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

International Nuclear Information System (INIS)

Fu Jinxia; Suuberg, Eric M.

2011-01-01

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

Estimated vapor pressure for WTP process streams

Energy Technology Data Exchange (ETDEWEB)

Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-01-01

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

The vaporization enthalpy and vapor pressure of S (+)-methamphetamine at T = 298.15 K by correlation gas chromatography

International Nuclear Information System (INIS)

Thornton, Melissa; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpy of (d)-methamphetamine was measured. • The vapor pressure of (d)-methamphetamine as a function of temperature was evaluated. • The vapor pressure of 4-benzylpiperidine as a function of temperature was evaluated. - Abstract: The vaporization enthalpy and vapor pressure of S (+)-methamphetamine is evaluated by correlation-gas chromatography. A vaporization enthalpy of (58.7 ± 4.3) kJ · mol −1 and a vapor pressure, p = (38 ± 9) Pa has been obtained using a variety of secondary aliphatic amines as standards. In addition, equations describing the vapor pressure temperature dependence are provided for standards and S (+)-methamphetamine covering the temperature range from T = 298.15 K to the boiling temperature. Boiling temperatures are reproduced within an interval of 8 K or less

Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

Energy Technology Data Exchange (ETDEWEB)

Goldfarb, Jillian L., E-mail: JillianLGoldfarb@gmail.co [Division of Engineering, Brown University, Providence, RI 02912 (United States); Suuberg, Eric M., E-mail: Eric_Suuberg@brown.ed [Division of Engineering, Brown University, Providence, RI 02912 (United States)

2010-06-15

The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) g . mol{sup -1} were measured over the temperature range of (301 to 486) K using the isothermal Knudsen effusion technique. The compounds measured include: anthraquinone, 9-fluorenone, 9-fluorenone oxime, phenoxazine, phenoxathiin, and 9H-pyrido[3,4-b]indole. These solid-state sublimation measurements provided values that are compared to vapor pressures of parent aromatic compounds (anthracene and fluorene) and to others with substituent groups in order to examine the effects of alcohol, ketone, pyridine, and pyrrole functionality on this property. The enthalpies and entropies of sublimation for each compound were determined from the Clausius-Clapeyron equation. Though there is no consistent trend in terms of the effects of substitutions on changes in the enthalpy or entropy of sublimation, we note that the prevalence of enthalpic or entropic driving forces on vapor pressure depend on molecule-specific factors and not merely molecular weight of the substituents.

The vapor pressure and enthalpy of vaporization of M-xylene

International Nuclear Information System (INIS)

Rothenberg, S.J.; Seiler, F.A.; Bechtold, W.E.; Eidson, A.F.

1988-01-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 ± 0.1 (SE) kj/ g·mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 (± 0.1) (SE) kjg·mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization (ΔCpdeg.) of 35 ± 3 (SE) J/g·mol·K over the temperature range studied. (author)

Vapor pressures and vaporization enthalpy of (−) α-bisabolol and (dl) menthol by correlation gas chromatography

International Nuclear Information System (INIS)

Keating, Leasa; Harris, Harold H.; Chickos, James S.

2017-01-01

Highlights: • The vaporization enthalpy and vapor pressure of (−) α-bisabolol and (dl)-menthol have been measured as a function of temperature. • Vapor pressures, vaporization enthalpies and boiling temperatures have been compared to available literature data. • Vapor pressures of (l)-menthol are compared to (dl)-menthol. - Abstract: The vapor pressures and vaporization enthalpies of (−) α-bisabolol and (dl)-menthol, two GRAS chemicals (generally recognized as safe) are evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. Vaporization enthalpies of (96.6 ± 2.4) and (74.2 ± 2.8) kJ mol −1 and vapor pressures of p/Pa = (0.020 ± 0.003) and (4.5 ± 0.44) were evaluated at T = 298.15 K for (−) α-bisabolol and (dl)-menthol, respectively, and compared to literature values. The vapor pressures of both compounds from T = (298.15 to 500) K have been derived from correlations using vapor pressures of a series of 1-alkanols and corresponding gas chromatographic retention times at 10 K intervals. The results were fit to a second order polynomial. Calculated normal boiling temperatures of T B = (574.8 and 492.7) K are calculated for (−) α-bisabolol and (dl)-menthol, respectively. A normal boiling temperature of T B = (485.2, and 489.7) K has previously been reported for (dl)-menthol. Vapor pressures for both (l)-menthol and (dl)-menthol from a previous study and (dl)-menthol from this study are compared with literature values.

Vapor Pressure Data Analysis and Statistics

Science.gov (United States)

2016-12-01

near 8, 2000, and 200, respectively. The A (or a) value is directly related to vapor pressure and will be greater for high vapor pressure materials...1, (10) where n is the number of data points, Yi is the natural logarithm of the i th experimental vapor pressure value, and Xi is the...VAPOR PRESSURE DATA ANALYSIS AND STATISTICS ECBC-TR-1422 Ann Brozena RESEARCH AND TECHNOLOGY DIRECTORATE

Melting temperature, vapor density, and vapor pressure of molybdenum pentafluoride

Energy Technology Data Exchange (ETDEWEB)

Krause, Jr, R F; Douglas, T B [National Bureau of Standards, Washington, D.C. (USA). Inst. for Materials Research

1977-12-01

A sample of MoF/sub 5/ was prepared by reaction of MoF/sub 6/(g) and Mo(c). Melting curves of temperature against time established the melting temperature at zero impurity to be 318.85 K, the enthalpy of fusion to be 6.1 kJ mol/sup -1/ (+ - 5 per cent), and the cryoscopic impurity of the sample to be 0.15 mole per cent. In the presence of MoF/sub 6/(g) which was added to suppress disproportionation, the vapor density of MoF/sub 5/ over the liquid was measured by the transpiration method at 343, 363, and 383 K, the total MoF/sub 5/ that evaporated being determined by permanganate titration. The total vapor pressure of MoF/sub 5/ oligomers over the liquid was measured by a simple static method at 373 and 392 K, while melting temperatures were taken alternately to monitor possible contamination of the sample. Although the vapor pressures were adjusted for disproportionation, solution of MoF/sub 6/ in MoF/sub 5/ (1), and wall adsorption of MoF/sub 6/ their percentage uncertainty is probably several times that of the vapor densities. A combination of the two properties indicates the average extent of association of the saturated vapor to be near 2, which is the value for the dimer species (MoF/sub 5/)/sub 2/.

Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO2 + alkanol) binary systems

International Nuclear Information System (INIS)

Bejarano, Arturo; Gutierrez, Jorge E.; Araus, Karina A.; Fuente, Juan C. de la

2011-01-01

Research highlights: → (Vapor + liquid) equilibria of three (CO 2 + C 5 alcohol) binary systems were measured. → Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. → No liquid immiscibility was observed at the temperatures and pressures studied. → Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. → Correlation results showed relative deviations ≤8 % (liquid) and ≤2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO 2 + 3-methyl-2-butanol), (CO 2 + 2-pentanol), and (CO 2 + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO 2 + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

Vapor pressure and thermodynamics of beryllium carbide

International Nuclear Information System (INIS)

Rinehart, G.H.; Behrens, R.G.

1980-01-01

The vapor pressure of beryllium carbide has been measured over the temperature range 1388 to 1763 K using Knudsen-effusion mass spectrometry. Vaporization occurs incongruently according to the reaction Be 2 C(s) = 2Be(g) + C(s). The equilibrium vapor pressure above the mixture of Be 2 C and C over the experimental temperature range is (R/J K -1 mol -1 )ln(p/Pa) = -(3.610 +- 0.009) x 10 5 (K/T) + (221.43 +- 1.06). The third-law enthalpy change for the above reaction obtained from the present vapor pressures is ΔH 0 (298.15 K) = (740.5 +- 0.1) kJ mol -1 . The corresponding second-law result is ΔH 0 (298.15 K) = (732.0 +- 1.8) kJ mol -1 . The enthalpy of formation for Be 2 C(s) calculated from the present third-law vaporization enthalpy and the enthalpy of formation of Be(g) is ΔH 0 sub(f)(298.15 K) = -(92.5 +- 15.7) kJ mol -1 . (author)

The vapor pressure and enthalpy of vaporization of M-xylene

Energy Technology Data Exchange (ETDEWEB)

Rothenberg, S J; Seiler, F A; Bechtold, W E; Eidson, A F

1988-12-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 {+-} 0.1 (SE) kj/ g{center_dot}mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 ({+-} 0.1) (SE) kjg{center_dot}mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization ({delta}Cpdeg.) of 35 {+-} 3 (SE) J/g{center_dot}mol{center_dot}K over the temperature range studied. (author)

Vapor pressures and vaporization enthalpy of codlemone by correlation gas chromatography

International Nuclear Information System (INIS)

Schultz, Shannon M.; Harris, Harold H.; Chickos, James S.

2015-01-01

Highlights: • The vaporization enthalpy of codlemone has been evaluated. • The vapor pressure of codlemone has been evaluated from T = (298.15 to T b ) K. • Vapor pressures for the 1-alkanols standards are available from T = (298.15 to 500) K. - Abstract: The vapor pressure and vaporization enthalpy of codlemone (trans, trans 8,10-dodecadien-1-ol), the female sex hormone of the codling moth is evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. A vaporization enthalpy of (92.3 ± 2.6) kJ · mol −1 and a vapor pressure, p/Pa = (0.083 ± 0.012) were evaluated at T = 298.15 K. An equation for the evaluation of vapor pressure from ambient temperature to boiling has been derived by correlation for codlemone. The calculated boiling temperature of T B = 389 K at p = 267 Pa is within the temperature range reported in the literature. A normal boiling temperature of T B = (549.1 ± 0.1) K is also estimated by extrapolation

Measurement and modeling of high-pressure (vapor + liquid) equilibria of (CO{sub 2} + alkanol) binary systems

Energy Technology Data Exchange (ETDEWEB)

Bejarano, Arturo; Gutierrez, Jorge E. [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Araus, Karina A. [Departamento de Ingenieria Quimica y Bioprocesos, Pontificia Universidad Catolica de Chile, Avda. Vicuna Mackenna 4860, Macul, Santiago (Chile); Fuente, Juan C. de la, E-mail: juan.delafuente@usm.c [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Centro Regional de Estudios en Alimentos Saludables, Blanco 1623, Valparaiso (Chile)

2011-05-15

Research highlights: (Vapor + liquid) equilibria of three (CO{sub 2} + C{sub 5} alcohol) binary systems were measured. Complementary data are reported at (313, 323 and 333) K and from (2 to 11) MPa. No liquid immiscibility was observed at the temperatures and pressures studied. Experimental data were correlated with the PR-EoS and the van de Waals mixing rules. Correlation results showed relative deviations {<=}8 % (liquid) and {<=}2 % (vapor). - Abstract: Complementary isothermal (vapor + liquid) equilibria data are reported for the (CO{sub 2} + 3-methyl-2-butanol), (CO{sub 2} + 2-pentanol), and (CO{sub 2} + 3-pentanol) binary systems at temperatures of (313, 323, and 333) K, and at pressure range of (2 to 11) MPa. For all (CO{sub 2} + alcohol) systems, it was visually monitored that there was no liquid immiscibility at the temperatures and pressures studied. The experimental data were correlated with the Peng-Robinson equation of state using the quadratic mixing rules of van der Waals with two adjustable parameters. The calculated (vapor + liquid) equilibria compositions were found to be in good agreement with the experimental data with deviations for the mole fractions <8% and <2% for the liquid and vapor phase, respectively.

Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {1,1,1,2-tetrafluoroethane (R134a) + propane (R290)} by a recirculation apparatus with view windows

International Nuclear Information System (INIS)

Dong Xueqiang; Gong Maoqiong; Liu Junsheng; Wu Jianfeng

2011-01-01

The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than ±5 mK, ±0.0005 MPa, and ±0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

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

Science.gov (United States)

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

2018-05-01

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

Vapor pressures and sublimation enthalpies of novel bicyclic heterocycle derivatives

International Nuclear Information System (INIS)

Blokhina, Svetlana V.; Ol’khovich, Marina V.; Sharapova, Angelica V.; Perlovich, German L.; Proshin, Alexey N.

2014-01-01

Highlights: • The vapor pressures of novel bicyclo-derivatives of amine were measured. • Thermodynamic functions of sublimation were calculated. • The influence of substituent structure and chemical nature on the vapor pressure was studied. -- Abstract: The vapor pressures of five novel bicyclic heterocycle derivatives were measured over the temperature 341.15 to 396.15 K using the transpiration method by means of an inert gas carrier. From these results the standard enthalpies and Gibbs free energies of sublimation at the temperature 298.15 K were calculated. The effects of alkyl- and chloro-substitutions on changes in the thermodynamic functions have been investigated. Quantitative structure–property relationship on the basis HYBOT physico-chemical descriptors for biologically active compounds have been developed to predict the sublimation enthalpies and Gibbs free energies of the compounds studied

Density, viscosity, and saturated vapor pressure of ethyl trifluoroacetate

International Nuclear Information System (INIS)

Huang, Zhixian; Jiang, Haiming; Li, Ling; Wang, Hongxing; Qiu, Ting

2015-01-01

Highlights: • Density of ethyl trifluoroacetate was measured and its thermal expansion coefficient was determined. • Viscosity of ethyl trifluoroacetate was measured and fitted to the Andrade equation. • Saturated vapor pressure of ethyl trifluoroacetate was reported. • The Clausius–Clapeyron equation was used to calculate the molar evaporation enthalpy of ethyl trifluoroacetate. - Abstract: The properties of ethyl trifluoroacetate (CF 3 COOCH 2 CH 3 ) were measured as a function of temperature: density (278.08 to 322.50) K, viscosity (293.45 to 334.32) K, saturated vapor pressure (293.35 to 335.65) K. The density data were fitted to a quadratic polynomial equation, and the viscosity data were regressed to the Andrade equation. The correlation coefficient (R 2 ) of equations for density and viscosity are 0.9997 and 0.9999, respectively. The correlation between saturated vapor pressures and temperatures was achieved with a maximum absolute relative deviation of 0.142%. In addition, the molar evaporation enthalpy in the range of T = (293.35 to 335.65) K was estimated by the Clausius–Clapeyron equation

Measurement and analysis of transient vaporization in oxide fuel materials

International Nuclear Information System (INIS)

Gorham-Bergeron, E.; Benson, D.A.

1978-01-01

A series of experiments is described in which samples are heated to produce high vapor pressure states in times of 10 -6 to 10 -3 seconds. Experimental measurements of vapor pressures over fresh UO 2 from the pulsed electron beam and pulsed reactor heating tests are presented and compared with other high temperature data. The interpretation of the vapor pressures measured in the tests is discussed in detail. Effects of original sample stoichiometry, chemical interactions with the container and non-equilibrium evaporation due to induced temperature gradients are discussed. Special attention is given to dynamic behavior in rapid heating and vaporization of the oxide due to chemical nonequilibrium. Finally, similar projected reactor experiments on irradiated fuel are described and vapor pressure predictions made using available equilibrium models. A discussion of information accessible from such future tests and its importance is presented

Modified swelling pressure apparatus using vapor pressure technique for compacted bentonite

International Nuclear Information System (INIS)

Nishimura, Tomoyoshi

2012-01-01

Document available in extended abstract form only. bentonite. The compacted bentonite is found in unsaturated conditions before applying of swelling due to absorption. The behaviour of compacted bentonite is not consistent with the principle and concepts of classical, saturated soil mechanics. An unsaturated soil theoretical framework using soil water characteristic curve has been fairly established over the past several decades. The soil-water characteristic curve is a relationship between soil moisture and soil suction obtained by the axis translation technique, vapor pressure technique or osmotic suction control which is a key feature in unsaturated soil mechanics. The soil-water characteristic curve can be used for prediction of the shear strength, volume change and hydraulic conductivity. Cui et al. 2002 indicated soil-water characteristic curve of expansive clay soil in high soil suction ranges using osmotic suction technique. Tripathy et al. 2010 described the soil-water characteristic curve both using the axis translation technique and vapor pressure technique in the entire soil suction ranges. Nishimura and Koseki 2011 measured suction of bentonite applied high soil suction due vapor pressure using a chilled mirror dew point potentiometer (WP4-T of DECAGON Device). The bentonite with gravimetric water content of 18 % indicated soil suction of 2.8 MPa at least. It is predicted that suction efforts to swelling pressure and shear strength of unsaturated compacted bentonite. This study focuses on the influence of suction on both swelling pressure and shear strength of compacted bentonite. The soil-water characteristic curve (SWCC) tests were conducted for compacted bentonite using both axis-translation technique and vapor pressure technique. The SWCC had a range from 0 kPa to 296 MPa in suction. The compacted bentonite having two different soil suctions were prepared for swelling pressure tests. Newly swelling pressure testing apparatus was developed in order

Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {l_brace}1,1,1,2-tetrafluoroethane (R134a) + propane (R290){r_brace} by a recirculation apparatus with view windows

Energy Technology Data Exchange (ETDEWEB)

Dong Xueqiang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Gong Maoqiong, E-mail: gongmq@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Liu Junsheng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Wu Jianfeng, E-mail: jfwu@mail.ipc.ac.c [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, Beijing 100190 (China)

2011-03-15

The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than {+-}5 mK, {+-}0.0005 MPa, and {+-}0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng-Robinson equation of state (PR EoS) incorporating the Huron-Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.

