both benzoic acid and TNT are in excellent agreement with the literature. The estimated vapor pressure of TNT is one order of magnitude larger than that determined isothermally using the same method. However, the values are still within the range reported in the literature. The data indicate the high potential for use of rising-temperature absorbance spectroscopy in determining vapor pressures of materials at nanometer scale in minutes instead of hours or days. PMID:22689500

Hikal, Walid M; Paden, Jeffrey T; Weeks, Brandon L

2012-06-11

219

The influence of surfactant sorption on capillary pressure-saturation relationships  

SciTech Connect

The capillary pressure-saturation relationship, a fundamental relationship in the description of multiphase flow, depends on the interfacial properties of the system. Sorption of a cationic surfactant such as cetyltrimethylammonium bromide (CTAB) at the various interfaces of a system changes interfacial properties such as electrophoretic mobility, interfacial tensions, and contact angle. The objective of this paper is to examine the effect of the changes in these interfacial properties on the capillary pressure-saturation relationships for the air-water-silica system. The results presented here show that as the sorption of CTAB increases, the naturally negatively-charged silica surface becomes positively charged. This change in charge is reflected in the contact angle which passes through a maximum when the electrophoretic mobility is close to zero. The spontaneous imbibition capillary pressure relationship is more sensitive to changes in interfacial properties than the drainage relationship. In the air-water-silica system studied here, no imbibition is observed at the maximum contact angle. The surface tension and contact angle can be used to predict both the drainage and imbibition relationships of the air-water-silica-CTAB systems from that of the air-water-silica system. The prediction is accomplished through scaling using the value of surface tension and the operational contact angle, which can be obtained from the intrinsic angle through the incorporation of corrections for roughness and interfacial curvature. A comparison of the measured and calculated capillary pressure relationships shows that it is possible to predict the effect of surfactant sorption on both drainage and imbibition capillary pressure-saturation relationships for the system studied.

Desai, F.N.; Demond, A.H.; Hayes, K.F.

1991-12-31

220

The influence of surfactant sorption on capillary pressure-saturation relationships  

SciTech Connect

The capillary pressure-saturation relationship, a fundamental relationship in the description of multiphase flow, depends on the interfacial properties of the system. Sorption of a cationic surfactant such as cetyltrimethylammonium bromide (CTAB) at the various interfaces of a system changes interfacial properties such as electrophoretic mobility, interfacial tensions, and contact angle. The objective of this paper is to examine the effect of the changes in these interfacial properties on the capillary pressure-saturation relationships for the air-water-silica system. The results presented here show that as the sorption of CTAB increases, the naturally negatively-charged silica surface becomes positively charged. This change in charge is reflected in the contact angle which passes through a maximum when the electrophoretic mobility is close to zero. The spontaneous imbibition capillary pressure relationship is more sensitive to changes in interfacial properties than the drainage relationship. In the air-water-silica system studied here, no imbibition is observed at the maximum contact angle. The surface tension and contact angle can be used to predict both the drainage and imbibition relationships of the air-water-silica-CTAB systems from that of the air-water-silica system. The prediction is accomplished through scaling using the value of surface tension and the operational contact angle, which can be obtained from the intrinsic angle through the incorporation of corrections for roughness and interfacial curvature. A comparison of the measured and calculated capillary pressure relationships shows that it is possible to predict the effect of surfactant sorption on both drainage and imbibition capillary pressure-saturation relationships for the system studied.

Desai, F.N.; Demond, A.H.; Hayes, K.F.

1991-01-01

221

Vapor pressures and thermal data for three high-boiling compounds of petroleum interest: 1-phenyldodecane, (5?)-cholestane, adamantane  

Microsoft Academic Search

Vapor pressures above liquid and solid phases and enthalpies of vaporization and sublimation were established in a wide temperature range for three hydrocarbons that are among the model compounds for higher boiling petroleum fractions and coal liquids. The recommended values were obtained by combining the data from vapor pressure measurements with the calorimetric measurements of heat capacities and heats of

Ilham Mokbel; Kv?toslav R?i?ka; Vladim??r Majer; Vlastimil R?i?ka; Madeleine Ribeiro; Jacques Jose; Milan Zbransk

2000-01-01

222

Pore Water Pressure Response of a Soil Subjected to Traffic Loading under Saturated and Unsaturated Conditions  

NASA Astrophysics Data System (ADS)

This study presents the results of one of the first attempts to characterize the pore water pressure response of soils subjected to traffic loading under saturated and unsaturated conditions. It is widely known that pore water pressure develops within the soil pores as a response to external stimulus. Also, it has been recognized that the development of pores water pressure contributes to the degradation of the resilient modulus of unbound materials. In the last decades several efforts have been directed to model the effect of air and water pore pressures upon resilient modulus. However, none of them consider dynamic variations in pressures but rather are based on equilibrium values corresponding to initial conditions. The measurement of this response is challenging especially in soils under unsaturated conditions. Models are needed not only to overcome testing limitations but also to understand the dynamic behavior of internal pore pressures that under critical conditions may even lead to failure. A testing program was conducted to characterize the pore water pressure response of a low plasticity fine clayey sand subjected to dynamic loading. The bulk stress, initial matric suction and dwelling time parameters were controlled and their effects were analyzed. The results were used to attempt models capable of predicting the accumulated excess pore pressure at any given time during the traffic loading and unloading phases. Important findings regarding the influence of the controlled variables challenge common beliefs. The accumulated excess pore water pressure was found to be higher for unsaturated soil specimens than for saturated soil specimens. The maximum pore water pressure always increased when the high bulk stress level was applied. Higher dwelling time was found to decelerate the accumulation of pore water pressure. In addition, it was found that the higher the dwelling time, the lower the maximum pore water pressure. It was concluded that upon further research, the proposed models may become a powerful tool not only to overcome testing limitations but also to enhance current design practices and to prevent soil failure due to excessive development of pore water pressure.

Cary, Carlos

223

Temperature and water vapor pressure effects on the friction coefficient of hydrogenated diamondlike carbon films.  

SciTech Connect

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior that does not reoccur even after extended periods of exposure to low partial pressures of H{sub 2}O and O{sub 2}. Experiments varying both water vapor pressure and sample temperature show trends of a decreasing friction coefficient as a function of both the decreasing water vapor pressure and the increasing substrate temperature. Theses trends are examined with regard to first order gas-surface interactions. Model fits give activation energies on the order of 40 kJ/mol, which is consistent with water vapor desorption.

Dickrell, P. L.; Sawyer, W. G.; Eryilmaz, O. L.; Erdemir, A.; Energy Technology; Univ. of Florida

2009-07-01

224

EVAPORISATION: a new vapor pressure model taking into account neighbour effects  

NASA Astrophysics Data System (ADS)

Secondary organic aerosol (SOA) is a complex mixture of water and organic molecules. The vapor pressure of an organic molecule is one of the most important properties regulating its partitioning to the particulate phase, but as it is unknown for most- typically polyfunctional- organic molecules in Biogenic SOA it has to be estimated by a vapor pressure model fitted to experimental data. While a lot of vapor pressure data is generally available for hydrocarbons and monofunctional compounds, much less data are available for bifunctional compounds. For compounds with more functional groups, data is sparse and relatively inaccurate. We have developed a vapor pressure model, EVAPORISATION (Estimation of VApor Pressure of ORganics, Including effects Such As The Interaction of Neighbours), starting from the group-contribution principle: each functional group gives a contribution to the logarithm of the vapor pressure. On top of that, second order effects -chemically rationalized- are added due to carbon skeleton, nonadditivity of functional groups and -for neighbouring functional groups- intramolecular interactions . These effects can be very significant: eg. when two carbonyl groups are neighbouring, the vapor pressure is about 1 order of magnitude higher than when they are nonneighbouring. Due to the lack of data, some of these effects must be estimated by analogy. The method is compared to several other vapor pressure estimation techniques, such as SIMPOL (Pankow et al. 2008), SPARC (Hilal et al. 2003), and the methods of Myrdal and Yalkowsky (1997), Capouet and Muller (2006), Nannoolal et al. (2008), Moller et al. (2008). We extended some of these methods as they are not able to treat hydroperoxides, peracids, peroxy acyl nitrates. With our model BOREAM, outlined in a previous publication (Capouet et al. 2008), several smog chamber experiments are simulated, and the impact of vapor pressure method choice is elucidated. It turns out that the choice of the vapor pressure method can have a major impact on aerosol yield, considerably larger than the choice of activity coefficient model (Compernolle et al. 2009). M. Capouet and J.-F. Muller, Atm. Chem. Phys. 6, 1455-1467 (2006) M. Capouet, J.-F. Muller, K. Ceulemans, S. Compernolle, L. Vereecken and J. Peeters, J. Geophys. Res. 113, D02308 (2008) S. Compernolle, K. Ceulemans and J. Muller, Atm. Chem. Phys. 9, 1325-1388 (2009) S.H. Hilal, S.W. Karickhoff and L.A. Carreira , QSAR Comb. Sci. 22, 565-574 (2003) P.B. Myrdal and S.H. Yalkowsky, Ind. Eng. Chem. Res. 36, 2494-2499 (1997) Y. Nannoolal, J. Rarey and D. Ramjugernath, Fluid Phase Eq. 269, 117-133 (2008) B. Moller, J. Rarey and D. Ramjugernath, J. Mol. Liq. 143, 52-63 (2008)

Compernolle, Steven; Ceulemans, Karl; Muller, Jean-Francois

2010-05-01

225

Fractional-calculus model for temperature and pressure waves in fluid-saturated porous rocks  

NASA Astrophysics Data System (ADS)

We study a fractional time derivative generalization of a previous Natale-Salusti model about nonlinear temperature and pressure waves, propagating in fluid-saturated porous rocks. Their analytic solutions, i.e., solitary shock waves characterized by a sharp front, are here generalized, introducing a formalism that allows memory mechanisms. In realistic wave propagation in porous media we must take into account spatial or temporal variability of permeability, diffusivity, and other coefficients due to the system history. Such a rock fracturing or fine particulate migration could affect the rock and its pores. We therefore take into account these phenomena by introducing a fractional time derivative to simulate a memory-conserving formalism. We also discuss this generalized model in relation to the theory of dynamic permeability and tortuosity in fluid-saturated porous media. In such a realistic model we obtain exact solutions of Burgers equation with time fractional derivatives in the inviscid case.

Garra, Roberto

2011-09-01

226

Fractional-calculus model for temperature and pressure waves in fluid-saturated porous rocks.  

PubMed

We study a fractional time derivative generalization of a previous Natale-Salusti model about nonlinear temperature and pressure waves, propagating in fluid-saturated porous rocks. Their analytic solutions, i.e., solitary shock waves characterized by a sharp front, are here generalized, introducing a formalism that allows memory mechanisms. In realistic wave propagation in porous media we must take into account spatial or temporal variability of permeability, diffusivity, and other coefficients due to the system "history." Such a rock fracturing or fine particulate migration could affect the rock and its pores. We therefore take into account these phenomena by introducing a fractional time derivative to simulate a memory-conserving formalism. We also discuss this generalized model in relation to the theory of dynamic permeability and tortuosity in fluid-saturated porous media. In such a realistic model we obtain exact solutions of Burgers' equation with time fractional derivatives in the inviscid case. PMID:22060520

Garra, Roberto

2011-09-26

227

Unified formulation of isothermal adsorbate flow in mesoporous media over the full vapor pressure range  

Microsoft Academic Search

Surface flow plays an important role in phenomena of gas or vapor transport in mesoporous pellets or membranes, which are of considerable practical interest; but a satisfactory unified formulation of surface flow over the whole applicable pressure range is as yet lacking. In analogy with gas phase flow (which varies from diffusive at low, to viscous at high, pressures), surface

J. H. Petropoulos; G. K. Papadopoulos

1995-01-01

228

Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition of Borophosphosilicate Glass Films  

Microsoft Academic Search

Borophosphosilicate glass (BPSG) films have been grown on silicon wafers by plasma enhanced chemical vapor deposition at atmospheric pressure (AP-PECVD). Tetraethoxysilane (TEOS), triethylborate (TEB), and trimethylphosphite (TMPI) were adopted as precursors, and argon and oxygen were respectively used as the carrier and reactive gases to produce stable plasma at atmospheric pressure. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS),

Minghui Yin; Lingli Zhao; Xiangyu Xu; Shouguo Wang

2008-01-01

229

Measurements of Capillary Pressure-Saturation Relationships for Silica Sands Using Light Transmission Visualization and a Rapid Pseudo Static Methods  

EPA Science Inventory

Measurement of water saturation in porous media is essential for many types of studies including subsurface water flow, subsurface colloids transport and contaminant remediation to name a few. Water saturation (S) in porous media is dependent on the capillary pressure (Pc) which,...

230

Permeabilitysaturationcapillary pressure relations in textile fabrics from an integrated upwardhorizontaldownward wicking test  

Microsoft Academic Search

A new wicking test was developed that provides intrinsic quantitative descriptors of fabrics that can be used to predict wicking behavior. These descriptors are permeability (k) and capillary pressure (Pc) as functions of saturation (S). A single fabric strip is positioned to allow sequential upward, horizontal and downward wicking of fluid from an infinite reservoir. The upward section governs saturation,

Craig B. Simile; Haskell W. Beckham

2011-01-01

231

Permeabilitysaturationcapillary pressure relations in textile fabrics from an integrated upwardhorizontaldownward wicking test  

Microsoft Academic Search

A new wicking test was developed that provides intrinsic quantitative descriptors of fabrics that can be used to predict wicking behavior. These descriptors are permeability (k) and capillary pressure (Pc) as functions of saturation (S). A single fabric strip is positioned to allow sequential upward, horizontal, and downward wicking of fluid from an infinite reservoir. The upward section governs saturation,

Craig B. Simile; Haskell W. Beckham

2012-01-01

232

Permeabilitysaturationcapillary pressure relations in textile fabrics from an integrated upwardhorizontaldownward wicking test  

Microsoft Academic Search

A new wicking test was developed that provides intrinsic quantitative descriptors of fabrics that can be used to predict wicking behavior. These descriptors are permeability (k) and capillary pressure (Pc) as functions of saturation (S). A single fabric strip is positioned to allow sequential upward, horizontal, and downward wicking of fluid from an infinite reservoir. The upward section governs saturation,

Craig B. Simile; Haskell W. Beckham

2011-01-01

233

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

PubMed

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

Kolling, William M; McPherson, Timothy B

2013-04-12

234

Parameter estimation of two-fluid capillary pressure-saturation and permeability functions  

NASA Astrophysics Data System (ADS)

Accurate characterization and modeling of subsurface flow in multi-fluid soil systems require development of a rapid, reproducible experimental method that yields the information necessary to determine the parameters of the capillary pressure-saturation and permeability functions. Previous work has demonstrated that parameter optimization using inverse modeling is a powerful approach to indirectly determine these constitutive relationships for air-water systems. We consider extension of the inverse parameter estimation method to the modified multi-step outflow method for two-fluid (air-water, air-oil and oil-water) flow systems. The wellposedness of the proposed parameter estimation problem is evaluated by its accuracy, uniqueness and parameter uncertainty. Seven different parametric models for the capillary pressure-saturation and permeability functions were tested in their ability to fit the multi-step outflow experimental data; these included the van Genuchten-Mualem (VGM) model, van Genuchten-Burdine (VGB), Brooks-Corey-Mualem (BCM), Brooks-Corey-Burdine (BCB), Brutsaert-Burdine (BRB), Gardner-Mualem (GDM) and Lognormal Distribution-Mualem (LNM) models. The VGB, BCM and BCB models fitted the multi-step outflow data poorly, and resulted in relatively large values for the root-mean-squared residuals. It was concluded that the remaining VGM, LNM, BRB and GDM models successfully characterized the multi-step experimental data for two-fluid flow systems. Although having one parameter less than the other models, the GDM model's performance was excellent. Finally, we conclude that optimized capillary pressure-saturation functions for the oil-water and air-oil could be predicted from the respective air-water function using interfacial tension ratios.

Chen, J.; Hopmans, J. W.; Grismer, M. E.

235

Investigating Dynamic Behavior in Experimental Capillary Pressure-Saturation Curves Using a Lattice-Boltzmann Model  

NASA Astrophysics Data System (ADS)

The capillary pressure-saturation curve is widely used to characterize hydraulic properties of porous media. It is often assumed that curves measured under equilibrium or steady-state flow conditions can be applied to transient flow conditions, and vice versa. Yet, substantial experimental evidence suggests that capillary pressure-saturation curves obtained during transient conditions differ from those obtained under equilibrium or steady-state conditions. It has been shown that the capillary pressure-saturation curve changes with the inflow/outflow rate applied. The exact cause of the shift is not yet fully understood, but most likely it is caused by interfacial phenomena at the pore scale. In this investigation, results from wetting/drying experiments on a column of packed glass beads under various inflow/outflow rates will be presented. The dynamic effects have been examined using conceptual 2D/3D lattice-Boltzmann (LB) simulations. The LB model used for these simulations is the multi-component model developed by Shan and Chen. The LB model is generally considered a mesoscale method, which includes pore scale properties and makes it possible to infer macroscopic dynamics from pore scale properties. The LB model also allows for representation of complex pore space geometries. These features of the LB model make it highly suitable for studying interfacial phenomena. The conceptual LB simulations provide insights into pore-scale interfacial phenomena and demonstrate the dynamic behavior observed in the experiments. The scaling of time and space from LB parameters to physical parameters was performed to make comparisons between simulation and experimental results possible.

Porter, M. L.; Wildenschild, D.; Schaap, M. G.

2005-12-01

236

Determining the saturation vapour pressures of keto-dicarboxylic acids in aqueous solutions  

NASA Astrophysics Data System (ADS)

A two-compartment binary mass transport model with group contribution methods parametrizations for the physical properties of the organic acids (UNIFAC Dortmund method for activity coefficients, GCVOL-OL-60 method for the pure liquid acid density, GC-MG method for the pure acid surface tension at room temperature, Fuller et al. method for the diffusion coefficients) was used to interpret the evaporation experiments of 100 nm sized ketodicarboxylic acid aqueous solutions droplets at ambient temperature. The determined values for the saturation vapour pressure of liquid 2-keto-glutaric acid are in the order of 10-5 Pa.

Crljenica, Ivica; Yli-Juuti, Taina; Zardini, Alessandro A.; Julin, Jan; Bilde, Merete; Riipinen, Ilona

2013-05-01

237

Pore pressure diffusion and the hydrologic response of nearly saturated, thin landslide deposits of rainfall  

SciTech Connect

Previous workers have correlated slope failures during rainstorms with rainfall intensity, rainfall duration, and seasonal antecedent rainfall. This note shows how such relationships can be interpreted using a periodic steady-state solution to the well-known linear pressure diffusion equation. Normalization of the governing equation yields a characteristic response time that is a function of soil thickness, saturated hydraulic conductivity, and pre-storm effective porosity, and which is analogous to the travel time of a piston wetting front. The effects of storm frequency and magnitude are also successfully quantified using dimensionless attenuation factors and lag times.

Haneberg, W.C. (New Mexico Bureau of Mines and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, NM (United States))

1991-11-01

238

Solid vapor pressure for five heavy PAHs via the Knudsen effusion method.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are compounds resulting from incomplete combustion and many fuel processing operations, and they are commonly found as subsurface environmental contaminants at sites of former manufactured gas plants. Knowledge of their vapor pressures is the key to predict their fate and transport in the environment. The present study involves five heavy PAHs, i.e. benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, and dibenz[a,h]anthracene, which are all as priority pollutants classified by the US EPA. The vapor pressures of these heavy PAHs were measured by using Knudsen effusion method over the temperature range of 364 K to 454 K. The corresponding values of the enthalpy of sublimation were calculated from the Clausius-Clapeyron equation. The enthalpy of fusion for the 5 PAHs was also measured by using differential scanning calorimetry and used to convert earlier published sub-cooled liquid vapor pressure data to solid vapor pressure in order to compare with the present results. These adjusted values do not agree with the present measured actual solid vapor pressure values for these PAHs, but there is good agreement between present results and other earlier published sublimation data. PMID:22021935

Fu, Jinxia; Suuberg, Eric M

2011-11-01

239

Saturation meter  

DOEpatents

A saturation meter for use in a pressurized water reactor plant comprising a differential pressure transducer having a first and second pressure sensing means and an alarm. The alarm is connected to the transducer and is preset to activate at a level of saturation prior to the formation of a steam void in the reactor vessel.

Gregurech, S.

1984-08-01

240

Vaporization of sediments with a pulsed transverse excitation at atmospheric pressure (TEA) CO2 laser system  

Microsoft Academic Search

A transverse excitation at atmospheric pressure (TEA) pulsed CO2 laser equipped with an adjunct called a Lasertrace was used to generate vapor and\\/or particulates from sediment samples. The material thus obtained can be transferred to analytical systems for analysis making possible the analysis of solids by techniques previously suitable only for liquids or gases. Approximately one milligram of vapor and\\/or

N. R. Smyrl; H. G. King Jr.

1981-01-01

241

Composition and temperature of the multicomponent liquid-vapor system under isoenthalpic pressure variations  

Microsoft Academic Search

A method based on Gibbs energy minimization is suggested for calculating the equilibrium composition of multicomponent liquid-vapor\\u000a two-phase systems under isoenthalpic pressure variations. The numerical computational procedure invokes ideas of statistical\\u000a physics and nonequilibrium thermodynamics. The thermodynamic parameters of the solution and vapor are determined using a cubic\\u000a equation of state. The computational method is illustrated by particular calculations and

I. V. Derevich; V. A. Pershukov

2008-01-01

242

Mass-Spectrometric and Vapor Pressure Studies on the Sublimation of Realgar (As4S4)  

Microsoft Academic Search

The nature of the sublimation process for the molecular solid realgar (As4S4) has been investigated using mass spectrometric and vapor pressure techniques. Vapor originating from the congruent sublimation of this compound is composed predominantly of As4S4(g) molecules, with smaller concentrations of other species. Of these latter species, those of As4S3, As4, and As2 are believed to originate from partial decomposition

Zuhair A. Munir; Harold F. Winters

1971-01-01

243

The vapor pressures of supercooled HNO3\\/H2O solutions  

Microsoft Academic Search

A procedure utilizing the Gibbs-Duhem relation is used to extrapolate vapor pressures of supercooled HNO3 mixtures to 190 K. Values of A and B from the equation logP=A-B\\/T are presented for nitric acid solutions between 0.20 and 0.25 mole fraction HNO3. In the stratosphere, if sufficient HNO3 vapor is present because it has not come into equilibrium with the nitric

David R. Hanson

1990-01-01

244

The vapor pressures of supercooled HNO3\\/H2O solutions  

Microsoft Academic Search

A procedure utilizing the Gibbs-Duhem relation is used to extrapolate vapor pressures of supercooled HNO3 mixtures to 190 K. Values of A and B from the equation logP = A ? B\\/T are presented for nitric acid solutions between 0.20 and 0.25 mole fraction HNO3. In the stratosphere, if sufficient HNO3 vapor is present because it has not come into

David R. Hanson

1990-01-01

245

The vapor pressures of supercooled HNO sub 3 \\/H sub 2 O solutions  

Microsoft Academic Search

A procedure utilizing the Gibbs-Duhem relation is used to extrapolate vapor pressures of supercooled HNO mixtures to 190 K. Values of A and B from the equation logP = A - B\\/T are presented for nitric acid solutions between 0.20 and 0.25 mole fraction HNO. In the stratosphere, if sufficient HNO vapor is present because it has not come into

1990-01-01

246

Vapor Pressure Assisted Void Growth and Cracking of Polymeric Films and Interfaces  

Microsoft Academic Search

Pores and cavities form at filler particle-polymer matrix interfaces, at polymer film-silicon substrate interfaces as well as in molding compounds of IC packages. Moisture diffuses to these voids. During reflow soldering, surface mount plastic encapsulated devices are exposed to temperatures between 210 to 260C. At these temperatures, the condensed moisture vaporizes. The rapidly expanding water vapor can create internal pressures

L. Cheng; T. F. Guo

2003-01-01

247

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals  

SciTech Connect

Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950[degree]C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

Lee, S.H.D.; Teats, F.G.; Swift, W.M. (Argonne National Lab., IL (United States)); Banerjee, D.D. (Illinois Clean Coal Inst., Carterville, IL (United States))

1993-01-01

248

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals  

SciTech Connect

Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950{degree}C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

Lee, S.H.D.; Teats, F.G.; Swift, W.M. [Argonne National Lab., IL (United States); Banerjee, D.D. [Illinois Clean Coal Inst., Carterville, IL (United States)

1993-04-01

249

Effects of vapor pressure on thermodynamic equilibrium in multiphase flow for thermochemical hydrogen production  

NASA Astrophysics Data System (ADS)

This paper examines the effects of H2O vapor pressure on the equilibrium conditions of a CuCl2 hydrolysis reactor in the thermochemical Cu-Cl cycle of hydrogen production. A new predictive model is developed to determine the minimum steam requirement in the reactor based on the chemical equilibrium condition, reactor pressure and fraction of gaseous reactant. Experimental data, at three separate vapour pressures of steam, compared well with the new predictive formulation.

Pope, K.; Naterer, G. F.; Wang, Z. L.

2013-08-01

250

Laboratory measurement of capillary pressure-saturation relationships in a rock fracture  

NASA Astrophysics Data System (ADS)

A laboratory technique has been developed to measure the hysteretic relationship between capillary pressure and fluid saturation for a rough-walled rock fracture under different states of normal stress. The technique incorporates a loading system and a uniquely designed capillary barrier to the nonwetting phase which allows for fracture closure and provides excellent hydraulic connection of the wetting phase in the fracture with external pressure control. The method is applied to a single, rough-walled fracture in limestone using oil and water as the nonwetting and wetting phase, respectively. The measured capillary pressure curves were found to be well represented by a Brooks-Corey porous media capillary pressure function. A distinct entry pressure, giving rise to initial nonwetting phase invasion, was observed in each test. It was found that the inferred aperture distributions became less skewed with increased normal load. These aperture distributions were inferred using one of three conceptual models presented for nonwetting phase invasion of a rough-walled fracture under conditions of main drainage.

Reitsma, Stanley; Kueper, Bernard H.

1994-04-01

251

Modeling atomization processes in high-pressure vaporizing sprays  

NASA Astrophysics Data System (ADS)

The theoretical basis and numerical implementation of KIVA, a multidimensional computer code for the simulation of atomization and vaporization processes in the injection of a liquid through a round hole into a compressed gas, are described. KIVA is based on the blob-injection model of Reitz and Diwakar (1987), taking into account the effects of liquid inertia, surface tension, and the aerodynamic forces on the jet, as well as drop collision and coalescence and the effect of drops on turbulence in the gas. The predictions of KIVA for different injection regimes are compared with published experimental data in extensive graphs, and good agreement is demonstrated.

