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1

Isobaric vapor-liquid equilibrium for ethanol + water + potassium nitrate  

Microsoft Academic Search

An increasing research interest in the determination of the salt effect in the vapor-liquid equilibrium of binary systems has developed over the last few decades due to the importance of distillation with salts in the separation of close boiling and azeotropic mixtures. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt

Ernesto Vercher; M. Pilar Peña; Antoni Martinez-Andreu

1996-01-01

2

Isobaric vapor-liquid equilibrium for ethanol + water + strontium nitrate  

Microsoft Academic Search

The effect of salts on the vapor-liquid equilibrium of solvent mixtures is of considerable interest in the separation of close boiling and azeotropic mixtures. The salt effect has been studied by many researchers. Most investigations have been limited to measurements on the saturated salt solutions. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + strontium nitrate (3) at various

Ernesto Vercher; M. Pilar Peña; Antoni Martinez-Andreu

1996-01-01

3

Isobaric vapor-liquid equilibrium for ethanol + water + sodium nitrate  

Microsoft Academic Search

The salt effect on the vapor-liquid equilibrium of mixed solvents provides a potential technique of extractive distillation, in which a dissolved salt, rather than a liquid additive, is used as the separating agent. This salt distillation process has been used in the purification of close-boiling, azeotropic, and other systems which are difficult to separate. The isobaric vapor-liquid equilibrium for ethanol

M. Pilar Peña; Ernesto Vercher; Antoni Martinez-Andreu

1996-01-01

4

Isobaric vapor-liquid equilibrium for ethanol + water + potassium nitrate  

SciTech Connect

An increasing research interest in the determination of the salt effect in the vapor-liquid equilibrium of binary systems has developed over the last few decades due to the importance of distillation with salts in the separation of close boiling and azeotropic mixtures. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.642 has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.

Vercher, E.; Pena, M.P.; Martinez-Andreu, A. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1996-01-01

5

Isobaric vapor-liquid equilibrium for ethanol + water + strontium nitrate  

SciTech Connect

The effect of salts on the vapor-liquid equilibrium of solvent mixtures is of considerable interest in the separation of close boiling and azeotropic mixtures. The salt effect has been studied by many researchers. Most investigations have been limited to measurements on the saturated salt solutions. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + strontium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.672, has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.

Vercher, E.; Pena, M.P.; Martinez-Andreu, A. [Univ. de Valencia (Spain)

1996-07-01

6

Isobaric vapor-liquid equilibrium data for the ethanol-water-strontium bromide system  

SciTech Connect

Isobaric experimental data of vapor-liquid equilibrium for the ethanol-water-strontium bromide system at different mole fractions of strontium bromide have been measured at 100.6 kPa. Data were correlated by Jaques and Furter's method. Thermodynamic consistency was checked by Herington's method with satisfactory results.

Vercher, E.; Pena, M.P.; Martinez-Andreu, A. (Univ. de Valencia (Spain). Dept. de Ingenieria Quimica)

1994-04-01

7

Isobaric vapor-liquid equilibrium for methyldichlorosilane-dimethyldichlorosilane-benzene system  

Microsoft Academic Search

The elucidation of vapor-liquid equilibrium (VLE) of the halogenated silane was necessary for the production of silicon derivatives,\\u000a especially for methylvinyldichlorosilane, due to the lack of the relevant reports. Isobaric VLE for the system methyldichlorosilane-dimethyldichlorosilane-benzene\\u000a and isobaric VLE of the three binary systems were measured with a new pump-ebulliometer at the pressure of 101.325 kPa. These\\u000a binary compositions of the

Qiu Zu-min; Xie Xin-liang; Yu Shu-xian; Chen Wen-you; Xie Feng-xia; Liu Juan

2005-01-01

8

Quaternary isobaric (vapor + liquid + liquid) equilibrium and (vapor + liquid) equilibrium for the system (water + ethanol + cyclohexane + heptane) at 101.3 kPa  

Microsoft Academic Search

Experimental isobaric (vapor+liquid+liquid) and (vapor+liquid) equilibrium data for the ternary system {water (1)+cyclohexane (2)+heptane (3)} and the quaternary system {water (1)+ethanol (2)+cyclohexane (3)+heptane (4)} were measured at 101.3kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by

Ana Pequenín; Juan Carlos Asensi; Vicente Gomis

2011-01-01

9

Isobaric vapor-liquid equilibrium for ethanol + water + copper(II) chloride  

Microsoft Academic Search

The extractive distillation in which an electrolyte is employed as the extractive agent is an important alternative to the conventional methods for separating mixtures involving azeotropes. Isobaric vapor-liquid equilibrium for ethanol (1) + water(2) + copper(II) chloride (3) at different mole fractions of copper(II) chloride has been measured at 100.0 kPa. The results in the range where the mole fraction

Ernesto Vercher; M. Pilar Pena; Antoni Martinez-Andreu

1995-01-01

10

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+methyl ethyl ketone (MEK), MEK+isopropyl acetate, acetic acid+MEK+water and acetic acid+MEK+isopropyl acetate+water are measured at 101.33kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in

Qiang Xie; Hui Wan; MingJuan Han; GuoFeng Guan

2009-01-01

11

Isobaric vapor-liquid equilibrium for ethanol + water + copper(II) chloride  

SciTech Connect

The extractive distillation in which an electrolyte is employed as the extractive agent is an important alternative to the conventional methods for separating mixtures involving azeotropes. Isobaric vapor-liquid equilibrium for ethanol (1) + water(2) + copper(II) chloride (3) at different mole fractions of copper(II) chloride has been measured at 100.0 kPa. The results in the range where the mole fraction of salt in the liquid phase was less than 0.146 times the mole fraction of water were correlated by assuming that the salt was in ionic form and it was associated only with the water. Thermodynamic consistency was checked according to Herington`s method with satisfactory results.

Vercher, E.; Pena, M.P.; Martinez-Andreu, A. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1995-05-01

12

Isobaric vapor-liquid equilibrium of the systems cumene + benzyl alcohol and phenol + benzyl alcohol at 10 kPa  

Microsoft Academic Search

Isobaric vapor-liquid equilibrium data are reported for the binary systems cumene + benzyl alcohol and phenol + benzyl alcohol at 10 kPa. The activity coefficient data were tested for thermodynamic consistency by the methods of Herington, Black, and Van Ness and correlated with the Wilson equation. None of the systems show an azeotrope.

Jose M. Resa; Teresita Quintana; Emilio Cepeda

1994-01-01

13

Isobaric vapor–liquid equilibrium of systems containing triethyl orthoformate at 101.3 kPa  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium data of ethanol(1)-triethyl orthoformate(2), benzene(1)-triethyl orthoformate(2) and ethanol(1)-benzene(2)-triethyl orthoformate(3) were measured at 101.3 kPa and under a wide range of temperatures (349–420 K), using the Rose–Williams still modified by the authors. The experimental data of binary systems were tested for thermodynamic consistency with the method of Fredenslund and coworkers and correlated satisfactorily with SRK equation and PR

Zhong-Xiu Chen; Wang-Ming Hu; Jian-Gang Lu; Xue-Min Li

1999-01-01

14

Vapor–liquid–liquid equilibrium and vapor–liquid equilibrium for the quaternary system water–ethanol–cyclohexane–toluene and the ternary system water–cyclohexane–toluene. Isobaric experimental determination at 101.3 kPa  

Microsoft Academic Search

Experimental isobaric vapor–liquid–liquid and vapor–liquid equilibrium data for the ternary system water (1)–cyclohexane (2)–toluene (3) and the quaternary system water (1)–ethanol (2)–cyclohexane (3)–toluene (4) were measured at 101.3kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by

Ana Pequenín; Juan Carlos Asensi; Vicente Gomis

2011-01-01

15

Salt effect on the isobaric vapor-liquid equilibrium of the methyl acetate + methanol system  

Microsoft Academic Search

The effect of sodium thiocyanate at constant salt mole fraction from 0.01 to 0.05 and at saturation on the vapor-liquid equilibrium (VLE) of methyl acetate + methanol has been studied at 101.32 kPa using a modified Othmer equilibrium still. The salt exhibited both salting-in and salting-out effects on the methyl acetate, the azeotrope being eliminated at saturation. The results were

Maria C. Iliuta; Fernand C. Thyrion; Ortansa M. Landauer

1996-01-01

16

Effect of calcium chloride on the isobaric vapor-liquid equilibrium of 1-propanol + water  

Microsoft Academic Search

The effect of calcium chloride at salt mole fractions from 0.02 to saturation on the vapor-liquid equilibrium (VLE) of 1-propanol + water has been studied at 101.32 kPa using a modified Othmer equilibrium still. The salt exhibited a salting-out effect of the alcohol over the whole range of liquid composition, the azeotrope being eliminated at salt mole fractions greater than

Maria C. Iliuta; Fernand C. Thyrion; Ortansa M. Landauer

1996-01-01

17

Salt effect on the isobaric vapor-liquid equilibrium of the methyl acetate + methanol system  

SciTech Connect

The effect of sodium thiocyanate at constant salt mole fraction from 0.01 to 0.05 and at saturation on the vapor-liquid equilibrium (VLE) of methyl acetate + methanol has been studied at 101.32 kPa using a modified Othmer equilibrium still. The salt exhibited both salting-in and salting-out effects on the methyl acetate, the azeotrope being eliminated at saturation. The results were correlated using the extended UNIQUAC model of Sander et al. and the electrolytic NRTL model of Mock et al.

Iliuta, M.C.; Thyrion, F.C. [Louvain Univ., Louvain-la-Neuve (Belgium). Chemical Engineering Inst.; Landauer, O.M. [Univ. Politehnica Bucharest (Romania)

1996-07-01

18

Experimental study of miscibility, density and isobaric vapor-liquid equilibrium values for mixtures of methanol in hydrocarbons (C5, C6)  

Microsoft Academic Search

Isobaric vapor-liquid equilibrium data at 141.3 kPa for the mixtures of methanol with n-pentane and n-hexane are reported. The miscibility of methanol + n-hexane is also measured in order to get the UCSP (upper critical solubility point), then the experimental curves of vE are obtained at temperatures with total miscibility. The equilibrium data are correlated with different equations and the

Ana Maria Blanco; Juan Ortega

1996-01-01

19

Isobaric Vapor-Liquid Equilibrium in the Systems Ethyl 1,1-Dimethylethyl Ether + 2,2,4Trimethylpentane and + Octane  

Microsoft Academic Search

Consistent vapor-liquid equilibrium data for the binary systems ethyl 1,1-dimethylethyl ether (ETBE) + 2,2,4-trimethylpentane and ethyl 1,1-dimethylethyl ether + octane at 94 kPa, including pure component vapor pressures of 2,2,4-trimethylpentane and octane, have been experimentally determined. the measured systems deviate slightly from ideal behavior, can be described as symmetric regular solutions and present no azeotropes. Boiling points were correlated using

Jaime Wisniak; Graciela Galindo; Ricardo Reich; Hugo Segura

1999-01-01

20

Program performs vapor-liquid equilibrium calculations  

Microsoft Academic Search

A program designed for the Hewlett-Packard HP-41CV or 41C calculators solves basic vapor-liquid equilibrium problems, including figuring the dewpoint, bubblepoint, and equilibrium flash. The algorithm uses W.C. Edmister's method for predicting ideal-solution K values.

1982-01-01

21

Program performs vapor-liquid equilibrium calculations  

SciTech Connect

A program designed for the Hewlett-Packard HP-41CV or 41C calculators solves basic vapor-liquid equilibrium problems, including figuring the dewpoint, bubblepoint, and equilibrium flash. The algorithm uses W.C. Edmister's method for predicting ideal-solution K values.

Rice, V.L.

1982-06-28

22

Prediction of thermodynamic, transport and vapor–liquid equilibrium properties of binary mixtures of ethylene glycol and water  

Microsoft Academic Search

Equilibrium and non-equilibrium molecular dynamics and Monte Carlo simulation techniques were applied to predict various thermodynamic, transport and vapor–liquid equilibrium properties of binary mixtures of ethylene glycol and water (EG–W) based on OPLS-AA and SPC\\/E force fields. The properties predicted include density, vaporization enthalpy, enthalpy of mixing, heat capacities, diffusion coefficients, shear viscosities, thermal conductivities, vapor–liquid coexistence isotherms and isobaric

Jianxing Dai; Ling Wang; Yingxin Sun; Lin Wang; Huai Sun

2011-01-01

23

Vapor-liquid equilibrium calculations for polymer solutions  

Microsoft Academic Search

Bonner's theory for the prediction of vapor-liquid equilibria of polymer solutions has been modified. A new equation of state and corresponding vapor-liquid equilibrium equation are proposed. Good results have been obtained for mixtures of nonpolar and moderately polar compounds, containing polymers and subcritical or supercritical solvents. Predictions can be based on a single measurement of the infinite dilution activity coefficient

William Schotte

1982-01-01

24

Optimization of activity coefficient models to describe vapor-liquid equilibrium of (alcohol + water) mixtures using a particle swarm algorithm  

Microsoft Academic Search

A method to model the vapor–liquid phase based on a particle swarm algorithm is developed in this study. Two activity coefficient models (UNIQUAC and NRTL) were optimized with particle swarm optimization (PSO), and used to describe the isobaric vapor–liquid equilibrium of fifteen binary mixtures containing alcohol + water. The results were compared with the Levenberg–Marquardt algorithm, and show that the PSO algorithm

Juan A. Lazzús

2010-01-01

25

Molecular thermodynamics of salt effect in vapor–liquid equilibrium of ethanol–water systems  

Microsoft Academic Search

Scaled particle theory was used to derive a general expression for the salt effect parameter, K, of isobaric vapor–liquid equilibrium for ethanol–water-1-1 type electrolytic systems, which appears in the Furter equation. This expression was essentially a sum of two terms: 1, the hard sphere interaction term calculated by Masterton–Lee's equation, 2, the soft sphere interaction term calculated by Y. Hu's

Ren Yi Sun

1999-01-01

26

A "User-Friendly" Program for Vapor-Liquid Equilibrium.  

ERIC Educational Resources Information Center

|Described is a computer software package suitable for teaching and research in the area of multicomponent vapor-liquid equilibrium. This program, which has a complete database, can accomplish phase-equilibrium calculations using various models and graph the results. (KR)|

Da Silva, Francisco A.; And Others

1991-01-01

27

Vapor-liquid equilibrium measurements on five binary mixtures  

Microsoft Academic Search

Vapor-liquid equilibrium measurements have been made on five binary mixtures. The systems were chosen in order to provide insight into specific group interactions. Each of the systems was studied at two temperatures across the entire composition range. The PTx method, which is a fast, reliable means of obtaining VLE data, was used on each system. One of the systems was

W. V. Wilding; L. C. Wilson; G. M. Wilson

1987-01-01

28

Modification of the Furter equation and correlation of the vapor–liquid equilibrium for mixed-solvent electrolyte systems  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium values at 1 atm pressure were measured for the systems 1-propanol–water–potassium acetate and 2-propanol–water–potassium acetate under fixed salt mole fractions using a modified Othmer recirculation still. A modified Furter equation, ln(?s\\/?)=k1z+k2z2, was proposed for correlating the effect of dissolved salts on vapor–liquid equilibrium (VLE). The modified equation contains two parameters that are applicable to the entire salt\\/solvent

W. L. Wu; Y. M. Zhang; X. H. Lu; Y. R. Wang; J. Shi; Benjamin C.-Y. Lu

1999-01-01

29

Thermodynamic study on binary mixtures of propyl ethanoate and an alkan-1-ol (C 2–C 4). Isobaric vapor–liquid equilibria and excess properties  

Microsoft Academic Search

This paper presents an analysis on binary mixtures of propyl ethanoate and an alkan-1-ol (ethanol to butanol) using the results obtained for different thermodynamic quantities such as the isobaric vapor–liquid equilibrium (VLE) data at pressures of 101.3 kPa and 160.0 kPa, excess enthalpies and excess volumes. Vapor pressures for the same normal alkanols used, determined using the same equilibrium still,

Juan Ortega; Carmelo Gonzalez; Juan Peña; Salvador Galván

2000-01-01

30

Isobaric vapor–liquid equilibria for the quaternary reactive system: Ethanol + water + ethyl lactate + lactic acid at 101.33 kPa  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data of the reactive quaternary system ethanol (1)+water (2)+ethyl lactate (3)+lactic acid (4) have been determined experimentally. Additionally, the reaction equilibrium constant was calculated for each VLE experimental data. The experimental VLE data were correlated using the UNIQUAC equation to describe the chemical and phase equilibria simultaneously. For some of the non-reactive binary systems, UNIQUAC binary

Patricia Delgado; María Teresa Sanz; Sagrario Beltrán

2007-01-01

31

Thermodynamic properties of the LiCl–H 2O system at vapor–liquid equilibrium from 273 K to 400 K  

Microsoft Academic Search

A formulation of the thermodynamic properties of the LiCl–H2O system at vapor–liquid equilibrium is presented in the form of separate Gibbs energy equations for the vapor and solution phases. Explicit thermodynamically consistent equations for density, isobaric heat capacity, enthalpy, entropy, enthalpy of dilution and osmotic coefficient are given. The pressure at vapor–liquid equilibrium is calculated from the condition of phase

J. Pátek; J. Klomfar

2008-01-01

32

Isobaric vapor-liquid equilibria of octane + 1-butanol, + 2-butanol, and + 2-methyl-2-propanol at 101.3 kPa  

Microsoft Academic Search

Isobaric vapor-liquid equilibria were measured for three binary systems of 1-butanol + octane, 2-butanol + octane, and 2-methyl-2-propanol + octane at 101.3 kPa. The measurements were made in an equilibrium still with circulation of both the vapor and liquid phases. Both 1-butanol + octane and 2-butanol + octane form a minimum boiling azeotrope. 2-Methyl-2-propanol + octane is a nonazeotrope. The

Toshihiko Hiaki; Akira Taniguchi; Tomoya Tsuji; Masaru Hongo; Kazuo Kojima

1996-01-01

33

Isobaric Vapor?Liquid Equilibria and Excess Volumes for the Binary Mixtures Water + Sulfolane, Water + Tetraethylene Glycol, and Benzene + Tetraethylene Glycol  

Microsoft Academic Search

Isobaric vapor-liquid equilibrium data were determined at 101.33 kPa for the binary mixtures of water + sulfolane and water + tetraethylene glycol. Calculations of the nonideality of the vapor phase were made with the second virial coefficients obtained from the Hayden-O'Connell method. The boiling points and vapor-phase compositions reported were well correlated by the Wilson, NRTL, and UNIQUAC models. In

Yang-Xin Yu; Jian-Gang Liu; Guang-Hua Gao

2000-01-01

34

Vapor-liquid equilibrium measurements and data analysis of tert-butanol?isobutanol and tert-butanol?water binaries at 94.9 kPa  

Microsoft Academic Search

Isobaric vapor-liquid equilibrium (VLE) data were measured for the systems tert-butanol-isobutanol and tert-butanol?water at 94.9 kPa using a modified Malanowski equilibrium still. While the experimental data of the former binary showed a slight deviation from ideality, the latter binary showed a significant deviation. The experimental data of this work, in addition to two isobaric VLE data sets from the literature,

Naif A. Darwish; Zaid A. Al-Anber

1997-01-01

35

Analysis of Vapor-Liquid-Liquid Equilibrium in Coal Conversion Processes  

SciTech Connect

A new framework for analysis of vapor-liquid-liquid equilibrium has been developed. In this framework, the pure liquid fugacity is defined as the reference fugacity for all solvent species, and Henry's constant is defined as the reference fugacity for all solute species. This applies to vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibrium as well. A data reduction scheme that generates a consistent set of Henry's constant and activity coefficient parameters from isothermal and nonisothermal binary vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibrium data has been developed. The results of data reduction for several sets of vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibrium data are presented.

Sampath, V.R.; Leipziger, S.

1985-04-01

36

Measurement of vapor–liquid equilibrium for binary mixtures of phenol–dimethyl carbonate and phenol–methanol at 101.3 kPa  

Microsoft Academic Search

The isobaric vapor–liquid equilibrium (VLE) data for phenol–dimethyl carbonate (DMC) and phenol–methanol binary systems were measured at 101.3kPa by using a modified Rose–Williams still. The experimental VLE data have been tested for thermodynamic consistency via Herington analysis and correlated with Wilson, NRTL and UNIQUAC equations.

Wang-Ming Hu; Lv-Ming Shen; Lu-Jun Zhao

2004-01-01

37

Bilevel optimization formulation for parameter estimation in vapor–liquid(–liquid) phase equilibrium problems  

Microsoft Academic Search

A rigorous method is proposed for parameter estimation in thermodynamic models used for predicting vapor–liquid and vapor–liquid–liquid equilibrium of binary mixtures. Typically, vapor–liquid(–liquid) equilibria are modeled using asymmetric models, i.e., an excess Gibbs free energy model for the liquid phase and an equation of state for the vapor phase. Parameter estimation for asymmetric models is a nontrivial task. The existence

George M. Bollas; Paul I. Barton; Alexander Mitsos

2009-01-01

38

Vapor-liquid equilibrium of aromatic oil from coal hydrogasification  

SciTech Connect

The need for appropriate phase equilibrium data in the design of emerging coal conversion technology and particularly for the coal hydrogasification process has been the primary reason for the initiation of this project. A recirculation type vapor-liquid equilibrium (VLE) apparatus has been constructed for obtaining phase equilibrium data for complex hydrocarbon mixtures at high pressures and temperatures. A specially designed value has been used for obtaining equilibrium phase samples. The performance of the apparatus was tested for attainment of equilibrium in comparison with published data on VLE and N/sub 2/-n-decane systems. A systematic and complete VLE data for Ch/sub 4/-aromatic oil and H/sub 2/-aromatic oil systems, for pressures in the range of 20 to 110 atm and temperatures in the range of 400 to 550 K is presented. The multicomponent aromatic oil is a simulated light oil from coal hydrogasification without the presence of any highly polar components. Correlations for the estimation of hypothetical liquid phase pure component fugacities of hydrogen and methane, based on binary hydrocarbon VLE data, are presented. The correlations are to be used in conjunction with (1) the Prausnitz-Chueh modification of the Redlich-Kwong equation state for estimation of the vapor phase fugacity coefficients; (2) a slightly modified regular solution theory for estimation of activity coefficients and (3) the Lee-Edmister correlation for estimation of pure component hydrocarbon liquid phase fugacities at subcritical conditions. The methodology presented here has been tested for the computation of the VLE of a few ternary and quaternary systems at high pressures and temperatures with fair success. The technique presented here offers a viable means of estimation of high pressure and temperature VLE of complex hydrocarbon systems.

Srinivasan, R.

1981-01-01

39

Vapor-liquid equilibrium, coexistence curve, and critical locus for difluoromethane + pentafluoroethane (R-32 + R-125)  

Microsoft Academic Search

The vapor-liquid equilibrium for difluoromethane + pentafluoroethane (R-32 + R-125) was measured by the static method in the temperature range between 283 K and 313 K. The vapor-liquid coexistence curve near the critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of a 30 mass % R-32 and a 60 mass %

Yukihiro Higashi; Yukihiro

1997-01-01

40

Correlation of vapor-liquid equilibrium ratio of hydrogen  

SciTech Connect

In this work the correlation of vapor-liquid equilibrium ratio of hydrogen in the Chao-Seader correlation is updated with the use of new experimental data that have appeared in the intervening years. The correlation is extended in the direction of high temperature where much new data have been reported over a wide pressure range. The hydrogen correlation in the Chao-Seader correlation was based on experimental data in the temperature range of approximately 200--530 K that was the full extent of available data at the time. Grayson and Streed (1963) extended the hydrogen correlation to higher temperature using proprietary data on oil fractions. Since then a great deal of experimental investigation has been performed to determine the solubility of hydrogen at temperatures up to 730 K and pressure up to 25 MPa. Sebastian and coworkers (1981) developed a correlation for the solubility of hydrogen based on the expanded database. In this work the authors develop a new equation for the standard state liquid fugacity of hydrogen based on the expanded current database. The new equation will be useful to replace the equation for v of hydrogen in the Chao-Seader correlation that is found in process design software packages.

Jin, Z.L.; Greenkorn, R.A.; Chao, K.C. [Purdue Univ., West Lafayette, IN (United States). School of Chemical Engineering

1995-06-01

41

Vapor–liquid equilibrium in amino acid salt system: Experiments and modeling  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) measurements were carried out for both unloaded and CO2 loaded aqueous amino acid salt (AAS) solutions of the potassium salt of sarcosine (KSAR). Vapor–liquid equilibrium for unloaded solutions; 1.0–5.0M KSAR was measured using a Swietoslawski ebulliometer for temperatures 40, 60, 80 and 100°C and for total pressures 4.08–97.8kPa while vapor–liquid equilibrium for CO2 loaded solutions of 3.5M

Ugochukwu E. Aronu; Erik T. Hessen; Tore Haug-Warberg; Karl A. Hoff; Hallvard F. Svendsen

2011-01-01

42

Isobaric vapor-liquid equilibria of the water + 1-propanol system at 30, 60, and 100 kPa  

Microsoft Academic Search

Isobaric vapor-liquid equilibria for the water + 1-propanol system are reported at 30, 60, and 100 kPa. The results were found to be thermodynamically consistent according to Van Ness-Byer-Gibbs, Kojima, and Wisniak methods. The system shows a minimum boiling azeotrope, and the azeotropic composition is scarcely shifted with pressure. Results were compared with literature values. The data were correlated with

C. Gabaldon; P. Marzal; J. B. Monton; M. A. Rodrigo

1996-01-01

43

Activity Coefficient Models to Describe Vapor-Liquid Equilibrium in Ternary Hydro-Alcoholic Solutions  

Microsoft Academic Search

In this study, three semipredictive activity coefficient models: Wilson, non-random-two liquid model (NRTL), and universal quasi-chemical model (UNIQUAC), have been used for modeling vapor-liquid equilibrium properties of ternary mixtures that include substances found in alcoholic distillation processes of wine and musts. In particular, vapor-liquid equilibrium in ternary mixtures containing water + ethanol + congener has been modeled using parameters obtained

Claudio A. Faúndez; José O. Valderrama

2009-01-01

44

Vapor-liquid equilibrium measurements at 101. 32 kPa for binary mixtures of methyl acetate + ethanol or 1-propanol  

Microsoft Academic Search

This paper reports on isobaric vapor-liquid equilibrium data at 101.32 {plus minus} 0.02 kPa for methyl acetate (1) + ethane (2) or + 1-propanol (2). The results are compared with those predicted by the UNIFAC and ASOG methods. The methyl acetate (1) + ethanol (2) system forms an azeotrope at 329.8 K and a molar concentration of x⁠= 0.958.

Juan Ortega; Pedro Susial; Casiano De Alfonso

1990-01-01

45

Vapor-liquid equilibrium in electric field gradients.  

PubMed

We investigate the vapor-liquid coexistence of polar and nonpolar fluids in the presence of a nonuniform electric field. We find that a large enough electric field can nucleate a gas bubble from the liquid phase or a liquid droplet from the vapor phase. The surface tension of the vapor-liquid interface is determined within squared-gradient theory. When the surface potential (charge) is controlled, the surface tension increases (decreases) compared to the zero-field interface. The effect of the electric field on the fluid phase diagram depends strongly on the constitutive relation for the dielectric constant. Finally, we show that gas bubbles can be nucleated far from the bounding surfaces. PMID:21142049

Samin, Sela; Tsori, Yoav

2010-12-10

46

Vapor–liquid equilibrium measurements and correlations for an azeotropic system of ethane + hexafluoroethane  

Microsoft Academic Search

The research on the isothermal vapor–liquid phase behavior for the ethane (R170)+hexafluoroethane (R116) system is presented in this paper. The vapor–liquid equilibrium (VLE) data were measured at four temperatures 189.31, 192.63, 247.63 and 252.80K with an apparatus based on recirculation method. The experimental results were correlated with the Peng–Robinson equation of state using two types of mixing rules, the Panagiotopoulos–Reid

Yu Zhang; Mao-Qiong Gong; Hong-Bo Zhu; Jian-Feng Wu

2006-01-01

47

Vapor–liquid equilibrium in aqueous amine amino acid salt solution: 3-(methylamino)propylamine\\/sarcosine  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) measurements were conducted for both unloaded and CO2 loaded aqueous amine amino acid salt (AAAS) solutions; 3-(methylamino)propylamine\\/sarcosine (SARMAPA). Vapor–liquid equilibrium for unloaded solutions for 1.0–5.0M SARMAPA were measured using a Swietoslawski ebulliometer for temperatures 40–100°C and for total pressures 4.08–99.1kPa. CO2 equilibrium was determined for loaded 5M SARMAPA using low and high temperature VLE apparatuses from 40

Ugochukwu E. Aronu; Karl A. Hoff; Hallvard F. Svendsen

2011-01-01

48

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor–Liquid Equilibrium  

Microsoft Academic Search

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor–liquid equilibrium\\u000a for acid aqueous solutions and acid mixtures. The vapor–liquid equilibrium of hydrofluoric acid + salt systems (fluorite,\\u000a potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed\\u000a a salting-out effect on the vapor–liquid equilibrium of

Hideki Yamamoto; Iwao Sumoge

2011-01-01

49

Isobaric vapor-liquid equilibria of tetrachloroethylene + 1-propanol and + 2-propanol at 20 and 100 kPa  

SciTech Connect

Isobaric vapor-liquid equilibria were obtained for tetrachloroethylene + 1-propanol and +2-propanol systems at 20 and 100 kPa using a dynamic still. The experimental error in temperature was {+-} 0.1 K, in pressure {+-} 0.01 kPa and {+-} 0.1 kPa for the experiments carried out at 20 and 100 kPa, respectively, and in liquid and vapor composition 0.001. The two systems satisfy the point-to-point thermodynamic consistency test. Both systems show a positive deviation from ideality. The data were well correlated with the Wilson equation.

Dejoz, A.; Gonzalez-Alfaro, V.; Miguel, P.J.; Vazquez, M.I. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1996-11-01

50

Vapor-Liquid Equilibrium Measurements for Design of Coal Gasification Plants.  

National Technical Information Service (NTIS)

Results are reported on vapor-liquid equilibrium compositions of two synthetic mixtures - H sub 2 +CO+CO sub 2 +CH sub 4 +C sub 2 H sub 6 +Benzene and H sub 2 +CO+CH sub 4 +C sub 2 H sub 6 +C sub 2 H sub 4 +CO sub 2 +H sub 2 S+COS+Benzene. The equilibrium...

A. H. Hill G. L. Anderson

1984-01-01

51

Effect of magnesium chloride on the isobaric vapor–liquid equilibria of formic acid–water system  

Microsoft Academic Search

Formic acid and water form a maximum-boiling azeotrope in their mixtures. To break the azeotropic boiling in this system, inorganic salts are frequently added, because the addition of electrolytes alters significantly the equilibrium nature of the original system. In this paper we report the vapor–liquid equilibrium data for the formic acid–water–magnesium chloride system over a wide range of salt concentrations

Sei-Hun Yun; Chul Kim; Euy Soo Lee; Yeong-Cheol Kim

1998-01-01

52

Vapor–liquid equilibrium of systems containing alcohols, water, carbon dioxide and hydrocarbons using SAFT  

Microsoft Academic Search

The statistical associating fluid theory (SAFT) equation of state is employed for the correlation and prediction of vapor–liquid equilibrium (VLE) of eighteen binary mixtures. These include water with methane, ethane, propane, butane, propylene, carbon dioxide, methanol, ethanol and ethylene glycol (EG), ethanol with ethane, propane, butane and propylene, methanol with methane, ethane and carbon dioxide and finally EG with methane

Xiao-Sen Li; Peter Englezos

2004-01-01

53

Prediction of vapor–liquid equilibrium data for ternary systems using artificial neural networks  

Microsoft Academic Search

Most solvents used in the semiconductor industry are toxic and costly. Thus, the solvents should be recovered for re-use in these processes by distillation methods, and vapor–liquid equilibrium data are necessary for the design and operation of distillation columns. These data can be estimated using activity coefficient models. In this work, artificial neural networks were applied to predict and estimate

Viet D. Nguyen; Raymond R. Tan; Yolanda Brondial; Tetsuo Fuchino

2007-01-01

54

Thermodynamics in the treatment of vapor\\/liquid equilibrium (VLE) data  

Microsoft Academic Search

The Rossini lecture affords the lecturer an opportunity to review his contributions to a subject and to reflect on them from the perspective of an extended career. The subject here is vapor\\/liquid equilibrium, and the topics re- viewed include property relations, experimental measurements, consistency tests, and data reduction and correlation.

Hendrick C. Van Ness

1995-01-01

55

Prediction of vapor–liquid equilibrium for binary systems containing HFEs by using artificial neural network  

Microsoft Academic Search

A method using artificial neural network (ANN) was applied to estimate the vapor–liquid equilibrium (VLE) for the binary systems containing hydrofluoroethers (HFEs) and polar compounds. Our new estimation method is composed of three steps. In the first step, the sign of logarithm of activity coefficient (?) is estimated for each binary system using ANN, because it had been found that

Shingo Urata; Akira Takada; Junji Murata; Toshihiko Hiaki; Akira Sekiya

2002-01-01

56

A cubic equation of state for vapor-liquid equilibrium calculations of nonpolar and polar fluids  

Microsoft Academic Search

A cubic perturbed hard body (CPHB) equation of state (EOS) was developed and applied for vapor-liquid equilibrium (VLE) calculations in this study. The repulsive part of this EOS was investigated in our previous work. It is a simplified expression of hard body equation which yielded satisfactory agreement to the molecular simulation data of hard molecules from a single sphere to

Huei-Tung Wang; Jung-Chin Tsai; Yan-Ping Chen

1997-01-01

57

Vapor–Liquid Equilibrium of Ethanol–Water System in the Presence of Molecular Sieves  

Microsoft Academic Search

Adsorptive distillation is a new process to separate liquid mixtures in a packed distillation column. It depends on using active packing material instead of inert packing material in a packed distillation column. The active packing material can affect the intermolecular forces among the system components and thus alter its vapor–liquid equilibrium (VLE). The VLE of the ethanol–water system at 1

FAHMI A. ABU AL-RUB; FAWZI A. BANAT; RAMI JUMAH

1999-01-01

58

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

59

Computer simulation of vapor-liquid equilibrium in mixed solvent electrolyte solutions  

Microsoft Academic Search

We review Gibbs ensemble Monte Carlo sjmulations of vapor-liquid equilibrium in pure water, water\\/NaCl, water\\/methanol and water\\/methanol\\/Na~l mixtures. The intermolecular potentials used were taken directly from the published literature. The Ewald sum method with tinfoil boundary conditions was used to take into account long range forces.

HENRY J. STRAUCH; PETER T. CUMMINGS

1993-01-01

60

Recommended Vapor–Liquid Equilibrium Data. Part 4. Binary Alkanol–Alkene\\/Alkyne Systems  

Microsoft Academic Search

The recommended vapor–liquid equilibrium (VLE) data for binary mixtures of alkanols with alkenes and alkynes have been selected after critical evaluation of all data reported in the open literature up to the end of 2003. The evaluation procedure consisted in combining the thermodynamic consistency tests, data correlation, comparison with enthalpy of mixing data, and comparison of VLE data for various

Marian Go´ral; Andrzej Bok

2006-01-01

61

Thermodynamic Data to Support High-Temperature Syngas Quench Design: Vapor-Liquid Equilibrium Calculations.  

National Technical Information Service (NTIS)

A procedure has been developed, based on a dilute-solution model of the liquid phase and the rigorous viral expansion for the vapor phase, for modeling the vapor-liquid equilibrium between water and a synthetic gas consisting primary of H2, CO, and CO2. C...

A. H. Harvey

2008-01-01

62

New correlation of vapor-liquid equilibrium ratios internally consistent with critical behavior  

SciTech Connect

(1) Equilibrium ratios (K.Y/X) for calculating vapor-liquid equilibrium states have been correlated as functions of pressure, temperature, and convergence pressure for the normal paraffin hydrocarbons from methane through decane, isobutane, isopentane, nitrogen, and carbon dioxide. A model is proposed which relates the derivatives of the K-functions at convergence to the isothermal critical comositional locus of the system and is found to give very reasonable results for binary and ternary systems and two multicomponent mixures. A vapor-liquid phase-equilibrium algorithm incorporating this locus into the convergence pressure calculation was used to compute equilibrium phase compositions for comparison with expermental data from selected binary, ternary and multicomponent systems. 39 refs.

Lawal, A.S.; Silberberg, I.H.

1981-01-01

63

Vapor-liquid equilibrium measurements for dilute nitric acid solutions  

NASA Astrophysics Data System (ADS)

Equilibrium partial pressures of H 2O and HNO 3 were measured for dilute HNO 3 solutions between 0.3 and 6.8 m at 25°C. The new measurements extend the literature HNO 3 partial pressure data by two orders of magnitude down to 2 × 10 -8 a'tm. A critical evaluation of all data leads to a liquid-vapor equilibrium constant of 3.76 × 10 -7 for the HNO 3-H 2O system. This equilibrium constant, in conjunction with a complete set of activity coefficients also derived in this work, may be used to predict the equilibrium HNO 3 partial pressures at any HNO 3 concentrations. The results of a temperature study between 15 and 35°C are also reported.

Tang, I. N.; Munkelwitz, H. R.; Lee, J. H.

64

Aqueous Solutions of Polyelectrolytes: Vapor–Liquid Equilibrium and Some Related Properties  

Microsoft Academic Search

\\u000a This chapter reviews the thermodynamic properties of aqueous solutions of polyelectrolytes, concentrating on properties that\\u000a are related to phase equilibrium phenomena. The most essential phenomena as well as methods to describe such phenomena are\\u000a discussed from an applied thermodynamics point of view. Therefore, the experimental findings concentrate on the vapor–liquid\\u000a phase equilibrium phenomena, and the thermodynamic models are restricted to

G. Maurer; S. Lammertz; L. Schäfer

2011-01-01

65

Gibbs Ensemble Simulations of Vapor\\/Liquid Equilibrium Using the Flexible RWK2 Water Potential  

Microsoft Academic Search

Gibbs ensemble Monte Carlo simulations of water vapor\\/liquid equilibrium (VLE) using the flexible fixed charge RWK2 water-water potential are reported. The equilibrium densities, saturation pressures, and critical parameters calculated with this potential are in better agreement with experimental data than are values obtained from the SPC, MSPC\\/E, TIP4P, and TIP5P rigid fixed charge potentials as well as from polarizable interactions,

Zhenhao Duan; Nancy MOller; John H. Weare

2004-01-01

66

Acid Gas - Diethanolamine Vapor - Liquid Equilibrium Data by Fourier Transform Infrared Spectroscopy  

Microsoft Academic Search

A new apparatus for establishing vapor-liquid equilibrium (VLE) and a new method for measuring VLE data on acid gas - diethanolamine (DEA) systems are described. The acid gases studied were carbon dioxide (CO_2 ) and hydrogen sulfide (H_2S). The capability of the apparatus to establish an equilibrium was verified by reproducing data for CO_ {2}-water and H_2S -water systems. The

Richard Eugene Frazier

1993-01-01

67

Modeling vapor-liquid equilibrium of UFâ and common impurities  

Microsoft Academic Search

In the safe handling and processing of uranium hexafluoride (UFâ), it is often desirable to calculate vapor composition and pressure from known liquid composition and temperature. Furthermore, it would be economically advantageous to the International Atomic Energy Agency (IAEA), in its international safeguards program, and to uranium enrichment operators to be able to use analyses of equilibrium vapor-phase samples to

W. Jr. Davis; H. D. Cochran

1989-01-01

68

Effects of Ultrasonic Waves on Vapor-Liquid Equilibrium of an Azeotropic Mixture  

Microsoft Academic Search

Azeotropic and extractive distillation techniques used to separate azeotropic mixtures are among the most challenging separation processes in the chemical industry. In this work, an innovative distillation technique which employed ultrasonic waves was proposed to intensify the conventional multi-column azeotropic distillation method into a single-column alternative. The effects of ultrasonic intensity on the vapor-liquid equilibrium (VLE) of methyl-tert-butyl-ether (MTBE)-methanol was

Adnan Ripin; Siti Kholijah Abdul Mudalip; Zairina Sukaimi; Rosli Mohd Yunus; Zainuddin Abdul Manan

2009-01-01

69

Recommended Vapor–Liquid Equilibrium Data. Part 2: Binary Alkanol–Alkane Systems  

Microsoft Academic Search

The recommended vapor–liquid equilibrium (VLE) data for 36 binary systems involving primary, secondary, and tertiary alcohols with n-alkanes and isoalkanes [with the exception of 1-alkanols–n-alkane systems, which were presented in Part 1 of this series—J. Phys. Chem. Ref. Data 31(3), 702 (2002)] have been obtained after critical evaluation of all data (744 data sets) reported in the open literature up

Marian Go´ral; Adam Skrzecz; Andrzej Bok

2003-01-01

70

VAPOR-LIQUID EQUILIBRIUM DATA OF CHLOROFORM-ETHANOL MIXTURES INSIDE POLAR AND NONPOLAR POROUS PLATES  

Microsoft Academic Search

Vapor-liquid equilibrium (VLE) data of chloroform-ethanol mixtures at different temperatures were experimentally measured in 3 different macroporous plates: a 13.5-?m pore diameter, sintered, stainless-steel plate; a 30-?m pore diameter, porous, carbon plate; and a 30-?m pore diameter, porous, Teflon plate. The experimental results showed that the VLE of this system in the stainless steel plate was dramatically altered and the

Fahmi A. Abu Al-Rub; Hussein Allaboun; Ravindra Datta

2001-01-01

71

Calculation of vapor-liquid equilibrium availability function for multicomponent mixtures  

Microsoft Academic Search

A compulalional method of an availability function, which is essential to thermodynamic efficiency analysis of separation\\u000a processes, is provided. The proposed subroutines of vapor-liquid equilibrium entropy and subsequent availability function\\u000a are incorporated to the general thermodynamic properties estimation databanks of Fredenslund el al. [1] and Prausnilz el al.\\u000a [2]. The improved databank can be used to calculate availability function of

Ki Deog Choi; Hyung-Sang Park; Ki-Pung Yoo

1988-01-01

72

Activity coefficient models to describe isothermal vapor-liquid equilibrium of binary systems containing ionic liquids  

Microsoft Academic Search

Isothermal vapor-liquid equilibrium data of binary mixtures containing ionic liquids are correlated using three activity coefficient\\u000a models: UNIQUAC, Wilson, and NRTL. Twenty binary systems taken from the literature were selected for this study. A genetic\\u000a algorithm is used to determine the interaction parameters for the three models. The results given by the three models have\\u000a been compared with experimental data,

J. A. Lazzús; J. Marín

2010-01-01

73

Thermodynamic modeling of the vapor–liquid equilibrium of the water\\/ethanol\\/CO 2 system  

Microsoft Academic Search

The Cubic Plus Association Equation of State (CPA EoS) developed in this laboratory is applied here in the correlation of the binary vapor–liquid equilibrium (VLE) and in the prediction of the ternary VLE of the water\\/ethanol\\/carbon dioxide system at various temperatures and pressures. Carbon dioxide is treated in three different ways: (a) as a non-associating molecule, (b) as an only

Christophoros Perakis; Epaminondas Voutsas; Kostis Magoulas; Dimitrios Tassios

2006-01-01

74

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

75

Vapor–liquid equilibrium simulations of the SCPDP model of water  

Microsoft Academic Search

Molecular simulations were carried out using the self-consistent point dipole polarizability model (SCPDP) of water in the region of vapor–liquid equilibrium. The methods of isothermal–isochoric molecular dynamics (NVT–MD) and Gibbs ensemble Monte Carlo (GEMC) were employed to calculate orthobaric densities and vapor pressures; NVT–MD also yields surface tensions and interface thickness. Agreement was found between the two methods, particularly at

J. L. Rivera; M. Predota; A. A. Chialvo; P. T. Cummings

2002-01-01

76

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

77

Vapor-liquid equilibrium of near-critical binary alkane mixtures  

Microsoft Academic Search

The modified Leung-Griffiths model of Rainwater and Moldover is used to correlate vapor-liquid equilibrium (VLE) surfaces in pressure, temperature, and density for binary mixtures in the near-critical region. The systems studied are butane-pentane, propane-isopentane, butane-hexane, and ethane-butane. The model, which has also successfully fit several other mixtures, is based on scaling-law equations of state expressed in terms of field variables.