Enthalpy of vaporization and vapor pressure of whiskey lactone and menthalactone by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Chickos, James

2017-01-01

Highlights: • The vapor pressure and vaporization enthalpies of cis and trans-whiskey lactone have been evaluated. • Enthalpies of vaporization and vapor pressures of (+)-isomintlactone and (−)-mintlactone were also evaluated. • The sublimation enthalpy and corresponding vapor pressure of (+) -isomintlactone at T = 298.15 K is estimated. - Abstract: Enthalpies of vaporization at T = 298.15 K of cis and trans-whiskey lactone have been evaluated by correlation gas chromatography to be (68.4 ± 1.7) kJ·mol −1 and (67.5 ± 1.7) kJ·mol −1 , respectively. The enthalpies of vaporization of isomintlactone and mintlactone also evaluated by correlation gas chromatography have been found to have vaporization enthalpies of (74.2 ± 1.8) kJ·mol −1 and (73.2 ± 1.8) kJ·mol −1 respectively. The vapor pressures for cis and trans-whiskey lactone at T = 298.15 K have been evaluated as (1.5 ± 0.09) Pa and (2.0 ± 0.1) Pa using vapor pressures of a series of lactones as standards. Vapor pressures for isomintlactone and mintlactone were evaluated as (0.26 ± 0.012) Pa and (0.33 ± 0.02) Pa, respectively. Fusion and sublimation enthalpies for (+)-isomintlactone as well as the vapor pressure of the solid have been estimated.

Measurement and analysis of transient vaporization in oxide fuel materials

International Nuclear Information System (INIS)

Benson, D.A.; Bergeron, E.G.

1979-01-01

This paper describes a series of experiments in which samples are heated to produce high vapor pressure states in times of 10 -6 to 10 -3 seconds. Experimental measurements of vapor pressures over fresh UO 2 from the pulsed electron beam and pulsed reactor heating tests are presented and compared with other high temperature data. The interpretation of the vapor pressure measured in the tests is discussed in detail. Effects of original sample stoichiometry, chemical interactions with the container and non-equilibrium evaporation due to induced temperature gradients are discussed. Special attention is given to dynamic behavior in rapid heating and vaporization of the oxide due to chemical non-equilibrium. Finally, similar projected reactor experiments on irradiated fuel are described and vapor pressure predictions made using available equilibrium models. A discussion of information accessible from such future tests and its importance is presented. (orig.) [de

Vapor pressure and enthalpy of vaporization of oil of catnip by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Gobble, Chase; Chickos, James

2016-01-01

Highlights: • Vaporization enthalpies of the nepetalactones from oil of catnip have been evaluated. • Vapor pressures from T = (298.15 to 350) K have been evaluated. • Oil of catnip has a vapor pressure similar to DEET at T = 298.15 K. - Abstract: The vaporization enthalpy and vapor pressure of the two nepetalactones found in Nepeta cataria have been evaluated by correlation gas chromatography. Vaporization enthalpies at T = 298.15 K of {(68.0 ± 1.9) and (69.4 ± 1.9)} kJ ⋅ mol"−"1 have been derived for the minor diastereomer, (4aS,7S,7aS)-nepetalactone, and major one, (4aS,7S,7aR)-nepetalactone, respectively. Vapor pressures also at T = 298.15 K of p = (1.2 ± 0.04) Pa and (0.91 ± 0.03) Pa have been evaluated for the minor and the major stereoisomer. In addition to being of interest because of the remarkable effect it has on various felids, oil of catnip is also quite effective in repelling mosquitoes, comparable to diethyl-m-toluamide (DEET). The vapor pressures evaluated in this work suggest that the two stereoisomers have similar volatility to DEET at ambient temperatures.

Vapor Pressure Measurements of LiBH4, NaBH 4 and Ca(BH4)2 using Knudsen Torsion Effusion Gravimetric Method

Science.gov (United States)

Danyan, Mohammad Masoumi

Hydrogen storage is one of the critical technologies needed on the path towards commercialization for mobile applications. In the past few years, a range of new light weight hydrogen containing material has been discovered with good storage properties. Among them, lithium borohydride (LiBH 4) sodium borohydride (NaBH4) and calcium borohydride (Ca(BH 4)2) have shown promising results to be used as solid state hydrogen storage material. In this work, we have determined equilibrium vapor pressures of LiBH 4 NaBH4 and Ca(BH4)2 obtained by Torsion effusion thermogravimetric method. Results for all the three hydrides exhibited that a small fraction of the materials showed congruency, and sublimed as gaseous compound, but the majority of the material showed incongruent vaporization. Two Knudsen cells of 0.3 and 0.6mm orifice size was employed to measure the total vapor pressures. A Whitman-Motzfeldt method is used to extrapolate the measured vapor pressures to zero orifice size to calculate the equilibrium vapor pressures. In the case of LiBH4 we found that 2% of the material evaporated congruently (LiBH4(s) → LiBH4(g)) according to the equation: logPLiBH4/P 0 =-3263.5 +/-309/T + (1.079 +/-0.69) and rest as incongruent vaporization to LiH, B, and hydrogen gas according to the equation logPeq/P0 =(-3263.5 +/-309)/T+ (2.458 +/-0.69) with DeltaH evap.= 62.47+/-5.9 kJ/mol of H2, DeltaSevap. = 47.05+/-13 J/mol of H2.K. The NaBH4 also had somewhat similar behavior, with 9% congruent evaporation and equilibrium vapor pressure equation of logPLiBH4=-7700+/-335/ T+ (6.7+/-1.5) and 91% incongruent decomposition to Na and Boron metal, and hydrogen gas. The enthalpy of vaporization; DeltaHevap. = 147.2+/-6.4kJ/molH2 and DeltaSevap.= 142 +/-28 kJ/molH2.K (550-650K). The Ca(BH4) 2 exhibited similar vaporization behavior with congruency of 3.2%. The decomposition products are CaH2 and Boron metal with evolution of hydrogen gas varying with the pressure equation as logPeq /P0 =(-1562

Vapor Pressure of Antimony Triiodide

Science.gov (United States)

2017-12-07

unlimited. iii Contents List of Figures iv 1. Introduction 1 2. Vapor Pressure 1 3. Experiment 3 4. Discussion and Measurements 5 5...SbI3 as a function of temperature ......................... 6 Approved for public release; distribution is unlimited. 1 1. Introduction ...single-crystal thin films of n-type (Bi,Sb)2(Te,Se)3 materials presents new doping challenges because it is a nonequilibrium process. (Bi,Sb)2(Te,Se)3

Evaporation rate and vapor pressure of selected polymeric lubricating oils.

Science.gov (United States)

Gardos, M. N.

1973-01-01

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

Vapor pressures and thermophysical properties of selected hexenols and recommended vapor pressure for hexan-1-ol

Czech Academy of Sciences Publication Activity Database

Štejfa, V.; Fulem, Michal; Růžička, K.; Matějka, P.

2015-01-01

Roč. 402, Sep (2015), 18-29 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : alcohols * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization enthalpy Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015

Determination of the solid-liquid-vapor triple point pressure of carbon

International Nuclear Information System (INIS)

Haaland, D.M.

1976-01-01

A detailed experimental study of the triple point pressure of carbon using laser heating techniques has been completed. Uncertainties and conflict in previous investigations have been addressed and substantial data presented which places the solid-liquid-vapor carbon triple point at 107 +- 2 atmospheres. This is in agreement with most investigations which have located the triple point pressure between 100 and 120 atmospheres, but is in disagreement with recent low pressure carbon experiments. The absence of any significant polymorphs of carbon other than graphite suggests that the graphite-liquid-vapor triple point has been measured. Graphite samples were melted in a pressure vessel using a 400 W Nd:YAG continuous-wave laser focused to a maximum power density of approximately 80 kW/cm 2 . Melt was confirmed by detailed microstructure analysis and x-ray diffraction of the recrystallized graphite. Experiments to determine the minimum melt pressure of carbon were completed as a function of sample size, type of inert gas, and laser power density to asure that laser power densities were sufficient to produce melt at the triple point pressure of carbon, and the pressure of carbon at the surface of the sample was identical to the measured pressure of the inert gas in the pressure vessel. High-speed color cinematography of the carbon heating revealed the presence of a laser-generated vapor or particle plume in front of the sample. The existence of this bright plume pevented the measurement of the carbon triple point temperature

Vapour pressure and enthalpy of vaporization of aliphatic poly-amines

International Nuclear Information System (INIS)

Efimova, Anastasia A.; Emel'yanenko, Vladimir N.; Verevkin, Sergey P.; Chernyak, Yury

2010-01-01

Molar enthalpies of vaporization of aliphatic poly-amines: 1,4-dimethylpiperazine [106-58-1], 1-(2-aminoethyl)-piperazine, [140-31-8], 1-(2-aminoethyl)-4-methyl-piperazine [934-98-5], and triethylenetetramine [112-24-3] were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. A large number of the primary experimental results on temperature dependences of vapour pressures of the parent compounds have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies of poly-amines at the reference temperature 298.15 K. An internal consistency check was performed on enthalpy of vaporization values for poly-amines studied in this work.

Quantitative liquid and vapor distribution measurements in evaporating fuel sprays using laser-induced exciplex fluorescence

International Nuclear Information System (INIS)

Fansler, Todd D; Drake, Michael C; Gajdeczko, Boguslaw; Düwel, Isabell; Koban, Wieland; Zimmermann, Frank P; Schulz, Christof

2009-01-01

Fully quantitative two-dimensional measurements of liquid- and vapor-phase fuel distributions (mass per unit volume) from high-pressure direct-injection gasoline injectors are reported for conditions of both slow and rapid vaporization in a heated, high-pressure spray chamber. The measurements employ the coevaporative gasoline-like fluorobenzene (FB)/diethylmethylamine (DEMA)/hexane exciplex tracer/fuel system. In contrast to most previous laser-induced exciplex-fluorescence (LIEF) experiments, the quantitative results here include regions in which liquid and vapor fuel coexist (e.g. near the injector exit). A unique aspect is evaluation of both vapor- and liquid-phase distributions at varying temperature and pressure using only in situ vapor-phase fluorescence calibration measurements at room temperature and atmospheric pressure. This approach draws on recent extensive measurements of the temperature-dependent spectroscopic properties of the FB–DEMA exciplex system, in particular on knowledge of the quantum efficiencies of the vapor-phase and liquid-phase (exciplex) fluorescence. In addition to procedures necessary for quantitative measurements, we discuss corrections for liquid–vapor crosstalk (liquid fluorescence that overlaps the vapor-fluorescence bandpass), the unknown local temperature due to vaporization-induced cooling, and laser-sheet attenuation by scattering and absorption

Excessively High Vapor Pressure of Al-based Amorphous Alloys

Directory of Open Access Journals (Sweden)

Jae Im Jeong

2015-10-01

Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

Recommended Vapor Pressure of Solid Naphthalen

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Fulem, Michal; Růžička, V.

2005-01-01

Roč. 50, - (2005), s. 1956-1970 ISSN 0021-9568 Institutional research plan: CEZ:AV0Z10100521 Keywords : solid naphthalene * vapor pressure * enthalpy of vaporization * enthalpy of fusion Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.610, year: 2005

Recommended vapor pressures for thiophene, sulfolane, and dimethyl sulfoxide

Czech Academy of Sciences Publication Activity Database

Fulem, Michal; Růžička, K.; Růžička, M.

2011-01-01

Roč. 303, č. 2 (2011), s. 205-216 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z10100521 Keywords : thiophene sulfolane * dimethyl sulfoxide * vapor pressure * heat capacity * vaporization enthalpy * recommended vapor pressure equation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.139, year: 2011

Recommended vapor pressure and thermophysical data for ferrocene

Czech Academy of Sciences Publication Activity Database

Fulem, Michal; Růžička, K.; Červinka, C.; Rocha, M.A.A.; Santos, L.M.N.B.F.; Berg, R.F.

2013-01-01

Roč. 57, FEB (2013), 530-540 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : ferrocene * vapor pressure * heat capacity * ideal gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure equation Subject RIV: BJ - Thermodynamics Impact factor: 2.423, year: 2013

Gasoline Reid Vapor Pressure

Science.gov (United States)

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

Vapour pressures and enthalpies of vaporization of a series of the ferrocene derivatives

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Verevkin, Sergey P.; Krol, Olesya V.; Varushchenko, Raisa M.; Chelovskaya, Nelly V.

2007-01-01

Vapour pressures of the ferrocene, ferrocene-methanol, benzyl-ferrocene, and benzoyl-ferrocene have been determined by the transpiration method. The molar enthalpies of sublimation Δ cr g H m and of vaporization Δ l g H m have been determined from the temperature dependence of the vapour pressure. The molar enthalpies of fusion of these compounds were measured by d.s.c. The measured data sets of vaporization, sublimation, and fusion enthalpies were checked for internal consistency

Thermodynamic functions and vapor pressures of uranium and plutonium oxides at high temperatures

International Nuclear Information System (INIS)

Green, D.W.; Reedy, G.T.; Leibowitz, L.

1977-01-01

The total energy release in a hypothetical reactor accident is sensitive to the total vapor pressure of the fuel. Thermodynamic functions which are accurate at high temperature can be calculated with the methods of statistical mechanics provided that needed spectroscopic data are available. This method of obtaining high-temperature vapor pressures should be greatly superior to the extrapolation of experimental vapor pressure measurements beyond the temperature range studied. Spectroscopic data needed for these calculations are obtained from infrared spectroscopy of matrix-isolated uranium and plutonium oxides. These data allow the assignments of the observed spectra to specific molecular species as well as the calculation of anharmonicities for monoxides, bond angles for dioxides, and molecular geometries for trioxides. These data are then employed, in combination with data on rotational and electronic molecular energy levels, to determine thermodynamic functions that are suitable for the calculation of high-temperature vapor pressures

Some empirical rules concerning the vapor pressure curve revisited

International Nuclear Information System (INIS)

Velasco, S.; White, J.A.

2014-01-01

Highlights: • A Claussius–Claperyron equation is obtained in the Pitzer corresponding states scheme. • Some well-known empirical rules for the vapor pressure are rewritten in terms of the Pitzer acentric factor. • The Guggenheim point follows the corresponding state scheme better than the normal boiling point. • The Ambrose–Walton vapor pressure equation yields excellent agreement with NIST data in all considered cases. -- Abstract: A form for the Clausius–Clapeyron vapor-pressure equation is obtained in the Pitzer corresponding states scheme. This equation allows one to rewrite the well-known Trouton, Guldberg, van Laar and Guggenheim rules in terms of the acentric factor ω. The original forms of these empirical rules are recovered for some particular values of ω. The proposed rules are checked by analyzing National Institute of Standards and Technology (NIST) data on the liquid-vapor coexistence curve for 105 fluids. These rules have been also analyzed by using the well-known Ambrose–Walton (AW) vapor pressure equation

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

International Nuclear Information System (INIS)

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

1982-01-01

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

Vapor Pressures of Several Commercially Used Alkanolamines

NARCIS (Netherlands)

Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine,

Vapor pressure lowering effects due to salinity and suction pressure in the depletion of vapor-dominated geothermal reservoirs

Energy Technology Data Exchange (ETDEWEB)

Battistelli, A. [Aquater S.p.A., Pisa (Italy); Calore, C. [Istituto Internazionale per le Ricerche Geotermiche-CNR, Pisa (Italy); Pruess, K. [Lawrence Berkeley Lab., Berkeley, CA (United States)

1995-03-01

The equation-of-state module able to handle saline brines with non-condensible gas, developed for the TOUGH2 simulator, has been improved to include vapor pressure lowering (VPL) due to suction pressure as represented by Kelvin`s equation. In this equation the effects of salt are considered whereas those of non-condensible gas have currently been neglected. Numerical simulations of fluid production from tight matrix blocks have been performed to evaluate the impact of VPL effects due to salinity and suction pressure on the depletion behaviour of vapor-dominated geothermal reservoirs. Previous studies performed neglected VPL due to suction pressure showed that for initial NaCl mass fractions above threshold values, {open_quotes}sealing{close_quotes} of the block occurs and large amounts of liquid fluid may not be recovered. On the other hand, below the threshold value the matrix block dries out due to fluid production. The inclusion of VPL due to suction pressure does not allow complete vaporization of the liquid phase. As a result, the threshold NaCl concentration above which sealing of the matrix block occurs is increased. Above the {open_quotes}critical{close_quotes} NaCl concentration, block depletion behaviour with and without the VPL due to suction pressure is almost identical, as liquid phase saturation remains high even after long production times. As the VPL due to suction pressure depends mainly on capillary pressure, the shape of capillary pressure functions used in numerical simulations is important in determining VPL effects on block depletion.

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

Science.gov (United States)

Levinson, Gerald S.

1982-01-01

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

The Yaws handbook of vapor pressure Antoine coefficients

CERN Document Server

Yaws, Carl L

2015-01-01

Increased to include over 25,000 organic and inorganic compounds, The Yaws Handbook of Vapor Pressure: Antoine Coefficients, 2nd Edition delivers the most comprehensive and practical database source for today's petrochemical. Understanding antoine coefficients for vapor pressure leads to numerous critical engineering applications such as pure components in storage vessels, pressure relief valve design, flammability limits at the refinery, as well as environmental emissions from exposed liquids, making data to efficiently calculate these daily challenges a fundamental need. Written by the world's leading authority on chemical and petrochemical data, The Yaws Handbook of Vapor Pressure simplifies the guesswork for the engineer and reinforces the credibility of the engineer's calculations with a single trust-worthy source. This data book is a must-have for the engineer's library bookshelf. Increase compound coverage from 8,200 to over 25,000 organic and inorganic compounds, including sulfur and hydrocarbons Sol...

Vapor pressure of plutonium carbide adsorbed on graphite

International Nuclear Information System (INIS)

Tallent, O.K.; Wichner, R.P.; Towns, R.L.; Godsey, T.T.