Reitz, Rolf D.

252

Pulmonary atresia with ventricular septal defect: a case for central venous pressure and oxygen saturation monitoring.  

PubMed Central

A 21-year-old patient with pulmonary atresia and ventricular septal defect (PA-VSD) was admitted to the hospital for tubal ligation. Invasive arterial and central venous (CVP) pressure, pulse oximetric oxygen saturation (SpO2), and (from the tip of oximetric central venous catheter) central venous oxygen saturation (ScvO2) and oxygen extraction rate (ExO2) were continuously monitored. Heart rate (range: 68-75 beat/min), mean arterial pressure (80-90 mmHg), CVP (7-10 mmHg), SpO2 (79-90 percent), ScvO2 (57-70 percent), and ExO2 (21-30 percent) remained stable during epidural anesthesia and transvaginal sterilization. Following an overnight stay (peak SpO2 92 percent; peak ScvO2 71 percent; through ExO2 21 percent), the oxygen data returned to baseline on awakening (SpO2 < 80 percent, ScvO2 < 55 percent, ExO2 > 35 percent), and the patient was discharged. In PA-VSD, a single-outlet double-ventricle anomaly, CVP reflects the preload of systemic ventricle. As the mixed venous oxygen saturation cannot be defined, ScvO2 is the best available indicator of the whole body oxygen consumption. Continuous monitoring of CVP, ScvO2 and ExO2 in the superior vena cava may provide more insight into the response to anesthesia and surgery in patients with PA-VSD. Images Figure 1

Weiss, B. M.; Atanassoff, P. G.; Jenni, R.; Walder, B.; Wight, E.

1998-01-01

253

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

PubMed

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. PMID:19371050

Duan, Fei; Ward, C A

2009-07-01

254

Scaling Capillary Pressure Head - Saturation Relationships for Saprolite: Correction for Uncertainty Introduced by Pressure Cell Measurements on Tall Columns  

NASA Astrophysics Data System (ADS)

Dense non-aqueous phase liquids (DNAPL's) are important contaminants at many hazardous waste disposal sites. Relatively little information is available on DNAPL behavior in heterogeneous porous media such as fractured saprolite. We measured air-water and FluorinertTM (a non-toxic DNAPL surrogate)-water capillary pressure head (hc)-saturation (S) relationships close to saturation on an 18-cm long by 10-cm diameter undisturbed column of fractured shale saprolite. As hc increased, the pore volume invaded increased gradually rather than stepwise, indicating a range of fracture sizes with no clear division between pores in the fine-grained matrix and the fracture network. Microscopic examination of the pore structure in thin-sections of the saprolite supported this interpretation of the data. A fractal model, equivalent to the empirical Brooks and Corey model with zero residual saturation, was used to parameterize the S(hc) curves. The best-fit parameters were 19.54 and 30.10 cm for the displacement pressure head (hd) and 2.971 and 2.956 for the mass fractal dimension (D), for the air-water and FluorinertTM-water curves respectively. Parameters corrected for the hydrostatic fluid distribution within the column were obtained using the approach of Liu and Dane (1995). The corresponding corrected parameters were 26.45 and 16.23 cm for hc, and 2.966 and 2.966 for D. The correction procedure had a large impact on the form of the FluorinertTM-water curve, and relatively little impact on the form of the air-water curve. The uncorrected and corrected parameters for the air-water curve were then used to predict the corrected FluorinertTM-water curve using Leverett's function. Both sets of parameters produced predicted curves that explained over 99% of the variation in the FluorinertTM-water curve, with the corrected parameters producing a slightly better 1:1 relationship than the uncorrected parameters. Our results indicate that measured S(hc) curves for DNAPL-water systems are sensitive to the hydrostatic fluid distribution within the column. Air intrusion experiments can be used, in conjunction with Leverett's function, to predict the entry of DNAPL's into water-saturated heterogeneous porous media, and the error introduced by not correcting these measurements is relatively small.

Perfect, E.; McKay, L.; Driese, S.; Dane, J.; Kammerer, G.

2002-12-01

255

Synthetic fluid inclusions. V. Solubility relations in the system NaCl-KCl-H sub 2 O under vapor-saturated conditions  

Microsoft Academic Search

Vapor-saturated solubility relationships in the system NaCl-KCl-HO have been determined by experimentally synthesizing fluid inclusions in quartz in the presence of known brine compositions and then measuring the dissolution temperatures of halite and\\/or sylvite daughter crystals within the inclusions using a microscope equipped with a heating stage. These data, along with other literature values have been used in a stepwise

S. M. Sterner; D. L. Hall; R. J. Bodnar

1988-01-01

256

Synthetic fluid inclusions. V. Solubility relations in the system NaCl-KCl-H 2 O under vapor-saturated conditions  

Microsoft Academic Search

Vapor-saturated solubility relationships in the system NaCl-KCl-H 2 O have been determined by experimentally synthesizing fluid inclusions in quartz in the presence of known brine compositions and then measuring the dissolution temperatures of halite and\\/or sylvite daughter crystals within the inclusions using a microscope equipped with a heating stage. These data, along with other literature values have been used in

S. Michael Sterner; Donald L. Hall; Robert J. Bodnar

1988-01-01

257

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

Code of Federal Regulations, 2010 CFR

...COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo...7 psia). When table 1 references this section, the containment system must have a: (a) Tank pressure gauge at the...

2009-10-01

258

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

Code of Federal Regulations, 2012 CFR

...COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo...7 psia). When table 1 references this section, the containment system must have a: (a) Tank pressure gauge at the...

2012-10-01

259

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

...COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo...7 psia). When table 1 references this section, the containment system must have a: (a) Tank pressure gauge at the...

2011-10-01

260

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

Code of Federal Regulations, 2010 CFR

...COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor return for cargo...7 psia). When table 1 references this section, the containment system must have a: (a) Tank pressure gauge at the...

2010-10-01

261

Pressure sensitivity of the vapor-cell atomic clock  

Microsoft Academic Search

Although atomic clocks have very low levels of frequency instability, they are nonetheless sensitive (albeit slightly) to various environmental parameters, including temperature, power supply voltage, and dc magnetic fields. In the terrestrial environment, however, atmospheric pressure (i.e., the air's molecular density) is not generally included in this list, because the air's density variations near the surface of the Earth will

Gebriel Iyanu; He Wang; James Camparo

2009-01-01

262

Activities and vapor pressures of aqueous sulfuric acid solutions  

Microsoft Academic Search

A quantitative interpretation of the conditions leading to the formation of sulfuric acid in whatever system requires the knowledge of the thermodynamic properties of aqueous sulfuric acid solutions under the conditions of temperature and partial pressures at which the liquid phase is likely to nucleate. Surprisingly, in the light of the importance of sulfuric acid in industrial technology, such data

Bolsaitis

1986-01-01

263

Chemical Laser Action in Low Pressure Metal Vapor Flames  

Microsoft Academic Search

Chemiluminescence in the visible has indicated the production of electronically excited products in the low pressure reactions of alkaline earlh metals with oxygen, halogens, halogen compounds and other oxidants. Thermochemical calculations on many such systems have indicated energy release more than adequate for electronic excitation of the product molecules. Comparisons of radiative lifetimes, rates of chemical reaction and col-lisional de-excitation

M. L. ZWILLENBERG; D. W. NAEGELI; I. GLASSMAN

1973-01-01

264

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, April 1, 1996--June 30, 1996  

SciTech Connect

As the world continues to deplete its petroleum reserves, then heavy crude oil, coal liquids, and other heavy fossil fuels may be required to meet the world energy needs. Heavy fossil fuels contain molecules that are large and more aromatic and that contain more heteroatoms than those found in liquid crude oil. There is also significant current interest in general area of coal pyrolysis, particularly with respect to comprehensive models of this complicated phenomenon. This interest derives from central role of pyrolysis in all thermally driven coal conversion processes - gasification, combustion, liquefaction, mild gasification, or thermal beneficiation. There remain several key data needs in these application areas. Among them is a need for a more reliable correlation for prediction of the vapor pressures of heavy, primary coal tars. Such information is important in design of all coal conversion processes, in which the volatility of tarry products is of major concern. This paper presents work on the vapor pressures of coal tars using the continuous knudsen effusion technique.

Suuberg, E.M.; Oja, V.; Lilly, W.D.

1997-12-31

265

H2SO4 vapor pressure of sulfuric acid and ammonium sulfate solutions  

NASA Astrophysics Data System (ADS)

Few measurements of H2SO4 vapor pressure have been made for sulfuric acid in the temperature and concentration ranges of atmospheric interest because of the very low pressures involved (below 10-4 Pa, or 10-6 torr); no such measurements appear to have been made for sulfuric acid solutions neutralized with ammonia. This work presents measurements of H2SO4 vapor pressure for aqueous sulfuric acid solutions between 55 and 77 wt% H2SO4 (corresponding to about 5-25% relative humidity), ammonium sulfate solids at low humidities, and partially neutralized sulfate solutions with [NH4+]: [SO4=] ratios between 0.13 and 1.0. The vapor pressure data collected over sulfuric acid solutions generally agree with the predictions of Ayers, et al. [1980], although positive deviation was observed for the more dilute solutions. The good agreement between this measurement and previous efforts by absolute techniques suggests that the evaporative coefficient for the H2SO4-H2O system is near unity. H2SO4 vapor pressures over solid ammonium sulfate were measured between 27C and 60C; the data were fitted to In p = A/T + B, with A = -5928 and B = -3.77. The H2SO4 vapor pressures of mixed H2SO4-H2O-(NH4)2SO4 solutions dropped significantly as the [NH4+]:[SO4=] ratio exceeded 0.5. The results suggest that ammonia could very effectively stabilize molecular clusters of sulfuric acid and water in the atmosphere against evaporation, leading to rates of new particle formation higher than those predicted by binary H2SO4-H2O theory.

Marti, James J.; Jefferson, Anne; Cai, Xiao Ping; Richert, Chad; McMurry, Peter H.; Eisele, Fred

1997-02-01

266

Vapor pressure and normal boiling point predictions for pure methyl esters and biodiesel fuels  

Microsoft Academic Search

Temperature dependent vapor pressures of the methyl esters of fourteen fatty acids that are commonly present in biodiesel fuels were predicted by the Antoine equation and a group contribution method. The predicted boiling points of these esters up to a pressure of 100mmHg were within 1.0% of reported data for these two methods. Normal boiling points were determined from both

W. Yuan; A. C. Hansen; Q. Zhang

2005-01-01

267

A New 3HE Vapor-Pressure Equation on the ITS-90 Scale  

SciTech Connect

A coupled set of new 3He vapor pressure equations have been developed in the range from 2.6 mK to the critical temperature, which has greatly extended the lower limit of the ITS-90 temperature scale. In the overlapped interval from 0.65 K to 3.2 K, the new equation smoothly joins with the ITS-90 3He equation to within +/-50 {mu}K for a given pressure.

Huang, Y. H.; Chen, G. B. [Cryogenics Laboratory, Zhejiang University, Hangzhou, Zhejiang Province, 310027 (China)

2006-04-27

268

High-pressure vaporliquid equilibria of argon + carbon dioxide + 2-propanol  

Microsoft Academic Search

The high-pressure phase equilibria for a heterogeneously catalyzed oxidation reaction in a carbon dioxide-expanded liquid were investigated. For safety argon was used as a substitute for oxygen in this study. A visual synthetic technique was used to determine the vaporliquid equilibria data for the systems carbon dioxide+argon+2-propanol and carbon dioxide+argon+2-propanol+acetone+water at 313K and pressures from 6.9 to 15.0MPa.

Michael J. Lazzaroni; David Bush; Charles A. Eckert; Roger Glser

2006-01-01

269

Vapor pressures and thermodynamics of oxygen-containing polycyclic aromatic hydrocarbons measured using Knudsen effusion  

SciTech Connect

Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl, and nitro groups, specifically 2-nitrofluorene, 9-fluorenecarboxylic acid, 2-fluorenecarboxaldehyde, 2-anthracenecarboxylic acid, 9-anthracenecarboxylic acid, 9-anthraldehyde, 1-nitropyrene, 1-pyrenecarboxaldehyde, and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 g/mol, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421 K. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, nonoxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of -CHO, -COOH, and -NO{sub 2} groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs.

Goldfarb, J.L.; Suuberg, E.M. [Brown University, Providence, RI (United States). Division of Engineering

2008-06-15

270

Estimates of Pan Evaporation from Mean Maximum Temperature and Vapor Pressure  

Microsoft Academic Search

An equation for estimating pan evaporation has been derived by regression analysis from climatic data of a number of widely separated stations in Australia. The required data are mean maximum temperature, mean vapor pressure, and day length. The equation resembles the bulk aerodynamic (mass transfer) expression, but does not contain a wind parameter.An empirical variate was postulated and compared with

Eugene A. Fitzpatrick

1963-01-01

271

Vapor Pressures and Thermodynamics of Oxygen-Containing Polycyclic Aromatic Hydrocarbons Measured Using Knudsen Effusion  

PubMed Central

Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl and nitro groups, specifically: 2-nitrofluorene; 9-fluorenecarboxylic acid; 2-fluorenecarboxaldehyde; 2-anthracenecarboxylic acid; 9-anthracenecarboxylic acid; 9-anthraldehyde; 1-nitropyrene; 1-pyrenecarboxaldehyde and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 grams per mole, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, non-oxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of CHO,COOH, and NO2 groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs.

Goldfarb, Jillian L.

2013-01-01

272

Isothermal vapor-liquid equilibrium data for binary systems containing ethane at high pressures  

Microsoft Academic Search

Isothermal vapor-liquid equilibrium data for binary systems containing carbon dioxide at high pressure have been reported previously. In those studies, methanol, acetone, methyl acetate, ethyl ether, n-hexane, and benzene were chosen as the solvent components. In this study, the same solvent components were used and carbon dioxide was replaced with ethane having similar critical temperature to that of carbon dioxide.

F. Sano; K. Ohgaki; Takashi Katayama

1976-01-01

273

On-Line Coating of Glass with Tin Oxide by Atmospheric Pressure Chemical Vapor Deposition.  

National Technical Information Service (NTIS)

Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The ...

A. H. McDaniel J. F. Sopko M. Allendorf M. Li W. G. Houf Y. Chae

2006-01-01

274

Partial vapor pressure of CO 2 and H 2S over aqueous methyldiethanolamine solutions  

Microsoft Academic Search

A new apparatus is presented to measure low partial vapor pressures of acid gas. New measurements are given for carbon dioxide and hydrogen sulfide into aqueous solutions of methyldiethanolamine (MDEA). Large discrepancies among the measured VLE data and the slopes of their solubility curves are found between the authors due to systematic experimental errors, and particularly in the low acid

B. Lemoine; Yi-Gui Li; R. Cadours; C. Bouallou; D. Richon

2000-01-01

275

Partial and Total Vapor Pressures over Molten Bi2Te3.  

National Technical Information Service (NTIS)

The total vapor pressure, P(Sigma), over Bi2Te3 (1) has been determined between 980 and 1169K by using a new manometric technique. The lower end of an evacuated, inverted, fused silica U-tube was immersed in a large reservoir of melt inside a transparent ...

F. T. Smith R. F. Brebrick

1971-01-01

276

Measurement of partial vapor pressure of ammonia over acid ammonium sulfate solutions by an integral method  

Microsoft Academic Search

We present a simple, integral, passive method for measuring partial vapor pressure. Integral methods are useful tools when dealing with very low concentrations because collection over extended periods increases the analytical sensitivity. Passive methods have the advantage of not introducing constraints external to the system. The principle of the method used here is to selectively react the substance in the

P. Koutrakis; B. Aurian-Blajeni

1993-01-01

277

Prediction of solid vapor pressures for organic and inorganic compounds using a neural network  

Microsoft Academic Search

A method to estimate solid vapor pressures (PS) for organic and inorganic compounds using an artificial neural network (ANN) is presented. The proposal consists of training an ANN with PS data of a defined group of substances as a function of temperature, including as learning variable five physicochemical properties to discriminate among the different substances. The following properties were considered:

Juan A. Lazzs

2009-01-01

278

Impulse Electric Breakdown of Air and Water Vapor at Increased Pressure.  

National Technical Information Service (NTIS)

The results of an investigation of the volt-second characteristics of the electric breakdown of air and water vapor in a nonhomogeneous electric field at pressures of up to 40 atmospheres for a surge voltage effect time of from 0.0000002 to 0.000002 s are...

A. A. Vorobev A. T. Chepikov I. I. Kalyatskii V. V. Krivko

1972-01-01

279

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

PubMed

Dibasic calcium phosphate occurs as an anhydrate (DCPA; CaHPO4 ) and as a dihydrate (DCPD; CaHPO4 2H2 O). 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 210C 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 100C and 140C, respectively. Under reduced pressure, conversion to the anhydrate was incomplete even at 300C. 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. 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 100:1456-1466, 2011. PMID:24081471

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

2010-12-06

280

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

PubMed

Dibasic calcium phosphate occurs as an anhydrate (DCPA; CaHPO(4)) and as a dihydrate (DCPD; CaHPO(4)2H(2)O). 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 210C 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 100C and 140C, respectively. Under reduced pressure, conversion to the anhydrate was incomplete even at 300C. 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. 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci. PMID:21136556

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

2010-12-01

281

Thermal modeling of tubular horizontal hot-wall low pressure chemical vapor deposition reactors  

Microsoft Academic Search

Low pressure chemical vapor deposition (LPCVD) reactors are intensively used in the microelectronics industry for depositing thin films of polysilicon. In this paper, a thermal model is presented, involving computations of the water temperature and taking into account radiative exchanges occurring inside an LPCVD reactor, with non-isothermal tube walls. This thermal model was incorporated in a global multiwafer model (CVD1),

C. Azzaro; J. P. Couderc

1995-01-01

282

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

Code of Federal Regulations, 2011 CFR

...Testing Materials Standard D 323 (incorporated by reference, see § 30.01-3), Method of Test for Vapor Pressure of Petroleum Products. This Standard is available at Headquarters for reading purposes or it may be purchased from the Society at...

2011-10-01

283

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

Code of Federal Regulations, 2012 CFR

...Testing Materials Standard D 323 (incorporated by reference, see § 30.01-3), Method of Test for Vapor Pressure of Petroleum Products. This Standard is available at Headquarters for reading purposes or it may be purchased from the Society at...

2012-10-01

284

Calculation of vapor pressure curves for hydroxy benzoic acid derivatives using thermogravimetry  

Microsoft Academic Search

This study aims at providing a simple thermogravimetric method in estimating the vapor pressure characteristics using the Antoine equation as the analytical tool. The heat treatment for the majority of benzoic acid derivatives follows zero order rate processes that are in good correlation with their evaporation process. The optimum conditions for the rising temperature experiments were found when the heating

Koustuv Chatterjee; David Dollimore; Kenneth S Alexander

2002-01-01

285

CONTAMINANT VAPOR TRANSPORT IN A DEEP VADOSE ZONE: INFLUENCES OF BAROMETRIC PRESSURE, DIFFUSION, AND DENSITY-DRIVEN FLOW  

Microsoft Academic Search

Daily atmospheric pressure fluctuations cause gas-pressure variations in the subsurface. These pressure variations serve as driving forces for vapor transport. The objective of this research is to investigate the influence and relative importance of barometric-pressure fluctuations in deep vadose zones on transport of organic-contaminant vapors compared to gas-phase diffusion and density-driven transport. A numerical three-dimensional multiphase- fluid-flow model is calibrated

John E. McCray; Wayne Downs; Ronald W. Falta; L. Todd Housley

286

SIMPOL.1: a simple group contribution method for predicting vapor pressures and enthalpies of vaporization of multifunctional organic compounds  

NASA Astrophysics Data System (ADS)

The SIMPOL.1 group contribution method is developed for predicting the liquid vapor pressure poL (atm) and enthalpy of vaporization ? Hvap (kJ mol-1) of organic compounds as functions of temperature (T). For each compound i, the method assumes log10poL,i (T)=∑k?k,ibk(T) where ?k,i is the number of groups of type k, and bk (T) is the contribution to log10poL,i (T) by each group of type k. A zeroeth group is included that uses b0 (T) with ?0,i=1 for all i. A total of 30 structural groups are considered: molecular carbon, alkyl hydroxyl, aromatic hydroxyl, alkyl ether, alkyl ring ether, aromatic ether, aldehyde, ketone, carboxylic acid, ester, nitrate, nitro, alkyl amine (primary, secondary, and tertiary), aromatic amine, amide (primary, secondary, and tertiary), peroxide, hydroperoxide, peroxy acid, C=C, carbonylperoxynitrate, nitro-phenol, nitro-ester, aromatic rings, non-aromatic rings, C=C-C=O in a non-aromatic ring, and carbon on the acid-side of an amide. The T dependence in each of the bk (T) is assumed to follow b(T)=B1/T+B2+B3T+B4ln T. Values of the B coefficients are fit using an initial basis set of 272 compounds for which experimentally based functions po L,i=fi (T) are available. The range of vapor pressure considered spans fourteen orders of magnitude. The ability of the initially fitted B coefficients to predict poL values is examined using a test set of 184 compounds and a T range that is as wide as 273.15 to 393.15 K for some compounds. ?FIT is defined as the average over all points of the absolute value of the difference between experimental and predicted values of log10poL,i (T). After consideration of ?FIT for the test set, the initial basis set and test set compounds are combined, and the B coefficients re-optimized. For all compounds and temperatures, ?FIT=0.34: on average, poL,i (T) values are predicted to within a factor of 2. Because d(log10 poL,i (T))d(1/T) is related to the enthalpy of vaporization ?Hvap,i, the fitted B provide predictions of ?Hvap,i based on structure.

Pankow, J. F.; Asher, W. E.

2008-05-01

287

SIMPOL.1: A simple group contribution method for predicting vapor pressures and enthalpies of vaporization of multifunctional organic compounds  

NASA Astrophysics Data System (ADS)

The SIMPOL.1 group contribution method is developed for predicting the liquid vapor pressure pLo (atm) and enthalpy of vaporization ?Hvap (kJ mol-1) of organic compounds as functions of temperature (T). For each compound i, the method assumes log10pL,io(T)=?k?k,ibk(T) where ?k,i is the number of groups of type k, and bk(T) is the contribution to log10 pL,io(T) by each group of type k. A zeroeth group is included that uses b0(T) with ?0,i=1 for all i. A total of 30 structural groups are considered: molecular carbon, alkyl hydroxyl, aromatic hydroxyl, alkyl ether, alkyl ring ether, aromatic ether, aldehyde, ketone, carboxylic acid, ester, nitrate, nitro, alkyl amine (primary, secondary, and tertiary), aromatic amine, amide (primary, secondary, and tertiary), peroxide, hydroperoxide, peroxy acid, C=C, carbonylperoxynitrate, nitro-phenol, nitro-ester, aromatic rings, non-aromatic rings, C=C-C=O in a non-aromatic ring, and carbon on the acid-side of an amide. The T dependence in each of the bk(T) is assumed to follow b(T)=B1/T+B2+B3T+B4lnT. Values of the B coefficients are fit using an initial basis set of 272 compounds for which experimentally based functions pL,io=fi(T) are available. The range of vapor pressure considered spans fourteen orders of magnitude. The ability of the initially fitted B coefficients to predict pLo values is examined using a test set of 161 compounds and a T range that is as wide as 273.15 to 393.15 K for some compounds. ?FIT is defined as the average over all points of the absolute value of the difference between experimental and predicted values of log10pL,io(T). After consideration of ?FIT for the test set, the initial basis set and test set compounds are combined, and the B coefficients re-optimized. For all compounds and temperatures, ?FIT=0.34: on average, pL,io(T) values are predicted to within a factor of 2. Because d(log10pL,io(T))/d(1/T) is related to the enthalpy of vaporization ?Hvap,i, the fitted B provide predictions of ?Hvap,i based on structure.

Pankow, J. F.; Asher, W. E.

2007-08-01

288

Thermodynamic properties and vapor pressures of polar fluids from a four-parameter corresponding-states method  

NASA Astrophysics Data System (ADS)

A recently proposed extended Lee-Kesler corresponding-states method (ELK) for polar fluids which accurately predicts compressibility factors and departure functions is considered. Tables of polar deviation functions have been generated and values of the shape/size and polar parameters for 52 polar fluids have been calculated, allowing the method to be used for quick hand calculations in addition to the previous, more accurate, computer applications. Additionally, vapor pressures of 44 pure polar fluids were computed using the full version of the ELK and the equality of the Gibbs free energy criterion for phase equilibrium. An ELK vapor pressure correlation is proposed which is essentially numerically equivalent to, but computationally simpler than, the former method. Computed vapor pressures agree with experimental values as well or better than other vapor pressure equations designed exclusively for vapor pressure prediction of polar fluids.

Wilding, W. V.; Johnson, J. K.; Rowley, R. L.

1987-11-01

289

The formation and behavior of {open_quotes}vapor lock{close_quotes} pressure seals and associated hydrocarbon accumulations in geologically young basins  

SciTech Connect

This paper demonstrates a mechanism for the formation of geopressure and hydrocarbon accumulations in geologically young basins (e,g., Gulf of Mexico). Gas exsolving from solution in response to changes in temperature create a relative permeability barrier that restricts vertical fluid flow locally. Continued gas dissolution in source rock, transport and subsequent exsolution at shallower depths maintain the {open_quotes}vapor lock{close_quotes} seal. Any sands that are found within the pressure seal fill preferentially with the nonwetting gas and oil. Further migration of the trapped hydrocarbons is restricted by the capillary entry pressures of the surrounding shales; thus, capillary entry effects enhance the sealing nature of the pressure barrier. Numerical simulations demonstrate the viability of this model for the formation of geopressured reservoirs in young basins, and show that two distinct pressure seals can form under certain conditions. The model incorporates salient features from the Gulf of Mexico, including spatially-variable heat flux, methane and CO{sub 2} generation and transport, and a low-permeability shale as the continuous rock fabric. Steady state isotherms exhibit significant relief due to the variable heat flux, and gas exsolves from solution along two distinct isotherms. The gas forms a relative permeability barrier that restricts vertical fluid flow. As the gas saturation exceeds a critical saturation, any sands found within the pressure seals fill with the non-wetting hydrocarbons. Gas is trapped within the sands by capillary entry pressures of the surrounding shales, improving the sealing nature of the pressure barrier. Sensitivity studies show that specific seat geometry is sensitive to the variability in heat flow, gas content of the aqueous phase, and relative permeability and capillary pressure characteristics of both the sand and shale; however, one or more vapor lock seals form under a variety of conditions.