J. C. Rainwater; F. R. Williamson; H. J. M. Hauley; A. Cezairliyan

1986-01-01

78

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 Faúndez; Felipe Andrés Urbina; José Omar Valderrama

2009-01-01

79

Vapor-liquid equilibrium in binary and ternary mixtures of nitrogen, argon, and methane  

Microsoft Academic Search

Vapor-liquid equilibrium (VLE) values are required in technological applications and are fundamental to separation operations. In this work the authors report VLE data on the three binary mixtures and the ternary system of nitrogen, argon, and methane at 122.89 K. The experimental VLE values on the binary mixtures were correlated with the Peng-Robinson equation of state, and used to predict

Zhangli Jin; Kunyuan Liu; Wangwang Sheng

1993-01-01

80

An Assessment of Thermodynamic Consistency Tests for Vapor-Liquid Equilibrium Data  

Microsoft Academic Search

Consistency tests are techniques that allow, in principle, the assessment of experimental vapor-liquid equilibrium data on the basis of the Gibbs-Duhem equation. Much empiricism and arbitrariness is frequently observed in the analysis and application of consistency tests, a situation that may question their usefulness. Perfect data satisfy exactly the Gibbs-Duhem relation, but acceptable data obey it within a tolerable limits

Jaime Wisniak; Alexander Apelblat; Hugo Segura

1997-01-01

81

Theoretical study of vapor–liquid equilibrium inside capillary porous plates  

Microsoft Academic Search

A generalized thermodynamic framework is provided for vapor–liquid equilibrium (VLE) in the presence of external fields and is utilized to develop a semi-empirical model for VLE within porous materials that accounts for the effect of the long-range surface forces. The alteration of VLE of binary mixtures in capillary porous plates is explained on the basis of the effect of long-range

Fahmi A. Abu Al-Rub; Ravindra Datta

1999-01-01

82

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 COâ + methanol at 313.05 K, COâ + 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

83

Vapor-liquid equilibrium in the ternary system hexane + 1-chlorobutane + 2-propanol and its binaries  

Microsoft Academic Search

Vapor-liquid equilibrium at 94.4 kPa has been determined for the ternary system hexane + 1-chlorobutane + 2-propanol and the binary systems hexane + 1-chlorobutane and 1-chlorobutane + 2-propanol. The binary system hexane + 1-chlorobutane exhibits moderate deviations from ideality and an azeotrope that contains 97.5 mol % hexane and boils at 339.25 K. The binary system 1-chlorobutane + 2-propanol presents

J. Wisniak; A. Akunis

1995-01-01

84

Solvent-refined coal (SRC) process. Vapor-liquid equilibrium measurements for the SRC-II process  

Microsoft Academic Search

This report summarizes vapor-liquid equilibrium studies conducted to support the Solvent Refined Coal project by the Pittsburg and Midway Coal Mining Company under contract with the Department of Energy. Discussed herein are experimental details and results of measurements to obtain vapor-liquid equilibrium data at conditions simulating those which occur during the gas-liquid separation steps in the SRC-II coal liquefaction process.

1980-01-01

85

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

Microsoft Academic Search

Conclusions  The 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 Raoult’s 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 Raoult’s law at a pressure of 4.00.2 mm.

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

1946-01-01

86

Vapor-liquid equilibrium in the system methyl ethyl ketone-p-xylene  

SciTech Connect

New vapor-liquid equilibrium data have been obtained for the binary system methyl ethyl ketone-p -xylene at 760 mmHg to compare with previously reported data assumed to be thermodynamically inconsistent. The system presents slight positive deviations from ideal solution behavior. The activity coefficients are well correlated by a three-constant Redlich-Klster equation and by the Wilson equation. Boiling points are adequately described by a four-constant equation, and vapor composition is very accurately predicted by the UNIFAC method.

Wisniak, J.; Tamir, A.

1982-10-01

87

Vapor-liquid equilibrium in binary and ternary mixtures of nitrogen, argon, and methane  

SciTech Connect

Vapor-liquid equilibrium (VLE) values are required in technological applications and are fundamental to separation operations. In this work the authors report VLE data on the three binary mixtures and the ternary system of nitrogen, argon, and methane at 122.89 K. The experimental VLE values on the binary mixtures were correlated with the Peng-Robinson equation of state, and used to predict the VLE values for the binary system. The predicted values were than compared with the experimental results. Calculated pressure and vapor composition from the equation are compared with the ternary mixture data. The experimental results are successfully correlated with the Peng-Robinson equation of state.

Zhangli Jin; Kunyuan Liu; Wangwang Sheng (Beijing Inst. of Chemical Technology (China). Dept. of Chemical Engineering)

1993-07-01

88

Testing the recent charge-on-spring type polarizable water models. II. Vapor-liquid equilibrium  

NASA Astrophysics Data System (ADS)

We studied the vapor-liquid coexistence region of seven molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS/G2, COS/G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004)], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003)], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006)], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012)] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011)], while the BKd3 model has variable size to approximate the temperature-density (T-?) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 194102 (2012)]. We calculated the second virial coefficient, the heat of vaporization, equilibrium vapor pressure, the vapor-liquid coexistence curve, and the surface tension in terms of the temperature. We determined and compared the critical temperatures, densities, and pressures of the models. We concluded that the high temperature slope of the (T-?) curve accurately predicts the critical temperature. We found that Gaussian charge distributions have clear advantages over the point charges describing the critical region. It is impossible to describe the vapor-liquid coexistence properties consistently with nonpolarizable models, even if their critical temperature is correct.

Kiss, Péter T.; Baranyai, András

2012-11-01

89

Testing the recent charge-on-spring type polarizable water models. II. Vapor-liquid equilibrium.  

PubMed

We studied the vapor-liquid coexistence region of seven molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS?G2, COS?G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004)], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003)], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006)], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012)] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011)], while the BKd3 model has variable size to approximate the temperature-density (T-?) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 194102 (2012)]. We calculated the second virial coefficient, the heat of vaporization, equilibrium vapor pressure, the vapor-liquid coexistence curve, and the surface tension in terms of the temperature. We determined and compared the critical temperatures, densities, and pressures of the models. We concluded that the high temperature slope of the (T-?) curve accurately predicts the critical temperature. We found that Gaussian charge distributions have clear advantages over the point charges describing the critical region. It is impossible to describe the vapor-liquid coexistence properties consistently with nonpolarizable models, even if their critical temperature is correct. PMID:23181290

Kiss, Péter T; Baranyai, András

2012-11-21

90

Correlation of Vapor–Liquid Equilibrium for Carbon Dioxide + Ethanol + Water at Temperatures from 35 to 70°C  

Microsoft Academic Search

A simple mathematical model, based on polynomial functions, was used to correlate experimental vapor–liquid equilibrium (VLE) data for the CO2 + ethanol + water system. The data were collected from the literature for temperatures 35, 40, 50, 60, and 70°C and pressures from 10 MPa to 18.5 MPa. This model is able to reproduce the equilibrium compositions of the two

CATARINA DUARTE; ANA AGUIAR-RICARDO; NUNO RIBEIRO; TERESA CASIMIRO; MANUEL NUNES DA PONTE

2000-01-01

91

Isothermal vapor-liquid equilibrium accompanied by esterification; ethanol-formic acid system  

SciTech Connect

The equilibrium total pressures after reaction between ethanol and formic acid were measured at 30, 40 and 50/sup 0/C, and the compositions of the vapor and liquid phases were determined gas chromatographically. Since the presence of the carboxylic acid in the mixture induces dimerization and trimerization of the acid in the vapor phase, the modified fugacity coefficients were calculated from ''chemical'' theory using the Lewis fugacity rule, from which are calculated the activity coefficients and the vapor-phase mole fractions using the nonrandom, two-liquid (NRTL) equation. The parameters in the NRTL equation were obtained from vapor-liquid equilibrium data for the binary system. The calculated results agree closely with the experimental vapor-phase mole-fraction data.

Rim, J.K.; Bae, S.Y.; Lee, H.T.

1985-07-01

92

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

93

Vapor-liquid equilibrium of ethanol-water system in the presence of molecular sieves  

SciTech Connect

Adsorptive distillation is a new process to separate liquid mixtures in a packed distillation column. It depends on using active packing material instead of inert packing material in a packed distillation column. The active packing material can affect the intermolecular forces among the system components and thus alter its vapor-liquid equilibrium (VLE). The VLE of the ethanol-water system at 1 atm was studied using a circulation still in the absence and in the presence of different amounts of 4 {angstrom} molecular sieves. The results obtained showed that the VLE of the system was altered in the presence of the molecular sieves, the azeotropic point of the system (at 89.7 mol% ethanol in the normal case) was eliminated and considerable separation was achieved for a mixture of azeotropic composition, and the alteration in the VLE of a given binary mixture is a function of the pore size and the amount of the molecular sieves.

Abu Al-Rub, F.A.; Banat, F.A.; Jumah, R. [Jordan Univ. of Science and Technology, Irbid (Jordan). Dept. of Chemical Engineering

1999-09-01

94

Modeling vapor-liquid equilibrium of UF/sub 6/ and common impurities  

SciTech Connect

In the safe handling and processing of uranium hexafluoride (UF/sub 6/), it is often desirable to calculate vapor composition and pressure from known liquid composition and temperature. Furthermore, it would be economically advantageous to the International Atomic Energy Agency (IAEA), in its international safeguards program, and to uranium enrichment operators to be able to use analyses of equilibrium vapor-phase samples to calculate liquid-phase compositions. Either type of calculation could be performed with a multicomponent vapor-liquid equilibrium (VLE) model if this model were shown to apply to UF/sub 6/ and its common impurities. In the present and earlier studies, the model and computer programs developed by J.M. Prausnitz and his coworkers has been adapted and tested for their ability to correlate experimental data on vapor-liquid equilibria between UF/sub 6/ and some of its many potential impurities. Because of its polymerization, hydrogen fluoride must be treated as a special component. However, VLE of the balance of components, including N/sub 2/, O/sub 2/, F/sub 2/, SiF/sub 4/, and ClF/sub 3/, are accurately described by treating vapor-phase nonidealities by the Haydon-O'Connell equation and liquid-phase nonidealities by the UNIQUAC equation in the model of Prausnitz et al. This report describes the results of analyzing VLE involving UF/sub 6/ as a solute for some known impurities. It also describes the formation of F/sub 2/ and lower uranium fluorides from the self ..cap alpha..-radiolytic decomposition of UF/sub 6/. 68 refs., 7 figs., 7 tabs.

Davis, W. Jr.; Cochran, H.D.

1989-03-01

95

Vapor-liquid equilibrium thermodynamics of N2 + CH4: Model and Titan applications  

NASA Astrophysics Data System (ADS)

Calculations of the vapor-liquid equilibrium thermodynamics of the N2 + CH4 system show that the tropospheric clouds of Titan are not pure CH4, but solutions of CH4 containing substantial quantities of N2. The conditions for saturation, latent heat of condensation, and droplet composition all depend on this equilibrium. We present a thermodynamic model for vapor-liquid equilibrium in the N2 + CH4 system which, by its structure, places strong constraints on the consistency of experimental equilibrium data, and confidently embodies temperature effects by also including enthalpy (heat of mixing) data. Selected equilibrium and enthalpy data are used in a maximum likehood determination of model parameters. The model can be readily evaluated to compute the saturation criteria, composition of condensate, and latent heat in Titan's atmosphere for a given pressure-temperature (p-T) profile. For a nominal p-T profile, the partial pressure of CH4 required for formation of CH4 + N2 condensate is ˜20% lower than that required to saturate pure CH4, and ˜25% higher than that which would be computed by Raoult's law. N2 constitutes 16-30% of the cloud condensate, and higher altitude clouds are generally more N2-rich. The N2 content of condensate is ˜1/2 of that computed from Raoult's law and about 30% greater than that computed from Henry's law. Heats of condensation are ˜10% lower than for pure CH4. Above 14 km altitude, the liquid solution becomes metastable with respect to a solid solution containing less N2: freezing of liquid droplets will be accompanied by the exsolution of about 30% of the dissolved N2, probably leading to an underdense, porous texture. The refractive index, single-scattering albedo, and density of CH4 + N2 cloud droplets of the appropriate composition and phase should be used in modeling and spacecraft planning studies for Titan. Cassini investigations with sufficient altitude resolution (primarily Huygens probe experiments) can potentially detect vertical motion of particles by determining whether condensate and gas are in local thermodynamic equilibrium.

Reid Thompson, W.; Zollweg, John A.; Gabis, David H.

1992-06-01

96

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium  

NASA Astrophysics Data System (ADS)

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

Yamamoto, Hideki; Sumoge, Iwao

2011-03-01

97

Novel bare-bones particle swarm optimization and its performance for modeling vapor–liquid equilibrium data  

Microsoft Academic Search

Parameter estimation in models plays a significant role in developing mathematical models which are used for understanding and analyzing physical, chemical and biological systems. Parameter estimation problems for vapor–liquid equilibrium (VLE) data modeling are very challenging due to the high non-linearity of thermodynamic models. Recently, stochastic global optimizations and their applications to these problems have attracted greater interest. Of the

Haibo Zhang; Devid Desfreed Kennedy; Gade Pandu Rangaiah; Adrián Bonilla-Petriciolet

2011-01-01

98

Generalized temperature-dependent parameters of the Redlich-Kwong equation of state for vapor-liquid equilibrium calculations  

Microsoft Academic Search

Equations of state are usually used for predicting vapor-liquid equilibrium and volumetric properties in the absence of experimental data. Among the equations of state frequently used in chemical engineering is that proposed by Redlich and Kwong in 1949. It is remarkably simple and can be employed in all property estimation systems. It has been the subject of much research in

Salah E. M. Hamam; W. K. Chung; I. M. Elshayal; Benjamin C.-Y. Lu

1977-01-01

99

Vapor-liquid equilibrium of a multipolar square-well fluid II. Effect of a variable square-well range  

Microsoft Academic Search

The multipolar square-well (MSW) fluid treated in part I [Physica A 202 (1994) 420] is studied in order to analyze the effect of SW range ?, which models the range of dispersion forces, on the vapor-liquid (VL) equilibrium. The model includes a simpler and more accurate treatment of the SW interactions of variable width. The MSW model covers systems ranging

Fernando del Río; Ana Laura Benavides; Yolanda Guevara

1995-01-01

100

Statistical analysis of data for three-component vapor-liquid equilibrium diagrams of various topological types  

Microsoft Academic Search

The topological types of vapor-liquid equilibrium diagrams and the numbers of different topological types have been determined\\u000a for 8071 three-component systems. The set of diagrams has been analyzed statistically in terms of diagram types, the numbers\\u000a and types of azeotropes, and the types of singular points.

S. A. Reshetov

2009-01-01

101

DETERMINATION OF INFINITE DILUTION ACTIVITY COEFFICIENTS FOR ORGANIC-AQUEOUS SYSTEMS USING A DILUTE VAPOR-LIQUID EQUILIBRIUM METHOD  

Microsoft Academic Search

A low pressure vapor-liquid equilibrium apparatus has been developed, tested and verified for the measurements of dilute solution activity coefficients for different organic solutes in aqueous systems. Activity coefficient data were measured for aqueous binary mixtures involving methanol, acetone, and benzene at 25°C. The experimental measurements targeted the range of solute liquid compositions extending from the Gas Chromalograph detection limit

M. S. H. BADER; K. A. M. GASEM

1995-01-01

102

Vapor-Liquid Equilibrium of the Mixture C2H6OS + C6H6 (LB3439, EVLM 1111)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A2 `Binary Liquid Systems of Nonelectrolytes, Part 2' of Volume 13 `Vapor-Liquid Equilibrium in Mixtures and Solutions' of Landolt-Börnstein Group IV `Physical Chemistry'. It corresponds to the entry LB3439 of the Print Version and the ELBT Database, respectively.

Wichterle, I.; Linek, J.; Wagner, Z.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

103

Vapor-liquid equilibrium measurements for design of coal gasification plants  

SciTech Connect

Results are reported on vapor-liquid equilibrium compositions of two synthetic mixtures - H/sub 2/+CO+CO/sub 2/+CH/sub 4/+C/sub 2/H/sub 6/+Benzene and H/sub 2/+CO+CH/sub 4/+C/sub 2/H/sub 6/+C/sub 2/H/sub 4/+CO/sub 2/+H/sub 2/S+COS+Benzene. The equilibrium conditions investigated range from 323 to 479 K and 2280 to 19720 kPa. Based on this study, the Peng-Robinson correlation appears to be slightly better than the Soave-Redlich-Kwong correlation in predicting the phase equilibrium behavior of these complex mixtures. Both correlations are superior to the Grayson-Streed and Chao-Seader correlations. However, the Peng-Robinson correlation still shows some areas where improvements can be made. Specifically, for this six-component system it was observed that - actual hydrogen, methane, and carbon monoxide solubility in the liquid phase is greater than that predicted by the Peng-Robinson correlation under all conditions, and actual benzene, carbon dioxide, and ethane solubility in the gas phase is greater than that predicted under all conditions. 19 references, 7 figures, 10 tables.

Hill, A.H.; Anderson, G.L.

1984-01-01

104

A simplified CEOS\\/ A E mixing rule and its applications for vapor–liquid and liquid–liquid equilibrium predictions  

Microsoft Academic Search

The new CEOS\\/AE mixing rule recently developed by Twu et al. [Fluid Phase Equilib. 158–160 (1999) 271] is simplified and tested for high-pressure vapor–liquid equilibrium (VLE) and liquid–liquid equilibrium (LLE) predictions. This mixing rule has some significant features such as: (1) it is density dependent, (2) it is based on no reference-pressure, and (3) it automatically reduces to van der

Ting-Horng Chung; Chorng H. Twu

2001-01-01

105

Simultaneous estimation of excess enthalpy, excess Gibbs energy and vapor-liquid equilibrium using the modified Wilson model  

Microsoft Academic Search

A modified Wilson equation proposed in our previous paper [1] successfully improved the correlation of ternary liquid-liquid equilibrium, especially for Type I partially miscible mixtures. In this paper we attempt to extend the application of this modified model to simultaneously correlate thermodynamic properties of excess enthalpy, hE, and excess Gibbs free energy, gE, and vapor-liquid equilibrium. We collected data for

Jin-Feng Huang; Liang-sun Lee

1996-01-01

106

Salt effect of LiCl on vapor–liquid equilibrium of the acetone–methanol system  

Microsoft Academic Search

The effect of lithium chloride (LiCl) at salt mole fractions from 0.005 to 0.15 and at saturation on vapor–liquid equilibrium (VLE) of the binary acetone–methanol system has been experimentally investigated at 101.32 kPa using a modified Othmer equilibrium still, in order to elucidate the behavior of this mixture whose existing data are rather contradictory. The salting-out effect of the salt

Maria C. Iliuta; Ion Iliuta; Ortansa M. Landauer; Fernand C. Thyrion

1998-01-01

107

Isobaric vapor-liquid equilibria for binary systems composed of octane, decane, and dodecane at 20 kPa  

SciTech Connect

The most common operation in the chemical industry is the separation of liquid mixtures through distillation. Efficient design of distillation equipment requires quantitative knowledge of vapor-liquid equilibria (VLE) in binary or multicomponent mixtures. Vapor-liquid equilibria were measured for binary systems of octane + decane, decane + dodecane, and octane + dodecane at 20.00 kPa using a recirculating still. The results are thermodynamically consistent according to the point-to-point consistency test, and deviation from ideal behavior is small for all systems.

Dejoz, A.; Gonzalez-Alfaro, V.; Miguel, P.J.; Vazquez, M.I. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1996-01-01

108

Simulation and Estimation of Vapor-Liquid Equilibrium for Asymmetric Binary Systems (CO 2 Alcohols) Using Artificial Neural Network  

Microsoft Academic Search

Since it is not always possible to carry out experiments at all desired temperatures and pressures, generally thermodynamic\\u000a models based on equations of state are used for estimation of vapor-liquid equilibrium. In this work, a method using artificial\\u000a neural network (ANN) was designed and applied to simulate and estimate the VLE for the binary asymmetric systems containing\\u000a CO2 and Alcohols.

Reza Abedini; Iman Zanganeh; Mohammad Mohagheghian

2011-01-01

109

A New Hard Sphere Cubic Equation of State for Predicting Fluids’ Properties and Vapor-Liquid Phase Equilibrium Calculations  

Microsoft Academic Search

In this study, a new cubic hard sphere equation of state (EOS) was developed from standard classical thermodynamics. The new\\u000a equation is applied to calculate properties of fluids and vapor-liquid phase equilibrium calculations. The derived equation\\u000a is a simplified expression of the hard sphere equation which yields satisfactory agreement with the molecular simulation of\\u000a hard molecule data. The EOS is

S. Hajipour; M. Edalat

2008-01-01

110

Vapor-liquid equilibrium, coexistence curve, and critical locus for binary HFC32\\/HFC134a mixture  

Microsoft Academic Search

Two kinds of equilibrium measurements of binary R-32\\/134a mixtures were carried out. The vapor-liquid equilibria were measured by the static method in the temperature range between 283 and 313 K. On the basis of the present experimental data, the temperature dependence of the binary interaction parameterk12 for two equations of state, namely, the Soave-Redlich-Kwong equation and Carnahan-Starling-De Santis equation, was

Y. Higashi

1995-01-01

111

Vapor–liquid equilibrium of carbon dioxide with ethyl caproate, ethyl caprylate and ethyl caprate at elevated pressures  

Microsoft Academic Search

Vapor–liquid 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 Soave–Redlich–Kwong and the Peng–Robinson equations of state with various

Weng-Hong Hwu; Jaw-Shin Cheng; Kong-Wei Cheng; Yan-Ping Chen

2004-01-01

112

Effect of dissolved inorganic salts on the isothermal vapor–liquid equilibrium of the propionic acid–water mixture  

Microsoft Academic Search

Propionic acid–water is one of the minimum boiling point azeotropic binary mixtures. Alteration of the vapor–liquid equilibrium (VLE) by addition of inorganic salts is of interest, since it allows bypassing the azeotropic point due to salt-in and salt-out effects. The effect of NaCl, NH4Cl, CaCl2, and AlCl3 at salt concentrations of 1 m and the effect of NaCl molality (0.5–3

Fawzi Banat; Sameer Al-Asheh; Jana Simandl

2002-01-01

113

Vapor-liquid equilibrium calculation of the system water-nitric acid over the entire concentration range  

Microsoft Academic Search

The vapor-liquid equilibrium of the system water-nitric acid has been described. The activity coefficients in the liquid phase are evaluated according to a new model. This model combines the effect of the long range forces expressed by a Debye-Hückel contribution on a mole fraction basis, with the effect of short range forces expressed by a virial expansion of the NRTL

Stefano Brandani; Vincenzo Brandani

1996-01-01

114

Deviations from corresponding-states behavior in the vapor-liquid equilibrium of the square-well fluid  

Microsoft Academic Search

The vapor-liquid equilibrium of the square-well (SW) fluid of variable range is studied. The analysis focuses on the dependence on the SW range, which exhibits deviations from corresponding-states behavior. The study is based on a new, compact and accurate equation for the SW Helmholtz free-energy. This equation relies on the mean-field approximation and a scaled-particle theory of Boublík, and agrees

Alejandro Gil-Villegas; Fernando del Río; Ana Laura Benavides

1996-01-01

115

Evaluation of vapor—liquid equilibrium of CO 2 binary systems using UNIQUAC-based Huron—Vidal mixing rules  

Microsoft Academic Search

Since Huron and Vidal [M.J. Huron, J. Vidal, Fluid Phase Equilib. 3 (1979) 255] developed the basic idea of the so-called GE mixing rules, similar models have been proposed by different authors. In most of them, a group-contribution method like the UNIFAC model is used with the equation of state to enable the description of vapor-liquid equilibrium (VLE) at high

A. Keshtkar; F. Jalali; M. Moshfeghian

1997-01-01

116

Vapor–Liquid-Equilibrium (VLE) properties of R-32+R-134a system derived from isochoric measurements  

Microsoft Academic Search

Two methods developed for deriving Vapor–Liquid-Equilibrium (VLE) data from isochoric measurements are presented in this paper. The first, so-called `flash' method depends on a knowledge of the volumetric properties, estimated by means of an appropriate model; in the present case, the Carnahan–Starling–De Santis (CSD) equation of state (EOS) was used to predict the mixture's behavior. As for the second, so-called

G. Di Nicola; G. Giuliani; G. Passerini; F. Polonara; R. Stryjek

1998-01-01

117

Analysis of vapor–liquid equilibrium of ethanol–water system via headspace gas chromatography: effect of molecular sieves  

Microsoft Academic Search

The effect of the presence of 3 and 4Å molecular sieves on the vapor–liquid equilibrium (VLE) of the ethanol–water system was investigated using the headspace gas chromatography (HSGC) technique. The VLE of the system was considerably altered in the presence of molecular sieves and the azeotropic point was eliminated. Attractively, in the presence of molecular sieves, pure ethanol was obtained

Fawzi A. Banat; Fahmi A. Abu Al-Rub; Jana Simandl

2000-01-01

118

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

119

Vapor-liquid equilibrium, coexistence curve, and critical locus for binary HFC-32/HFC-134a mixture  

NASA Astrophysics Data System (ADS)

Two kinds of equilibrium measurements of binary R-32/134a mixtures were carried out. The vapor-liquid equilibria were measured by the static method in the temperature range between 283 and 313 K. On the basis of the present experimental data, the temperature dependence of the binary interaction parameter k 12 for two equations of state, namely, the Soave-Redlich-Kwong equation and Carnahan-Starling-De Santis equation, was discussed. The vapor-liquid coexistence curve near the critical point was also measured by the observation of meniscus disappearance. The critical temperatures and critical densities of 30 and 70 wt% R-32 mixtures were determined on the basis of the saturation densities along the coexistence curve in the critical region. In addition, a correlation of the critical locus for this mixture is proposed as a function of composition.

Higashi, Y.

1995-09-01

120

Densities and isobaric vapor-liquid equilibria for the mixtures formed by four butyl esters and 1-butanol  

SciTech Connect

Densities of 298.15 K and the vapor-liquid equilibria for 1-butanol + butyl methanoate, + butyl ethanoate, + butyl propanoate, and + butyl butanoate have been measured at 101.32 kPa in small capacity ebulliometer. All results were found to be thermodynamically consistent with a point-to-point test. The mixtures containing butyl methanoate and butyl ethanoate show azeotropes at T = 379.14 K, x = 0.871 and T = 389.64 K, x = 0.222, respectively. Different group-contribution methods were applied to these mixtures.

Gonzalez, E.; Ortega, J. [Univ. of Las Palmas de Gran Canaria (Spain)

1996-01-01

121

Experimental researches on characteristics of vapor–liquid equilibrium of NH 3–H 2O–LiBr system  

Microsoft Academic Search

An improved system of NH3–H2O–LiBr was proposed for overcoming the drawback of NH3–H2O absorption refrigeration system. The LiBr was added to NH3–H2O system anticipating a decrease in the content of water in the NH3–H2O–LiBr system. An equilibrium cell was used to measure thermal property of the ternary NH3–H2O–LiBr mixtures. The pressure–temperature data for their vapor–liquid equilibrium (VLE) data were measured

Yuyuan Wu; Yan Chen; Tiehui Wu

2006-01-01

122

Vapor–liquid equilibrium in polymer–solvent systems with a cubic equation of state  

Microsoft Academic Search

A cubic equation of state (EoS), the Peng–Robinson (PR) one, is extended to polymers by using a single set of energy (a) and co-volume (b) parameters per polymer fitted to experimental volume data. Excellent results for the volumetric behavior of the polymer up to 2000 bar pressure are obtained. The EoS is applied to the correlation of low pressure vapor–liquid

Vassiliki Louli; Dimitrios Tassios

2000-01-01

123

ARTICLES: Vapor-Liquid Equilibrium Data of Carbon Dioxide+Methyl Propionate and Carbon Dioxide+Propyl Propionate Systems  

NASA Astrophysics Data System (ADS)

High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate+carbon dioxide and propyl propionate+carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry's coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

Xu, Wei; Xie, Chuan-xin; Li, Hong-ling; Tian, Yi-ling

2010-06-01

124

Vapor-Liquid Equilibrium Measurements and Modeling for Ternary System Water + Ethanol + 1Butyl3-methylimidazolium Acetate  

Microsoft Academic Search

Vapor-liquid equilibrium (VLE) data were measured for ternary system water + ethanol + 1-butyl-3-methylimidazolium acetate ([bmim][OAc]), in a relatively wide range of ionic liquid (IL) mass fractions up to 0.8. Six sets of complete T-x-y data were obtained, in which the mole fraction of ethanol on IL-free basis was fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and approximate 0.98.

Dongshun DENG; Rufa WANG; Lianzhong ZHANG; Yun GE; Jianbing JI

2011-01-01

125

Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane + 1,1,1-trifluoroethane (R125\\/R143a)  

Microsoft Academic Search

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1-trifluoroethane (R143a) was measured by the static method in the temperature range between 273.15 K and 313.15 K. The vapor-liquid coexistence curve near the critical point was measured by observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.4118 and 0.6208 mole fraction of R125 were determined from the

Yukihiro Higashi; Yukihiro

1999-01-01

126

Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane + 1,1,1,2-tetrafluoroethane (R125\\/R134a)  

Microsoft Academic Search

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1,2-tetrafluoroethane (R134a) was measured along four isotherms between 283 K and 313 K. The vapor-liquid coexistence curve at constant composition near the mixture critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.2670 and 0.6648 mole fraction of R125 were determined from the

Yukihiro Higashi; Yukihiro

1999-01-01

127

Solvent-refined coal (SRC) process. Vapor-liquid equilibrium measurements for the SRC-II process  

SciTech Connect

This report summarizes vapor-liquid equilibrium studies conducted to support the Solvent Refined Coal project by the Pittsburg and Midway Coal Mining Company under contract with the Department of Energy. Discussed herein are experimental details and results of measurements to obtain vapor-liquid equilibrium data at conditions simulating those which occur during the gas-liquid separation steps in the SRC-II coal liquefaction process. Separation and compositional analyses of liquid and gas phases permitted calculation of the equilibrium K values for the various components of the mixture. Experimental methods and apparatus used in this work were compared to a system recently described in the literature. The measured K values agreed to within an average of +- 5% of published values and showed that the experimental system developed is satisfactory. Internal consistency of each experiment was evaluated by a material balance consistency test, and an average material balance of 99.7% was obtained over the 15 experiments. Data obtained from this work will serve as the basis for K value correlations used in process design calculations for the SRC-II Demonstration Plant.

Henry, R.M.

1980-10-01

128

Vapor–liquid 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=335–463K. The experimental vapor pressures were fitted well with the Antoine equation. Isobaric vapor–liquid 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

129

Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. [Vapor-liquid equilibrium  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor--liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 [times] 10[sup 14] BTU/yr.

Bullin, J.A.; Frazier, R.E.

1992-01-01

130

Experimental Determination of Densities and Isobaric Vapor-Liquid Equilibria of Methyl Acetate and Ethyl Acetate with Alcohols (C3 and C4) at 0.3 MPa  

NASA Astrophysics Data System (ADS)

The densities and excess volumes were determined at 298.15 K for the methyl acetate + 1-propanol, methyl acetate + 1-butanol, and ethyl acetate + 1-butanol mixtures. The vapor-liquid equilibria data at 0.3 MPa for these binary systems were obtained using a stainless steel equilibrium still. The activity coefficients were obtained from the experimental data using the Hayden and O'Connell method and the Yen and Woods equation. The binary systems in this study showed positive deviations from ideality. The experimental VLE data were verified with the point-to-point test of van Ness using the Barker routine and the Fredenslund criterion. The different versions of the UNIFAC and the ASOG group contribution models were applied.

Susial, Pedro; Estupiñan, Esteban J.; Castillo, Victor D.; Rodríguez-Henríquez, José J.; Apolinario, José C.

2013-10-01

131

Vapor-Liquid Equilibrium in the Mixture Butyl methyl ether C5H12O + C6F14 Tetradecafluorohexane (EVLM1121, LB5737_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Butyl methyl ether C5H12O + C6F14 Tetradecafluorohexane (EVLM1121, LB5737_E)' providing data from direct measurement of mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

132

Vapor-Liquid Equilibrium in the Mixture Tetradecafluorohexane C6F14 + C6H14O Dipropyl ether (EVLM1121, LB5735_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Tetradecafluorohexane C6F14 + C6H14O Dipropyl ether (EVLM1121, LB5735_E)' providing data from direct measurement of mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

133

Vapor-Liquid Equilibrium in the Mixture Tetradecafluorohexane C6F14 + C8H18O Dibutyl ether (EVLM1121, LB5736_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Tetradecafluorohexane C6F14 + C8H18O Dibutyl ether (EVLM1121, LB5736_E)' providing data from direct measurement of mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

134

Vapor-Liquid Equilibrium in the Mixture Tetradecafluorohexane C6F14 + C6H14O Butyl ethyl ether (EVLM1121, LB5738_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Tetradecafluorohexane C6F14 + C6H14O Butyl ethyl ether (EVLM1121, LB5738_E)' providing data from direct measurement of mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

135

Vapor-Liquid Equilibrium in the Mixture Diethyl ether C4H10O + C6F14 Tetradecafluorohexane (EVLM1121, LB5734_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Diethyl ether C4H10O + C6F14 Tetradecafluorohexane (EVLM1121, LB5734_E)' providing data from direct measurement of mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

136

Vapor-Liquid Equilibrium in the Mixture Propan-2-ol C3H8O + C6H14O Diisopropyl ether (EVLM1231, LB5644_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Propan-2-ol C3H8O + C6H14O Diisopropyl ether (EVLM1231, LB5644_E)' providing data from direct measurement of temperature and mole fraction in vapor phase at variable mole fraction in liquid phase and constant pressure.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

137

Vapor-Liquid Equilibrium in the Mixture 2-Methoxyethanol C3H8O2 + C6H14O Diisopropyl ether (EVLM1231, LB5645_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 2-Methoxyethanol C3H8O2 + C6H14O Diisopropyl ether (EVLM1231, LB5645_E)' providing data from direct measurement of temperature and mole fraction in vapor phase at variable mole fraction in liquid phase and constant pressure.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

138

Vapor-Liquid Equilibrium in the Mixture Methanol CH4O + C6H14O2 1-Propoxypropan-2-ol (EVLM1231, LB5714_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Methanol CH4O + C6H14O2 1-Propoxypropan-2-ol (EVLM1231, LB5714_E)' providing data from direct measurement of temperature and mole fraction in vapor phase at variable mole fraction in liquid phase and constant pressure.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

139

Vapor-Liquid Equilibrium in the Mixture Methanol CH4O + C6H13N Cyclohexylamine (EVLM1231, LB5616_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture Methanol CH4O + C6H13N Cyclohexylamine (EVLM1231, LB5616_E)' providing data from direct measurement of temperature and mole fraction in vapor phase at variable mole fraction in liquid phase and constant pressure.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

140

Vapor-Liquid Equilibrium in the Mixture N-Methylmethanamide C2H5NO + C6H6 Benzene (EVLM1111, LB5699_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-liquid Equilibrium in the Mixture N-Methylmethanamide C2H5NO + C6H6 Benzene (EVLM1111, LB5699_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

141

Vapor-Liquid Equilibrium in the Mixture Toluene C7H8 + C7H14 Methylcyclohexane (EVLM1121, LB5742_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Vapor-Liquid Equilibrium in the Mixture Toluene C7H8 + C7H14 Methylcyclohexane (EVLM1121, LB5742_E)' providing data from direct measurement of mole fraction in vapor phase at variable mole fraction in liquid phase and constant temperature.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

142

Effect of ionic liquids on (vapor + liquid) equilibrium behavior of (water + 2-methyl-2-propanol)  

Microsoft Academic Search

Isobaric T, x, y data were reported for ternary systems of {water+2-methyl-2-propanol (tert-butyl alcohol, TBA)+ionic liquid (IL)} at p=100kPa. When the mole fraction of TBA on IL-free basis was fixed at 0.95, measurements were performed at IL mass fractions from 0.6 down to 0.05, in a way of repeated synthesis. The vapor-phase compositions were obtained by analytical methods and the

Lianzhong Zhang; Bingbang Qiao; Yun Ge; Dongshun Deng; Jianbing Ji

2009-01-01

143

Predicting the vapor-liquid equilibrium of hydrocarbon binary mixtures and polymer solutions using predetermined pure component parameters  

NASA Astrophysics Data System (ADS)

In our previous work, a new close-packed lattice model was developed for multi-component system of chain fluids with taking the chain length dependence from Monte-Carlo (MC) simulation results into account. In this work, we further extend this model to describe pressure, volume and temperature (PVT) properties, such as vapor-liquid equilibrium (VLE). To consider the effect of pressure on the phase behavior, the volume change effect is taken into account by introducing holes into the incompressible lattice model with two mixing steps. The corresponding new lattice fluid equation of state (LF-EoS) is applied to predict the thermodynamic properties of pure and binary mixtures of hydrocarbons as well as pure polymer solutions. The results of the proposed model are compared to other predictive approaches based on VLE calculations using predetermined pure model parameters without further adjustment. Thermodynamic properties predicted using the method developed in this work are consistent with the experimental data.

Ryu, Sang Kyu; Bae, Young Chan

2012-05-01

144

Monte Carlo simulation of vapor-liquid equilibrium and critical asymmetry of square-well dimer fluid.  

PubMed

The critical behavior of square-well dimer fluid has been investigated using grand canonical ensemble Monte Carlo simulations combined with a histogram reweighting technique, hyper-parallel tempering and finite-size scaling. The critical temperature and density obtained are T(c)*=1.5495±0.0009 and ?(c)*=0.1473±0.0007, which are 2.5% lower and 5.2% higher than previous results. Coexistence curves both near to and far from the critical point were obtained. The vapor-liquid equilibrium data far from the critical point are consistent with previous results. Simulation results show that the contribution of |t|(1-?) to the coexistence diameter of square-well dimer fluid dominates the critical behavior and the contribution of |t|(2?) is larger than for a hard-core square-well fluid. PMID:22697559

Li, Liyan; Tang, Kaiwei; Wu, Liang; Zhao, Wei; Cai, Jun

2012-06-01

145

Vapor-liquid equilibria for acetone + chloroform + methanol and constituent binary systems at 101. 3 kPa  

Microsoft Academic Search

Vapor-liquid equilibria (VLE) and azeotropic data, which are useful for the design and operation of separation processes, have been observed for many systems. Isobaric vapor-liquid equilibria for acetone + chloroform + methanol and for the constituent binary systems chloroform + methanol and chloroform + acetone were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental data were

Toshihiko Hiaki; Kiyofumi Kurihara; Kazuo Kojima

1994-01-01

146

Prediction of multicomponent vapor-liquid equilibrium with the Wilson equation: effect of the minimization function and of the quality of binary data  

Microsoft Academic Search

Ten objective functions are used in the regression of the vapor-liquid equilibrium (VLE) data for 247 binary systems with the Wilson equation and the obtained parameters are used in the prediction of the VLE behavio of 73 multicomponent systems. All models except model 1 give good results with model 5 being the best one. The results also suggest that the

Norman Silverman; Dimitrios Tassios

1984-01-01

147

A Graphical Simulation of Vapor-Liquid Equilibrium for Use as an Undergraduate Laboratory Experiment and to Demonstrate the Concept of Mathematical Modeling.  

ERIC Educational Resources Information Center

|Demonstrating petroleum engineering concepts in undergraduate laboratories often requires expensive and time-consuming experiments. To eliminate these problems, a graphical simulation technique was developed for junior-level laboratories which illustrate vapor-liquid equilibrium and the use of mathematical modeling. A description of this…

Whitman, David L.; Terry, Ronald E.

1985-01-01

148

Simple apparatus for vapor-liquid equilibrium measurements with data for the binary systems of carbon dioxide with n-butane and isobutane  

Microsoft Academic Search

The authors describe the design, construction, and testing of a simple vapor-liquid equilibrium apparatus designed for measurements in the range 300-500Î at pressures to 150 bar. Data are given for measurements of P, T, x, and y for binary systems of carbon dioxide with n-butane and isobutane in the range 310-394Î.

Lloyd A. Weber

1989-01-01

149

High pressure\\/high temperature vapor liquid equilibrium study of light gases in hydrogen-coal liquid model compound systems using perturbation chromatography  

Microsoft Academic Search

Perturbation chromatography or gas-liquid partition chromatography (GLPC) provides a powerful tool for making physicochemical measurements. In this investigation GLPC was applied to study the vapor-liquid equilibrium behavior of light gases in nonvolatile coal liquid model compound solvents at high temperatures and high pressures. Improvements made in existing GLPC techniques include: the use of a high pressure tandem proportioning pump to

Kragas

1983-01-01

150

Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane + 1,1,1-trifluoroethane (R125/R143a)  

SciTech Connect

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1-trifluoroethane (R143a) was measured by the static method in the temperature range between 273.15 K and 313.15 K. The vapor-liquid coexistence curve near the critical point was measured by observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.4118 and 0.6208 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R143a mixture is correlated as a function of composition.

Higashi, Yukihiro [Iwaki Meisei Univ., Chuodai, Iwaki (Japan). Dept. of Mechanical Engineering

1999-03-01

151

Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane + 1,1,1,2-tetrafluoroethane (R125/R134a)  

SciTech Connect

The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1,2-tetrafluoroethane (R134a) was measured along four isotherms between 283 K and 313 K. The vapor-liquid coexistence curve at constant composition near the mixture critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.2670 and 0.6648 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R134a mixture is correlated as a function of composition.

Higashi, Yukihiro [Iwaki Meisei Univ., Chuodai, Iwaki (Japan). Dept. of Mechanical Engineering

1999-03-01

152

QSPR generalization of activity coefficient models for predicting vapor–liquid equilibrium behavior  

Microsoft Academic Search

Multiphase equilibrium calculations are an integral part of the design and optimization of numerous chemical processes. Several accurate experimental techniques have been developed for measuring phase equilibrium data. However, experimental techniques are time consuming and costly. Hence, a need exists for reliable thermodynamic models capable of giving a priori predictions of the phase behavior of diverse systems in the absence

Devipriya Ravindranath; Brian J. Neely; Robert L. Robinson Jr.; Khaled A. M. Gasem

2007-01-01

153

Isobaric vapor-liquid equilibria of p-xylene + o-xylene and m-xylene + o-xylene systems at 6. 66 and 26. 66 kPa  

SciTech Connect

Vapor-liquid equilibrium data were obtained for systems of o-xylene with p- and m-xylenes at 6.66 and 26.66 kPa. The activity coefficients were found to be thermodynamically consistent. They were equally well correlated with the Margules, Van Laar, Wilson, NRTL, and UNIQUAC equations. The parameters of these equations are given.

Llopis, F.J.; Monton, J.B. (Univ. de Valencia (Spain). Dept. de Ingenieria Quimica)

1994-01-01

154

Vapor–liquid equilibrium of binary mixtures of trichloroethylene with 1-pentanol, 2-methyl-1-butanol and 3-methyl-1-butanol at 100 kPa  

Microsoft Academic Search

Isobaric vapor–liquid equilibria (VLE) have been obtained for the systems trichloroethylene+1-pentanol, trichloroethylene+2-methyl-1-butanol and trichloroethylene+3-methyl-1-butanol at 100 kPa using a dynamic still. The experimental error in temperature is ±0.1 K, in pressure ±0.1 kPa, and in the liquid and vapor mole fraction ±0.001. The three systems satisfy the point-to-point thermodynamic consistency test. All the systems show positive deviations from ideality. The

Ana Dejoz; Vicenta González-Alfaro; Francisco J Llopis; Pablo J Miguel; M. Isabel Vázquez

1999-01-01

155

Vapor–liquid equilibrium of binary mixtures of chlorobenzene with 3-methyl-1-butanol, 3-methyl-2-butanol and 2-methyl-2-butanol, at 100 kPa  

Microsoft Academic Search

Isobaric vapor–liquid equilibria have been obtained for the systems 3-methyl-1-butanol+chlorobenzene, 3-methyl-2-butanol+chlorobenzene and 2-methyl-2-butanol+chlorobenzene at 100 kPa, using a dynamic still. The experimental error in temperature is ±0.1 K, in pressure ±0.1 kPa, and in the liquid and vapor mole fraction ±0.001. The three systems satisfy the point-to-point thermodynamic consistency test. All the systems show positive deviations from ideality. The data

Ana Dejoz; Vicenta González-Alfaro; Francisco J Llopis; Pablo J Miguel; M. Isabel Vázquez

1998-01-01

156

Description of the vapor–liquid equilibrium in binary refrigerant\\/lubricating oil systems by means of an extended Flory–Huggins model  

Microsoft Academic Search

In the present work, the extended Flory–Huggins equation is applied to describe the vapor–liquid equilibrium in binary mixtures usually used in refrigerating cycle machines and constituted by a fluorinated refrigerant (CFC) and a lubricating oil.With the purpose of testing the model, some isothermal measurements of equilibrium pressure have been carried out for mixtures with different CFC compositions in oil related

R Tesser; E Musso; M Di Serio; G Basile; E Santacesaria

1999-01-01

157

Isothermal vapor–liquid equilibrium data for the carbon dioxide (R744) + decafluorobutane (R610) system at temperatures from 263 to 353 K  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium data are presented for the carbon dioxide (CO2)+decafluorobutane (C4F10) system. Measurements were performed for seven isotherms (three isotherms below and four above the critical temperature of CO2) ranging from 263.15 to 352.98K, with pressure ranging from 0.0727 to 6.8628MPa. The measurements were undertaken using a “static-analytic” type apparatus, with sampling of the equilibrium phases via pneumatic capillary

Alain Valtz; Xavier Courtial; Erik Johansson; Christophe Coquelet; Deresh Ramjugernath

2011-01-01

158

High-pressure density and vapor–liquid equilibrium for the binary systems carbon dioxide–ethanol, carbon dioxide–acetone and carbon dioxide–dichloromethane  

Microsoft Academic Search

An apparatus for the measurement of vapor–liquid equilibrium (VLE, P–T–x) 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

159

The influence of equilibrium chemical reactions on vapor-liquid phase diagrams  

SciTech Connect

Phase diagrams for simultaneous chemical reaction and phase equilibrium are presented for ideal and non-ideal systems. It is shown that reactive-azeotropes can occur for ideal mixtures. The conditions for formation of reactive-azeotropes in constant volatility systems are derived. These conditions show that for such systems reactive-azeotropes can occur only when the volatiles of the reactants are either all higher or all lower than the volatilities of the products.