1984-09-01

An investigation was conducted to obtain data needed to make realistic estimates of plutonium contamination in the primary coolant system in High Temperature Gas-Cooled Reactors (HTGRs). The vapor pressure of plutonium over plutonium sesquicarbide (Pu 2 C 3 ) adsorbed on the surface of H-451 graphite was found to be defined by adsorption isotherms at test temperatures of 1000, 1200, and 1400 0 C. The vapor pressures at low concentrations of Pu 2 C 3 on the surface of the graphite were up to three orders of magnitude below that of pure Pu 2 C 3 at a given temperature. The heat of adsorption increases with decreasing Pu 2 C 3 surface coverage with the measured value at 0.05 μmol Pu 2 C 3 /m 2 being 107.9 kcal/mol. The Pu 2 C 3 concentration required for monolayer surface coverage on the graphite was found to be 3.27 μmol/m 2

High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

Energy Technology Data Exchange (ETDEWEB)

Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail: fgarcias@imp.mx; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)

2007-06-15

In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

International Nuclear Information System (INIS)

Garcia-Sanchez, Fernando; Eliosa-Jimenez, Gaudencio; Silva-Oliver, Guadalupe; Godinez-Silva, Armando

2007-01-01

In this work, new (vapor + liquid) equilibrium data for the (N 2 + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N 2 + n-heptane) system

The effect of deuterium substitution on the vapor pressure of acetonitrile

International Nuclear Information System (INIS)

Jancso, G.; Jakli, Gy.; Koritsanszky, T.

1980-01-01

The vapor pressure difference between CH 3 CN and CD 3 CN was measured by differential capacitance manometry between -40 and +80 deg C. The vapor pressure isotope effects (VPIE) derived from the results may be expressed by the equation: ln(psub(H)/Psub(D))=871.761/T 2 -13.577/T+0.006874. The experimental data were interpreted within the framework of the statistical theory of isotope effects in condensed systems. The largest contribution to the VPIE arises from the shifts in the CH stretching vibrations resulting from condensation which were found to be temperature dependent in good agreement with the available spectroscopic information. (author)

A technique to depress desflurane vapor pressure.

Science.gov (United States)

Brosnan, Robert J; Pypendop, Bruno H

2006-09-01

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

Vapor pressures and enthalpies of vaporization of a series of the linear aliphatic aldehydes

Czech Academy of Sciences Publication Activity Database

Verevkin, S. P.; Krasnykh, E. L.; Vasiltsova, T. V.; Koutek, Bohumír; Doubský, Jan; Heintz, A.

2003-01-01

Roč. 206, - (2003), s. 331-339 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z4055905 Keywords : aldehydes * vapor pressure * enthalpy of vaporization Subject RIV: CC - Organic Chemistry Impact factor: 1.165, year: 2003

The effect of halogen hetero-atoms on the vapor pressures and thermodynamics of polycyclic aromatic compounds measured via the Knudsen effusion technique

International Nuclear Information System (INIS)

Goldfarb, Jillian L.; Suuberg, Eric M.

2008-01-01

Knowledge of vapor pressures of high molar mass organics is essential to predicting their behavior in combustion systems as well as their fate and transport within the environment. This study involved polycyclic aromatic compounds (PACs) containing halogen hetero-atoms, including bromine and chlorine. The vapor pressures of eight PACs, ranging in molar mass from (212 to 336) g . mol -1 , were measured using the isothermal Knudsen effusion technique over the temperature range of (296 to 408) K. These compounds included those with few or no data available in the literature, namely: 1,4-dibromonaphthalene, 5-bromoacenaphthene, 9-bromoanthracene, 1,5-dibromoanthracene, 9,10-dibromoanthracene, 2-chloroanthracene, 9,10-dichloroanthracene, and 1-bromopyrene. Enthalpies of sublimation of these compounds were determined via application of the Clausius-Clapeyron equation. An analysis is presented on the effects of the addition of halogen hetero-atoms to pure polycyclic aromatic hydrocarbons using these data as well as available literature data. As expected, the addition of halogens onto these PACs increases their enthalpies of sublimation and decreases their vapor pressures as compared to the parent compounds

Vapor pressures and thermophysical properties of selected monoterpenoids

Czech Academy of Sciences Publication Activity Database

Štejfa, V.; Dergal, F.; Mokbel, I.; Fulem, Michal; Jose, J.; Růžička, K.

2015-01-01

Roč. 406, Nov (2015), 124-133 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : monoterpenoids * vapor pressure * heat capacity * ideal - gas thermodynamic properties * vaporization and sublimation enthalpy Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015

A gas thermometer for vapor pressure measurements

Science.gov (United States)

Rusin, A. D.

2008-08-01

The pressure of an inert gas over the range 400 1000 K was measured on a tensimetric unit with a quartz membrane pressure gauge of enhanced sensitivity. It was shown that a reactor with a membrane null gauge could be used as a gas thermometer. The experimental confidence pressure and temperature intervals were 0.07 torr and 0.1 K at a significance level of 0.05. A Pt-Pt/10% Rh thermocouple was calibrated; the results were approximated by a polynomial of degree five. The error in temperature calculations was 0.25 K.

Determination of vapor pressures, enthalpies of sublimation, and enthalpies of fusion of benzenetriols

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Schick, Christoph

2004-01-01

Molar enthalpies of sublimation of 1,2,4-, 1,2,3-, and 1,3,5-tri-hydroxy-benzene, were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The molar enthalpies of fusion and molar heat capacities of these compounds were measured by DSC. The measured data sets of vaporization, sublimation and fusion enthalpies were checked for internal consistency. Strength of the inter- and intra-molecular hydrogen bonding in di- and tri-hydroxy-benzenes have been assessed

Vapor pressure data for fatty acids obtained using an adaptation of the DSC technique

International Nuclear Information System (INIS)

Matricarde Falleiro, Rafael M.; Akisawa Silva, Luciana Y.; Meirelles, Antonio J.A.; Krähenbühl, Maria A.

2012-01-01

Highlights: ► Vapor pressure data of fatty acids were measured by Differential Scanning Calorimetry. ► The DSC technique is especially advantageous for expensive chemicals. ► High heating rate was used for measuring the vapor pressure data. ► Antoine constants were obtained for the selected fatty acids. - Abstract: The vapor pressure data for lauric (C 12:0 ), myristic (C 14:0 ), palmitic (C 16:0 ), stearic (C 18:0 ) and oleic (C 18:1 ) acids were obtained using Differential Scanning Calorimetry (DSC). The adjustments made in the experimental procedure included the use of a small sphere (tungsten carbide) placed over the pinhole of the crucible (diameter of 0.8 mm), making it possible to use a faster heating rate than that of the standard method and reducing the experimental time. The measurements were made in the pressure range from 1333 to 9333 Pa, using small sample quantities of fatty acids (3–5 mg) at a heating rate of 25 K min −1 . The results showed the effectiveness of the technique under study, as evidenced by the low temperature deviations in relation to the data reported in the literature. The Antoine constants were fitted to the experimental data whose values are shown in Table 5.

Tropical stratospheric water vapor measured by the microwave limb sounder (MLS)

Science.gov (United States)

Carr, E. S.; Harwood, R. S.; Mote, P. W.; Peckham, G. E.; Suttie, R. A.; Lahoz, W. A.; O'Neill, A.; Froidevaux, L.; Jarnot, R. F.; Read, W. G.

1995-01-01

The lower stratospheric variability of equatorial water vapor, measured by the Microwave Limb Sounder (MLS), follows an annual cycle modulated by the quasi-biennial oscillation. At levels higher in the stratosphere, water vapor measurements exhibit a semi-annual oscillatory signal with the largest amplitudes at 2.2 and 1hPa. Zonal-mean cross sections of MLS water vapor are consistent with previous satellite measurements from the limb infrared monitor of the stratosphere (LIMS) and the stratospheric Aerosol and Gas Experiment 2 (SAGE 2) instruments in that they show water vapor increasing upwards and the polewards from a well defined minimum in the tropics. The minimum values vary in height between the retrieved 46 and 22hPa pressure levels.

Measurement of droplet vaporization rate enhancement caused by acoustic disturbances

Science.gov (United States)

Anderson, T. J.; Winter, M.

1992-10-01

Advanced laser diagnostics are being applied to quantify droplet vaporization enhancement in the presence of acoustic fields which can lead to instability in liquid-fueled rockets. While models have been developed to describe the interactions between subcritical droplet vaporization and acoustic fields in the surrounding gases, they have not been verified experimentally. In the super critical environment of a rocket engine combustor, little is understood about how the injected fluid is distributed. Experiments in these areas have been limited because of the lack of diagnostic techniques capable of providing quantitative results. Recently, however, extremely accurate vaporization rate measurements have been performed on droplets in a subcritical environment using morphology-dependent resonances (MDR's) in which fluorescence from an individual droplet provides information about its diameter. Initial measurements on methanol droplets behind a pressure pulse with a pressure ratio of 1.2 indicated that the evaporation rate in the first few microsec after wave passage was extremely high. Subsequent measurements have been made to validate these results using MDR's acquired from similarly-sized droplets using a pulse with a 1.1 pressure ratio. A baseline measurement was also made using a non evaporative fluid under similar Weber and Reynolds number conditions. The MDR technique employed for these measurements is explained and the facilities are described. The evaporation measurement results are shown and the rates observed from different droplet materials and different wave strengths are compared.

Vapor pressure and vapor fractionation of silicate melts of tektite composition

Science.gov (United States)

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

1964-01-01

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

PWFA plasma source - interferometric diagnostics for Li vapor density measurements

International Nuclear Information System (INIS)

Sivakumaran, V.; Mohandas, K.K.; Singh, Sneha; Ravi Kumar, A.V.

2015-01-01

A prototype (40 cm long) plasma source based on Li heat pipe oven has been developed for the Plasma Wakefield Acceleration (PWFA) experiments at IPR (IPR), Gujarat as a part of the ongoing Accelerator Programme. Li vapor in the oven is produced by heating solid Li in helium buffer gas. A uniform column of Li plasma is generated by UV photo ionization (193 nm) of the Li vapor in the heat pipe oven. In these experiments, an accurate measurement of Li vapor density is important as it has got a direct consequence on the plasma electron density. In the present experiment, the vapor density is measured optically by using Hook method (spectrally resolved white light interferometry). The hook like structure formed near the vicinity of the Li 670.8 nm resonance line was recorded with a white light Mach Zehnder interferometer crossed with an imaging spectrograph to estimate the Li vapor density. The vapor density measurements have been carried out as a function of external oven temperature and the He buffer gas pressure. This technique has the advantage of being insensitive to line broadening and line shape, and its high dynamic range even with optically thick absorption line. Here, we present the line integrated Lithium vapor density measurement using Hook method and also compare the same with other optical diagnostic techniques (White light absorption and UV absorption) for Li vapor density measurements. (author)

Thermodynamic consistency of vapor pressure and calorimetric data for argon, krypton, and xenon

International Nuclear Information System (INIS)

Schwalbe, L.A.; Crawford, R.K.; Chen, H.H.; Aziz, R.A.

1977-01-01

A new two-parameter vapor pressure equation has been derived which, unlike the Salter equation, is shown to be equally applicable to quantum or classical solids and even liquids. The condensed phase enthalpies and entropies are given directly by the fitted parameters with accuracies comparable to those which have been claimed for existing independent calorimetric measurements. Recent vapor pressure data for the solid and liquid phases of argon, krypton, and xenon are analyzed in this manner, and the results are compared with the available calorimetric data. New values for the cohesive energy at T=0 are also derived for these substances

Vapor pressures and enthalpies of vaporization of a series of γ and δ-lactones by correlation gas chromatography

International Nuclear Information System (INIS)

Kozlovskiy, Mikhail; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpies of γ-octanolactone, γ- and δ-undecanolactone and γ and δ-dodecanolactone are reported. • Equations for predicting the vapor pressures over the temperature range T = (298.15 to 350) K are provided. • Vaporization enthalpies are compared to predicted values. - Abstract: The vaporization enthalpies of γ-octanolactone, γ- and δ-undecanolactone and γ and δ-dodecanolactone used commercially as flavor ingredients are reported as are their vapor pressures over the temperature range T = (298.15 to 350) K. Vaporization enthalpies at T = 298.15 K of: (66.0 ± 3.9), (79.4 ± 4.4), (80.1 ± 4.5), (83.9 ± 4.6), and (84.61 ± 4.7) kJ · mol −1 and vapor pressures also at T = 298.15 K of: (2.8 ± 0.9), (0.12 ± 0.05), (0.09 ± 0.04), (0.04 ± 0.02), and (0.03 ± 0.02) Pa, respectively, have been evaluated by correlation gas chromatography experiments. The vaporization enthalpies of the lactones studied are reproduced within ±0.5 kJ · mol −1 using a group additivity scheme reported previously for γ- and δ-lactones. The vaporization enthalpies of the γ- and δ-lactones are compared to a similar series of ω-lactones

The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, vapor pressure measurements, and ab initio calculations.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas

2007-04-04

Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of vapor pressure, enthalpy of vaporization, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of vaporization of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the vapor pressure measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.

Vapor pressure data for fatty acids obtained using an adaptation of the DSC technique

Energy Technology Data Exchange (ETDEWEB)

Matricarde Falleiro, Rafael M. [LPT, Departamento de Processos Quimicos (DPQ), Faculdade de Engenharia Quimica, Universidade de Campinas (UNICAMP), 13083-852 Campinas - SP (Brazil); Akisawa Silva, Luciana Y. [Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo (UNIFESP), 09972-270 Diadema - SP (Brazil); Meirelles, Antonio J.A. [EXTRAE, Departamento de Engenharia de Alimentos (DEA), Faculdade de Engenharia de Alimentos, Universidade de Campinas (UNICAMP), 13083-862 Campinas - SP (Brazil); Kraehenbuehl, Maria A., E-mail: mak@feq.unicamp.br [LPT, Departamento de Processos Quimicos (DPQ), Faculdade de Engenharia Quimica, Universidade de Campinas (UNICAMP), 13083-852 Campinas - SP (Brazil)

2012-11-10

Highlights: Black-Right-Pointing-Pointer Vapor pressure data of fatty acids were measured by Differential Scanning Calorimetry. Black-Right-Pointing-Pointer The DSC technique is especially advantageous for expensive chemicals. Black-Right-Pointing-Pointer High heating rate was used for measuring the vapor pressure data. Black-Right-Pointing-Pointer Antoine constants were obtained for the selected fatty acids. - Abstract: The vapor pressure data for lauric (C{sub 12:0}), myristic (C{sub 14:0}), palmitic (C{sub 16:0}), stearic (C{sub 18:0}) and oleic (C{sub 18:1}) acids were obtained using Differential Scanning Calorimetry (DSC). The adjustments made in the experimental procedure included the use of a small sphere (tungsten carbide) placed over the pinhole of the crucible (diameter of 0.8 mm), making it possible to use a faster heating rate than that of the standard method and reducing the experimental time. The measurements were made in the pressure range from 1333 to 9333 Pa, using small sample quantities of fatty acids (3-5 mg) at a heating rate of 25 K min{sup -1}. The results showed the effectiveness of the technique under study, as evidenced by the low temperature deviations in relation to the data reported in the literature. The Antoine constants were fitted to the experimental data whose values are shown in Table 5.

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

Science.gov (United States)

MacLeod, Matthew; Scheringer, Martin; Hungerbühler, Konrad

2007-04-15

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

Supplementary vapor pressure data of the glycol ethers, 1-methoxy-2-propanol, and 2-methoxyethanol at a pressure range of (15 to 177) kPa

International Nuclear Information System (INIS)

Bejarano, Arturo; Poveda, Laura J.; Fuente, Juan C. de la

2012-01-01

Highlights: ► Vapor pressure of 2-methoxyethanol and 1-methoxy-2-propanol were measured. ► Complementary data are reported at ranges of (342 to 417) K and (15 to 177) kPa. ► Three commonly used vapor pressure equations were fitted to experimental data. ► The parameters of Antoine and Wagner type equations were estimated. ► The relative deviations (rmsd) from the three vapor pressure equations were <0.4%. - Abstract: The vapor pressure of pure 1-methoxy-2-propanol and 2-methoxyethanol, commonly used as co-solvents in inks, paints, coatings, organic/water solutions among many other applications, were measured with a dynamic recirculation apparatus at a pressure range of (15 to 177) kPa. The measurements were performed at temperature ranges of (342 to 412) K for 1-methoxy-2-propanol and (346 to 417) K for 2-methoxyethanol. The maximum likelihood method was used to estimate the parameters of the Antoine equation, the parameters of an extended Antoine equation and the Wagner equation were determined by non linear least squares method. The three models showed root mean square deviations (rmsd) of 0.39%, 0.38%, and 0.29%, and 0.37%, 0.33%, and 0.32%, for 1-methoxy-2-propanol and 2-methoxyethanol, respectively. Additionally, the experimental data and correlation were compared with those available in the literature.

Distribution of Vapor Pressure in the Vacuum Freeze-Drying Equipment

Directory of Open Access Journals (Sweden)

Shiwei Zhang

2012-01-01

Full Text Available In the big vacuum freeze-drying equipment, the drying rate of materials is uneven at different positions. This phenomenon can be explained by the uneven distribution of vapor pressure in chamber during the freeze-drying process. In this paper, a mathematical model is developed to describe the vapor flow in the passageways either between material plates and in the channel between plate groups. The distribution of vapor pressure along flow passageway is given. Two characteristic factors of passageways are defined to express the effects of structural and process parameters on vapor pressure distribution. The affecting factors and their actions are quantitatively discussed in detail. Two examples are calculated and analyzed. The analysis method and the conclusions are useful to estimate the difference of material drying rate at different parts in equipment and to direct the choice of structural and process parameters.