Benzing, W.M.; Shook, G.M. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1996-09-01

290

Surface tension, coexistence curve, and vapor pressure of binary liquid-gas mixtures  

SciTech Connect

The objective of this paper is to present measurements of the vapor pressure, capillary coefficient, and refractive index of four binary mixtures, CO/sub 2/-SF/sub 6/, R14-SF/sub 6/, SF/sub 6/-R13B1, and SF/sub 6/-R22, at liquid-vapor equilibrium at different average concentrations. The measuring temperature range covered the entire liquid-vapor region from the triple line up to the critical point. The capillary coefficient was determined by means of the capillary rise method; the refractive index, by measuring the angle of refraction of a light beam passing through a prism and the sample. In order to obtain the liquid-vapor densities of pure substances the Lorentz-Lorenz relation can be used. However, in applying this relation to calculate the liquid-vapor densities of a mixture, one may need the concentrations of both the liquid and the vapor phase, which are, for the most part, quite different from the average concentration of the mixture. Calculating the concentrations of both fluid phases with the aid of an equation of state and comparing with measurements, we could show that the molar refraction coefficient of the mixtures can be simply determined from the average concentration and the molar refraction coefficients of their pure components. The surface tension of the mixtures could then be calculated from the measured capillary coefficient and the refractive index with the aid of the Lorentz-Lorenz relation.

Do, V.T.; Straob, J.; Hanley, H.J.M.; Cezairliyan, A.

1986-01-01

291

Vaporization of Uranium Mononitride and Heat of Sublimation of Uranium  

Microsoft Academic Search

The vaporization of uranium mononitride UN has been investigated by the Knudsen effusion technique in combination with a mass spectrometer. The vaporization occurs incongruently by preferential loss of nitrogen forming the two-phase system nitrogen-saturated liquid uraniumuranium-saturated nonstoichiometric uranium mononitride. The vapor pressures of U and N2 have been obtained by silver calibration over the two-phase system UN0.4&sngbnd;UN0.9 in the temperature

Karl A. Gingerich

1969-01-01

292

Theoretical constraints on pure vapor-pressure driven condensation of organics to ultrafine particles  

NASA Astrophysics Data System (ADS)

Organic condensation to freshly nucleated particles contributes substantially to their growth. Here we explore a range of constraints on this process, under the assumption that gas-phase oxidation of organic vapors by hydroxy radical is forming organics with a sufficiently low volatility to condense onto particles in the 2-20 nm size range. To condense but not homogeneously nucleate, vapors need to have saturation concentrations (C*) in the 10-3 - 10-2 ?g m-3 range, and this is exactly the range that gas-phase chemistry is likely to produce. At least half of the observed growth rate of ultrafine particles can be explained by these simple considerations and constraints.

Donahue, N. M.; Trump, E. R.; Pierce, J. R.; Riipinen, I.

2011-08-01

293

Sampler for Collection and Analysis of Low Vapor Pressure Chemical (LVPC) Particulates/Aerosols.  

PubMed

Detection of low vapor pressure chemicals (LVPCs) such as pesticides and other toxic/hazardous materials on various environmental surfaces as well as LVPC aerosols is a significant challenge for current vapor phase detectors. We describe a novel sampling device which utilizes stainless steel screens coated with a sticky polydimethylsiloxane coating for collecting LVPCs aerosolized off of a surface. Results are presented for the collection and detection of a pesticide simulant, dimethyl methylphosphonate sorbed onto silica gel (DMMP/SG), using direct analysis in real time-cylindrical ion trap mass spectrometry (DART-CITMS). PMID:24053780

Ewing, K J; Gibson, D; Sanghera, J; Miklos, F

2013-10-03

294

Comparison of relative permeability fluid saturation capillary pressure relations in the modelling of non-aqueous phase liquid infiltration in variably saturated, layered media  

NASA Astrophysics Data System (ADS)

The characteristic functions relating relative permeabilities and capillary pressures to fluid saturations ( kr- S- Pc models) are of great importance for the modelling of sub-surface multi-phase flow and transport. In order to test their performance and to identify their important parameters, four well-known three-phase kr- S- Pc models have been tested against published experimental data on non-aqueous phase liquid (NAPL) migration in the unsaturated zone. Both homogenous systems and systems with embedded heterogeneities have been analysed. The results show that although there are differences between predictions based on the different models, all models exhibit some common problems and it is not obvious that any one model is more accurate than the other three. However, with the inclusion of a non-linear NAPL tortuosity factor, both the Brooks-Corey-Burdine and van Genuchten-Mualem models yield excellent fits to experimental data. For NAPLs with non-zero spreading coefficients no exact theory currently exists for scaling two-phase capillary pressure-saturation functions to three-phase systems. Different ways of applying the Parker et al. [Parker JC, Lenhard RJ, Kuppusamy T. A parametric model for constitutive properties governing multi-phase flow in porous media. Water Resour Res 1987;23:618-24] scaling method have therefore been tested. It was found that since the NAPL-gas capillary pressure function has the strongest influence on NAPL migration, the scaling procedure should focus on accuracy in this function.

Fagerlund, F. Fritjof; Niemi, Auli; Odn, Magnus

2006-11-01

295

Saturation Energy Density and Line Profile of the Atomic Iodine Laser Transition at High Pressure.  

National Technical Information Service (NTIS)

The saturation energy density of an iodine laser amplifier is proportional to the homogeneous medium line width and inversely proportional to the Einstein coefficient. For good energy extraction high values of the saturation energy density are needed, thu...

M. Galanti W. Thieme K. J. Witte

1980-01-01

296

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false High and low vapor pressure protection for tankships-T...controlled; and (b) Has a high pressure and a low pressure alarm that...controlled; (2) Alarms at a high pressure of not more than 90...

2010-10-01

297

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

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false High and low vapor pressure protection for tankships-T...controlled; and (b) Has a high pressure and a low pressure alarm that...controlled; (2) Alarms at a high pressure of not more than 90...

2009-10-01

298

Determining Pore Pressures Along a Slip Surface Within a Saturated Elastic-Plastic Porous Medium  

NASA Astrophysics Data System (ADS)

Here we consider shear rupture along a slip surface in a fluid-saturated elastic-plastic porous medium, like in landslide and earthquake modeling, and assume that there are different poro-elasto-plastic response properties on the two sides of the slip surface. This different response may be because the fault bordering materials are dissimilar, or just because one side is actively yielding and the other is not, or is yielding but in a different mode. In effect, we are representing a core about a slip surface that divides two similar or contrasting materials. This representation is especially relevant in earthquake rupture dynamics. Studies of mature fault zones have noted a trend of fractured host rock extending 10--100m from the fault, with an ultracataclastic core ~100mm about or to one side of the principal slip surface (e.g., Chester and Chester, Tectonophys, 1998; Chester et al., Columbia Univ Pr, 2004). Furthermore, there is likely to exist a material contrast that may come from accumulating km of slip and a bias in accumulated damage. The local pore pressure at the slip surface influences the rupture dynamics because, through the effective stress concept, it controls the local shear strength along the fault, a feature neglected as a simplification in our preliminary poro-elasto-plastic modeling of dynamic rupture (Viesca et al., JGR, 2008). To determine pore pressures at the slip surface under locally elastic-plastic response, we must consider pore pressure discontinuities about that surface that arise in an undrained treatment of off-fault material and their amelioration within resulting thin diffusive boundary layers, such that pore pressure and fluid mass flux in the normal direction are continuous at the slip surface. Our approach builds on previous work considering the effect of contrasts in poroelastic properties on rupture propagation (Rudnicki and Rice, JGR, 2006; Dunham and Rice, JGR, 2008). Here we find expressions for the undrained pore pressure changes in the thin damage zone adjacent to the slip surface. This expression is dependent on the local fault-normal stresses and fault- parallel strains coupled to the undrained response in the adjacent bulk. Additionally, in the process of determining the pore pressure at the slip surface, we find a diffusivity under elastic-plastic response that is different from the diffusivity of linear poroelasticity theory (e.g., Rice and Cleary, Rev Geophys, 1976). We show how the full inclusion of pore pressure changes by these considerations affects rupture dynamics in explicit dynamic numerical simulations, first checking for validation against the poroelastic results of Dunham and Rice (2008), and then examining the effects relative to the fully undrained elastic-plastic simulations of Viesca et al. (2008) which neglected pore pressure changes on the fault itself.

Viesca, R. C.; Rice, J. R.; Dunham, E. M.

2008-12-01

299

Saturated defect densities of hydrogenated amorphous silicon grown by hot-wire chemical vapor deposition at rates up to 150 {angstrom}/s  

SciTech Connect

Hydrogenated amorphous-silicon (a-Si:H) is grown by hot-wire chemical vapor deposition (HWCVD) at deposition rates (R{sub d}) exceeding 140 {angstrom}/s ({approx}0.8 {mu}m/min). These high rates are achieved by using multiple filaments and deposition conditions different than those used to produce our standard 20 {angstrom}/s material. With proper deposition parameter optimization, an AM1.5 photo-to-dark-conductivity ratio of 10{sup 5} is maintained at an R{sub d} up to 130 {angstrom}/s, beyond which it decreases. In addition, the first saturated defect densities of high R{sub d} a-Si:H films are presented. These saturated defected densities are similar to those of the best HWCVD films deposited at 5--8 {angstrom}/s, and are invariant with R{sub d} up to 130 {angstrom}/s.

Mahan, A. H.; Xu, Y.; Nelson, B. P.; Crandall, R. S.; Cohen, J. D.; Palinginis, K. C.; Gallagher, A. C.

2001-06-11

300

Observations on vapor pressure in SPR caverns : sources.  

SciTech Connect

The oil of the Strategic Petroleum Reserve (SPR) represents a national response to any potential emergency or intentional restriction of crude oil supply to this country, and conforms to International Agreements to maintain such a reserve. As assurance this reserve oil will be available in a timely manner should a restriction in supply occur, the oil of the reserve must meet certain transportation criteria. The transportation criteria require that the oil does not evolve dangerous gas, either explosive or toxic, while in the process of transport to, or storage at, the destination facility. This requirement can be a challenge because the stored oil can acquire dissolved gases while in the SPR. There have been a series of reports analyzing in exceptional detail the reasons for the increases, or regains, in gas content; however, there remains some uncertainty in these explanations and an inability to predict why the regains occur. Where the regains are prohibitive and exceed the criteria, the oil must undergo degasification, where excess portions of the volatile gas are removed. There are only two known sources of gas regain, one is the salt dome formation itself which may contain gas inclusions from which gas can be released during oil processing or storage, and the second is increases of the gases release by the volatile components of the crude oil itself during storage, especially if the stored oil undergoes heating or is subject to biological generation processes. In this work, the earlier analyses are reexamined and significant alterations in conclusions are proposed. The alterations are based on how the fluid exchanges of brine and oil uptake gas released from domal salt during solutioning, and thereafter, during further exchanges of fluids. Transparency of the brine/oil interface and the transfer of gas across this interface remains an important unanswered question. The contribution from creep induced damage releasing gas from the salt surrounding the cavern is considered through computations using the Multimechanism Deformation Coupled Fracture (MDCF) model, suggesting a relative minor, but potentially significant, contribution to the regain process. Apparently, gains in gas content can be generated from the oil itself during storage because the salt dome has been heated by the geothermal gradient of the earth. The heated domal salt transfers heat to the oil stored in the caverns and thereby increases the gas released by the volatile components and raises the boiling point pressure of the oil. The process is essentially a variation on the fractionation of oil, where each of the discrete components of the oil have a discrete temperature range over which that component can be volatized and removed from the remaining components. The most volatile components are methane and ethane, the shortest chain hydrocarbons. Since this fractionation is a fundamental aspect of oil behavior, the volatile component can be removed by degassing, potentially prohibiting the evolution of gas at or below the temperature of the degas process. While this process is well understood, the ability to describe the results of degassing and subsequent regain is not. Trends are not well defined for original gas content, regain, and prescribed effects of degassing. As a result, prediction of cavern response is difficult. As a consequence of this current analysis, it is suggested that solutioning brine of the final fluid exchange of a just completed cavern, immediately prior to the first oil filling, should be analyzed for gas content using existing analysis techniques. This would add important information and clarification to the regain process. It is also proposed that the quantity of volatile components, such as methane, be determined before and after any degasification operation.

Munson, Darrell Eugene

2010-05-01

301

Spontaneously breathing anesthetized patients with a laryngeal mask airway: positive end-expiratory pressure does not improve oxygen saturation.  

PubMed

Spontaneous ventilation is a popular mode of ventilation for patients with the laryngeal mask airway (LMA). Studies have shown, however, that spontaneous ventilation impairs gas exchange and that assisting or controlling ventilation results in higher oxygen saturation. Atelectasis during general anesthesia is a well described mechanism which impacts on gas exchange. Positive end-expiratory pressure (PEEP) increases the lung volume available for gas exchange. This study investigated whether the application of PEEP leads to an improvement of oxygen saturation in unassisted spontaneously breathing patients with a LMA. A total of 80 adult patients under general anesthesia were prospectively randomized into two groups. Both groups were left to breathe spontaneously. In group 1 the adjustable pressure limiting (APL) valve was opened resulting in zero end-expiratory pressure. In group 2 the valve was set to a PEEP of +7 cm H?O. Oxygen saturation was measured by pulse oxymetry at four different phases: pre-induction, after induction and insertion of the LMA, during maintenance and in recovery. The application of PEEP did not improve oxygen saturation. In both groups the mean oxygen saturation was similar (97.21.8% in group 1 versus 97.21.9% in group 2, p=0.941) during maintenance. No effect on oxygen saturation in recovery could be found either (96.01.8% in group 1 versus 96.12.0% in group 2, p=0.952) and hemodynamics were unaffected by the application of PEEP. The application of a PEEP of +7 cm H?O with a LMA under spontaneous ventilation cannot be recommended. Limitations of our study were the selection of healthy patients and omitting pre-oxygenation before induction which might have limited the development of atelectasis. In addition arterial partial pressure of oxygen (p(a)O?) measurements could have revealed subtle changes in oxygenation. PMID:20835692

Froessler, B; Brommundt, J; Anton, J; Khanduja, R; Kuhlen, R; Rossaint, R; Coburn, M

2010-09-11

302

Hydrogen vapor pressures from 4 to 30 K: a review. [67 references  

SciTech Connect

The following properties for the hydrogens from 4 to 30/sup 0/K are reviewed: liquid-gas and solid-gas vapor pressures, triple-point values, virial coefficients, liquid and solid densities, and heats of transformation. We have correlated these properties with as much consistency as the data allow. Empirical equations are given for virial coefficients and densities. Clausius-Clapeyron equations relate vapor pressure and temperature with the other properties. Data are frequently available with H/sub 2/ and D/sub 2/ and are sometimes available for HD and T/sub 2/. We have, therefore, estimated HT and DT values to complete the set. We have also reviewed work on binary H-D mixtures and have estimated the expected behavior for H-T and D-T systems.

Souers, P.C.; Briggs, C.K.; Pyper, J.W.; Tsugawa, R.T.

1977-02-18

303

Preliminary Heat Capacity and Vapor Pressure Measurements of 2D 4He on ZYX Graphite  

NASA Astrophysics Data System (ADS)

We report preliminary heat capacity and vapor pressure measurements of the first and second layers of 4He adsorbed on ZYX graphite. ZYX is known to have much better crystallinity than Grafoil, the most commonly-used exfoliated graphite substrate, such as a ten-times larger platelet size. This allows us to distinguish different phases in 2D 4He much more clearly and may provide qualitatively different insights into this system. We found a significantly asymmetric density-dependence of the heat-capacity peak associated with the sqrt{3}sqrt{3} phase formation comparing with that obtained with Grafoil. The 2nd-layer promotion density is determined as 11.80.3 nm-2 from the heat-capacity measurement of low density samples in the 2nd layer and vapor pressure measurement.

Nakamura, S.; Matsui, K.; Matsui, T.; Fukuyama, Hiroshi

2013-06-01

304

Observations of accelerated silicon carbide recession by oxidation at high water-vapor pressures  

SciTech Connect

A study of the exposure of SiC at 1,200 C and high water-vapor pressures (1.5 atm) has shown SiC recession rates that exceed what is predicted based on parabolic oxidation at water-vapor pressures of less than or equal to {approximately}1 atm. After exposure to these conditions, distinct silica-scale structures are observed; thick, porous, nonprotective cristobalite scales form above a thin, dense silica layer. The porous cristobalite thickens with exposure time, while the thickness of the underlying dense layer remains constant. These observations suggest a moving-boundary phenomenon that is controlled by the rapid conversion of dense vitreous silica to a porous, nonprotective crystalline SiO{sub 2}.

More, K.L.; Tortorelli, P.F.; Ferber, M.K.; Keiser, J.R.

2000-01-01

305

High-pressure vapor-liquid equilibrium for R-22 + ethanol and R-22 + ethanol + water  

Microsoft Academic Search

High-pressure vapor-liquid equilibrium (VLE) data for the systems CO + methanol at 313.05 K, CO + ethanol at 323.55, 325.15, and 333.35 K, R-22 (chlorodifluoromethane) + ethanol at 343.25, 361.45, and 382.45 K, and R-22 + ethanol + water at 351.55, 362.65, and 371.85 K are obtained using a circulation-type VLE apparatus. The apparatus is tested with measurements of the

Mohamed M. Elbaccouch; Michael B. Raymond; J. Richard Elliott

2000-01-01

306

High-power, high-pressure, discharge-heated copper vapor laser  

Microsoft Academic Search

A 40 mm diameter discharge-heated longitudinal copper vapor laser has been constructed. The laser performs most efficiently at a neon buffer gas pressure of 200-600 torr. The laser has produced over 20 W at 4 kHz as an oscillator and 30 W at 4 kHz and 20 W at 2 kHz (7.5 and 10 mJ\\/pulse) as an amplifier.

I. Smilanski; A. Kerman; L. A. Levin; G. Erez

1979-01-01

307

3D simulation of tungsten low-pressure chemical vapor deposition in contact holes  

Microsoft Academic Search

We present a new method for three-dimensional (3D) simulation of low-pressure chemical vapor deposition in arbitrary geometries using a segment-based topography discretization with triangles combined with the calculation of particle fluxes to the wafer surface. The simulation program is applied to tungsten LPCVD using the reduction of tungsten hexafluoride (WF6) by silane (SiH4). We found that an approach in which

E. Bar; J. Lorenz

1995-01-01

308

Versatile high-temperature high-pressure vapor cell design for electron beam excited laser studies  

Microsoft Academic Search

The design of a cell suitable for studying electron beam excited laser candidates at high temperatures such as organic dye and metal vapors is described. The cell is capable of handling temperatures up to 450 C and pressures from 10 to the -6th power torr to 15 atm. Details of both the high-temperature laser performance of Ar-N2 and the gain

G. Marowsky; R. Cordray; F. K. Tittel; W. L. Wilson

1978-01-01

309

Versatile high-temperature high-pressure vapor cell design for electron beam excited laser studies  

Microsoft Academic Search

The design of a cell suitable for studying electron beam excited laser candidates at high temperatures such as organic dye and metal vapors is described. The cell is capable of handling temperatures up to 450°C and pressures from 10⁻⁶ Torr to 15 atm. Details of both the high-temperature laser performance of Ar-N and the gain characteristics of the dye POPOP

G. Marowsky; R. Cordray; F. K. Tittel; W. L. Wilson

1978-01-01

310

Air Temperature and Vapor Pressure Changes Caused by Sprinkler Irrigation1  

Microsoft Academic Search

ABSTRACT The downwind,effect of evaporation from sprinkler spray was studied in the field to determine if air tem- perature and vapor pressure were changed enough,to influence plant growth and water use. Wet-bulb and dry-bulb temperature profiles were measured,upwind and at three distances downwind,from a sprinkler lateral before and during sprinkling. Wind-speed and direction were also measured. Air temperature generally was

R. A. Kohl; J. L. Wright

1974-01-01

311

Vapor pressure measurements of adsorbed neon on exfoliated graphite between 15 and 30 K  

Microsoft Academic Search

Vapor pressure measurements of neon adsorbed on bare Grafoil for coverages of 0.5, 0.75, 1.00, 1.25, 1.50, and 1.75 were made as a function of temperature in the range 1530 K using a standard volumetric method. Data plots of ln p vs. (1\\/T) were obtained for the coverages x of 1.25, 1.50, and 1.75 monolayers and there is an indication

E. Lerner; F. Hanono

1979-01-01

312

International Equations for the Saturation Properties of Ordinary Water Substance. Revised According to the International Temperature Scale of 1990. Addendum to J. Phys. Chem. Ref. Data 16, 893 (1987)  

Microsoft Academic Search

Consistent with the latest experimental data and the internationally recommended values for the critical parameters we published in 1987, compact and accurate correlation equations are given for the following properties on the saturation line of ordinary (light) water substance: vapor pressure, density, and enthalpy and entropy of both the saturated liquid and the saturated vapor. As an addendum to a

Wolfgang Wagner; A. Pruss

1993-01-01

313

Cycloheptane, cyclooctane and 1,3,5-cycloheptatriene. Low temperature thermal properties, vapor pressure and derived chemical thermodyamic properties  

Microsoft Academic Search

From determinations of the low temperature thermal properties and vapor pressure of cycloheptane, cyclooctane and 1,3,5-cycloheptatriene, values of the entropy in the liquid and vapor states and the heat of vaporization, all at 298.16°K, were obtained. These results and values of the heats of formation derivable from literature data were used to compute values of ..delta..Hf°, ..delta..Ff°, ..delta..Sf° and log

H. L. Finke; D. W. Scott; M. E. Gross; J. F. Messerly; G. Waddington

1956-01-01

314

Vapor pressures and enthalpies of sublimation of D-glucose, D-xylose, cellobiose, and levoglucosan  

SciTech Connect

The vapor pressures of {alpha}-D-glucose (or dextrose), D-xylose, D-cellobiose (or 4-{beta}-D-glucopyranosyl-D-glucopyranose), and levoglucosan (or 1,6-anhydro-{beta}-D-glucopyranose) have been measured using the Knudsen effusion technique, in the range of temperatures from 344 to 488 K. The measurements were all made in the solid sublimation regime, and enthalpies of sublimation were calculated from the Clausius-Claperon equation. The vapor pressures may be correlated by ln(P/Pa) = A {minus} B/(T/K), where A = 53.16, B = 23.382 ({+-}600) for D-glucose (395--406 K), A = 46.29 and B = 19,006 ({+-} 375) for D-xylose (370--395 K), and A = 70.30 and B = 36,264 ({+-} 5,220) for cellobiose (474--488 K). Levoglucosan displayed a solid phase transition at approximately 386 K, and its vapor pressure was affected accordingly. For this material, A = 38.96 and B = 15,049 ({+-} 123) in the temperature range 344--386 K and A = 31.19 and B = 12,066 ({+-} 709) in the temperature range 386--405 K.

Oja, V.; Suuberg, E.M. [Brown Univ., Providence, RI (United States). Div. of Engineering

1999-01-01

315

Vapor-liquid equilibrium data for fatty acids and fatty methyl esters at low pressures  

Microsoft Academic Search

ConclusionsThe experimental vapor-liquid equilibrium data obtained with a mixture of methyl esters, and a mixture of a fatty acid and\\u000a the corresponding methyl ester, were in agreement with calculated Raoults law data at a pressure of 4.00.2 mm. Hg.\\u000a \\u000a The system lauric acid-myristic acid was observed to be non-ideal or not obeying Raoults law at a pressure of 4.00.2 mm.

J. A. Monick; H. D. Allen; C. J. Marlies

1946-01-01

316

Influence of change in physical state on elastic nonlinear response in rock: Significance of effective pressure and water saturation  

SciTech Connect

We describe Young{close_quote}s mode resonant bar results obtained under effective pressure at two saturation states: dry and water saturated. We monitor primary manifestations of nonlinear response in these experiments: the harmonic content, the source extinction intensity, and fundamental resonant frequency shift. In addition, we describe the hysteretic behavior of the static pressure response, the linear modulus, and Q. Because we currently lack a complete theoretical description of nonlinear behavior under resonance at pressure, we provide relative measures of nonlinear response rather than absolute values. The rocks include Fontainebleau and Meule sandstones and Lavoux limestone. Dynamic strain levels range from 10{sup {minus}8} to 10{sup {minus}5} and frequencies range from 1 to 10 kHz. The elastic nonlinear response of each of the rocks is markedly different over the range of physical property states explored. The different responses are related to differences in mechanical response resulting from rock type, grain cement type, etc. In all of the samples studied, the change in resonant frequency as a function of excitation intensity is not measurable above approximately 10 MPa; however, harmonics are observed at larger effective pressure levels. Hysteresis in velocity and Q versus pressure vary considerably between the rocks. The effect of Q on the experiments is marked. When Q is low ({lt}10) as for some saturated samples, relative excitations must be large in order to induce equivalent dry sample strains.{copyright} 1997 American Geophysical Union

Zinszner, B. [Institut Francais du Petrole, Rueil Malmaison (France); Johnson, P.A. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico (United States)]|[Laboratoire dAcoustique Physique, Universite Pierre et Marie Curie, Paris; Rasolofosaon, P.N. [Institut Francais du Petrole, Rueil Malmaison (France)

1997-04-01

317

Vapor Pressure  

NSDL National Science Digital Library

This page is divided into several short sections, each focused on a specific topic such as evaporation or boiling point and each is accompanied by schematic illustrations of the process at the molecular level or a graph of the related variables.. Links to related topics are along the right hand side.

Nave, Carl R.