Barbosa, D.; Doherty, M.F.

1986-01-01

160

A molecular model for correlating vapor-liquid equilibrium of propane+hydrocarbon mixtures  

Microsoft Academic Search

Simple analytical expressions are proposed for the calculation of the equilibrium pressure and the mole fractions of both\\u000a liquid and vapor phases of propane+hydrocarbon binary mixtures. The new proposed expressions are based on a simple analytical\\u000a expression for the vapor pressure of pure non-polar fluids, which, for a given temperature, only requires as input the values\\u000a of the Lennard-Jones molecular

Claudio A. FaÚndez; Luis E. Tamblay; José O. Valderrama

2004-01-01

161

Thermodynamic modeling of the vapor–liquid equilibrium of the CO 2\\/H 2O mixture  

Microsoft Academic Search

In order to evaluate the feasibility of CO2 sequestration in geological formations detailed knowledge of the mutual solubilities of the CO2\\/H2O system is required. In this work we employ three models, which all involve the well-known Peng–Robinson equation of state, to study the CO2\\/H2O phase equilibrium, with emphasis on the solubility of CO2 in the aqueous phase and the solubility

Georgia D. Pappa; Christophoros Perakis; Ioannis N. Tsimpanogiannis; Epaminondas C. Voutsas

2009-01-01

162

Measurement and Correlation of Vapor-Liquid Equilibrium for a Cyclohexene-Cyclohexanol Binary System at 101.3 kPa  

Microsoft Academic Search

Many by-products are generated in the process of oxidizing cyclohexene to produce 1,2-epoxycyclohexane by hydrogen peroxide, including cyclohexanol, cyclohexanone, etc. To obtain high-purity 1,2-epoxycyclohexane, the by-products and unreacted cyclohexene must be removed through rectification, in which the vapor-liquid equilibrium (VLE) data of the system are needed. In this study, the VLE data of cyclohexene-cyclohexanol system were studied at 101.3 kPa

Xunqiu WANG; Xinliang ZHUANG; Shasha YUN; Jingbo CHEN; Denggao JIANG

2011-01-01

163

A recirculation apparatus for vapor–liquid equilibrium measurements of refrigerants. Binary mixtures of R600a, R134a and R236fa  

Microsoft Academic Search

An apparatus for the measurement of vapor–liquid equilibria (P–T–x–y) data of refrigerant systems was designed, built and tested. The recirculation method was used and the vapor phase was forced through the liquid phase by a magnetic pump. The thermodynamic equilibrium was reached in a visual cell with an internal volume of 50 cm3. The compositions of the phases were analyzed

Sergio Bobbo; Roman Stryjek; Nicola Elvassore; Alberto Bertucco

1998-01-01

164

(Vapor + liquid) equilibrium data for (carbon dioxide + 1,1-difluoroethane) system at temperatures from (258 to 343) K and pressures up to about 8 MPa  

Microsoft Academic Search

Accurate thermo-physical data are of utmost interest for the development of new efficient refrigeration systems. Carbon dioxide (R744) and 1,1-difluoroethane (R152a) are addressed here. Isothermal (vapor+liquid) equilibrium data are reported herein for (R744+R152a) binary system in the (258–343) K temperature range and in the (0.14 to 7.65) MPa pressure range. A reliable “static-analytic” method taking advantage of two online ROLSI™

Hakim Madani; Alain Valtz; Christophe Coquelet; Abdeslam Hassen Meniai; Dominique Richon

2008-01-01

165

Vapor-liquid equilibrium for R-32 and R-410A mixed with a polyol ester: non-ideality and local composition modeling  

Microsoft Academic Search

Vapor-liquid equilibrium (VLE) data were obtained over a wide range of mixture compositions and saturation conditions for difluoromethane (R-32) mixed with a polyol ester oil (POE). These data were correlated using the following local-composition models from the literature: Wilson, Heil, Wang and Chao, Tsuboka and Katayama, NRTL and UNIQUAC. The results were used to evaluate the suitability of these models

C. Burton; A. M. Jacobi; S. S. Mehendale

1999-01-01

166

Evaluating cubic equations of state for calculation of vapor–liquid equilibrium of CO 2 and CO 2-mixtures for CO 2 capture and storage processes  

Microsoft Academic Search

Proper solution of vapor liquid equilibrium (VLE) is essential to the design and operation of CO2 capture and storage system (CCS). According to the requirements of engineering applications, cubic equations of state (EOS) are preferable to predict VLE properties. This paper evaluates the reliabilities of five cubic EOSs, including PR, PT, RK, SRK and 3P1T for predicting VLE of CO2

H. Li; J. Yan

2009-01-01

167

An extended corresponding-states model for predicting thermodynamic properties of N 2 -Ar-O 2 mixtures including vapor-liquid equilibrium  

Microsoft Academic Search

A formulation developed previously for the prediction of the thermodynamic properties of single-phase states of binary and ternary mixtures in the nitrogen-argon-oxygen system has been revised to include the calculation of vapor-liquid equilibrium (VLE) properties. The model is based on the theory of extended corresponding states with van der Waals mixing rules. Binary interaction parameters have been determined with single-phaseP-p-T

W. P. Clarke; R. T. Jacobsen; E. W. Lemmon; S. G. Penoncello; S. W. Beyerlein

1994-01-01

168

Vapor–liquid equilibrium ratios for hexane at infinite dilution in ethylene+impact polypropylene copolymer and propylene+impact polypropylene copolymer  

Microsoft Academic Search

Vapor–liquid equilibrium ratios (Kw1? values) for hexane at infinite dilution in propylene+impact polypropylene copolymer (ICP–PP) and ethylene+ICP–PP systems were measured at temperatures 323.2, 343.2 and 363.2 K and pressures up to 2.4 MPa using a chromatographic technique. The solubilities of propylene in polypropylene and those of propylene, ethylene, and hexane in ICP–PP were measured. The PVT properties of the polypropylene

Yoshiyuki Sato; Akio Tsuboi; Atsushi Sorakubo; Shigeki Takishima; Hirokatsu Masuoka; Takeshi Ishikawa

2000-01-01

169

Vapor–liquid equilibrium data and critical points for the system H 2S+COS. Extension of the PSRK group contribution equation of state  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium data for the binary system hydrogen sulfide+carbonyl sulfide were measured in the temperature range from 232 to 293 K using the static-synthetic technique. From the isothermal P?x data, the azeotropic conditions were derived. The critical line of this system was visually detected in a flow apparatus. Interaction parameters for this binary system were fitted simultaneously to all

Patricia Guilbot; Pascal Théveneau; Abdelatif Baba-Ahmed; Sven Horstmann; Kai Fischer; Dominique Richon

2000-01-01

170

Vapor-liquid equilibrium data for methanol, ethanol, methyl acetate, ethyl acetate, and o-xylene at 101.3 kPa  

SciTech Connect

Vapor-liquid equilibrium was measured for the binary systems methanol + o-xylene, ethanol + o-xylene, methyl acetate + o-xylene and ethyl acetate + o-xylene, and for the multicomponent mixtures methanol + methyl acetate + o-xylene, ethanol + ethyl acetate + o-xylene, and methanol + ethanol + methyl acetate + ethyl acetate + o-xylene at 101.3 kPa. The Wilson and Van Laar models were compared with the UNIFAC method. Results show that the correlation was satisfactory.

Costa-Lopez, J.; Garvin, A.; Espana, F.J. [Barcelona Univ. (Spain). Chemical Engineering Dept.

1995-09-01

171

Vapor–Liquid Equilibrium  

Microsoft Academic Search

\\u000a Every time a fluid is confined at a nanometer scale, the predominance of the fluid–substrate interactions strongly distorts\\u000a its intrinsic properties. For instance, it is observed that the amount of fluid adsorbed in a nanoporous substrate is not\\u000a a single-valued function of the chemical potential and may present a hysteresis. Understanding this phenomenon is a fundamental\\u000a issue since it appears

Joël Puibasset

172

Vapor-liquid equilibrium model for a partially miscible multicomponent system: isopropanol-acetone-ethanol-n-butanol-water  

SciTech Connect

Normal butanol, a potential diesel fuel additive, can be produced by the fermentation of paper pulp waste streams by Clostridia with isopropanol, acetone, and ethanol produced as byproducts. To design a distillation process for the recovery of n-butanol from fermentation broth, the vapor-liquid equilibria for the multicomponent system isopropanol-acetone-ethanol-n-butanol-water were modeled using Wilson equations to predict liquid activity coefficients. An extra parameter was added to the Wilson correlation to allow for the partial miscibility between butanol and water. The accuracy of the model was tested by comparing the predicted vapor composition with experimentally obtained values in the immiscible region. Even with the extra parameter, the model did not predict a miscibility gap between n-butanol and water, and the vapor-liquid equilibria were predicted with an accuracy of +- 0.15 mol fraction.

Chronis, J.H.; Amrhein, M.

1980-07-01

173

Correlation and prediction of salt effects on vapor–liquid equilibrium in alcohol–water–salt systems  

Microsoft Academic Search

A modification of the solvation model of Ohe is proposed for the calculation of vapor–liquid equilibria (VLE) in alcohol–water–salt systems. The modified method employs the Bromley equation to calculate the activity of water in salt solutions, and a one-parameter empirical expression to calculate the activity of the alcohol. The single parameter is obtained by fitting ternary alcohol–water–salt data. The method

Tongfan Sun; Kerry R. Bullock; Amyn S. Teja

2004-01-01

174

Vapor-liquid equilibrium model for a partially miscible multicomponent system: isopropanol-acetone-ethanol-n-butanol-water  

Microsoft Academic Search

Normal butanol, a potential diesel fuel additive, can be produced by the fermentation of paper pulp waste streams by Clostridia with isopropanol, acetone, and ethanol produced as byproducts. To design a distillation process for the recovery of n-butanol from fermentation broth, the vapor-liquid equilibria for the multicomponent system isopropanol-acetone-ethanol-n-butanol-water were modeled using Wilson equations to predict liquid activity coefficients. An

J. H. Chronis; M. Amrhein

1980-01-01

175

Isobaric vapor-liquid equilibria in the binary systems propyl bromide-i-butanol, propyl bromide-1-chlorobutane and 1-chlorobutane-methyl ethyl ketone  

Microsoft Academic Search

Vapor-liquid equilibria at 101.3 kPa have been determined for binary systems propyl bromide-i-butanol, propyl bromide-1-chlorobutane and 1-chlorobutane-methyl ethyl ketone. The binary systems propyl bromide-i-butanol and 1-chlorobutane-methyl ethyl ketone exhibit positive deviations from ideal behavior while the binary system propyl bromide-1-chlorobutane behaves ideally. The activity coefficients and boiling point of the solution were correlated with its composition by the Redlich-Kister and

Jaime Wisniak

1995-01-01

176

Measurement of Vapor-Liquid Equilibrium for the DME + Diisopropyl Ether Binary System and Correlation for the DME + CO2 + Diisopropyl Ether Ternary System  

NASA Astrophysics Data System (ADS)

Vapor-liquid equilibrium (VLE) data have been measured with a static-type VLE apparatus for the dimethyl ether (DME)-diisopropyl ether (DIPE) binary system at five temperatures within the range from 293.04 K to 352.70 K. An isothermal correlation for the experimental data has been carried out based on the Peng-Robinson equation of state. The regressed binary interaction parameters were used to estimate VLE for the DME-CO2-DIPE ternary system at 298.15 K. From the study, it is demonstrated that DIPE is an excellent absorbent for separation in the DME synthesis process from syngas.

Wu, Xianghong; Du, Xiaojie; Zheng, Danxing

2010-02-01

177

Vapor–liquid equilibrium in aqueous systems containing poly(vinylpyrrolidone) and sodium citrate at different temperatures—Experimental and modeling  

Microsoft Academic Search

The improved isopiestic method have been used to obtain activities of water for poly(vinylpyrrolidone) (PVP)+sodium citrate (Na3Cit)+H2O and Na3Cit+H2O systems at 298.15, 308.15 and 318.15K. From these measurements, values of the vapor pressure of solutions were determined. The effect of temperature on the vapor–liquid equilibrium of PVP+Na3Cit+H2O systems has been studied. It was found that, the slope of constant water

Rahmat Sadeghi

2006-01-01

178

Vapor-liquid equilibria of binary and ternary mixtures of cyclohexane, 3-methyl-2-butanone, and octane at 101.3 kPa  

SciTech Connect

Vapor-liquid equilibria were measured at 101.3 kPa for the three binary and one ternary mixtures of cyclohexane, 3-methyl-2-butanone, and octane. The isobaric T-x-y data were reported, including an azeotropic point for the binary mixture cyclohexane + 3-methyl-2-butanone. The virial equation of state truncated after the second coefficient was used to calculate the vapor-phase fugacity coefficients. The Tsonopoulos correlation equation was applied to determine the second virial coefficients. Various activity coefficient models of the Wilson, the NRTL, and the UNIQUAC equations were used to correlate the binary experimental vapor-liquid equilibrium results. Optimally-fitted binary parameters of the activity coefficient models were obtained and those parameters of the NRTL model were employed to predict the ternary vapor-liquid equilibria. Satisfactory results were presented for the correlation and prediction of the vapor-liquid equilibrium data on binary and ternary mixtures.

Chen, C.C.; Tang, M.; Chen, Y.P. [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Chemical Engineering

1996-05-01

179

Isothermal vapor--liquid equilibrium data for binary systems at high pressures; Carbon dioxide-methanol, carbon dioxide-ethanol, carbon dioxide1-propanol, methaneethanol, methane1-propanol, ethaneethanol, and ethane1-propanol systems  

Microsoft Academic Search

This paper reports an experiment conducted on isothermal vapor-liquid equilibrium data for binary systems at high pressure. Carbon dioxide-methanol, carbon dioxide-ethanol, carbon dioxide-1-propanol, methane-ethanol, methane-1-propanol, ethane-ethanol, and ethane-1-propanol were measured by a new static phase equilibrium apparatus at 313.4 and 333,4 K.

Kazuhiko Suzuki; Haruhusa Sue; Masahiro Itou; Richard L. Smith; Hiroshi Inomata; K. Aria; Shozaburo Saito

1990-01-01

180

Vapor-liquid equilibria for acetone + chloroform + methanol and constituent binary systems at 101. 3 kPa  

SciTech Connect

Vapor-liquid equilibria (VLE) and azeotropic data, which are useful for the design and operation of separation processes, have been observed for many systems. Isobaric vapor-liquid equilibria for acetone + chloroform + methanol and for the constituent binary systems chloroform + methanol and chloroform + acetone were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental data were correlated with the extended Redlich-Kister and Wilson equations. The data were best correlated and completely calculated for the ternary and three binary azeotropic data using the extended Redlich-Kister equation.

Hiaki, Toshihiko (Nihon Univ., Chiba (Japan). Dept. of Industrial Chemistry); Kurihara, Kiyofumi; Kojima, Kazuo (Nihon Univ., Tokyo (Japan). Dept. of Industrial Chemistry)

1994-10-01

181

On the Re-engineered TIP4P Water Models for the Preduction of Vapor-Liquid Equilibrium  

SciTech Connect

We perform extensive Gibbs Ensemble Monte Carlo simulations to study the capability of some recently re-parameterizations of the original TIP4P model intended to predict accurately the vapor-liquid coexistence envelope of water, its critical point, and its temperature dependence for the vapor pressure and second virial coefficient, and complement this analysis with the characterization of some specific crystalline faces of ice. We also disclose some trends between the resulting dipole moment of the models and the Lennard-Jones parameters, the location of the negative charge, as well as the estimated critical temperature. Finally, we discuss the inability of these models to predict accurately and simultaneously the melting temperature and the temperature of maximum density.

Chialvo, Ariel A [ORNL; Bartok, A. [Eotvos University, Budapest, Hungary; Baranayai, A. [Eotvos University, Budapest, Hungary

2006-01-01

182

Vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H14O Diisopropyl ether (EVLM1311, LB5741_E)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,2-Dichloroethane C2H4Cl2 + C6H14O Diisopropyl ether (EVLM1311, LB5741_E)' providing data from direct measurement of pressure at variable temperature and constant mole fraction in liquid phase.

Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

183

Proposal of a minimal expression for nonlinear fuzzy approximation for the vapor liquid equilibrium VLE of the ethanol-water system at 560 mm Hg using defuzification based on Boolean Relations DBR and Singleton model  

Microsoft Academic Search

A novel methodology is presented in order to obtain a nonlinear correlation the vapor liquid equilibrium VLE of ethanol-water system at Bogota conditions, using as nonlinear approximators the defuzification based on Boolean relations DBR, based on data obtained by thermodynamical correlations and compared with polynomial and Sugeno model in order to apply to the simulation of the distillation process.

M. J. J. Soriano; Francisco Jose de Caldas

2009-01-01

184

Vacuum freezing type ice slurry production using ethanol solution 1st report: Measurement of vapor–liquid equilibrium data of ethanol solution at 20 °C and at the freezing temperature  

Microsoft Academic Search

In this study, an original method for the production of ice slurry from ethanol solution without using a refrigerator is proposed. This system has advantages compared with similar existing systems using materials other than ethanol solution. In this paper, the vapor–liquid equilibrium data of ethanol solution at 20°C and at the freezing temperature are measured, which is necessary to calculate

Tatsunori Asaoka; Akio Saito; Seiji Okawa; Tetsuya Ito; Naoki Izumi

2009-01-01

185

Vapor-liquid equilibrium of the Mg(NO/sub 3/)/sub 2/-HNO/sub 3/-H/sub 2/O system  

SciTech Connect

The vapor-liquid equilibrium of the Mg(NO/sub 3/)/sub 2/-HNO/sub 3/-H/sub 2/O system in concentrations of 0 to 70 wt % Mg(NO/sub 3/)/sub 2/ and 0 to 75 wt % HNO/sub 3/ at atmospheric pressure was correlated by two approaches. One was based on a dissociation equilibrium expression in which the activities of the reacting species (HNO/sub 3/, NO/sub 3//sup -/, and H/sup +/) were approximated with mole fractions. The activity coefficients of the undissociated HNO/sub 3/ and H/sub 2/O were correlated as functions of the concentrations of magnesium nitrate and nitric acid by second-order polynomials. The average absolute difference between predicted and experimental values was 8% for the mole fraction of acid in the vapor and 8/sup 0/K for the bubble-point temperature. The second approach was to correlate the mean ionic rational activity coefficient of water with a form of the excess Gibbs energy composed of two terms. One term, a function of the ionic strength, accounts for the coulombic (ionic) interactions; the other term accounts for the non-coulombic (molecular) interactions. The average absolute difference between predicted and experimental values was 9% for the mole fraction of acid in the vapor, and 10/sup 0/K for the bubble-point temperature.

Thompson, B.E.; Derby, J.J.; Stalzer, E.H.

1983-06-01

186

Vapor–liquid equilibrium for model Fischer–Tropsch waxes (hexadecane, 1-hexadecene, and 1-hexadecanol) in supercritical hexane  

Microsoft Academic Search

Vapor and liquid equilibrium compositions have been measured for the hexane+1-hexadecene system at 472.1, 524.7, and 572.5 K and at pressures ranging from 7.9 to 40.1 bar. A continuous-flow apparatus was used both to minimize 1-hexadecene polymerization and to measure the low 1-hexadecene concentrations in the vapor phase. Mixture critical pressures and compositions were measured for the two temperatures above

Patrick C Joyce; Bryon E Leggett; Mark C Thies

1999-01-01

187

High pressure/high temperature vapor liquid equilibrium study of light gases in hydrogen-coal liquid model compound systems using perturbation chromatography  

SciTech Connect

Perturbation chromatography or gas-liquid partition chromatography (GLPC) provides a powerful tool for making physicochemical measurements. In this investigation GLPC was applied to study the vapor-liquid equilibrium behavior of light gases in nonvolatile coal liquid model compound solvents at high temperatures and high pressures. Improvements made in existing GLPC techniques include: the use of a high pressure tandem proportioning pump to give precise control of the carrier gas flow rate and low pressure drops; a high pressure ionization chamber to detect the injection of very dilute radioactive sample gases; and the use of a microcomputer to provide instantaneous integration and very precise retention times of the chromatographic peaks. Infinite dilution K-values for methane, ethane, propane, n-butane, carbon dioxide, and hydrogen sulfide in hydrogen-dibenzofuran systems were obtained at 100 and 125 C and up to 800 psia. Infinite dilution K-values for the same light gases in hydrogen-9-methylanthracene systems were obtained at 100, 125, 150, 175, and 200 C and up to 3000 psia. Henry's constants were determined for the light gases in 9-methylanthracene. Second cross virial coefficients and vapor phase infinite dilution fugacity coefficients were calculated for methane, ethane, propane, and n-butane in hydrogen. These results were combined with the experimental K-value measurements to obtain Henry's constants in hydrogen-9-methylanthracene mixtures of fixed liquid compositions. Infinite dilution heats of solution of the solute gases in the mixtures were calculated.

Kragas, T.K.

1983-01-01

188

High pressure vapor–liquid equilibrium data for the systems carbon dioxide\\/2-methyl-1-propanol and carbon dioxide\\/3-methyl-1-butanol at 288.2, 303.2 and 313.2 K  

Microsoft Academic Search

In this work, we report vapor–liquid equilibrium data for the systems carbon dioxide (CO2)\\/iso-butanol and CO2\\/iso-pentanol at 288.2, 303.2 and 313.2K, and for pressures up to the critical point. The interaction parameters for the Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR) equations of state (EOS) that best fit the experimental results are also given.

Marta Vázquez da Silva; Domingos Barbosa

2002-01-01

189

Prediction of vapor–liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part I: Application to H 2O–CO 2 system  

Microsoft Academic Search

Molecular based equations of state (EOS) are attractive because they can take into account the energetic contribution of the main types of molecular interactions. This study models vapor–liquid equilibrium (VLE) and PVTx properties of the H2O–CO2 binary system using a Lennard-Jones (LJ) referenced SAFT (Statistical Associating Fluid Theory) EOS. The improved SAFT-LJ EOS is defined in terms of the residual

Rui Sun; Jean Dubessy

2010-01-01

190

Vapor–liquid equilibrium for binary system of diethyl sulfide + cyclohexane at 353.15 and 343.15 K and diethyl sulfide + 2-ethoxy-2-methylpropane at 343.15 and 333.15 K  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium (VLE) for diethyl sulfide+cyclohexane were measured at 353.15 and 343.15K and diethyl sulfide+2-ethoxy-2-methylpropane were measured at 343.15 and 333.15K with a circulation still. All systems exhibit slight positive deviation from ideality. No azeotropic behavior was found in any of the systems studied. The experimental results were correlated with the Wilson model with temperature dependent parameters and also

Erlin Sapei; Anna Zaytseva; Petri Uusi-Kyyny; Kari I. Keskinen; Juhani Aittamaa

2007-01-01

191

Vapor–Liquid Equilibrium Data for the Sulfur Dioxide (SO 2 ) + Difluoromethane (R32) System at Temperatures from 288.07 to 403.16 K and at Pressures up to 7.31 MPa  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium data have been measured for the binary system R32 (difluoromethane) + SO2 at eight temperatures between 288.07 and 403.16 K, and at pressures in the range 0.417–7.31 MPa. The experimental method used in this work is of the static–analytic type, taking advantage of two pneumatic capillary samplers (RolsiTM, Armines’ patent) developed in the CENERG\\/TEP laboratory. The data were

A. Valtz; C. Coquelet; D. Richon

2004-01-01

192

Thermodynamic modeling of vapor–liquid equilibrium of binary systems ionic liquid + supercritical {CO 2 or CHF 3} and ionic liquid + hydrocarbons using Peng–Robinson equation of state  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) data from literature for binary systems involving several ionic liquids were correlated. The Peng–Robinson equation of state, coupled with the van der Waals and Wong–Sandler mixing rules, was used as the thermodynamic model to evaluate the fugacity coefficients. The UNIQUAC and NRTL models were used to calculate the excess Gibbs free energy in the Wong–Sandler mixing rule.

Víctor H. Álvarez; Martín Aznar

2008-01-01

193

Vapor-liquid equilibria for the binary systems of 1-butanol with some halohydrocarbons at 40.0 and 101.3 kPa  

SciTech Connect

Isobaric vapor-liquid equilibrium measurements at 40.0 and 101.3 kPa are reported for 1-butanol + chlorocyclohexane, + chlorobenzene, + bromocyclohexane, + bromobenzene. Some of the studied systems show minimum temperature azeotropes. The experimental data were tested for thermodynamic consistency and satisfactorily correlated with the Margules, Van Laar, Wilson, NRTL, and UNIQUAC equations. Predictions with the UNIFAC method and ASOG method were also obtained.

Artigas, H.; Lafuente, C.; Cea, P.; Royo, F.M.; Urieta, J.S. [Univ. de Zaragoza (Spain)

1997-01-01

194

Vapor–liquid equilibria for the ternary system benzene+ n-heptane+ N, N-dimethylformamide at 101.33 kPa  

Microsoft Academic Search

Isobaric vapor–liquid-equilibrium (VLE) data at 101.33kPa for the system formed by benzene, n-heptane and N,N-dimethylformamide (DMF) are reported. Data reduction has been carried out through Wilson, NRTL, and UNIQUAC thermodynamic models for correlating the liquid-phase activity coefficients. Activity coefficients of the components in the mixture indicate positive deviations from Raoult’s law. Experimental results show that DMF is a good extractive

Beatriz Blanco; Maria Teresa Sanz; Sagrario Beltrán; José Luis Cabezas; José Coca

2000-01-01

195

Vapor–liquid equilibria of the binary mixtures of tetrahydrofuran with 2,2,4-trimethylpentane, methylcyclohexane and n-heptane at 101.3 kPa  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) data have been measured at 101.3kPa for three binary mixtures of tetrahydrofuran with 2,2,4-trimethylpentane, methylcyclohexane and n-heptane. The isobaric T–x–y data have been reported and the thermodynamic consistency has been examined. The non-ideal behavior of the vapor phase has been considered by using the Soave–Redlich–Kwong (SRK) equation of state in calculating the fugacity coefficient. The Wilson, NRTL

Tz-Bang Du; Muoi Tang; Yan-Ping Chen

2001-01-01

196

Vapor–liquid equilibria for 1,1,2,3,3,3-hexafluoropropyl, 2,2,2-trifluoroethyl ether with several organic solvents  

Microsoft Academic Search

The isobaric vapor–liquid equilibria (VLE) for the binary systems 1,1,2,3,3,3-hexafluoropropyl, 2,2,2-trifluoroethyl ether (HFE-449mec-f), i.e. CF3CHFCF2OCH2CF3, + methanol, ethanol, 2-propanol or trans-1,2-dichloroethylene have been measured at 101.3kPa. The measurements were made in an equilibrium still, developed in a previous study, with circulation of both the vapor and liquid phase. The four binary isobaric systems of the HFE-449mec-f with organic solvents exhibit

Toshihiko Hiaki; Makiko Nanao; Shingo Urata; Junji Murata

2002-01-01

197

Vapor-liquid equilibrium data for the propane/-, n-butane/-, isobutane/-, and propylene/isopropyl fluoride systems at 30 and 50 /sup 0/C  

SciTech Connect

This paper presents vapor-liquid equillibrium data at 30 and 50 /sup 0/C for the binary systems of isopropyl fluoride + propane, propylene, isobutane, and n-butane. The isopropyl fluoride/butane systems exhibit positive azeotropes. The computed, equimolar Gibbs free energy for the propylene system is roughly one-half that of the three alliphatic systems.

Parrish, W.R.; Sitton, D.M.

1982-07-01

198

Vapor-Liquid Equilibrium of Carbon Dioxide with Isobutane and n-Butane: Modified Leung-Griffiths Correlation and Data Evaluation.  

National Technical Information Service (NTIS)

The Leung-Griffiths model as modified by Moldover and Rainwater is used to correlate high-pressure vapor-liquid equilibria of carbon dioxide with n-butane and isobutane. Model correlations are compared against 10 independent experimental sources for these...

J. C. Rainwater H. Ingham J. J. Lynch

1990-01-01

199

Vapor–liquid equilibrium in systems (water + organic solvent + salt) at low water concentrations but high ratios of salt to water: experimental results and modeling  

Microsoft Academic Search

Water-free organic solvents are often required in chemical processes. It is common practice to dewater organic solvents by distillation. The operation of such distillation equipment often shows that the design specifications are not met as for example the amount of energy required to remove water to very small concentrations is much higher than expected from reliable data for the vapor–liquid

Günter Uhrig; Xiaoyan Ji; Gerd Maurer

2005-01-01

200

Vapor-liquid equilibria for 1,1,1-trifluoro-2-(2,2,2-trifluoroethoxy)ethane +2-methyl-2-propanol and pentane+1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane system  

Microsoft Academic Search

Isobaric vapor-liquid equilibrium (VLE) for two binary systems of 1,1,1-Trifluoro-2-(2,2,2-trifluoroethoxy) ethane+2-methyl-2-propanol\\u000a and pentane+1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane system have been measured at 101.3 kPa. The measurements were\\u000a made in an equilibrium still, developed in a previous study, with circulation of both the vapor and liquid phases. The binary\\u000a isobaric systems exhibit minimum boiling azeotropes. The thermodynamic consistencies of the experimental data were good by

Toshihiko Hiaki; Shingo Fujita; Tomoya Tsuji; Shingo Urata; Junji Mizukado

2003-01-01

201

Liquid–liquid equilibrium data of water with neohexane, methylcyclohexane, tert-butyl methyl ether, n-heptane and vapor–liquid–liquid equilibrium with methane  

Microsoft Academic Search

Liquid–liquid equilibrium (LLE) data for non-aqueous liquid (neohexane [NH], tert-butyl methyl ether [TBME], methylcyclohexane [MCH], or n-heptane [nC7]) and water have been measured under atmospheric pressure at 275.5, 283.15, and 298.15K. It was found that TBME is the most water soluble followed by NH, MCH, and nC7. As the temperature increased, the solubility of the non-aqueous liquids (NALs) in water

R. Susilo; J. D. Lee; P. Englezos

2005-01-01

202

Vapor–liquid equilibrium data for the propane+1,1,1,2,3,3,3-heptafluoropropane (R227ea) system at temperatures from 293.16 to 353.18 K and pressures up to 3.4 MPa  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium (VLE) data for the propane+1,1,1,2,3,3,3-heptafluoropropane (R227ea) binary system were measured at 293.16, 303.14, 313.14, 333.15, 343.16 and 353.18K and pressures up to 3.5MPa. The experimental method, used in this work, is of the static-analytic type. It takes advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the Cenerg\\/TEP laboratory. The peculiarity of R227ea–propane binary system

A Valtz; C Coquelet; A Baba-Ahmed; D Richon

2002-01-01

203

Vapor–liquid equilibrium for binary system of thiophene + 2,2,4-trimethylpentane at 343.15 and 353.15 K and thiophene + 2-ethoxy-2-methylpropane at 333.15 and 343.15 K  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium (VLE) for thiophene+2,2,4-trimethylpentane were measured at 343.15 and 353.15K and thiophene+2-ethoxy-2-methylpropane were measured at 333.15 and 343.15K with a circulation still. Maximum pressure azeotropes were found in thiophene+2,2,4-trimethylpentane systems, whereas thiophene+2-ethoxy-2-methylpropane systems exhibit slight positive deviation from ideality. No azeotropic behavior was found in thiophene+2-ethoxy-2-methylpropane systems. The experimental results were correlated with the Wilson model and also

Erlin Sapei; Anna Zaytseva; Petri Uusi-Kyyny; Kari I. Keskinen; Juhani Aittamaa

2007-01-01

204

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

205

Densities and vapor-liquid equilibria in binary mixtures formed by propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol at 160.0 kPa  

SciTech Connect

Densities and excess volumes were determined at 298.15 K for propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol. The results of those quantities were then correlated to get the concentrations of vapor-liquid equilibrium obtained isobarically at 160 kPa for the same mixtures. Two mixtures show azeotropes: for propyl methanoate (1) + ethanol (2), x{sub 1} = 0.443 at T = 358.7 K; and for propyl methanoate (1) + propan-1-ol (2), x{sub 1} = 0.762 at T = 368.2 K. The mixtures are thermodynamically consistent, and the predictions made using several group-contribution models are satisfactory.

Falcon, J.; Ortega, J.; Gonzalez, E. [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica

1996-07-01

206

Prediction of vapor-liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part I: Application to H 2O-CO 2 system  

NASA Astrophysics Data System (ADS)

Molecular based equations of state (EOS) are attractive because they can take into account the energetic contribution of the main types of molecular interactions. This study models vapor-liquid equilibrium (VLE) and PVTx properties of the H 2O-CO 2 binary system using a Lennard-Jones (LJ) referenced SAFT (Statistical Associating Fluid Theory) EOS. The improved SAFT-LJ EOS is defined in terms of the residual molar Helmholtz energy, which is a sum of four terms representing the contributions from LJ segment-segment interactions, chain-forming among the LJ segments, short-range associations and long-range multi-polar interactions. CO 2 is modeled as a linear chain molecule with a constant quadrupole moment, and H 2O is modeled as a spherical molecule with four association sites and a dipole moment. The multi-polar contribution to Helmholtz energy, including the dipole-dipole, dipole-quadrupole, and quadrupole-quadrupole contribution for H 2O-CO 2 system, is calculated using the theory of Gubbins and Twu (1978). Six parameters for pure H 2O and four parameters for pure CO 2 are needed in our model. The Van der Waals one-fluid mixing rule is used to calculate the Lennard-Jones energy parameter and volume parameter for the mixture. Two or three binary parameters are needed for CO 2-H 2O mixtures, which are evaluated from phase equilibrium data of the binary system. Comparison with the experimental data shows that our model represents the PVT properties of CO 2 better than other SAFT EOS without a quadrupole contribution. For the CO 2-H 2O system, our model agrees well with the vapor-liquid equilibrium data from 323-623 K. The average relative deviation for CO 2 solubility (expressed in mole fraction) in water is within 6%. Our model can also predict the PVTx properties of CO 2-H 2O mixtures up to 1073 K and 3000 bar. The good performance of this model indicates that: (1) taking account of the multi-polar contribution explicitly improves the agreement of calculated properties with experimental data at high temperatures and high pressures, (2) the molecular-based EOS with just a few parameters fit to data in the sub-critical region can predict the thermodynamic properties of fluids over a wide range of P- T conditions.

Sun, Rui; Dubessy, Jean

2010-04-01

207

Vapor-liquid critical curve of the system ethane + 2-methylpropane  

SciTech Connect

The vapor-liquid critical curve of the binary system ethane + 2-methylpropane was determined from the critical temperature of ethane up to the critical temperature of 2-methylpropane. The results are compared with vapor-liquid equilibrium data reported earlier on this system and with the critical curve that is predicted for this system from the Peng-Robinson equation of state.

deLoos, T.W.; vanderKool, H.J.; Ott, P.L.

1986-04-01

208

Vaporized liquid fuel combustion apparatus  

Microsoft Academic Search

This patent describes a vaporized liquid fuel combustion apparatus comprising: a cylinder defining a combustion chamber, the cylinder having an inlet end for receipt of combustion air, a first flange surrounding the inlet end and an outlet end for exhausting gaseous combustion products; means for introducing the fuel into the combustion chamber and ignition means exposed to the combustion chamber

Y. Kimijima; K. Kikuchi

1986-01-01

209

Vapor-liquid equilibria of hydrocarbons and fuel oxygenates. 2  

SciTech Connect

Vapor-liquid equilibrium data for methyl tert-butyl ether (MTBE) + 1-heptene, MTBE + four-component gasoline prototype, ethanol + four-component gasoline prototype, and separately MTBE and ethanol with the Auto/Oil Air Quality Improvement Research Gasoline Blend A are reported. Small additions of MTBE have a very small effect on the total equilibrium pressure of this gasoline blend, and at most temperatures will decrease this pressure. In contrast, small additions of ethanol to this gasoline blend result in a significant increase in the equilibrium pressure at all temperatures. Analysis shows that the vapor-liquid equilibrium data for the MTBE-containing systems are easily correlated using a modified Peng-Robinson equation of state with conventional van der Waals one-fluid mixing rules. Data for mixtures containing ethanol cannot be accurately correlated in this way.

Bennett, A.; Lamm, S.; Orbey, H.; Sandler, S.I. (Univ. of Delaware, Newark (United States))

1993-04-01

210

Vapor-liquid equilibria of hydrocarbons and fuel oxygenates. 2  

Microsoft Academic Search

Vapor-liquid equilibrium data for methyl tert-butyl ether (MTBE) + 1-heptene, MTBE + four-component gasoline prototype, ethanol + four-component gasoline prototype, and separately MTBE and ethanol with the Auto\\/Oil Air Quality Improvement Research Gasoline Blend A are reported. Small additions of MTBE have a very small effect on the total equilibrium pressure of this gasoline blend, and at most temperatures will

Alison Bennett; Stephan Lamm; Hasan Orbey; Stanley I. Sandler

1993-01-01

211

Prediction of mixture vapor–liquid equilibrium from the combined use of Peng–Robinson equation of state and COSMO-SAC activity coefficient model through the Wong–Sandler mixing rule  

Microsoft Academic Search

In this work we examined the prediction of vapor–liquid equilibria (VLE) of mixtures from the combined use of the Peng–Robinson equation of state (PR EOS) and the COSMO-SAC liquid activity coefficient model (LM). Based on the results of quantum mechanical calculations, it has been shown that the COSMO-SAC model is capable of predicting VLE of mixtures away from the critical

Ming-Tsung Lee; Shiang-Tai Lin

2007-01-01

212

Vapor-liquid equilibria for alcohol + alcohol + sodium iodide at 298.15 K  

Microsoft Academic Search

Estimation and correlation of phase equilibria data in chemical engineering are indispensable for the design of equilibrium separation processes. If a salt, being completely nonvolatile, is added to the solvent mixture, the relative volatility generally changes; this is known as the salting-in or -out effect on vapor-liquid equilibria. Vapor-liquid equilibria for methanol + propan-1-ol + NaI, methanol + propan-2-ol +

Hideki Yamamoto; Koji Fukase; Junji Shibata

1996-01-01

213

Isobaric (vapour + liquid) equilibrium for N-methyl-2-pyrrolidone with branched alcohols  

Microsoft Academic Search

The (vapour+liquid) equilibrium (VLE) and boiling temperature measurements have been determined at 95.3kPa as a function of composition for the binary liquid mixtures of N-methyl-2-pyrrolidone (NMP) with branched alcohols using a Swietoslawski-ebulliometer. The branched alcohols include 2-propanol, 2-butanol, 2-methyl-l- propanol, 2-methyl-2-propanol, and 3-methyl-l-butanol. The experimental temperature-composition (T–x) results were used to estimate Wilson parameters and then used to calculate the

P. Gnanakumari; P. Venkatesu; Cheng-Ting Hsieh; M. V. Prabhakara Rao; Ming-Jer Lee; Ho-mu Lin

2009-01-01

214

Vapor-Liquid Equilibria Using the Gibbs Energy and the Common Tangent Plane Criterion  

ERIC Educational Resources Information Center

|Phase thermodynamics is often perceived as a difficult subject with which many students never become fully comfortable. The Gibbsian geometrical framework can help students to gain a better understanding of phase equilibria. An exercise to interpret the vapor-liquid equilibrium of a binary azeotropic mixture, using the equilibrium condition based…

Olaya, Maria del Mar; Reyes-Labarta, Juan A.; Serrano, Maria Dolores; Marcilla, Antonio

2010-01-01

215

Vapor–Liquid Equilibria of Alternative Refrigerants by Molecular Dynamics Simulations  

Microsoft Academic Search

Alternative refrigerants HFC-152a (CHF2CH3), HFC-143a (CF3CH3), HFC-134a (CF3CH2F), and HCFC-142b (CF2ClCH3) are modeled as a dipolar two-center Lennard–Jones fluid. Potential parameters of the model are fitted to the critical temperature and vapor–liquid equilibrium data. The required vapor–liquid equilibrium data of the model fluid are computed by the Gibbs–Duhem integration for molecular elongations L=0.505 and 0.67, and dipole moments µ*2=0, 2,

M. Lísal; R. Budinský; V. Vacek; K. Aim

1999-01-01

216

Vapor-liquid-solid growth of <110> silicon nanowire arrays  

NASA Astrophysics Data System (ADS)

The epitaxial growth of <110> silicon nanowires on (110) Si substrates by the vapor-liquid-solid growth process was investigated using SiCl4 as the source gas. A high percentage of <110> nanowires was obtained at high temperatures and reduced SiCl4 partial pressures. Transmission electron microscopy characterization of the <110> Si nanowires revealed symmetric V-shaped {111} facets at the tip and large {111} facets on the sidewalls of the nanowires. The symmetric {111} tip faceting was explained as arising from low catalyst supersaturation during growth which is expected to occur given the near-equilibrium nature of the SiCl4 process. The predominance of {111} facets obtained under these conditions promotes the growth of <110> SiNWs.

Eichfeld, Sarah M.; Hainey, Mel F.; Shen, Haoting; Kendrick, Chito E.; Fucinato, Emily A.; Yim, Joanne; Black, Marcie R.; Redwing, Joan M.

2013-09-01

217

Design of a high-pressure ebulliometer, with vapor-liquid equilibrium results for the systems CHF2 Cl + CF3 CH3 and CF3 CH2 F + CH2F2  

NASA Astrophysics Data System (ADS)

We describe the design and operation of a new high-pressure metal ebulliometer which can operate at pressures to at least 3 MPa in the range 220 400 K. Infinite-dilution activity coefficients are presented for the system CHF2Cl + CF3-CH, at 275 K and for the system CF3-CH2F + CH2F2, at 260, 230, and 300 K. The Wilson activity coellicient model and a virial coefficient model are applied to these systems, and the phase equilibrium conditions are calculated. The results are shown to agree well with predicted and with published measured values. The excess enthalpy is calculated and compared with results from a Peng Robinson equation of state. Vapor densities on the dew curves are given.

Weber, L. A.; Silva, A. M.

1996-07-01

218

Vapor-liquid coexistence of the Stockmayer fluid in nonuniform external fields.  

PubMed

We investigate the structure and phase behavior of the Stockmayer fluid in the presence of nonuniform electric fields using molecular simulation. We find that an initially homogeneous vapor phase undergoes a local phase separation in a nonuniform field due to the combined effect of the field gradient and the fluid vapor-liquid equilibrium. This results in a high-density fluid condensing in the strong field region. The system polarization exhibits a strong field dependence due to the fluid condensation. PMID:23767508

Samin, Sela; Tsori, Yoav; Holm, Christian

2013-05-22

219

Critical properties and vapor-liquid equilibria of the binary system propane + neopentane  

SciTech Connect

Vapor-liquid equilibrium data extending to critical pressures are reported for five mixtures of propane with neopentane. The data in pressure, temperature, and density are correlated to high accuracy by the Leung-Griffiths model as modified by Moldover, Rainwater, and coworkers. In addition, a complete bibliography of similar experiments on binary mixtures from the laboratory of W.B.K. is presented. 91 references.

Hissong, D.W.; Kay, W.B. (Ohio State Univ., Columbus, OH (United States). Dept. of Chemical Engineering); Rainwater, J.C. (National Inst. of Standards and Technology, Boulder, CO (United States). Thermophysics Div.)

1993-10-01

220

Vapor-Liquid Equilibria for Some Concentrated Aqueous PolymerSolutions  

SciTech Connect

Vapor-liquid-equilibrium data were obtained for binary aqueous solutions of six water-soluble linear polymers in the range 70-95 C. A classical gravimetric sorption method was used to measure the amount of solvent absorbed as a function of vapor-phase water pressure. Polymers studied were polyvinylpyrrolidone, polyethyleneoxide, polyvinylalcohol, hydroxyethylcellulose, polyethylenimine, polymethylvinylether. The experimental data were reduced with Hino's lattice model that distinguished the interactions due to London dispersion forces and those due to hydrogen bonding.

Striolo, Alberto; Prausnitz, John M.

1999-07-01

221

Isothermal vapor-liquid equilibria for mixtures of methyl tert-butyl ether, methyl acetate, and ethyl acetate  

Microsoft Academic Search

A static apparatus was applied to measure isothermal vapor-liquid equilibrium (VLE) data for binary and ternary mixtures composed of methyl tert-butyl ether (MTBE), methyl acetate, and ethyl acetate at temperatures from 353 K to 373 K. Maximum pressure azeotropes were exhibited in the MTBE + methyl acetate system. All the binary data passed thermodynamic consistency tests. Data reduction was made

Ming-Jer Lee; Chien-Chih Hsiao; Ho-mu Lin

1997-01-01

222

Influence of bond flexibility on the vapor-liquid phase equilibria of water.  