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

Science.gov (United States)

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

2012-07-01

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

Water-vapor pressure control in a volume

Science.gov (United States)

Scialdone, J. J.

1978-01-01

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

Evaporation monitoring and composition control of alloy systems with widely differing vapor pressures

International Nuclear Information System (INIS)

Anklam, T.M.; Berzins, L.V.; Braun, D.G.; Haynam, C.; McClelland, M.A.; Meier, T.

1994-10-01

Lawrence Livermore National Laboratory is developing sensors and controls to improve and extend electron beam materials processing technology to alloy systems with constituents of widely varying vapor pressure. The approach under development involves using tunable lasers to measure the density and composition of the vapor plume. A laser based vaporizer control system for vaporization of a uranium-iron alloy has been previously demonstrated in multi-hundred hour, high rate vaporization experiments at LLNL. This paper reviews the design and performance of the uranium vaporization sensor and control system and discusses the extension of the technology to monitoring of uranium vaporization. Data is presented from an experiment in which titanium wire was fed into a molten niobium pool. Laser data is compared to deposited film composition and film cross sections. Finally, the potential for using this technique for composition control in melting applications is discussed

Communication: Dynamical and structural analyses of solid hydrogen under vapor pressure

Energy Technology Data Exchange (ETDEWEB)

Hyeon-Deuk, Kim, E-mail: kim@kuchem.kyoto-u.ac.jp [Department of Chemistry, Kyoto University, Kyoto 606-8502 (Japan); Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ando, Koji [Department of Chemistry, Kyoto University, Kyoto 606-8502 (Japan)

2015-11-07

Nuclear quantum effects play a dominant role in determining the phase diagram of H{sub 2}. With a recently developed quantum molecular dynamics simulation method, we examine dynamical and structural characters of solid H{sub 2} under vapor pressure, demonstrating the difference from liquid and high-pressure solid H{sub 2}. While stable hexagonal close-packed lattice structures are reproduced with reasonable lattice phonon frequencies, the most stable adjacent configuration exhibits a zigzag structure, in contrast with the T-shape liquid configuration. The periodic angular distributions of H{sub 2} molecules indicate that molecules are not a completely free rotor in the vapor-pressure solid reflecting asymmetric potentials from surrounding molecules on adjacent lattice sites. Discrete jumps of librational and H–H vibrational frequencies as well as H–H bond length caused by structural rearrangements under vapor pressure effectively discriminate the liquid and solid phases. The obtained dynamical and structural information of the vapor-pressure H{sub 2} solid will be useful in monitoring thermodynamic states of condensed hydrogens.

Ammonia IR Absorbance Measurements with an Equilibrium Vapor Cell

National Research Council Canada - National Science Library

Field, Paul

2004-01-01

Infrared (IR) absorbance spectra were acquired for 18 ammonia vapor pressures. The vapor pressures were generated with 15 gravimetrically prepared aqueous solutions and three commercial aqueous solutions using a dynamic method I.E...

Characteristics of the Na/beta-alumina/Na cell as a sodium vapor pressure sensor

International Nuclear Information System (INIS)

Takikawa, O.; Imai, A.; Harata, M.

1982-01-01

The EMF and voltage-current characteristics for a galvanic cell with the configuration Na vapor (P 1 )/sodium beta-alumina/Na vapor (P 2 ) were studied. It was verified that the EMF followed the Nernst relation over a wide pressure range. For example, when P 1 = 2 x 10 -2 mm Hg and beta-alumina temperature = 340 0 C, the measured EMF agreed with the calculated value in P 2 range from 10 -5 to 10 -2 mm Hg. At lower pressure range, the measured EMF showed a negative deviation. Coexisting argon gas did not influence the cell EMF characteristic. In an atmosphere containing oxygen, the measured EMF was very high at first. Then it decreased and finally approached a value which agreed with the Nernst equation after several hours. At low beta-alumina temperatures, current saturation was observed in the voltage versus current relation with the anode on the P 2 side. Although the sodium pressure could be determined from saturating current measurement, the measurable pressure range was narrower than that for EMF measurement. At high beta-alumina temperature, current saturation was not clear. Values of 6 x 10 -6 (Ω cm) -1 for the electron conductivity and 6 x 10 -10 (Ω cm) -1 for the hole conductivity at 340 0 C were obtained for beta-alumina from the voltage-current characteristics at low sodium pressure. (Auth.)

The Oxidation Rate of SiC in High Pressure Water Vapor Environments

Science.gov (United States)

Opila, Elizabeth J.; Robinson, R. Craig

1999-01-01

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

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

Science.gov (United States)

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

2007-09-07

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

Achieving uniform layer deposition by atmospheric-pressure plasma-enhanced chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae-Ok [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Kang, Woo Seok, E-mail: kang@kimm.re.kr [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Department of Environment & Energy Mechanical Engineering, University of Science & Technology (UST), Daejeon 305-350 (Korea, Republic of); Hur, Min; Lee, Jin Young [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Song, Young-Hoon [Department of Plasma Engineering, Korea Institute of Machinery & Materials (KIMM), Daejeon 305-343 (Korea, Republic of); Department of Environment & Energy Mechanical Engineering, University of Science & Technology (UST), Daejeon 305-350 (Korea, Republic of)

2015-12-31

This work investigates the use of plasma-enhanced chemical vapor deposition under atmospheric pressure for achieving uniform layer formation. Electrical and optical measurements demonstrated that the counterbalance between oxygen and precursors maintained the homogeneous discharge mode, while creating intermediate species for layer deposition. Several steps of the deposition process of the layers, which were processed on a stationary stage, were affected by flow stream and precursor depletion. This study showed that by changing the flow streamlines using substrate stage motion uniform layer deposition under atmospheric pressure can be achieved. - Highlights: • Zirconium oxide was deposited by atmospheric-pressure plasma-enhanced chemical vapor deposition. • Homogeneous plasma was maintained by counterbalancing between discharge gas and precursors. • Several deposition steps were observed affected by the gas flow stream and precursor depletion. • Thin film layer was uniformly grown when the substrate underwent a sweeping motion.

High temperature vapor pressures of stainless steel type 1.4970 and of some other pure metals from laser evaporation

International Nuclear Information System (INIS)

Bober, M.; Singer, J.

1984-10-01

For the safety analysis of nuclear reactors vapor pressure data of stainless steel are required up to temperatures exceeding 4000 K. In analogy to the classic boiling point method a new technique was developed to measure the high-temperature vapor pressures of stainless steel and other metals from laser vaporization. A fast pyrometer, an ion current probe and an image converter camera are used to detect incipient boiling from the time-temperature curve. The saturated-vapor pressure curves of stainless steel (Type 1.4970), being a cladding material of the SNR 300 breeder reactor, and of molybdenum are experimentally determined in the temperature ranges of 2800-3900 K and 4500-5200 K, respectively. The normal boiling points of iron, nickel, titanium, vanadium and zirconium are verified. Besides, spectral emissivity values of the liquid metals are measured at the pyrometer wavelengths of 752 nm and/or 940 nm. (orig.) [de

The vapor pressure and vaporization enthalpy of R-(+)-menthofuran, a hepatotoxin metabolically derived from the abortifacient terpene, (R)-(+)-pulegone by correlation gas chromatography

International Nuclear Information System (INIS)

Gobble, Chase; Chickos, James S.

2016-01-01

Highlights: • The vaporization enthalpy and vapor pressure of R-(+) menthofuran is evaluated. • The normal boiling temperature is predicted and compared to experimental and predicted values. • A vapor pressure equation as a function of temperature for menthofuran is evaluated. - Abstract: The vapor pressure as a function of temperature and its vaporization enthalpy at T = 298.15 K of R-(+)-menthofuran, a substance metabolically derived from R-(+)-pulegone that is both a flavoring agent at low concentrations and a hepatotoxin at larger ones, is evaluated by correlation-gas chromatography. A vapor pressure p/Pa = (36 ± 12) has been evaluated at T = 298.15 K, and a normal boiling temperature of T_b/K = 482.4 K is predicted. A boiling temperature of T_b/K = 374.3 compares with the literature value of T_b/K = 371.2 at reduced pressure, p/kPa = 2.93. The vaporization enthalpy of (56.5 ± 3.0) kJ·mol"−"1 compares to an estimated value of (57.8 ± 2.9) kJ·mol"−"1.

Vapor pressure data for ethyl-2-methylbutyrate, hexanal and (E)-2-hexenal at a pressure range of (25 to 190) kPa

International Nuclear Information System (INIS)

Meneses, David A.; Bejarano, Arturo; Fuente, Juan C. de la

2014-01-01

Highlights: • Vapor pressures of three pure apple aroma constituents were measured. • Measurements were made over the temperature range of (362.1 to 429.9) K. • Constants of Antoine and Wagner type equations were fitted to the experimental data. • Relative deviations (rmsd) from the three vapor-pressure equations were <0.9%. • Contrast with literature showed discrepancies <9% among them and with this work. - Abstract: The saturated vapor pressures of pure ethyl-2-methylbutyrate, hexanal and (E)-2-hexenal, which are volatile compounds characteristic of apple aroma, were measured with a dynamic recirculation apparatus at a pressure range of (24.5 to 190.0) kPa. Measurements were made over the temperature range of (362.1 to 429.9) K for ethyl-2-methylbutyrate, (358.1 to 425.8) K for hexanal, and (373.5 to 446.2) K for (E)-2-hexenal. The maximum likelihood method was used to estimate the parameters of the Antoine equation, whereas the parameters of an extended Antoine equation and the Wagner equation were determined by non linear least square method. The three models showed root mean square deviations (rmsd) of 0.29%, 0.28%, and 0.27% for ethyl-2-methylbutyrate, 0.58%, 0.48%, and 0.38% for hexanal, and 0.89%, 0.62% and 0.36% for (E)-2-hexenal, respectively. Additionally, the experimental data and correlation were compared with those available in the literature

Vapor pressure of selected organic iodides

Czech Academy of Sciences Publication Activity Database

Fulem, M.; Růžička, K.; Morávek, P.; Pangrác, Jiří; Hulicius, Eduard; Kozyrkin, B.; Shatunov, V.

2010-01-01

Roč. 55, č. 11 (2010), 4780-4784 ISSN 0021-9568 R&D Projects: GA ČR GA203/08/0217 Institutional research plan: CEZ:AV0Z10100521 Keywords : vapor pressure * static method * organic iodides Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.089, year : 2010

Prediction of vapor pressure and heats of vaporization of edible oil/fat compounds by group contribution

DEFF Research Database (Denmark)

Ceriani, Roberta; Gani, Rafiqul; Liu, Y.A.

2013-01-01

In the present work, a group contribution method is proposed for the estimation of vapor pressures and heats of vaporization of organic liquids found in edible fat/oil and biofuel industries as a function of temperature. The regression of group contribution parameters was based on an extensive...

Saturated vapor pressure of lutetium tris-acetylacetonate

Energy Technology Data Exchange (ETDEWEB)

Trembovetskij, G.V.; Berdonosov, S.S.; Murav' eva, I.A.; Martynenko, L.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

1983-12-01

By the statical method using /sup 177/Lu radioactive isotope the saturated vapor pressure of anhydrous lutetium acetylacetonate at 130 to 160 deg is determined. The calculations are carried out assuming the vapor to be monomolecular. The equation of lgP versus 1/T takes the form: lg Psub((mmHg))=(8.7+-1.6)-(4110+-690)/T. The thermodynamical characteristics of LuA/sub 3/ sublimation are calculated to be ..delta..Hsub(subl.)=79+-13 kJ/mol; ..delta..Ssub(subl.)=111+-20 J/kxmol.

Complementary vapor pressure data for 2-methyl-1-propanol and 3-methyl-1-butanol at a pressure range of (15 to 177) kPa

Energy Technology Data Exchange (ETDEWEB)

Bejarano, Arturo; Quezada, Nathalie [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile); Fuente, Juan C. de la [Departamento de Ingenieria Quimica y Ambiental, Universidad Tecnica Federico Santa Maria, Avda. Espana 1680, Valparaiso (Chile)], E-mail: juan.delafuente@usm.cl

2009-09-15

The vapor pressure of pure 2-methyl-1-propanol and 3-methyl-1-butanol, components called congeners that are present in aroma of wine, pisco, and other alcoholic beverages, were measured with a dynamic recirculation apparatus at a pressure range of (15 to 177) kPa with an estimated uncertainty <0.2%. The measurements were performed at temperature ranges of (337 to 392) K for 2-methyl-1-propanol and (358 to 422) K for 3-methyl-1-butanol. Data were correlated using a Wagner-type equation with standard deviations of 0.09 kPa for the vapor pressure of 2-methyl-1-propanol and 0.21 kPa for 3-methyl-1-butanol. The experimental data and correlation were compared with data selected from the literature.

Water vapor spectroscopy in the 815-nm wavelength region for Differential Absorption Lidar measurements

Science.gov (United States)

Ponsardin, Patrick; Browell, Edward V.

1995-01-01

The differential absorption lidar (DIAL) technique was first applied to the remote measurement of atmospheric water vapor profiles from airborne platforms in 1981. The successful interpretation of the lidar profiles relies strongly on an accurate knowledge of specific water vapor absorption line parameters: line strength, pressure broadening coefficient, pressure-induced shift coefficient and the respective temperature-dependence factors. NASA Langley Research Center has developed and is currently testing an autonomous airborne water vapor lidar system: LASE (Lidar Atmospheric Sensing Experiment). This DIAL system uses a Nd:YAG-pumped Ti:Sapphire laser seeded by a diode laser as a lidar transmitter. The tunable diode has been selected to operate in the 813-818 nm wavelength region. This 5-nm spectral interval offers a large distribution of strengths for temperature-insensitive water vapor absorption lines. In support of the LASE project, a series of spectroscopic measurements were conducted for the 16 absorption lines that have been identified for use in the LASE measurements. Prior to this work, the experimental data for this water vapor absorption band were limited - to our knowledge - to the line strengths and to the line positions.

Vapor Pressure and Evaporation Coefficient of Silicon Monoxide over a Mixture of Silicon and Silica

Science.gov (United States)

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

2012-01-01

The evaporation coefficient and equilibrium vapor pressure of silicon monoxide over a mixture of silicon and vitreous silica have been studied over the temperature range (1433 to 1608) K. The evaporation coefficient for this temperature range was (0.007 plus or minus 0.002) and is approximately an order of magnitude lower than the evaporation coefficient over amorphous silicon monoxide powder and in general agreement with previous measurements of this quantity. The enthalpy of reaction at 298.15 K for this reaction was calculated via second and third law analyses as (355 plus or minus 25) kJ per mol and (363.6 plus or minus 4.1) kJ per mol respectively. In comparison with previous work with the evaporation of amorphous silicon monoxide powder as well as other experimental measurements of the vapor pressure of silicon monoxide gas over mixtures of silicon and silica, these systems all tend to give similar equilibrium vapor pressures when the evaporation coefficient is correctly taken into account. This provides further evidence that amorphous silicon monoxide is an intimate mixture of small domains of silicon and silica and not strictly a true compound.

Vapor pressures of dimethylcadmium, trimethylbismuth, and tris(dimethylamino)antimony

Czech Academy of Sciences Publication Activity Database

Morávek, Pavel; Fulem, Michal; Pangrác, Jiří; Hulicius, Eduard; Růžička, K.

2013-01-01

Roč. 360, Dec (2013), s. 106-110 ISSN 0378-3812 R&D Projects: GA ČR GA13-15286S; GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : vapor pressure * dimethylcadmium * trimethylbismuth * tris(dimethylamino)antimony * sublimation and vaporization enthalpy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.241, year: 2013

A thermodynamic study of glucose and related oligomers in aqueous solution: Vapor pressures and enthalpies of mixing

DEFF Research Database (Denmark)

Cooke, S.A.; Jonsdottir, Svava Osk; Westh, Peter

2002-01-01

Vapor pressures above aqueous solutions of glucose and maltose at both 298.06 K and 317.99 K and vapor pressures above aqueous solutions of cellobiose, maltotriose, maltotetraose, and maltopentaose at 317.99 K have been measured. The excess enthalpies have been recorded for all of the above-menti...... in aqueous solution. This so-called transference principle is found to be of interest in furthering the discussion concerning the applicability of lattice-based models for solution theory....

Experimental Results For Hydrocarbon Refrigerant Vaporization In Brazed Plate Heat Exchangers at High Pressure

OpenAIRE

Desideri, Adriano; Schmidt Ommen, Torben; Wronski, Jorrit; Quoilin, Sylvain; Lemort, Vincent; Haglind, Fredrik

2016-01-01

In this contribution, the experimental heat transfer coefficient  and the pressure drop measured during HFC refrigerants vaporization inside small brazed plate heat exchanger (PHE) at typical evaporation temperature for organic Rankine cycle systems for low thermal energy quality applications are presented. Scientific work focusing on the heat transfer in PHEs has been carried out since the late 19th century. More recent publications have been focusing on vaporization and condensation of ref...

[Measurement of atomic number of alkali vapor and pressure of buffer gas based on atomic absorption].