2010-01-01

318

Border control! Capillary pressure / saturation relationships in a diphasic flow in a random medium: Influence of the boundary conditions  

NASA Astrophysics Data System (ADS)

Solving problems involving biphasic flows in porous media, at a scale larger than the pore one, normally requires the use of relationships between pressure and saturation. These allow the closure of generalized Darcy flow models for two phases, commonly used in hydrology or large scale problems of diphasic flow in porous media. There are mathematical models which approximate experimental records with curve-fitting equations. The two most common models are the Brooks-Corey and van Genchten ones, they are used to complete a system of generalized Darcy equations. The purpose of the current study is the influence of the boundary conditions on the relationship between pressure and saturation. We perform numerical simulations of drainage experiments. Water is the wetting fluid and air is the non wetting fluid. The results highlight the fact that a filter which allows only water to flow at the exit face of the system modifies both the shape of the curve and the value of the residual saturation. The pressure of the models that are commonly used does not match with the pressure of real flows since there is no filter to cross, to flow from an elementary volume to another. Experiments performed in transparent Hele-Shaw cells exhibit the same features, showing the influence of the semi permeable boundary conditions on the pressure-saturation measures obtained. This effect corresponding to the formation of localized plugging clusters at the boundaries, is obtained in slow flow conditions, and is independent of any dynamic fingering, also known to affect such relations (1,2,3). Modeling flows in open media thus would require to use the central part of the curves pressure saturation where the effect of the boundaries is the least important, or to modify properly these relationships to extract the behavior unaffected by boundaries. References: (1) Two-phase flow: structure, upscaling, and consequences for macroscopic transport properties Renaud Toussaint ; Knut Jrgen Mly; Yves Mheust; Grunde Lvoll; Mihailo Jankov; Gerhard Schfer; Jean Schmittbuhl Vadose Zone Journal, 2012, 11 (3), pp. vzj2011.0123 (2) Lvoll, G., M. Jankov, K.J. Mly, R. Toussaint, J. Schmittbuhl, G. Schaefer and Y. Mheust, Influence of viscous fingering on dynamic saturation-pressure curves in porous media, Transport in Porous Media, 86, 1, 305-324, 2010 (3) Toussaint, R., G. Lvoll, Y. Mheust, K.J. Mly and J. Schmittbuhl, Influence of pore-scale disorder on viscous fingering during drainage, Europhys. Lett., 71, 583 (2005).

Fiorentino, Eve-Agns; Toussaint, Renaud; Moura, Marcel; Jankov, Mihailo; Schfer, Gerhard; Jrgen Mly, Knut

2013-04-01

319

Continuum percolation theory for pressuresaturation characteristics of fractal soils: extension to non-equilibrium  

Microsoft Academic Search

Systematic experimental deviations from theoretical predictions derived for water retention characteristics of fractal porous media have previously been interpreted in terms of continuum percolation theory (at low moisture contents, below the critical volume fraction of water, ?c capillary flow ceases). In other work, continuum percolation theory was applied to find the hydraulic conductivity as a function of saturation for saturations

A. G. Hunt

2004-01-01

320

Measurements of Capillary Pressure-Saturation Relationships for Silica Sands Using Light Transmission Visualization and a Rapid Pseudo Static Method  

NASA Astrophysics Data System (ADS)

Measurement of water saturation in porous media is essential for many types of studies including subsurface water flow, subsurface colloids transport and contaminant remediation to name a few. Water saturation (S) in porous media is dependent on the capillary pressure (Pc) which, in turn, depends on the interfacial tension between wetting and non-wetting phases, the pore size distribution of the porous material as well as the contact angle between fluids and porous media. Traditionally, measurements of the Pc-S relationship were carried out using pressure cells but these methods can be very time consuming. The objective of this research was to implement the innovative technique of light transmission visualization (LTV) to investigate the Pc-S relationships for porous media, and compare the results to an independent technique, namely a rapid pseudo-static automated method that was recently developed by Chen et al. Two dimensional (2-D) chambers constructed of two glass plates were packed with either 20/30 or 40/60 silica sand and then fully saturated with water. Images of the entire 2-D chambers were captured using a charge- coupled device (CCD) camera and analyzed pixel by pixel to determine air and water saturation in the porous media. Variable saturation of water and air across the height of the chamber was dictated by controlling the capillary pressure of the fluids. The primary drainage curve, main imbibition curve and secondary drainage curve were all measured, for the first time, using LTV and the results were compared to the results obtained by the rapid pseudo-static method. Overall, there was good agreement between the results of the two methods and variation in air entry pressure that was calculated based on Brooks-Cory model was within 2 cm for the sand sizes tested. Both techniques are capable of providing high spatial resolution data for the Pc-S relationships. Disclaimer This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.

Bob, M. M.; Brooks, M. C.; Chen, L.; Kibbey, T. C.; Wood, L.

2008-12-01

321

Critical mass flow rates through pressure relief valves  

Microsoft Academic Search

Simplified semi-empirical equations for the prediction of critical mass flow rates through pressure relief valves are presented. The fluid phases treated include hot and boiling liquids, liquid-vapor mixtures and saturated vapor. Predictive formulations are presented which express the critical mass flux explicitly in terms of reservoir temperature and pressure or reservoir quality, specific volumes of the liquid and vapor phases,

D. W. Sallet

1991-01-01

322

Control of hearing-aid saturated sound pressure level by frequency-shaped output compression limiting.  

PubMed

To fit a hearing aid successfully, it is important to set the Saturated Sound Pressure Level (SSPL) or Maximum Power Output (MPO) appropriately. The SSPL should be low enough to prevent sounds from being amplified to uncomfortable loudness, and yet high enough to maximize speech intelligibility and signal quality. To help attain an optimum SSPL setting, a novel output compression limiting scheme, with shapable MPO (ShaMPO), has been devised. In ShaMPO, the SSPL is shaped across frequencies in accordance with the individual user's loudness discomfort levels (LDLs). The contributions of different frequency regions to loudness are controlled by summing the amplified signal power relative to the LDLs across frequencies, and using this signal to control a wideband compressor. This scheme and a conventional output compression limiting (AGCo) scheme have been implemented in a digital hearing aid. Ten subjects, with moderately-severe to profound sensorineural hearing losses, participated in a study comparing speech intelligibility and listening comfort for the two schemes. Results showed that there were no significant differences in the speech perception scores between AGCo and ShaMPO, even when the speech was presented at 80 dBA, at which level both schemes were in compression much of the time. However, an examination of how subjects selected the SSPL for the two schemes revealed that, in many instances, AGCo would permit some sounds with compact spectra to be amplified above LDL, whereas ShaMPO would not. Thus the ShaMPO scheme can improve listening comfort for some intense sounds without a loss of speech intelligibility. In contrast, half the subjects found speech at 80 dBA to be uncomfortably loud when listening through their own aids. PMID:10207954

McDermott, H J; Dean, M R; Dillon, H

1999-01-01

323

The effect of thermal conduction upon pressure drawdown and buildup in fissured, vapor-dominated geothermal reservoirs  

Microsoft Academic Search

An analysis of steam-pressure behavior in a vapor-dominated geothermal reservoir with an immobile vaporizing liquid phase was presented by Moench and Atkinson (1977) at the Third Stanford Workshop on Geothermal Reservoir Engineering, and later expanded by Moench and Atkinson (1978). In that study a finite-difference model was used to demonstrate the effects of phase change in the reservoir upon pressure

Moench

1978-01-01

324

Rapid measurement of boiling points and vapor pressure of binary mixtures of short-chain triglycerides by TGA method  

Microsoft Academic Search

Thermogravimetric analysis (TGA), has been used to rapidly obtain data on the temperature dependence of vapor pressure (760, down to 20mmHg) and the boiling points for simple binary mixtures of tributyrin (C4:0), tricaproin (C6:0) and\\/or tricaprylin (C8:0). Vapor-pressure measurements were taken for binary mixtures of the aforementioned compounds as a function of mole fraction. Additional measurements of methyl esters of

J. W Goodrum; D. P Geller; S. A Lee

1998-01-01

325

Disjoining pressure and capillarity in the constrained vapor bubble heat transfer system.  

PubMed

Using the disjoining pressure concept in a seminal paper, Derjaguin, Nerpin and Churaev demonstrated that isothermal liquid flow in a very thin film on the walls of a capillary tube enhances the rate of evaporation of moisture by several times. The objective of this review is to present the evolution of the use of Churaev's seminal research in the development of the Constrained Vapor Bubble (CVB) heat transfer system. In this non-isothermal "wickless heat pipe", liquid and vapor flow results from gradients in the intermolecular force field, which depend on the disjoining pressure, capillarity and temperature. A Kelvin-Clapeyron model allowed the use of the disjoining pressure to be expanded to describe non-isothermal heat, mass and momentum transport processes. The intermolecular force field described by the convenient disjoining pressure model is the boundary condition for "suction" and stability at the leading edge of the evaporating curved flow field. As demonstrated by the non-isothermal results, applications that depend on the characteristics of the evaporating meniscus are legion. PMID:21470588

Chatterjee, Arya; Plawsky, Joel L; Wayner, Peter C

2011-03-21

326

Effect of water vapor pressure and frequency on fatigue behavior in 7017-T651 aluminium alloy plate  

SciTech Connect

The effect of water vapor pressure on fatigue crack growth in a commercial medium strength aluminium alloy is analyzed in this investigation, with particular emphasis on its relation to environmental exposure. Crack growth velocities were measured in high-purity water vapor environments with pressures ranging from 10{sup {minus}5}Pa to 1,300 Pa and testing frequencies between 1 Hz and 10 Hz. A detailed microscopic survey of the fracture surfaces was also performed. Different types of striations were found and correlated with water vapor exposures. Experimental results agree quite well with a hydrogen embrittlement model based on the proposals by R.P. Wei and co-workers.

Ruiz, J.; Elices, M. [Univ. Politecnica de Madrid (Spain). Dept. de Ciencia de Materiales

1997-01-01

327

High Pressure Oxidation of 4H-SiC in Nitric Acid Vapor  

NASA Astrophysics Data System (ADS)

High pressure chemical vapor oxidation of SiC in nitric acid vapor is reported. Higher growth rate at temperatures as low as 400 to 500 C has been achieved. The oxidation kinetics has been studied. It has been observed that the growth rate is strongly dependent on temperature, and the thickness of the oxide increases almost linearly with time within the error limits. X-ray photoelectron spectroscopy (XPS) measurement has been carried out to study the composition of the oxide. Room temperature electrical characterization (current--voltage and capacitance--voltage) has been carried out to estimate the oxide breakdown field strength, oxide charges, and interface state density. It is observed that prolonged oxidation or oxidation at higher temperature in acid ambient deteriorates the quality of oxide.

Selvi, K. Kalai; Sreenidhi, Turuvekere; DasGupta, Nandita; Ryssel, Heiner; Bauer, Anton

2011-10-01

328

High-pressure vapor-liquid equilibria in the propane-1-propanol system  

SciTech Connect

High-pressure isothermal vapor liquid equilibrium data were measured for the propane-1-propanol system at 81.6, 105.2, and 120.1 C in a static equilibrium cell with liquid-phase sampling by a piston-driven sampling rod and homogenizing the sample with a static jet mixer. The vapor phase was sampled by releasing it into an evacuated manifold, and the gas chromatograph was calibrated with a new variable volumetric device. Satisfactory modeling was achieved with the combined method using the UNIQUAC equation with equations of sate: the group contribution EOS, Peng-Robinson EOS, or the two-parameter Virial EOS. Differences between the measured and calculated vapor-phase mole fractions, however, were significant for the lower pressure regions of the 81.6 and 120.1 C isotherms. UNIQUAC parameters, hitherto unavailable, with fairly strong temperature dependence in the 81.6 to 120.1 C range are proposed for the system. The covariance matrix indicated a significant correlation among the parameters. The classical mixing rule interaction parameters required for the original Peng-Robinson EOS in the combined method were obtained using the direct method and were temperature-independent for the isotherms for which the propane was supercritical. The possibility of propane/1-propanol immiscibility was theoretically examined according to the criteria of Baker et al. The plots of Gibbs energy of mixing vs. phase mole fractions did not indicate liquid-phase splitting, but the inferences are EOS-dependent and must await visual confirmation. The authors earlier vapor-phase thermodynamic consistency test indicated the data for all three data sets not to be inconsistent.

Muehlbauer, A.L.; Raal, J.D. (Univ. of Natal, Durban (South Africa))

1993-04-01

329

Micromodel studies of three-fluid porous media systems: Pore-scale processes relating to capillary pressure-saturation relationships  

Microsoft Academic Search

An experimental approach to study physical processes affecting fluid behavior in three-fluid porous media systems was designed and implemented. These experiments were designed to provide quantitative evidence of important pore-scale displacement processes. A unique experimental approach using a two-dimensional synthetic porous medium (micromodel) and digital image analysis (DIA) enable both measurement of three-fluid capillary pressure-saturation relationships and analysis of fluid

W. E. Soll; M. A. Celia; J. L. Wilson

1993-01-01

330

Design of a diode-laser sensor to monitor water vapor in high-pressure combustion gases  

Microsoft Academic Search

The design of a diode-laser sensor to monitor water vapor in high-pressure combustion gases is described. The sensor, which employs a multiple-fixed-wavelength absorption strategy, has the potential to simultaneously monitor the water mole fraction and the temperature and pressure in high-pressure and high-temperature environments. The conventional scanned-wavelength strategy, employed in previous diode-laser sensors, is shown to be ill-suited for high-pressure

Venu Nagali; Ronald K. Hanson

1997-01-01

331

Thermodynamics of saturated and unsaturated ketones C 13 and C 18 and the energy of specific intermolecular interactions  

Microsoft Academic Search

P-T dependences of the saturated vapor of pseudoionone, hexahydropseudoionone, and saturated and unsaturated ketones C18 were studied using the statistical approach, and the enthalpies and entropies of its vaporization were calculated. The presence\\u000a of monomer forms of the molecules of these compounds was established by studying the unsaturated vapor pressure. It was demonstrated\\u000a that the role of isostructural methyl group

A. A. Baev; A. K. Baev

2011-01-01

332

Zno-based thin films synthesized by atmospheric pressure mist chemical vapor deposition  

Microsoft Academic Search

An atmospheric pressure mist chemical vapor deposition (mist-CVD) system has been developed to prepare zinc oxide (ZnO)-based thin films. This is a promising method for large-area deposition at low temperatures taking into account of its simplicity, inexpensiveness, and safety. Nominally pure ZnO, Al-doped n-type ZnO (ZnO:Al), and N-doped p-type ZnO (ZnO:N) thin films, as well as Zn1?xCdxO and Zn1?yMgyO alloy

J. G. Lu; T. Kawaharamura; H. Nishinaka; Y. Kamada; T. Ohshima; S. Fujita

2007-01-01

333

Preliminary results for the 5-20 cm wavelength opacity of ammonia pressure broadened by water vapor under jovian conditions  

NASA Astrophysics Data System (ADS)

At least one laboratory measurement study indicates that water vapor can efficiently broaden the 572 GHz rotational transition of ammonia [1], and this could be true for the inversion transitions of ammonia as well. Water vapor is the fourth most abundant constituent deep in the atmospheres of the jovian planets after hydrogen, helium, and methane [2]. While the broadening effects of the first three constituents on the ammonia absorption spectrum are now well characterized, it is critical to investigate any possible pressure broadening effects of water vapor on the ammonia absorption spectrum. Experimental investigation of the pressure broadening of the inversion lines of ammonia by water vapor in the microwave region is currently being performed. Over 500 measurements of the microwave properties of ammonia broadened by water vapor in a hydrogen/helium atmosphere have been conducted at pressures up to 100 bars and temperatures in the 375- 500 K range. On the basis of the data obtained in this work, an empirical estimation of the broadening of ammonia by water vapor has been obtained. These measurements will directly aid in the accurate interpretation of the observed microwave emission spectra of the jovian planets, and also improve retrievals of the atmospheric abundance of water vapor at Jupiter from the Juno microwave radiometer (MWR) measurements.

Devaraj, K.; Duong, D.; Steffes, P.

2011-10-01

334

Calculations of the equilibrium vapor pressure of water over adhering 50-200-nm spheres  

SciTech Connect

Treatments of condensation on aerosols generally assume the particles to be spherical implying that the condensate presents a positively curved surface to the surrounding vapor. In contrast, the region between two adhering spheres supports a pendular ring of condensation which may result in a condensate-vapor interface with negative curvature. According to the Kelvin equation, the equilibrium vapor pressure over such surfaces is depressed relative to a planar surface and therefore the substrate particle shows entirely different condensational characteristics than for an isolated sphere of similar size and composition to the adhering spheres. In this paper, literature results are utilized to develop general approaches to the calculation of the curvature of the pendular ring of condensation between two macroscopic spheres (radii > 10 nm) that may differ in size and composition. Results of calculations for specific cases are given for spheres of 50, 100, and 200 nm and for a range of condensate-substrate contact angles. Illustrative examples of critical supersaturations are calculated and dimensionless mean curvature graphs that can be used for computations of the critical supersaturations for adhering spheres of different size and composition are presented. These calculations indicate that even somewhat hydrophobic adhering spheres may be capable of activation as cloud condensation nuclei at the moderate supersaturations encountered in the atmosphere. 19 refs., 10 figs., 2 tabs.

Crouzet, Y.; Marlow, W.H. (Texas A M Univ., College Station, TX (United States))

1995-01-01

335

A vapor-pressure study of the systems formed by polonium with palladium and iridium  

SciTech Connect

Direct thermal vacuum synthesis shows that polonium vapor does not react with iridium when they are heated together to 1000/sup 0/C. Polonium vapor begins to be absorbed appreciably by palladium at 340-350/sup 0/C. The radiotensimetric method has been used in examining the thermal stabilities of polonium-palladium comounds, which has shown that there are three intermetallides PdPo, Pd/sub 2/Po, and Pd/sub 3/Po, which dissociate to release elemental polonium. The dissociation temperature increases as the polonium content of the compound decreases and is in the range 390-700/sup 0/C. The temperature dependence of the polonium vapor pressure in the dissociation is described by the following: PdPo log P /SUB Pa/ = (7.31 + or - 0.08) -- (4520 + or -40)/T, and at 460580/sup 0/C, ..delta..H = 86.3 + or - 0.7 kJ/mol; Pd/sub 2/Po log P /SUB Pa/ = (7.42 + or - 0.01) -- (6080 + or 10)/T at 725900/sup 0/C, ..delta..H = 116 + or - 0.2 kJ/mol; Pd/sub 3/Po log P /SUB Pa/ = (9.18 + or - 0.01) -- (8620 + or 1000/sup 0/C, ..delta..H = 164 + or - 1 kJ/mol. The properties of these compounds are compared with those of the corresponding tellurides and of the polonium-nickel and poloniumplatinum systems.

Abakumou, A.S.; Khokhlou, A.D.; Malysheu, M.L.; Reznikova, N.F.

1985-11-01

336

Compressional and shear waves in saturated rock during water-stream transition  

Microsoft Academic Search

Compressional and shear wave velocities were measured in water-filled Berea sandstone as a function of pore pressure, with a constant confining pressure of 300 bars. The measurements were made at room temperature, 145C, and 198C. At 145C, compressional velocity increased from vapor-saturated (low pore pressure) to liquid-saturated (high pore pressure) conditions, whereas shear wave velocity decreased. For compressional waves there

Hisao Ito; John De Vilbiss; Amos Nur

1979-01-01

337

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 July 1993--30 September 1993  

SciTech Connect

There is significant current interest in general area of coal pyrolysis, particularly with respect to comprehensive models of this complicated phenomenon. This interest derives from the central role of pyrolysis in all thermally driven coal conversion processes -- gasification, combustion, liquefaction, mild gasification, or thermal benefication. There remain several key data needs in these application areas. Among them is a need for more reliable correlation for prediction of vapor pressure of heavy, primary coal tars. Such information is important in design of all coal conversion processes, in which the volatility of tarry products is of major concern. Only very limited correlations exist, and these are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. Results of the literature survey are compiled. The experimental tasks have been concerned with setup and calibration.

Suuberg, E.M.; Oja, V.; Lilly, W.D.

1993-12-31

338

Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 January 1995--31 March 1995  

SciTech Connect

The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. Sophisticated general correlative approaches are slowly being developed, based upon group contribution methods, or based upon some key functional features of the molecules. These are as yet difficult to apply to coal tars. The detailed group contribution methods, in which fairly precise structural information is needed, do not lend themselves well for application to very complex, poorly characterized coal tars. The methods based upon more global types of characterizations have not yet dealt much with the question of oxygenated functional groups. In short, only very limited correlations exist, and these are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to testing the equipment for measurements by the Knudsen effusion method. The basic technique was described in the 9th Quarterly Report how the performance of the apparatus was checked by measuring, as a function of temperature, the vapor pressures of anthracene between 25 and 130{degrees}C, pyrene between 35 and 125{degrees}C, and coronene between 145 and 235{degrees}C.

Suuberg, E.M.; Oja, V.; Lilly, W.D.

1995-08-01

339

Computation of partial vapor pressures of aqueous volatile organic compound solutions. Final report, July 1993December 1995  

Microsoft Academic Search

A program is described for the evaluation of the partial vapor pressures of solution components dependent on the concentration in solution, total pressure, and temperature. The object of the program is to provide reliable values that represent the best estimate based on the large body of experimental data available in the literature. The basis of the estimate is the evaluation

P. E. Field; R. J. Combs; R. B. Knapp

1996-01-01

340

Measurements of the vapor pressures of difluoromethane, 1-chloro-1,2,2,2-tetrafluoroethane, and pentafluoroethane  

SciTech Connect

Information about vapor pressures is important initially to qualify potential candidates as working fluids in refrigeration machinery. Later, it is also very useful in calculating the thermodynamic properties necessary for the design of that machinery. The authors present new measurements of the vapor pressures of difluoromethane (R32) from 235 to 265 K, of 1-chloro-1, 2, 2, 2-tetrafluoroethane (R124) from 220 to 286 K, and of pentafluoroethane (R125) from 218 to 286 K. Measurements were made in two ebulliometers, one of glass and one of metal. Overall, pressures ranged from 13 to about 950 kPa. The authors also present vapor pressures of R125, calculated via thermodynamic relationships, for temperature down to 170 K (2.3 kPa). They study the azeotropic mixture of R125 with chloropentafluoroethane (R115), and they correct the data for a small R115 impurity.

Weber, L.A.; Silva, A.M. (National Inst. of Standards and Technology, Gaithersburg, MD (United States). Chemical Science and Technology Lab.)

1994-10-01

341

Treatment of multiple eruptive vellus hair cysts with carbon dioxide laser vaporization and manual lateral pressure.  

PubMed

Treatment of eruptive vellus hair cysts (EVHC) is often unsatisfactory. Laser treatment has been described as an adequate treatment in a few reports. Pulsed carbon dioxide (CO(2)) laser has been used effectively for facial EVHC and erbium:yttrium-aluminium-garnet laser has been used to treat truncal EVHC with variable outcomes. We report our experience with CO(2) laser and lateral manual pressure to extract the cysts as an effective treatment in two cases of EVHC. Good cosmetic results were obtained in both cases. No lesion recurrence was observed after a follow-up of 10 years in the first case and 3 years in the second one. CO(2) laser vaporization and further extraction of cysts by manual lateral pressure might be an effective method to treat EVHC, achieving good cosmetic results and no recurrence. PMID:19663855

Fernndez-Torres, R; Del Pozo, J; Castieiras, I; Sacristn, F; Mazaira, M; Fonseca, E

2009-07-29

342

Atmospheric Pressure Plasma Enhanced Chemical Vapor Deposition of Borophosphosilicate Glass Films  

NASA Astrophysics Data System (ADS)

Borophosphosilicate glass (BPSG) films have been grown on silicon wafers by plasma enhanced chemical vapor deposition at atmospheric pressure (AP-PECVD). Tetraethoxysilane (TEOS), triethylborate (TEB), and trimethylphosphite (TMPI) were adopted as precursors, and argon and oxygen were respectively used as the carrier and reactive gases to produce stable plasma at atmospheric pressure. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and refractive index and stress measurements were employed to characterize BPSG films. The effects of input radio-frequency (RF) power and precursor (TEB and TMPI) flow rate on deposition rate were studied. Results indicated that the deposition rate of BPSG films increases with increasing input RF power and precursor flow rate. In addition, reactive gaseous species were detected by optical emission spectroscopy to reveal the possible reaction process of BPSG film deposition.

Yin, Minghui; Zhao, Lingli; Xu, Xiangyu; Wang, Shouguo

2008-03-01

343

Detection and measurement of sulfur mustard (HD) offgassing from the weanling pig following exposure to saturated HD vapor. Technical report, September-October 1994  

SciTech Connect

Sulfur mustard (HD) is a chemical warfare agent for which there is neither antidote nor adequate therapeutic protection. Animal models are employed to investigate mechanisms of injury and to evaluate protective measures against HD exposure. Researchers whose experiments involve cutaneous application of HD vapor to animals benefit from the detection and quantitation of HD at the exposed site. The ability to detect and quantify HD enables the researcher to follow safe procedures in handling skin samples. We have designed an experimental procedure to measure HD offgassing from animal models. A Minicams(R), which is a portable gas chromatograph (GC) equipped with a flame photometric detector (FPD) and with online sorbent collection and desorption, was used to monitor the HD concentration. Confirming measurements were made using a two-step process that trapped HD on a Tenax sorbent offline and then transferred the sample by means of an ACEM 900 to a OC equipped with either FPD or a mass spectrometer (MS). We collected data from six experiments in which weanling pigs were exposed to saturated HD vapor via vapor caps containing 10 micro of HD. HD concentration was measured in time-weighted-average (TWA) units at a specific HD application site. The currently recommended exposure value for HD is 3 ng/l, 1 TWA unit. In five of the six experiments, Minicams HD concentration values were less than 0.5 TWA, 2 hours postexposure, and in one of the experiments, TWA Minicams concentration was less than 0.5 TWA, 5 hours post-exposure. OCIMS detection was used in three of the experiments to confirm Minicams data and to provide greater sensitivity and selectivity at 0.1 TWA. GC/MS data confirmed that HD concentrations fell below 0.1 TWA in less than S hours for a specific site.

Logan, T.P.; Graham, J.S.; Martin, J.L.; Zallnick, J.E.; Jakubowski, E.M.

1997-11-01

344

Saturated defect densities of hydrogenated amorphous silicon grown by hot-wire chemical vapor deposition at rates up to 150 Aa/s  

SciTech Connect

Hydrogenated amorphous-silicon (a-Si:H) is grown by hot-wire chemical vapor deposition (HWCVD) at deposition rates (R{sub d}) exceeding 140 Aa/s ({similar_to}0.8 {mu}m/min). These high rates are achieved by using multiple filaments and deposition conditions different than those used to produce our standard 20 Aa/s material. With proper deposition parameter optimization, an AM1.5 photo-to-dark-conductivity ratio of 10{sup 5} is maintained at an R{sub d} up to 130 Aa/s, beyond which it decreases. In addition, the first saturated defect densities of high R{sub d} a-Si:H films are presented. These saturated defected densities are similar to those of the best HWCVD films deposited at 5{endash}8 Aa/s, and are invariant with R{sub d} up to 130 Aa/s. {copyright} 2001 American Institute of Physics.