PubMed

The authors performed Gibbs ensemble simulations on the vapor-liquid equilibrium of water to investigate the influence of incorporating intramolecular degrees of freedom in the simple point charge (SPC) water model. Results for vapor pressures, saturation densities, heats of vaporization, and the critical point for two different flexible models are compared with data for the corresponding rigid SPC and SPC/E models. They found that the introduction of internal vibrations, and also their parametrization, has an observable effect on the prediction of the vapor-liquid coexistence curve. The flexible SPC/Fw model, although optimized to describe bulk diffusion and dielectric constants at ambient conditions, gives the best prediction of saturation densities and the critical point of the examined models. PMID:17286493

Raabe, Gabriele; Sadus, Richard J

2007-01-28

223

Comparison of the AMBER, CHARMM, COMPASS, GROMOS, OPLS, TraPPE and UFF force fields for prediction of vapor–liquid coexistence curves and liquid densities  

Microsoft Academic Search

Monte Carlo simulations in the isobaric–isothermal and Gibbs ensembles are used to compute liquid densities and vapor–liquid coexistence curves for a series of small organic molecules for the AMBER-96, CHARMM22, COMPASS, GROMOS 43A1, OPLS-aa, TraPPE-UA, and UFF force fields. The simulation results are compared with experimental measurements to provide an assessment of the accuracy expected when using these force fields

Marcus G. Martin

2006-01-01

224

Vapor — Liquid equilibrium in the methanol — Water — Methyl methoxyacetate system  

Microsoft Academic Search

Methyl methoxyacetate (HI) is the starting material in one of the syntheses of pyridoxine (vitamin t~), and is obtained by the esterification of chloroacetic acid with methanol in the presence of calcium chloride. After the separation of the aqueous solution of calcium chloride, methyl chloroacetate is methoxylated by a methanolic solution of sodium methoxide [1]. This reaction yields a mixture,

M. M. Avrutskii; M. V. Balyakina; G. E. Boksha; N. K. Nazarova; T. G. Pavlenko; V. V. Zarutskii; V. I. Gunar

1978-01-01

225

Experimental isobaric vapour–liquid–liquid equilibrium data for the quaternary systems water (1)–ethanol (2)–acetone (3)– n-butyl acetate (4) and water (1)–ethanol (2)–acetone (3)–methyl ethyl ketone (4) and their partially miscible-constituent ternaries  

Microsoft Academic Search

Experimental vapour–liquid–liquid equilibrium data for the (type B) quaternary systems water (1)–ethanol (2)–acetone (3)–n-butyl acetate (4) and water (1)–ethanol (2)–acetone (3)–methyl ethyl ketone (4) were measured using a circulation equilibrium still employing vigorous mechanical mixing in the boiling chamber. The first quaternary system was measured isobarically at pressures of 760, 600 and 360mm Hg, and the other system measured isobarically

O. A. D. Younis; D. W. Pritchard; M. M. Anwar

2007-01-01

226

Vapor-liquid equilibria for solutions of dendritic polymers  

SciTech Connect

Vapor-liquid equilibrium data were obtained for dendritic polymer solutions using a classic isothermal gravimetric-sorption method; the amount of solvent absorbed by the dendrimer was measured at increasing solvent activity. The polymers were polyamidoamine (PAMAM) dendrimers of generations 1, 2, and 4 and benzyl ether dendrimers with different end groups (aromatic rings, dodecyl chains, methyl ester groups, perfluoroalkyl chains) of generations 2 to 6, and two series of benzyl ether linear polymers that are analogues of the dendrimers. Solvents were acetone, acetonitrile, chloroform, cyclohexane, methanol, n-pentane, n-propylamine, tetrahydrofuran, and toluene. The temperature range was 35 to 89 C. The amount of solvent absorbed by the dendrimers depends, sometimes strongly, on the kind of dendrimer end groups. The relation between solvent absorption and dendrimer generation number, or molecular weight, depends on the solvent-dendrimer system and on temperature. Solvent absorption in linear polymers is below that for corresponding dendrimers, all or in part owing to crystallinity in the linear polymers.

Mio, C.; Kiritsov, S.; Thio, Y.; Brafman, R.; Prausnitz, J. [Univ. of California, Berkeley, CA (United States). Chemical Engineering Dept.]|[Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.; Hawker, C.; Malmstroem, E.E. [IBM Almaden Research Center, San Jose, CA (United States). Center for Polymeric Interfaces and Macromolecular Assemblies

1998-07-01

227

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

228

Molecular dynamics simulation for vapor-liquid coexistence of water in nanocylinder  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulation was conducted in order to investigate the vapor-liquid coexistence of the water molecules in nanopore. In this research, the Lennard-Jones energy parameter between a water molecule and an atom of nanopore was optimized so as to model the contact angle between a water droplet and the carbon material in the fuel cell. The TIP4P/2005 as the model of a water molecule was used; this model produces well the vapor-liquid coexistence line. All of the systems were equilibrated by Nosé-Hoover thermostat. The electrostatic interaction between water molecules was calculated through smooth particle mesh Ewald method. First, we equilibrated a water plug in the single-wall atomistic nanocylinder as a model of nanopore in the fuel cell with radius 1.3nm. Water molecules burst from an interface of the water plug in equilibration. Then, the equilibrium densities both in dense and dilute region ware sampled over 1 ns. The vapor-liquid coexistence line, density profile, free energy profile will be presented in the session.

Mima, Toshiki; Kinefuchi, Ikuya; Yoshimoto, Yuta; Miyoshi, Nobuya; Fukushima, Akinori; Tokumasu, Takashi; Takagi, Shu; Matsumoto, Yoichiro

2013-03-01

229

Vapor-liquid equilibria of mixtures of propane and isomeric hexanes  

SciTech Connect

Vapor-liquid equilibrium data extending to critical pressures are reported for mixtures of propane with each of the hexane isomers, n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane. Dew-bubble curves for five different compositions are tabulated for each of the five mixtures. The data in pressure, temperature, and density are successfully correlated by the Leung-Griffiths model as modified by Moldover, Rainwater, and coworkers. The coexistence surfaces are all quite similar with only subtle differences due to the different shapes of the isomeric hexane molecules.

Chun, Sun Woong; Kay, W.B. (Ohio State Univ., Columbus, OH (United States). Dept. of Chemical Engineering); Rainwater, J.C. (National Inst. of Standards and Technology, Boulder, CO (United States). Thermophysics Div.)

1993-10-01

230

Measurement and prediction of vapor–liquid equilibria of ternary systems containing ionic liquids  

Microsoft Academic Search

For the first time vapor–liquid equilibrium (VLE) data for ternary systems containing ionic liquids are reported. The data were measured by means of a computer-operated static VLE apparatus at 353.15K with the ionic liquids 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [EMIM]+[(CF3SO2)2N]? and 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [BMIM]+[(CF3SO2)2N]? and acetone, 2-propanol and water. The experimental VLE data of the binary systems were correlated using the Wilson, NRTL

Michael Döker; Jürgen Gmehling

2005-01-01

231

The effect of sulfur on vapor liquid fractionation of metals in hydrothermal systems  

NASA Astrophysics Data System (ADS)

Despite the growing evidence that the vapor phase, formed through magma degassing and ore fluid boiling, can selectively concentrate and transport metals, the effects of major volatile components like sulfur, chlorine or carbon dioxide on the metal vapor-liquid fractionation and vapor-phase transport under magmatic-hydrothermal conditions remain poorly known. We performed systematic experiments to investigate the effect of sulfur ligands on metal vapor-liquid partitioning in model H 2O-S-NaCl-KCl-NaOH systems at temperatures from 350 to 500 °C. Results show that at acidic-to-neutral conditions, vapor-liquid equilibrium distribution coefficients, Km = mvapor / mliquid, where m is the mass concentration of the metal in corresponding phase, of metalloids (As, Sb) and base metals (Zn, Fe, Pb, Ag) are in the range 0.1-1.0 and 0.001-0.1, respectively, and are not significantly affected by the presence of geologically common sulfur concentrations, up to 1-3 wt.% S. In contrast, the partitioning of Cu, Au, and Pt into the vapor increases by a factor of 100 in comparison to the S-free water-salt system, yielding Km values of 0.5-1.0, 1-10, and 10-20, respectively, due to formation of volatile neutral complexes with H 2S and, possibly, SO 2. In neutral-to-basic systems, Zn, Pb, Fe and Ag show 10-100-fold increase of their partition coefficients, whereas Cu, Au and Pt exhibit Km values of up to several orders of magnitude lower, compared to acidic conditions at similar temperature, pressure and sulfur contents. These vapor-liquid distribution patterns result from combined effects of i) formation of volatile species with reduced sulfur ligands in the vapor phase, ii) changes in the metal speciation in the coexisting liquid phase as a function of pH, and iii) solute-solvent interactions in both phases. Our data explain the vapor-liquid fractionation trends for many metals as inferred in coexisting brine and vapor inclusions from magmatic-hydrothermal deposits, and provide a first experimental evidence for the dramatic increase of the mobility of Cu, Au and Pt in sulfur-enriched acidic magmatic-hydrothermal vapors, consistent with geological models of Au ± Cu ores formation and distribution in porphyry-epithermal settings.

Pokrovski, Gleb S.; Borisova, Anastassia Yu.; Harrichoury, Jean-Claude

2008-02-01

232

Vapor-liquid equilibria of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems  

Microsoft Academic Search

Vapor-liquid equilibrium data of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems were measured at 60, 160, 300, and 760 mmHg at temperatures ranging from 315 to 488 K. The apparatus used in this work is a modified still especially designed for the measurement of low-pressure VLE, in which both liquid and vapor are continuously recirculated.

S. Y. Mun; Huen Lee

1999-01-01

233

Effect of the line tension at the vapor-liquid-solid boundary on the growth of silicon nanocrystals  

Microsoft Academic Search

We examine the thermodynamic aspects of the effect of the line tension at a bent vapor-liquid-solid boundary on quasi-one-dimensional\\u000a growth of silicon nanowires. Experimental data demonstrate that there is a limiting size of solvent nanodrops below which\\u000a they cannot exist in equilibrium and that there is a limiting nanowire diameter starting at which the increase in line tension\\u000a with decreasing

V. A. Nebol’sin; A. I. Dunaev; M. A. Zavalishin

2008-01-01

234

Vapor-liquid equilibria for the difluoromethane (HFC-32) + 1,1,1-trifluoroethane (HFC-143a) system  

SciTech Connect

Isothermal vapor-liquid equilibrium data of the binary system of difluoromethane (HFC-32) + 1,1,1-trifluoroethane (HFC-143a) were obtained in the temperature range from 263.15 K to 313.15 K. Temperature, pressure, and compositions of the liquid and vapor phases were measured with a circulation type apparatus. The experimental data were correlated with the Canahan-Starling-De Santis, Peng-Robinson, and Redlich-Kwong-Soave equations of state.

Kim, C.N.; Park, Y.M.

2000-02-01

235

A field-space conformal-solution method: Binary vapor-liquid phase behavior  

NASA Astrophysics Data System (ADS)

The field-space conformal solution method provides an entirely new thermodynamic framework for the description of fluid mixtures in terms of the properties of a pure reference fluid. The utility and performance of the method are examined in the special case of vapor-liquid equilibrium correlation for simple mixtures. This is one of several cases in which field-space methods have numerical or theoretical advantages over methods presently used in mixture property correlation; only properties along the vapor pressure curve of the purefluid reference system are required for a complete description of the mixture phase behavior. Vapor-liquid equilibrium data for three binary hydrocarbon mixtures, n-butane + n-pentane, n-butane + n-hexane, and n-butane + n-octane, are correlated with a simple implementation of the method having two independent mixture parameters. Two pure-fluid equations of state, a Peng-Robinson equation and a 32-constant modified Benedict-Webb-Rubin equation, are tested as reference systems. The effects of differences in the quality of the reference system and of a range of mixture component size ratios are examined.

Storvick, T. S.; Fox, J. R.

1990-01-01

236

Thermomigration of Biphase Vapor-Liquid Droplets in Solids.  

National Technical Information Service (NTIS)

The thermomigration of biphase vapor-liquid droplets was studied in KCl as a function of droplet size and the relative proportions of gas and liquid phases in the droplets. Droplets containing more than 10 vol. % of gas migrated down thermal gradients tow...

H. E. Cline T. R. Anthony

1971-01-01

237

Prediction of salt effect on vapor–liquid equilibria  

Microsoft Academic Search

In this paper, a newly proposed model based on solvation between pure solvent and salt for prediction of salt effect on vapor–liquid equilibria is presented by using only the vapor pressure depression data of pure solvent+salt systems that compose the mixed solvent with salt system. The proposed model predicts thermodynamically the salt effect by solvation number between each pure solvent

Shuzo Ohe

1998-01-01

238

Ebulliometric measurement of vapor-liquid equilibria for four binary systems; methanol + silicon tetramethoxide, methanol + silicon tetraethoxide, ethanol + silicon tetramethoxide, and ethanol + silicon tetraethoxide  

Microsoft Academic Search

The authors discuss vapor pressures of silicon tetramethoxide and silicon tetraethoxide measured with a small ebulliometer. Boiling points for the four binary systems made of alcohol (methanol and ethanol) and alkoxide (silicon tetramethoxide and silicon tetraethoxide) were further measured at 760 and 450 mmHg pressures, and their vapor-liquid equilibrium relations were determined by using the Wilson equation.

Masahiro Kato; Hiroyuki Tanaka

1989-01-01

239

Vapor + liquid equilibria for the ternary system methane + ethane + carbon dioxide at 230 K and its constituent binaries at temperatures from 207 to 270 K  

SciTech Connect

Vapor-liquid equilibrium data for the binary system methane + carbon dioxide were measured at 230, 250, and 270 K. The ethane + carbon dioxide system was studied at 207, 210, 213, 230, 250, and 270 K, and the methane + ethane system was studied at 210, 230, 250, and 270 K. Ternary vapor-liquid equilibria for the methane + ethane + carbon dioxide system were measured at 230 K over the pressure range from 1.15 to 6.59 MPa. The Peng-Robinson equation of state was used to model the systems, and binary interaction coefficients are reported.

Wei, M.S.W. [CER Corp., Henderson, NV (United States); Brown, T.S. [Conoco Inc., Ponca City, OK (United States); Kidnay, A.J.; Sloan, E.D. [Colorado School of Mines, Golden, CO (United States). Dept. of Chemical Engineering

1995-07-01

240

Vapor-liquid equilibria for alcohol + alcohol + sodium iodide at 298.15 K  

SciTech Connect

Estimation and correlation of phase equilibria data in chemical engineering are indispensable for the design of equilibrium separation processes. If a salt, being completely nonvolatile, is added to the solvent mixture, the relative volatility generally changes; this is known as the salting-in or -out effect on vapor-liquid equilibria. Vapor-liquid equilibria for methanol + propan-1-ol + NaI, methanol + propan-2-ol + NaI, ethanol + propan-1-ol + NaI, and ethanol + propan-2-ol + NaI systems were measured at 298.15 K using a static method. The apparatus was tested by comparing results for ethanol + water and ethanol + water + CaCl{sub 2} with literature results. Results were tested for thermodynamic consistency by Herinton`s area test and point test. NaI exerted a salting-in effect on all binary alcohol solutions and the order of the salt effect of NaI was methanol + ethanol < ethanol + propan-1-ol < ethanol + propan-2-ol < methanol + propan-1-ol < methanol + propan-2-ol. Hala`s model was applied for the correlation of four alcohol + alcohol + salt systems using observed data. Calculated {beta} values in Hala`s equation were between 2.8 and 3.9 for the four alcohol + alcohol + NaI systems.

Yamamoto, H.; Fukase, K.; Shibata, J. [Kansai Univ., Suita, Osaka (Japan)

1996-09-01

241

Vapor-liquid equilibria in the carbon dioxide + 1-propanol system  

SciTech Connect

High-pressure vapor-liquid equilibrium measurements of CO{sub 2} + alkanol systems are of interest due to their importance in the supercritical extraction of thermally labile compounds, dehydration of alcohols using supercritical carbon dioxide, and extraction of natural products using near critical solvents. Vapor-liquid equilibria for CO{sub 2} + 1-propanol mixtures have been measured at 315.0, 326.5, and 337. K using a high-pressure flow apparatus. The pressure in the experiments varied from 26.38 to 89.7 MPa. Data at 315.0 K were found to be significantly different from the data reported by Suzuki et and Yao et al. However, the results at 337.2 K are in good agreement with the results of Suzuki et al and the data appear to be more consistent with the trends exhibited by other CO{sub 2} + 1-alkanol mixture The data were correlated with Patel-Teja and Peng-Robinson equations of state using classical van de Waals one-fluid mixing rules and with the Peng-Robinson-Stryjek-Vera equation of state using the Wong-Sandler mixing rules.

Vandana, V.; Teja, A.S. [Georgia Inst. of Technology, Atlanta, GA (United States). School of Chemical Engineering

1995-03-01

242

Toward a Monte Carlo program for simulating vapor-liquid phase equilibria from first principles  

SciTech Connect

Efficient Monte Carlo algorithms are combined with the Quickstep energy routines of CP2K to develop a program that allows for Monte Carlo simulations in the canonical, isobaric-isothermal, and Gibbs ensembles using a first principles description of the physical system. Configurational-bias Monte Carlo techniques and pre-biasing using an inexpensive approximate potential are employed to increase the sampling efficiency and to reduce the frequency of expensive ab initio energy evaluations. The new Monte Carlo program has been validated through extensive comparison with molecular dynamics simulations using the programs CPMD and CP2K. Preliminary results for the vapor-liquid coexistence properties (T = 473 K) of water using the Becke-Lee-Yang-Parr exchange and correlation energy functionals, a triple-zeta valence basis set augmented with two sets of d-type or p-type polarization functions, and Goedecker-Teter-Hutter pseudopotentials are presented. The preliminary results indicate that this description of water leads to an underestimation of the saturated liquid density and heat of vaporization and, correspondingly, an overestimation of the saturated vapor pressure.

McGrath, M; Siepmann, J I; Kuo, I W; Mundy, C J; Vandevondele, J; Sprik, M; Hutter, J; Mohamed, F; Krack, M; Parrinello, M

2004-10-20

243

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

244

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

245

Phase Equilibrium Studies.  

National Technical Information Service (NTIS)

A phase equilibrium model has been developed for the SRC-I process, as well as the other coal liquefaction processes. It is applicable to both vapor/liquid and liquid/liquid equilibria; it also provides an approximate but adequate description of aqueous m...

P. M. Mathias F. P. Stein

1983-01-01

246

Vapor-liquid equilibria for dendritic-polymer solutions  

SciTech Connect

Vapor-liquid equilibria for dendritic-polymer solutions were obtained using a classic gravimetric-sorption method; the amount of solvent absorbed by the dendrimer was measured as a function of solvent vapor pressure. Three series of dendrimers, each with the same tertiary amine core structure, but different surface groups, were investigated in a variety of organic solvents in the range 50--75 C. The dendrimer surface groups were dodecylamines, octadecyl amides, and polyisobutylene. Solvent absorption depends strongly on dendrimer composition and generation number.

Lieu, J.G.; Liu, M.; Frechet, J.M.J. [Univ. of California, Berkeley, CA (United States); Prausnitz, J.M. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering]|[Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.

1999-05-01

247

Numerical analysis of vapor-liquid two-phase system based on the Enskog-Vlasov equation  

NASA Astrophysics Data System (ADS)

In this study, equilibrium and nonequilibrium numerical simulations for vapor-liquid two-phase systems were performed by using the Enskog-Vlasov equation. The kinetic boundary condition (KBC) at the interface was investigated. The simulation results showed that at a low or slightly high liquid temperature, the velocity distribution of the KBC obtained by our simulation is anisotropic Gaussian; this result agrees qualitatively with the results of the MD simulation performed by Ishiyama et al. (PRL, 2005). Also, the nonequilibrium nature of KBC becomes larger with the increase of liquid temperature.

Kobayashi, Kazumichi; Ohashi, Kotaro; Watanabe, Masao

2012-11-01

248

Vapor-liquid equilibria for the difluoromethane (HFC-32) + 1,1,1,2-tetrafluoroethane (HFC-134a) system  

SciTech Connect

Isothermal vapor-liquid equilibrium data of the binary mixture of difluoromethane (HFC-32) + 1,1,1,2-tetrafluoroethane (HFC-134a) have been measured in the temperature range between 263 K and 323 K. The experiment was carried out with a circulation type apparatus with the measurement of temperature, pressure, and compositions of the liquid and vapor phases. The experimental data were correlated with the Peng-Robinson and Redlich-Kwong-Soave equations of state, and comparison with literature results has been made.

Chung, E.Y.; Kim, M.S. [Seoul National Univ. (Korea, Republic of). Dept. of Mechanical Engineering

1997-11-01

249

Vapor-liquid equilibria in the systems of toluene/aniline, aniline/naphthalene, and naphthalene/quinoline  

SciTech Connect

This paper reports on vapor-liquid equilibria for the aniline/naphthalene, toluene/aniline, and naphthalene/quinoline systems that have been determined at 0-1500 kPa and 490-623 K by using a static equilibrium cell. The data can be accurately correlated with the modified Peng-Robinson equation of state by using density-dependent mixing rules. The binary interaction parameters and correction factors for the equation of state are reported at each isotherm. The presence of coal-derived solids in these binary systems did not influence any of the binary bubble pressures.

Lee, C.H.; Mohamed, R.S.; Holder, G.D. (Chemical And Petroleum Engineering Dept., Univ. of Pittsburgh, Pittsburgh, PA (US))

1992-04-01

250

Isobaric Spin in Nuclear Physics.  

National Technical Information Service (NTIS)

A review is given of the state of isobaric spin studies in low energy physics. Topics include: isobaric spin quantum numbers; charge independance; isobaric spin impurities; selection rules for extranuclear reactions (beta decay, radiative transitions), di...

D. Robson

1966-01-01

251

Equilibrium  

NSDL National Science Digital Library

Using a visual approach, this applet is designed to help students learn to solve equilibrium calculations and also to help them gain a deeper understanding of the topic. It can be used by the instructor in the classroom as equilibrium topics are introduced. Sample exercises for students are included. The text is available in both English and Spanish.

252

Isobaric multiplet width equation.  

National Technical Information Service (NTIS)

The isobaric multiplet width equation is verified in the light of recent experimental information on masses and widths. The verification is carried out for the known level widths and the results came in support of the isobaric width equation removing all ...

A. M. Awin

1991-01-01

253

Effect of 1,2-propanediol on the vapor-liquid equilibria of the ethyl acetate + ethanol system at 101.3 kPa  

Microsoft Academic Search

Vapor-liquid equilibrium (VLE) data for the system ethyl acetate + ethanol in the presence of 1,2-propanediol at concentrations of 0%, 20%, 30%, and 40% by weight were measured at 101.3 kPa. The experimental VLE data of the ternary system ethyl acetate + ethanol + 1,2-propanediol were correlated by the Margules, Wilson, NRTL, and UNIQUAC liquid models. The relative volativities of

Chein-Hsiun Tu; Yuh-Shen Wu; Feng-Chao Ou

1997-01-01

254

Isothermal vapor-liquid equilibria for 1,1,1,2-tetrafluoroethane + propane and propane + 1,1,1,-trifluoroethane at 283.18 K  

Microsoft Academic Search

Isothermal vapor-liquid equilibria (VLE) for the binary systems 1,1,1,2-tetrafluoroethane (R134a) + propane (R290) and propane + 1,1,1-trifluoroethane (R143a) were measured at 283.18 K using a recirculation apparatus in which the vapor phase was forced through the liquid. The phase composition at equilibrium was measured by gas chromatography, calibrating its response using gravimetrically prepared mixtures. The data were correlated using the

Roman Stryjek; Sergio Bobbo; Roberto Camporese

1998-01-01

255

Vapor–liquid equilibria of the (hexafluoroethane + 1,1,1-trifluoroethane) binary system from 258 to 343 K up to 3.89 MPa  

Microsoft Academic Search

Development of modern refrigeration systems is critical for the success of new global environmental protection efforts. The binary system of refrigerants: Hexafluoroethane (R116)+1,1,1-trifluoroethane (R143a), has been studied with the aim of providing PTxy data. Isothermal vapor–liquid equilibrium data have been generated using the “static–analytic” method from 258 to 328K at pressures from 0.39 to 3.89MPa. The model composed of the

Hakim Madani; Alain Valtz; Christophe Coquelet; Abdeslam Hassen Meniai; Dominique Richon

2009-01-01

256

Vapor–liquid equilibria of propionic acid–water system in the presence of different types of inorganic salts: effect of temperature and salt concentration  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium data at 40 and 50°C were obtained by using a headspace gas chromatography (GC) (one of the static methods) for the propionic acid–water system in the presence and absence of chloride salts. Propionic acid was salted-out in the presence of any chloride salt, in the following order: aluminum chloride>calcium chloride>sodium chloride>ammonium chloride. The effects of AlCl3, CaCl2,

Fawzi Banat; Sameer Al-Asheh; Jana Simandl

2003-01-01

257

APPLICATION OF THE SCLC MODEL TO THE SALT EFFECT IN VAPOR-LIQUID EQUILIBRIA  

Microsoft Academic Search

The ability of the rationalized SCLC model to correlate data on the salt effect in vapor-liquid equilibria is examined in this work. For a system consisting of two miscible solvents the effect of salt in altering the relative volatility is represented by the model with four adjustable binary interaction parameters. The model is shown to correlate vapor-liquid equilibria of several

K. V. NARAYANAN; M. S. ANANTH

1995-01-01

258

Modified solvation model for salt effect on vapor–liquid equilibria  

Microsoft Academic Search

The prediction method had been presented for salt effect on vapor–liquid equilibria by solvation model. This model assumes that salt effect is caused by solvation and solvated solvent molecular cannot contribute to vapor–liquid equilibria. The model took into account the vapor pressure depression in mixed solvent. In this work, the solvation model was modified. The relation between solvation number in

Hideaki Takamatsu; Shuzo Ohe

2002-01-01

259

New Exciplex Fluorescence System for Vapor-Liquid Visualization  

NASA Astrophysics Data System (ADS)

We report a new and viable diagnostic chemical systems for two phase vapor-liquid visualization based on exciplex (excited state complex) formed between N,N-dimethylaniline (DMA) and 1,4,6- trimethylnaphthalene (1,4,6-TMN) in isooctane.( J. U. Kim et al., ``Exciplex Fluorescence Visualization Systems for Pre-Combustion Diagnosis of an Automotive Gasoline Engine'', SAE paper 960826, 1996 ) Steady-state and time-resolved emission spectroscopies were used in order to study the exciplex kinetics. Temperature dependent measurements of the exciplex fluorescence reveal that the quenching mechanism associated with the exciplex is sufficiently favorable to permit the exciplex to exist at temperatures approaching 150^circ C. This system is designed to probe the spatial and temporal evolution of fuel mixture formation in a spark ignition engine by use of spectrally well-separated fluorescence images obtained from the monomer and exciplex constituents dissolved in gasoline fuel.

Kim, J. U.; Darrow, Jon; Nocera, D. G.; Schock, H. J.; Golding, B.

1997-03-01

260

Vapor-liquid equilibria for the binary systems of benzene/toluene, diphenylmethane/toluene, m-cresol/1,2,3,4-tetrahydronaphthalene, and quinoline/benzene  

SciTech Connect

Vapor-liquid equilibrium (VLE) data for the binary systems of benzene/toluene, diphenylmethane/toluene, m-cresol/1,2,3,4-tetrahydronaphthalene, and benzene/quinoline were measured at low to moderate pressures (0-1733 kPa) by using a static equilibrium cell. The data were isothermally correlated by using the Peng-Robinson equation of state to describe both vapor and liquid phases. The data were also correlated by using the Peng-Robinson equation of state to describe the vapor phase and the universal quasi-chemical (UNIQUAC) excess Gibbs free energy expression for the liquid phase.

Klara, S.M.; Mohamed, R.S.; Dempsey, D.M.; Holder, G.D.

1987-04-01

261

Vapor-liquid equilibria in the systems of n-decane/tetralin, n-hexadecane/tetralin, n-decan/1-methylnaphthalene, and 1-methylnaphthalene/tetralin  

SciTech Connect

Vapor-liquid equilibrium data for the binary systems of n-decane/tetralin, n-hexadecane/tetralin, n-decane/1-methyinaphthalene, and 1-methyinaphthalene/tetralin were measured at a low to moderate pressure (0 - 1123 kPa) by using a static equilibrium cell. The binary P-x data were isothermally correlated using the modified Peng-Robinson equation of state to describe both vapor and liquid phases at 473.15, 533.15, and 573.15 K. In this paper interaction parameters for density-dependent mixing rules are reported at each isotherm.

Lee, C.H.; Dempsey, D.M.; Mohamed, R.S.; Holder, G.D. (Chemical and Petroleum Engineering Dept., Univ. of Pittsburgh, Pittsburgh, PA (US))

1992-04-01

262

Design of a high-pressure ebulliometer, with vapor-liquid equilibrium results for the systems CHF{sub 2}Cl + CF{sub 3}-CH{sub 3} and CF{sub 3}-CH{sub 2} F+CH{sub 2}F{sub 2}  

SciTech Connect

The authors describe the design and operation of a new high-pressure metal ebulliometer which can operate at pressures to at least 3 MPa in the range 220-400 K. Infinite-dilution activity coefficients are presented for the system CHF{sub 2}Cl + CF{sub 3}-CH{sub 3} at 275 K and for the system CF{sub 3}-CH{sub 2}F + CH{sub 2}F{sub 2} at 260, 280, and 300 K. The Wilson activity coefficient model and a virial coefficient model are applied to these systems, and the phase equilibrium conditions are calculated. The results are shown to agree well with predicted and with published measured values. The excess enthalpy is calculated and compared with results from a Peng-Robinson equation of state. Vapor densities on the dew curves are given.

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

1996-07-01

263

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

264

Vapor-liquid equilibria of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems  

SciTech Connect

Vapor-liquid equilibrium data of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems were measured at 60, 160, 300, and 760 mmHg at temperatures ranging from 315 to 488 K. The apparatus used in this work is a modified still especially designed for the measurement of low-pressure VLE, in which both liquid and vapor are continuously recirculated. For the analysis of salt-containing solutions, a method incorporating refractometry and gravimetry was used. From the experimental measurements, the effect of lithium bromide on the VLE behavior of water + 1,3-propanediol was investigated. The experimental data of the salt-free system were successfully correlated using the Wilson, NRTL, and UNIQUAC models. In addition, the extended UNIQUAC model of Sander et al. was applied to the VLE calculation of salt-containing mixtures.

Mun, S.Y.; Lee, H.

1999-12-01

265

Vapor-liquid equilibria of binary mixtures of alkanols with alkanes from atmospheric pressure to the critical point  

NASA Astrophysics Data System (ADS)

A reformulated version of the Wong-Sandler mixing rule and the Peng-Robinson equation of state are used for the correlation and prediction of the vapor-liquid equilibrium of several alkanol + alkane binary systems. The description of these mixtures provides a stringent test since cubic equations of state with conventional mixing rules usually predict false liquid-liquid splits for such systems. For all systems, the model parameters used were fit to data on the lowest-temperature isotherm and then higher-temperature isotherms were successfully predicted with those parameters. False phase splitting was avoided by using a constrained parameter fit. For highly asymmetric (in size) alkanol+alkane binaries four parameters were necessary for an accurate representation of the data, while for less asymmetric alkanol + alkane binaries only two parameters were used.

Orbey, H.; Sandier, S. I.

1995-05-01

266

Vapor-liquid equilibria of binary mixtures of alkanols with alkanes from atmospheric pressure to the critical point  

SciTech Connect

A reformulated version of the Wong-Sandler mixing rule and the Peng-Robinson equation of state are used for the correlation and prediction of the vapor-liquid equilibrium of several alkanol + alkane binary systems. The description of these mixtures provides a stringent test since cubic equations of state with conventional mixing rules usually predict false liquid-liquid splits for such systems. For all systems, the model parameters used were fit to data on the lowest-temperature isotherm and then higher-temperature isotherms were successfully predicted with those parameters. False phase splitting was avoided by using a constrained parameter fit. For highly asymmetric (in size) alkanol + alkane binaries four parameters were necessary for an accurate representation of the data, while for less asymmetric alkanol + alkane binaries only two parameters were used.

Orbey, H. [Middle East Technical Univ., Ankara (Turkey); Sandler, S.I. [Univ. of Delaware, Newark, DE (United States)

1995-05-01

267

Isobaric groundwater well  

Microsoft Academic Search

A method is described for measuring a parameter in a well, under isobaric conditions, including such parameters as hydraulic gradient, pressure, water level, soil moisture content and\\/or aquifer properties. The method as presented comprises providing a casing having first and second opposite ends, and a length between the ends, the casing supporting a transducer having a reference port; placing the

J. M. Hubbell; J. B. Sisson

1999-01-01

268

Isobaric groundwater well  

Microsoft Academic Search

A method of measuring a parameter in a well, under isobaric conditions, including such parameters as hydraulic gradient, pressure, water level, soil moisture content and\\/or aquifer properties the method as presented comprising providing a casing having first and second opposite ends, and a length between the ends, the casing supporting a transducer having a reference port; placing the casing lengthwise

Joel M. Hubbell; James B. Sisson

1999-01-01

269

Turbulence and heat exchange in condensing vapor-liquid flow  

NASA Astrophysics Data System (ADS)

Turbulence and heat exchange during condensation of a vapor stream countercurrently flowing to a subcooled liquid stream in a slightly inclined channel has been investigated by direct numerical simulation (DNS). Condensation rates and imposed pressure gradients have been varied, and capillary-gravity waves have been allowed to develop at the (deformable) vapor-liquid interface. These simulations extend our previous DNS of turbulence and scalar exchange in stratified gas-liquid flows without condensation. The previous studies indicated that for conditions in which the gas-liquid interface remained continuous, i.e., did not ``break,'' scalar exchange rates on both the gas and liquid sides were largely determined by sweeps which brought high momentum fluid from the bulk flow to the interface. As sweep frequencies were found to scale with interfacial friction velocities, scalar exchange coefficients could be parametrized with a surface renewal theory. The issue addressed in the current work is how these findings are altered by condensation which acts somewhat like suction through a wall on the vapor side and injection through a wall on the liquid side. Both suction and injection have been found to affect shear stresses, turbulence characteristics, and scalar exchange rates, and hence similar effects might be expected during condensation. The present simulations indicate that the turbulence characteristics in both phases are affected, with turbulence intensities and Reynolds stresses being enhanced on the vapor side and attenuated on the liquid side. For a given imposed pressure gradient, the interfacial shear stress decreases as a result of the interfacial momentum exchange due to condensation. Interfacial waves are also found to be damped by condensation and the streamwise vortical structures on the liquid side are attenuated. The frequencies of sweeps and ejections, however, do scale with the interfacial friction velocity, reduced due to condensation, as does the liquid-side heat transfer coefficient. The simulations indicate that the scaling relationship between the interfacial friction velocity and the liquid-side heat transfer coefficient is similar to that in the absence of condensation, although the interfacial friction velocity itself is different, being dependent on condensation rates. As condensation rates depend in turn on the liquid-side heat transfer, their prediction becomes a coupled problem. A procedure for determining condensation rates as a function of imposed pressure gradient and liquid subcooling is derived from the simulations.

Lakehal, Djamel; Fulgosi, Marco; Banerjee, Sanjoy; Yadigaroglu, George

2008-06-01

270

Coal Gasification Pilot Plant Support Studies. Subtask 3-2. Phase Equilibrium Studies as Applied to Treatment of Raw Bases from Coal Gasification.  

National Technical Information Service (NTIS)

Several methods to predict the phase equilibrium behavior of gas mixtures at different temperatures and pressures appear in the literature. In this study, four of these correlations have been evaluated using experimentally derived vapor-liquid equilibrium...

1980-01-01

271

Vapor-liquid phase coexistence and transport properties of two-dimensional oligomers.  

PubMed

Grand-canonical transition-matrix Monte Carlo and histogram reweighting techniques are used herein to study the vapor-liquid coexistence properties of two-dimensional (2D) flexible oligomers with varying chain lengths (m = 1-8). The phase diagrams of the various 2D oligomers follow the correspondence state (CS) principle, akin to the behavior observed for bulk oligomers. The 2D critical density is not influenced by the oligomer chain length, which contrasts with the observation for the bulk oligomers. Line tension, calculated using Binder's formalism, in the reduced plot is found to be independent of chain length in contrast to the 3D behavior. The dynamical properties of 2D fluids are evaluated using molecular dynamics simulations, and the velocity and pressure autocorrelation functions are investigated using Green-Kubo (GK) relations to yield the diffusion and viscosity. The viscosity determined from 2D non-equilibrium molecular dynamics simulation is compared with the viscosity estimated from the GK relations. The GK relations prove to be reliable and efficient for the calculation of 2D transport properties. Normal diffusive regions are identified in dense oligomeric fluid systems. The influence of molecular size on the diffusivity and viscosity is found to be diminished at specific CS points for the 2D oligomers considered herein. In contrast, the viscosity and diffusion of the 3D bulk fluid, at a reduced temperature and density, are strongly dependent on the molecular size at the same CS points. Furthermore, the viscosity increases and the diffusion decreases multifold in the 2D system relative to those in the 3D system, at the CS points. PMID:22938253

Patra, Tarak K; Hens, Abhiram; Singh, Jayant K

2012-08-28

272

On the isobaric thermal expansivity of liquids  

NASA Astrophysics Data System (ADS)

The temperature and pressure dependence of isobaric thermal expansivity, ?p, in liquids is discussed in this paper. Reported literature data allow general trends in this property that are consistent with experimental evidence to be established. Thus, a negative pressure dependence is to be expected except around the critical point. On the other hand, ?p exhibits broad regions of negative and positive temperature dependence in the (T, p) plane depending on the nature of the particular liquid. These trends are rationalized here in terms of various molecular-based equations of state. The analysis of the Lennard-Jones, hard sphere square well and restricted primitive model equations allows understanding the differences in the ?p behavior between liquids of diverse chemical nature (polar, nonpolar, and ionic): broader regions of negative temperature and positive pressure dependencies are obtained for liquids characterized by larger ranges of the interparticle potential. Also, using the statistical associating fluid theory (SAFT) allowed the behavior of more complex systems (basically, those potentially involving chain and association effects) to be described. The effect of chain length is rather simple: increasing it is apparently equivalent to raise the interaction range. By contrast, association presents a quite complex effect on ?p, which comes from a balance between the dispersive and associative parts of the interaction potential. Thus, if SAFT parameters are adjusted to obtain low association ability, ?p is affected by each mechanism at clearly separate regions, one at low temperature, due to association, and the other to dispersive forces, which has its origin in fluctuations related with vapor-liquid transition.

Troncoso, Jacobo; Navia, Paloma; Romaní, Luis; Bessieres, David; Lafitte, Thomas

2011-03-01

273

On the isobaric thermal expansivity of liquids.  

PubMed

The temperature and pressure dependence of isobaric thermal expansivity, ?(p), in liquids is discussed in this paper. Reported literature data allow general trends in this property that are consistent with experimental evidence to be established. Thus, a negative pressure dependence is to be expected except around the critical point. On the other hand, ?(p) exhibits broad regions of negative and positive temperature dependence in the (T, p) plane depending on the nature of the particular liquid. These trends are rationalized here in terms of various molecular-based equations of state. The analysis of the Lennard-Jones, hard sphere square well and restricted primitive model equations allows understanding the differences in the ?(p) behavior between liquids of diverse chemical nature (polar, nonpolar, and ionic): broader regions of negative temperature and positive pressure dependencies are obtained for liquids characterized by larger ranges of the interparticle potential. Also, using the statistical associating fluid theory (SAFT) allowed the behavior of more complex systems (basically, those potentially involving chain and association effects) to be described. The effect of chain length is rather simple: increasing it is apparently equivalent to raise the interaction range. By contrast, association presents a quite complex effect on ?(p), which comes from a balance between the dispersive and associative parts of the interaction potential. Thus, if SAFT parameters are adjusted to obtain low association ability, ?(p) is affected by each mechanism at clearly separate regions, one at low temperature, due to association, and the other to dispersive forces, which has its origin in fluctuations related with vapor-liquid transition. PMID:21384980

Troncoso, Jacobo; Navia, Paloma; Romaní, Luis; Bessieres, David; Lafitte, Thomas

2011-03-01

274

Vapor-liquid equilibria for systems of 1-butanol with 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol at 30 and 100 kPa  

Microsoft Academic Search

Vapor-liquid equilibrium data were measured for binary systems of 1-butanol with 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol at 30 and 100 kPa. The experimental data obtained in this work are thermodynamically consistent according to a point-to-point consistency test, and deviation from ideal behavior is small in all cases. They can be equally well correlated with the Margules, Van Laar, Wilson, NRTL,

A. Aucejo; M. C. Burguet; J. B. Monton; R. Munoz; M. Sanchotello; M. I. Vazquez

1994-01-01

275

Isothermal vapor-liquid equilibria for the binary system 1,1,1-trifluoroethane (R143a) + 1,1,1,3,3,3-hexafluoropropane (R236fa) at 283.11, 298.16, and 313.21 K  

Microsoft Academic Search

A recirculation apparatus in which the vapor phase was forced through the liquid was used to measure isothermal vapor-liquid equilibria (VLE) for the binary system 1,1,1-trifluoroethane (R143a) + 1,1,1,3,3,3,-hexafluoropropane (R236fa) at 283.11, 298.16, and 313.21 K. The phase composition at equilibrium was measured with a gas chromatograph that was calibrated with gravimetrically prepared mixtures. The system shows a small deviation

Sergio Bobbo; Roberto Camporese; Claudio Zilio

2000-01-01

276

Vapor–liquid equilibria in the ternary system isobutyl alcohol + isobutyl acetate + butyl propionate and the binary systems isobutyl alcohol + butyl propionate, isobutyl acetate + butyl propionate at 101.3 kPa  

Microsoft Academic Search

Consistent vapor–liquid equilibrium (VLE) data at 101.3kPa have been determined for the ternary system isobutyl alcohol (IBA)+isobutyl acetate (IBAc)+butyl propionate (BUP) and two constituent binary systems: IBA+BUP and IBAc+BUP. The IBA+BUP system show lightly positive deviation from Raoult's law and IBAc+BUP system exhibits no deviation from ideal behaviour. The activity coefficients of the solutions were correlated with its composition by

R. Muñoz; J. B. Montón; M. C. Burguet; J. de la Torre

2005-01-01

277

VAPOR-LIQUID EQUILIBRIA IN THE TRIETHYLBORANE-DIBORANE SYSTEM  

Microsoft Academic Search

The pressure-composition isotherms at --25, 0, and 25 deg C are ; determined for the equilibrium vapor and liquid in the triethylborane -- diborame ; system. The pressure range covered is from 0 to 20 atmospheres (0 to 300 psia.). ; The results are presented in graphic form, and the compositions are expressed in ; terms of ethylene and diborane.

M. J. Montjar; J. W. Reed; J. D. Mulik; J. F. Masi; M. G. ed. Haddaway

1957-01-01

278

Choice of basis mixtures for the prediction of vapor-liquid equilibria using the UNIFAC model  

SciTech Connect

A link was established between the accurate prediction of vapor-liquid equilibria and azeotropes using the UNIFAC group model and the choice of the basis information. The component activity coefficients are plotted as functions of composition for all the sets of data in each binary system. The activity coefficients at infinite dilution are determined as graphical extrapolations of these plots. The plot for the butanol-hydrocarbon system is shown. It is shown that azeotrope parameters can be used as the basis information to predict vapor-liquid equilibria for several sets of systems.

Kushner, T.M.; Fainburg, G.D.; Vitman, T.A.; Serafimov, L.A.

1988-07-01

279

Vapor-liquid equilibria of alternative refrigerants and their binaries by molecular simulations  

Microsoft Academic Search

Alternative refrigerants HFC125 (CHF2CF3), HFC 134a (CF3CH2F) are modeled as a dipolar two-center Lennard-Jones fluid and alternative refrigerant HFC32 (CH2F2) is modeled as a dipolar Lennard-Jones fluid. We calculate vapor- liquid equilibria of these refrigerants by Gibbs -Duhem integration and vapor- liquid equilibria of two binaries (HFC 125+HFC 134a, and HFC 134a+HFC 32) by the reaction Gibbs ensemble Monte Carlo

R. Budinsky; V. Vacek; M. Lisal

280

Vapor-liquid phase equilibrium in systems with multiple chemical reactions  

Microsoft Academic Search

We introduce a new set of composition variables for treating phase equilibria in multicomponent, multi-reaction systems with or without inert components present. These variables provide a way of reducing the dimensionality of the problem and simplifying the analysis. We find that reactive azeotropes occur at points of equal transformed composition in each phase, but not equal mole fraction. Therefore, phase

Sophie Ung; Michael F. Doherty

1995-01-01

281

Performance assessment of Tao–Mason equation of state: Results for vapor–liquid equilibrium properties  

Microsoft Academic Search

The present work evaluates the performance of a molecular-based equation of state in predicting thermodynamic properties of several fluids in a very wide range of temperatures encompassing 100K

Mohammad Mehdi Papari; Masoumeh Kiani; Jalil Moghadasi

2011-01-01

282

Potential applications of artificial neural networks to thermodynamics: vapor–liquid equilibrium predictions  

Microsoft Academic Search

The associative property of artificial neural networks (ANNs) and their inherent ability to “learn” and “recognize” highly non-linear and complex relationships finds them ideally suited to a wide range of applications in chemical engineering. Dynamic Modeling and Control of Chemical Process Systems and Fault Diagnosis are the two significant applications of ANNs that have been explored so far with success.