Science.gov (United States)

Zheng, Hui-jie; Quan, Wei; Liu, Xiang; Chen, Yao; Lu, Ji-xi

2015-02-01

High sensitivitymagnetic measurementscanbe achieved by utilizing atomic spinmanipulation in the spin-exchange-relaxation-free (SERF) regime, which uses an alkali cell as a sensing element. The atomic number density of the alkali vapor and the pressure of the buffer gasare among the most important parameters of the cell andrequire accurate measurement. A method has been proposed and developedto measure the atomic number density and the pressure based on absorption spectroscopy, by sweeping the absorption line and fittingthe experiment data with a Lorentzian profile to obtainboth parameters. Due to Doppler broadening and pressure broadening, which is mainly dominated by the temperature of the cell and the pressure of buffer gas respectively, this work demonstrates a simulation of the errorbetween the peaks of the Lorentzian profile and the Voigt profile caused by bothfactors. The results indicates that the Doppler broadening contribution is insignificant with an error less than 0.015% at 313-513 K for a 4He density of 2 amg, and an error of 0.1% in the presence of 0.6-5 amg at 393 K. We conclude that the Doppler broadening could be ignored under above conditions, and that the Lorentzianprofile is suitably applied to fit the absorption spectrumobtainingboth parameters simultaneously. In addition we discuss the resolution and the instability due to thelight source, wavelength and the temperature of the cell. We find that the cell temperature, whose uncertainty is two orders of magnitude larger than the instability of the light source and the wavelength, is one of the main factors which contributes to the error.

Controlling Vapor Pressure In Hanging-Drop Crystallization

Science.gov (United States)

Carter, Daniel C.; Smith, Robbie

1988-01-01

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

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

Science.gov (United States)

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

2016-05-01

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

Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

Science.gov (United States)

Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

2008-01-01

Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

Measurement and correlation of (vapor + liquid) equilibrium data for {α-pinene + p-cymene + (S)-(−)-limonene} ternary system at atmospheric pressure

International Nuclear Information System (INIS)

Sun, Lixia; Liao, Dankui; Yang, Zhengyu; Chen, Xiaopeng; Tong, Zhangfa

2013-01-01

Highlights: ► The VLE data of (α-pinene + p-cymene) and (α-pinene + p-cymene + (S)-(−)-limonene) at atmospheric pressure were measured. ► The VLE data of binary system were correlated by four activity coefficient models. ► The ternary VLE data were predicted from binary parameters of the Liebermann–Fried model. ► The constant G 123 E counters plotted on the Roozeboom diagrams. -- Abstract: (Vapor + liquid) equilibrium (VLE) data for binary system of (α-pinene + p-cymene) and ternary system of {α-pinene + p-cymene + (S)-(−)-limonene} were measured at 100.7 kPa using the modified Ellis equilibrium still. The VLE data are thermodynamically consistent. Parameters of the binary system for the four solution models — Liebermann–Fried, Wilson, NRTL, and UNIQUAC — were calculated by referencing least squares method to minimize an objective function based on the total pressure. The ternary system data were predicted with the parameters of Liebermann–Fried model obtained from the pertinent binary systems. The predicted bubble-point temperature and the vapor composition for the ternary system were in good agreement with the experimental results. Smooth representations of the results are used to construct constant excess Gibbs free energy contours on Roozeboom diagrams

On the critical temperature, normal boiling point, and vapor pressure of ionic liquids.

Science.gov (United States)

Rebelo, Luis P N; Canongia Lopes, José N; Esperança, José M S S; Filipe, Eduardo

2005-04-07

One-stage, reduced-pressure distillations at moderate temperature of 1-decyl- and 1-dodecyl-3-methylimidazolium bistriflilamide ([Ntf(2)](-)) ionic liquids (ILs) have been performed. These liquid-vapor equilibria can be understood in light of predictions for normal boiling points of ILs. The predictions are based on experimental surface tension and density data, which are used to estimate the critical points of several ILs and their corresponding normal boiling temperatures. In contrast to the situation found for relatively unstable ILs at high-temperature such as those containing [BF(4)](-) or [PF(6)](-) anions, [Ntf(2)](-)-based ILs constitute a promising class in which reliable, accurate vapor pressure measurements can in principle be performed. This property is paramount for assisting in the development and testing of accurate molecular models.

On Localized Vapor Pressure Gradients Governing Condensation and Frost Phenomena.

Science.gov (United States)

Nath, Saurabh; Boreyko, Jonathan B

2016-08-23

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

Adiabatic pressure dependence of the 2.7 and 1.9 micron water vapor bands

Science.gov (United States)

Mathai, C. V.; Walls, W. L.; Broersma, S.

1977-01-01

An acoustic excitation technique is used to determine the adiabatic pressure derivative of the spectral absorptance of the 2.7 and 1.9 micron water vapor bands, and the 3.5 micron HCl band. The dependence of this derivative on thermodynamic parameters such as temperature, concentration, and pressure is evaluated. A cross-flow water vapor system is used to measure spectral absorptance. Taking F as the ratio of nonrigid to rotor line strengths, it is found that an F factor correction is needed for the 2.7 micron band. The F factor for the 1.9 micron band is also determined. In the wings of each band a wavelength can be found where the concentration dependence is predominant. Farther out in the wings a local maximum occurs for the temperature derivative. It is suggested that the pressure derivative is significant in the core of the band.

Vapor pressure determination of liquid UO/sub 2/ using a boiling point technique

International Nuclear Information System (INIS)

Bober, M.; Singer, J.

1987-01-01

By analogy with the classic boiling point method, a quasi-stationary millisecond laser-heating technique was applied to measure the saturated vapor pressure curve of liquid UO/sub 2/ in the temperature range of 3500 to 4500 K. The results are represented by log rho (MPa)=5.049 - 23 042/T (K), which gives an average heat of vaporization of 441 kJ/mol and a normal boiling point of 3808 K. In addition, spectral emissivities of liquid UO/sub 2/ were determined as a function of the temperature at the pyrometer wavelengths of 752 and 1064 nm

Liquid-vapor phase transition upon pressure decrease in the lead-bismuth system

Science.gov (United States)

Volodin, V. N.

2009-11-01

The liquid-vapor phase transitions boundaries were calculated on the basis of the values of vapor pressure of the components in the lead-bismuth system during the stepwise pressure decrease by one order of magnitude from 105 down to 1 Pa. The emergence of azeotropic liquid under pressure lower than 19.3 kPa was ascertained. The emergence of azeotropic mixture near the lead edge of the phase diagram was concluded to be the reason for technological difficulties in the distillation separation of the system into the components in a vacuum.

Modeling vapor pressures of solvent systems with and without a salt effect: An extension of the LSER approach

International Nuclear Information System (INIS)

Senol, Aynur

2015-01-01

Highlights: • A new polynomial vapor pressure approach for pure solvents is presented. • Solvation models reproduce the vapor pressure data within a 4% mean error. • A concentration-basis vapor pressure model is also implemented on relevant systems. • The reliability of existing models was analyzed using log-ratio objective function. - Abstract: A new polynomial vapor pressure approach for pure solvents is presented. The model is incorporated into the LSER (linear solvation energy relation) based solvation model framework and checked for consistency in reproducing experimental vapor pressures of salt-containing solvent systems. The developed two structural forms of the generalized solvation model (Senol, 2013) provide a relatively accurate description of the salting effect on vapor pressure of (solvent + salt) systems. The equilibrium data spanning vapor pressures of eighteen (solvent + salt) and three (solvent (1) + solvent (2) + salt) systems have been subjected to establish the basis for the model reliability analysis using a log-ratio objective function. The examined vapor pressure relations reproduce the observed performance relatively accurately, yielding the overall design factors of 1.084, 1.091 and 1.052 for the integrated property-basis solvation model (USMIP), reduced property-basis solvation model and concentration-dependent model, respectively. Both the integrated property-basis and reduced property-basis solvation models were able to simulate satisfactorily the vapor pressure data of a binary solvent mixture involving a salt, yielding an overall mean error of 5.2%

Calculation of vapor pressure of fission product fluorides and oxyfluorides

International Nuclear Information System (INIS)

Roux, J.P.

1976-03-01

The equilibrium diagrams of the condensed phases - solid and liquid - and vapor phase are collected for the principal fluorides and oxyfluorides of fission product elements (atomic number from 30 to 66). These diagrams are used more particularly in fuel reprocessing by fluoride volatility process. Calculations and curves (vapor pressure in function of temperature) are processed using a computer program given in this report [fr

Vapor pressure isotope effect in 13CClF3/12CClF3 by cryogenic distillation kinetics

International Nuclear Information System (INIS)

Wieck, H.J.; Ishida, T.

1975-08-01

The vapor pressure of 13 CClF 3 relative to the vapor pressure of 12 CClF 3 was measured as a function of temperature between 169 0 and 206 0 K by using a modified Bigeleisen distillation column. The transient build-up of the isotopic concentration gradient along the length of the packed column during the start-up period was monitored by taking samples from the condenser section as a function of time. The gaseous samples were completely oxidized to carbon dioxide in the presence of a platinum catalyst and a large excess of oxygen at temperatures between 1050 and 1100 0 C. The combustion products were purified by means of gas chromatography, and the purified carbon dioxide samples were analyzed in a Nier-type isotope-ratio mass spectrometer. The data of each distillation run were reduced in the light of Cohen's theory of the kinetics of square cascade of close-separation stages. The vapor pressure isotope effect for the carbon substitution in CClF 3 at temperatures between 169 0 and 206 0 K was found to be an inverse effect and to be rather insensitive to changes in temperature. The relative vapor pressure may be expressed 1n(P'/P) = [(1.5 +- 14.1)/T 2 ] - [(0.159 +- 0.076)/T], or 1n(P'/P) = [(0.173 +- 0.098)/T] - [(0.11 +- 0.53) x 10 -3 ], where P' and P are the vapor pressures of 12 CClF 3 and 13 CClF 3 , respectively. To the first-order, the presence of chlorine isotopes would not affect the fractionation of carbon isotopes by the distillation of CClF 3

Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure%Vapor-Liquid Phase Equilibria for Carbon Dioxide-I- Isopentanol Binary System at Elevated Pressure

Institute of Scientific and Technical Information of China (English)

王琳; 曹丰璞; 刘珊珊; 杨浩

2011-01-01

High-pressure vapor-liquid phase equilibrium data for carbon dioxide＋ isopentanol were measured at tempera- tures of 313.2, 323.1, 333.5 and 343.4 K in the pressure range of 4.64 to 12.71 MPa in a variable-volume high-pressure visual cell. The experimental data were well correlated with Peng-Robinson equation of state （PR-EOS） together with van der Waals-2 two-parameter mixing rule, and the binary interaction parameters were obtained. Henry coefficients and partial molar volumes of CO2 at infinite dilution were estimated based on Krichevsky-Kasarnovsky equation, and Henry coefficients increase with increasing temperature, however, partial molar volumes of CO2 at infinite dilution are negative and the magnitudes decrease with temperature.

Vapor pressures of oxide reactor fuels above 3000 K: Review and perspective

International Nuclear Information System (INIS)

Breitung, W.

1982-03-01

Vapor pressures of liquid oxide reactor fuels are among the most important material data required for theoretical analyses of Hypothetical Core Disruptive Accidents in Fast Breeder Reactors. This report is an attempt to completely summarize and critically review the numerous theoretical and experimental results published for the pressure-temperature and pressure-energy relation of unirradiated UO 2 and (U,Pu)O 2 . First - to define the research goal - the precision in the saturation vapor pressure is quantified which is required for the purpose of HCDA calculations. Then the various theoretical and experimental methods used for the determination of p-T and p-U data are reviewed with respect to their principles, results and uncertainties. The achievements of the individual methods are discussed in the light of the research goal and - in view of the widely scattered data - recommendations are made concerning the p-T and p-U relation of UO 2 . Finally, the most important future research areas are identified, including some specific research proposals which aim at reducing the still large uncertainties in fuel vapor pressures down to the desired level. (orig.) [de

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

Science.gov (United States)

Ambarita, H.; Sihombing, H. V.

2018-03-01

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

Indirect Determination of Vapor Pressures by Capillary Gas-Liquid Chromatography: Analysis of the Reference Vapor-Pressure Data and Their Treatment

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Koutek, Bohumír; Fulem, M.; Hoskovec, Michal

2012-01-01

Roč. 57, č. 5 (2012), s. 1349-1368 ISSN 0021-9568 R&D Projects: GA ČR GA203/09/1327 Institutional research plan: CEZ:AV0Z40550506 Keywords : vapor pressures * capillary gas–liquid chromatography * reference data * relative retention time Subject RIV: CC - Organic Chemistry Impact factor: 2.004, year: 2012

Temperature/pressure and water vapor sounding with microwave spectroscopy

Science.gov (United States)

Muhleman, D. O.; Janssen, M. A.; Clancy, R. T.; Gulkis, S.; Mccleese, D. J.; Zurek, R.; Haberle, R. M.; Frerking, M.

1992-01-01

Two intense microwave spectra lines exist in the martian atmosphere that allow unique sounding capabilities: water vapor at 183 GHz and the (2-1) rotational line of CO at 230 GHz. Microwave spectra line sounding is a well-developed technique for the Earth's atmosphere for sounding from above from spacecraft and airplanes, and from below from fixed surface sites. Two simple instruments for temperature sounding on Mars (the CO line) and water vapor measurements are described. The surface sounder proposed for the MESUR sites is designed to study the boundary layer water vapor distribution and the temperature/pressure profiles with vertical resolution of 0.25 km up to 1 km with reduced resolution above approaching a scale height. The water channel will be sensitive to a few tenths of a micrometer of water and the temperature profile will be retrieved to an accuracy between 1 and 2 K. The latter is routinely done on the Earth using oxygen lines near 60 GHz. The measurements are done with a single-channel heterodyne receiver looking into a 10-cm mirror that is canned through a range of elevation angles plus a target load. The frequency of the receiver is sweep across the water and CO lines generating the two spectra at about 1-hr intervals throughout the mission. The mass and power for the proposed instrument are 2 kg and 5-8 W continuously. The measurements are completely immune to the atmospheric dust and ice particle loads. It was felt that these measurements are the ultimate ones to properly study the martian boundary layer from the surface to a few kilometers. Sounding from above requires an orbiting spacecraft with multichannel microwave spectrometers such as the instrument proposed for MO by a subset of the authors, a putative MESUR orbiter, and a proposed Discovery mission called MOES. Such an instrument can be built with less than 10 kg and use less than 15 W. The obvious advantage of this approach is that the entire atmosphere can be sounded for temperature and

Vapor pressures, thermodynamic stability, and fluorescence properties of three 2,6-alkyl naphthalenes.

Science.gov (United States)

Santos, Ana Filipa L O M; Oliveira, Juliana A S A; Ribeiro da Silva, Maria D M C; Monte, Manuel J S

2016-03-01

This work reports the experimental determination of relevant thermodynamic properties and the characterization of luminescence properties of the following polycyclic aromatic hydrocarbons (PAHs): 2,6-diethylnaphthalene, 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene. The standard (p(o) = 0.1 MPa) molar enthalpies of combustion, ΔcHm(o), of the three compounds were determined using static bomb combustion calorimetry. The vapor pressures of the crystalline phase of 2,6-diisopropylnaphthalene and 2,6-di-tert-butylnaphthalene were measured at different temperatures using the Knudsen effusion method and the vapor pressures of both liquid and crystalline phases of 2,6-diethylnaphthalene were measured by means of a static method. The temperatures and the molar enthalpies of fusion of the three compounds were determined using differential scanning calorimetry. The gas-phase molar heat capacities and absolute entropies of the three 2,6-dialkylnaphthalenes studied were determined computationally. The thermodynamic stability of the compounds in both the crystalline and gaseous phases was evaluated by the determination of the Gibbs energies of formation and compared with the ones reported in the literature for 2,6-dimethylnaphthalene. From fluorescence spectroscopy measurements, the optical properties of the compounds studied and of naphthalene were evaluated in solution and in the solid state. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

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

1982-01-01

Vapor pressures and vapor compositions in equilibrium with a hypostoichiometric uranium-plutonium dioxide condensed phase (U/sub 1-y/Pu/sub y/)O/sub 2-x/, as functions of T, x, and y, have been calculated for 0.0 less than or equal to x less than or equal to 0.1, 0.0 less than or equal to y less than or equal to 0.3, and for the temperature range 2500 less than or equal to T less than or equal to 6000 K. The range of compositions and temperatures was limited to the region of interest to reactor safety analysis. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen potential model to obtain partial pressures of O, O 2 , Pu, PuO, PuO 2 , U, UO, UO 2 , and UO 3 as functions of T, x, and y

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

Science.gov (United States)

Dearden, John C

2003-08-01

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

Determination of saturation pressure and enthalpy of vaporization of semi-volatile aerosols: the integrated volume mentod

Science.gov (United States)

This study presents the integrated volume method for estimating saturation pressure and enthalpy of vaporization of a whole aerosol distribution. We measure the change of total volume of an aerosol distribution between a reference state and several heated states, with the heating...

Vapor pressure, heat capacities, and phase transitions of tetrakis(tert-butoxy)hafnium

Czech Academy of Sciences Publication Activity Database

Fulem, Michal; Růžička, K.

2011-01-01

Roč. 311, Dec. (2011), s. 25-29 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z10100521 Keywords : tetrakis(tert-butoxy)hafnium * MO precursor * vapor pressure * heat capacity * vaporization enthalpy * enthalpy of fusion Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.139, year: 2011

Impacts of Changes of Indoor Air Pressure and Air Exchange Rate in Vapor Intrusion Scenarios.