Mahan, A. H.; Xu, Y.; Nelson, B. P.; Crandall, R. S.; Cohen, J. D.; Palinginis, K. C.; Gallagher, A. C.

2001-06-11

345

PARAMETER ESTIMATION OF TWO-FLUID CAPILLARY PRESSURE-SATURATION AND PERMEABILITY FUNCTIONS  

EPA Science Inventory

Capillary pressure and permeability functions are crucial to the quantitative description of subsurface flow and transport. Earlier work has demonstrated the feasibility of using the inverse parameter estimation approach in determining these functions if both capillary pressure ...

346

Density, vapor pressure, solubility, and viscosity for water + lithium bromide + lithium nitrate + 1,3-propanediol  

SciTech Connect

Four physical properties (solubility, vapor pressure, density, and viscosity) of water + lithium bromide + lithium nitrate + 1,3-propanediol (LiBr/LiNO{sub 3} mole ratio = 4, (LiBr + LiNO{sub 3})/HO(CH{sub 2}){sub 3}OH mass ratio = 3.5) were measured. The system, a possible working fluid for an absorption heat pump, mainly consists of absorbent (LiBr + LiNO{sub 3} + HO(CH{sub 2}){sub 3}OH) and refrigerant (H{sub 2}O). Solubilities were measured by the visual polythermal method in the temperature range (285.55 to 346.65) K and in the absorbent concentration range (68.0 to 75.0) mass %. Vapor pressures were measured by the boiling point method in the temperature range (325.35 to 395.15) K and in the absorbent concentration range (46.0 to 69.6) mass %. Densities and viscosities were measured by a set of hydrometers and viscometers, respectively, in the temperature range (283.15 to 343.15) K and in the absorbent concentration range (24.3 to 70.3) mass %. The measured values were correlated.

Park, Y.; Kim, J.S.; Lee, H. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering; Yu, S.I. [Rinnai Korea, Taejon (Korea, Republic of). R and D Lab.

1997-01-01

347

High Vapor Pressure Perfluorocarbons Cause Vesicle Fusion and Changes in Membrane Packing  

PubMed Central

Perfluorocarbons (PFCs) hold great promise for biomedical applications. However, relatively little is known about the impact of these chemicals on membranes. We used unilamellar vesicles to explore the effects of PFCs on membrane packing and vesicle stability. Four clinically relevant PFCs with varying vapor pressures (PP1, 294 mbar; PP2, 141 mbar; PP4, 9.6 mbar; and PP9, 2.9 mbar) were examined. Microscopy imaging and spectroscopic measurements suggest that PFCs, especially those with high vapor pressures, lead to vesicle fusion within hours. Upon exposure to PP1 and PP2 for 72 h, vesicles retained a spherical shape, but the size changed from ?200 nm to ?2040 ?m. In addition, membrane packing underwent marked changes during this timeframe. A significant decrease in water content in the lipid polar headgroup regions occurred during the first 12-h exposure to PFCs, followed by a steady increase in water content over time. Possible mechanisms were proposed to explain these dramatic structural changes. The finding that chemically inert PFCs exhibited fusogenic activity and marked changes in membrane surface packing is novel, and should be considered when using PFCs for biomedical applications.

Venegas, Berenice; Wolfson, Marla R.; Cooke, Peter H.; Chong, Parkson Lee-Gau

2008-01-01

348

Satellite Derived Seasonal and Diurnal Variations of Cloudiness Over the Gulf Stream Locale and its Relationship to Saturation Pressure Differences.  

NASA Astrophysics Data System (ADS)

Fields of cloudiness derived from the Geostationary Operational Environmental Satellite (GOES) Visible Infrared Spin Scan Radiometer (VISSR) Atmospheric Sounder (VAS) are analyzed over the Gulf Stream region to investigate the seasonal, diurnal and geographical variations from a climatological perspective. The Gulf Stream is a warm current of water which flows south to north along the East Coast of the United States and provides conditions conducive for the development of cloudiness. The Gulf Stream Locale in this dissertation refers to an area which includes the United States mid-Atlantic coastal states, the extent of the Gulf Stream immediately offshore and portions of the Sargasso Sea. Clouds over the Gulf Stream region are found approximately three-quarters of the time between 1985-1993. However, large seasonal variations in the frequency of cloudiness exist. These seasonal variations show a distinct relationship to gradients in sea surface temperature. Diurnal variations are found during both the summer and winter. During the summer, satellite observations indicate a maximum in the frequency of low cloudiness during the day and a minimum at night over land. In addition, high cloudiness is found to increase significantly late in the afternoon and evening in response to prevalent convective activity. During winter, when convective activity is suppressed, there is less detectable response of the atmosphere to the 24-hour solar cycle manifest in the diurnal variations of clouds. A comparison between GOES-VAS observations and surface determinations of cloud cover indicate the satellite can be useful in estimating composite fractional cloudiness. Histograms of satellite determinations of effective cloud amount and cloud top pressures are investigated for patterns which can reveal the surface observations of cloudiness. In general, this method of grouping cloud top pressures and effective cloud amounts results in either complementing or supplementing the ground observation of cloud cover. Saturation pressure difference, a conserved variable which provides a measure of parcel subsaturation, is derived from radiosonde soundings and model analyses. A comparison of the mean saturation pressure difference in three layers of the atmosphere (representing low, mid and high cloudiness) to surface observations of cloudiness is conducted to investigate their relationship. Results indicate that the saturation pressure difference concept is a useful tool and can provide reasonable estimates of cloud fraction. The saturation pressure differences are also useful in estimating whether or not precipitation is occurring.

Alliss, Randall Jamil

1995-01-01

349

Preliminary design: duplex tube low-pressure saturated steam generator for large LMFBR plant. Final report  

Microsoft Academic Search

A preliminary design was completed for a steam generator which is applicable to a four loop LMFBR plant of 1000 MWe gross output employing dry and saturated steam conditions. Two steam generators of 364 MWt thermal capacity would be in each loop. The steam generator is a straight, duplex tube design with a shell bellows for thermal expansion and a

1979-01-01

350

What is the significance of pore pressure in a saturated shale layer?  

Microsoft Academic Search

Electrostatic interactions, associated with negatively charged surfaces of clay minerals, produce a so-called disjoining pressure when diffuse layers overlap, i.e., at low porosity. Disjoining pressure is the pressure difference between the water in the clay pore space and that in a bulk solution at the same depth. Another widely used concept in clay-rocks is the swelling pressure. It corresponds in

J. Gonalvs; P. Rousseau-Gueutin; G. de Marsily; P. Cosenza; S. Violette

2010-01-01

351

What is the significance of pore pressure in a saturated shale layer?  

Microsoft Academic Search

Electrostatic interactions, associated with negatively charged surfaces of clay minerals, produce a so-called ``disjoining pressure'' when diffuse layers overlap, i.e., at low porosity. Disjoining pressure is the pressure difference between the water in the clay pore space and that in a bulk solution at the same depth. Another widely used concept in clay-rocks is the ``swelling pressure.'' It corresponds in

J. Gonalvs; P. Rousseau-Gueutin; G. de Marsily; P. Cosenza; S. Violette

2010-01-01

352

Correction factors for saturation effects in white light and laser absorption spectroscopy for application to low pressure plasmas  

NASA Astrophysics Data System (ADS)

In white light absorption spectroscopy, the broadening of the absorption signal due to the apparatus profile of the spectrometer may lead to an underestimation of the determined density as one measures an apparent optical depth. This is in particular true for high optical depth where saturation effects of the transmitted intensity occur. Provided that the line profile of the absorption line is known, the apparent optical depth effect can be accounted for by introducing a correction factor. The impact of the saturation and the approach of considering the effect are demonstrated for argon and indium lines in low pressure plasmas where correction factors of one order of magnitude or even higher are reached very easily. For the indium line, the hyperfine splitting has been taken into account. In laser absorption, the line profile is resolved. However, the weak but rather broad background emission of the laser diode can cause a saturation signal at the photo diode resulting also in an underestimation of the density obtained from the analysis. It is shown that this can be taken into account by fitting the theoretical line profile to the measured absorption signal which yields also a correction factor. The method is introduced and demonstrated at the example of the cesium resonance line including the hyperfine splitting. Typical correction factors around two are obtained for the cesium ground state density at conditions of a low pressure negative hydrogen ion source in which cesium is evaporated to enhance the negative ion production.

Briefi, S.; Wimmer, C.; Fantz, U.

2012-05-01

353

Predicting temperature-dependent solid vapor pressures of explosives and related compounds using a quantum mechanical continuum solvation model.  

PubMed

Temperature-dependent vapor pressures of solid explosives and their byproducts are calculated to an accuracy of 0.32 log units using a modified form of the conductor-like screening model for real solvents (COSMO-RS). Accurate predictions for solids within COSMO-RS require correction for the free energy of fusion as well as other effects such as van der Waals interactions. Limited experimental data on explosives is available to determine these corrections, and thus we have extended the COSMO-RS model by introducing a quantitative structure-property relationship to estimate a lumped correction factor using only information from standard quantum chemistry calculations. This modification improves the COSMO-RS estimate of ambient vapor pressure by more than 1 order of magnitude for a range of nitrogen-rich explosives and their derivatives, bringing the theoretical predictions to within typical experimental error bars for vapor pressure measurements. The estimated temperature dependence of these vapor pressures also agrees well with available experimental data, which is particularly important for estimating environmental transport and gas evolution for buried explosives or environmentally contaminated locations. This technique is then used to predict vapor pressures for a number of explosives and degradation products for which experimental data is not readily available. PMID:23398143

Alnemrat, Sufian; Hooper, Joseph P

2013-02-21

354

A unified equation for calculating methane vapor pressures in the CH 4-H 2O system with measured Raman shifts  

NASA Astrophysics Data System (ADS)

A unified equation has been derived by using all available data for calculating methane vapor pressures with measured Raman shifts of C-H symmetric stretching band ( ?1) in the vapor 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 vapor phase of CH 4-H 2O mixtures prepared in a high-pressure optical cell were also measured at temperatures between room temperature and 200 C, and pressures up to 37 MPa. The results show that the CH 4?1 band position shifts to higher wavenumber as temperature increases. We also demonstrated that this Raman band shift is a simple function of methane vapor density, and, therefore, when combined with equation of state of methane, methane vapor pressures in the sample fluids at elevated temperatures can be calculated from measured Raman peak positions. This method can be applied to determine the pressure of CH 4-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.

Lu, Wanjun; Chou, I.-Ming; Burruss, R. C.; Song, Yucai

2007-08-01

355

AA Parametric Model for Predicting Relative Permeability-Saturation-Capillary Pressure Relationships of Oil?Water Systems in Porous Media with Mixed Wettability  

SciTech Connect

A parametric two-phase, oil-water relative permeability/capillary pressure model for petroleum engineering and environmental applications is developed for porous media in which the smaller pores are strongly water-wet and the larger pores tend to be intermediate- or oil-wet. A saturation index, which can vary from 0 to 1, is used to distinguish those pores that are strongly water-wet from those that have intermediate- or oil-wet characteristics. The capillary pressure submodel is capable of describing main-drainage and hysteretic saturation-path saturations for positive and negative oil-water capillary pressures. At high oil-water capillary pressures, an asymptote is approached as the water saturation approaches the residual water saturation. At low oil-water capillary pressures (i.e., negative), another asymptote is approached as the oil saturation approaches the residual oil saturation. Hysteresis in capillary pressure relations, including water entrapment, is modeled. Relative permeabilities are predicted using parameters that describe main drainage capillary pressure relations and accounting for how water and oil are distributed throughout the pore spaces of a porous medium with mixed wettability. The capillary pressure submodel is tested against published experimental data, and an example of how to use the relative permeability/capillary pressure model for a hypothetical saturation-path scenario involving several imbibition and drainage paths is given. Features of the model are also explained. Results suggest that the proposed model is capable of predicting relative permeability/capillary pressure characteristics of porous media mixed wettability.

Lenhard, Robert J. (INEEL); Oostrom, Mart (BATTELLE (PACIFIC NW LAB))

1998-01-01

356

Semiconductor laser-based measurements of quench rates in an atmospheric pressure plasma by using saturated-fluorescence spectroscopy.  

PubMed

Plasma diagnostics based on saturated fluorescence and absorption spectroscopy with a semiconductor (diode) laser are developed to probe the 4s(3)P(1) ? 4p(3)D(2) transition (8425 A) of argon in an atmospheric pressure plasma produced by an inductively coupled plasma torch. Spatially resolved measurements of saturation intensity, nonradiative collisional transfer (quench) rate, and fluorescence yield (Stern-Volmer factor) are inferred from variations of spectral profile characteristics (line shape, line-center value, and frequency-integrated signal) with laser intensity. The results obtained by using fluorescence and absorption spectroscopy are mutually consistent in the analytical region 10 mm above the induction coil. The measured quench rates compare favorably with computed rates from a multilevel collisional radiative model that assumes a suprathermal electron population relative to the local thermodynamic equilibrium value at the kinetic temperature. PMID:20802772

Baer, D S; Hanson, R K

1993-02-20

357

Apparatus for determination of vapor pressures at ambient temperatures employing a Knudsen effusion cell and quartz crystal microbalance  

Microsoft Academic Search

We describe an apparatus for the measurement of vapor pressures of solids or liquids at ambient temperatures (260 K < T < 350 K) demonstrated to operate over a pressure range of 10-2-10-6 Torr (1-10-4 Pa), but capable of being extended to lower pressures by at least an order of magnitude. It employs a Knudsen cell to produce an effusive

Andrew Freedman; Paul L. Kebabian; Ziman Li; Wade A. Robinson; Joda C. Wormhoudt

2008-01-01

358

D0 Silicon Upgrade: Vapor Pressure Thermometry System Near LN2 Subcooler  

SciTech Connect

Fermi National Accelerator Laboratory (Fermilab) is in the process of upgrading its detectors. Among these upgrades is the need for more transfer lines containing both liquid nitrogen and helium gas. These two fluids are used to provide the necessary operating cryogenic temperatures for the various detectors, such as the Visible Light Photon Counter (VLPC) and the solenoid inside the detector's calorimeter. With additional piping, it is important to monitor the temperatures to assure that the detectors can operate correctly. This can be done two ways. The first method is to use a Resistance Temperature Device, called a RTD, which is made using either a carbon resistor or a platinum resistor and measures the temperature based on resistance. The second method is to use a vapor-pressure thermometry system. This design will focus on the second method. A nitrogen Vapor Pressure Thermometer (VPT) system is designed to determine the temperature of the liquid nitrogen (LN{sub 2}) supply line, after exiting the LN{sub 2} subcooler, inside the D-Zero Assembly Hall. The operating temperature range is designed from 77 to 300 Kelvin with an initial charge pressure of 100 psia. A cylindrical bulb with a 0.1875-inch diameter and 0.625-inch length allows for minimum cold and warm 1/4-inch O.D. SS 304L tubing lengths, 12-inch and 18-inch respectively, and maintains a liquid level of 50% inside the bulb during cold operation. The amount of nitrogen needed to fill the cylindrical bulb approximately half full is 0.149 grams. In order to conform to the conventional cold volume and warm volume VPT systems, we need to enlarge the existing 1/2-inch x 2-inch SCH. 10 LN{sub 2} supply line over a one foot section to 1-inch x 3-inch SCH. 10 piping.

Kuwazaki, Andrew; /Fermilab

1996-07-01

359

Saturated liquid densities and bubble-point pressures of the binary HFC 152a+HCFC 142b system  

NASA Astrophysics Data System (ADS)

Forty-eight sets of the saturated liquid densities and bubble-point pressures of the binary HFC 152a + HCFC 142b system were measured with a magnetic densimeter coupled with a variable-volume cell. The measurements obtained at four compositions, 20, 40, 60, and 80 wt%, of HFC 152a cover a range of temperatures from 280 to 400 K. The experimental uncertainties in temperature, pressure, density, and composition were estimated to be within 15mK, 20kPa, 0.2%, and between -0.14 and 0.01 wt% HFC 152a (-0.01 and + 0.14 wt% HCFC 142b), respectively. The purities of the samples were 99.9 wt% for HFC 152a and 99.8 wt% for HCFC 142b. A binary interaction parameter, k ij , in the Peng-Robinson equation of state was determined as a function of temperature for representing the bubble-point pressures. On the other hand, two constant binary-interaction parameters, k ij and l ij , were introduced into the mixing rule of the Hankinson-Brobst-Thomson equation for representing the saturated liquid densities.

Maezawa, Y.; Widiatmo, J. V.; Sato, H.; Watanabe, K.

1991-11-01

360

The separation and characterization of a hydrogen getter product mixture: Part 2, measurement of product vapor pressures  

SciTech Connect

HCPB is the acronym of an organic hydrogen getter compound used in weapon systems. When this material scavenges hydrogen by reacting with it, a number of compounds are formed, each of which is more volatile than HCPB. It is desirable to know the vapor pressure of these products in order to assess their migration potential within the weapon. In this study, individual compounds from a reacted HCPB mixture were isolated and their vapor pressures were measured. Three of the four fractions examined with a modified capacitance manometer were found to have vapor pressures under 1 mtorr; the fourth was measured at 92 +- 15 mtorr. An attempt was made to obtain boiling point data on the two liquid components of the getter mixture, but they decomposed before reaching their boiling points.

Fircish, D.W.; Shell, T.R.

1987-06-04

361

High-pressure vapor-liquid equilibria of two binary systems: Carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone  

SciTech Connect

Vapor-liquid equilibria for carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone were measured using an apparatus based on a static-analytic method with in situ samplings. P, T, x, y measurements were made at pressures up to 22 MPa. The carbon dioxide + cyclohexanol system was studied at 433 and 473 K, and carbon dioxide + cyclohexanone, at 433 and 473 K. The results are correlated by the Redlich-Kwong-Soave and Peng and Robinson equations and several mixing rules. The best fittings are obtained with the Peng-Robinson equation of state and a two-parameter mixing rule, i.e., within 1.1% for both pressures and vapor mole fractions on the carbon dioxide + cyclohexanone system and within 1.9% for pressures and 2.9% for vapor mole fractions on the carbon dioxide + cyclohexanol system. More recent equations by Patel and Teja and Salim and Trebble show no significant advantages.

Laugier, S. [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France); Richon, D. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)

1997-01-01

362

Non-canonical mass laws in equilibrium isotopic fractionations: Evidence from the vapor pressure isotope effect of SF6  

NASA Astrophysics Data System (ADS)

We report experimental observations of the vapor pressure isotope effect, including 33S/32S and 34S/32S ratios, for SF6 ice between 137 and 173 K. The temporal evolution of observed fractionations, mass-balance of reactants and products, and reversal of the fractionation at one temperature (155 K) are consistent with a subset of our experiments having reached or closely approached thermodynamic equilibrium. That equilibrium involves a reversed vapor pressure isotope effect; i.e., vapor is between 2 and 3 higher in 34S/32S than co-existing ice, with the difference increasing with decreasing temperature. At the explored temperatures, the apparent equilibrium fractionation of 33S/32S ratios is 0.551 0.010 times that for 34S/32S ratioshigher than the canonical ratio expected for mass dependent thermodynamic fractionations (0.515). Two experiments examining exchange between adsorbed and vapor SF6 suggest the sorbate-vapor fractionation at 180-188 K is similar to that for ice-vapor at 150 K. In contrast, the liquid-vapor fractionation at 228-300 K is negligibly small (0.1 for 34S/32S; the mass law is ill defined due to the low amplitude of fractionation). We hypothesize that the observed vapor pressure isotope for SF6 ice and sorbate is controlled by commonly understood effects of isotopic substitution on vibrational energies of molecules, but leads to both an exotic mass law and reversed fractionation due to the competition between isotope effects on intramolecular vibrations, which promote heavy isotope enrichment in vapor, and isotope effects on intermolecular (lattice) vibrations, which promote heavy isotope enrichment in ice. This explanation implies that a variety of naturally important compounds having diverse modes of vibration (i.e., varying greatly in frequency and particularly, reduced mass) could potentially exhibit similarly non-canonical mass laws for S and O isotope fractionations. We examined this hypothesis using a density function model of SF6 vapor and lattice dynamic model of SF6(ice). These models support the direction of the measured vapor pressure isotope effect, but do not quantitatively agree with the magnitude of the fractionation and poorly match the phonon spectrum of SF6 ice. A strict test of our hypothesis must await a more sophisticated model of the isotopic dependence of the phonon spectrum of SF6 ice.

Eiler, John; Cartigny, Pierre; Hofmann, Amy E.; Piasecki, Alison

2013-04-01

363

Frictional behavior of diamondlike carbon films in vacuum and under varying water vapor pressure.  

SciTech Connect

In this study, we investigated the frictional behavior of both hydrogenated and hydrogen-free diamondlike carbon (DLC) films in high vacuum (10{sup -6} Pa) at room temperature. Water was also introduced into the vacuum chamber to elucidate its effects on DLC film tribology. The hydrogen-free DLC (also referred to as tetrahedral amorphous carbon, or ta-C) was produced by an arc-PVD process, and the highly hydrogenated DLC was produced by plasma-enhanced chemical-vapor deposition. Tribological measurements of these films were made with a pin-on-disc machine with coated steel balls and coated steel discs in matched pairs under a 1 N load. The ball/disk pairs were rotated at sliding speeds in the range of 0.025-0.075 m/s. In vacuum, the steady-state friction coefficient of ta-C was of the order of 0.6 and the wear was severe, whereas for the highly hydrogenated film, friction was below 0.01, and in an optical microscope no wear could be detected. Adding water vapor to the sliding ta-C system in a vacuum chamber caused friction to decrease monotonically from 0.6 to {approx}0.05. In contrast, adding water vapor to the sliding DLC system caused the friction to increase linearly with pressure from 0.01 to 0.07. The results illustrate the importance of taking into account environmental conditions, especially the presence of water, when DLC films are being considered for a given application.

Andersson, J.; Erck, R. A.; Erdemir, A.

2002-03-25

364

Germanium determination by flame atomic absorption spectrometry: an increased vapor pressure-chloride generation system.  

PubMed

A new chloride generation system was designed for the direct, sensitive, rapid and accurate determination of the total germanium in complex matrices. It was aimed to improve the detection limit of chloride generation technique by increasing the vapor pressure of germanium tetrachloride (GeCl(4)). In order to do so, a novel joint vapor production and gas-liquid separation unit equipped with a home-made oven was incorporated to an ordinary nitrous oxide-acetylene flame atomic absorption spectrometer. Several variables such as reaction time, temperature and acid concentration have been investigated. The linear range for germanium determination was 0.1-10 ng mL(-1) for 1 mL sampling volume with a detection limit (3s) of 0.01 ng mL(-1). The relative standard deviation (RSD) was 2.4% for nine replicates of a 1 ng mL(-1) germanium solution. The method was validated by the analysis of one non-certified and two certified geochemical reference materials, respectively, CRM GSJ-JR-2 (Rhyolite), and GSJ-JR-1 (Rhyolite), and GBW 07107 (Chinese Rock). Selectivity of the method was investigated for Cd(2+), Co(2+), Cu(2+), Fe(3+), Ga(3+), Hg(2+), Ni(2+), Pb(2+), Sn(2+), and Zn(2+) ions and ionic species of As(III), Sb(III), Te(IV), and Se(IV). PMID:21315908

Kaya, Murat; Volkan, Mrvet

2010-12-25

365

Vapor pressure and boiling point elevation of slash pine black liquors: Predictive models with statistical approach  

SciTech Connect

Vapor-liquid equilibria and boiling point elevation of slash pine kraft black liquors over a wide range of solid concentrations (up to 85% solids) has been studied. The liquors are from a statistically designed pulping experiment for pulping slash pine in a pilot scale digester with four cooking variables of effective alkali, sulfidity, cooking time, and cooking temperature. It was found that boiling point elevation of black liquors is pressure dependent, and this dependency is more significant at higher solids concentrations. The boiling point elevation data at different solids contents (at a fixed pressure) were correlated to the dissolved solids (S/(1 {minus} S)) in black liquor. Due to the solubility limit of some of the salts in black liquor, a change in the slope of the boiling point elevation as a function of the dissolved solids was observed at a concentration of around 65% solids. An empirical method was developed to describe the boiling point elevation of each liquor as a function of pressure and solids mass fraction. The boiling point elevation of slash pine black liquors was correlated quantitatively to the pulping variables, using different statistical procedures. These predictive models can be applied to determine the boiling point rise (and boiling point) of slash pine black liquors at processing conditions from the knowledge of pulping variables. The results are presented, and their utility is discussed.

Zaman, A.A.; McNally, T.W.; Fricke, A.L. [Univ. of Florida, Gainesville, FL (United States)

1998-01-01

366

Tropospheric Water Vapor Profiles Retrieved from Pressure-Broadened Emission Spectra at 22 GHz  

NASA Astrophysics Data System (ADS)

The authors present the analysis and the evaluation of the retrieval of tropospheric water vapor profiles from pressure-broadened emission spectra at 22 GHz measured with a ground-based microwave spectroradiometer. The spectra have a bandwidth of 1 GHz with a resolution of 20 MHz and are centered at 22.235 GHz. Because of the small bandwidth, the retrieval is insensitive to clouds and measurements are possible under almost all nonprecipitating weather conditions. The retrieved profiles are evaluated with a set of 200 coincident balloon soundings with RS92 sensors. The correlation coefficient between the microwave retrievals and the RS92 measurements lies above 0.7 km, up to 8 km, and the retrievals show a wet bias compared to RS92 of 10% at 2 km, increasing to 30% at 6 km.

Haefele, Alexander; Kmpfer, Niklaus

367

Vapor Pressure Measurement for 4He Films Adsorbed on 2D Mesoporous Hectorite  

NASA Astrophysics Data System (ADS)

The vapor-pressure measurement for adsorbed films is equivalent to the measurement of the chemical potential. By the measurement of 4He films adsorbed on two-dimensional (2D) mesoporous Hectorite, we obtained the 2D isothermal compressibility, the isosteric heat, and the effective thickness deduced from the FHH model, mainly above a coverage of 15 ?mol/m2. The compressibility shows two dips at n1 = 17.5+/-0.5 ?mol/m2 and n2 = 22.7+/-0.5 ?mol/m2 which correspond to the first layer completion and appearance of the quantum-Bose-fluid layer, respectively. For the quantum-Bose-fluid layer, the phonon velocity deduced from the compressibility is on the order of 100 m/s, and it reasonably agrees with that obtained from the 2D phonon heat capacity.