Raj Sharma; Diwakar Singhal; Ranjana Ghosh; Ashish Dwivedi

1999-01-01

283

EXPERIMENTAL MEASUREMENT AND MODELING OF THE VAPOR-LIQUID EQUILIBRIUM OF CARBON DIOXIDE + CHLOROFORM. (R826734)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

284

Determination of vapor-liquid equilibrium at far-subatmospheric pressures by using headspace chromatography  

Microsoft Academic Search

Isothermal VLE data for the ethanol-n-butyl acetate binary system at 303.15 K, 313.15 K, and 318.15 K, and for the cyclohexane-2-propanol binary system at 298.15 K and 303.15 K, have been determined using headspace chromatography. These data have not been reported in the literature. The thermodynamic consistency of the T-x-y data in the present work has been tested by means

Gao Zhenghong; Cui Zhiyu; Gan Yongsheng; Li Jingqing

1996-01-01

285

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

286

Isothermal vapor-liquid equilibria for the binary systems of chlorine with difluoromethane, chlorodifluoromethane, and dichlorodifluoromethane at 10 C  

Microsoft Academic Search

Isothermal vapor-liquid equilibria for difluoromethane + chlorine, chlorodifluoromethane + chlorine, and dichlorodifluoromethane + chlorine have been measured. The experimental data are correlated with the Peng-Robinson equation of state, and the relevant parameters are presented. All of the binary systems form minimum boiling homogeneous azeotropes at the experimental conditions. The correlation of the vapor-liquid equilibria was found to be in good

Yun Whan Kang; Sung Yong Cho; In Wook Nah

1998-01-01

287

High-pressure vapor-liquid equilibria involving mixtures of nitrogen, carbon dioxide, and eta-butane  

SciTech Connect

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 and the previously unmeasured nitrogen + carbon dioxide + n-butane system. These data were modeled with the Peng-Robinson equation of state. Excellent fits were obtained for the compositions in the carbon dioxide + n-butane system, but a poor fit was obtained for the nitrogen + n-butane data. The ability of the Peng-Robinson equation of state to accurately predict the phase behavior of the ternary mixture is dependent on the fits of the binary data, and therefore the ternary data are also not fit well. In all cases the liquid densities are poorly predicted with the Peng-Robinson equation of state.

Shibata, S.K. (Du Pont de Nemours (E.I.) and Co., Wilmington, DE (USA). Technical Div.); Sandler, S.I. (Delaware Univ., Newark, DE (USA). Dept. of Chemical Engineering)

1989-07-01

288

Vapor-liquid equilibria and heat effects of hydrogen fluoride from molecular simulation  

Microsoft Academic Search

The vapor-liquid coexistence densities, vapor pressure, and heat of vaporization of hydrogen fluoride (HF) is calculated via Monte Carlo simulation from three intermolecular potential models that are found in the literature. The first is a pure pair potential based solely on ab initio data, the second is a semi-empirical pair potential which uses an ab initio derived surface fitted with

Donald P. Visco; David A. Kofke

1998-01-01

289

Vapor–liquid equilibria and heat effects of hydrogen fluoride from molecular simulation  

Microsoft Academic Search

The vapor–liquid coexistence densities, vapor pressure, and heat of vaporization of hydrogen fluoride (HF) is calculated via Monte Carlo simulation from three intermolecular potential models that are found in the literature. The first is a pure pair potential based solely on ab initio data, the second is a semi-empirical pair potential which uses an ab initio derived surface fitted with

Donald P. Visco; David A. Kofke

1998-01-01

290

Evaporation rates and free-energy scaling properties of clusters in vapor liquid nucleation  

Microsoft Academic Search

Two unique properties of clusters in the 30-500 molecule range typical of critical nuclei in vapor liquid nucleation are described: Recent density functional calculations, in collaboration with Ari Laaksonen of the University of Helsinki, for the free-energy of clusters in this size range, show strong and systematic departure from predictions based on the capillarity approximation, which assigns bulk phase properties

Robert McGraw

1996-01-01

291

Split vapor\\/liquid fuel supply system for internal combustion engines  

Microsoft Academic Search

A split vapor\\/liquid fuel supply system is described for an internal combustion engine having: an intake manifold leading to at least one combustion chamber, a fuel tank holding a liquid hydrocarbon fuel supply, a carburetor connected to the fuel supply for feeding fuel to the engine, air supply means for supplying engine intake air to the carburetor for mixing with

La Pan

1987-01-01

292

Vapor-liquid equilibria of the trimethyl borate (1)-trichloroethylene (2) system  

SciTech Connect

Vapor-liquid equilibria for the binary system trimethyl borate (1)-trichloroethylene (2) have been measured at 101.325 kPa. Data is shown to approach ideality and could also be reasonably represented by a constant relative volatility {alpha}/sub 12/ = 1.782.

Owensby, G.S.; Plank, C.A.; Laukhuf, W.L.S. (Louisville Univ., KY (USA). Dept. of Chemical and Environmental Engineering)

1989-04-01

293

Vapor-liquid phase transition and multifragmentation of nuclei  

SciTech Connect

Nucleation theory based on the steady-state solution of Fokker-Plank kinetic equation is applied to study of the liquid-gas phase transition in nuclear matter. Theoretical predictions are compared with the parameters extracted from the analysis of the charge distributions of fragments in heavy ion collisions at intermediate energies. The phenomenological droplet model is shown to be able to explain both the characteristic power-law falloff and the long tail of the yields of light and heavy nuclear fragments correspondingly. It is shown that the traditional equilibrium approach to the analysis of the multifragmentation data leads to significant overestimation of the parameters of nuclear equation of state.

Zabrodin, E.E. [Department of Physics, University of Bergen, Allegaten 55, N-5007 Bergen (Norway)]|[Institute for Nuclear Physics, Moscow State University, 119899 Moscow (Russian Federation)

1995-11-01

294

Vapor liquid equilibria on the ternary lithium fluoride-sodium fluoride-beryllium fluoride system  

NASA Astrophysics Data System (ADS)

Molten mixtures of LiF, NaF, and BeF2 (FLiNaBe) have been proposed as a liquid first wall for selected fusion reactor designs. Because currently envisaged reactor technologies for igniting and/or sustaining a, fusion reaction require vacuum conditions, the volatility of these liquids is an issue for concern. Many physical properties of the ternary LiF-NaF-BeF 2 (FLiNaBe) system have already been studied as part of the molten salt reactor program, but the vapor pressure has not been measured. A study of the vapor liquid equilibrium of FLiNaBe by Thermogravimetric Analysis (TGA) and Knudsen Cell Mass Spectrometry (KCMS) is presented. The ternary system is treated as a pseudo-binary system by fixing the ratio of LiF:NaF and varying the amount of BeF2. Measurements have been performed over a composition range of 0.3--0.8 mole fraction BeF2 and from 875--975K. Experimental data, are correlated in terms of the BeF 2 activity coefficient. Measurements were also carried out on the binary systems LiF-BeF2 and NaF-BeF2. Measured values of the BeF2 activity coefficient in the binary LiF-BeF2 and NaF-BeF2 systems compare satisfactorily with previous results published in the research literature. The vapor phase of FLiNaBe was found to consist of primarily the species BeF2, LiBeF3, and NaBeF 3 over the temperature and composition range studied. Mixtures of BeF2-containing fluoride salts are highly non-ideal; the BeF2 activity coefficient exhibits both positive and negative deviations from ideality over the composition range studied. An associated solution model with 3 adjustable parameters is used to fit the BeF2 activity coefficient data of the LiF-BeF2 and NaF-BeF2 systems. The parameters obtained from fitting binary data are then used to fit the ternary system. The extension of the model to the ternary system results in a single additional parameter that can only be determined from fitting ternary data. Overall the agreement between the model and experimental data is within ˜30% and the model can be used to predict the vapor pressure over a wide composition range.

Fukuda, Grant Takeshi

295

Concise nuclear isobar charts  

SciTech Connect

In the Concise Nuclear Isobar Charts, data on binding energies of protons and neutrons in the ground state and excitation energies for low-lying nuclear energy levels are displayed, both of which are of great interest for transition processes as well as for questions of nuclear structure. Also, quantum numbers for angular momentum and parity are shown for these energy levels. For the stable nuclei, data for the relative abundances, and for unstable nucleon configurations, the transition probabilities are included in the data displayed. Due to the representation chosen for the atomic nuclei, in many cases a very clear first survey of systematic properties of nuclear energy states as well as spontaneous decay processes is achieved.

Bucka, H.

1986-01-01

296

Polarization Near Isobaric Analogue Resonances.  

National Technical Information Service (NTIS)

For the purpose of analysing isobaric analogue resonances, a single-level resonance formula has been incorporated into nuclear scattering amplitudes found with an optical-model potential. The inclusion of the resonance term leads to polarization magnitude...

J. L. Adams W. J. Thompson D. Robson

1966-01-01

297

Phase equilibrium measurements on twelve binary mixtures  

Microsoft Academic Search

Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin;

Neil F. Giles; Howard L. Wilson; W. Vincent Wilding

1996-01-01

298

Molecular dynamics study of nonequilibrium processes of evaporation and condensation at a vapor-liquid interface  

NASA Astrophysics Data System (ADS)

Nonequilibrium processes of evaporation and condensation at a vapor-liquid interface are studied by molecular dynamics simulations, which is devised to be free from any artificial constraints on molecular motions in the vicinity of the interface. To decrease statistical fluctuations on the results, the dynamics of a vapor-liquid two-phase system of almost 0.3 million Lennard-Jones molecules is simulated for more than 107 steps. The system with a steady evaporation or condensation mass flux can be realized by driving two vapor regions on the both sides of a planar liquid film, and thus the simulation is free from artificial controls of molecular motions in the liquid film and in the neighborhood of the interfaces. This enables us to evaluate the mass, momentum, and energy fluxes, which are relevant to the velocity distribution of molecules leaving the interface when the nonequilibrium evaporation or condensation occurs there.

Yano, Takeru

2012-11-01

299

Joule-Thomson Inversion in Vapor-Liquid-Solid Solution Systems  

NASA Astrophysics Data System (ADS)

Solid phase precipitation can greatly affect thermal effects in isenthalpic expansions; wax precipitation may occur in natural hydrocarbon systems in the range of operating conditions, the wax appearance temperature being significantly higher (as high as 350 K) for hyperbaric fluids. Recently, methods for calculating the Joule-Thomson inversion curve (JTIC) for two-phase mixtures, and for three-phase vapor-liquid-multisolid systems have been proposed. In this study, an approach for calculating the JTIC for the vapor-liquid-solid solution systems is presented. The JTIC is located by tracking extrema and angular points of enthalpy departure variations versus pressure at isothermal conditions. The proposed method is applied to several complex synthetic and naturally occurring hydrocarbon systems. The JTIC can exhibit several distinct branches (which may lie within two- or three-phase regions or follow phase boundaries), multiple inversion temperatures at fixed pressure, as well as multiple inversion pressures at given temperature.

Nichita, Dan Vladimir; Pauly, Jerome; Daridon, Jean-Luc

2009-07-01

300

Isobaric groundwater well  

SciTech Connect

A method is described for measuring a parameter in a well, under isobaric conditions, including such parameters as hydraulic gradient, pressure, water level, soil moisture content and/or aquifer properties. The method as presented comprises providing a casing having first and second opposite ends, and a length between the ends, the casing supporting a transducer having a reference port; placing the casing lengthwise into the well, second end first, with the reference port vented above the water table in the well; and sealing the first end. A system is presented for measuring a parameter in a well, the system comprising a casing having first and second opposite ends, and a length between the ends and being configured to be placed lengthwise into a well second end first; a transducer, the transducer having a reference port, the reference port being vented in the well above the water table, the casing being screened across and above the water table; and a sealing member sealing the first end. In one embodiment, the transducer is a tensiometer transducer and in other described embodiments, another type transducer is used in addition to a tensiometer.

Hubbell, J.M.; Sisson, J.B.

1999-10-19

301

A theory of a curved vapor-liquid separation boundary: The lattice gas model  

Microsoft Academic Search

Molecular theory of curved vapor-liquid interphase boundaries was considered in terms of the lattice gas model. The theory\\u000a uses the quasi-thermodynamic concept of curved layers of a separation boundary with a large radius. The transition from a\\u000a rectangular lattice to such layers is performed by the introduction of a variable number of the nearest neighbors. The problems\\u000a (1) of the

Yu. K. Tovbin

2010-01-01

302

Measurement and correlation of vapor–liquid equilibria for the system carbon dioxide–diisopropyl ether  

Microsoft Academic Search

A view cell with on-line sampling of the vapor and the liquid phase has been built for measuring vapor–liquid equilibria data under high pressure. The samples are analyzed by gas chromatography. VLE data for the system carbon dioxide–diisopropyl ether has been measured at 265.15–333.15K and 0.5–2.5MPa. The isothermal data were correlated using the Peng–Robinson equation. The correlated results agree well

Caifeng Zhu; Xianghong Wu; Danxing Zheng; Wei He; Shuhong Jing

2008-01-01

303

Probe card with probe pins grown by the vapor-liquid-solid (VLS) method  

Microsoft Academic Search

Probe cards mounted with vapor-liquid-solid (VLS) grown silicon whiskers have been produced. In this development the “mesa method”, in which VLS whiskers are grown on silicon mesas topped with gold hats, has been successfully introduced which allows accurate positioning of the VLS whiskers. The VLS whisker grows vertically to over 2000 ?m in length and a diameter of 10-100 ?m

S. Asai; K. Kato; N. Nakazaki; Y. Nakajima

1996-01-01

304

The experimental application of X-ray tomography to a vapor–liquid contactor  

Microsoft Academic Search

Initial results obtained from the application of X-ray tomography to an operating vapor–liquid contactor indicate that the technology has the potential to provide insight into the underlying hydraulic behavior of a packed column. Experiments were performed with counter-current air–water flows in a 6-in-diameter contactor packed with random packing. Liquid and gas velocities typical of a commercial column were tested. Liquid

Carolyn E. Schmit; Dwight B. Cartmel; R. Bruce Eldridge

2001-01-01

305

Influence of precursor feeding rate on vapor–liquid–solid nanowire growth  

Microsoft Academic Search

The yield of Ge nanowires (NWs) synthesized using the vapor–liquid–solid (VLS) method was discovered to be highly sensitive\\u000a to the rate of precursor feeding. When other parameters were fixed, fast filling of precursors yielded nearly 100% Ge NWs\\u000a with regard to the growth seeds. By contrast, slow feeding produced nearly no or very low yield of Ge NWs. The dramatic

Guangbi Yuan; Xiaohua Liu; Weidong He; Dunwei Wang

2009-01-01

306

High-pressure vapor–liquid 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 vapor–liquid 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 Gläser

2006-01-01

307

Thermodynamic models for vapor–liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures  

Microsoft Academic Search

For the design and optimization of CO2 recovery from alcoholic fermentation processes by distillation, models for vapor–liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng–Robinson equation of state (EOS) and a model based on Henry’s law constants, are proposed for the ternary mixture N2+O2+CO2. Pure substance parameters of the Peng–Robinson EOS are taken from the literature, whereas the

Jadran Vrabec; Gaurav Kumar Kedia; Ulrich Buchhauser; Roland Meyer-Pittroff; Hans Hasse

2009-01-01

308

On the Electronic Nature of the Surface Potential at the Vapor-Liquid Interface of Water  

SciTech Connect

The surface potential at the vapor-liquid interface of water is relevant to many areas of chemical physics. Measurement of the surface potential has been experimentally attempted many times, yet there has been little agreement as to its magnitude and sign (-1.1 to +0.5 mV). We present the first computation of the surface potential of water using ab initio molecular dynamics. We find that the surface potential {chi} = -18 mV with a maximum interfacial electric field = 8.9 x 10{sup 7} V/m. A comparison is made between our quantum mechanical results and those from previous molecular simulations. We find that explicit treatment of the electronic density makes a dramatic contribution to the electric properties of the vapor-liquid interface of water. The E-field can alter interfacial reactivity and transport while the surface potential can be used to determine the 'chemical' contribution to the real and electrochemical potentials for ionic transport through the vapor-liquid interface.

Kathmann, S M; Kuo, I; Mundy, C J

2008-02-05

309

Study of the Vapor-Liquid Equilibria Used in the Fabrication Process of Hydrogen by Thermochemistry: Final Report.  

National Technical Information Service (NTIS)

Two new flow apparatuses have been designed and constructed to determine vapor-liquid equilibria of very corrosive components. Main differences between the two apparatuses are their temperature and pressure ranges of operation. When using each of the two ...

P. Berthelot C. Houzelle S. Laugier D. Legret R. Muehbauer

1986-01-01

310

Isothermal vapor-liquid equilibria for the binary systems of chlorine with difluoromethane, chlorodifluoromethane, and dichlorodifluoromethane at 10 C  

SciTech Connect

Isothermal vapor-liquid equilibria for difluoromethane + chlorine, chlorodifluoromethane + chlorine, and dichlorodifluoromethane + chlorine have been measured. The experimental data are correlated with the Peng-Robinson equation of state, and the relevant parameters are presented. All of the binary systems form minimum boiling homogeneous azeotropes at the experimental conditions. The correlation of the vapor-liquid equilibria was found to be in good agreement with the experimental data.

Kang, Y.W.; Cho, S.Y.; Nah, I.W. [KIST, Seoul (Korea, Republic of)

1998-07-01

311

Application of an extended Lee-Kesler corresponding-states technique to prediction of vapor-liquid equilibria in multicomponent mixtures containing polar components  

NASA Astrophysics Data System (ADS)

Mixing rules for an extended Lee-Kesler (ELK) corresponding-states method for prediction of thermodynamic properties are presented. The mixing rules, which do not contain adjustable parameters, permit calculation of vapor-liquid equilibria in mixtures containing one or more polar components. While a single heat-of-mixing datum may be included for strongly associating components, generally only pure component properties are used in the calculations. A comparison of calculated bubble-point pressures and equilibrium vaporization ratios to experimental values is made for 26 ternary mixtures (791 points) and 5 quaternary mixtures (175 points). Bubble-point pressures are predicted quite well with ELK (9.1 % AAD for ternaries and 7.9% for quaternaries). Composition predictions are difficult to compare in multicomponent systems, but ELK predictions appear to be acceptable on both a system-by-system and an overall AAD basis.

Johnson, J. K.; Rowley, R. L.

1989-03-01

312

Theory of Isobaric-Spin Analogue Resonances  

Microsoft Academic Search

A theory of isobaric-spin analogue resonances is developed by considering a potential model which has an isobaric-spin-dependent component. The occurrence of isobaric states as compound-nucleus resonances is shown to be a natural consequence of the formalism previously used to explain the excitation of isobaric analogue states by the direct-interaction charge-exchange mechanism. The results are then generalized on the basis of

D. Robson

1965-01-01

313

Theory of Isobaric-Spin Analogue Resonances.  

National Technical Information Service (NTIS)

A theory of isobaric-spin analogue resonances is developed by considering a potential model which has an isobaric-spin-dependent component. The occurrence of isobaric states as compound-nucleus resonances is shown to be a natural consequence of the formal...

D. Robson

1964-01-01

314

Vapor-liquid critical and interfacial properties of square-well fluids in slit pores  

NASA Astrophysics Data System (ADS)

Vapor-liquid phase equilibria of square-well (SW) fluids of variable interaction range: ??=1.25, 1.75, 2.0, and 3.0 in hard slit pores are studied by means of grand-canonical transition-matrix Monte Carlo (GC-TMMC) simulation. Critical density under confinement shows an oscillatory behavior as slit width, H, reduced from 12? to 1?. Two linear regimes are found for the shift in the critical temperature with the inverse in the slit width. The first regime is seen for H>2.0? with linear increase in the slope of shift in the critical temperature against inverse slit width with increasing interaction range. Subsequent decrease in H has little consequence on the critical temperature and it remains almost constant. Vapor-liquid surface tensions of SW fluids of variable well extent in a planar slit pore of variable slit width are also reported. GC-TMMC results are compared with that from slab based canonical Monte Carlo and molecular dynamics techniques and found to be in good agreement. Although, vapor-liquid surface tension under confinement is found to be lower than the bulk surface tension, the behavior of surface tension as a function of temperature is invariant with the variable pore size. Interfacial width, ?, calculated using a hyperbolic function increases with decreasing slit width at a given temperature, which is contrary to what is being observed recently for cylindrical pores. Inverse scaled interfacial width (?/H), however, linearly increases with increase in the scaled temperature (Tc,bulk-T)/Tc,bulk.

Jana, Subimal; Singh, Jayant K.; Kwak, Sang Kyu

2009-06-01

315

Prediction of viscosities and vapor–liquid equilibria for five polyhydric alcohols by molecular simulation  

Microsoft Academic Search

Reverse nonequilibrium molecular dynamics in the canonical ensemble and coupled–decoupled configurational-bias Monte Carlo simulations in the Gibbs ensemble were used to predict the low-shear rate Newtonian viscosities and vapor–liquid coexistence curves for 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, and 1,2,4-butanetriol modeled with the transferable potentials for phase equilibria-united atom (TraPPE-UA) force field. Comparison with available experimental data demonstrates that the TraPPE-UA force

Manish S. Kelkar; Jake L. Rafferty; Edward J. Maginn; J. Ilja Siepmann

2007-01-01

316

Vapor-liquid equilibria of binary mixtures with ethyl tert-butyl ether  

SciTech Connect

In this work P-T-x-y vapor-liquid equilibria were obtained for ethyl tert-butyl ether (ETBE) + toluene at temperatures of 273.15, 311.15, and 333.15 K and for 2-methylbutane (isopentane) + ETBE at temperatures of 293.15 and 303.15 K. These mixtures are found to be almost ideal, and the reported data are well described using a Peng-Robinson equation of state, modified by Stryjek and Vera with the van der Waals one-fluid mixing rule.

Steinhagen, V. (Technische Univ., Berlin (Germany). Inst. fuer Thermodynamik und Reaktionstechnik); Sandler, S.I. (Univ. of Delaware, Newark, DE (United States). Dept. of Chemical Engineering)

1994-07-01

317

Vapor-liquid equilibria of hydrocarbons and tert-amyl methyl ether  

SciTech Connect

The P-T-x-y data for tert-amyl methyl ether (TAME) separately with 2,2,4-trimethylpentane (TMP), methylcyclohexane (MCHX), and toluene were obtained at three temperatures, 293, 311, and 333 K. The vapor-liquid equilibria of a five-components mixture (TAME + TMP + 1-heptene + MCHX + toluene) at the same temperature were measured as well. The data reported have been successfully described using a Peng-Robinson equation of state with van der Waals one-fluid mixing rules.

Antosik, M. (Polish Academy of Sciences, Warszawa (Poland). Inst. of Physical Chemistry); Sandler, S.I. (Univ. of Delaware, Newark, DE (United States). Dept. of Chemical Engineering)

1994-07-01

318

Vapor-liquid equilibria for difluoromethane (R32) + and pentafluoroethane (R125) + 1,1,1,3,3,3-hexafluoropropane (R236fa) at 303.2 and 323.3 K  

Microsoft Academic Search

Isothermal vapor-liquid equilibria (VLE) for the binary systems difluoromethane (R32) + 1,1,1,3,3,3-hexafluoropropane (R236fa) and pentafluoroethane (R125) + 1,1,1,3,3,3-hexafluoropropane (R236f) were measured at 303.2 and 323.3 K using a recirculation apparatus in which the vapor phase was forced through the liquid. The phase composition at equilibrium was measured by gas chromatography, calibrating its response using gravimetrically prepared mixtures. Both systems show

Sergio Bobbo; Roberto Camporese; Roman Stryjek

1999-01-01

319

Stripping to Isobaric Analog Resonances  

Microsoft Academic Search

The form factor for the stripping distorted-wave Born-approximation amplitude to isobaric analog resonances is derived using a fine-structure theory of these resonances. It is found that the corrections due to compound-nucleus mixing are small. Using the derived form factor, the spectroscopic factors are calculated for the reaction Mo92(He3, d)Tc93.

D. Agassi; N. Auerbach; A. Moalem

1972-01-01

320

Phase-equilibrium properties of coal-derived liquids. Technical progress report, January-June 1981  

Microsoft Academic Search

On July 1, 1980, work was initiated on a program for experimental vapor liquid equilibrium measurements on coal derived liquids. During the last six months design of the equilibrium flash vaporization system was completed and all major equipment was delivered. Most of the construction work of the system was also completed. Construction and evaluation of the equipment should be completed

V. F. Yesavage; A. J. Kidnay

1981-01-01

321

Azeotropic phase equilibrium diagrams: a survey  

Microsoft Academic Search

An analysis of the structural properties of vapor–liquid equilibrium (VLE) diagrams provides a fundamental understanding of the thermodynamic behavior of azeotropic mixtures upon distillation.In addition to a review of well-known fundamental work on the analysis of VLE diagrams, this survey comprises less-known published results, especially from the Russian literature. Some new results are also presented for the first time.

V. N. Kiva; E. K. Hilmen; S. Skogestad

2003-01-01

322

Review Azeotropic phase equilibrium diagrams: a survey  

Microsoft Academic Search

An analysis of the structural properties of vapor-liquid equilibrium (VLE) diagrams provides a fundamental understanding of the thermodynamic behavior of azeotropic mixtures upon distillation. In addition to a review of well-known fundamental work on the analysis of VLE diagrams, this survey comprises less-known published results, especially from the Russian literature. Some new results are also presented for the 6rst time.

V. N. Kiva; E. K. Hilmen; S. Skogestad

323

Comparison of the performance of the LCVM model (an EoS\\/G E model) and the PHCT EoS (the Perturbed Hard Chain Theory Equation of State) in the prediction of the Vapor–Liquid Equilibria of binary systems containing light gases  

Microsoft Academic Search

The purpose of this work is to compare two models, which are able to perform Vapor–Liquid Equilibrium (VLE) predictions. The first one, the LCVM model, is an EoS\\/GE one and it has been successfully applied in the prediction of the VLE behavior of polar and non-polar systems, as well as, systems of dissimilar component size, such as those containing gases

Christos J. Boukouvalas; Kostis G. Magoulas; Dimitrios P. Tassios; Ireneo Kikic

2001-01-01

324

Oscillatory Mass Transport in Vapor-Liquid-Solid Growth of Sapphire Nanowires  

SciTech Connect

In vapor-liquid-solid (VLS) growth, the liquid phase plays a pivotal role in mediating mass transport from the vapor source to the growth front of a nanowire. Such transport often takes place through the liquid phase. However, we observed by in situ transmission electron microscopy a different behavior for self-catalytic VLS growth of sapphire nanowires. The growth occurs in a layer-by-layer fashion and is accomplished by interfacial diffusion of oxygen through the ordered liquid aluminum atoms. Oscillatory growth and dissolution reactions at the top rim of the nanowires occur and supply the oxygen required to grow a new (0006) sapphire layer. A periodic modulation of the VLS triple-junction configuration accompanies these oscillatory reactions.

Oh, Sang Ho [ORNL; Chisholm, Matthew F [ORNL; Kauffmann, Yaron [Technion-Israel Institute of Technology, Haifa, Israel; Kaplan, Prof. Wayne D. [Technion, Israel Institute of Technology; Luo, Weidong [ORNL; Ruhle, M. [Max-Planch-Institut fur Metallforschang, Germany; Scheu, Christina [Ludwig-Maximilian University

2010-01-01

325

Vapor-liquid phase equilibria of water modelled by a Kim-Gordon potential  

SciTech Connect

Gibbs ensemble Monte Carlo simulations were carried out to investigate the properties of a frozen-electron-density (or Kim-Gordon, KG) model of water along the vapor-liquid coexistence curve. Because of its theoretical basis, such a KG model provides for seamless coupling to Kohn-Sham density functional theory for use in mixed quantum mechanics/molecular mechanics (QM/MM) implementations. The Gibbs ensemble simulations indicate rather limited transferability of such a simple KG model to other state points. Specifically, a KG model that was parameterized by Barker and Sprik to the properties of liquid water at 300 K, yields saturated vapor pressures and a critical temperature that are significantly under- and over-estimated, respectively.

Maerzke, K A; McGrath, M J; Kuo, I W; Tabacchi, G; Siepmann, J I; Mundy, C J

2009-03-16

326

Vapor-liquid nucleation of argon: Exploration of various intermolecular potentials  

NASA Astrophysics Data System (ADS)

The homogeneous vapor-liquid nucleation of argon has been explored at T=70 and 90 K using classical nucleation theory, semiempirical density functional theory, and Monte Carlo simulations using the aggregation-volume-bias algorithm with umbrella sampling and histogram-reweighting. In contrast with previous simulation studies, which employed only the Lennard-Jones intermolecular potential, the current studies were carried out using various pair potentials including the Lennard-Jones potential, a modified Buckingham exponential-six potential, the Barker-Fisher-Watts pair potential, and a recent ab initio potential developed using the method of effective diameters. It was found that the differences in the free energy of formation of the critical nuclei between the potentials cannot be explained solely in terms of the difference in macroscopic properties of the potentials, which gives a possible reason for the failure of classical nucleation theory.

McGrath, Matthew J.; Ghogomu, Julius N.; Tsona, Narcisse T.; Siepmann, J. Ilja; Chen, Bin; Napari, Ismo; Vehkamäki, Hanna

2010-08-01

327

Vapor-liquid interfacial dynamics and related liquid nitrogen boiling on perforated plates  

NASA Astrophysics Data System (ADS)

For the switch from terrestrial gravity ("1 g") to micro-gravity, we investigate vapor-liquid interfaces and their control in simulation studies and experiments. An improved level set method is presented for vapor bubble kinematics prediction. In view of a wide range of vapor bubble dynamics phenomena, our initial experimental investigations have focused on film boiling in and near perforated plates immersed in liquid nitrogen. A "zeroth order" approximation of transport based on minimum energy expenditure rates provides information on mean field vapor thickness. We have measured thermal conductance for the zero net mass flow case and finite mass flow. The data are compared with results obtained in comparison runs for single solid plates.

Miller, B.; Merriman, B.; Rafique, K.; Osher, S.; Noushkam, N.; Spletzer, A.; Frederking*, T. H. K.

1999-07-01

328

Engineering scale development of the Vapor-Liquid-Solid (VLS) process for the production of silicon carbide fibrils.  

National Technical Information Service (NTIS)

Vapor-liquid-solid (VLS)SiC fibrils are used as reinforcement in ceramic matrix composites (CMC). A program has been completed for determining process scaleup parameters and to produce material for evaluation in a CMC. The scaleup is necessary to lower pr...

W. E. Hollar W. H. Mills

1993-01-01

329

Vapor-liquid equilibria for the systems difluoromethane + hydrogen fluoride, dichlorodifluoromethane + hydrogen fluoride, and chlorine + hydrogen fluoride  

Microsoft Academic Search

Isothermal vapor-liquid equilibria for difluoromethane + hydrogen fluoride, dichlorodifluoromethane + hydrogen fluoride, and chlorine + hydrogen fluoride have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. The binary system difluoromethane + hydrogen fluoride forms a homogeneous

Yun Whan Kang

1998-01-01

330

Vapor-liquid equilibria for the systems difluoromethane + chlorodifluoromethane, difluoromethane + dichlorodifluoromethane, and difluoromethane + chloromethane at 10.0 C  

Microsoft Academic Search

Isothermal vapor-liquid equilibria for the three binary systems (difluoromethane + chlorodifluoromethane, difluoromethane + dichlorodifluoromethane, and difluoromethane + chloromethane) have been measured at 10.0 C. The experimental data for the binary systems are correlated with the Wilson equation and the relevant parameters are presented. The difluoromethane + dichlorodifluoromethane system forms a minimum boiling azeotrope, but the others do not.

Yun Whan Kang; Kun Yong Chung

1996-01-01

331

Phase equilibrium studies  

SciTech Connect

A phase equilibrium model has been developed for the SRC-I process, as well as the other coal liquefaction processes. It is applicable to both vapor/liquid and liquid/liquid equilibria; it also provides an approximate but adequate description of aqueous mixtures where the volatile electrolyte components dissociate to form ionic species. This report completes the description of the model presented in an earlier report (Mathias and Stein, 1983a). Comparisons of the model to previously published data on coal-fluid mixtures are presented. Further, a preliminary analysis of new data on SRC-I coal fluids is presented. Finally, the current capabilities and deficiencies of the model are discussed. 25 references, 17 figures, 30 tables.

Mathias, P.M.; Stein, F.P.

1983-09-01

332

Salt effect in vapor-liquid equilibria: correlation of alcohol-, water-, salt systems  

Microsoft Academic Search

The isobaric data of Johnson and Furter for the systems methanol-water, ethanol-water, and l-propanol water, each saturated with a variety of common inorganic salts, can be effectively correlated by means of the van Laar, the Wilson or the Renon equations if pseudo-activity coefficients for the volatile components are computed using a modified reference fugacity for the liquid phase. This reference

R. W. Rousseau; D. L. Ashcraft; E. M. Schoenborn

1972-01-01

333

Prediction of the vapor-liquid distribution constants for volatile nonelectrolytes in water up to its critical temperature  

NASA Astrophysics Data System (ADS)

The distribution of solutes between coexisting liquid and vapor phases of water can be expressed by the distribution constant, K D, defined as K D= limitlim x?0y/x, where y and x stand for the mole fraction concentrations of a solute in vapor and liquid phases, respectively. Research reported here is concerned with the prediction of this property, K D, for volatile nonelectrolytes, over the whole temperature range of existence of the vapor-liquid equilibrium for water, i.e. from 273 K to the critical temperature at 647.1 K. A simple empirical method is proposed to extrapolate the values of K D from 298 K to 500-550 K. Calculations at higher temperatures are based on the theoretical relation that establishes the proportionality between RTlnK D and the Krichevskii parameter, A Kr, which is the single most important property of a solute at near-critical conditions, and can be evaluated using the method proposed here. The comparison of predicted and experimental values of K D and A Kr for a few well-studied solutes reveals the satisfactory performance of the proposed method. It appears that the accuracy of predictions in the framework of this method is limited mainly by the accuracy of the values of the thermodynamic functions of hydration of solutes at 298 K, and that the best way to improve the quality of predictions of K D and A Kr is to increase the inventory of accurate calorimetric enthalpy and heat capacity data for aqueous solutes at 298 K. We stress that the values of the Krichevskii parameter, such as those generated in this study, are of crucial importance for reliable predictions of the chemical potential and its derivatives (V 2o, Cp 2o) for aqueous solutes at near-critical and supercritical conditions. Values of K D and A Kr are predicted for many inorganic volatile nonelectrolytes and some halogenated derivatives of methane and ethene. We show that both ln K D and A Kr for aqueous organic solutes follow group additivity systematics, and we derive a set of corresponding group contribution values for several functional groups (material point, CH 3, CH 2, CH, C, C = C, HC = CH, C?C, HC ar, C ar, C fus, OH, O, S, SH, CO, COO, COH, COOH, CN, F, Cl, Br, NH 2, NH, N, etc.).

Plyasunov, Andrey V.; Shock, Everett L.

2003-12-01

334

Vapor-liquid-solid growth of silicon and silicon germanium nanowires  

NASA Astrophysics Data System (ADS)

Si and Si1-xGex nanowires are promising materials with potential applications in various disciplines of science and technology. Small diameter nanowires can act as model systems to study interesting phenomena such as tunneling that occur in the nanometer regime. Furthermore, technical challenges in fabricating nanoscale size devices from thin films have resulted in interest and research on nanowires. In this perspective, vertical integrated nanowire field effect transistors (VINFETs) fabricated from Si nanowires are promising devices that offer better control on device properties and push the transistor architecture into the third dimension potentially enabling ultra-high transistor density circuits. Transistors fabricated from Si/Si 1-xGex nanowires have also been proposed that can have high carrier mobility. In addition, the Si and Si1-xGe x nanowires have potential to be used in various applications such as sensing, thermoelectrics and solar cells. Despite having considerable potential, the understanding of the vapor-liquid-solid (VLS) mechanism utilized to fabricate these wires is still rudimentary. Hence, the objective of this thesis is to understand the effects of nanoscale size and the role of catalyst that mediates the wire growth on the growth rate of Si and Si1-xGe x nanowires and interfacial abruptness in Si/Si1-xGe x axial heterostructure nanowires. Initially, the growth and structural properties of Si nanowires with tight diameter distribution grown from 10, 20 and 50 nm Au particles dispersed on a polymer-modified substrate was studied. A nanoparticle application process was developed to disperse Au particles on the substrate surface with negligible agglomeration and sufficient density. The growth temperature and SiH4 partial pressure were varied to optimize the growth conditions amenable to VLS growth with smooth wire morphology and negligible Si thin film deposition on wire sidewalls. The Si nanowire growth rate was studied as a function of growth time, temperature, SiH4 partial pressure and wire diameter and discussed in the context of the literature. The wire growth rate was found to increase with wire diameter in agreement with a size-related effect known as the Gibbs-Thomson effect. Subsequently, the effect of P and Sb doping on the growth rate and structural properties of Si nanowires was investigated. A reduction in wire growth rate was observed upon doping, which was pronounced in case of Sb doping, ascribable to P/Sb segregation at the vapor-liquid interface (catalyst surface) and the liquid-solid interface (growth front) that in turn reduces Si incorporation at these interfaces. The second part of thesis was focused on the Si1-xGe x alloy nanowires. The effect of wire diameter and growth conditions on the interfacial abruptness of Si/Si1-xGex heterostructure nanowires was examined. Abrupt interfaces were obtained at smaller wire diameters. However, the growth temperature wasn't found to have much impact on the interfacial abruptness. These results were explained in terms of catalyst effects on the interfacial abruptness. The remaining part of the study was focused on the effect of growth conditions on the growth rate of Si1-x Gex nanowires. It was found that the Si incorporation mechanism was different between Si and Si1-xGex nanowire growth which was ascribed to changes in the gas phase or catalyst composition that can impact the SiH4 decomposition kinetics at the catalyst surface (vapor-liquid interface) and/or Si incorporation at the growth front (liquid-solid interface).

Nimmatoori, Pramod

335

Vapor-Liquid Equilibrium Model for a Partially Miscible Multicomponent System: Isopropanol-Acetone-Ethanol-N-Butanol-Water.  

National Technical Information Service (NTIS)

Normal butanol, a potential diesel fuel additive, can be produced by the fermentation of paper pulp waste streams by Clostridia with isopropanol, acetone, and ethanol produced as byproducts. To design a distillation process for the recovery of n-butanol f...

J. H. Chronis M. Amrhein

1980-01-01

336

Application of a volume-translated Peng-Robinson equation of state on vapor-liquid equilibrium calculations  

Microsoft Academic Search

A volume-translated Peng-Robinson (VTPR) equation of state (EOS) is developed in this study. Besides the two parameters in the original Peng-Robinson equation of state, a volume correction term is employed in the VTPR EOS. In this equation, the temperature dependence of the EOS energy parameter was regressed by an improved expression which yields better correlation of pure-fluid vapor pressures. The

Jung-Chin Tsai; Yan-Ping Chen

1998-01-01

337

Measurement and estimation of vapor–liquid equilibrium for industrial sugar juice using the Peng–Robinson equation of state  

Microsoft Academic Search

The Peng–Robinson equation of state is adapted to calculate phase equilibria for industrial sugar juices using the pseudocomponent approach. These juices were characterized by sugar, amino acid, carboxylic acid and ash pseudocomponents in aqueous solution. New correlating equations are developed for calculating the pseudocomponents equation of state constants using the molecular structure. Pseudo-binary interaction parameters of Peng–Robinson equation of state

S. Abderafi; T. Bounahmidi

1999-01-01

338

Carbothermal synthesis of TaC whiskers via a vapor-liquid-solid growth mechanism  

SciTech Connect

Tantalum carbide whiskers have been synthesized via a vapor-liquid-solid (VLS) growth mechanism in the temperature region 1200{endash}1300{degree}C in nitrogen or argon. The starting materials consisted of Ta{sub 2}O{sub 5}, C, Ni and NaCl. Carbon was added to reduce tantalum pentoxide, via a carbothermal reduction process, and Ni was used to catalyze the whisker growth. Thermodynamic calculations showed that tantalum is transported in the vapor phase as an oxochloride rather than as a chloride. An alkali metal chloride such as NaCl can be used as a source of Cl. The formation of TaC whiskers was found to be strongly dependent on the processing conditions used, on the choice of precursor materials, e.g., their particle sizes, and on the mixing procedure. So far we have obtained TaC whisker in a yield of 75{endash}90 vol{percent}. These whiskers are 0.1{endash}0.6 {mu}m in diameter and 10{endash}30 {mu}m in length, and they are straight and exhibit smooth surfaces. The main impurities are TaC particles, minor amounts of unreacted carbon, and remnants of the Ni catalyst. {copyright} {ital 1997 Materials Research Society.}

Johnsson, M.; Nygren, M. [Department of Inorganic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm (Sweden)

1997-09-01

339

Thermodynamic models for vapor-liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures  

NASA Astrophysics Data System (ADS)

For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 + O 2 + CO 2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2-rich region.

Vrabec, Jadran; Kedia, Gaurav Kumar; Buchhauser, Ulrich; Meyer-Pittroff, Roland; Hasse, Hans

2009-02-01

340

Application of artificial intelligence control to the vapor-liquid-solid silicon carbide whisker process  

SciTech Connect

Silicon carbide whiskers have excellent mechanical and chemical properties, making them very desirable as a reinforcement for structural ceramic and other composite materials. Los Alamos has developed a laboratory-scale batch process for producing very high quality SiC whiskers by the vapor-liquid-solid (VLS) method which is an active candidate for technology transfer involving significant scale-up. The process, however, involves quite complex chemical/physical and parametric relationships and has not as yet lent itself successfully to modeling. An expert computer system was therefore developed to facilitate the transfer of this technology to industry. Optimum conditions were determined by relating the many process parameters to product results to establish a set of rules for running the process. These are incorporated in a two-phase expert system designed to guide inexperienced users. In Phase 1, an expert consultant program provides the user with information that enables him to set up the run. This information is incorporated into the rule base that makes up Phase 2 --- the control system. At present, the operator functions as the controller by responding to the decisions of the expert system; automation can be added later. 13 refs., 16 figs.

Shalek, P.D.; Parkinson, W.J.

1989-01-01

341

Vapor-liquid equilibria simulation and an equation of state contribution for dipole-quadrupole interactions.  

PubMed

A systematic investigation on vapor-liquid equilibria (VLEs) of dipolar and quadrupolar fluids is carried out by molecular simulation to develop a new Helmholtz energy contribution for equations of state (EOSs). Twelve two-center Lennard-Jones plus point dipole and point quadrupole model fluids (2CLJDQ) are studied for different reduced dipolar moments micro*2=6 or 12, reduced quadrupolar moments Q*2=2 or 4 and reduced elongations L*=0, 0.505, or 1. Temperatures cover a wide range from about 55% to 95% of the critical temperature of each fluid. The NpT+test particle method is used for the calculation of vapor pressure, saturated densities, and saturated enthalpies. Critical data and the acentric factor are obtained from fits to the simulation data. On the basis of this data, an EOS contribution for the dipole-quadrupole cross-interactions of nonspherical molecules is developed. The expression is based on a third-order perturbation theory, and the model constants are adjusted to the present 2CLJDQ simulation results. When applied to mixtures, the model is found to be in excellent agreement with results from simulation and experiment. The new EOS contribution is also compatible with segment-based EOS, such as the various forms of the statistical associating fluid theory EOS. PMID:18072758

Vrabec, Jadran; Gross, Joachim

2007-12-12

342

Directed synthesis of germanium oxide nanowires by vapor-liquid-solid oxidation  

NASA Astrophysics Data System (ADS)

We report on the directed synthesis of germanium oxide (GeOx) nanowires (NWs) by locally catalyzed thermal oxidation of aligned arrays of gold catalyst-tipped germanium NWs. During oxygen anneals conducted above the Au-Ge binary eutectic temperature (T > 361?°C), one-dimensional oxidation of as-grown Ge NWs occurs by diffusion of Ge through the Au-Ge catalyst droplet, in the presence of an oxygen containing ambient. Elongated GeOx wires grow from the liquid catalyst tip, consuming the adjoining Ge NWs as they grow. The oxide NWs’ diameter is dictated by the catalyst diameter and their alignment generally parallels that of the growth direction of the initial Ge NWs. Growth rate comparisons reveal a substantial oxidation rate enhancement in the presence of the Au catalyst. Statistical analysis of GeOx nanowire growth by ex situ transmission electron microscopy and scanning electron microscopy suggests a transition from an initial, diameter-dependent kinetic regime, to diameter-independent wire growth. This behavior suggests the existence of an incubation time for GeOx NW nucleation at the start of vapor-liquid-solid oxidation.

Gunji, M.; Thombare, S. V.; Hu, S.; McIntyre, P. C.