Science.gov (United States)

Shen, Rui; Suuberg, Eric M

2016-02-01

There has, in recent years, been increasing interest in understanding the transport processes of relevance in vapor intrusion of volatile organic compounds (VOCs) into buildings on contaminated sites. These studies have included fate and transport modeling. Most such models have simplified the prediction of indoor air contaminant vapor concentrations by employing a steady state assumption, which often results in difficulties in reconciling these results with field measurements. This paper focuses on two major factors that may be subject to significant transients in vapor intrusion situations, including the indoor air pressure and the air exchange rate in the subject building. A three-dimensional finite element model was employed with consideration of daily and seasonal variations in these factors. From the results, the variations of indoor air pressure and air exchange rate are seen to contribute to significant variations in indoor air contaminant vapor concentrations. Depending upon the assumptions regarding the variations in these parameters, the results are only sometimes consistent with the reports of several orders of magnitude in indoor air concentration variations from field studies. The results point to the need to examine more carefully the interplay of these factors in order to quantitatively understand the variations in potential indoor air exposures.

Physico-chemical characterization antituberculosis thioacetazone: Vapor pressure, solubility and lipophilicity

International Nuclear Information System (INIS)

Sharapova, Angelica; Ol'khovich, Marina; Blokhina, Svetlana; Perlovich, German

2017-01-01

Highlights: • Vapor pressures of antituberculosis thioacetazone were determined by transpiration method. • Solubilities of the TAZ in four modeling solvents were measured at different temperatures. • Temperature dependence of octanol/buffer pH 7.4 partition coefficients was obtained. • Thermodynamics parameters of solubility, sublimation, solvation and transfer were calculated. - Abstract: Vapor pressure of thioacetazone (TAZ) has been determined in the temperature range of 404.15–429.15 K by the transpiration method. The obtained data were used to calculate the standard molar enthalpy of sublimation that was found to be 164.1 kJ/mol at T = 298.15 K. The drug solubility was measured at seven temperatures from 288.15 to 318.15 K in modeling solvents: octanol, hexane and aqueous buffers pH 2.0 and 7.4 by the saturation shake-flask method by using spectrophotometric analysis. It has been found that TAZ has poor solubility in hexane and buffer solutions and limited solubility in octanol. The experimental data were well correlated by van’t Hoff and modified Apelblat equations. A temperature dependence of TAZ partition coefficient in the octanol/buffer pH 7.4 system has been derived. The partition coefficient value in this system (logP = 1.82) refers to the optimal interval for oral absorption drugs. The thermodynamic parameters of sublimation, solubility, solvation and transfer have been determined based on experimental data. The dominant effect of enthalpy and entropy contributions to the Gibbs energy of the investigated processes has been revealed.

A study on vapor explosions

International Nuclear Information System (INIS)

Takagi, N.; Shoji, M.

1979-01-01

An experimental study was carried out for vapor explosions of molten tin falling in water. For various initial metal temperatures and subcooling of water, transient pressure of the explosions, relative frequency of the explosions and the position where the explosions occur were measured in detail. The influence of ambient pressure was also investigated. From the results, it was concluded that the vapor explosion is closely related to the collapse of a vapor film around the molten metal. (author)

Evaluation of a Fully Automated Analyzer for Rapid Measurement of Water Vapor Sorption Isotherms for Applications in Soil Science

DEFF Research Database (Denmark)

Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

2014-01-01

The characterization and description of important soil processes such as water vapor transport, volatilization of pesticides, and hysteresis require accurate means for measuring the soil water characteristic (SWC) at low water potentials. Until recently, measurement of the SWC at low water...... potentials was constrained by hydraulic decoupling and long equilibration times when pressure plates or single-point, chilled-mirror instruments were used. A new, fully automated Vapor Sorption Analyzer (VSA) helps to overcome these challenges and allows faster measurement of highly detailed water vapor...

Pursuing atmospheric water vapor retrieval through NDSA measurements between two LEO satellites: evaluation of estimation errors in spectral sensitivity measurements

Science.gov (United States)

Facheris, L.; Cuccoli, F.; Argenti, F.

2008-10-01

NDSA (Normalized Differential Spectral Absorption) is a novel differential measurement method to estimate the total content of water vapor (IWV, Integrated Water Vapor) along a tropospheric propagation path between two Low Earth Orbit (LEO) satellites. A transmitter onboard the first LEO satellite and a receiver onboard the second one are required. The NDSA approach is based on the simultaneous estimate of the total attenuations at two relatively close frequencies in the Ku/K bands and of a "spectral sensitivity parameter" that can be directly converted into IWV. The spectral sensitivity has the potential to emphasize the water vapor contribution, to cancel out all spectrally flat unwanted contributions and to limit the impairments due to tropospheric scintillation. Based on a previous Monte Carlo simulation approach, through which we analyzed the measurement accuracy of the spectral sensitivity parameter at three different and complementary frequencies, in this work we examine such accuracy for a particularly critical atmospheric status as simulated through the pressure, temperature and water vapor profiles measured by a high resolution radiosonde. We confirm the validity of an approximate expression of the accuracy and discuss the problems that may arise when tropospheric water vapor concentration is lower than expected.

Measurement of the enthalpies of vaporization and sublimation of solids aromatic hydrocarbons by differential scanning calorimetry

International Nuclear Information System (INIS)

Rojas, Aaron; Orozco, Eulogio

2003-01-01

An experimental procedure is proposed for direct measurement of the heat involved in the vaporization of a solid organic compound above its normal melting temperature. This technique consists on the fusion of a solid aromatic hydrocarbon, which is then vaporized by a sudden decrease of the pressure. The direct register of heat flow as function of time by differential scanning calorimetry allows the quantifying of the enthalpy of vaporization of compounds such as phenanthrene, β-naphthol, pyrene, and anthracene. Enthalpies of vaporization were measured in an isothermal mode over a range of temperatures from 10 to 20 K above the melting temperatures of each compound, while enthalpies of fusion were determined from separate experiments performed in a scanning mode. Enthalpies of sublimation are computed from results of fusion and vaporization, and then compared with results from the literature, which currently are obtained by calorimetric or indirect techniques

Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

International Nuclear Information System (INIS)

Johnson, Kyle W.; Guruvenket, Srinivasan; Sailer, Robert A.; Ahrenkiel, S. Phillip; Schulz, Douglas L.

2013-01-01

Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H 2 O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF 2 . • Carbonaceous contamination from the precursor was minimal

Highly ionized physical vapor deposition plasma source working at very low pressure

Science.gov (United States)

Stranak, V.; Herrendorf, A.-P.; Drache, S.; Cada, M.; Hubicka, Z.; Tichy, M.; Hippler, R.

2012-04-01

Highly ionized discharge for physical vapor deposition at very low pressure is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of pressure during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical pressure ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti+ and Ti++ peaks are observed in the mass scan spectra). This corresponds well with high plasma density ne ˜ 1018 m-3, measured during the HiPIMS pulse.

Highly ionized physical vapor deposition plasma source working at very low pressure

International Nuclear Information System (INIS)

Stranak, V.; Herrendorf, A.-P.; Drache, S.; Hippler, R.; Cada, M.; Hubicka, Z.; Tichy, M.

2012-01-01

Highly ionized discharge for physical vapor deposition at very low pressure is presented in the paper. The discharge is generated by electron cyclotron wave resonance (ECWR) which assists with ignition of high power impulse magnetron sputtering (HiPIMS) discharge. The magnetron gun (with Ti target) was built into the single-turn coil RF electrode of the ECWR facility. ECWR assistance provides pre-ionization effect which allows significant reduction of pressure during HiPIMS operation down to p = 0.05 Pa; this is nearly more than an order of magnitude lower than at typical pressure ranges of HiPIMS discharges. We can confirm that nearly all sputtered particles are ionized (only Ti + and Ti ++ peaks are observed in the mass scan spectra). This corresponds well with high plasma density n e ∼ 10 18 m -3 , measured during the HiPIMS pulse.

Vapor pressures and enthalpies of vaporization of a series of 1- and 2-halogenated naphthalenes

International Nuclear Information System (INIS)

Verevkin, Sergey P.

2003-01-01

Molar enthalpies of vaporization, Δ l g H m 0 , of 1-methyl-naphthalene, 1-chloro-napthalene, 2-chloro-naphthalene, 1-bromo-naphthalene, 2-bromo-naphthalene, and 1-iodo-naphthalene, as well as molar enthalpies of sublimation, Δ s g H m 0 , of 2-chloro-naphthalene and 2-bromo-naphthalene have been obtained from the temperature dependence of the vapor pressure determined with the transpiration method. These values and the correlation gas-chromatography method, based on the Kovat's index, have been used to determine Δ l g H m 0 and Δ s g H m 0 of 2-iodo-naphthalene. Results obtained in this work have been compared with those from the literature and found consistent

High temperature measurement of water vapor absorption

Science.gov (United States)

Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

1985-01-01

An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

Measurement of vapor behavior in tight-lattice bundles by neutron radiography

International Nuclear Information System (INIS)

Kureta, Masatoshi; Akimoto, Hajime

2004-01-01

Three-dimensional and instantaneous void fractions in tight-lattice 7-rod and 14-rod bundles were measured by neutron radiography in order to make clear the flow behavior and to verify the advanced fine-mesh numerical analysis codes for the R and D of the Reduced-Moderation Water Reactors (RMWR). Time-averaged 3D void fraction distribution is evaluated with the spatial resolution of 0.1 - 0.2 mm using neutron tomography, and consecutive change of vapor behavior is observed quantitatively with time step of 1 ms using high-frame-rate neutron radiography (HFR-NR). In this paper, void fraction distribution and vapor behavior of flow boiling of water in tight-lattice rod bundles are focused on and discussed based on the obtained results. 'High void fraction spot', 'void drift phenomenon', and 'vapor chimney' were observed under atmospheric pressure conditions. Here, 'high void fraction spot' indicates that high void fraction regions are appeared between adjacent rods, narrow space, at/near point of net vapor generation region. 'Void drift' and 'vapor chimney' represent that high void fraction region moves to wide triangular space and is formed a vapor flow channel so-called 'vapor chimney'. It was confirmed from the time-averaged 3D data that void fraction in the center is higher than that in the periphery. On the other hand, it was found from the HFR-NR experiments that big vapor bubbles and/or cluster flow upward intermittently not only in the center but in the periphery of the channel and, therefore, point of net vapor generation is scattered statistically in wide region. (author)

Calculation of vapor pressures of oxide fuels up to 5,000 K for equilibrium and nonequilibrium evaporation

International Nuclear Information System (INIS)

Breitung, W.

1975-06-01

In the first part of this work the evaporation kinetics of multicomponent systems is studied with UO 2 as the example. The evaporation, which is generally incongruent, implies that two opposing types of steady-state evaporation must be distinguished: equilibrium evaporation and 'forced congruent' evaporation. The two types of evaporation indicated entail different vapor pressures. In some prompt critical reactor incidents forced congruent evaporation must be anticipated. The second part of this work contains the calculation of the vapor pressures of UOsub(2+-x) and (U,Pu)Osub(2+-x) for both types of evaporation up to temperature of 5,000 K. The calculating procedures are based on the method of Rand and Markin (1967) incorporating the recent thermodynamic data. The agreement between the measured and calculated total pressures is good for the ranges of temperature and stoichiometry for which experimental results are available. This supports the results calculated for higher temperature ranges. (orig./UA) [de

Vapor pressures of solid and liquid xanthene and phenoxathiin from effusion and static studies

Czech Academy of Sciences Publication Activity Database

Monte, M.J.S.; Santos, L.M.N.B.F.; Sousa, C.A.D.; Fulem, Michal

2008-01-01

Roč. 53, č. 8 (2008), s. 1922-1926 ISSN 0021-9568 Institutional research plan: CEZ:AV0Z10100521 Keywords : vapor pressure * xanthene * phenoxanthiin * sublimation and vaporization enthalpy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.063, year: 2008

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

Energy Technology Data Exchange (ETDEWEB)

Inoue, Akira; Fujii, Yoshifumi; Matsuzaki, Mitsuo [Tokyo Institute of Technology (Japan)

1995-09-01

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

Vapor Pressure of N,N’-Diisopropylcarbodiimide (DICDI)

Science.gov (United States)

2016-02-01

11. Furumoto, S. The Synthesis of Carbodiimides from N,N-Disubstituted Thioureas and 2- Chloro-4,6-dimethylpyrimidine, 2,4-Dichloropyrimidine or...N-Phenylbenzimidoyl Chloride . Journal of Synthetic Organic Chemistry, Japan 1975, 33, 748–752. 12. Kagami, H.; Hanzawa, N.; Suzuki, N.; Yamaguchi...25. Brozena, A.; Buchanan, J.H.; Miles, R.W., Jr.; Williams, B.R.; Hulet, M.S. Vapor Pressure of Triethyl and Tri-n- Propyl Phosphates and Diethyl

Determination of Water Vapor Pressure Over Corrosive Chemicals Versus Temperature Using Raman Spectroscopy as Exemplified with 85.5% Phosphoric Acid

DEFF Research Database (Denmark)

Rodier, Marion; Li, Qingfeng; Berg, Rolf W.

2016-01-01

A method to determine the water vapor pressure over a corrosive substance was developed and tested with 85.5 ± 0.4% phosphoric acid. The water vapor pressure was obtained at a range of temperatures from ∼25 ℃ to ∼200 ℃ using Raman spectrometry. The acid was placed in an ampoule and sealed...... with a reference gas (either hydrogen or methane) at a known pressure (typically ∼0.5 bar). By comparing the Raman signals from the water vapor and the references, the water pressure was determined as a function of temperature. A considerable amount of data on the vapor pressure of phosphoric acid are available...... in the literature, to which our results could successfully be compared. A record value of the vapor pressure, 3.40 bar, was determined at 210 ℃. The method required a determination of the precise Raman scattering ratios between the substance, water, and the used reference gas, hydrogen or methane. In our case...

A systematic study of atmospheric pressure chemical vapor deposition growth of large-area monolayer graphene.

Science.gov (United States)

Liu, Lixin; Zhou, Hailong; Cheng, Rui; Chen, Yu; Lin, Yung-Chen; Qu, Yongquan; Bai, Jingwei; Ivanov, Ivan A; Liu, Gang; Huang, Yu; Duan, Xiangfeng

2012-01-28

Graphene has attracted considerable interest as a potential material for future electronics. Although mechanical peel is known to produce high quality graphene flakes, practical applications require continuous graphene layers over a large area. The catalyst-assisted chemical vapor deposition (CVD) is a promising synthetic method to deliver wafer-sized graphene. Here we present a systematic study on the nucleation and growth of crystallized graphene domains in an atmospheric pressure chemical vapor deposition (APCVD) process. Parametric studies show that the mean size of the graphene domains increases with increasing growth temperature and CH 4 partial pressure, while the density of domains decreases with increasing growth temperature and is independent of the CH 4 partial pressure. Our studies show that nucleation of graphene domains on copper substrate is highly dependent on the initial annealing temperature. A two-step synthetic process with higher initial annealing temperature but lower growth temperature is developed to reduce domain density and achieve high quality full-surface coverage of monolayer graphene films. Electrical transport measurements demonstrate that the resulting graphene exhibits a high carrier mobility of up to 3000 cm 2 V -1 s -1 at room temperature.

Assessment of Fluctuation Patterns Similarity in Temperature and Vapor Pressure Using Discrete Wavelet Transform

Directory of Open Access Journals (Sweden)

A. Araghi

2014-12-01

Full Text Available Period and trend are two main effective and important factors in hydro-climatological time series and because of this importance, different methods have been introduced and applied to study of them, until now. Most of these methods are statistical basis and they are classified in the non-parametric tests. Wavelet transform is a mathematical based powerful method which has been widely used in signal processing and time series analysis in recent years. In this research, trend and main periodic patterns similarity in temperature and vapor pressure has been studied in Babolsar, Tehran and Shahroud synoptic stations during 55 years period (from 1956 to 2010, using wavelet method and the sequential Mann-Kendall trend test. The results show that long term fluctuation patterns in temperature and vapor pressure have more correlations in the arid and semi-arid climates, as well as short term oscillation patterns in temperature and vapor pressure in the humid climates, and these dominant periods increase with the aridity of region.

Reid Vapor Pressure (RVP) of Gasoline Spreadsheet Example Key for Requirements at 40 CFR 80.47(g) and 80.47(l)

Science.gov (United States)

This guidance deals with the self-qualification of analytical test methods at a testing facility for measuring Reid Vapor Pressure (RVP) of gasoline to meet precision requirements codified in regulations.

Vapor pressures and standard molar enthalpies, entropies, and Gibbs free energies of sublimation of 2,4- and 3,4-dinitrobenzoic acids

International Nuclear Information System (INIS)

Vecchio, Stefano; Brunetti, Bruno

2009-01-01

The vapor pressures of the solid and liquid 2,4- and 3,4-dinitrobenzoic acids were determined by torsion-effusion and thermogravimetry under both isothermal and non-isothermal conditions, respectively. From the temperature dependence of vapor pressure derived by the experimental torsion-effusion and thermogravimetry data the molar enthalpies of sublimation Δ cr g H m 0 ( ) and vaporization Δ l g H m 0 ( ) were determined, respectively, at the middle of the respective temperature intervals. The melting temperatures and the molar enthalpies of fusion of these compounds were measured by d.s.c. Finally, the results obtained by all the methods proposed were corrected at the reference temperature of 298.15 K using the estimated heat capacity differences between gas and liquid for vaporization experiments and the estimated heat capacity differences between gas and solid for sublimation experiments. Therefore, the averages of the standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs free energies of sublimation at 298.15 K, have been derived.