Asano, Ryota; Toda, Ryo; Matsushita, Yuki; Hieda, Mitsunori; Matsushita, Taku; Wada, Nobuo

2006-09-01

368

Vapor Pressure of Three Brominated Flame Retardants Determined via Knudsen Effusion Method  

PubMed Central

Brominated flame retardants (BFRs) have been used in a variety of consumer products in the past four decades. The vapor pressures 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.

Fu, Jinxia; Suuberg, Eric M.

2012-01-01

369

Defect Characterization in Ge/(001)Si Epitaxial Films Grown by Reduced-Pressure Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

We studied the microstructural characteristics and electrical properties of epitaxial Ge films grown on Si(001) substrates by x-ray diffraction, atomic force microscopy, and transmission electron microscopy. The films were grown using a two-step technique by reduced-pressure chemical vapor deposition, where the first step promotes two-dimensional growth at a lower substrate temperature. We observed a decrease in defect density with increasing film thickness. Ge films with thickness of 3.5 ?m exhibited threading dislocation densities of 5 106 cm-2, which yielded devices with dark current density of 5 mA cm-2 (1 V reverse bias). We also noted the presence of stacking faults in the form of lines in the films and establish that this is an important defect for Ge films grown by this deposition technique.

Bharathan, Jayesh; Narayan, Jagdish; Rozgonyi, George; Bulman, Gary E.

2013-10-01

370

High-pressure vapor-liquid equilibrium for R-22 + ethanol and R-22 + ethanol + water  

SciTech Connect

High-pressure vapor-liquid equilibrium (VLE) data for the systems CO{sub 2} + methanol at 313.05 K, CO{sub 2} + ethanol at 323.55, 325.15, and 333.35 K, R-22 (chlorodifluoromethane) + ethanol at 343.25, 361.45, and 382.45 K, and R-22 + ethanol + water at 351.55, 362.65, and 371.85 K are obtained using a circulation-type VLE apparatus. The apparatus is tested with measurements of the CO{sub 2} + methanol and CO{sub 2} + ethanol systems. The experimental data are correlated using the Peng-Robinson and Elliott-Suresh-Donohue equations of state.

Elbaccouch, M.M.; Raymond, M.B.; Elliott, J.R.

2000-04-01

371

High-pressure vapor-liquid equilibria for mixtures containing a supercritical fluid  

SciTech Connect

Supercritical fluid extraction has been proven as an efficient separation method for some specific industrial applications. The knowledge of the phase behavior of supercritical systems plays an important role in the process design. High pressure vapor-liquid phase equilibrium compositions were measured for the binary systems of carbon dioxide + 2-methyl-1-pentanol, carbon dioxide + 1-octanol, and carbon dioxide + 1-decanol over a temperature range between 348.15 and 453.15 K. In addition to the new data, a variety of supercritical fluid systems was used to test the validity of the Peng-Robinson and Patel-Teja equations of state accompanied by several types of mixing rules. In general, the Peng-Robinson equation incorporated with the cubic mixing rule yielded the best representation.

Weng, W.L. (Ming-Hsin Engineering College, Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering); Chen, J.T.; Lee, M.J. (National Taiwan Inst. of Technology, Taipei (Taiwan, Province of China). Dept. of Chemical Engineering)

1994-08-01

372

Generalization of vapor pressure lowering effects in an existing geothermal simulator  

SciTech Connect

Thermodynamic properties of pore water are shown to be different from those of bulk water because of interfacial forces between the aqueous and solid phases. This {open_quotes}vapor-pressure lowering{close_quotes} (VPL) effect is described through Kelvin`s equation, which relates VPL to properties of the liquid phase. An algorithm that accounts for VPL had previously been implented in the geothermal simulator TETRAD. This algorithm applies to a narrow range of reservoir properties, and in some cases leads in inconsistencies. This report presents a generalization of the VPL algorithm which removes many of its limitations. The governing equations for the generalization are presented, assumptions and limitations of the method are discussed, and the modifications are validated.

Shook, G.M.

1993-06-01

373

Relationship between Saturation Exposure Pressure and Subsequent Decompression Sickness in Mice.  

National Technical Information Service (NTIS)

While pressure reduction is acknowledged to be the single most cogent factor in producing decompression sickness, little has been done to define accurately the allowable limits beyond 2 ATA. This study provides some theoretical guidelines for future manne...

T. E. Berghage F. W. Armstrong K. J. Conda

1975-01-01

374

Growth and characterization of indium nitride layers grown by high-pressure chemical vapor deposition  

NASA Astrophysics Data System (ADS)

In this research the growth of InN epilayers by high-pressure chemical vapor deposition (HPCVD) and structural, optical properties of HPCVD grown InN layers has been studied. We demonstrated that the HPCVD approach suppresses the thermal decomposition of InN, and therefore extends the processing parameters towards the higher growth temperatures (up to 1100K for reactor pressures of 15 bar, molar ammonia and TMI ratios around 800, and a carrier gas flow of 12 slm). Structural and surface morphology studies of InN thin layers have been performed by X-ray diffraction, low energy electron diffraction (LEED), auger electron spectroscopy (AES), high-resolution electron energy loss spectroscopy (HREELS) and atomic force microscopy (AFM). Raman spectroscopy, infrared reflection, transmission, photoluminescence spectroscopy studies have been carried out to investigate the structural and optical properties of InN films grown on sapphire and GaN/sapphire templates. InN layers grown on a GaN (0002) epilayer exhibit single-phase InN (0002) X-ray diffraction peaks with a full width at half maximum (FWHM) around 200 arcsec. Auger electron spectroscopy confirmed the cleanliness of the surface, and low energy electron diffraction yielded a 1x1 hexagonal pattern indicating a well-ordered surface. The plasmon excitations are shifted to lower energies in HREEL spectra due to the higher carrier concentration at the surface than in the bulk, suggesting a surface electron accumulation. The surface roughness of samples grown on GaN templates is found to be smoother (roughness of 9 nm) compared to the samples grown on sapphire. We found that the deposition sometimes led to the growth of 3 dimensional hexagonal InN pyramids. Results obtained from Raman and IR reflectance measurements are used to estimate the free carrier concentrations, which were found in the range from mid 1018 cm-3 to low 10 20 cm-3. The optical absorption edge energy calculated from the transmission spectra is 1.2 eV for samples of lower electron concentration. The Raman analysis revealed a high-quality crystalline layer with a FWHM for the E2(high) peak around 6.9 cm-1. The results presented in our study suggest that the optimum molar ratio might be below 800, which is due to the efficient cracking of the ammonia precursor at the high reactor pressure and high growth temperature. Index words. Indium Nitride, In-rich group III Nitrides, III-V semiconductors, High-Pressure, Chemical Vapor Deposition, V/III molar ratio.

Alevli, Mustafa

375

White Light Mie Resonance Spectroscopy Used to Measure Very low Vapor Pressures of Substances in Aqueous Solution Aerosol particles  

NASA Astrophysics Data System (ADS)

We report a novel and fairly simple optical technique for sizing and measuring the evaporation rates of aqueous solution aerosol particles. A ball-lens LED with high degree of spatial coherence is used as a white light source to excite the Morphology Dependent Resonance (MDR) spectra of a microdroplet levitated in an electrodynamic balance (EDB). The spectra are recorded by an Optical Multichannel Analyzer. We show that very low vapor pressures of substances in aqueous solution particles can be measured for different temperatures and relative humidities (hence for different concentrations). As an application we measured the vapor pressure and the enthalpy of vaporization of aqueous malonic acid, a substance of interest for atmospheric science.

Zardini, A. A.; Krieger, U. K.; Marcolli, C.

2006-12-01

376

White light Mie resonance spectroscopy used to measure very low vapor pressures of substances in aqueous solution aerosol particles  

NASA Astrophysics Data System (ADS)

We report a novel and fairly simple optical technique for sizing and measuring the evaporation rates of aqueous solution aerosol particles. A ball-lens LED with high degree of spatial coherence is used as a white light source to excite the Morphology Dependent Resonance (MDR) spectra of a microdroplet levitated in an electrodynamic balance (EDB). The spectra are recorded by an Optical Multichannel Analyzer. We show that very low vapor pressures of substances in aqueous solution particles can be measured for different temperatures and relative humidities (hence for different concentrations). As an application we measured the vapor pressure and the enthalpy of vaporization of aqueous malonic acid, a substance of interest for atmospheric science.

Zardini, Alessandro A.; Krieger, Ulrich K.; Marcolli, Claudia

2006-07-01

377

Comparison of Deposition Characteristics between Triethyl and Trimethyl Borates in an Atmospheric Pressure Chemical Vapor Deposition Equipment with Tetraethyl Orthosilicate and O3  

NASA Astrophysics Data System (ADS)

The deposition characteristics of triethyl borate (TEB) and trimethyl borate (TMB) vapors are compared to investigate of boron concentration uniformity and profiles in borophosphosilicate glass (BPSG) films. Film deposition is carried out in an atmospheric pressure equipment with tetraethyl orthosilicate (TEOS) and ozone (O3) under at standard condition and four process parameters are varied around the standard condition. Uniformity values obtained with the TMB vapor at a bubbling temperature of 10C are one-third that with the TEB vapor at the same bubbling temperature, and uniformity changes due to process parameter variations from the standard condition with the TMB vapor are also smaller since the TEB vapor is cleaved by O3 at lower temperature. These results indicate that the deposition characteristics for uniformity using TMB vapor are much better. However, a decrease in the boron concentration profile in films with the TMB vapor is observed between a silicon and silicon-dioxide interface. This decrease is estimated to be due to the fact that TMB bubbling N2 flow rate to suppress the vaporization rate with TMB's higher vapor pressure is one order of magnitude lower than TEB bubbling N2 flow rate. Suppression of TMB vapor to a desired vapor pressure was achieved by cooling the TMB bubbler at -25C. Then, a uniform profile of the TMB vapor was obtained, which was equivalent to the results at 10C.

Yamamoto, Yoshito; Ikakura, Hiroshi; Ohgawara, Shoji; Furukawa, Masakazu

1999-09-01

378

Ideal-gas and saturation properties of methanol  

SciTech Connect

Properties of the ideal gas have been considered in detail and new equations for the ideal-gas heat capacity enthalpy, and entropy are given which are valid from 100 to 1000 K. Saturation-curve data have been reviewed and an equation for the vapor pressure is given which covers the whole range from the triple point to the critical point. A tentative equation for the saturated liquid density is also given. The necessity for new experimental measurements is discussed.

Craven, R.J.B.; de Reuck, K.M.; Hauley, H.J.M; Cezairliyan, A.

1986-05-01

379

Vapor pressure and gas phase PVT data and correlation for 1,1,1-trifluoroethane (R143a)  

Microsoft Academic Search

A constant volume apparatus has been used to measure the vapor pressure and single phase densities (PVT) for 1,1,1-trifluoroethane (R143a), an ozone friendly refrigerant. The sample has a purity greater than 99.91% by mass. The measurements were done from 244 to 365 K at pressures up to 4.4 MPa and at densities ranging from 5% to 99% of the critical

G. Giuliani; F. Polonara; S. Kumar; P. Zazzini

1995-01-01

380

Oxidizer partial pressure window for YBa2Cu3O(7-x) thin film formation by metalorganic chemical vapor deposition  

Microsoft Academic Search

We conducted a systematic study of oxidizer partial pressure effects on both the superconducting transport properties and structural properties of YBa2Cu3O(7-x) (YBCO) films grown by conventional metalorganic chemical vapor deposition (MOCVD). Superconducting YBCO thin films were grown in partial N2O pressures ranging from 0.4 to 45 Torr and at substrate temperatures of 500 and 700 C. We observed a window

C. S. Chern; J. Zhao; P. E. Norris; S. M. Garrison; K. Yau; Y. Q. Li; B. M. Gallois; B. H. Kear

1992-01-01

381

Oxidizer partial pressure window for YBa2Cu3O7?x thin film formation by metalorganic chemical vapor deposition  

Microsoft Academic Search

We have conducted a systematic study of oxidizer partial pressure effects on both the superconducting transport properties and structural properties of YBa2Cu3O7?x (YBCO) films grown by conventional metalorganic chemical vapor deposition (MOCVD). Superconducting YBCO thin films were grown in partial N2O pressures ranging from 0.4 to 45 Torr and at substrate temperatures of 500 and 700 C. We have observed

C. S. Chern; J. Zhao; P. E. Norris; S. M. Garrison; K. Yau; Y. Q. Li; B. M. Gallois; B. H. Kear

1992-01-01

382

High-pressure vapor-liquid equilibria involving mixtures of nitrogen, carbon dioxide, and eta-butane  

Microsoft Academic Search

A new high-pressure vapor-liquid equilibrium apparatus has been constructed with the capability of measuring the compositions and densities of the coexisting equilibrium phases at constant temperature and\\/or pressure. This apparatus was tested with the carbon dioxide + n-butane system with excellent agreement observed between our results and previously published data. Data are also reported for the nitrogen + n-butane system

Steven K. Shibata; Stanley I. Sandler

1989-01-01

383

Tropospheric water vapor profiles retrieved from pressure broadened emission spectra at 22 GHz under clear sky conditions  

Microsoft Academic Search

We present a characterization and first results of the optimal estimation retrieval of water vapor profiles from the surface up to 10 km from pressure broadened emission spectra. The spectra have a bandwidth of 1 GHz and are centered around 22.235 GHz. The measurements are made by a ground based heterodyne receiver equipped with a digital FFT spectrometer and calibrated

A. Haefele; N. Kmpfer

2009-01-01

384

Review of methods and measurements of selected hydrophobic organic contaminant aqueous solubilities, vapor pressures, and air-water partition coefficients  

Microsoft Academic Search

Aqueous solubilities, vapor pressures, and Henry`s law constants for a wide range of organic contaminants of environmental interest are presented. Specifically, a discussion of methods used to measure these physical constants and resulting measurements are provided in an effort to examine the scope of physical constants reported in the scientific literature. Physical constants reviewed include those for 40 PAHs, 14

H. A. Bamford; J. E. Baker; D. L. Poster

1998-01-01

385

COMPUTATIONAL CHEMISTRY METHOD FOR PREDICTING VAPOR PRESSURES AND ACTIVITY COEFFICIENTS OF POLAR ORGANIC OXYGENATES IN PM2.5  

EPA Science Inventory

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. Vapor pressures and activity coefficients of these compo...

386

An Integrated Approach to Introducing Biofuels, Flash Point, and Vapor Pressure Concepts into an Introductory College Chemistry Lab  

ERIC Educational Resources Information Center

|Students explore the fundamental chemical concepts of vapor pressure 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

Hoffman, Adam R.; Britton, Stephanie L.; Cadwell, Katie D.; Walz, Kenneth A.

2011-01-01

387

VAPOR PRESSURE OF ALKALI METALS. RUBIDIUM, CESIUM, AND SODIUM-POTASSIUM ALLOY (NaK) UP TO 100 PSI  

Microsoft Academic Search

The vapor pressures of high-purity cesium, rubidium, and NaK (sodium--; potassium alloy) of 30.6 wt % sodium were measured from roughly 1 to 100 lb psi ; abs. The method employed boiling under argon, in a small capsule to ensure ; temperature uniformity. Recent independert results by others on sodium, in close ; agreement with earlier sodium data obtained with

C. F. Bonilla; D. L. Sawhney; M. M. Makansi

1962-01-01

388

DETERMINATION OF THE VAPOR PRESSURES OF SELECT POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS AT 75275C  

EPA Science Inventory

Vapor pressures were determined for several polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at 75275C, extending the available literature data to more relevant temperature regions and providing the first experimental data for 2,3,7...

389

Vapor Pressure and Thermodynamics of Selenium Dioxide. The Enthalpy of Atomization of SeO2(g).  

National Technical Information Service (NTIS)

The equilibrium vapor pressures and thermochemical properties of selenium dioxide are of practical importance to the non-ferrous metals industry since a major portion of the world's supply of metallic selenium is obtained as SeO2 in the oxidative roasting...

R. G. Behrens R. S. Lemons G. M. Rosenblatt

1973-01-01

390

The influence of water vapor content on electrical and spectral properties of an atmospheric pressure plasma jet  

Microsoft Academic Search

An atmospheric pressure plasma jet generated in Ar with water vapor is investigated. It is shown that an increase in the water content results in a decrease in the input power and asymmetry of the current waveform on positive and negative half-periods of the applied voltage. Space-resolved spectroscopy with a resolution of 1 mm and an imaging technique are applied

A. Yu Nikiforov; A. Sarani; Ch Leys

2011-01-01

391

Vapor pressures of pure compounds using the PengRobinson equation of state with three different attractive terms  

Microsoft Academic Search

Accurate representation of pure compounds vapor pressures is required to increase the robustness of equations of state when predicting phase equilibria for mixtures. Using cubic equations of state, this representation largely depends on improving the temperature-dependent attractive term of the equation of state (EOS) to cover data from the triple to critical points. With this purpose, the PengRobinson equation of

Otilio Hernndez-Garduza; Fernando Garc??a-Snchez; David pam-Mart??nez; Richart Vzquez-Romn

2002-01-01

392

Growth analysis of novel ZnO nanotetrapods with tubular legs from aspect of reagent's vapor pressure and growth temperature  

NASA Astrophysics Data System (ADS)

In this article, novel ZnO nanotetrapods with tubular legs was successfully synthesized using mixed powder of Zn, ZnO, and carbon as source. The growth process was analyzed at large, and a two-step growth model, viz. initial deficient-oxidation and latter second-volatilization, was proposed to explain the formation of tubular leg of ZnO nanotetrapod. In the growth model, the high Zn vapor pressure and high growth temperature were considered as two crucial factors determining the growth behavior. Zn-rich ZnO nanotetrapod formed under high Zn vapor pressure at the initial stage. These redundant Zn clusters coexisted in ZnO lattice as interstitial Zn. The following second-volatilization of interstitial Zn under high growth temperature led to formation of tubular leg. Four other experiments were designed to analyze the growth behavior under high and low Zn vapor pressure and growth temperature, respectively, and these experimental results further confirmed the validity of our growth model. Our experiment proposed a feasible synthesis route to prepare hollow nanostructures controlled by the vapor pressure and growth temperature. Furthermore, these novel ZnO nanotetrapods might have potential application as building blocks for functional nanodevices.

Yan, Youguo; Zhou, Lixia; Zhang, Jun; Hu, Songqing; Sun, Shuangqing; Zhen, Yuhua

2012-11-01

393

Numerical Simulations of Films Formed by Cluster/Particle Co-Deposition in Atmospheric-Pressure Chemical Vapor Deposition Process Using Organic Silicon Vapors and Ozone Gas  

NASA Astrophysics Data System (ADS)

In order to confirm the previously developed numerical simulation for film formation by cluster/particle co-deposition in the atmospheric-pressure chemical vapor deposition [Fujimoto ?l.: J. Appl. Phys. 85 (1999) 4196], simulation results were compared with experimentally obtained growth rates and surface morphologies of films prepared from four organic silicon vapors [tetraethylorthosilicate (TEOS), triethoxysilane (TRIES), tetramethylorthosilicate (TMOS), and octamethylcyclotetrasiloxane (OMCTS)] and ozone gas using a flow-type vertical tube reactor. For TEOS, TRIES and TMOS, the simulation results could explain reasonably experimentally determined film growth rate, particle deposition rate and surface morphology of film when natural convection did not occur in the reactor. However, the numerical simulation could not estimate film formation from OMCTS.

Adachi, Motoaki; Fujimoto, Toshiyuki; Itoh, Yoshifumi; Okuyama, Kikuo

2000-06-01

394

Microstructures of graphite spherulites grown in carbon-saturated liquid nickel matrix under high pressure  

SciTech Connect

In steel processing, the nodular or ductile cast irons containing spherical particles of carbon have been studied extensively. The spherical particles are known as graphite spherulites (GS). The GSs are obtained by direct solidification of the melt of a ductile cast iron with addition of an inoculant. Besides the GSs in the nodular cast irons, GSs were formed in a liquid Ni-C alloy at atmospheric pressure by adding lanthanum or simply by rapid cooling from a liquid state. Impurities have been assumed to play an important role on the morphological changes of graphite from flakes to spherulites. Interestingly, the GSs were also formed in a liquid nickel at high pressures and temperatures. The formation of GSs was ascribed to an abrupt dissociation of nickel carbide (Ni{sub x}C) during cooling since the Ni{sub x}C could exist only at high pressures and became unstable at atmospheric pressure above 900 C. The formation and growth mechanisms of GSs in the Ni-C alloy have not yet been studied. The objective of the present study is to determine the internal microstructure of GSs formed in a liquid nickel in contact with graphite at diamond-stable conditions and to propose a growth mechanism of GSs.

Park, J.K.; Kim, S.C. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of)

1997-06-15

395

Atmospheric-Pressure Chemical Vapor Deposition of Iron Pyrite Thin Films  

SciTech Connect

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-pressure chemical vapor 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 pressure during annealing. Phase and elemental composition of the films are characterized by 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.

Berry, Nicholas; Cheng, Ming; Perkins, Craig L.; Limpinsel, Moritz; Hemminger, John C.; Law, Matt (NREL); (UCI)

2012-10-23

396

Fabrication of Whitely Luminescent Silicon-Rich Nitride Films by Atmospheric Pressure Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

Silicon-rich nitride (SRN) films that can exhibit an intense white-light emission were fabricated by atmospheric pressure chemical vapor deposition. SRN films were deposited on Si substrates using gaseous SiH2Cl2 (DCS) and NH3 as the source materials for Si and N, respectively. The deposition temperature was kept at 850 C, and H2 was used as the carrier gas with its flow rate modulated to maintain chamber pressure at 1 atm during the deposition. The optical properties of films obtained at various deposition times from 15 to 60 min were examined by photoluminescence (PL) measurement. An intense luminescence band (1.5-3.5 eV) was observed by the naked eye for all as-deposited samples. Besides, time-resolved PL exhibited a short radiative lifetime of about 1 ns for SRN films. Moreover, high resolution plan-view transmission electron microscopy demonstrated the existence of Si dots in SRN films with the dot sizes ranging from 2 to 6 nm and a dot density of about 4 1012/cm2. On the basis of the results obtained, we considered that the related luminescence mechanism for SRN films is connected to crystalline Si dots produced therein.

Lin, Chia-Hung; Uen, Wu-Yih; Huang, Yen-Chin; Li, Zhen-Yu; Liao, Sen-Mao; Yang, Tsun-Neng; Lan, Shan-Ming; Huang, Yu-Hsiang

2008-06-01

397

Modeling Conditional Stability of Gravity-Driven Unsaturated Infiltrating Flows Using a Non-equilibrium Capillary Pressure-Saturation Relation  

NASA Astrophysics Data System (ADS)

Gravity-driven unstable flow during infiltration in unsaturated porous media is considered to be an important preferential flow process. The conventional equation for modeling unsaturated flows is the Richards equation, but this equation cannot be used to model unstable flows as it has been shown (A.G. Egorov, R.Z. Dautov, J.L. Nieber, and A.Y. Sheshukov, 2003. Stability analysis of gravity-assisted infiltrating flow, Water Resour. Res., 39:,1266, doi:10.1029/2002WR001886) that solutions to the Richards equations are unconditionally stable. Therefore, modeling these unstable flows requires the use of new forms of the mass balance equation which contain features that might account for the cause of instabilities. One postulated cause for instabilities is the existence of non-equilibrium in the capillary pressure-saturation relation. In this presentation we will examine the conditional stability that results from the use of a non-equilibrium relation of the form ? (S,p){? S}/{? t}=p-P(S), where ? is the relaxation coefficient, S is the saturation, p is the dynamic pressure, and P(S) is the equilibrium pressure. The stability analysis is based on the perturbation of the traveling wave form of the governing mass balance equation and the associated relaxation equation. The numerical determination of the eigenvalues of the resulting perturbation equations yields the critical growth factor as related to perturbation frequency. The derived critical growth factor is used in evaluating the conditional stability as to its sensitivity to the flux and magnitude of the relaxation coefficient. It is interesting to see that as ? (S,p)-> 0 the flow becomes unconditionally stable, the result being that found for the Richards equation. The perturbation frequency associated with the critical growth factor is related to finger width and this is confirmed with simulations in the two-dimensional vertical plane.

Dautov, R. Z.; Egorov, A. G.; Nieber, J. L.; Sheshukov, A. Y.

2004-12-01

398

Correlation and prediction of physical properties of hydrocarbons with the modified Peng-Robinson equation of state 1. Low and medium vapor pressures  

Microsoft Academic Search

A modified version of the Peng-Robinson equation of state is proposed for representing vapor pressure data on compounds currently encountered in petroleum fractions. The proposed equation is valid from the triple point up to 2-3 bar. When one parameter is adjusted using experimental data, a very accurate representation of vapor pressures is obtained, with an overall average absolute deviation of

B. Carrier; M. Rogalski; A. Peneloux

1988-01-01

399

Development and application of very high temperature mass spectrometry. Vapor pressure determinations over liquid refractories  

Microsoft Academic Search

Existing thermodynamic and vaporization data for liquid refractories are based either on estimates or on data extrapolated from studies on the solids obtained at much lower temperatures. Previously, we have shown that pulsed laser heating, coupled with time- dependent mass spectrometry of the free-expansion vapor plume, can be used for semi-quan- titative measurements of vaporization thermochemistry. The present work extends

J. W. Hastie; D. W. Bonnell; P. K. Schenck

2000-01-01

400

First experimental determination of the absolute gas-phase rate coefficient for the reaction of OH with 4-hydroxy-2-butanone (4H2B) at 294 K by vapor pressure measurements of 4H2B.  

PubMed

The reaction of the OH radicals with 4-hydroxy-2-butanone was investigated in the gas phase using an absolute rate method at room temperature and over the pressure range 10-330 Torr in He and air as diluent gases. The rate coefficients were measured using pulsed laser photolysis (PLP) of H(2)O(2) to produce OH and laser induced fluorescence (LIF) to measure the OH temporal profile. An average value of (4.8 1.2) 10(-12) cm(3) molecule(-1) s(-1) was obtained. The OH quantum yield following the 266 nm pulsed laser photolysis of 4-hydroxy-2-butanone was measured for the first time and found to be about 0.3%. The investigated kinetic study required accurate measurements of the vapor pressure of 4-hydroxy-2-butanone, which was measured using a static apparatus. The vapor pressure was found to range from 0.056 to 7.11 Torr between 254 and 323 K. This work provides the first absolute rate coefficients for the reaction of 4-hydroxy-2-butanone with OH and the first experimental saturated vapor pressures of the studied compound below 311 K. The obtained results are compared to those of the literature and the effects of the experimental conditions on the reactivity are examined. The calculated tropospheric lifetime obtained in this work suggests that once emitted into the atmosphere, 4H2B may contribute to the photochemical pollution in a local or regional scale. PMID:23210721

El Dib, Gisle; Sleiman, Chantal; Canosa, Andr; Travers, Daniel; Courbe, Jonathan; Sawaya, Terufat; Mokbel, Ilham; Chakir, Abdelkhaleq

2012-12-24

401

Transport of Carbon Tetrachloride in a Fractured Vadose Zone due to Atmospheric Pressure Fluctuations, Diffusion, and Vapor Density  

NASA Astrophysics Data System (ADS)

DNAPL sources of carbon tetrachloride (CT) vapors 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 pressure fluctuations serve as driving forces for CT vapor transport in the subsurface. Other important transport processes for vapor 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 pressure and vapor concentration measurements were conducted at various depths in two wells. A numerical multiphase flow model (TOUGH2), calibrated to field pressure 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 pressure 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 pressure 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 vapor 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.