2012-09-01

343

Isothermal vapor-liquid equilibria for 1,1,1,2-tetrafluoroethane + propane and propane + 1,1,1,-trifluoroethane at 283.18 K  

SciTech Connect

Isothermal vapor-liquid equilibria (VLE) for the binary systems 1,1,1,2-tetrafluoroethane (R134a) + propane (R290) and propane + 1,1,1-trifluoroethane (R143a) were measured at 283.18 K using a recirculation apparatus in which the vapor phase was forced through the liquid. The phase composition at equilibrium was measured by gas chromatography, calibrating its response using gravimetrically prepared mixtures. The data were correlated using the Carnahan-Starling-De Santis and Peng-Robinson equations of state. The authors found positive homoazeotropes for R134a (1) + R290 (2) at a pressure P = 1,000.5 kPa and a composition x{sub 1} = 0.386, and for R290 (1) + R143a (2) at P = 796 kPa and x{sub 1} = 0.363. For the R134a + R290 there was a valid consistency with the values reported in the literature.

Stryjek, R. [Polish Academy of Sciences, Warsaw (Poland). Inst. of Physical Chemistry; Bobbo, S.; Camporese, R. [National Research Council, Padova (Italy). Inst. of Refrigeration Engineering

1998-03-01

344

Catalyst-assisted vapor-liquid-solid growth of single-crystal Ga2O3 nanobelts.  

PubMed

Mass production of quasi-one-dimensional gallium oxide nanobelts is accomplished through graphite-thermal reduction of a mixture of gallium oxide powders and SnO2 nanopowders under controlled experimental conditions. Sn nanoparticles are located at or close to the tips of the nanobelts and served as the catalyst for the nanobelt growth by a vapor-liquid-solid mechanism. The morphology and microstructure of the nanobelts were characterized by scanning electron microscopy and high-resolution transmission electron microscopy. The Ga2O3 nanobelts grow along the [104] direction, the widths ranged from several tens to several hundreds of nanometers, and the lengths ranged from several tens to several hundreds of micrometers. The growth of Ga2O3 nanobelts is initiated by Sn nanoparticles via a catalyst-assisted vapor-liquid-solid process, which makes it possible to control the sizes of Ga2O3 nanobelts. PMID:16852636

Zhang, Jun; Jiang, Feihong; Yang, Yongdong; Li, Jianping

2005-07-14

345

Vapor-liquid equilibria for the systems difluoromethane + hydrogen fluoride, dichlorodifluoromethane + hydrogen fluoride, and chlorine + hydrogen fluoride  

SciTech Connect

Isothermal vapor-liquid equilibria for difluoromethane + hydrogen fluoride, dichlorodifluoromethane + hydrogen fluoride, and chlorine + hydrogen fluoride have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. The binary system difluoromethane + hydrogen fluoride forms a homogeneous liquid phase, and the others form minimum boiling heterogeneous azeotropes at the experimental conditions.

Kang, Y.W. [KIST, Seoul (Korea, Republic of). Div. of Environmental and CFC Technology

1998-01-01

346

Vapor–liquid equilibria of LNG and gas condensate mixtures by the Nasrifar–Moshfeghian equation of state  

Microsoft Academic Search

The Nasrifar–Moshfeghian (NM) equation of state (EOS) is used to predict vapor–liquid equilibria (VLE) of multi-component mixtures. The systems under study consist of liquefied natural gases (LNG), gas condensates, an asymmetric system, slightly polar systems and gas\\/water systems. van der Waals mixing rules are used and no pure component parameter is adjusted; however, the predictions compare well with experimental data,

Kh Nasrifar; M Moshfeghian

2002-01-01

347

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

348

Laser absorption-scattering technique applied to asymmetric evaporating fuel sprays for simultaneous measurement of vapor\\/liquid mass distributions  

Microsoft Academic Search

This paper describes an Ultraviolet-Visible Laser Absorption-Scattering (UV-Vis LAS) imaging technique applied to asymmetric\\u000a fuel sprays. Continuing from the previous studies, the detailed measurement principle was derived. It is demonstrated that,\\u000a by means of this technique, cumulative masses and mass distributions of vapor\\/liquid phases can be quantitatively measured\\u000a no matter what shape the spray is. A systematic uncertainty analysis was

J. Gao; K. Nishida

2010-01-01

349

IMAGING OF VAPOR\\/LIQUID DISTRIBUTIONS OF SPLIT-INJECTED DIESEL SPRAYS IN A TWO-DIMENSIONAL MODEL COMBUSTION CHAMBER  

Microsoft Academic Search

The ultraviolet-visible laser absorption-scattering (LAS) technique was extended to simultaneous imaging of two-dimensional vapor\\/liquid mass distributions in a nonaxisymmetric evaporating diesel spray such as that injected into a two-dimensional model combustion chamber of direct-injection diesel engines. The main error for vapor measurement is incurred by the temperature dependence of molar absorption coefficients (TDMAC) of the test fuel. Thus, selecting a

YUYIN ZHANG; KEIYA NISHIDA

2004-01-01

350

Air stripping of volatile organic compounds from groundwater: An evaluation of a centrifugal vapor-liquid contractor  

SciTech Connect

The performance of a centrifugal vapor-liquid contactor equipped with high specific surface area packing (>2,000 m{sup 2}/m{sup 3}) was evaluated for air stripping of jet fuel components from groundwater. Hydraulic test data indicated that the Sherwood flooding correlation which has been proposed for use in designing centrifugal vapor-liquid contactors overestimates the rotational speeds at which flooding occurs. For the mass transfer performance, a concept of area of a transfer unit (ATU) was introduced to account for the change in fluid loading with radius of the packing torus. The ATU was found to be a strong function of the specific surface area of the packing and to a lesser extent a function of rotor speed and liquid flow rate. A correlation based on the specific surface area of the packing is proposed for predicting the ATU. A simple empirical model is also proposed for determining the power consumed in turning the packing torus at various operating conditions. Previous claims in the literature that centrifugal vapor-liquid contactor is resistant to fouling because of high shear force were found not to be valid for groundwater with high iron content.

Singh, S.P.

1989-01-01

351

Phase-equilibrium data requirements for cryogenic CO/sub 2/ recovery plant design  

SciTech Connect

The design and operation of CO/sub 2/ fractionation processes for enhanced oil recovery (EOR) applications is discussed. The analyses of CO/sub 2/-rich mixtures have shown the importance of interaction parameters and the inaccuracies of heavier-hydrocarbon K-values. The shortage of binary vapor-liquid equilibrium (VLE) data at subambient temperatures hinders further improvements in physical property correlations. If solvent injection is inevitable in the design, its effect on vapor-liquid, solid-liquid-vapor, and even liquid (1)-liquid (2)-vapor equilibria requires further experimental investigation. Based on new experimental information, the design margin can be estimated from a complete evaluation of correlations.

Yao, J.; Golikeri, S.V.; Chen, R.J.J.; Elliot, D.G.

1983-12-01

352

Isobaric mass systematics for A< or =60  

SciTech Connect

The isobaric multiplet mass equation and existing spectroscopic information have been used to establish systematics for E/sub C//sup(/sup 1/) and E/sub C//sup(/sup 2/) of the nuclear Coulomb energy and extend the concept of isobaric multiplets in a coherent manner up to A = 60. Collateral information on masses of T/sub z/ = -1,-2 nuclei and radii is also presented.

Antony, M.S.; Pape, A.

1984-10-01

353

Vapor-liquid-solid growth of Si nanowires: A kinetic analysis  

NASA Astrophysics Data System (ADS)

A steady state kinetic model has been developed for the vapor-liquid-solid growth of Si whiskers or nanowires from liquid catalyst droplets. The steady state is defined as one in which the net injection rate of Si into the droplet is equal to the ejection rate due to wire growth. Expressions that represent specific mechanisms of injection and ejection of Si atoms from the liquid catalyst droplet have been used and their relative importance has been discussed. The analysis shows that evaporation and reverse reaction rates need to be invoked, apart from just surface cracking of the precursor, in order to make the growth rate radius dependent. When these pathways can be neglected, the growth rate become radius independent and can be used to determine the activation energies for the rate limiting step of heterogeneous precursor decomposition. The ejection rates depend on the mechanism of wire growth at the liquid-solid interface or the liquid-solid-vapor triple phase boundary. It is shown that when wire growth is by nucleation and motion of ledges, a radius dependence of growth rate does not just come from the Gibbs-Thompson effect on supersaturation in the liquid, but also from the dependence of the actual area or length available for nucleation. Growth rates have been calculated using the framework of equations developed and compared with experimental results. The agreement in trends is found to be excellent. The same framework of equations has also been used to account for the diverse pressure and temperature dependence of growth rates reported in the literature.

Shakthivel, Dhayalan; Raghavan, Srinivasan

2012-07-01

354

Correlation of Zeno (Z = 1) line for supercritical fluids with vapor-liquid rectilinear diameters  

SciTech Connect

For a wide range of substances, extending well beyond the regime of corresponding states behavior, the contour in the temperature-density plane along which the compressibility factor Z = P/{rho}kT is the same as for an ideal gas is nearly linear. This Z = 1 contour, termed the Zeno line, begins deep in the liquid region and ascends as the density decreases to the Boyle point of the supercritical fluid, specified by the temperature T{sub B} for which (dZ/d{rho}){sub T} = 0 as {rho} {r_arrow} 0; equivalent, at T{sub B} the second virial coefficient vanishes. The slope of the Z = 1 line is {minus}B{sub 3}/(dB{sub 2}/dT), in terms of the third virial coefficient and the derivative of the second, evaluated at T{sub B}. Previous work has examined the Zeno line as a means to extend corresponding states and to enhance other practical approximations. Here the authors call attention to another striking aspect, a strong correlation with the line of rectilinear diameters defined by the average of the subcritical vapor and liquid densities. This correlation is obeyed well by empirical data for many substances and computer simulations for a Lennard-jones potential; the ratios of the intercepts and slopes for the Zeno and rectilinear diameter liens are remarkably close to those predicted by the van der Waals equation, 8/9 and 16/9, respectively. Properties of the slightly imperfect fluid far above the critical point thus implicitly determine the diameter of the vapor-liquid coexistence curve below the critical point.

Ben-Amotz, D.; Herschbach, D.R. [Exxon Research and Engineering Co., Annandale, NJ (United States). Corporate Research Science Lab.

1996-08-01

355

Vapor-liquid equilibria for copolymer+solvent systems: Effect of intramolecular repulsion  

SciTech Connect

Role of intramolecular interactions in blend miscibility is well documented for polymer+copolymer mixtures. Some copolymer+polymer mixtures are miscible although their corresponding homopolymers are not miscible; for example, over a range of acrylonitrile content, styrene/acrylonitrile copolymers are miscible with poly(methyl methacrylate) but neither polystyrene nor polyacrylonitrile is miscible with poly(methyl methacrylate). Similarly, over a composition range, butadiene/acrylonitrile copolymers are miscible with poly(vinyl chloride) while none of the binary combinations of the homopolymers [polybutadiene, polyacrylonitrile, and poly(vinyl chloride)] are miscible. This behavior has been attributed to ``intramolecular repulsion`` between unlike copolymer segments. We have observed similar behavior in vapor-liquid equilibria (VLE) of copolymer+solvent systems. We find that acrylonitrile/butadiene copolymers have higher affinity for acetonitrile solvent than do polyacrylonitrile or polybutadiene. We attribute this non-intuitive behavior to ``intramolecular repulsion`` between unlike segments of the copolymer. This repulsive interaction is weakened when acetonitrile molecules are in the vicinity of unlike copolymer segments, favoring copolymer+solvent miscibility. We find similar behavior when acetonitrile is replaced by methyl ethyl ketone. To best knowledge, this effect has not been reported previously for VLE. We have obtained VLE data for mixtures containing a solvent and a copolymer as a function of copolymer composition. It appears that, at a given solvent partial pressure, there may be copolymer composition that yields maximum absorption of the solvent. This highly non-ideal VLE phase behavior may be useful for optimum design of a membrane for a separation process.

Gupta, R.B.; Prausnitz, J.M.

1995-03-01

356

Nonequilibrium kinetic boundary condition at the vapor-liquid interface of argon  

NASA Astrophysics Data System (ADS)

A boundary condition for the Boltzmann equation (kinetic boundary condition, KBC) at the vapor-liquid interface of argon is constructed with the help of molecular dynamics (MD) simulations. The KBC is examined at a constant liquid temperature of 85 K in a wide range of nonequilibrium states of vapor. The present investigation is an extension of a previous one by Ishiyama, Yano, and Fujikawa [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.95.084504 95, 084504 (2005)] and provides a more complete form of the KBC. The present KBC includes a thermal accommodation coefficient in addition to evaporation and condensation coefficients, and these coefficients are determined in MD simulations uniquely. The thermal accommodation coefficient shows an anisotropic behavior at the interface for molecular velocities normal versus tangential to the interface. It is also found that the evaporation and condensation coefficients are almost constant in a fairly wide range of nonequilibrium states. The thermal accommodation coefficient of the normal velocity component is almost unity, while that of the tangential component shows a decreasing function of the density of vapor incident on the interface, indicating that the tangential velocity distribution of molecules leaving the interface into the vapor phase may deviate from the tangential parts of the Maxwell velocity distribution at the liquid temperature. A mechanism for the deviation of the KBC from the isotropic Maxwell KBC at the liquid temperature is discussed in terms of anisotropic energy relaxation at the interface. The liquid-temperature dependence of the present KBC is also discussed.

Ishiyama, Tatsuya; Fujikawa, Shigeo; Kurz, Thomas; Lauterborn, Werner

2013-10-01

357

Vapor-liquid equilibria of the binary systems nitrogen + bromotrifluoromethane, + bromochlorodifluoromethane, + 1,1,1,2,3,3,3-heptafluoropropane, and + trifluoroiodomethane from 293.2 to 313.2 K and 30 to 100 bar  

SciTech Connect

Bromotrifluoromethane (halon-1301) and bromochlorodifluoromethane (halon-1211) have been used as clean, nontoxic, and effective fire extinguishing agents for a long time. But these compounds are being phased out because of their ozone-depletion potential. Isothermal vapor-liquid equilibria were measured in the binary systems nitrogen + bromotrifluoromethane, nitrogen + bromochlorodifluoromethane, nitrogen + 1,1,1,2,3,3,3-heptafluoropropane, and nitrogen + trifluoroiodomethane in a circulation-type equilibrium apparatus. The temperature range was (293.2 to 313.2) K and the pressure range was (30 to 100) bar. The experimental data were well correlated with the Peng-Robinson equation of state using the Wong and Sandler mixing rule, and the relevant parameters are presented.

Lim, J.S.; Kim, J.D. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Div. of Environmental and CFC Technology

1997-01-01

358

Synthesis and characterization of group IV semiconductor nanowires by vapor-liquid-solid growth  

NASA Astrophysics Data System (ADS)

There is currently intense interest in one-dimensional nanostructures, such as nanotubes and nanowires, due to their potential to test fundamental concepts of dimensionality and to serve as building blocks for nanoscale devices. Vapor-liquid-solid (VLS) growth, which is one of the most common fabrication methods, has been used to produce single crystal semiconductor nanowires such as silicon (Si), germanium (Ge), and gallium arsenide (GaAs). In the VLS growth of Group IV semiconductor nanowires, a metal, such as gold (Au) is used as a catalyst agent to nucleate whisker growth from a Si-containing (silane (SIH4)) or Ge-containing vapor (germane (GeH 4)). Au and Si/Ge form a liquid alloy that has a eutectic temperature of around 360°C, which, upon supersaturation, nucleates the growth of a Si or Ge wire. The goal of this work is to develop a more fundamental understanding of VLS growth kinetics and intentional doping of Group IV semiconductor nanowires in order to better control the properties of the nanowires. The fabrication of p-type and n-type Si nanowires will be studied via the addition of dopant gases such as diborane (B2H 6), trimethylboron (TMB), and phosphine (PH3) during growth. The use of gaseous dopant sources provides more flexibility in growth, particularly for the fabrication of p-n junctions and structures with axial dopant variations (e.g. p+-p- p+). The study is then extended to fabricate SiGe alloy nanowires by mixing SiH4 and GeH4. Bandgap engineering in Si/SiGe heterostructures can lead to novel devices with improved performance compared to those made entirely of Si. The scientific findings will lead to a better understanding of the fabrication of Si/SiGe axial and radial heterostructure nanowires for functional nanowire device structures, such as heterojunction bipolar transistors (HBTs) and high electron mobility transistors (HEMTs). Eventually, the central theme of this research is to provide a scientific knowledge base and foundation for the design of Si, Ge, and SiGe nanostructures that will be of importance in nanoscale device applications.

Lew, Kok-Keong

359

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

360

Effect of cooling time on the vapor liquid solid based growth of gold-catalyzed bismuth nanorods  

NASA Astrophysics Data System (ADS)

Deposition of single crystalline bismuth nanorods (Bi NRs) using a thermal evaporation method through vapor-liquid-solid (VLS) mechanism is reported here and the effect of sample cooling time on the growth of Bi NRs is investigated. Deposited Bi NRs have diameters varying from 100 to 400 nm and lengths extending to ?3 ?m in the (012) growth direction. Morphological observation indicated that the length and density of Bi NRs are strongly coupled with prolonged cooling time. A growth mechanism is suggested and discussed to describe the growth of single crystalline Bi NRs based on the morphological observations as a function of cooling temperature and time.

Acharya, Susant Kumar; Rai, Alok Kumar; Kim, Gil-Sung; Hyung, Jung-Hwan; Ahn, Byung-Guk; Lee, Sang-Kwon

2012-01-01

361

Engineering scale development of the Vapor-Liquid-Solid (VLS) process for the production of silicon carbide fibrils  

SciTech Connect

Vapor-liquid-solid (VLS)SiC fibrils are used as reinforcement in ceramic matrix composites (CMC). A program has been completed for determining process scaleup parameters and to produce material for evaluation in a CMC. The scaleup is necessary to lower production cost and increase material availability. Scaleup parameters were evaluated in a reactor with a vertical dimension twice that of the LANL reactor. Results indicate that the scaleup will be possible. Feasibility of recycling process gas was demonstrated and the impact of postprocessing on yields determined.

Hollar, W.E. Jr. [Carborundum Co., Niagara Falls, NY (United States). Technology Div.; Mills, W.H. [BP America, Inc., Cleveland, OH (United States)

1993-09-01

362

Vapor-liquid equilibria of copolymer + solvent and homopolymer + solvent binaries: New experimental data and their correlation  

Microsoft Academic Search

Sixty-four isothermal data sets for vapor-liquid equilibria (VLE) for polymer + solvent binaries have been obtained using a gravimetric sorption technique, in the range of 23.5--80 C. Solvents studied were acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied were poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styrene-co-butadiene), poly(styrene-co-butyl methacrylate), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers were random

Ram B. Gupta; John M. Prausnitz

1995-01-01

363

Vertically Aligned InP Nanowires Grown via the Self-Assisted Vapor--Liquid--Solid Mode  

NASA Astrophysics Data System (ADS)

We have demonstrated the growth of vertical InP nanowires via the self-assisted vapor--liquid--solid mode on an InP(111) substrate. Single nanowires exhibit a highly uniform diameter along the axial direction despite their 15 ?m length. We show direct evidence of the self-assisted growth mode by performing a compositional analysis of the NW tip. We demonstrated that the In particle at the NW tip could be removed by modifying the V/III source material ratio during growth. Single InP nanowires exhibit a distinct TO phonon peak and show the luminescence of the excitonic emission at 4 K.

Zhang, Guoqiang; Tateno, Kouta; Gotoh, Hideki; Sogawa, Tetsuomi

2012-05-01

364

A DYNAMIC EQUILIBRIUM ANALYSIS OF A LEADING EDGE THERMAL HEAT SPREADER USING A CUBIC EQUATION OF STATE  

Microsoft Academic Search

A new thermodynamic model for calculating the steady state behavior of a leading edge thermal heat spreader, which operates upon the principles of evaporation, convection, and condensation of a working fluid, is presented. The intense, localized impinging heat flux is balanced with the thermal capacitance of the container walls and working fluid. The thermophysical properties of the vapor-liquid equilibrium are

Scott D. Kasen

365

The vapor-liquid interface potential of (multi)polar fluids and its influence on ion solvation  

NASA Astrophysics Data System (ADS)

The interface between the vapor and liquid phase of quadrupolar-dipolar fluids is the seat of an electric interfacial potential whose influence on ion solvation and distribution is not yet fully understood. To obtain further microscopic insight into water specificity we first present extensive classical molecular dynamics simulations of a series of model liquids with variable molecular quadrupole moments that interpolates between SPC/E water and a purely dipolar liquid. We then pinpoint the essential role played by the competing multipolar contributions to the vapor-liquid and the solute-liquid interface potentials in determining an important ion-specific direct electrostatic contribution to the ionic solvation free energy for SPC/E water--dominated by the quadrupolar and dipolar parts--beyond the dominant polarization one. Our results show that the influence of the vapor-liquid interfacial potential on ion solvation is strongly reduced due to the strong partial cancellation brought about by the competing solute-liquid interface potential.

Horváth, Lorand; Beu, Titus; Manghi, Manoel; Palmeri, John

2013-04-01

366

Isobaric identification techniques of AMS at CIAE  

NASA Astrophysics Data System (ADS)

Some long-lived nuclides, such as 36Cl, 41Ca, 53Mn, 79Se, etc., are very interested in life science, environment science, geo- and cosmo-sciences, nuclear wastes management, and other fields. Taking the advantages in high sensitivity and the strong ability to reduce the interferences from molecular ions and isobars, AMS has been one of the most promising methods for the measurement of these nuclides. However, the sensitivity of AMS is often unsatisfactory due to the interferences of stable isobars especially for medium and heavy radioisotopes. Gas-filled time of flight (GF-TOF), Gas-filled Magnet with a time of flight (GFM-TOF), Bragg Curve detector and energy loss (?E) combined with a Q3D magnetic spectrometer (?E-Q3D) are among the techniques used or being developed in AMS lab of China Institute of Atomic Energy, in an attempt to further reduce the interferences from isobars. These techniques will be tested in our AMS measurement of 53Mn, 79Se, 93Zr, 99Tc, etc., for identifying isobaric interferences.

Li, Chaoli; Guan, Yongjing; Jiang, Shan; He, Ming; Ruan, Xiangdong; Wang, Wei; Zhang, Dawei; Yuan, Jian; Wu, Shaoyong; Dong, Kejun

2010-04-01

367

Isobaric Analog States in CL35.  

National Technical Information Service (NTIS)

The gamma-ray yield from the S34(p, gamma)Cl35 reaction shows strong resonances at proton energies of 1214 and 1512 keV. These resonance states occur at the correct energies to be isobaric analogs of the 1.99- and 2.35-MeV states in S35, respectively. Ang...

D. D. Watson J. C. Manthuruthil F. D. Lee

1968-01-01

368

Fine Structure of Isobaric Analog States.  

National Technical Information Service (NTIS)

The split isobaric analog states arising in medium-heavy nuclei were analized in (p, gamma ) reactions using differential excitation functions. The spin and parity of the states on the gsub(9/2) shell model orbit were determined from angular distributions...

I. Fodor

1980-01-01

369

Vapor–liquid equilibria of alternative refrigerants and their binaries by molecular simulations employing the reaction Gibbs ensemble Monte Carlo method  

Microsoft Academic Search

Alternative refrigerants HFC125 (CHF2CF3) and HFC 134a (CF3CH2F) are modeled as a dipolar two-center Lennard–Jones fluid and alternative refrigerant HFC32 (CH2F2) is modeled as a dipolar Lennard–Jones fluid. We calculate vapor–liquid equilibria of these refrigerants by Gibbs–Duhem integration and vapor–liquid equilibria of two binaries (HFC 125 + HFC 134a and HFC 134a + HFC 32) by the reaction Gibbs ensemble

R. Budinský; V. Vacek; M. L??sal

2004-01-01

370

Phase equilibrium of liquid mixtures: Experimental and modeled data using statistical associating fluid theory for potential of variable range approach  

Microsoft Academic Search

A study of the phase equilibrium (experimental and modeled) of mixtures formed by a cyclic ether and haloalkanes has been derived. Experimental data for the isothermal vapor liquid equilibrium of mixtures formed by tetrahydrofuran and tetrahydropyran and isomeric chlorobutanes at temperatures of 298.15, 313.15, and 328.15 K are presented. Experimental results have been discussed in terms of both molecular characteristics

Beatriz Giner; Isabel Bandrés; M. Carmen López; Carlos Lafuente; Amparo Galindo

2007-01-01

371

The effect of a uniform electric field on homogeneous vapor-liquid nucleation in a dipolar fluid. I. Stockmayer fluid  

NASA Astrophysics Data System (ADS)

The rate of homogeneous vapor-liquid nucleation is controlled mainly by the Gibbs formation free energy of critical clusters. Within the framework of the i/v cluster theory of Reiss and co-workers, the formation free energies of Stockmayer clusters in the presence of a uniform electric field are determined. The Helmholtz free energy of the clusters, an input required in the i/v cluster theory, is calculated via Monte Carlo simulations. The most significant result is that as a uniform electric field is applied the formation free energy at fixed supersaturation of the vapor becomes larger than that in the absence of a field, whereas at fixed chemical potential the formation free energy becomes smaller.

Oh, K. J.; Gao, G. T.; Zeng, X. C.

1998-11-01

372

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

373

Subcontracted R and D Final Report: SRC-I Phase Equilibrium and Enthalpy Data for Coal Liquefaction and Solvent Recovery Areas. Volume 1.  

National Technical Information Service (NTIS)

International Coal Refining Company instituted a 2-year program to develop new data on SRC-I coal liquids and related model compounds. Specifically, the overall program obtectives were to develop vapor/liquid equilibrium (VLE) and enthalpy data to modify ...

D. C. Mehta I. C. Chu

1984-01-01

374

Comparison of high-pressure vapor-liquid equilibria of mixtures of CO{sub 2} or propane with nonane and C{sub 9} alkylbenzenes  

SciTech Connect

Vapor-liquid equilibria were measured for (1) binary mixtures of carbon dioxide with nonane, cumene, propylbenzene, or mesitylene, (2) binary mixtures of propane with nonane, cumene, or mesitylene, and (3) ternary mixtures of carbon dioxide, nonane, and cumene. For the carbon dioxide mixtures, vapor-liquid equilibria were measured at 70 C and at pressures ranging from 3.7 MPa to 12.1 MPa. For the propane mixtures, vapor-liquid equilibria were measured at 104 C and at pressures ranging from 0.9 MPa to 3.7 MPa. It was found that differences in the phase equilibria of the mixtures could be explained primarily by the self-association of the C{sub 9} components. The composition of the C{sub 9} components in the vapor phase compositions were found to be directly related to the volatility (self-association) of the C{sub 9} component. Liquid phase compositions were found to be enriched in carbon dioxide or propane content in the mixtures containing C{sub 9} compounds having the weakest self-association. Also presented in this paper are comparisons of measurements of vapor-liquid equilibria of carbon dioxide + decane and propane + decane with literature data as validation of the two experimental methods used. These measurements were made at 71 C for the carbon dioxide + decane mixtures and at temperatures ranging from 38 C to 120 C for the propane + decane mixtures.

Jennings, D.W.; Schucker, R.C. [Exxon Research and Development Labs., Baton Rouge, LA (United States)

1996-07-01

375

Sea-Level Pressure: Contouring Isobars  

NSDL National Science Digital Library

This interactive feature shows how an isobar (atmospheric pressure) map is drawn. Students can select an individual contour value and watch as the animation correctly places the line with respect to pressure values on the map. The animation also marks high and low pressure systems, toggles between coded (station model) and decoded pressure values, and permits the user to color the spaces between the contour lines on the map.

376

Theoretical study of vapor-liquid homogeneous nucleation using stability analysis of a macroscopic phase.  

PubMed

Stability analysis is generally used to verify that the solution to phase equilibrium calculations corresponds to a stable state (minimum of the free energy). In this work, tangent plane distance analysis for stability of macroscopic mixtures is also used for analyzing the nucleation process, reconciling thus this analysis with classical nucleation theories. In the context of the revised nucleation theory, the driving force and the nucleation work are expressed as a function of the Lagrange multiplier corresponding to the mole fraction constraint from the minimization problem of stability analysis. Using a van der Waals fluid applied to a ternary mixture, Lagrange multiplier properties are illustrated. In particular, it is shown how the Lagrange multiplier value is equal to one on the binodal and spinodal curves at the same time as the driving force of nucleation vanishes on these curves. Finally, it is shown that, on the spinodal curve, the nucleation work from the revised and generalized nucleation theories are characterized by two different local minima from stability analysis, irrespective of any interfacial tension models. PMID:23061836

Carreón-Calderón, Bernardo

2012-10-14

377

Use of phosphine as an n-type dopant source for vapor-liquid-solid growth of silicon nanowires.  

PubMed

Phosphine (PH3) was investigated as an n-type dopant source for Au-catalyzed vapor-liquid-solid (VLS) growth of phosphorus-doped silicon nanowires (SiNWs). Transmission electron microscopy characterization revealed that the as-grown SiNWs were predominately single crystal even at high phosphorus concentrations. Four-point resistance and gate-dependent conductance measurements confirmed that electrically active phosphorus was incorporated into the SiNWs during VLS growth. A transition was observed from p-type conduction for nominally undoped SiNWs to n-type conduction upon the introduction of PH3 to the inlet gas. The resistivity of the n-type SiNWs decreased by approximately 3 orders of magnitude as the inlet PH3 to silane (SiH4) gas ratio was increased from 2 x 10(-5) to 2 x 10(-3). These results demonstrate that PH3 can be used to produce n-type SiNWs with properties that are suitable for electronic and optoelectronic device applications. PMID:16277441

Wang, Yanfeng; Lew, Kok-Keong; Ho, Tsung-Ta; Pan, Ling; Novak, Steven W; Dickey, Elizabeth C; Redwing, Joan M; Mayer, Theresa S

2005-11-01

378

A density functional theory for vapor-liquid interfaces using the PCP-SAFT equation of state  

NASA Astrophysics Data System (ADS)

A Helmholtz energy functional for inhomogeneous fluid phases based on the perturbed-chain polar statistical associating fluid theory (PCP-SAFT) equation of state is proposed. The model is supplemented with a capillary wave contribution to the surface tension to account for long-wavelength fluctuations of a vapor-liquid interface. The functional for the dispersive attraction is based on a nonlocal perturbation theory for chain fluids and the difference of the perturbation theory to the dispersion term of the PCP-SAFT equation of state is treated with a local density approximation. This approach suggested by Gloor et al. [Fluid Phase Equilib. 194, 521 (2002)] leads to full compatibility with the PCP-SAFT equation of state. Several levels of approximation are compared for the nonlocal functional of the dispersive attractions. A first-order non-mean-field description is found to be superior to a mean-field treatment, whereas the inclusion of a second-order perturbation term does not contribute significantly to the results. The proposed functional gives excellent results for the surface tension of nonpolar or only moderately polar fluids, such as alkanes, aromatic substances, ethers, and ethanoates. A local density approximation for the polar interactions is sufficient for carbon dioxide as a strongly quadrupolar compound. The surface tension of acetone, as an archetype dipolar fluid, is overestimated, suggesting that a nonisotropic orientational distribution function across an interface should for strong dipolar substances be accounted for.

Gross, Joachim

2009-11-01

379

Vapor-liquid equilibria for difluoromethane (R32) + and pentafluoroethane (R125) + 1,1,1,3,3,3-hexafluoropropane (R236fa) at 303.2 and 323.3 K  

SciTech Connect

Isothermal vapor-liquid equilibria (VLE) for the binary systems difluoromethane (R32) + 1,1,1,3,3,3-hexafluoropropane (R236fa) and pentafluoroethane (R125) + 1,1,1,3,3,3-hexafluoropropane (R236f) were measured at 303.2 and 323.3 K using a recirculation apparatus in which the vapor phase was forced through the liquid. The phase composition at equilibrium was measured by gas chromatography, calibrating its response using gravimetrically prepared mixtures. Both systems show a slight deviation from Raoult`s law. The data were reduced by the Carnahan-Starling-De Santis EOS. The deviations observed in vapor composition, averaging below 0.003 in mole fraction, confirm the consistency of the experimental findings and the model used for their reduction. Calculated excess Gibbs energy functions reveal values to be within {+-}40 J/mol at T = 303 K. The margins of error in pressure, temperature, and composition of vapor and liquid-phase measurements were estimated to be less than {+-}0.15%, {+-}0.005 K, and {+-}0.0015 of mole fraction, respectively.

Bobbo, S.; Camporese, R. [National Research Council, Padova (Italy). Inst. of Refrigeration; Stryjek, R. [Polish Academy of Sciences, Warsaw (Poland). Inst. of Physical Chemistry

1999-03-01

380

Vapor-liquid equilibria in the nitrogen + carbon dioxide + propane system from 240 to 330 K at pressures to 15 MPa  

SciTech Connect

The design and development of separation processes in the natural gas industry requires accurate knowledge of the vapor-liquid equilibria of multicomponent systems consisting of the alkane hydrocarbons with carbon dioxide and nitrogen. Vapor-liquid equilibria were measured for the nitrogen, carbon dioxide, and propane ternary system and its constituent binaries over the temperature range 240 K to 330 K. The binary systems were measured at 240, 270, and 330 K, and the ternary system was studied at 240 K for 2.0 and 13.0 MPa, 270 K for 2.0, 6,0, and 13.0 MPa, and 330 K and 5 MPa. The Peng-Robinson equation of state was used to model the system.

Yucelen, B.; Kidnay, A.J. [Colorado School of Mines, Golden, CO (United States). Dept. of Chemical Engineering and Petroleum-Refining

1999-09-01

381

Isobar Selective Laser Photodetachment In Trace Element Analysis  

SciTech Connect

We are investigating the possibility to use laser photodetachment of negative ions as an isobaric selective filter in accelerator mass spectrometry (AMS). If successful, this method can be used to obtain higher sensitivity realized through better selectivity by suppression of molecular and/or elemental isobaric interference in different investigations using ultra rare isotopes in the 10{sup -13} range and below.

Andersson, P.; Hanstorp, D.; Lindahl, A. O. [Department of Physics, University of Gothenburg, SE-412 96 Gothenburg (Sweden); Forstner, O. [VERA-Laboratory, Faculty of Physics, University of Vienna, Kavalierstrakt A-1090 Wien (Austria); Wendt, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet, Mainz, D-55099 Mainz (Germany)

2009-03-17

382

Isothermal vapor-liquid equilibria for the systems 1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride  

SciTech Connect

Isothermal vapor-liquid equilibria for the three binary systems (1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride) have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. All of the systems form minimum boiling heterogeneous azeotropes.

Kang, Y.W.; Lee, Y.Y. [KIST, Seoul (Korea, Republic of)

1997-03-01

383

Isothermal vapor-liquid equilibria for the systems 1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride  

Microsoft Academic Search

Isothermal vapor-liquid equilibria for the three binary systems (1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride) have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. All of the systems form minimum

Yun Whan Kang; Youn Yong Lee

1997-01-01

384

Representation of vapor-liquid and liquid-liquid equilibria for binary systems containing polymers: Applicability of an extended Flory-Huggins equation  

Microsoft Academic Search

For some binary systems, an extended Flory-Huggins equation is applicable to both vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) using the same adjustable parameters. New LLE and VLE data are reported for polystyrene (PS) (MW = 100,000)\\/ cyclohexane and for poly(ethylene glycol) (PEG) (MW = 8,000)\\/water. Experimental results for the PS\\/cyclohexane system agree well with the semiempirical model, whereas those

Y. C. Bae; J. J. Shim; D. S. Soane; J. M. Prausnitz

1993-01-01

385

Vapor-liquid equilibria for coal liquids by gas chromatography. Final report for 1983/84 SOMED project  

SciTech Connect

Successful design of refineries and chemical plants requires accurate calculation of vapor-liquid equilibria (VLE). With advances in computing power these calculations are increasingly being done by the equation of state (EOS) method. However, the interaction parameters for these EOS must be based on experimental data. Decades of work have produced an extensive data base for paraffinic hydrocarbons. No such data base exists for aromatic, condensed ring compounds characteristic of synfuels and syncrudes from direct liquefaction processes on hydrogen deficient materials such as coal and Eastern oil shale. The work done in this study involves measuring activity coefficients at infinite dilution for hydrocarbons and other compounds in an aromatic material such as fluorene. Activity coefficients at infinite dilution are an optimum source of VLE data because solution effects are usually at a maximum at infinite dilution. An existing gas chromatograph has been extensively modified and tested to insure that reproducible infinite dilution activity coefficients can be obtained over a wide range of chromatographic operating conditions. Measurements of infinite dilution activity coefficients have been made for the standard system hexane and hexadecane and for the systems octane and fluorene and toluene and fluorene. Our measured test system value checks well with the accepted value from the literature. The results have been correlated with the Soave modification of the Redlich-Kwong EOS (RKS EOS). Determination of a binary interaction parameter allows the RKS EOS to represent the activity coefficient with little error. Measurements are being made on additional systems at the present and there are plans to test other EOS. 7 references, 4 figures, 4 tables.

Arnold, D.W.; Juang, M.; Morgan, K.

1984-11-01

386

Isobar Separators for Radioactive Ion Beam Facilities  

SciTech Connect

A radioactive ion beam facility - in short a RIB facility - produces ions of short-lived nuclei and accelerates them to energies of 0.1?10 MeV per nucleon or even higher. In this process it is important that the resulting RIB beams are free from nuclei of neighboring isobars or of neighboring elements. This task requires the production and ionization of the nuclei of interest as well as separating them from all others with a high-mass resolving power and small-mass cross contaminations. When constructing such a facility it also is very important to find ways that allow the accelerated ions to be provided to different experiments at least quasi simultaneously.

Garrett, J.D.; Wollnik, H.

1998-10-05

387

Phase equilibrium modeling of mixtures of long-chain and short-chain alkanes using Peng–Robinson and SAFT  

Microsoft Academic Search

Peng–Robinson and selected implementations of the Statistical Associating Fluid Theory (SAFT) equation of state (EoS) were evaluated for their ability to correlate and predict vapor–liquid equilibrium for highly asymmetric mixtures of n-alkanes. Peng–Robinson is surprisingly accurate for fitting such mixtures, but only if the pure component parameters are regressed with vapor pressure and liquid density data, as is normally done

P. David Ting; Patrick C. Joyce; Prasanna K. Jog; Walter G. Chapman; Mark C. Thies

2003-01-01

388

Monte Carlo simulations in generalized isobaric-isothermal ensembles.  

PubMed

We present three generalized isobaric-isothermal ensemble Monte Carlo algorithms, which we refer to as the multibaric-multithermal, multibaric-isothermal, and isobaric-multithermal algorithms. These Monte Carlo simulations perform random walks widely in volume space and/or in potential energy space. From only one simulation run, one can calculate isobaric-isothermal-ensemble averages in wide ranges of pressure and temperature. We demonstrate the effectiveness of these algorithms by applying them to the Lennard-Jones 12-6 potential system with 500 particles. PMID:15447615

Okumura, Hisashi; Okamoto, Yuko

2004-08-13

389

Phase equilibrium measurements on twelve binary mixtures  

SciTech Connect

Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin; methanol + hydrogen cyanide. For these systems, equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson, NRTL, or Redlich-Kister activity coefficient model to represent the liquid phase. The infinite dilution activity coefficient of methylamine in N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone-rich half of the binary. Liquid-liquid equilibrium studies were made on the triethylene glycol + 1-pentene system at two temperatures by directly analyzing samples taken from each liquid phase.

Giles, N.F. [Wiltec Research Co., Inc., Provo, UT (United States); Wilson, H.L.; Wilding, W.V. [Brigham Young Univ., Provo, UT (United States). Chemical Engineering Dept.

1996-11-01

390

Wavelength limits on isobaricity of perturbations in a thermally unstable radiatively cooling medium  

NASA Astrophysics Data System (ADS)

Nonlinear evolution of one-dimensional planar perturbations in an optically thin, radiatively cooling medium in the long-wavelength limit is studied numerically. The accepted cooling function generates, in thermal equilibrium, a bistable equation of state P(?). The unperturbed state is taken close to the upper (low-density) unstable state with infinite compressibility (dP/d?=0). The evolution is shown to proceed in three different stages. At the first stage, pressure and density set in the equilibrium equation of state, and velocity profile steepens gradually, as in the case of pressure-free flows. At the second stage, those regions of the flow where anomalous pressure (i.e., with negative compressibility) holds create a velocity profile sharper than in the pressure-free case, which in turn results in formation of a very narrow (short-wavelength) region where gas separates the equilibrium equation of state and pressure equilibrium sets in rapidly. At this stage, the variation in pressure between the narrow dense region and the extended environment does not exceed more than 0.01 of the unperturbed value. At the third stage, gas in the short-wavelength region reaches the second (high-density) stable state, and pressure balance establishes through the flow, with pressure equal to the one in the unperturbed state. In external (long-wavelength) regions, gas forms slow isobaric inflow toward the short-wavelength layer. The duration of these stages decreases when the ratio of the acoustic time to the radiative cooling time increases. The limits in which nonlinear evolution of thermally unstable long-wavelength perturbations develops in isobaric regime are obtained.

Kovalenko, I. G.; Shchekinov, Yu. A.

1999-01-01

391

High-pressure vapor–liquid equilibrium of binary systems with R236fa 1 Paper presented at the 5th Asian Thermophysical Properties Conference. 1  

Microsoft Academic Search

Within the European Union Joule project aimed at the substitution of R114 in high temperature heat pumps with chlorine-free, environmentally benign fluids, R236fa has been chosen as one of the components of mixtures to consider as alternative fluids for R114 (1,2-dichlorotetrafluoroethane). The results of VLE measurements performed at our laboratory on mixtures including R236fa are summarized and discussed for the

Sergio Bobbo; Roberto Camporese; Roman Stryjek

1999-01-01

392

Evaluation of the Decay Characteristics of Isobars with A=95.  

National Technical Information Service (NTIS)

Energies and intensities of the beta transitions, gamma photons and conversion electrons accompanying beta decay and electron capture, internal conversion coefficients, energy levels and lifetimes of the ground and excited states of isobars with A=95 are ...

Y. I. Grigor'yan L. L. Sokolovskii F. E. Chukreev E. N. Shurshikov

1978-01-01

393

SWRO Membrane Design with Isobaric Energy Recovery Devices Authors  

Microsoft Academic Search

The great majority of medium and large seawater reverse osmosis (SWRO) desalination plants being designed and built today use isobaric energy recovery devices (ERDs) to minimize energy consumption. Isobaric ERDs transfer pressure from the high-pressure concentrate reject from the SWRO membranes to low-pressure seawater by placing the streams into contact in pressure-equilibrating chambers. This positive-displacement mechanism provides high hydraulic transfer

Richard L. Stover; Andreas Gorenflo

394

Molecular dynamics study of the effect of calcium ions on the monolayer of SDC and SDSn surfactants at the vapor/liquid interface.  

PubMed

The effect of Ca(2+) ions on the hydration shell of sodium dodecyl carboxylate (SDC) and sodium dodecyl sulfonate (SDSn) monolayer at vapor/liquid interfaces was studied using molecular dynamics simulations. For each surfactant, two different surface concentrations were used to perform the simulations, and the aggregation morphologies and structural details have been reported. The results showed that the aggregation structures relate to both the surface coverage and the calcium ions. The divalent ions can screen the interaction between the polar head and Na(+) ions. Thus, Ca(2+) ions locate near the vapor/liquid interface to bind to the headgroup, making the aggregations much more compact via the salt bridge. The potential of mean force (PMF) between Ca(2+) and the headgroups shows that the interaction is decided by a stabilizing solvent-separated minimum in the PMF. To bind to the headgroup, Ca(2+) should overcome the energy barrier. Among contributions to the PMF, the major repulsive interaction was due to the rearrangement of the hydration shell after the calcium ions entered into the hydration shell of the headgroup. The PMFs between the headgroup and Ca(2+) in the SDSn systems showed higher energy barriers than those in the SDC systems. This result indicated that SDSn binds the divalent ions with more difficulty compared with SDC, so the ions have a strong effect on the hydration shell of SDC. That is why sulfonate surfactants have better efficiency in salt solutions with Ca(2+) ions for enhanced oil recovery. PMID:21495650

Yan, Hui; Guo, Xin-Li; Yuan, Shi-Ling; Liu, Cheng-Bu

2011-04-15

395

Shift of the velocity of low-frequency pressure perturbations in the vapor-liquid mixture under nonadiabatic conditions  

NASA Astrophysics Data System (ADS)

A theoretical study of the equilibrium velocity of sound in the liquid-vapor mixture containing the close-packed layer of spherical particles has been carried out. Thermodynamic relations include a description of a non-stationary heat transfer between the mixture and particles in compression half-wave. The theoretical model allows explaining the experimentally observed significant reduction in the equilibrium velocity from its adiabatic value at the increase in vapor content of the mixture. The calculated results agree with experimental data obtained in the vertical channel at filtering the liquid-vapor mixture in a close-packed layer of spherical particles of borosilicate glass and steel.

Tairov, E. A.

2013-09-01

396

Isobaric VLE data for the binary systems dibromomethane with isomeric butanols at 40.0 and 101.3 kPa  

Microsoft Academic Search

Isobaric vapour-liquid equilibrium data at 40.0 and 101.3 kPa for the binary systems dibromomethane with 1-butanol, 2-butanol, 2-methyl-1-propanol and 2-methyl-2-propanol are reported. All the systems show minimum temperature azeotropes. The experimental data were tested for thermodynamic consistency and correlated with the Margules, Van Laar, Wilson, NRTL and UNIQUAC equations. Predictions with the UNIFAC method were also obtained.