Dual-pressure vaporization Kalina cycle for cascade reclaiming heat resource for power generation

International Nuclear Information System (INIS)

Guo, Zhanwei; Zhang, Zhi; Chen, Yaping; Wu, Jiafeng; Dong, Cong

2015-01-01

Graphical abstract: Schematic of the dual-pressure evaporation Kalina cycle. - Highlights: • Dual-pressure vaporization Kalina cycle for high-grade heat resource is investigated. • It is designed with 2nd evaporation branch for cascade utilization of heat resource. • Work and basic concentrations, dew point temperature of evaporation are optimized. • Power recovery efficiency of proposed cycle is 17% higher than that of Kalina cycle. • Dual-p vaporization Kalina cycle fits reclaiming heat resource higher than 350 °C. - Abstract: To further improve the cycle efficiency with the heat transfer curves between higher than 350 °C heat resource and the evaporating working medium of the Kalina cycle and to reduce the exhaust temperature of heat resource, the dual-pressure vaporization Kalina cycle for cascade utilization of high-to-mid grade heat resource is proposed. The optimization was conducted for parameters in this modified Kalina cycle such as concentrations of work solution and basic solution, evaporation dew point temperature. Under the conditions of inlet temperatures of heat resource and cooling water of respectively 400 °C and 25 °C and the constraints of proper heat transfer pinch point temperature differences, the maximum evaporation pressure not exceeds 20 MPa, the vapour quality at the turbine outlet is greater than 0.85 and the exhaust temperature of heat resource is not lower than 90 °C, the optimum parameters are obtained that the work and basic concentrations are 0.45 and 0.272 respectively, the dew point temperature of evaporation is 300 °C, and the corresponding power recovery efficiency of the dual-pressure vaporization Kalina cycle reaches 27%, which is 17% higher than that of the Kalina cycle with optimum parameters.

Vapor Pressure of Selected Aliphatic Alcohols by Ebulliometry. Part 1

Czech Academy of Sciences Publication Activity Database

Čenský, M.; Roháč, V.; Růžička, K.; Fulem, M.; Aim, Karel

2010-01-01

Roč. 298, č. 2 (2010), s. 192-198 ISSN 0378-3812 R&D Projects: GA AV ČR IAA400720710 Institutional research plan: CEZ:AV0Z40720504 Keywords : vapor pressure * ebulliometry * aliphatic alcohols Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.253, year: 2010

Vapour pressures and heat capacity measurements on the C7-C9 secondary aliphatic alcohols

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Schick, Christoph

2007-01-01

Molar enthalpies of vaporization of secondary C 7 -C 9 alkanols were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. The measured data sets were checked for internal consistency successfully. A large number of the primary experimental results on temperature dependences of vapour pressures of secondary alcohols have been collected from the literature and have been treated uniform in order to derive their vaporization enthalpies at the reference temperature 298.15 K. This collection, together with our experimental results, have helped to ascertain the database for branched aliphatic alcohols

Development of a device to valuate the effect of ethanol on the vapor pressure and vaporization enthalpy of fuel gasolines

OpenAIRE

Cataluña, Renato; Silva, Rosângela

2006-01-01

The quality of the gasoline utilized for fueling internal combustion engines with spark ignition is directly affected by the gasoline's properties. Thus, the fuel's properties must be in perfect equilibrium to allow the engine to perform optimally, not only insofar as fuel consumption is concerned, but also in order to reduce the emission of pollutants. Vapor pressure and vaporization enthalpy are important properties of a gasoline determining the fuel's behavior under different operating con...

Vapor pressures and isopiestic molalities of concentrated CaCl2(aq), CaBr2(aq), and NaCl(aq) to T = 523 K

International Nuclear Information System (INIS)

Gruszkiewicz, Miroslaw S.; Simonson, John M.

2005-01-01

The Oak Ridge National Laboratory high-temperature isopiestic apparatus was outfitted with precise pressure gauges to allow for direct vapor pressure measurements. Vapor pressures over concentrated solutions of CaCl 2 (aq), and CaBr 2 (aq) were measured at temperatures between (380.15 and 523.15) K in the range of water activities between 0.2 and 0.85. Isopiestic molalities were used to determine osmotic coefficients at the conditions where NaCl reference standard solutions remained undersaturated. The main goal of this work was to improve the accuracy of isopiestic comparisons based on the calcium chloride reference standard. Osmotic coefficients for CaCl 2 (aq) and CaBr 2 (aq) calculated from both isopiestic and direct vapor pressure results were combined with the literature data and used to build general thermodynamic models based on a variant of extended Pitzer ion-interaction equations and valid at the saturation pressure of water. While these empirical models approach the accuracy of the experimental data in a wider range of concentrations and temperatures than any previously published equations, considerable amounts of accurate data and a substantial effort are required in order to obtain a satisfactory representation using power series-based virial equations. The effect of experimental uncertainties on the accuracy of the direct vapor pressure results is discussed, including in particular the error caused by the presence in the apparatus of a small amount of CO 2 . The substantial decrease of the solubility product of CaCO 3 in concentrated chloride solutions at temperatures above 423 K is a serious defect of calcium chloride as a water activity reference standard

Influence of the helium-pressure on diode-pumped alkali-vapor laser

Science.gov (United States)

Gao, Fei; Chen, Fei; Xie, Ji-jiang; Zhang, Lai-ming; Li, Dian-jun; Yang, Gui-long; Guo, Jing

2013-05-01

Diode-pumped alkali-vapor laser (DPAL) is a kind of laser attracted much attention for its merits, such as high quantum efficiency, excellent beam quality, favorable thermal management, and potential scalability to high power and so on. Based on the rate-equation theory of end-pumped DPAL, the performances of DPAL using Cs-vapor collisionally broadened by helium are simulated and studied. With the increase of helium pressure, the numerical results show that: 1) the absorption line-width increases and the stimulated absorption cross-section decreases contrarily; 2) the threshold pumping power decreases to minimum and then rolls over to increase linearly; 3) the absorption efficiency rises to maximum initially due to enough large stimulated absorption cross-section in the far wings of collisionally broadened D2 transition (absorption transition), and then begins to reduce; 4) an optimal value of helium pressure exists to obtain the highest output power, leading to an optimal optical-optical efficiency. Furthermore, to generate the self-oscillation of laser, a critical value of helium pressure occurs when small-signal gain equals to the threshold gain.

Contribution of water vapor pressure to pressurization of plutonium dioxide storage containers

Science.gov (United States)

Veirs, D. Kirk; Morris, John S.; Spearing, Dane R.

2000-07-01

Pressurization of long-term storage containers filled with materials meeting the US DOE storage standard is of concern.1,2 For example, temperatures within storage containers packaged according to the standard and contained in 9975 shipping packages that are stored in full view of the sun can reach internal temperatures of 250 °C.3 Twenty five grams of water (0.5 wt.%) at 250 °C in the storage container with no other material present would result in a pressure of 412 psia, which is limited by the amount of water. The pressure due to the water can be substantially reduced due to interactions with the stored material. Studies of the adsorption of water by PuO2 and surface interactions of water with PuO2 show that adsorption of 0.5 wt.% of water is feasible under many conditions and probable under high humidity conditions.4,5,6 However, no data are available on the vapor pressure of water over plutonium dioxide containing materials that have been exposed to water.

Water vapor measurements in the 0.94 micron absorption band - Calibration, measurements and data applications

Science.gov (United States)

Reagan, J. A.; Thome, K.; Herman, B.; Gall, R.

1987-01-01

This paper describes methods and presents results for sensing the columnar content of atmospheric water vapor via differential solar transmission measurements in and adjacent to the 0.94-micron water-vapor absorption band. Calibration and measurement techniques are presented for obtaining the water vapor transmission from the radiometer measurements. Models are also presented for retrieving the columnar water vapor amount from the estimated transmission. Example retrievals are presented for radiometer measurements made during the 1986 Arizona Monsoon Season to track temporal variations in columnar water vapor amount.

High-pressure catalytic chemical vapor deposition of ferromagnetic ruthenium-containing carbon nanostructures

Energy Technology Data Exchange (ETDEWEB)

Khavrus, Vyacheslav O., E-mail: V.Khavrus@ifw-dresden.de; Ibrahim, E. M. M.; Bachmatiuk, Alicja; Ruemmeli, Mark H.; Wolter, A. U. B.; Hampel, Silke; Leonhardt, Albrecht [IFW Dresden (Germany)

2012-06-15

We report on the high-pressure catalytic chemical vapor deposition (CCVD) of ruthenium nanoparticles (NPs) and single-walled carbon nanotubes (SWCNTs) by means of gas-phase decomposition of acetonitrile and ruthenocene in a tubular quartz flow reactor at 950 Degree-Sign C and at elevated pressures (between 2 and 8 bar). The deposited material consists of Ru metal cores with sizes ranging between 1 and 3 nm surrounded by a carbon matrix. The high-pressure CCVD seems to be an effective route to obtain composite materials containing metallic NPs, Ru in this work, inside a nanostructured carbon matrix protecting them from oxidation in ambient air. We find that in contradiction to the weak paramagnetic properties characterizing bulk ruthenium, the synthesized samples are ferromagnetic as predicted for nanosized particles of nonmagnetic materials. At low pressure, the very small ruthenium catalyst particles are able to catalyze growth of SWCNTs. Their yield decreases with increasing reaction pressure. Transmission electron microscopy, selected area energy-dispersive X-ray analysis, Raman spectroscopy, and magnetic measurements were used to analyze and confirm properties of the synthesized NPs and nanotubes. A discussion on the growth mechanism of the Ru-containing nanostructures is presented.

Vapor Pressure Data and Analysis for Selected Organophosphorus Compounds, CMMP, DPMP, DMEP, and DEEP: Extrapolation of High-Temperature Data

Science.gov (United States)

2018-04-01

comparison. The correlation equations are presented using two common units systems , one with temperature given in kelvin (T) and pressure in pascal...This report documents vapor pressure data and correlations for four phosphonate ester compounds that have molecular structures similar to those of...Antoine equation Clausius–Clapeyron equation Enthalpy of vaporization Volatility Differential scanning calorimetry (DSC) Vapor saturation Normal boiling

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

Science.gov (United States)

Stewart, Mark E. M.

2017-01-01

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

The vaporization enthalpies and vapor pressures of fatty acid methyl esters C18, C21 to C23, and C25 to C29 by correlation - gas chromatography

International Nuclear Information System (INIS)

Chickos, James S.; Zhao Hui; Nichols, Gary

2004-01-01

Vapor pressures and vaporization enthalpies for methyl heptadecanoate and methyl heneicosanoate to methyl octacosanoate exclusive of methyl tricosanoate are evaluated as a function of temperature over the temperature range T = 298.15-450 K by correlation gas chromatography. The results are generated by an extrapolative process using literature values for methyl tetradecanoate to methyl eicosanoate as standards. Relationships for calculating vapor pressures of the title compounds from T = 298.15 to 450 K are provided. Experimental fusion enthalpies are also reported for the methyl esters from methyl hexadecanoate to methyl octacosanoate excluding methyl tridecanoate. Vaporization enthalpies and fusion enthalpies adjusted for temperature to T = 298.15 K are combined to provide sublimation enthalpies. The results are compared to available literature values. A rationale for the linear relationship observed between enthalpies of vaporization and enthalpies of transfer from solution to the vapor is also provided

Numerical simulation of vapor flow and pressure drop across the demister of MSF desalination plant

International Nuclear Information System (INIS)

Janajreh, I.; Hasania, A.; Fath, H.

2013-01-01

Highlights: ► Porous media was used to simulate the pressure drop across desalination demister. ► Simulation results plausibly compared with experimental results. ► FC inlet Velocity distribution has no effect on the demister pressure drop. ► Demister inertial resistance affects pressure drop more than viscous resistance. - Abstract: This paper presents a numerical simulation of the water vapor flow in an MSF flash chamber along with the pressure drop across the demister. The demister is a simple porous blanket of metal wires mesh (usually made of stainless steel wires) which retains liquid droplets entrained by the vapor momentum to enhance the quality of the product water. Two main areas of concern in wire mesh mist eliminators are; (i) the pressure drop and (ii) the mist removal efficiency. The present simulation focuses only on the pressure drop across the demister. The simulation is carried out considering a full scale flashing chamber of a typical operational MSF desalination plant and of a real industrial demister dimensions. The study simulates the demister as porous media flow. It takes into account the vapor velocity, the dimension of the demister, its porosity and wire thickness. The obtained pressure drop was found to be within a reasonable agreement with the published literature data and it follows a trend compatible with Ergun’s equation as well as the empirical correlation of Svendsen.

Thermodynamics and Kinetics of Silicate Vaporization

Science.gov (United States)

Jacobson, Nathan S.; Costa, Gustavo C. C.

2015-01-01

Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

The functional dependence of canopy conductance on water vapor pressure deficit revisited

Science.gov (United States)

Fuchs, Marcel; Stanghellini, Cecilia

2018-03-01

Current research seeking to relate between ambient water vapor deficit (D) and foliage conductance (g F ) derives a canopy conductance (g W ) from measured transpiration by inverting the coupled transpiration model to yield g W = m - n ln(D) where m and n are fitting parameters. In contrast, this paper demonstrates that the relation between coupled g W and D is g W = AP/D + B, where P is the barometric pressure, A is the radiative term, and B is the convective term coefficient of the Penman-Monteith equation. A and B are functions of g F and of meteorological parameters but are mathematically independent of D. Keeping A and B constant implies constancy of g F . With these premises, the derived g W is a hyperbolic function of D resembling the logarithmic expression, in contradiction with the pre-set constancy of g F . Calculations with random inputs that ensure independence between g F and D reproduce published experimental scatter plots that display a dependence between g W and D in contradiction with the premises. For this reason, the dependence of g W on D is a computational artifact unrelated to any real effect of ambient humidity on stomatal aperture and closure. Data collected in a maize field confirm the inadequacy of the logarithmic function to quantify the relation between canopy conductance and vapor pressure deficit.

Prediction of the liquid-vapor equilibrium pressure using the quasi-Gaussian entropy theory

NARCIS (Netherlands)

Amadei, A; Roccatano, D; Apol, M.E F; Berendsen, H.J.C.; Di Nola, A.

1996-01-01

We derived a method to evaluate the liquid-vapor equilibrium pressure, with high accuracy over a large range of temperature, using the quasi-Gaussian entropy theory. The final expression that we obtain for the equilibrium pressure as a function of the temperature can be considered as a very accurate

Characterization of the TIP4P-Ew water model: vapor pressure and boiling point.

Science.gov (United States)

Horn, Hans W; Swope, William C; Pitera, Jed W

2005-11-15

The liquid-vapor-phase equilibrium properties of the previously developed TIP4P-Ew water model have been studied using thermodynamic integration free-energy simulation techniques in the temperature range of 274-400 K. We stress that free-energy results from simulations need to be corrected in order to be compared to the experiment. This is due to the fact that the thermodynamic end states accessible through simulations correspond to fictitious substances (classical rigid liquids and classical rigid ideal gases) while experiments operate on real substances (liquids and real gases, with quantum effects). After applying analytical corrections the vapor pressure curve obtained from simulated free-energy changes is in excellent agreement with the experimental vapor pressure curve. The boiling point of TIP4P-Ew water under ambient pressure is found to be at 370.3+/-1.9 K, about 7 K higher than the boiling point of TIP4P water (363.7+/-5.1 K; from simulations that employ finite range treatment of electrostatic and Lennard-Jones interactions). This is in contrast to the approximately +15 K by which the temperature of the density maximum and the melting temperature of TIP4P-Ew are shifted relative to TIP4P, indicating that the temperature range over which the liquid phase of TIP4P-Ew is stable is narrower than that of TIP4P and resembles more that of real water. The quality of the vapor pressure results highlights the success of TIP4P-Ew in describing the energetic and entropic aspects of intermolecular interactions in liquid water.

Correlation of the vapor pressure isotope effect with molecular force fields in the liquid state

International Nuclear Information System (INIS)

Pollin, J.S.; Ishida, T.

1976-07-01

The present work is concerned with the development and application of a new model for condensed phase interactions with which the vapor pressure isotope effect (vpie) may be related to molecular forces and structure. The model considers the condensed phase as being represented by a cluster of regularly arranged molecules consisting of a central molecule and a variable number of molecules in the first coordination shell. The methods of normal coordinate analysis are used to determine the modes of vibration of the condensed phase cluster from which, in turn, the isotopic reduced partition function can be calculated. Using the medium cluster model, the observed vpie for a series of methane isotopes has been successfully reproduced with better agreement with experiment than has been possible using the simple cell model. We conclude, however, that insofar as the medium cluster model provides a reasonable picture of the liquid state, the vpie is not sufficiently sensitive to molecular orientation to permit an experimental determination of intermolecular configuration in the condensed phase through measurement of isotopic pressure ratios. The virtual independence of vapor pressure isotope effects on molecular orientation at large cluster sizes is a demonstration of the general acceptability of the cell model assumptions for vpie calculations

An Integrated Approach to Introducing Biofuels, Flash Point, and Vapor Pressure Concepts into an Introductory College Chemistry Lab

Science.gov (United States)

Hoffman, Adam R.; Britton, Stephanie L.; Cadwell, Katie D.; Walz, Kenneth A.

2011-01-01

Students explore the fundamental chemical concepts of vapor pressure and flash point in a real-world technical context, while gaining insight into the contemporary societal issue of biofuels. Lab activities were developed using a closed-cup instrument to measure the flash point of various biodiesel samples. Pre- and post-tests revealed that the…

The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques

Science.gov (United States)

Fahey, D. W.; Gao, R.-S.; Möhler, O.; Saathoff, H.; Schiller, C.; Ebert, V.; Krämer, M.; Peter, T.; Amarouche, N.; Avallone, L. M.; Bauer, R.; Bozóki, Z.; Christensen, L. E.; Davis, S. M.; Durry, G.; Dyroff, C.; Herman, R. L.; Hunsmann, S.; Khaykin, S. M.; Mackrodt, P.; Meyer, J.; Smith, J. B.; Spelten, N.; Troy, R. F.; Vömel, H.; Wagner, S.; Wienhold, F. G.