McCray, J. E.; Downs, W.; Falta, R. W.; Housley, T.

2005-12-01

402

The Effect of Films on the Capillary Pressure - Saturation Hysteresis in a Smooth-walled Wedge Channel  

NASA Astrophysics Data System (ADS)


Thin fluid films are central to many multiphase flow applications; however, experimental investigation of films requires direct detection and measurement of films. Water film thicknesses can range from a few nanometers to several micrometers and may vary depending on local pore structures and material properties. In this study, laser confocal microscopy was employed to image volumetric fluid distribution and 3D interfaces during drainage and imbibition processes in a smooth-walled channel. Confocal microscopy provides an effective method to image directly 3D thin films and to measure film thickness, volume, and other parameters. The detection resolution is 1.19 ?m/pixel through a 10x objective lens and is 0.72 ?m/pixel through a 20x lens. A smooth-walled wedge channel was fabricated to study the generation and relaxation of water films in the non-wetting phase of air. The effect of films on contact angle, interfacial area per volume (IAV), and capillary pressure - saturation (Pc - Sw) hysteresis were also investigated.
Micromodels were fabricated using a negative photoresist (SU-8) sandwiched between two cover glasses. An all-SU-8 smooth-walled wedge channel was fabricated by laser direct-writing two-photon polymerization, 100 ?m wide at the outlet and 20 ?m at the inlet with a constant aperture of 40 ?m. A laser scanning confocal microscope was used to image the wetting (water) and non-wetting (air) phase distributions by labeling the wetting phase with a fluorophore, Alex Fluor-488, 1.0% by wieght. The 3D air-water interfaces were imaged and then reconstructed using a stack of confocal images. The samples were initially saturated with water, the wetting phase. A series of drainage and imbibition cycles were performed by incrementing or decrementing the air pressure. At each pressure, the system was allowed to equilibrate and then a stack of scans in depth was collected to acquire the 3D fluid distribution for the given pressure. The confocal images were analyzed to extract the volume saturation of water, IAV, and contact angle.
Thin films of water between the air and the solid phase (SU-8 channel) were observed in the wedge micro-channel. The presence of films were found to increase the capillary pressure relative to the condition with no films by 0 ~ 1300 Pa as a function of wetting phase saturation. Force balance analysis was performed based on the contact angle at the common line, which shows an additional surface tension from the film that is approximately 1/10 that of the water surface tension. The same energy expended for the hysteresis loops was found between with and without film. In addition, only partial film relaxation is observed when a hysteresis scan is paused.
Acknowledgments: This research is supported by the National Science Foundation (0911284-EAR).

Liu, Y.; Nolte, D.; Pyrak-Nolte, L. J.

2010-12-01

403

Atmospheric loss and supply by an impact-induced vapor cloud: Its dependence on atmospheric pressure on a planet  

NASA Astrophysics Data System (ADS)

Hypervelocity impact would vaporize the impactor and part of planetary surface and create a rock vapor cloud. Results from previous studies suggest that the energetic impact would have a role to blow off and cause a large-scale loss of the planetary atmosphere through expansion of the vapor cloud. Impact also has been considered as a material source. Numerous, repeated impact events during the heavy bombardment period could greatly affect the amount of volatiles and the atmospheric pressure on the planetary surface in either way. To discuss the evolution of the atmospheric pressure by impacts, we carried out hydro-calculations with a two-dimensional hydrodynamic code and investigated the dependence of the loss and supply of the atmosphere on the atmospheric pressure. We integrated both effects by impacts over impactor size distribution and assessed the evolution of the atmospheric pressure on early Mars. Using this approach, we found that the numerous impacts likely increase the atmosphere monotonically or control the atmospheric pressure to some value, rather than causing the monotonic decrease as the previous study suggested.

Hamano, K.; Abe, Y.

2010-07-01

404

Prediction of vapor-liquid equilibria at high pressures using activity coefficient parameters obtained from low-pressure data: A comparison of two equation of state mixing rules  

SciTech Connect

Two recent equation of state mixing rules, one by Dahl and Michelsen (MHV2) and another by Wong and Sandler (W-S), are claimed to be useful for making vapor-liquid equilibrium predictions for nonideal mixtures at high temperatures and pressures using data obtained at low pressures. Here the authors compare the performance of these two mixing rules in predicting the high-pressure phase behavior of nine binary systems using published activity coefficient parameters. They also compare the predictions for two ternary systems using mixing rule parameters obtained from low-pressure binary mixture data. They find that both mixing rules can be used to make reasonable high-pressure vapor-liquid equilibrium predictions from low-pressure data. However, the errors in the predicted pressure with the W-S mixing rule when used with either the Peng-Robinson or Soave-Redlich-Kwong equation of state are, on the average, about half or less those obtained when using the MHV2 mixing rule. Also, the predictions of the MHV2 mixing rule deteriorate significantly as the temperature and pressure range increase, which is not the case with the W-S mixing rule.

Huang, Hai; Sandler, S.I. (Univ. of Delaware, Newark (United States). Dept. of Chemical Engineering)

1993-07-01

405

Vaporization of sediments with a pulsed transverse excitation at atmospheric pressure (TEA) CO/sub 2/ laser system  

SciTech Connect

A transverse excitation at atmospheric pressure (TEA) pulsed CO/sub 2/ laser equipped with an adjunct called a Lasertrace has been used to generate vapor and/or particulates from sediment samples. The material thus obtained can be transferred to analytical systems for analysis making possible the analysis of solids by techniques previously suitable only for liquids or gases. Approximately one milligram of vapor and/or particulates was obtained in a short period of time by this method, suitable for transport to other systems.

Smyrl, N.R.; King, H.G. Jr.

1981-12-31

406

Osmotic virial coefficients of hydroxyethyl starch from aqueous hydroxyethyl starch-sodium chloride vapor pressure osmometry.  

PubMed

Hydroxyethyl starch (HES) is an important industrial additive in the paper, textile, food, and cosmetic industries and has been shown to be an effective cryoprotectant for red blood cells; however, little is known about its thermodynamic solution properties. In many applications, in particular those in biology, HES is used in an aqueous solution with sodium chloride (NaCl). The osmotic virial solution thermodynamics approach accurately captures the dependence of osmolality on molality for many types of solutes in aqueous systems, including electrolytes, sugars, alcohols, proteins, and starches. Elliott et al. proposed mixing rules for the osmotic virial equation to be used for osmolality of multisolute aqueous solutions [Elliott, J. A. W.; et al. J. Phys. Chem. B 2007, 111, 1775-1785] and recently applied this approach to the fitting of one set of aqueous HES-NaCl solution data reported by Jochem and Krber [Cryobiology 1987, 24, 513-536], indicating that the HES osmotic virial coefficients are dependent on HES-to-NaCl mass ratios. The current study reports new aqueous HES-NaCl vapor pressure osmometry data which are analyzed using the osmotic virial equation. HES modifications were measured after dialysis (membrane cut off: 10?000 g/mol) and freeze-drying using vapor pressure osmometry at different mass ratios of HES to NaCl for HES up to 50% and NaCl up to 25% with three different HES modifications (weight average molecular weights [g/mol]/degree of substitution: 40?000/0.5; 200?000/0.5; 450?000/0.7). Equations were then fit to the data to provide a model for HES osmotic virial coefficient dependence on mass ratio of HES to NaCl. The osmolality data of the three HES modifications were accurately described over a broad range of HES-to-NaCl mass ratios using only four parameters, illustrating the power of the osmotic virial approach in analyzing complex data sets. As expected, the second osmotic virial coefficients increase with molecular weight of the HES and increase with HES-to-NaCl mass ratio. PMID:23862979

Cheng, Jingjiang; Gier, Martin; Ross-Rodriguez, Lisa U; Prasad, Vinay; Elliott, Janet A W; Sputtek, Andreas

2013-08-26

407

Reversibility of Water Vapor Sorption by Cottage Cheese Whey Solids  

Microsoft Academic Search

Desorption isotherms for water vapor from cottage cheese whey so,lids vary with the way water is first sorbed by the whey solids. When water is sorbed progressively in small increments be- tween zero pressure and saturation pres- sure, the powder becomes 'more porous during lactose crystallization. Subsequent desorption data follow a sigmoid pattern as a function of relative pressure. More

B. A. Anderson

1975-01-01

408

Laser-Saturated Fluorescence Measurements of Nitric Oxide in Laminar, Flat, C2H6\\/O2\\/N2 Flames at Atmospheric Pressure  

Microsoft Academic Search

We have performed both laser-saturated fluorescence (LSF) and linear laser-induced fluorescence (LIF) measurements of NO in lean and rich atmospheric-pressure C2H6\\/O2\\/N2 flames. Unlike previous LSF measurements of OH, NH, and CH, the LSF measurements of NO require a broadband detection scheme, and thus we include a comprehensive theory for broadband LSF. Saturation of NO is found to be easily attainable

JOHN R. REISEL; CAMPBELL D. CARTER; NORMAND M. LAURENDEAU; MICHAEL C. DRAKE

1993-01-01

409

Exchange of Na+ and K+ between water vapor and feldspar phases at high temperature and low vapor pressure  

USGS Publications Warehouse

In order to determine whether gas (steam) containing a small amount of dissolved alkali chloride is effective in promoting base exchange of Na+ and K+ among alkali feldspars and coexisting brine or brine plus solid salt, experiments were carried out at 400-700??C and steam densities ranging down to less than 0.05. For bulk compositions rich in potassium, the low pressure results are close to previous high-pressure results in composition of the fluid and coexisting solid phase. However, when the bulk composition is more sodic, alkali feldspars are relatively richer in potassium at low pressure than at high pressure. This behaviour corresponds to enrichment of potassium in the gas phase relative to coexisting brine and precipitation of solid NaCl when the brine plus gas composition becomes moderately sodic. The gas phase is very effective in promoting base exchange between coexisting alkali feldspars at high temperature and low water pressure. This suggests that those igneous rocks which contain coexisting alkali feldspars out of chemical equilibrium either remained very dry during the high-temperature part of their cooling history or that the pore fluid was a gas containing very little potassium relative to sodium. ?? 1976.

Fournier, R. O.

1976-01-01

410

Solid state phase transition and vapor pressure studies in ammonium nitrate-potassium nitrate binary system  

NASA Astrophysics Data System (ADS)

The solid-state phase transitions in ammonium nitrate (NH4NO 3) and potassium nitrate (KNO3) solid solutions and the equilibrium NH4NO3-KNO3 (AN-KN) phase diagram have been determined. The phase transitions and phase diagram were determined by using the differential scanning calorimetry (DSC) and high temperature X-ray diffractometry. Samples of several different compositions were made for these analyses in a special "Dry Room" with very low humidity. In the X-ray diffraction experiments, the samples were heated on Pt-Rh strip and LaB6 or Si was added for internal calibration. Equilibrium phase diagram was also calculated by using the "FactSage" computer program. A single (AN III) phase region without any phase transitions between 293 to 373 K was observed for compositions between 5 to 25wt% KNO3 in NH4NO3 that is critical for air bag gas generators. The higher temperature KNO3 (KN I) phase has a wide stability range, from 100%KNO3 to 20%KNO3 solution. There is one eutectic, two eutectoids, and two peritectoids in this phase diagram. Two newly discovered solid-state phases were found in the mid-composition range of AN-KN solid solutions. Details of phase equilibria and lattice expansions during heating have been determined. Phase diagram calculations show a reasonable match of the phase boundaries. The total vapor pressures as well as the average molecular weights of pure ammonium nitrate and 16% KNO3 solid solution were measured at various temperatures by the torsion-Knudsen effusion method. The partial pressures of NH4NO3 (PNH4NO 3), NH3 (PNH3), and HNO3 (PHNO 3) have also been determined.

Chien, Wen-Ming

411

Lead, vapor pressure reductions alter domestic refining and gas processing operations  

SciTech Connect

Refiners have altered their operations to accommodate the requirements of the U.S. Environmental Protection Agency's (EPA) lead phasedown rules that went into full effect (maximum 0.1 g/gal) on January 1 of this year. Anticipated new rules governing maximum gasoline vapor pressure will cause further adjustment. Gas processors and gasoline marketers will also be affected. In general, the moves made by refiners to increase octane capability have followed earlier projections. The authors projected that about 250,000 b/d of C/sub 5//C/sub 6/ isomerization would be built - almost 200,000 b/d has already been announced. They estimated that about 500,000 b/d of reforming capacity would be modified or replaced - more than 100,000 b/d of new reformers and almost 200,000 b/d of reformer revamps have already been announced. The use of methyl tertiary butyl ether (MTBE) and alcohol is up dramatically, also as expected. An important new developemnt in octane improvement has been the use of ''high octane'' fluid catalytic cracking (FCC) catalysts. These catalysts have contributed a significant direct octane increase by raising FCC gasoline octane and an indirect effect by increasing FCC olefin production, allowing an increase in the production of high-octane alkylate. Increasing alkylate production in the summer of 1985 dramatically increased refinery isobutane demand.

Smith, L.D.

1986-03-24

412

Solubilities, vapor pressures, densities, and viscosities of the (water + lithium bromide + lithium iodide + lithium chloride) system  

SciTech Connect

Measurements of thermophysical properties of the (water + lithium bromide + lithium iodide + lithium chloride) system (LiBr:LiI:LiCl = 4.5:1:2 by mole ratio) were performed as functions of concentration and temperature. Solubilities were measured by a visual polythermal method at temperatures from (248.59 to 350.46) K. Regression equations were obtained with a least-squares method, and the average absolute deviations of the calculated values from the experimental data were 0.10% (solution temperature < 284.59 K) and 0.12% (temperature {ge} 284.59 K), respectively. The vapor pressures were measured by a boiling point method at lithium salts concentrations from (50.0 to 70.0) mass % and temperatures from (318.36 to 455.75) K. The experimental data were correlated with an Antoine-type equation. The average absolute deviation of the calculated values from the experimental data was 1.83%. Densities and viscosities were measured at concentrations from (50.0 to 64.0) mass % and temperatures from (283.15 to 333.15) K. Regression equations for densities and viscosities were obtained with a least-squares method, and the average absolute deviations of the calculated values from the experimental data were 0.08% and 0.87%, respectively.

Koo, K.K.; Lee, H.R.; Jeong, S. [Sogang Univ., Seoul (Korea, Republic of); Oh, Y.S.; Park, D.R.; Baek, Y.S. [Korea Gas Corp., Ansan (Korea, Republic of). R and D Center

1998-09-01

413

Vapor pressures of water + lithium chloride + ethylene glycol and water + lithium chloride + lithium bromide + ethylene glycol  

SciTech Connect

Aqueous-based working fluids containing several salts or their mixtures concerning primarily lithium bromide have been of much interest for the application to absorption coolers, absorption heat transformers, and absorption heat pumps. The vapor pressures of water + lithium chloride + ethylene glycol and water + lithium chloride + lithium bromide + ethylene glycol (LiCniBr mass ratio 1:1) (H{sub 2}O/C{sub 2}H{sub 6}O{sub 2} mole ratio 10:1) were measured in the temperature ranges from 306.65 to 394.90 K and from 308.10 to 398.20 K and in the absorbent concentration ranges from 11.20 to 45.15 mass % and from 10.01 to 54.17 mass %, respectively. The experimental values were correlated with an Antoine-type equation, and the overall average absolute deviations between the experimental values and the calculated values were found to be 1.65% and 1.03% for the two systems, respectively.

Kim, J.S.; Lee, H. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering; Won, S.H. [Keonyang Univ., Chungnam (Korea, Republic of). Dept. of Mechanical Engineering

1995-03-01

414

As-deposited low-strain LPCVD (Low-Pressure, Chemical-Vapor-Deposition) polysilicon  

NASA Astrophysics Data System (ADS)

As-deposited polysilicon films with very low residual strain (lower than 5 x .00001) are obtained by a low pressure, chemical vapor deposition (LPCVD) process. Straight polysilicon bridges 300 microns long, 1.2 microns thick, and 2 to 20 microns wide, made using this process. No buckling has been observed in any of the nearly one thousand bridges of this type made in two separate process runs. In addition, no problems of sticking between the bridges and the substrate were encountered with these structures. The polysilicon films from which the beams were fabricated were deposited by pyrolyzing silane at 605 C on a phosphosilicate-glass (PSG) layer (8 wt percent P). The PSG layer serves as a sacrificial layer to be subsequently etched away to free the bridge. Our research is aimed at obtaining an understanding of these relationships through consideration of the role of interfacial stresses and the kinetics of initial crystalline nucleation. The technique for producing these low-strain films is significant, however, because no high-temperature annealing steps are required to produce them.

Fan, L. S.; Muller, R. S.

1988-08-01

415

Prediction of aqueous solubility, vapor pressure and critical micelle concentration for aquatic partitioning of perfluorinated chemicals.  

PubMed

The majority of perfluorinated chemicals (PFCs) are of increasing risk to biota and environment due to their physicochemical stability, wide transport in the environment and difficulty in biodegradation. It is necessary to identify and prioritize these harmful PFCs and to characterize their physicochemical properties that govern the solubility, distribution and fate of these chemicals in an aquatic ecosystem. Therefore, available experimental data (10-35 compounds) of three important properties: aqueous solubility (AqS), vapor pressure (VP) and critical micelle concentration (CMC) on per- and polyfluorinated compounds were collected for quantitative structure-property relationship (QSPR) modeling. Simple and robust models based on theoretical molecular descriptors were developed and externally validated for predictivity. Model predictions on selected PFCs were compared with available experimental data and other published in silico predictions. The structural applicability domains (AD) of the models were verified on a bigger data set of 221 compounds. The predicted properties of the chemicals that are within the AD, are reliable, and they help to reduce the wide data gap that exists. Moreover, the predictions of AqS, VP, and CMC of most common PFCs were evaluated to understand the aquatic partitioning and to derive a relation with the available experimental data of bioconcentration factor (BCF). PMID:20958003

Bhhatarai, Barun; Gramatica, Paola

2010-10-19

416

Modeling and Simulation of Arsenic-Doped-Silicon Low-Pressure Chemical Vapor Deposition  

NASA Astrophysics Data System (ADS)

In this paper, we present the modeling and simulation of As-doped-Si low-pressure chemical vapor deposition (LPCVD), in which a Si film growth step using SiH4 and an AsH3 adsorption step are alternately performed (sequential doping is carried out). We focus on the Si film growth in the second step of sequential doping, which involves Si film growth (first step) ? AsH3 adsorption ? Si film growth (second step). The growth thickness and As concentration in the Si film are evaluated with respect to deposition time. As atoms adsorbed on the Si surface after the AsH3 adsorption step are taken up by the Si layer grown in the second step, and some of these atoms precipitate on the Si film surface. The adsorption of SiH4 is suppressed owing to the effect of the As atoms precipitated on the Si film surface, resulting in a decrease in the growth rate of the Si film. On the basis of this finding, we construct a surface reaction model by determining the sticking coefficient of SiH4 from the growth plots in the second step. The Si film growth profiles on submicron holes are analyzed by topography simulation using the surface reaction model, and simulation results are compared with experimentally obtained results.

Kinoshita, Shigeru; Konno, Takuya; Takagi, Shigeyuki; Suzuki, Takashi; Maki, Kunisuke

2007-08-01

417

Characteristics of low vapor pressure oil ignition developed with irradiation of mega hertz level ultrasonic  

Microsoft Academic Search

In liquid fuel vaporizing type combustor for civil use, large amount of the electric power is consumed in pre-heating of fuel vaporizer during a standby period. Reduction of consumed power in pre-heating is regarded as important to develop a performance of the vaporizing type combustor from the viewpoint of energy saving. We proposed the oil combustion system using the MHz-ultrasonic

Takuya Fuse; Yasuki Hirota; Noriyuki Kobayashi; Masanobu Hasatani; Yoshio Tanaka

2004-01-01

418

Control of Photosynthesis and Stomatal Conductance in Ricinus communis L. (Castor Bean) by Leaf to Air Vapor Pressure Deficit.  

PubMed

Castor bean (Ricinus communis L.) has a high photosynthetic capacity under high humidity and a pronounced sensitivity of photosynthesis to high water vapor pressure deficit (VPD). The sensitivity of photosynthesis to varying VPD was analyzed by measuring CO(2) assimilation, stomatal conductance (g(s)), quantum yield of photosystem II (phi(II)), and nonphotochemical quenching of chlorophyll fluorescence (q(N)) under different VPD. Under both medium (1000) and high (1800 micromoles quanta per square meter per second) light intensities, CO(2) assimilation decreased as the VPD between the leaf and the air around the leaf increased. The g(s) initially dropped rapidly with increasing VPD and then showed a slower decrease above a VPD of 10 to 20 millibars. Over a temperature range from 20 to 40 degrees C, CO(2) assimilation and g(s) were inhibited by high VPD (20 millibars). However, the rate of transpiration increased with increasing temperature at either low or high VPD due to an increase in g(s). The relative inhibition of photosynthesis under photorespiring (atmospheric levels of CO(2) and O(2)) versus nonphotorespiring (700 microbars CO(2) and 2% O(2)) conditions was greater under high VPD (30 millibars) than under low VPD (3 millibars). Also, with increasing light intensity the relative inhibition of photosynthesis by O(2) increased under high VPD, but decreased under low VPD. The effect of high VPD on photosynthesis under various conditions could not be totally accounted for by the decrease in the intercellular CO(2) in the leaf (C(i)) where C(i) was estimated from gas exchange measurements. However, estimates of C(i) from measurements of phi(II) and q(N) suggest that the decrease in photosynthesis and increase in photorespiration under high VPD can be totally accounted for by stomatal closure and a decrease in C(i). The results also suggest that nonuniform closure of stomata may occur in well-watered plants under high VPD, causing overestimates in the calculation of C(i) from gas exchange measurements. Under low VPD, 30 degrees C, high light, and saturating CO(2), castor bean (C(3) tropical shrub) has a rate of photosynthesis (61 micromoles CO(2) per square meter per second) that is about 50% higher than that of tobacco (C(3)) or maize (C(4)) under the same conditions. The chlorophyll content, total soluble protein, and ribulose-1,5-bisphosphate carboxylase/oxygenase level on a leaf area basis were much higher in castor bean than in maize or tobacco, which accounts for its high rates of photosynthesis under low VPD. PMID:16669054

Dai, Z; Edwards, G E; Ku, M S

1992-08-01

419

Vapor pressures and evaporation coefficients for melts of ferromagnesian chondrule-like compositions  

NASA Astrophysics Data System (ADS)

To determine evaporation coefficients for the major gaseous species that evaporate from silicate melts, the Hertz-Knudsen equation was used to model the compositions of residues of chondrule analogs produced by evaporation in vacuum by Hashimoto [Hashimoto A. (1983) Evaporation metamorphism in the early solar nebula-evaporation experiments on the melt FeO-MgO-SiO 2-CaO-Al 2O 3 and chemical fractionations of primitive materials. Geochem. J. 17, 111-145] and Wang et al. [Wang J., Davis A. M., Clayton R. N., Mayeda T. K., Hashimoto A. (2001) Chemical and isotopic fractionation during the evaporation of the FeO-MgO-SiO 2-CaO-Al 2O 3-TiO 2 rare earth element melt system. Geochim. Cosmochim. Acta 65, 479-494], in vacuum and in H 2 by Yu et al. [Yu Y., Hewins R. H., Alexander C. M. O'D., Wang J. (2003) Experimental study of evaporation and isotopic mass fractionation of potassium in silicate melts. Geochim. Cosmochim. Acta 67, 773-786], and in H 2 by Cohen et al. [Cohen B. A., Hewins R. H., Alexander C. M. O'D. (2004) The formation of chondrules by open-system melting of nebular condensates. Geochim. Cosmochim. Acta 68, 1661-1675]. Vapor pressures were calculated using the thermodynamic model of Ghiorso and Sack [Ghiorso M. S., Sack R. O. (1995) Chemical mass transfer in magmatic processes IV. A revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid-solid equilibria in magmatic systems at elevated temperatures and pressures. Contrib. Mineral. Petrol. 119, 197-212], except for the late, FeO-free stages of the Wang et al. (2001) and Cohen et al. (2004) experiments, where the CMAS activity model of Berman [Berman R. G. (1983) A thermodynamic model for multicomponent melts, with application to the system CaO-MgO-Al 2O 3-SiO 2. Ph.D. thesis, University of British Columbia] was used. From these vapor pressures, evaporation coefficients ( ?) were obtained that give the best fits to the time variation of the residue compositions. Evaporation coefficients derived for Fe (g), Mg (g), and SiO (g) from the Hashimoto (1983) experiments are similar to those found by Alexander [Alexander C. M. O'D. (2004) Erratum. Meteoritics Planet. Sci. 39, 163] in his EQR treatment of the same data and also adequately describe the FeO-bearing stages of the Wang et al. (2001) experiments. From the Yu et al. (2003) experiments at 1723 K, ?Na = 0.26 0.05, and ?K = 0.13 0.02 in vacuum, and ?Na = 0.042 0.020, and ?K = 0.017 0.002 in 9 10 -5 bar H 2. In the FeO-free stages of the Wang et al. (2001) experiments, ?Mg and ?SiO are significantly different from their respective values in the FeO-bearing portions of the same experiments and from the vacuum values obtained at the same temperature by Richter [Richter F. M., Davis A. M., Ebel D. S., Hashimoto A. (2002) Elemental and isotopic fractionation of Type B calcium-, aluminum-rich inclusions: experiments, theoretical considerations, and constraints on their thermal evolution. Geochim. Cosmochim. Acta 66, 521-540] for CMAS compositions much lower in MgO. When corrected for temperature, the values of ?Mg and ?SiO that best describe the FeO-free stages of the Wang et al. (2001) experiments also adequately describe the FeO-free stage of the Cohen et al. (2004) H 2 experiments, but ?Fe that best describes the FeO-bearing stage of the latter experiment differs significantly from the temperature-corrected value derived from the Hashimoto (1983) vacuum data.