V. Rodríguez; C. Lafuente; J. Santafé; F. M. Royo; J. S. Urieta

1995-01-01

397

Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H sub 2 O and NaCl-H sub 2 O  

SciTech Connect

Measurements of isothermal vapor-liquid compositions for KCl-H{sub 2}O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H{sub 2}O, has been used for representation of the KCl-H{sub 2}O system from 300 to 410{degree}C. Improve parameters are also reported for NaCl-H{sub 2}O from 300 to 500{degree}C.

Hovey, J.K.; Pitzer, K.S.; Tanger, J.C. IV (Lawrence Berkeley Lab., CA (USA)); Bischoff, J.L.; Rosenbauer, R.J. (Geological Survey, Menlo Park, CA (USA))

1990-02-08

398

Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H2O and NaCl-H2O  

USGS Publications Warehouse

Measurements of isothermal vapor-liquid compositions for KCl-H2O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H2O, has been used for representation of the KCl-H2O system from 300 to 410??C. Improved parameters are also reported for NaCl-H2O from 300 to 500??C. ?? 1990 American Chemical Society.

Hovey, J. K.; Pitzer, K. S.; Tanger, IV, J. C.; Bischoff, J. L.; Rosenbauer, R. J.

1990-01-01

399

Isothermal-isobaric molecular dynamics simulations with Monte Carlo volume sampling  

NASA Astrophysics Data System (ADS)

A new pressure coupling method is described that combines Monte Carlo volume-space sampling with traditional molecular dynamics calculations to simulate the physical properties of molecular systems under standard conditions. The pressure is maintained by accepting or rejecting volume moves of newly propagated configurations using the Metropolis algorithm with probability P ( V ) = min(1, exp(( - 1/ kT 0 ){ E + P 0 V - NkT 0 1n[( V + V )/ V ]})). The sample is further coupled to an external temperature bath using a variation of Andersen's stochastic collisions. The computational approach was implemented and applied to simulate the equilibrium properties of dense neon at various pressures. The results show the method to be both reliable and efficient for maintaining isothermal-isobaric conditions and should prove effective for studying the pressure dependence of physical properties in molecular systems.

Kim-Hung, Chow; Ferguson, David M.

1995-09-01

400

Vapor-liquid equilibria for nitric acid-water and plutonium nitrate-nitric acid-water solutions  

Microsoft Academic Search

The liquid-vapor equilibrium data for nitric acid and nitric acid-plutnonium nitrate-water solutions were examined to develop correlations covering the range of conditions encountered in nuclear fuel reprocessing. The scanty available data for plutonium nitrate solutions are of poor quality but allow an order of magnitude estimate to be made. A formal thermodynamic analysis was attempted initially but was not successful

Maimoni

1980-01-01

401

Shear viscosity and thermal conductivity of dipolar real fluids from equilibrium molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

Equilibrium molecular dynamics and the Green Kubo formalism were used to simultaneously calculate shear viscosity and thermal conductivity for 10 refrigerants: R11, R12, R22, R23, R41, R123, R134a, R142b, R143a, and R152a. The fluids were modelled in previous work of Stoll et al. [J Chem Phys 2003;119:11396 407] using the two-center Lennard Jones plus point dipole (2CLJD) pair potential, with parameters adjusted to vapor liquid equilibria only. The predicted shear viscosities and thermal conductivities show an overall average deviation of about 15% and 10%, respectively, from correlations of experimental data.

Fernández, Gimmy A.; Vrabec, Jadran; Hasse, Hans

2006-10-01

402

Calculation of NARM's equilibrium with Peng-Robinson equation of state  

NASA Astrophysics Data System (ADS)

The liquid molar volumes of nonazeotropic refrigerant mixtures (NARM), calculated with Peng Robinson (PR) equation, were compared with vapor -liquid equilibrium experimental data in this paper. Provided with co-reaction coefficient k ij , the discrepancies of liquid molar volume data for R22+R114 and R22+R142b using PR equation are 7.7% and 8.1%, respectively. When HBT (Hankinson-Brobst-Thomson) equation was joined with PR equation, the deviations are reduced to less than 1.5% for both R22+R114 and R22+R142b.

Li, Tingxun; Guo, Kaihua; Wang, Ruzhu; Fan, Shuanshi

2001-04-01

403

A time-resolved numerical study of the vapor-liquid-solid growth kinetics describing the initial nucleation phase as well as pulsed deposition processes.  

PubMed

Today, the vapor-liquid-solid (VLS) growth mechanism is a common process for the metal catalyzed bottom-up growth of semiconductor nanowires (NWs). Nevertheless, most of the literature only is concerned with the steady-state NW growth which applies when the amount of material supplied is equal to the amount consumed by the NW growth at the same time. While this description is suitable for chemical vapor deposition (CVD) or electron beam evaporation (EBE) processes after the initial nucleation time, problems arise when pulsed growth processes like pulsed laser deposition (PLD) are used since in this case the steady state growth condition cannot be applied. Moreover, the initial phase of NW growth cannot be described with steady state growth conditions, either. In this work, we present a modeling approach for VLS NW growth based on numerical simulations, which is capable of describing the nucleation phase of the VLS growth process as well as a pulsed deposition process. PMID:23394587

Eisenhawer, Björn; Sivakov, Vladimir; Christiansen, Silke; Falk, Fritz

2013-02-18

404

Self-assembled vapor-liquid-solid growth of aligned Cu-SiO2 core-shell nanocable arrays on Cu substrates.  

PubMed

The Cu-SiO2 core-shell nanocable arrays on the Cu wafers have been synthesized via a simple thermal evaporation of the SiO powder. The morphology and structure of the as-synthesized Cu-SiO2 core-shell nanocables are characterized by using scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray energy dispersive spectrometer. The growth of amorphous SiO2 shell follows a vapor-liquid-solid mechanism, and then molten metal Cu will be diffused into the SiO2 nanotubes, forming the Cu-SiO2 core-shell nanocable arrays. It is found that the aligned Cu-SiO2 core-shell nanocables prefer to grow along the grooves of the Cu substrate, and the density of the Cu-SiO2 core-shell nanocable arrays can be controlled by adjusting the growth temperature. PMID:21121342

Chen, Yiqing; Zhou, Qingtao; Zhang, Xinhua; Su, Yong; Jia, Chong; Li, Qiang; Kong, Weihai; Wei, Meiqin

2010-12-01

405

Absence of vapor-liquid-solid growth during molecular beam epitaxy of self-induced InAs nanowires on Si  

NASA Astrophysics Data System (ADS)

The growth mechanism of self-induced InAs nanowires (NWs) grown on Si (111) by molecular beam epitaxy was investigated by in situ reflection high energy electron diffraction and ex situ scanning and transmission electron microscopy. Abrupt morphology transition and in-plane strain relaxation revealed that InAs NWs nucleate without any significant delay and under the absence of indium (In) droplets. These findings are independent of the As/In-flux ratio, revealing entirely linear vertical growth rate and nontapered NWs. No evidence of In droplets nor associated change in the NW apex morphology was observed for various growth termination procedures. These results highlight the absence of vapor-liquid-solid growth, providing substantial benefits for realization of atomically abrupt doping and composition profiles in future axial InAs-based NW heterostructures on Si.

Hertenberger, S.; Rudolph, D.; Bolte, S.; Döblinger, M.; Bichler, M.; Spirkoska, D.; Finley, J. J.; Abstreiter, G.; Koblmüller, G.

2011-03-01

406

On the calculation of momentum, heat, and mass transfer in laminar and turbulent boundary layer flows along a vaporizing liquid film  

NASA Astrophysics Data System (ADS)

A numerical method is presented for predicting the laminar and turbulent flow of a binary gas mixture along a plane vaporizing liquid film. The shear layer flow including the heat and mass transfer at the gas-liquid interface is described by a system of boundary-layer equations. Each of the parabolic equations is numerically solved using an implicit finite-difference method of Hermitian type. However, the overall solution procedure handles the coupled differential equations together with the boundary conditions in an explicit manner. Polynomials in terms of temperature are used to approximate the physical properties of the gas components at 1 atm pressure. Turbulence is accounted for by the algebraic eddy viscosity approach of Cebeci and Smith. The accuracy and efficiency of the numerical procedure developed is demonstrated for various temperatures of the external flow. A comparison of the numerical results with measurements in terms of flow profiles and Stanton numbers indicates good agreement.

Schroeppel, J.; Thiele, F.

1983-12-01

407

Absence of vapor-liquid-solid growth during molecular beam epitaxy of self-induced InAs nanowires on Si  

SciTech Connect

The growth mechanism of self-induced InAs nanowires (NWs) grown on Si (111) by molecular beam epitaxy was investigated by in situ reflection high energy electron diffraction and ex situ scanning and transmission electron microscopy. Abrupt morphology transition and in-plane strain relaxation revealed that InAs NWs nucleate without any significant delay and under the absence of indium (In) droplets. These findings are independent of the As/In-flux ratio, revealing entirely linear vertical growth rate and nontapered NWs. No evidence of In droplets nor associated change in the NW apex morphology was observed for various growth termination procedures. These results highlight the absence of vapor-liquid-solid growth, providing substantial benefits for realization of atomically abrupt doping and composition profiles in future axial InAs-based NW heterostructures on Si.

Hertenberger, S.; Rudolph, D.; Bichler, M.; Spirkoska, D.; Finley, J. J.; Koblmueller, G. [Walter Schottky Institut and Physik Department, Technische Universitaet Muenchen, Garching 85748 (Germany); Bolte, S. [Walter Schottky Institut and Physik Department, Technische Universitaet Muenchen, Garching 85748 (Germany); Department of Chemistry, Ludwig-Maximilians-Universitaet Muenchen, Munich 81377 (Germany); Doeblinger, M. [Department of Chemistry, Ludwig-Maximilians-Universitaet Muenchen, Munich 81377 (Germany); Abstreiter, G. [Walter Schottky Institut and Physik Department, Technische Universitaet Muenchen, Garching 85748 (Germany); Institute for Advanced Study, Technische Universitaet Muenchen, Garching 85748 (Germany)

2011-03-21

408

Composites “lithium halides in silica gel pores”: Methanol sorption equilibrium  

Microsoft Academic Search

This paper presents the methanol sorption equilibrium and phase composition of two composite sorbents “LiCl and LiBr confined to mesopores of silica gel”. Chemical phase analysis of the samples was performed by the differential dissolution method. Phase transformation of the composites during methanol sorption was characterized in situ by X-ray diffraction analysis. The isobars of methanol sorption on the composites

Larisa G. Gordeeva; Angelo Freni; Tamara A. Krieger; Giovanni Restuccia; Yuri I. Aristov

2008-01-01

409

Stars equilibrium  

NSDL National Science Digital Library

What causes the fusion reaction in a star's core? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to processes inside a star. Students read about the equilibrium process in a star, in which outward gas pressure equals inward gravitational pressure. Then, an interactive lab activity offers students the opportunity to predict temperature, pressure, and gravity changes that occur during equilibrium. The chemical reactions of the fusion process are presented, and more specific detailed reactions are available in a pop-up box. Student practice quizzes about the equilibrium process and pressure and gravity interactions inside the star are included, as are answers. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

410

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: I. vapor-liquid water equilibration of single salt solutions from 50 to 100[degrees]C  

SciTech Connect

The differences between oxygen and hydrogen isotope activity and composition ratios of water in single salt solutions (NaCl, KCl, MgCl[sub 2], CaCl[sub 2], Na[sub 2]SO[sub 4], and MgSO[sub 4]) were determined by means of a vapor-liquid water equilibration method over the temperature range of 50 to 100[degrees]C. A parallel equilibration technique of pure water and salt solutions with the same isotopic composition at the same experimental conditions enabled the precise determination of the isotope salt effects. Hydrogen isotope activity ratios of all of the salt solutions studied were appreciably higher than composition ratios. That is, D/H ratio of water vapor in isotope equilibrium with a solution increases as salt is added to the solution. Magnitudes of the hydrogen isotope effects are in the order CaCl[sub 2] [ge] MgCl[sub 2] > MgSO[sub 4] > KCl [approximately] NaCl > Na[sub 2]SO[sub 4] at the same molality. Except for KCl solutions at 50[degrees]C, oxygen isotope activity ratios in the solutions were lower than, or very close to, the composition ratios. The isotope effects observed are all linear with the molalities of the salt solutions, and either decrease with temperature or are almost constant over the temperature range. Salt solutions of divalent cations (Ca and Mg) exhibited oxygen isotope effects much larger than those of monovalent cations (Na and K). Magnitudes of the oxygen isotope effects in NaCl solutions, and of the hydrogen isotope effects in Na[sub 2]SO[sub 4] and MgSO[sub 4] solutions, may increase from 50 to 100[degrees]C. Our results agree with most of those from the literature near room temperature, but are at notable variance with those by Truesdell (1974) around 100[degrees]C. The results in this study and the literature data near room temperature were satisfactorily fitted to simple equations as a function of concentration of the salt solutions and temperature.

Horita, J.; Wesolowski, D.J.; Cole, D.R. (Oak Ridge National Laboratory, TN (United States))

1993-06-01

411

An extension of the Peng–Robinson equation of state for the correlation and prediction of high-pressure phase equilibrium in systems containing supercritical carbon dioxide and a salt  

Microsoft Academic Search

The development of an extended Peng–Robinson equation of state is described, which allows for the consideration of salts in calculations for the high-pressure vapor + liquid phase equilibrium. The extension employs two terms: a Debye–Hückel and a Margules term. The new equation is applied to systems with carbon dioxide, water, methanol, acetic acid, sodium chloride, and sodium acetate. For the

Georg Sieder; Gerd Maurer

2004-01-01

412

Volume crossover in deeply supercooled water adiabatically freezing under isobaric conditions  

NASA Astrophysics Data System (ADS)

The irreversible return of a supercooled liquid to stable thermodynamic equilibrium often begins as a fast process which adiabatically drives the system to solid-liquid coexistence. Only at a later stage will solidification proceed with the expected exchange of thermal energy with the external bath. In this paper we discuss some aspects of the adiabatic freezing of metastable water at constant pressure. In particular, we investigated the thermal behavior of the isobaric gap between the molar volume of supercooled water and that of the warmer ice-water mixture which eventually forms at equilibrium. The available experimental data at ambient pressure, extrapolated into the metastable region within the scheme provided by the reference IAPWS-95 formulation, show that water ordinarily expands upon (partially) freezing under isenthalpic conditions. However, the same scheme also suggests that, for increasing undercoolings, the volume gap is gradually reduced and eventually vanishes at a temperature close to the currently estimated homogeneous ice nucleation temperature. This behavior is contrasted with that of substances which do not display a volumetric anomaly. The effect of increasing pressures on the alleged volume crossover from an expanded to a contracted ice-water mixture is also discussed.

Aliotta, Francesco; Giaquinta, Paolo V.; Pochylski, Mikolaj; Ponterio, Rosina C.; Prestipino, Santi; Saija, Franz; Vasi, Cirino

2013-05-01

413

Isobaric Analogue States in Heavy Nuclei. I. Molybdenum Isotopes  

Microsoft Academic Search

Isobaric analogue states observed as compound-nucleus resonances in proton elastic scattering and (p, n) reactions have been studied using the target isotopes Mo92, Mo94, Mo95, Mo96, Mo97, Mo98, and Mo100. The observed resonances which occur at high excitations in the target-plus-proton system have been analyzed using a Coulomb-plus-single-level formula. The spectroscopic information for these resonances is compared with the analogue

C. F. Moore; P. Richard; C. E. Watson; D. Robson; J. D. Fox

1966-01-01

414

E1 radiation decay of isobaric analog resonances  

Microsoft Academic Search

Within the framework of the shell-optical model a quantitative interpretation for partial E1 radiation widths of isobaric analog resonances (IAR) has been proposed for near-magic nuclei over a wide atomic mass range. Spin-flip transitions as well as non-spin-flip ones are considered. A dependence of polarization effects on the spin-isospin part of the quasiparticle effective interaction is cleared up for transitions

V. G. Guba; O. A. Rumyantsev; M. G. Urin

1988-01-01

415

The Electroproduction of the Delta Isobar in Nuclei  

Microsoft Academic Search

We studied the effects of the nuclear environment on constituite nucleons by the electroproduction of the Delta isobar in H, C and Fe. Using incident electron beams with energies of 1.65, 1.50 and 0.65 GeV, we measured the inclusive cross sections for angles between 11 and 55 degrees. A longitudinal-transverse decomposition of the cross sections were made for q ^2

David Theodore Baran

1989-01-01

416

MEASUREMENTS OF ISOBARIC HEAT CAPACITY OF LIQUID PENTAFLUOROETHANE (R125)  

Microsoft Academic Search

The isobaric specific heat capacity, cp, of liquid pentafluoroethane (R125) was measured with flow calorimeter. Twenty-four cp values were obtained in the range of temperatures 285 - 325 K and pressures 1.5 - 3.0 MPa. The expanded uncertainties are estimated to be 8.4 mK in temperature, 10 kPa in pressure, and 1.3 × 10-2 kJ?kg-1?K-1 (about 0.6 %) in cp,

Xiang ZHAO; Shigehiro MATSUEDA; Haruki SATO

417

Measurement of isobaric heat capacity of R125  

Microsoft Academic Search

The specific isobaric heat capacity (cp) was measured for R125 (pentafluoroethane) in the gas phase by using a flow calorimeter. Twelve measurements for R125 were obtained at temperatures from 313 to 333K and at pressures from 0.8 to 2.4MPa. Some of them are close to the saturation curve. The expanded uncertainty (k=2) of the temperature measurements is estimated to be

Noboru Kagawa; Atsushi Matsuguchi; Koichi Watanabe

2011-01-01

418

All-atom force field for the prediction of vapor-liquid equilibria and interfacial properties of HFA134a.  

PubMed

A new all-atom force field capable of accurately predicting the bulk and interfacial properties of 1,1,1,2-tetrafluoroethane (HFA134a) is reported. Parameterization of several force fields with different initial charge configurations from ab initio calculations was performed using the histogram reweighting method and Monte Carlo simulations in the grand canonical ensemble. The 12-6 Lennard-Jones well depth and diameter for the different HFA134a models were determined by fitting the simulation results to pure-component vapor-equilibrium data. Initial screening of the force fields was achieved by comparing the calculated and experimental bulk properties. The surface tension of pure HFA134a served as an additional screening property to help discriminate an optimum model. The proposed model reproduces the experimental saturated liquid and vapor densities, and the vapor pressure for HFA134a within average errors of 0.7%, 4.4%, and 3.1%, respectively. Critical density, temperature, vapor pressure, normal boiling point, and heat of vaporization at 298 K are also in good agreement with experimental data with errors of 0.2%, 0.1%, 6.2%, 0%, 2.2%, respectively. The calculated surface tension is found to be within the experimental range of 7.7-8.1 mN.m(-1). The dipole moment of the different models was found to significantly affect the prediction of the vapor pressure and surface tension. The ability of the HFA134a models in predicting the interfacial tension against water is also discussed. The results presented here are relevant in the development of technologies where the more environmentally friendly HFA134a is utilized as a substitute to the ozone depleting chlorofluorocarbon propellants. PMID:19086791

Peguin, Robson P S; Kamath, Ganesh; Potoff, Jeffrey J; da Rocha, Sandro R P

2009-01-01

419

Preparation of carbon nano-microcoils by Ni3S2-catalyzed pyrolysis of acetylene and its vapor-liquid-solid-solid growth mechanism.  

PubMed

Carbon microcoils are generally prepared by catalytic chemical vapor deposition of acetylene, using Ni as the catalyst and thiophene as the promoter. In this work, Ni3S2 was chosen as the catalyst on purpose to avoid the introducing of noxious and unpleasant thiophene during the reaction process. The products obtained in the temperature range of 1013-1033 K were pure, regular and had perfect morphology. Using transmission electron microscope, Raman spectrometer and X-ray diffractometer, the microstructure of the as-prepared carbon microcoils were characterized, furthmore, energy dispersive spectrum and selected area electron diffraction analysis reveal that the growth of carbon microcoils is always accomplished with the transformation of the catalyst from Ni3S2 to Ni3C. We first observed that the fiber constructing the carbon microcoil is composed of three sub-fibers, which strongly supports the proposition of vapor-liquid-solid-solid growth mechanism. In this mechanism, every catalyst particle is in the state of the coexistence of solid and liquid. Carbon atoms firstly permeate into the liquid portion from gas, then disperse into the solid portion, and finally deposit from the catalyst grain to form the carbon microcoil. PMID:17256329

Li, Wenjun; Guo, Yanchuan; Chen, Lijuan

2006-12-01

420

Reports of investigations on: Derivation of an infinite-dilution activity coefficient model and application to two-component vapor/liquid equilibria data: Final report  

SciTech Connect

Infinite-dilution fugacity coefficients were obtained for the system fluorene/phenanthrene at thirteen temperatures by fitting total pressure across the entire mole fraction range by a computer routine. A thermodynamically consistent routine, that allowed for both positive and negative pressure deviations from the ideal values, was used to correlate data over the full mole fraction range from 0 to 1. The four-suffix Margules activity coefficient model without modification essentially served this purpose since total pressures and total pressure derivatives with respect to mole fraction were negligible compared to pressure measurement precision. The water/ethanol system and binary systems comprised of aniline, chlorobenzene, acetonitrile and other polar compounds were fit for total pressure across the entire mole fraction range for binary Vapor-Liquid-Equilbria (VLE) using the rigorous, thermodynamically consistent Gibbs-Duhem Relation derived by Ibl and Dodge. Data correlation was performed using a computer least squares procedure. Infinite-dilution fugacity coefficients were obtained using a modified Margules activity coefficient model.

Roper, V.P.; Kobayashi, R.

1988-02-01

421

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: II. Vapor-liquid water equilibration of mixed salt solutions from 50 to 100[degrees]C and geochemical implications  

Microsoft Academic Search

The difference between oxygen and hydrogen isotope activity and composition ratios of water in mixed salt solutions in the system Na-K-Mg-Ca-Cl-SO[sub 4]-H[sub 2]O was determined by means of a vapor-liquid water equilibration method over the temperature range of 50 to 100[degrees]C. The observed isotope salt effects in complex mixed salt solutions to very high ionic strengths agree quantitatively with calculations

J. Horita; D. R. Cole; D. J. Wesolowski

1993-01-01

422

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: I. Vapor-liquid water equilibration of single salt solutions from 50 to 100°C  

Microsoft Academic Search

The differences between oxygen and hydrogen isotope activity and composition ratios of water in single salt solutions (NaCl, KCl, MgCl 2 , CaCl 2 , Na 2 SO 4 , and MgSO 4 ) were determined by means of a vapor-liquid water equilibration method over the temperature range of 50 to 100°C. A parallel equilibration technique of pure water and

Juske Horita; David J. Wesolowski; David R. Cole

1993-01-01

423

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: I. vapor-liquid water equilibration of single salt solutions from 50 to 100[degrees]C  

Microsoft Academic Search

The differences between oxygen and hydrogen isotope activity and composition ratios of water in single salt solutions (NaCl, KCl, MgCl[sub 2], CaCl[sub 2], Na[sub 2]SO[sub 4], and MgSO[sub 4]) were determined by means of a vapor-liquid water equilibration method over the temperature range of 50 to 100[degrees]C. A parallel equilibration technique of pure water and salt solutions with the same

J. Horita; D. J. Wesolowski; D. R. Cole

1993-01-01

424

Vapor-liquid equilibria for 1,1-difluoroethane + acetylene and 1,1-difluoroethane + 1,1-dichloroethane at 303.2 K and 323.2 K  

SciTech Connect

Isothermal vapor-liquid equilibria for 1,1-difluoroethane (HFC-152a) + acetylene and 1,1-difluoroethane + 1,1-dichloroethane (HCC-150a) were measured in a circulation type apparatus at 303.2 K and 323.2 K. The experimental data were correlated with the Peng-Robinson equation of state using the Wong and Sandler mixing rule, and the relevant parameters are presented.

Lim, J.S.; Lee, Y.W.; Kim, J.D.; Lee, Y.Y. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Div. of Environmental and CFC Technology; Lee, J. [LG Chemical LTD/Research Park, Taejon (Korea, Republic of)

1996-09-01

425

Vapor-liquid equilibria for difluoromethane + dichloromethane at 303.2 and 313.2 K and 1,1-difluoroethane + vinyl chloride at 303.2 and 323.2 K  

SciTech Connect

Isothermal vapor-liquid equilibria for difluoromethane (HFC-32) + dichloromethane at 303.2 K and 313.2 K and 1,1-difluoroethane (HFC-152a) + vinyl chloride at 303.2 K and 323.2 K were measured in a circulation-type apparatus. The experimental data were correlated with the Peng-Robinson equation of state using the Wong and Sandler mixing rule, and the relevant parameters are presented.

Lim, J.S.; Lee, Y.W.; Lee, Y.Y. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Div. of Environmental and CFC Technology

1997-05-01

426

Vapor-liquid equilibria for hydrogen fluoride + difluoromethane, + 1,1,1,2-tetrafluoroethane, and + 1-chloro-1,2,2,2tetrafluoromethane at 283.3 and 298.2 K  

Microsoft Academic Search

The production of refrigerants involves the separation of multicomponent mixtures containing hydrogen fluoride, hydrogen chloride, and various chlorinated and fluorinated hydrocarbons. Therefore, it is essential to known the phase behavior of these mixtures. Isothermal vapor-liquid equilibria for hydrogen fluoride (HF) + difluoromethane (HFC-32), HF + 1,1,1,2-tetrafluoroethane (HFC-134a), and HF + 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) were measured by the P-T-x method at 283.3

J. Lee; H. Kim; J. S. Lim; J. D. Kim; Y. Y. Lee

1996-01-01

427

Metastable extensions of phase equilibrium lines and singular points of simple substance  

SciTech Connect

The thermodynamic properties of crystal, liquid, and gas in the stable and metastable states have been determined by molecular dynamics simulation of a system of 2048 Lennard-Jones particles. The spinodals of a superheated crystal, a superheated liquid, and a supersaturated vapor have been approximated; the spinodal for a supercooled liquid turns out to be nonexistent. The liquid-vapor, liquid-crystal, and crystal-vapor equilibrium curves and their extensions beyond the triple point have been calculated. It has been shown that, as distinct from the metastable extension of the saturation curve, which terminates at the zero isotherm, the metastable melting and sublimation curves terminate at, respectively, the stretched liquid and superheated crystal spinodals. The properties of the critical end points of metastable equilibrium of extended phases are considered.

Baidakov, V. G., E-mail: bai@itp.uran.ru; Protsenko, S. P. [Russian Academy of Sciences, Institute of Thermal Physics, Ural Division (Russian Federation)

2006-12-15

428

Models of p- T diagrams for a ternary system with invariant equilibrium of three solid phases, liquid, and vapor  

NASA Astrophysics Data System (ADS)

A version of a model of the p- T diagram for a ternary system in which three solid phases, liquid, and vapor are in invariant five-phase equilibrium is developed. The phase equilibria and phase transitions in the isobaric T- x- y diagram are analyzed, and isothermal and polythermal sections are presented.

Khaldoyanidi, K. A.

2013-03-01

429

Test of isospin purity in the A=42 isobaric analogs  

SciTech Connect

A careful measurement of the lifetime of the first 2{sub T=1}{sup +} state in {sup 42}Sc has allowed an accurate experimental test of isospin purity in the A=42 isobaric analogs by using the isospin formalism. A lifetime of 69 (18) fs has been determined, giving an isoscalar matrix element of 6.8 (8) W.u. Previous measurements of the lifetimes in the mirror nuclei {sup 42}Ca and {sup 42}Ti provided an isoscalar matrix element of 7.1 (5) W.u. which is very close to the presently measured value for {sup 42}Sc.

Orce, J.N.; McKay, C.J.; Choudry, S.N.; Lesher, S.R.; Bandyopadhyay, D.; McEllistrem, M.T. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States); Petkov, P. [Institute for Nuclear Research and Nuclear Energy, Sofia 1784 (Bulgaria); Institut fuer Kernphysik der Universitaet zu Koeln, 50937 Cologne (Germany); Mynk, M. [Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506 (United States); Yates, S.W. [Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506 (United States); Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506 (United States)

2004-07-01

430

Interfacial molecular structures of polyelectrolyte brush in contact with dry nitrogen, water vapor, liquid water, and aqueous electrolyte solution studied by sum frequency generation spectroscopy.  

PubMed

Interfacial structures of alkylated polyvinylpyridine (Cn-PVP) brushes with various side chain lengths (n = 2, 6, 12) in dry nitrogen, water vapor, liquid water, and aqueous electrolyte solution were investigated by sum frequency generation (SFG) spectroscopy. The SFG spectra of the polymer brushes in the CH stretching region in dry nitrogen revealed that the conformational order of the side chain depended on the chain length. The conformational order of the polymer brush with hexyl, C6, side chain, was very high, and the side chain was almost in all-trans conformation with the tilt angle of methyl group being ca. 34° with respect to the surface normal. Significant contribution from CH stretching of methylene group was observed in the SFG spectra of the polymer brush with the shorter, ethyl, C2, or longer, decyl, C12, side chains. Relative intensity of CH stretching of methylene group to that of methyl group, that is, degrees of gauche defects, increased significantly upon in contact with water vapor at all the brushes, and essentially no CH stretching peaks were observed when the brushes were in contact with liquid water, showing almost completely disordered conformational structure. These conformation changes were very fast, suggesting that the changes were related to the orientation change of the side chains. SFG spectra of the brush/water interface in the OH stretching region were dominated by OH stretching vibration of ice-like water. The higher was the electrolyte concentration, the lower was the OH intensity, reflecting the reduction of the double layer thickness in solution of higher electrolyte concentration. PMID:21077685

Uosaki, Kohei; Noguchi, Hidenori; Yamamoto, Rie; Nihonyanagi, Satoshi

2010-11-15

431

Isobaric analog states in odd-odd nuclei  

NASA Astrophysics Data System (ADS)

We calculate the excitation energies of Isobaric Analog states in selected odd-odd nuclei. We use the formula for e.g. ^96Ag E*(J=0^+T=2)= BE(^96Ag) - BE( ^96Pd) +VC where VC=E1 Z / A^(1/3) + E2 ; E1 =1.441 MeV ; E2 =-1.06 MeV. We list the following in MeV. ( ?(BE),VC,E*(calc), E*(single j),E* (multij shell model), Experiment) ^44Sc (4.435, 7.308, 2.873, 3.047, 3.418, 2.779) ^46Sc (2.160, 7.148, 5.024 , 4.949, 5.250, 5.022 ) ^52Mn (5..494, 8.399, 2.905, 2.774, 2.731, 2.926) ^60Cu ( 6.910, 9.430, 2.520, 2.235, 2.726 2.536 ) ^94Rh (10.386, 13.043, 2.657, 1.990 , 3.266,.........) ^96Ag (12.342, 13.574, 1.142, 0.900, 1.9172,........) The experimental energies of the isobaric analog states are known for the lighter nuclei but not for ^94Rh or ^96Ag. If we use the semi-empirical mass formula of Wapstra (2003) one gets the excitation energy in ^96Ag to be 0.367 MeV.

Zamick, Larry; Sharon, Yitzhak; Robinson, Shadow; Escuderos, Alberto

2013-04-01

432

Hard breakup of the deuteron into two ? isobars  

NASA Astrophysics Data System (ADS)

We study high-energy photodisintegration of the deuteron into two ? isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn??? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn??? scattering. We predict that the cross section of the deuteron breakup to ?++?- is 4-5 times larger than that of the breakup to the ?+?0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard ? isobars are the result of the disintegration of the preexisting ?? components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both ?++?- and ?+?0 channels to be similar.

Granados, Carlos G.; Sargsian, Misak M.

2011-05-01

433

Hard breakup of the deuteron into two ? -isobars  

NASA Astrophysics Data System (ADS)

Photodisintegration of the deuteron into two ?-isobars at large center of mass angles is studied within the QCD hard rescattering model (HRM). According to the HRM, the reaction proceeds in three main steps: the photon knocks the quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons emerging at large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn->?? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. We predict that the cross section of the deuteron breakup to &++circ;&-circ; is 4-5 times larger than that of the breakup to the &+circ;0? channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard ?-isobars are the result of the disintegration of initial ?? components of the deuteron wave function. In this case, the angular distributions and cross sections of the breakup in both &++circ;&-circ; and &+circ;0? channels are expected to be similar.

Granados, Carlos; Sargsian, Misak

2011-04-01

434

Thermodynamics of Si(OH) 4 in the vapor phase of water: Henry's and vapor-liquid distribution constants, fugacity and cross virial coefficients  

NASA Astrophysics Data System (ADS)

The fugacity coefficients of Si(OH) 4 are evaluated from solubilities of solid phases of SiO 2 in the vapor phase of water. The virial equation of state, truncated at the third virial coefficient, is employed to describe the fugacity coefficients of Si(OH) 4. The temperature dependencies of the second, B12, and the third, C112, cross virial coefficients for H 2O-Si(OH) 4 interactions are approximated by empirical relations. It is found that silica-water interactions in the vapor phase are significantly more non-ideal compared to water-water interactions. Knowledge of B12 and C112 allows calculation of solubilities of quartz (Q) and amorphous silica (AS) in steam up to the density of 200 kg m -3 in satisfactory agreement with available data, and should provide reasonable solubility values at temperatures where no experimental results exist. The calculated values of the solubility of Q and AS in saturated vapor up to the critical temperature of water, Tc, are tabulated. The partial molar properties of dilute solutes close to the critical point of water are governed by the Krichevskii parameter, the value of which for Si(OH) 4 is evaluated from available data (mainly vapor-liquid distribution constants for silica) to be equal to -187 ± 10 MPa. The knowledge of the thermodynamic properties of Si(OH) 4 in the ideal gas state and in the state of the standard solution in liquid water allows calculating Henry's constant, kH, for Si(OH) 4 up to 623.15 K at water saturation pressure P1?. The theoretically-based equation, containing the Krichevskii parameter, allows extrapolating kH values all the way toward the critical temperature of water. This, in turn, makes possible calculation of the solubility of quartz and amorphous silica in liquid water at P1? at all temperatures up to Tc. The presented results should be useful for modeling solid-liquid-vapor, solid-vapor and liquid-vapor equilibria in the H 2O-SiO 2 system at steam densities up to 200 kg m -3.

Plyasunov, Andrey V.

2012-01-01

435

Phase equilibrium data for development of correlations for coal fluids: Report for the period August 15, 1987 to December 31, 1987  

SciTech Connect

During the present report period, data have been obtained on the solubilities of carbon dioxide in benzene at 310.2 K, and of ethane in n-hexatriacontane at 373.2 K and in n-tetratetracontane at 373.2 K and 423.2 K. These data are well described by the Soave and Peng-Robinson equations of state. Also, during this report period a low pressure recirculating vapor-liquid equilibrium still has been designed and constructed. Preliminary tests on selected systems confirm excellent operation of the new apparatus. 17 refs., 7 figs., 10 tabs.

Robinson, R.L. Jr.; Gasem, K.A.M.; Raff, A.M.; Qin, Yanlong

1988-01-19

436

Dynamical isobar models and {pi}-N scattering data  

SciTech Connect

Isobar amplitudes for pion-nucleon elastic and production reactions are constructed from a dynamical theory. The framework of point form relativistic quantum mechanics is used to derive a relativistic Lippmann-Schwinger equation linking elastic and production channels. The dynamics is contained in a mass operator which is the sum of a free and interacting mass operator. For a separable interacting mass operator, the Lippmann-Schwinger equations can be solved analytically; the resulting matrix equations have determinants whose zeros give the positions of multiple resonances in the same angular momentum channels. Though varying parameters to fit data is highly nonlinear, procedures are developed for fitting elastic and inelastic data. Fits to data are presented for the P{sub 33} partial wave channel in pion-nucleon scattering. {copyright} {ital 1998} {ital The American Physical Society}

Klink, W.H.; Rogers, M. [Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242 (United States)

1998-12-01

437

The isobaric multiplet mass equation for A?71 revisited  

NASA Astrophysics Data System (ADS)

Accurate mass determination of short-lived nuclides by Penning-trap spectrometers and progress in the spectroscopy of proton-rich nuclei have triggered renewed interest in the isobaric multiplet mass equation (IMME). The energy levels of the members of T=1/2,1,3/2, and 2 multiplets and the coefficients of the IMME are tabulated for A?71. The new compilation is based on the most recent mass evaluation (AME2011) and it includes the experimental results on energies of the states evaluated up to end of 2011. Taking into account the error bars, a significant deviation from the quadratic form of the IMME for the A=9,35 quartets and the A=32 quintet is observed.

Lam, Yi Hua; Blank, Bertram; Smirnova, Nadezda A.; Bueb, Jean Bernard; Antony, Maria Susai

2013-11-01

438

Vapor-liquid equilibria for hydrogen fluoride + difluoromethane, + 1,1,1,2-tetrafluoroethane, and + 1-chloro-1,2,2,2-tetrafluoromethane at 283.3 and 298.2 K  

SciTech Connect

The production of refrigerants involves the separation of multicomponent mixtures containing hydrogen fluoride, hydrogen chloride, and various chlorinated and fluorinated hydrocarbons. Therefore, it is essential to known the phase behavior of these mixtures. Isothermal vapor-liquid equilibria for hydrogen fluoride (HF) + difluoromethane (HFC-32), HF + 1,1,1,2-tetrafluoroethane (HFC-134a), and HF + 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) were measured by the P-T-x method at 283.3 and 298.2 K. Vapor compositions were calculated from these results. Among these systems, the HF + HFC-134a and HF + HCFC-124 systems exhibit minimum boiling azeotropes at both temperatures.

Lee, J.; Kim, H. [Seoul National Univ. (Korea, Republic of). Dept. of Chemical Engineering; Lim, J.S.; Kim, J.D.; Lee, Y.Y. [KIST, Seoul (Korea, Republic of). CFC Alternatives Technology Center

1996-01-01

439

Vapor-liquid equilibria for 1,1,1,2-tetrafluoroethane + 1-chloro-1,2,2,2-tetrafluoroethane and 1-chloro-1,2,2,2-tetrafluoroethane + 1-chloro-1,1-difluoroethane systems  

SciTech Connect

Isothermal vapor-liquid equilibria were determined for two binary mixtures of refrigerants with a circulation type apparatus. The 1,1,1,2-tetrafluoroethane (HFC-134a) + 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) system was studied at 296.45, 302.25, and 307.25 K. The 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124) + 1-chloro-1,1-difluoroethane (HCFC-142b) system was studied at 298.15 and 312.15 K. At each temperature, the pressure and vapor and liquid compositions were measured. Results were correlated with the Peng-Robinson equation of state.

Lee, J.; Lee, J.; Kim, H. [Seoul National Univ. (Korea, Republic of). Dept. of Chemical Engineering

1996-07-01

440

Hard breakup of the deuteron into two {Delta} isobars  

SciTech Connect

We study high-energy photodisintegration of the deuteron into two {Delta} isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn{yields}{Delta}{Delta} scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn{yields}{Delta}{Delta} scattering. We predict that the cross section of the deuteron breakup to {Delta}{sup ++}{Delta}{sup -} is 4-5 times larger than that of the breakup to the {Delta}{sup +}{Delta}{sup 0} channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard {Delta} isobars are the result of the disintegration of the preexisting {Delta}{Delta} components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both {Delta}{sup ++}{Delta}{sup -} and {Delta}{sup +}{Delta}{sup 0} channels to be similar.

Granados, Carlos G.; Sargsian, Misak M. [Florida International University, Miami, Florida 33199 (United States)

2011-05-15

441

Analysis of Isobaric Expansion Data Based on Soft-Sphere Equation of State for Liquid Metals  

NASA Astrophysics Data System (ADS)

An analysis of isobaric expansion data for the liquid phase of refractory metals is presented. Simple equations of state based on soft-sphere model are used to generalize available experimental data on vapor pressure as well as isobaric and adiabatic expansion of liquid metals. In the cases of discrepancy of isobaric expansion data obtained by different experimental teams several equation-of-state variants are developed. It is shown for tungsten, tantalum, and vanadium that higher value of ([partial differential]V/[partial differential]T)P leads to lower values of critical density and pressure.

Levashov, Pavel R.; Fortov, Vladimir E.; Khishchenko, Konstantin V.; Lomonosov, Igor' V.

2002-07-01

442

Stable carbon and hydrogen isotope fractionation of dissolved organic groundwater pollutants by equilibrium sorption  

NASA Astrophysics Data System (ADS)

Linear free energy relationships (LFERs) were established which relate equilibrium vapor-liquid isotope effects to stable carbon and hydrogen isotope enrichment factors for equilibrium sorption to geosorbents. The LFERs were established for normal, cyclic or branched alkanes, monoaromatic hydrocarbons, and chloroethenes. These LFERs predict that isotopic light compounds sorb more strongly than their heavy counterparts. Defining fractionation as in classical literature by "heavy divided by light", carbon enrichment factors for equilibrium sorption were derived which ranged from - 0.13 ± 0.04‰ (benzene) to - 0.52 ± 0.19‰ (trichloroethene at 5-15 °C). Hydrogen enrichment factors for sorption of 14 different compounds were between - 2.4 and - 9.2‰. For perdeuterated hydrocarbons the predicted enrichment factors ranged from - 19 ± 5.4‰ (benzene) to - 64 ± 30‰ (cyclohexane). Equilibrium sorption experiments with a soil and activated carbon as sorbents were performed in the laboratory for perdeuterocyclohexane and perdeuterotoluene. The measured D/H enrichments agreed with the LFER prediction for both compounds and both sorbents within the uncertainty estimate of the prediction. The results of this work suggest that equilibrium sorption does create only very small isotope shifts for 13C in groundwater pollutants in aquifers. It is also suggested that deuterium shifts are expected to be higher, especially for strongly sorbing pollutants.

Höhener, Patrick; Yu, Xianjing

2012-03-01

443

Stable carbon and hydrogen isotope fractionation of dissolved organic groundwater pollutants by equilibrium sorption.  

PubMed

Linear free energy relationships (LFERs) were established which relate equilibrium vapor-liquid isotope effects to stable carbon and hydrogen isotope enrichment factors for equilibrium sorption to geosorbents. The LFERs were established for normal, cyclic or branched alkanes, monoaromatic hydrocarbons, and chloroethenes. These LFERs predict that isotopic light compounds sorb more strongly than their heavy counterparts. Defining fractionation as in classical literature by "heavy divided by light", carbon enrichment factors for equilibrium sorption were derived which ranged from -0.13±0.04‰ (benzene) to -0.52±0.19‰ (trichloroethene at 5-15 °C). Hydrogen enrichment factors for sorption of 14 different compounds were between -2.4 and -9.2‰. For perdeuterated hydrocarbons the predicted enrichment factors ranged from -19±5.4‰ (benzene) to -64±30‰ (cyclohexane). Equilibrium sorption experiments with a soil and activated carbon as sorbents were performed in the laboratory for perdeuterocyclohexane and perdeuterotoluene. The measured D/H enrichments agreed with the LFER prediction for both compounds and both sorbents within the uncertainty estimate of the prediction. The results of this work suggest that equilibrium sorption does create only very small isotope shifts for (13)C in groundwater pollutants in aquifers. It is also suggested that deuterium shifts are expected to be higher, especially for strongly sorbing pollutants. PMID:22055158

Höhener, Patrick; Yu, Xianjing

2011-09-29

444

Vapor-liquid-solid (VLS) synthesis of alpha-monoclinic selenium and antimony selenide nanowires and sonication synthesis of blue photoluminescent zero-dimensional nanoparticles  

NASA Astrophysics Data System (ADS)

Semiconducting nanostructures such as nanowires and 0-D nanoparticles have received great interest due to their improved properties in comparison with macroscopic materials. Therefore, these nanostructures have attracted considerable attention for optoelectronics and biological applications, among others. In this way, this thesis reports the synthesis of alpha-monoclinic selenium and antimony selenide (Sb2Se3) semiconducting nanowires using a physical vapor-liquid-solid (VLS) process for the first time. In addition, synthesis of naturally dispersed Sb2Se 3 0-D nanoparticles using a sonication process is also reported here for the first time. Crystalline alpha-monoclinic selenium nanowires with diameters in the range between 20 nm and 1im and lengths up to 30 mum were synthesized. The majority of these VLS synthesized nanowires have a diameter of ~50 nm. As-obtained nanowires grew perpendicular to the (053) plane and exhibit an energy band-gap of 2.20 +/- 0.05 eV, showing a blue shift of 0.18 eV relative to the bulk than is attributed to quantum confinement from the most abundant produced nanowires (~50 nm). Crystalline Sb2Se3 nanowires with diameters in the range between 20 nm and 2mum and lengths up to 30 mum were synthesized. The diameter of the most abundant produced nanowires is ~800 nm. Our nanowires are oriented along the [010] crystallographic direction. Growth along this orientation is being reported for the first time. Due to the anisotropy of the lattice, [010] oriented nanowires have properties different to the ones produced by the other methods that are [001] oriented. This thesis also analyses the controversial band gap energy results reported in the literature and conclude that is due to incorrect interpretation of experimental measurements. Photoluminescence (PL) measurements of powdered crystalline bulk Sb2Se3 at room temperature and under UV excitation are reported here for the first time. The PL spectra show that Sb2Se3 crystalline exhibits high photoluminescence in the range between 1.79 and 4.35 eV. This photoluminescence seems to be the source of some erroneous energy band gaps that have been reported. Synthesized Sb2Se3 0-D crystalline nanoparticles have diameters in the range between 2.0 +/- 0.1 nm and 6.0 +/- 0.1 nm, being ~ 3.8 +/- 0.1 nm the most produced size. Sb2Se 3 0-D nanoparticles in suspension exhibited blue luminescence detectable by the eye under UV excitation at room temperature, with a wide PL emission peak at 422 nm (2.94 eV). These Sb2Se3 nanoparticles have on the order of hundred times larger emission than the bulk material with the same molar concentration. Therefore, this effect is the result of the increase in the emission surface due to higher surface to volume ratio.

Farfan Mendoza, Willinton

445

Gas-phase purification enables accurate, large-scale, multiplexed proteome quantification with isobaric tagging  

PubMed Central

We describe a mass spectrometry method, QuantMode, which improves the accuracy of isobaric tag–based quantification by alleviating the pervasive problem of precursor interference—co-isolation of impurities—through gas-phase purification. QuantMode analysis of a yeast sample ‘contaminated’ with interfering human peptides showed substantially improved quantitative accuracy compared to a standard scan, with a small loss of spectral identifications. This technique will allow large-scale, multiplexed quantitative proteomics analyses using isobaric tagging.

Wenger, Craig D; Lee, M Violet; Hebert, Alexander S; McAlister, Graeme C; Phanstiel, Douglas H; Westphall, Michael S; Coon, Joshua J

2011-01-01

446

Coal gasification pilot plant support studies. Subtask 3-2. Phase equilibrium studies as applied to treatment of raw bases from coal gasification. [122 to 403/sup 0/F and 590 to 2800 psia  

SciTech Connect

Several methods to predict the phase equilibrium behavior of gas mixtures at different temperatures and pressures appear in the literature. In this study, four of these correlations have been evaluated using experimentally derived vapor-liquid equilibrium compositions and phase densities. The experiments were conducted with simulated coal gasification product gas-benzene mixtures over a temperature range of 122/sup 0/ to 403/sup 0/F and pressure range of 590 to 2800 psia. The four correlations evaluated were the Peng-Robinson, the Soave Redlich-Kwong, the Redlich-Kwong Chao-Seader, and the Redlich-Kwong Grayson-Streed. Interaction coefficients for several of the components of interest for use in the Peng-Robinson equation of state were also determined from available binary vapor-liquid equilibrium data. Of the four available vapor-equilibrium correlations evaluated, the Peng-Robinson correlation provided the closest approximation to the experimental results. The next closest correlations were the Soave Redlich-Kwong, the Redlich-Kwong Chao-Seader, and the Redlich-Kwong Grayson-Streed.

Not Available

1980-10-01

447

Di-trinucleon cluster resonances in A=6 isobar nuclei  

SciTech Connect

The di-trinucleon clustering resonances of {sup 3}He+{sup 3}He in {sup 6}Be and t+t in {sup 6}He were studied via the {sup 6}Li({sup 3}He,t {sup 3}He) and {sup 6}Li({sup 7}Li,{sup 7}Be t) reactions at incident energies of 450 and 455 MeV, respectively. A new resonance in {sup 6}Be was found at E{sub x}=18.0{+-}1.2 MeV with a width of 9.2{+-}1.0 MeV in the binary decay channel of {sup 6}Be{yields}{sup 3}He+{sup 3}He. The resonance in {sup 6}He previously reported was also observed at E{sub x}=18.0{+-}1.0 MeV with a width of 9.5{+-}1.0 MeV in the binary decay channel of {sup 6}He {yields}t+t. The branching ratios of the resonances for each binary decay were both 0.7{+-}1.0, which was larger than the branching ratio calculated in a statistical model by two orders of magnitude. The angular correlations measured for t and {sup 3}He particles in the binary decay show a contribution dominantly from the multipolarity of L=1. We suggest that the resonances are the members of the isobaric triplet of the {sup 3}P resonances in A=6 nuclei.

Yamagata, T.; Akimune, H.; Hara, K.Y.; Kinoshita, M.; Ohta, M.; Shiokawa, A.; Utsunomiya, H. [Department of Physics, Konan University, Kobe 658-8501 (Japan); Nakayama, S.; Fushimi, K.; Ichihara, K.; Matsui, Y. [Department of Physics, University of Tokushima, Tokushima 770-8502 (Japan); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Advance Photon Research Center, JAERI, Kizu 619-0215 (Japan); Greenfield, M.B. [Department of Physics, International Christian University, Tokyo 113-0033 (Japan); Hara, K.; Hashimoto, H.; Kawase, K.; Nakanishi, K. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Tanaka, M. [Kobe Tokiwa College, Kobe 654-0838 (Japan); Yosoi, M. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2005-06-01

448

Glycan Analysis by Isobaric Aldehyde Reactive Tags and Mass Spectrometry  

PubMed Central

Glycans play significant roles in physiological and pathological processes. Therefore, quantitative analysis of glycans from normal and disease specimens can provide insight into disease onset and progression. Relative glycan quantification usually requires modification of the glycans with either chromogenic or fluorogenic tags for optical measurement or isotopic tags for mass spectrometric analysis. Due to rapid advances in mass spectrometry (MS) instruments in resolution, sensitivity and speed, MS-based methods have become increasingly popular for glycan analysis in the past decade. However, current isotopic tags for glycan labeling are mostly mass-shift tags generating mass differences in precursor ions for quantification, which can complicate mass spectra. In this study, we report the synthesis and characterization of isobaric aldehyde reactive tags (iARTs) for glycan quantification using tandem MS. We applied iARTs to the relative identification and quantification of glycans of gp120, a glycoprotein from human immunodeficiency virus. The results show that iARTs provide strong signals for glycan identification. Although we only show the synthesis and characterization of two iARTs reagents, iARTs can be readily expanded to six-plex tags for quantitative analysis of six samples concurrently.

Yang, Shuang; Yuan, Wei; Yang, Weiming; Zhou, Jianying; Harlan, Robert; Edwards, James; Li, Shuwei; Zhang, Hui

2013-01-01

449

Glycan analysis by isobaric aldehyde reactive tags and mass spectrometry.  

PubMed

Glycans play significant roles in physiological and pathological processes. Therefore, quantitative analysis of glycans from normal and disease specimens can provide insight into disease onset and progression. Relative glycan quantification usually requires modification of the glycans with either chromogenic or fluorogenic tags for optical measurement or isotopic tags for mass spectrometric analysis. Because of rapid advances in mass spectrometry (MS) instruments in resolution, sensitivity, and speed, MS-based methods have become increasingly popular for glycan analysis in the past decade. However, current isotopic tags for glycan labeling are mostly mass-shift tags generating mass differences in precursor ions for quantification, which can complicate mass spectra. In this study, we report the synthesis and characterization of isobaric aldehyde reactive tags (iARTs) for glycan quantification using tandem MS. We applied iARTs to the relative identification and quantification of glycans of gp120, a glycoprotein from human immunodeficiency virus. The results show that iARTs provide strong signals for glycan identification. Although we only show the synthesis and characterization of two iARTs reagents, iARTs can be readily expanded to six-plex tags for quantitative analysis of six samples concurrently. PMID:23895018

Yang, Shuang; Yuan, Wei; Yang, Weiming; Zhou, Jianying; Harlan, Robert; Edwards, James; Li, Shuwei; Zhang, Hui

2013-08-12

450

Performance of isobaric and isotopic labeling in quantitative plant proteomics.  

PubMed

Mass spectrometry has become indispensable for peptide and protein quantification in proteomics studies. When proteomics technologies are applied to understand the biology of plants, two-dimensional gel electrophoresis is still the prevalent method for protein fractionation, identification, and quantitation. In the present work, we have used LC-MS to compare an isotopic (ICPL) and isobaric (iTRAQ) chemical labeling technique to quantify proteins in the endosperm of Ricinus communis seeds at three developmental stages (IV, VI, and X). Endosperm proteins of each stage were trypsin-digested in-solution, and the same amount of peptides was labeled with ICPL and iTRAQ tags in two orders (forward and reverse). Each sample was submitted to nanoLC coupled to an LTQ-Orbitrap high-resolution mass spectrometer. Comparing labeling performance, iTRAQ was able to label 99.8% of all identified unique peptides, while 94.1% were labeled by ICPL. After statistical analysis, it was possible to quantify 309 (ICPL) and 321 (iTRAQ) proteins, from which 95 are specific to ICPL, 107 to iTRAQ, and 214 common to both labeling strategies. We noted that the iTRAQ quantification could be influenced by the tag. Even though the efficiency of the iTRAQ and ICPL in protein quantification depends on several parameters, both labeling methods were able to successfully quantify proteins present in the endosperm of castor bean during seed development and, when combined, increase the number of quantified proteins. PMID:22452248

Nogueira, Fábio C S; Palmisano, Giuseppe; Schwämmle, Veit; Campos, Francisco A P; Larsen, Martin R; Domont, Gilberto B; Roepstorff, Peter

2012-04-09

451

Prediction of vapor–liquid equilibrium in polymer solutions using a Peng–Robinson group contribution model 1 Paper presented at the International Conference on Applied Physical Chemistry, Warsaw, 13–15 November 1996. 1  

Microsoft Academic Search

The objective of this study is to extend the applicability of a Peng–Robinson group contribution method (PRASOG), which combines a zero pressure gE mixing rule for Peng–Robinson EOS with ASOG group contribution model, to polymer solutions. The solvent activities in polymer solutions have been predicted by PRASOG-FV which evaluates the gE from ASOG-FV proposed previously in order to predict the

K Tochigi; H Futakuchi; K Kojima

1998-01-01

452

The Chemical Equilibrium Problem.  

National Technical Information Service (NTIS)

It has long been known that the problem of determining the equilibrium composition of a solution of chemically reacting species could be formulated as a constrained minimum problem. Previous methods for solving the chemical equilibrium problem in this for...

J. H. Bigelow

1968-01-01

453

Chapman Cycle Equilibrium Calculator  

NSDL National Science Digital Library

The Chapman Cycle Equilibrium Calculator solves for the equilibrium solution of the chemical reactions in the Chapman Cycle, assuming a solar flux equivalent to that at the top of the Earth's atmosphere. A Newton-Rhapson method is used to find the solution, which requires an initial guess as to the equilibrium solution.

The Shodor Education Foundation, Inc.

454

Liquid-vapor equilibrium for ternary natural gas system  

SciTech Connect

Vapor liquid equilibrium (VLE) data were measured for the nitrogen + carbon dioxide binary system at 220 and 240 K and for the methane + carbon dioxide system at 219.26, 240 and 270 K. Ternary VLE measurements were made for the system N + CH/sub 4/ + CO/sub 2/ at 220 K and 6.080, 9.119 and 12.159 MPa, 233.15 K at 8.106 MPa, and 240 K at 7.093, 9.119 and 12.159 MPa. The multifluid reference corresponding states method proposed by Teja and Rice was applied to VLE calculations and the results of this method for the binary and ternary systems were compared with the results of the Lee-Kesler corresponding states correlation and the Peng-Robinson equation of state. The multifluid and Lee-Kesler methods give comparable results for the constituent binaries of the N/sub 2/ + CH/sub 4/ + CO/sub 2/ system. However, the multifluid model predictions for the ternary system were superior to the predictions of the Lee-Kesler method. The Peng-Robinson equation of state was found to be better than both corresponding states methods for both binary and ternary system VLE predictions. None of the methods produced good representation near the critical points of the binary and ternary systems.

Kidnay, A.J.; Sloan, E.D.

1981-09-01

455

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: III. Vapor-liquid water equilibration of NaCl solutions to 350°C  

Microsoft Academic Search

The effect of dissolved NaCl on equilibrium oxygen and hydrogen isotope fractionation factors between liquid water and water vapor was precisely determined in the temperature range from 130–350°C, using two different types of apparatus with static or dynamic sampling techniques of the vapor phase. The magnitude of the oxygen and hydrogen isotope effects of NaCl is proportional to the molality

Juske Horita; David R. Cole; David J. Wesolowski

1995-01-01

456

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: III. Vapor-liquid water equilibration of NaCl solutions to 350°C  

Microsoft Academic Search

The effect of dissolved NaCl on equilibrium oxygen and hydrogen isotope fractionation factors between liquid water and water vapor was precisely determined in the temperature range from 130-350°C, using two different types of apparatus with static or dynamic sampling techniques of the vapor phase. The magnitude of the oxygen and hydrogen isotope effects of NaCl is proportional to the molality

Juske Horita; David R. Cole; David J. Wesolowski

1995-01-01

457

Vapor-liquid equilibria for the systems composed of 1-chloro-1,1-difluoroethane, 1,1-dichloro-1-fluoroethane, and 1,1,1-trichloroethane at 50.1 C  

SciTech Connect

Isothermal vapor-liquid equilibria for the three binary systems 1-chloro-1,1-difluoroethane + 1,1-dichloro-1-fluoroethane, 1-chloro-1,1-difluoroethane + 1,1,1-trichloroethane, and 1,1-dichloro-1-fluoroethane + 1,1,1-trichloroethane and the ternary system 1-chloro-1,1-difluoromethane + 1,1-dichloro-1-fluoroethane + 1,1,1-trichloroethane have been measured at 50.1 C. The experimental data for the binary systems are correlated with the Peng-Robinson equation of state, and the relevant parameters are presented. The predicted results for the ternary system were found to be in good agreement with the experimental data.

Kang, Y.W.; Lee, Y.Y. [KIST, Seoul (Korea, Republic of). CFC Alternatives Technology Center

1996-03-01

458

Cost-effective isobaric tagging for quantitative phosphoproteomics using DiART reagents.  

PubMed

We describe the use of an isobaric tagging reagent, Deuterium isobaric Amine Reactive Tag (DiART), for quantitative phosphoproteomic experiments. Using DiART tagged custom mixtures of two phosphorylated peptides from alpha casein and their non-phosphorylated counterparts, we demonstrate the compatibility of DiART with TiO2 affinity purification of phosphorylated peptides. Comparison of theoretical vs. experimental reporter ion ratios reveals accurate quantification of phosphorylated peptides over a dynamic range of more than 15-fold. Using DiART labelling and TiO2 enrichment (DiART-TiO2) with large quantities of proteins (8 mg) from the cell lysate of model fungus Aspergillus nidulans, we quantified 744 unique phosphopeptides. Overlap of median values of TiO2 enriched phosphopeptides with theoretical values indicates accurate trends. Altogether these findings confirm the feasibility of performing quantitative phosphoproteomic experiments in a cost-effective manner using isobaric tagging reagents, DiART. PMID:24129742

Ramsubramaniam, Nikhil; Tao, Feng; Li, Shuwei; Marten, Mark R

2013-10-16

459

Analysis of Isobaric Expansion Data Based on Soft-Sphere Equation of State for Liquid Metals  

NASA Astrophysics Data System (ADS)

The knowledge of thermodynamic properties of liquid metals is interesting for investigation of different processes at high energy densities. Fast isobaric expansion experiments allow for a measurements of thermodynamic parameters of metals in liquid phase near evaporation curve but there are contradictions in such experimental information between different authors. In this work we present equation of state (EOS) calculation results for 15 metals on the basis of soft-sphere model(D.A. Young, report UCRL-52352 (1977)). Comparison with available experimental data on isobaric expansion, adiabatic release, vapour pressure and liquid metals density measurements near evaporation curve is carried out. In the case of vanadium, tantalum and tungsten several variants of EOS for each metal are constructed with the help of different sets of isobaric expansion data and more reliable variants of EOS are chosen. The analysis of calculated critical parameters is made.

Levashov, P. R.; Fortov, V. E.; Khishchenko, K. V.; Lomonosov, I. V.

2001-06-01

460

An experimental apparatus proposed for efficient removal of isobaric contaminants in negative ion beams  

NASA Astrophysics Data System (ADS)

Isobaric contaminants are often problematical in accelerated negative ion beams for research at certain radioactive ion beam (RIB) and accelerator mass spectrometry (AMS) facilities since their presence in low-intensity rare isotopic beams seriously compromise experimental results. This article describes a non-resonant, laser-based photo-detachment apparatus for use at these facilities, which, according to calculations efficiently removes isobaric contaminants from these beams. The advantage of the system for isobaric contaminant removal over other systems proposed to date lies in its ability to efficiently capture easily transportable energetic negative ion beams with low, intermediate or high energy spreads by a superconducting solenoid magnetic field. The ability to change the diameter of captured beams by adjusting the magnetic field strength permits optimum control of the radial overlap of the laser/negative ion beam profiles over an extended interaction region under high vacuum conditions without retarding optical affect, collision-cooling or capture losses.

Alton, G. D.; Zhang, Y.

2008-09-01

461

Photoproduction of ?+ p-pairs on the 16O nucleus and isobar configurations  

NASA Astrophysics Data System (ADS)

The yield of the 16O(?, ?+ p) reaction has been measured in the region of the excitation of the ?(1232) isobar at high momentum transfers to the residual nuclear system. The experimental data are interpreted within the model taking into account manifestations of isobar configurations in the ground state of the 16O nucleus. Direct and exchange mechanisms of the production of pions with emission of one and two nucleons, which follow from the structures of the density matrices for these reactions, have been considered. The probability of the production of the ?-isobar in the ground state of the 16O nucleus has been empirically estimated as P ? = 0.019 ± 0.003 ± 0.003.

Glavanakov, I. V.; Grabmayer, P.; Krechetov, Yu. F.; Tabachenko, A. N.

2013-04-01

462

Covariant and self-consistent vertex corrections for pions and isobars in nuclear matter  

SciTech Connect

We evaluate the pion and isobar propagators in cold nuclear matter self-consistently applying a covariant form of the isobar-hole model. Migdal's vertex correction effects are considered systematically in the absence of phenomenological soft form factors. Saturated nuclear matter is modeled by scalar and vector mean fields for the nucleon. It is shown that the short-range dressing of the {pi}N{delta} vertex has a significant effect on the pion and isobar properties. Using realistic parameters sets we predict a downward shift of about 50 MeV for the {delta} resonance at nuclear saturation density. The pionic soft modes are much less pronounced than in previous studies.

Korpa, C. L.; Lutz, M. F. M.; Riek, F. [Department of Theoretical Physics, University of Pecs, Ifjusag u. 6, H-7624 Pecs (Hungary); Gesellschaft fuer Schwerionenforschung (GSI), Planck Str. 1, D-64291 Darmstadt (Germany)

2009-08-15

463

Effects of consistent and inconsistent isobar coupling in the nuclear medium  

NASA Astrophysics Data System (ADS)

We investigate effects of consistent (conserving the number of degrees of freedom) and inconsistent pion-nucleon-isobar couplings on the isobar propagator in vacuum and in nuclear medium. Using the consistent coupling in conjunction with a convenient basis leads to significant simplification of the isobar vacuum and in-medium self-energy and dressed propagator compared to the case of inconsistent interaction. The higher-derivative nature of the consistent interaction requires a suitable compensation by an additional form-factor term or adjustment in the used cut-off values. This modification is straightforward to perform and assures that the physical observables connected to the spin-3/2 sector in vacuum and nuclear medium acquire values indistinguishable from the ones obtained by using an inconsistent coupling.

Korpa, C. L.

2012-01-01

464

Separation by extractive distillation of mixtures of alcohols and the esters of acetic acid. 1: Solvent selection  

Microsoft Academic Search

Isobaric 760-mm-Hg vapor-liquid equilibrium data were measured for the binary systems methyl acetate-methanol (1), ethyl acetate-ethanol (2), n-propanol-n-propyl acetate (3), and isopropanol-isopropyl acetate (4) by using a recirculation still designed in the present authors laboratory. The data were tested for experimental thermodynamic consistency, and were correlated by applying the van Laar and Wilson equations. The following minimum azeotropes were found:

E. Cepeda; J. M. Resa

1994-01-01

465

Density, refractive index and speed of sound for mixtures of ethyl acetate with 2-butanol and 3-methyl-1-butanol  

Microsoft Academic Search

Densities, refractive indices and speeds of sound at 298.15, 303.15, and 308.15K are reported for the binary mixtures ethyl acetate + 2-butanol and ethyl acetate + 3-methyl-1-butanol. Isobaric vapor–liquid equilibrium data at 101.3kPa were determined for the ethyl acetate + 3-methyl-1-butanol system. Excess molar volumes, refractive index deviations and changes of speed of sound on mixing were calculated from experimental

José M Resa; Cristina González; Marina Juez; Salomé Ortiz de Landaluce

2004-01-01

466

VLE measurements of binary mixtures of methanol, ethanol, 2-methoxy-2-methylpropane, and 2-methoxy-2-methylbutane at 101.32 kPa  

Microsoft Academic Search

Isobaric vapor-liquid equilibrium data for 2-methoxy-2-methylpropane + methanol, 2-methoxy-2-methylpropane + ethanol, methanol + 2-methoxy-2-methylbutane, ethanol + 2-methoxy-2-methylbutane, and 2-methoxy-2-methylpropane + 2-methoxy-2-methylbutane were determined at 101.32 kPa. Fredenslund et al.`s test confirmed the results to be thermodynamically consistent. The VLE data were satisfactorily correlated using the Wilson, NRTL, and UNIQUAC equations for liquid phase activity coefficients and adequately predicted using the

Alberto Arce; J. Martinez-Ageitos; Ana Soto

1996-01-01

467

Self-Energy of the delta -Isobar in Nuclear Matter for the Paris and the Green-Niskanen-Sainio Potentials.  

National Technical Information Service (NTIS)

A coupled channel calculation, with the compensated Paris potential and the isobar transition potential due to Green, Niskanen and Sainio, yields the nucleon and isobar self-energies in nuclear matter. Unlike the Reid soft core, the Paris potential is fou...

J. Dey M. Abdul Matin B. C. Samanta

1985-01-01

468

Dislocation equilibrium conditions revisited  

Microsoft Academic Search

If there is an equilibrium arrangement of a given collection of dislocations, each having a fixed size and shape, in an externally loaded or unloaded elastic body, the corresponding potential energy will be stationary with respect to infinitesimal perturbations of the dislocation positions. This leads to the dislocation equilibrium conditions: the Peach–Koehler forces along the dislocation line of each dislocation

V. A. Lubarda

2006-01-01

469

Isobaric Heat Capacities of Natural Gases at Elevated Pressures and Temperatures  

Microsoft Academic Search

A new correlation has been developed for ideal isobaric heat capacity for natural gases. It is applicable over the temperature ranges of 32 less than or equal to T°F less than or equal to 2240 and 32 less than or equal to T°F less than or equal to 300 for sweet and sour gases respectively. In addition a new generalized

J. H. Abou-Kassem; P. M. Dranchuk

1982-01-01

470

Charge-changing cross sections near the {Delta}-isobar resonance  

SciTech Connect

Investigations of the charge-changing fragmentation cross sections for nuclei ranging from {sup 12}C to {sup 58}Ni and energy/nucleon from 300 to 2100 MeV on hydrogen emphasize the influence of nucleon isobar excitations. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Doll, P. [Kernforschungszentrum Karlsruhe, Institut fuer Kernphysik 1, P.O. Box 3640, D-76021 Karlsruhe (Germany); Crawford, H.J. [Space Science Laboratory, University of California, Berkeley, California 94720 (United States)

1995-02-05

471

Proton Particle-Neutron Quasiparticle Calculation of the Isobaric Analog Resonances of the Tin Isotopes  

Microsoft Academic Search

The response function method is extended to the case where the pairing correlation plays an important role. We use this theory to calculate the proton escape widths of the isobaric analog resonaces of the even tin isotopes. The calculated proton escape widths explain the mass dependence of the empirical widths.

Mitsuru Tohyama

1982-01-01

472

Binding Energies of the Alpha Particle and the A=3 Isobars from a Theoretical Geometric Model  

Microsoft Academic Search

We assume a triple geometric structure for the electromagnetic nuclear interaction. This nuclear electromagnetism is used to calculate the binding energies of the alpha particle and the A=3 isobar nuclides. The approximation for the resultant wave equation which lead to the deuteron binding energy from the modified Mathieu equation for the radial eigenvalue equation also establishes proton-electron-proton magnetic bonds in

Gustavo R. Gonzalez-Martin

2008-01-01

473

Binding Energies of the ? Particle and the A=3 Isobars from a Theoretical Geometric Model  

Microsoft Academic Search

We assume a triple geometric structure for the electromagnetic nuclear interaction. This nuclear electromagnetism is used to calculate the binding energies of the alpha particle and the A=3 isobar nuclides. The approximation for the resultant wave equation which lead to the deuteron binding energy from the modified Mathieu equation for the radial eigenvalue equation also establishes pro- ton-electron-proton magnetic bonds

Gustavo R. González-Martín

474

Joint horizontal-vertical anisotropic scaling, isobaric and isoheight wind statistics from aircraft data  

NASA Astrophysics Data System (ADS)

Aircraft measurements of the horizontal wind have consistently found transitions from roughly k-5/3 to k-2.4 spectra at scales ?xc ranging from about 100-500 km. Since drop sondes find k-2.4 spectra in the vertical, the simplest explanation is that the aircraft follow gently sloping trajectories (such as isobars) so that at large scales, they estimate vertical rather than horizontal spectra. In order to directly test this hypothesis, we used over 14500 flight segments from GPS and TAMDAR sensor equipped commercial aircraft. We directly estimate the joint horizontal-vertical (?x, ?z) wind structure function finding - for both longitudinal and transverse components - that the ratio of horizontal to vertical scaling exponents is Hz ? 0.57 ± 0.02, close to the theoretical prediction of the 23/9D turbulence model which predicts Hz = 5/9 = 0.555…. This model also predicts that isobars and isoheight statistics will diverge after ?xc; using the observed fractal dimension of the isobars (?1.79 ± 0.02), we find that the isobaric scaling exponents are almost exactly as predicted theoretically and ?xc ? 160, 125 km, (transverse, longitudinal). These results thus give strong direct support to the 23/9D scaling stratification model.

Pinel, J.; Lovejoy, S.; Schertzer, D.; Tuck, A. F.

2012-06-01

475

Isobaric analog states as a tool for spectroscopy of exotic nuclei  

Microsoft Academic Search

Spectroscopy of neutron rich exotic isotopes via their isobaric analog states (IAS) in less exotic nuclei is discussed. Several different experimental techniques, which can be applied to search for IAS of exotic isotopes, are described. Successful application of these techniques to the studies of heavy helium isotopes 7He and 9He led to the observation of unknown IAS in 7Li and

G. V. Rogachev; A. A. Aprahamian; F. D. Becchetti; P. Boutachkov; Y. Chen; G. Chubarian; P. A. DeYoung; A. Fomichev; V. Z. Goldberg; M. S. Golovkov; J. J. Kolata; Yu. Ts. Oganessian; G. F. Peaslee; M. Quinn; A. Rodin; B. B. Skorodumov; R. S. Slepnev; G. Ter-Akopian; W. H. Trzaska; A. Wohr; R. Wolski

2005-01-01

476

Quantification by isobaric labeling (QUIBL) for the comparative glycomic study of O-linked glycans  

NASA Astrophysics Data System (ADS)

Quantification by isobaric labeling (QUIBL) has recently been described as a tool for the relative quantification of N-linked glycans in glycomic studies. In this paper we expand the application of QUIBL to the relative quantification of O-linked glycans. Fetuin, which contains two O-linked glycans, NeuAc-Hex-HexNAc and NeuAc2-Hex-HexNAc, was used to validate this studyE The glycans were released by [beta]-elimination and permethylated with the isobaric labeling reagents, 13CH3I and 12CH2DI. The exact mass difference between the isobaric labels is minimal (0.00292 Da), but since glycans contain multiple permethylation sites, the mass difference can be resolved with a high resolution mass spectrometer, such as an FTMS. Quantitative data were obtained by comparing the signal intensities from various mixtures of isobarically labeled O-linked glycans of fetuin. Five different ratios of 13CH3 to 12CH2D ranging from 10:1 to 1:10 were analyzed for linearity and reproducibility of the QUIBL method on the standard glycan. QUIBL was also evaluated using porcine mucin, a sample with a larger variety of more complex O-linked glycans. These results indicate that QUIBL allows for the relative quantification of O-linked glycans over a linear dynamic range of at least two orders of magnitude, validating QUIBL as an applicable quantitative glycomics approach for both N-linked and O-linked glycans.

Botelho, Julianne Cook; Atwood, James A., III; Cheng, Lei; Alvarez-Manilla, Gerardo; York, William S.; Orlando, Ron

2008-12-01

477

Masses of proton-rich T/sub z/<0 nuclei via the isobaric mass equation  

SciTech Connect

Masses of T/sub z/<0 nuclei through the element Sm, corresponding to Aless than or equal to117, have been calculated with the isobaric multiplet mass equation using parameterizations of its constant b and T/sub z/>0 reference masses of Wapstra, Audi, and Hoekstra. copyright 1988 Academic Press, Inc.

Pape, A.; Antony, M.S.

1988-07-01

478

Direct Monte Carlo simulation of the chemical equilibrium composition of detonation products  

SciTech Connect

A new Monte Carlo simulation method has been developed by the author which gives the equilibrium chemical composition of a molecular fluid directly. The usual NPT ensemble (isothermal-isobaric) is implemented with N being the number of atoms instead of molecules. Changes in chemical composition are treated as correlated spatial moves of atoms. Given the interaction potentials between molecular products, ``exact`` EOS points including the equilibrium chemical composition can be determined from the simulations. This method is applied to detonation products at conditions in the region near the Chapman- Jouget state. For the example of NO, it is shown that the CJ detonation velocity can be determined to a few meters per second. A rather small change in cross potentials is shown to shift the chemical equilibrium and the CJ conditions significantly.

Shaw, M.S.

1993-06-01

479

Comparative study of intrathecal hyperbaric versus isobaric ropivacaine: A randomized control trial  

PubMed Central

Background: Hyperbaric ropivacaine produce more reliable sensory and motor block, with faster onset, better quality of muscles relaxation than isobaric ropivacaine. So, this study was designed to compare the efficacy of hyperbaric ropivacaine with isobaric ropivacaine in patients undergoing lower abdominal surgery. Methods: A randomized controlled double blind study in two groups of patients. group A (n=35) received 3 ml of isobaric ropivacaine 6 mg/ml (18 mg). Group B (n=35) received 3 ml of hyperbaric ropivacaine 6 mg/ml (18 mg). The onset and duration of sensory block at dermatome level T10, maximum upper and lower spread of sensory block, intensity, and duration of motor block were recorded. Statistical Analysis: Block characteristics were compared using the two-tailed Mann – Whitney U-test. The proportion of side effects was compared using the Chi-square test. Results: The median time of onset of sensory block at the T10 dermatome was 4.4±1.3 min in group B and 6.0±1.03 min in group A. The median time to maximum block height was 16.7±3.7 min in group A and 12.03±1.96 min in group B. The median duration of complete motor recovery (B0) was significantly shorter in the heavy ropivacaine group (166.5±11.7 min) compared with the isobaric ropivacaine group (192.9±9.6 min). Conclusions: Intrathecal hyperbaric ropivacaine provides more rapid, adequate, and good quality of sensory and motor block with rapid post-operative recovery as compare to isobaric ropivacaine.

Gupta, Rajni; Bogra, Jaishri; Singh, Prithvi Kumar; Saxena, Sulekha; Chandra, Girish; Kushwaha, Jitendra Kumar

2013-01-01

480

Non-equilibrium Thermodynamic Processes: Space Plasmas and the Inner Heliosheath  

NASA Astrophysics Data System (ADS)

Recently, empirical kappa distribution, commonly used to describe non-equilibrium systems like space plasmas, has been connected with non-extensive statistical mechanics. Here we show how a consistent definition of the temperature and pressure is developed for stationary states out of thermal equilibrium, so that the familiar ideal gas state equation still holds. In addition to the classical triplet of temperature, pressure, and density, this generalization requires the kappa index as a fourth independent thermodynamic variable that characterizes the non-equilibrium stationary states. All four of these thermodynamic variables have key roles in describing the governing thermodynamical processes and transitions in space plasmas. We introduce a novel characterization of isothermal and isobaric processes that describe a system's transition into different stationary states by varying the kappa index. In addition, we show how the variation of temperature or/and pressure can occur through an "iso-q" process, in which the system remains in a fixed stationary state (fixed kappa index). These processes have been detected in the proton plasma in the inner heliosheath via specialized data analysis of energetic neutral atom (ENA) observations from Interstellar Boundary Explorer. In particular, we find that the temperature is highly correlated with (1) kappa, asymptotically related to isothermal (~1,000,000 K) and iso-q (? ~ 1.7) processes; and (2) density, related to an isobaric process, which separates the "Ribbon," P ? 3.2 pdyn cm-2, from the globally distributed ENA flux, P ? 2 pdyn cm-2.

Livadiotis, G.; McComas, D. J.

2012-04-01

481

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: III. Vapor-liquid water equilibration of NaCl solutions to 350°C  

NASA Astrophysics Data System (ADS)

The effect of dissolved NaCl on equilibrium oxygen and hydrogen isotope fractionation factors between liquid water and water vapor was precisely determined in the temperature range from 130-350°C, using two different types of apparatus with static or dynamic sampling techniques of the vapor phase. The magnitude of the oxygen and hydrogen isotope effects of NaCl is proportional to the molality of liquid NaCl solutions at a given temperature. Dissolved NaCl lowers appreciably the hydrogen isotope fractionation factor between liquid water and water vapor over the entire temperature range. NaCl has little effect on the oxygen isotope fractionation factor at temperatures below about 200°C, with the magnitude of the salt effect gradually increasing from 200-350°C. Our results are at notable variance with those of Truesdell (1974) and Kazahaya (1986), who reported large oxygen and hydrogen isotope effects of NaCl with very complex dependencies on temperature and NaCl molality. Our high-temperature results have been regressed along with our previous results between 50 and 100°C (Horita et al., 1993a) and the low-temperature literature data to simple equations which are valid for NaCl solutions from 0 to at least 5 molal NaCl in the temperature range from 10-350°C. Our preliminary results of oxygen isotope fractionation in the system CaCO 3-water ± NaCl at 300°C and 1 kbar are consistent with those obtained from the liquid-vapor equilibration experiments, suggesting that the isotope salt effects are common to systems involving brines and any other coexisting phases or species (gases, minerals, dissolved species, etc.). The observed NaCl isotope effects at elevated temperatures should be taken into account in the interpretation of isotopic data of brine-dominated natural systems.

Horita, Juske; Cole, David R.; Wesolowski, David J.

1995-03-01

482

Response reactions: equilibrium coupling.  

PubMed

It is pointed out and illustrated in the present paper that if a homogeneous multiple equilibrium system containing k components and q species is composed of the reactants actually taken and their reactions contain only k + 1 species, then we have a unique representation with (q - k) stoichiometrically independent reactions (SIRs). We define these as coupling reactions. All the other possible combinations with k + 1 species are the coupled reactions that are in equilibrium when the (q - k) SIRs are in equilibrium. The response of the equilibrium state for perturbation is determined by the coupling and coupled equilibria. Depending on the circumstances and the actual thermodynamic data, the effect of coupled equilibria may overtake the effect of the coupling ones, leading to phenomena that are in apparent contradiction with Le Chatelier's principle. PMID:16722770

Hoffmann, Eufrozina A; Nagypal, Istvan

2006-06-01

483

Trace Element Equilibrium Studies.  

National Technical Information Service (NTIS)

The equilibrium distribution coefficients of trace elements in seawater on ion-exchange resins were investigated. These resins contained various organic complexing and precipitating agents known to react with the elements under study. The resins used were...

J. D. Gassaway

1973-01-01

484

The activity-composition relationship of oxygen and hydrogen isotopes in aqueous salt solutions: II. Vapor-liquid water equilibration of mixed salt solutions from 50 to 100[degrees]C and geochemical implications  

SciTech Connect

The difference between oxygen and hydrogen isotope activity and composition ratios of water in mixed salt solutions in the system Na-K-Mg-Ca-Cl-SO[sub 4]-H[sub 2]O was determined by means of a vapor-liquid water equilibration method over the temperature range of 50 to 100[degrees]C. The observed isotope salt effects in complex mixed salt solutions to very high ionic strengths agree quantitatively with calculations based on the assumption of a simple additive property of the isotope salt effects of the individual salts in the solutions. Sofer and Gat (1972, 1975) and Horita and Gat (1989) also observed that this simple mixing rule applies to synthetic and natural chloride-mixed salt solutions at room temperature. Equations to convert between the isotope activity and composition scales for brines and fractionation factors between brines and other substances are presented. For most geochemical interactions between brines and other phases (vapor, gases, minerals), such as evaporation/boiling, mineral precipitation, and mineral/rock alteration, the isotope activity scale should be used. The isotope composition scale, on the other hand, is most useful for studies of mixing of different brines and formation of brines by mineral dissolution. Misusage of the two isotopic scales of brines will, and probably in the literature has, lead to incorrect conclusions in many isotopic studies of brine-dominated systems (origin of brines, temperature of mineral formation, isotope ratios of fossil fluids).

Horita, J.; Cole, D.R.; Wesolowski, D.J. (Oak Ridge National Lab., TN (United States))

1993-10-01

485

Nonisothermal filaments in equilibrium  

NASA Astrophysics Data System (ADS)

Context. The physical properties of the so-called Ostriker isothermal filament have been classically used as a benchmark to interpret the stability of the filaments observed in nearby clouds. However, recent continuum studies have shown that the internal structure of the filaments depart from the isothermality, typically exhibiting radially increasing temperature gradients. Aims: The presence of internal temperature gradients within filaments suggests that the equilibrium configuration of these objects should be therefore revisited. The main goal of this work is to theoretically explore how the equilibrium structure of a filament changes in a nonisothermal configuration. Methods: We solve the hydrostatic equilibrium equation by assuming temperature gradients similar to those derived from observations. Results: We obtain a new set of equilibrium solutions for nonisothermal filaments with both linear and asymptotically constant temperature gradients. For sufficiently large internal temperature gradients, our results show that a nonisothermal filament could present significantly larger masses per unit length and shallower density profiles than the isothermal filament without collapsing by its own gravity. Conclusions: We conclude that filaments can reach an equilibrium configuration under nonisothermal conditions. Detailed studies of both the internal mass distribution and temperature gradients within filaments are then needed to judge the physical state of filaments.

Recchi, S.; Hacar, A.; Palestini, A.

2013-10-01

486

Gas-phase ion-molecule reactions for resolution of atomic isobars: AMS and ICP-MS perspectives  

Microsoft Academic Search

Ion-molecule reactions that can be used for resolution of spectral overlaps of long-lived or stable (T1\\/2 > 100 years) atomic isobars on the long-lived radio-isotopes (100 < T1\\/2 < 1012 years) in mass spectrometry are considered. Results for the separations of isobaric overlaps via cation reactions with NO, N2O, O2, CO2, C2H2, CH3F studied with the Inductively Coupled Plasma Dynamic

Dmitry R. Bandura; Vladimir I. Baranov; A. E. Litherland; Scott D. Tanner

2006-01-01

487

Isobars of an ideal Bose gas within the grand canonical ensemble  

SciTech Connect

We investigate the isobar of an ideal Bose gas confined in a cubic box within the grand canonical ensemble for a large yet finite number of particles, N. After solving the equation of the spinodal curve, we derive precise formulas for the supercooling and the superheating temperatures that reveal an N{sup -1/3} or N{sup -1/4} power correction to the known Bose-Einstein condensation temperature in the thermodynamic limit. Numerical computations confirm the accuracy of our analytical approximation, and further show that the isobar zigzags on the temperature-volume plane if N{>=}14 393. In particular, for the Avogadro's number of particles, the volume expands discretely about 10{sup 5} times. Our results quantitatively agree with a previous study on the canonical ensemble within 0.1% error.

Jeon, Imtak; Park, Jeong-Hyuck [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Kim, Sang-Woo [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

2011-08-15

488

Measurements of the Isobaric Specfic Heat Capacity of Refrigerant 13B1 in the Gaseous Region  

NASA Astrophysics Data System (ADS)

The isobaric specific heat capacity of Refrigerant 13B1 (CBrF3) has been measured by the flow calorimeter. Thirty-four measurements were obtained in the gaseous region for temperatures 283 to 383 K up to 3 MPa including the region near the saturation line. The sample purity used was 99.99 wt%. The uncertainty of the measurements was estimated to be less than 1.3% and the reproducibility has been confirmed to be less than 0.7%. The present results reveal the bahavior of the isobaric specific heat capacity of R 13B1 in the gaseous region. The present results were compared with the values calculated by the available equations of state. The comparison shows that no equation of state describes the present results with satisfactory accuracy.

Kigami, Toru; Saegusa, Shogo; Uematsu, Masahiko; Watanabe, Koichi

489

Determination of nonaxisymmetric equilibrium  

SciTech Connect

The Princeton Equilibrium Code is modified to determine the equilibrium surfaces for a large aspect ratio toroidal system with helical magnetic fields. The code may easily be made to include any variety of modes. Verification of the code is made by comparison with an analytic solution for l = 3. Previously observed shifting of the magnetic axis with increasing pressure or with a changed externally applied vertical field is obtained. The case l = 0, a bumpy torus, gives convergence only for the lenient convergence tolerance of epsilon/sub b/ = 1.0 x 10-/sup 2/.

Elkin, D.

1980-01-01

490

Beyond Equilibrium Thermodynamics  

NASA Astrophysics Data System (ADS)

Beyond Equilibrium Thermodynamics fills a niche in the market by providing a comprehensive introduction to a new, emerging topic in the field. The importance of non-equilibrium thermodynamics is addressed in order to fully understand how a system works, whether it is in a biological system like the brain or a system that develops plastic. In order to fully grasp the subject, the book clearly explains the physical concepts and mathematics involved, as well as presenting problems and solutions; over 200 exercises and answers are included. Engineers, scientists, and applied mathematicians can all use the book to address their problems in modelling, calculating, and understanding dynamic responses of materials.

Öttinger, Hans Christian

2005-01-01

491

Multiplexed Protein Quantitation in Saccharomyces cerevisiae Using Amine-reactive Isobaric Tagging Reagents  

Microsoft Academic Search

We describe here a multiplexed protein quantitation strat- egy that provides relative and absolute measurements of proteins in complex mixtures. At the core of this method- ology is a multiplexed set of isobaric reagents that yield amine-derivatized peptides. The derivatized peptides are indistinguishable in MS, but exhibit intense low-mass MS\\/MS signature ions that support quantitation. In this study, we have

Philip L. Ross; Yulin N. Huang; Jason N. Marchese; Brian Williamson; Kenneth Parker; Stephen Hattan; Nikita Khainovski; Sasi Pillai; Subhakar Dey; Scott Daniels; Subhasish Purkayastha; Peter Juhasz; Stephen Martin; Michael Bartlet-Jones; Feng He; Allan Jacobson; Darryl J. Pappin

2004-01-01

492

Binding Energies of the Alpha Particle and the A=3 Isobars from a Theoretical Geometric Model  

Microsoft Academic Search

We assume a triple geometric structure for the electromagnetic nuclear\\u000ainteraction. This nuclear electromagnetism is used to calculate the binding\\u000aenergies of the alpha particle and the A=3 isobar nuclides. The approximation\\u000afor the resultant wave equation which lead to the deuteron binding energy from\\u000athe modified Mathieu equation for the radial eigenvalue equation also\\u000aestablishes proton-electron-proton magnetic bonds in

Gustavo R. Gonzalez-Martin

2008-01-01

493

Structure of heavy helium isotopes via the isobaric analog states in Lithium  

Microsoft Academic Search

Study of nuclei far removed from the valley of stability provide an opportunity to test the models of nuclear structure. In particular, heavy isotopes of helium attract much attention due to their extreme neutron to proton ratio. In this work we studied the T=5\\/2 states in ^9Li and T=3\\/2 states in ^7Li, isobaric analog states of ^9He and ^7He respectively.

G. V. Rogachev; A. Aprahamian; P. Boutachkov; M. Quinn; J. J. Kolata; B. Skorodumov; A. Woehr; V. Z. Goldberg; G. Chubarian; A. Fomichev; M. S. Golovkov; Yu. Ts. Oganessian; A. Rodin; R. S. Slepnev; G. Ter-Akopian; R. Wolski; W. H. Trzaska; D. V. Aleksandrov; P. A. Deyoung; G. F. Peaslee; P. J. Mears; F. D. Becchetti; Y. Chen

2003-01-01

494

Correlation of structural and Johari Goldstein relaxations in systems vitrifying along isobaric and isothermal paths  

Microsoft Academic Search

The effect of isobaric cooling (over the range 190-350 K) and isothermal compression (up to 700 MPa) on structural alpha- and secondary beta-relaxations has been studied for low molecular weight glass-forming systems. The shape of the alpha-loss peak was found to change with temperature T and pressure P but to be constant for a combination of T and P giving

S. Capaccioli; K. Kessairi; D. Prevosto; M. Lucchesi; P. A. Rolla

2007-01-01

495