Fedkin, A. V.; Grossman, L.; Ghiorso, M. S.

2006-01-01

420

Computation of partial vapor pressures of aqueous volatile organic compound solutions. Final report, July 1993-December 1995  

SciTech Connect

A program is described for the evaluation of the partial vapor pressures of solution components dependent on the concentration in solution, total pressure, and temperature. The object of the program is to provide reliable values that represent the best estimate based on the large body of experimental data available in the literature. The basis of the estimate is the evaluation of the Wilson coefficients for calculating the activity coefficients of the components using an iterative least squares algorithm to minimize the excess Gibbs free energy of solution. The computational programs are applied to binary aqueous solutions of volatile organic compounds: methanol, ethanol, iso-propanol, acetone, and methyl ethyl ketone. The results are applied to the evaluation of the vapor concentration dependence of the absorbance of selected peaks in the infrared spectrum of the compounds evaluated.

Field, P.E.; Combs, R.J.; Knapp, R.B.

1996-06-01

421

THz laser study of self-pressure and temperature broadening and shifts of water vapor lines for pressures up to 1.4 kPa  

Microsoft Academic Search

The self-broadened linewidths of pure rotational lines of water vapor have been investigated in the temperature range 263340K over a pressure range from 301400Pa using an optically pumped THz photomixer spectrometer having a relative precision of ?10?5cm?1. The lineshapes of several lines between 12 and 52cm?1 were well fit by Lorentzian profiles over the spectral interval spanning 5 FWHM. The

V. B. Podobedov; D. F. Plusquellic; G. T. Fraser

2004-01-01

422

Atmospheric pressure chemical vapor deposition of textured zinc oxide, doped titanium dioxide, and doped zinc oxide thin films  

Microsoft Academic Search

Atmospheric pressure chemical vapor deposition of several thin film materials is described. Textured ZnO films were deposited as a textured antireflection layer on polysilicon solar cells using diethylzinc and water as the precursors. We were able to deposit textured ZnO films of high optical transmittance at a low temperature (250spC) with high growth rates (up to 4000A\\/minute), and good uniformity

Haifan Liang

1998-01-01

423

Vaporliquid equilibrium of carbon dioxide with ethyl caproate, ethyl caprylate and ethyl caprate at elevated pressures  

Microsoft Academic Search

Vaporliquid equilibrium (VLE) data were measured for CO2 with ethyl caproate, ethyl caprylate, and ethyl caprate using a semi-flow type apparatus at 308.2, 318.2 and 328.2 K over the pressure range from 1.6 to 9.2 MPa. In this paper, VLE data are reported. The VLE data were also correlated using the SoaveRedlichKwong and the PengRobinson equations of state with various

Weng-Hong Hwu; Jaw-Shin Cheng; Kong-Wei Cheng; Yan-Ping Chen

2004-01-01

424

Integrated vapor pressure, hygroswelling, and thermo-mechanical stress modeling of QFN package during reflow with interfacial fracture mechanics analysis  

Microsoft Academic Search

In this paper, a comprehensive and integrated package stress model is established for quad flat non-lead package with detailed considerations of effects of moisture diffusion, heat transfer, thermo-mechanical stress, hygro-mechanical stress and vapor pressure induced during reflow. The critical plastic materials, i.e., moldcompound and die attach are characterized for hygroswelling and moisture properties, which are not easily available from material

Tong Yan Tee; Zhaowei Zhong

2004-01-01

425

Study of vapor liquid two-phase frictional pressure drop in a vertical heated spirally internally ribbed tube  

Microsoft Academic Search

Experiments of vapor liquid two-phase frictional pressure drop of upward flow boiling in a smooth tube and in a spirally internally ribbed tube were conducted, respectively. The spirally internally ribbed tube has an outside diameter of 22mm and an inside diameter of 11mm (an equivalent inside diameter of 11.6mm) and the smooth tube has an outside diameter of 19mm and

Lixin Cheng; Tingkuan Chen

2007-01-01

426

Effects of High Water Vapor Pressures on Oxidation of SiC-Based Fiber-Reinforced Composites  

Microsoft Academic Search

The oxidation of SiC-fiber-rei nforced SiC composites at high temperature (1200C) and elevated total water vapor pressures (up to 1.5 atm) was studied. Substantial degradation of SiC composites was observed under these exposure conditions, particularly when BN (used as a fiber coating) was a composite constituent. Besides accelerated SiC recession due to oxidation, the reactions of oxygen and H2O with

K. L. More; P. F. Tortorelli; L. R. Walker

2001-01-01

427

Efficient growth of high-quality graphene films on Cu foils by ambient pressure chemical vapor deposition  

Microsoft Academic Search

We developed an ambient pressure chemical vapor deposition (CVD) for rapid growth of high-quality graphene films on Cu foils. The quality and growth rate of graphene films are dramatically increased with decreasing H2 concentration. Without the presence of H2, continuous graphene films are obtained with a mean sheet resistance of <350 Omega\\/sq and light transmittance of 96.3% at 550 nm.

Libo Gao; Wencai Ren; Jinping Zhao; Lai-Peng Ma; Zongping Chen; Hui-Ming Cheng

2010-01-01

428

Vacuum evaporation of KCl-NaCl salts. Part 1: Thermodynamic modeling of vapor pressures of solid and liquid solutions  

SciTech Connect

In electrorefining to purify plutonium scraps and alloys, typically an equal molar KCl-NaCl mixture is used as the molten electrolyte through which the oxidized Pu ions are transported to the cathode where the pure plutonium is produced and settles by gravity to the bottom of the molten salt. In molten salt extraction, molten KCl-NaCl salt or KCl-NaCl salt containing MgCl{sub 2} is used to extract Am from molten Pu. Over the years the spent salts from these processes have accumulated in substantial quantities throughout various Pu processing sites. A promising way to reduce storage space and disposal cost is by first converting the actinide species in the waste salts to oxides through oxygen sparging and then separating the salts from the actinides via a vacuum evaporation process. The separation is possible because of the large difference in the vapor pressure between the chloride salts and the actinide oxides. To aid the optimization of this evaporation separation process and process equipment design, an effort to model the evaporation-condensation process of molten KCl-NaCl solutions was initiated. This article presents the first part of the modeling work in developing vapor pressure relations of the KCl-NaCl system. The methodology of using fundamental thermodynamic relations and data to model the vapor pressure equations for the solid and liquid solutions of the KCl-NaCl system will be presented, and the vapor pressures calculated from the model equation will be compared with the available experimental data. How the model equations are useful in predicting condensate compositions will also be discussed.

Wang, L.L.; Wallace, T.C. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

1996-02-01

429

Material transport regimes and mechanisms for growth of molecular organic thin films using low-pressure organic vapor phase deposition  

Microsoft Academic Search

We determine the physical mechanisms controlling the growth of amorphous organic thin films by the process of low-pressure organic vapor phase deposition (LP-OVPD). In LP-OVPD, multiple host and dopant molecular sources are introduced into a hot wall reactor via several injection barrels using an inert carrier gas, allowing for controlled film growth rates exceeding 10 \\/s. The temperature and carrier

Max Shtein; Herman F. Gossenberger; Jay B. Benziger; Stephen R. Forrest

2001-01-01

430

Selective epitaxial growth of silicon-germanium by a tubular hot-wall low pressure chemical vapor deposition system  

Microsoft Academic Search

The goal of this study is to obtain fundamental process-property relationships for the SiGe epitaxial growth and from such knowledge to assemble a tubular hot-wall low pressure chemical vapor deposition system capable of producing selective epitaxial SiGe films. This is the very first report of such an attempt by any research group to produce epitaxial SiGe films using this type

I-Ming Lee

1997-01-01

431

High-pressure vapor-liquid equilibrium of some binary mixtures of cyclopentane, argon, nitrogen, n-butane, and neopentane  

SciTech Connect

In this paper, accurate high-pressure vapor-liquid equilibrium and phase density data for binary systems of cyclopentane with carbon dioxide, nitrogen, and argon and of argon also with neopentane and n-butane are reported, each at two isotherms. These data are correlated with the Peng-Robinson equation of state using one- and two-parameter versions of the van der Waals one-fluid mixing rules with both generalized and fluid-specific equation of state parameters.

Marathe, P.; Sandler, S.I. (Delaware Univ., Newark, DE (United States). Dept. of Chemical Engineering)

1991-04-01

432

Low temperature atmospheric pressure chemical vapor deposition of group 14 oxide films  

SciTech Connect

Depositions of high quality SiO{sub 2} and SnO{sub 2} films from the reaction of homoleptic amido precursors M(NMe{sub 2})4 (M = Si,Sn) and oxygen were carried out in an atmospheric pressure chemical vapor deposition r. The films were deposited on silicon, glass and quartz substrates at temperatures of 250 to 450C. The silicon dioxide films are stoichiometric (O/Si = 2.0) with less than 0.2 atom % C and 0.3 atom % N and have hydrogen contents of 9 {plus_minus} 5 atom %. They are deposited with growth rates from 380 to 900 {angstrom}/min. The refractive indexes of the SiO{sub 2} films are 1.46, and infrared spectra show a possible Si-OH peak at 950 cm{sup {minus}1}. X-Ray diffraction studies reveal that the SiO{sub 2} film deposited at 350C is amorphous. The tin oxide films are stoichiometric (O/Sn = 2.0) and contain less than 0.8 atom % carbon, and 0.3 atom % N. No hydrogen was detected by elastic recoil spectroscopy. The band gap for the SnO{sub 2} films, as estimated from transmission spectra, is 3.9 eV. The resistivities of the tin oxide films are in the range 10{sup {minus}2} to 10{sup {minus}3} {Omega}cm and do not vary significantly with deposition temperature. The tin oxide film deposited at 350C is cassitterite with some (101) orientation.

Hoffman, D.M. [Houston Univ., TX (United States); Atagi, L.M. [Houston Univ., TX (United States)]|[Los Alamos National Lab., NM (United States); Chu, Wei-Kan; Liu, Jia-Rui; Zheng, Zongshuang [Houston Univ., TX (United States); Rubiano, R.R. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Springer, R.W.; Smith, D.C. [Los Alamos National Lab., NM (United States)

1994-06-01

433

Vapor pressures in the ternary system water-nitric acid-sulfuric acid at low temperature: A reexamination  

NASA Astrophysics Data System (ADS)

The equilibrium partial vapor pressures over the binary solutions H2O/HNO3, H2SO4/H2O, HNO3/H2SO4 and the ternary mixture H2SO4/HNO3/H2O have been re-determined for temperatures below 25C. The model presented here is valid over the entire range of concentrations, for temperatures in the range 190-298 K. The predictions of this model are compared with the existing measurements and other predictions, both at room temperature and at low temperatures down to about 190 K. The calculated partial pressures agree very well with the available experimental data

Taleb, Djamel-Eddine; Ponche, Jean-Luc; Mirabel, Philippe

1996-11-01

434

Rapid thermal low-pressure metal organic chemical vapor deposition of Fe-doped InP layers  

NASA Astrophysics Data System (ADS)

High quality Fe-doped InP layers have been grown by means of rapid thermal low-pressure metal organic chemical vapor deposition. Trimethylindium, tertiarybutylphosphine, and ferrocene were used as indium, phosphorus, and iron sources, respectively. The best growth conditions are: V-III ratio of 100 temperature of 650 C, pressure of 4 Torr and growth rate of 2 ?m/h. Featureless films were grown with a flat iron concentration of 21018 cm-3 as a function of depth, with an average specific resistivity of 108 ? cm and a narrow x-ray half-maximum peak of 15 arcs.

Kreinin, O.; Bahir, G.

2002-01-01

435

Effects of capillarity and vapor adsorption in the depletion of vapor-dominated geothermal reservoirs  

SciTech Connect

Vapor-dominated geothermal reservoirs in natural (undisturbed) conditions contain water as both vapor and liquid phases. The most compelling evidence for the presence of distributed liquid water is the observation that vapor pressures in these systems are close to saturated vapor pressure for measured reservoir temperatures (White et al., 1971; Truesdell and White, 1973). Analysis of natural heat flow conditions provides additional, indirect evidence for the ubiquitous presence of liquid. From an analysis of the heat pipe process (vapor-liquid counterflow) Preuss (1985) inferred that effective vertical permeability to liquid phase in vapor-dominated reservoirs is approximately 10{sup 17} m{sup 2}, for a heat flux of 1 W/m{sup 2}. This value appears to be at the high end of matrix permeabilities of unfractured rocks at The Geysers, suggesting that at least the smaller fractures contribute to liquid permeability. For liquid to be mobile in fractures, the rock matrix must be essentially completely liquid-saturated, because otherwise liquid phase would be sucked from the fractures into the matrix by capillary force. Large water saturation in the matrix, well above the irreducible saturation of perhaps 30%, has been shown to be compatible with production of superheated steam (Pruess and Narasimhan, 1982). In response to fluid production the liquid phase will boil, with heat of vaporization supplied by the reservoir rocks. As reservoir temperatures decline reservoir pressures will decline also. For depletion of ''bulk'' liquid, the pressure would decline along the saturated vapor pressure curve, while for liquid held by capillary and adsorptive forces inside porous media, an additional decline will arise from ''vapor pressure lowering''. Capillary pressure and vapor adsorption effects, and associated vapor pressure lowering phenomena, have received considerable attention in the geothermal literature, and also in studies related to geologic disposal of heat generating nuclear wastes, and in the drying of porous materials. Geothermally oriented studies were presented by Chicoine et al. (1977), Hsieh and Ramey (1978, 1981), Herkelrath et al. (1983), and Nghiem and Ramey (1991). Nuclear waste-related work includes papers by Herkelrath and O'Neal (1985), Pollock (1986), Eaton and Bixler (1987), Pruess et al. (1990), Nitao (1990), and Doughty and E'ruess (1991). Applications to industrial drying of porous materials have been discussed by Hamiathy (1969) arid Whitaker (1977). This paper is primarily concerned with evaluating the impact of vapor pressure lowering (VPL) effects on the depletion behavior of vapor-dominated reservoirs. We have examined experimental data on vapor adsorption and capillary pressures in an effort to identify constitutive relationships that would be applicable to the tight matrix rocks of vapor-dominated systems. Numerical simulations have been performed to evaluate the impact of these effects on the depletion of vapor-dominated reservoirs.

Pruess, Karsten; O'Sullivan, Michael

1992-01-01

436

On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.  

SciTech Connect

Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The complexity of these systems, which involve chemical reactions in both the gas phase and on the deposition surface, as well as complex fluid dynamics, makes process optimization and design of new coating reactors a very difficult task. In 2001 the U.S. Dept. of Energy Industrial Technologies Program Glass Industry of the Future Team funded a project to address the need for more accurate data concerning the tin oxide APCVD process. This report presents a case study of on-line APCVD using organometallic precursors, which are the primary reactants used in industrial coating processes. Research staff at Sandia National Laboratories in Livermore, CA, and the PPG Industries Glass Technology Center in Pittsburgh, PA collaborated to produce this work. In this report, we describe a detailed investigation of the factors controlling the growth of tin oxide films. The report begins with a discussion of the basic elements of the deposition chemistry, including gas-phase thermochemistry of tin species and mechanisms of chemical reactions involved in the decomposition of tin precursors. These results provide the basis for experimental investigations in which tin oxide growth rates were measured as a function of all major process variables. The experiments focused on growth from monobutyltintrichloride (MBTC) since this is one of the two primary precursors used industrially. There are almost no reliable growth-rate data available for this precursor. Robust models describing the growth rate as a function of these variables are derived from modeling of these data. Finally, the results are used to conduct computational fluid dynamic simulations of both pilot- and full-scale coating reactors. As a result, general conclusions are reached concerning the factors affecting the growth rate in on-line APCVD reactors. In addition, a substantial body of data was generated that can be used to model many different industrial tin oxide coating processes. These data include the most extensive compilation of thermochemistry for gas-phase tin-containing species as well as kinetic expressions describing tin oxide growth rates over a wide range of temperatures, pressures, and reactant concentrations.

Allendorf, Mark D.; Sopko, J.F. (PPF Industries, Pittsburgh, PA); Houf, William G.; Chae, Yong Kee; McDaniel, Anthony H.; Li, M. (PPF Industries, Pittsburgh, PA); McCamy, J.W. (PPF Industries, Pittsburgh, PA)

2006-11-01

437

Oxygen pressure measurements of silica saturated Fe-O-SiO2 melts by the EMF method using zirconia solid electrolyte  

NASA Astrophysics Data System (ADS)

The thermodynamic properties of silica-saturated iron silicate slags have been studied from oxygen partial pressure measurements using a solid electrolyte galvanic cell. The oxygen activity in molten silver bath equilibrated with iron silicate slags was determined by the following cell type, Pt, NiNiOJO= /slag-Ag(O), LaCrO3, Pt at temperatures between 1473 and 1573 K for the slags ranging in compositions from iron saturation to magnetite saturation. The oxygen partial pressures obtained in this investigation were in good agreement with those given by the previous study using the CO-CO2 gas equilibrium method. The data showed that the Fe+ ++/Fe++ ratio is proportional toP_{O_2 }^{1/4}.

Oishi, Toshio; Goto, Tetsuya; Kayahara, Yoshiro; Ono, Katsutoshi; Moriyama, Joichiro

1991-12-01

438

Oxygen pressure measurements of silica saturated Fe-O-SiO2 melts by the emf method using zirconia solid electrolyte  

NASA Astrophysics Data System (ADS)

The thermodynamic properties of silica-saturated iron silicate slags have been studied from oxygen partial pressure measurements using a solid electrolyte galvanic cell. The oxygen activity in molten silver bath equilibrated with iron silicate slags was determined by the following cell type, Pt, Ni-NiO/O=/slag-Ag(O), LaCrO3, Pt at temperatures between 1473 and 1573 K for the slags ranging in compositions from iron saturation to magnetite saturation. The oxygen partial pressures obtained in this investigation were in good agreement with those given by the previous study using the CO-CO2 gas equilibrium method. The data showed that the Fe+++/Fe++ ratio is proportional to P o 2

Oishi, Toshio; Goto, Tetsuya; Kayahara, Yoshiro; Ono, Katsutoshi; Moriyama, Joichiro

1982-09-01

439

Water saturated phase relations of some andesites with application to the estimation of the initial temperature and water pressure at the time of eruption  

Microsoft Academic Search

Near-liquidus phase relations in one-atmosphere dry and water-saturated high pressure conditions were experimentally determined on products of three historic andesitic eruptions. Run conditions ranged from 900 to 1100C, at pressures up to 1500 bars with fO 2 controlled close to the nickel-nickel oxide (NNO) buffer. In order to represent the compositions of the true liquid parts of the erupting magmas,

Toshimori Sekine; Takashi Katsura; Shigeo Aramaki

1979-01-01

440

The dissolution of calcite in CO2-saturated solutions at 25??C and 1 atmosphere total pressure  

USGS Publications Warehouse

The dissolution of Iceland spar in CO2-saturated solutions at 25??C and 1 atm total pressure has been followed by measurement of pH as a function of time. Surface concentrations of reactant and product species have been calculated from bulk fluid data using mass transport theory and a model that accounts for homogeneous reactions in the bulk fluid. The surface concentrations are found to be close to bulk solution values. This indicates that calcite dissolution under the experimental conditions is controlled by the kinetics of surface reaction. The rate of calcite dissolution follows an empirical second order relation with respect to calcium and hydrogen ion from near the initial condition (pH 3.91) to approximately pH 5.9. Beyond pH 5.9 the rate of surface reaction is greatly reduced and higher reaction orders are observed. Calculations show that the rate of calcite dissolution in natural environments may be influenced by both transport and surface-reaction processes. In the absence of inhibition, relatively short times should be sufficient to establish equilibrium. ?? 1976.

Plummer, L. N.; Wigley, T. M. L.

1976-01-01

441

Temperature and Water Vapor Pressure Effects on the Friction Coefficient of Hydrogenated Diamondlike Carbon Films.  

National Technical Information Service (NTIS)

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior th...

A. Erdemir N. Argibay O. L. Eryilmaz P. L. Dickrell W. G. Sawyer

2009-01-01

442

Vapor-liquid equilibrium in low pressure water+congener mixtures  

Microsoft Academic Search

Vapor-liquid equilibrium in binary water+congeners mixtures found in alcoholic distillation has been analyzed using the Peng-Robinson\\u000a equation of state and one of the most popular modern mixing rules, the Wong-Sandler model. Accurate modeling of the concentration\\u000a of congeners (substances different from ethanol and water) in the vapor phase is of special importance because these substances\\u000a give some special characteristics of

Claudio Alonso Fandez; Felipe Andrs Urbina; Jos Omar Valderrama

2009-01-01

443

Comparative Study of Equilibrium and Nonequilibrium Evaporation Models for Vaporizing Droplet Arrays at High-Pressure  

Microsoft Academic Search

Combustion performances and emissions are mainly influenced by atomization, evaporation of fuel droplets and mixing of fuel\\u000a and air. In particular, vaporization is often the rate-controlling process and is directly related to the specific fuel consumption\\u000a of the engine and to pollutant formation. The present work focuses on two competing factors, which strongly influence the\\u000a vaporization process, specifically: dropdrop interactions

Grazia Lamanna; H. Sun; M. Schler; B. Weigand; D. Magatti; F. Ferri

444

Correlation of retention times on liquid crystal capillary column with reported vapor pressures and half-lives of compounds used in pheromone formulations  

Microsoft Academic Search

A method has been developed to determine by capillary gas chromatography on liquid crystal stationary phases the relative vapor pressures and half-lives of many compounds used as insect pheromones. This study demonstrated that the retention time of seven acetates on a liquid crystal column (cholesteryl-p-chlorocinnamate) could be correlated closely to the reported vapor pressures of the compounds. For 13 additional

R. R. Heath; J. H. Tumlinson

1986-01-01

445

Near-IR absorption of water vapor: Pressure dependence of line strengths and an upper limit for continuum absorption  

NASA Astrophysics Data System (ADS)

Water vapor absorption cross-sections in the near-infrared region (10 500-10 800 cm-1) were measured using cavity ringdown spectroscopy. Linestrengths were measured for several absorption lines around 10 604 cm-1 (943 nm) between 500 and 850 Torr of N2 and found to be independent of pressure. Our measured linestrengths of these individual lines agree well with values from databases such as HITRAN and the ESA-WVR, which are currently used for atmospheric calculations, but the integrated strength over the entire measured spectral region is slightly larger than that contained in these databases. Water vapor pressure-broadening coefficients due to nitrogen were also estimated from these measurements. The absorption due to water vapor continuum was determined to be less than (9.2 0.2) 10-27 cm2 molecule-1 at 11 500 cm-1. This measured upper limit, though larger than the estimated values from continuum models, would not contribute significantly to the calculated radiation absorption in this wavelength region.

Aldener, M.; Brown, S. S.; Stark, H.; Daniel, J. S.; Ravishankara, A. R.

2005-08-01

446

A combined droplet train and ambient pressure photoemission spectrometer for the investigation of liquid/vapor interfaces  

SciTech Connect

We describe a combined ambient pressure photoelectron spectroscopy/droplet train apparatus for investigating the nature and heterogeneous chemistry of liquid/vapor interfaces. In this instrument a liquid droplet train with typical droplet diameters from 50...150 {micro}m is produced by a vibrating orifice aerosol generator (VOAG). The droplets are irradiated by soft X-rays (100...1500 eV) in front of the entrance aperture of a differentially pumped electrostatic lens system that transfers the emitted electrons into a conventional hemispherical electron analyzer. The photoemission experiments are performed at background pressures of up to several Torr, which allows the study of environmentally important liquid/vapor interfaces, in particular aqueous solutions, under equilibrium conditions. The exposure time of the droplet surface to the background gases prior to the XPS measurement can be varied, which will allow future kinetic measurements of gas uptake on liquid surfaces. As an example, a measurement of the surface composition of a {chi} = 0.21 aqueous methanol solution is presented. The concentration of methanol at the vapor/liquid interface is enhanced by a factor of about 3 over the bulk value, while the expected bulk value is recovered at depths larger than about 1.5 nm.

Starr, David E.; Wong, Ed K.; Worsnop, Douglas R.; Wilson, Kevin R.; Bluhm, Hendrik

2008-05-01

447

Liquid phase growth of bulk GaSe crystal implemented with the temperature difference method under controlled vapor pressure  

NASA Astrophysics Data System (ADS)

GaSe crystal has been expected as one of the promising nonlinear optical crystals for highly efficient terahertz (THz) wave generation. However there are several reasons why it is difficult to grow the bulk crystals with high quality. To overcome some difficulties, the temperature difference method under controlled vapor pressure (TDM-CVP) is applied for crystal growth. According to this method, stoichiometric composition can be controlled by the application of Se vapor during crystal growth. Crystal growth is carried out at a constant growth temperature without any mechanical disturbance or vibration. It is also noticed that lower temperature growth enables the reduction of point defect concentration in equilibrium. In this article, surface morphology is observed by an optical microscope using the Nomarski interference method. To identify polytypes of grown crystals, backscattered Raman spectra were measured. X-ray diffraction confirmed the polytypes and single crystalline phase. Infrared (?=1 ?m) and terahertz wave (13 THz) transmittance measurements were performed to calculate the absorption coefficient in these wavelength regions. From these results, it is shown that the grown crystals have shown ?-type single phase and the absorption coefficients of grown crystals have been improved according to the increase of applied Se vapor pressure during crystal growth.

Onai, Takahide; Nagai, Yuki; Dezaki, Hikari; Oyama, Yutaka

2013-10-01

448

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics  

NASA Astrophysics Data System (ADS)

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 pressure 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 pressure 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 pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor 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.

Makarieva, A. M.; Gorshkov, V. G.; Sheil, D.; Nobre, A. D.; Li, B.-L.

2013-01-01

449

Measurements of seismic attenuation and transient fluid pressure in partially saturated Berea sandstone: evidence of fluid flow on the mesoscopic scale  

NASA Astrophysics Data System (ADS)

A novel laboratory technique is proposed to investigate wave-induced fluid flow on the mesoscopic scale as a mechanism for seismic attenuation in partially saturated rocks. This technique combines measurements of seismic attenuation in the frequency range from 1 to 100 Hz with measurements of transient fluid pressure as a response of a step stress applied on top of the sample. We used a Berea sandstone sample partially saturated with water. The laboratory results suggest that wave-indu