2014-09-01

The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques was conducted at the aerosol and cloud simulation chamber AIDA (Aerosol Interaction and Dynamics in the Atmosphere) at the Karlsruhe Institute of Technology, Germany, in October 2007. The overall objective was to intercompare state-of-the-art and prototype atmospheric hygrometers with each other and with independent humidity standards under controlled conditions. This activity was conducted as a blind intercomparison with coordination by selected referees. The effort was motivated by persistent discrepancies found in atmospheric measurements involving multiple instruments operating on research aircraft and balloon platforms, particularly in the upper troposphere and lower stratosphere, where water vapor reaches its lowest atmospheric values (less than 10 ppm). With the AIDA chamber volume of 84 m3, multiple instruments analyzed air with a common water vapor mixing ratio, by extracting air into instrument flow systems, by locating instruments inside the chamber, or by sampling the chamber volume optically. The intercomparison was successfully conducted over 10 days during which pressure, temperature, and mixing ratio were systematically varied (50 to 500 hPa, 185 to 243 K, and 0.3 to 152 ppm). In the absence of an accepted reference instrument, the absolute accuracy of the instruments was not established. To evaluate the intercomparison, the reference value was taken to be the ensemble mean of a core subset of the measurements. For these core instruments, the agreement between 10 and 150 ppm of water vapor is considered good with variation about the reference value of about ±10% (±1σ). In the region of most interest between 1 and 10 ppm, the core subset agreement is fair with variation about the reference value of ±20% (±1σ). The upper limit of precision was also derived for each instrument from the reported data. The implication for atmospheric measurements is that the

Relationship between the evaporation rate and vapor pressure of moderately and highly volatile chemicals.

Science.gov (United States)

van Wesenbeeck, Ian; Driver, Jeffrey; Ross, John

2008-04-01

Volatilization of chemicals can be an important form of dissipation in the environment. Rates of evaporative losses from plant and soil surfaces are useful for estimating the potential for food-related dietary residues and operator and bystander exposure, and can be used as source functions for screening models that predict off-site movement of volatile materials. A regression of evaporation on vapor pressure from three datasets containing 82 pesticidal active ingredients and co-formulants, ranging in vapor pressure from 0.0001 to >30,000 Pa was developed for this purpose with a regression correlation coefficient of 0.98.

Validation of Aura Microwave Limb Sounder stratospheric water vapor measurements by the NOAA frost point hygrometer.

Science.gov (United States)

Hurst, Dale F; Lambert, Alyn; Read, William G; Davis, Sean M; Rosenlof, Karen H; Hall, Emrys G; Jordan, Allen F; Oltmans, Samuel J

2014-02-16

Differences between stratospheric water vapor measurements by NOAA frost point hygrometers (FPHs) and the Aura Microwave Limb Sounder (MLS) are evaluated for the period August 2004 through December 2012 at Boulder, Colorado, Hilo, Hawaii, and Lauder, New Zealand. Two groups of MLS profiles coincident with the FPH soundings at each site are identified using unique sets of spatiotemporal criteria. Before evaluating the differences between coincident FPH and MLS profiles, each FPH profile is convolved with the MLS averaging kernels for eight pressure levels from 100 to 26 hPa (~16 to 25 km) to reduce its vertical resolution to that of the MLS water vapor retrievals. The mean FPH - MLS differences at every pressure level (100 to 26 hPa) are well within the combined measurement uncertainties of the two instruments. However, the mean differences at 100 and 83 hPa are statistically significant and negative, ranging from -0.46 ± 0.22 ppmv (-10.3 ± 4.8%) to -0.10 ± 0.05 ppmv (-2.2 ± 1.2%). Mean differences at the six pressure levels from 68 to 26 hPa are on average 0.8% (0.04 ppmv), and only a few are statistically significant. The FPH - MLS differences at each site are examined for temporal trends using weighted linear regression analyses. The vast majority of trends determined here are not statistically significant, and most are smaller than the minimum trends detectable in this analysis. Except at 100 and 83 hPa, the average agreement between MLS retrievals and FPH measurements of stratospheric water vapor is better than 1%.

Investigation of the vapor pressure p of zinc bromide or zinc chloride solutions with methanol by static method

International Nuclear Information System (INIS)

Safarov, Javid T.

2006-01-01

Vapor pressures p of ZnBr 2 + CH 3 OH and ZnCl 2 + CH 3 OH solutions at T (298.15 to 323.15) K were measured, activity of solvent a s and osmotic φ coefficients have been evaluated. The experiments were carried out for the ZnBr 2 + CH 3 OH solutions in the molality range m = (0.19972 to 11.05142) mol . kg -1 and for the ZnCl 2 + CH 3 OH solutions in the molality range m (0.42094 to 8.25534) mol . kg -1 . The Antoine equation for the empirical description of the experimental vapor pressure results and the Pitzer-Mayorga model with inclusion of ionic strength dependence of the third virial coefficient for the description of calculated osmotic coefficients were used. The parameters of Pitzer-Mayorga model were used for evaluation of activity coefficients

Pressure intelligent control strategy of Waste heat recovery system of converter vapors

Science.gov (United States)

Feng, Xugang; Wu, Zhiwei; Zhang, Jiayan; Qian, Hong

2013-01-01

The converter gas evaporative cooling system is mainly used for absorbing heat in the high temperature exhaust gas which produced by the oxygen blowing reaction. Vaporization cooling steam pressure control system of converter is a nonlinear, time-varying, lagging behind, close coupling of multivariable control object. This article based on the analysis of converter operation characteristics of evaporation cooling system, of vaporization in a production run of pipe pressure variation and disturbance factors.For the dynamic characteristics of the controlled objects,we have improved the conventional PID control scheme.In Oxygen blowing process, we make intelligent control by using fuzzy-PID cascade control method and adjusting the Lance,that it can realize the optimization of the boiler steam pressure control.By design simulation, results show that the design has a good control not only ensures drum steam pressure in the context of security, enabling efficient conversion of waste heat.And the converter of 1800 flue gas through pipes and cool and dust removal also can be cooled to about 800. Therefore the converter haze evaporative cooling system has achieved to the converter haze temperature decrease effect and enhanced to the coal gas returns-ratio.

Experimental study on vapor explosion induced by pressure pulse in coarse mixing of hot molten metal and water

International Nuclear Information System (INIS)

Inoue, A.; Tobita, Y.; Aritomi, M.; Takahashi, M.; Matsuzaki, M.

2004-01-01

An experimental study was done to investigate characteristics of metal-water interaction, when a mount of hot liquid metal is injected into the water. The test section is a vertical shock tube of 60mm in inner diameter and 1200mm in length. A special injector which is designed to inject hot metal of controlled volume and flow rate is attached at the top of the tube. When the hot metal is injected in the water and comes down at a position of the test vessel, a trigger pressure pulse is generated at the bottom of the test tube. Local transient pressures along the tube are measured by piezo pressure transducers. The following items were investigated in the experiment; 1) The criteria to cause a vapor explosion, 2) Transient behaviors and propagation characteristics of pressure wave in the mixing region. 3) Effects of triggering pulse, injection temperature and mass of hot molten metal on the peak pressure. The probability of the vapor explosion jumped when the interface temperature at the molten metal-water direct contact is higher than the homogeneous nucleation temperature of water and the triggering pulse becomes larger than 0.9MPa. Two types of the pressure propagation modes are observed, one is the detonative mode with a sharp rise and other is usual pressure mode with a mild rise. (author)

Vapor-liquid Phase Equilibria for CO2+Tertpentanol Binary System at Elevated Pressures

Institute of Scientific and Technical Information of China (English)

WANG Lin; LUO Jian-cheng; YANG Hao; CHEN Kai-xun

2011-01-01

Vapor-liquid phase equilibrium data of tertpentanol in carbon dioxide were measured at temperatures of 313.4,323.4,333.5 and 343.5 K and in the pressure range of 4.56-11.44 MPa.The phase equilibium apparatus used in the work was a variable-volume high-pressure cell.The experimental data were reasonably correlated with Peng-Robinson equation of state(PR-EOS) together with van der Waals-2 two-parameter mixing rules.Henry's Law constants and partial molar volumes of CO2 at infinite dilution were estimated with Krichevsky-Kasarnovsky equation,and Henry's Law constants increase with increasing temperature,however,partial molar volumes of CO2 at infinite dilution are negative whose magnitudes decrease with temperature.Partial molar volumes of CO2 and tertpentanol in liquid phase at equilibrium were calculated.

Accurate Laser Measurements of the Water Vapor Self-Continuum Absorption in Four Near Infrared Atmospheric Windows. a Test of the MT_CKD Model.

Science.gov (United States)

Campargue, Alain; Kassi, Samir; Mondelain, Didier; Romanini, Daniele; Lechevallier, Loïc; Vasilchenko, Semyon

2017-06-01

The semi empirical MT_CKD model of the absorption continuum of water vapor is widely used in atmospheric radiative transfer codes of the atmosphere of Earth and exoplanets but lacks of experimental validation in the atmospheric windows. Recent laboratory measurements by Fourier transform Spectroscopy have led to self-continuum cross-sections much larger than the MT_CKD values in the near infrared transparency windows. In the present work, we report on accurate water vapor absorption continuum measurements by Cavity Ring Down Spectroscopy (CRDS) and Optical-Feedback-Cavity Enhanced Laser Spectroscopy (OF-CEAS) at selected spectral points of the transparency windows centered around 4.0, 2.1 and 1.25 μm. The temperature dependence of the absorption continuum at 4.38 μm and 3.32 μm is measured in the 23-39 °C range. The self-continuum water vapor absorption is derived either from the baseline variation of spectra recorded for a series of pressure values over a small spectral interval or from baseline monitoring at fixed laser frequency, during pressure ramps. In order to avoid possible bias approaching the water saturation pressure, the maximum pressure value was limited to about 16 Torr, corresponding to a 75% humidity rate. After subtraction of the local water monomer lines contribution, self-continuum cross-sections, C_{S}, were determined with a few % accuracy from the pressure squared dependence of the spectra base line level. Together with our previous CRDS and OF-CEAS measurements in the 2.1 and 1.6 μm windows, the derived water vapor self-continuum provides a unique set of water vapor self-continuum cross-sections for a test of the MT_CKD model in four transparency windows. Although showing some important deviations of the absolute values (up to a factor of 4 at the center of the 2.1 μm window), our accurate measurements validate the overall frequency dependence of the MT_CKD2.8 model.

Growth of aligned ZnO nanowires via modified atmospheric pressure chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yuping; Li, Chengchen [Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China); Chen, Mingming, E-mail: andychain@live.cn [Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China); Yu, Xiao; Chang, Yunwei [Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China); Chen, Anqi [State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics & Information Technology, Sun Yat-Sen University, Guangzhou Higher Education Mega Center (University Town), Guangzhou, 510006 (China); Zhu, Hai, E-mail: zhuhai5@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics & Information Technology, Sun Yat-Sen University, Guangzhou Higher Education Mega Center (University Town), Guangzhou, 510006 (China); Tang, Zikang, E-mail: zktang@umac.mo [State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics & Information Technology, Sun Yat-Sen University, Guangzhou Higher Education Mega Center (University Town), Guangzhou, 510006 (China); The Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau (China)

2016-12-09

In this work, we report the growth of high-quality aligned ZnO nanowires via a facile atmospheric pressure chemical vapor deposition (CVD) method. The CVD reactor chamber used was more complicated than a conventional one due to the quartz boats loaded with sources (ZnO/C) and substrates being inserted into a semi-open quartz tube, and then placed inside the CVD reactor. The semi-open quartz tube played a very important role in growing the ZnO nanowires, and demonstrated that the transportation properties of Zn and O vapor differ from those in the conventional CVD reactor chamber. Aligned ZnO nanowires were successfully obtained, though they were only found at substrates located upstream. The very high crystalline quality of the obtained ZnO nanowires was demonstrated by high-resolution transmission electron microscopy and room temperature photoluminescence investigations. Such ZnO nanowires with high crystalline quality may provide opportunities for the fabrication of ZnO-based nano-devices in future. - Highlights: • High-quality aligned ZnO nanowires were obtained via modified chemical vapor deposition under atmospheric pressure. • The semi-open quartz tube plays very important roles in growing ZnO nanowires. • The transportation properties of Zn and O vapor differ from those in the conventional CVD reactor chamber.

Growth of aligned ZnO nanowires via modified atmospheric pressure chemical vapor deposition

International Nuclear Information System (INIS)

Zhao, Yuping; Li, Chengchen; Chen, Mingming; Yu, Xiao; Chang, Yunwei; Chen, Anqi; Zhu, Hai; Tang, Zikang

2016-01-01

In this work, we report the growth of high-quality aligned ZnO nanowires via a facile atmospheric pressure chemical vapor deposition (CVD) method. The CVD reactor chamber used was more complicated than a conventional one due to the quartz boats loaded with sources (ZnO/C) and substrates being inserted into a semi-open quartz tube, and then placed inside the CVD reactor. The semi-open quartz tube played a very important role in growing the ZnO nanowires, and demonstrated that the transportation properties of Zn and O vapor differ from those in the conventional CVD reactor chamber. Aligned ZnO nanowires were successfully obtained, though they were only found at substrates located upstream. The very high crystalline quality of the obtained ZnO nanowires was demonstrated by high-resolution transmission electron microscopy and room temperature photoluminescence investigations. Such ZnO nanowires with high crystalline quality may provide opportunities for the fabrication of ZnO-based nano-devices in future. - Highlights: • High-quality aligned ZnO nanowires were obtained via modified chemical vapor deposition under atmospheric pressure. • The semi-open quartz tube plays very important roles in growing ZnO nanowires. • The transportation properties of Zn and O vapor differ from those in the conventional CVD reactor chamber.

Vapor pressures and isopiestic molalities of concentrated CaCl{sub 2}(aq), CaBr{sub 2}(aq), and NaCl(aq) to T = 523 K

Energy Technology Data Exchange (ETDEWEB)

Gruszkiewicz, Miroslaw S. [Oak Ridge National Laboratory, Chemical Sciences Division, P.O. Box 2008, Building 4500S MS-6110, Oak Ridge, TN 37831-6110 (United States)]. E-mail: gruszkiewicz@ornl.gov; Simonson, John M. [Oak Ridge National Laboratory, Chemical Sciences Division, P.O. Box 2008, Building 4500S MS-6110, Oak Ridge, TN 37831-6110 (United States)]. E-mail: simonsonjm@ornl.gov

2005-09-15

The Oak Ridge National Laboratory high-temperature isopiestic apparatus was outfitted with precise pressure gauges to allow for direct vapor pressure measurements. Vapor pressures over concentrated solutions of CaCl{sub 2}(aq), and CaBr{sub 2}(aq) were measured at temperatures between (380.15 and 523.15) K in the range of water activities between 0.2 and 0.85. Isopiestic molalities were used to determine osmotic coefficients at the conditions where NaCl reference standard solutions remained undersaturated. The main goal of this work was to improve the accuracy of isopiestic comparisons based on the calcium chloride reference standard. Osmotic coefficients for CaCl{sub 2}(aq) and CaBr{sub 2}(aq) calculated from both isopiestic and direct vapor pressure results were combined with the literature data and used to build general thermodynamic models based on a variant of extended Pitzer ion-interaction equations and valid at the saturation pressure of water. While these empirical models approach the accuracy of the experimental data in a wider range of concentrations and temperatures than any previously published equations, considerable amounts of accurate data and a substantial effort are required in order to obtain a satisfactory representation using power series-based virial equations. The effect of experimental uncertainties on the accuracy of the direct vapor pressure results is discussed, including in particular the error caused by the presence in the apparatus of a small amount of CO{sub 2}. The substantial decrease of the solubility product of CaCO{sub 3} in concentrated chloride solutions at temperatures above 423 K is a serious defect of calcium chloride as a water activity reference standard.

Experimental study on the performance of the vapor injection refrigeration system with an economizer for intermediate pressures

Science.gov (United States)

Moon, Chang-Uk; Choi, Kwang-Hwan; Yoon, Jung-In; Kim, Young-Bok; Son, Chang-Hyo; Ha, Soo-Jung; Jeon, Min-Ju; An, Sang-Young; Lee, Joon-Hyuk

2018-04-01

In this study, to investigate the performance characteristics of vapor injection refrigeration system with an economizer at an intermediate pressure, the vapor injection refrigeration system was analyzed under various experiment conditions. As a result, the optimum design data of the vapor injection refrigeration system with an economizer were obtained. The findings from this study can be summarized as follows. The mass flow rate through the compressor increases with intermediate pressure. The compression power input showed an increasing trend under all the test conditions. The evaporation capacity increased and then decreased at the intermediate pressure, and as such, it became maximum at the given intermediate pressure. The increased mass flow rate of the by-passed refrigerant enhanced the evaporation capacity at the low medium pressure range, but the increased saturation temperature limited the subcooling degree of the liquid refrigerant after the application of the economizer when the intermediate pressure kept rising, and degenerated the evaporation capacity. The coefficient of performance (COP) increased and then decreased with respect to the intermediate pressures under all the experiment conditions. Nevertheless, there was an optimum intermediate pressure for the maximum COP under each experiment condition. Therefore, the optimum intermediate pressure in this study was found at -99.08 kPa, which is the theoretical standard medium pressure under all the test conditions.

The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

Energy Technology Data Exchange (ETDEWEB)

Ruhrmann, C.; Hoebing, T.; Bergner, A.; Groeger, S.; Awakowicz, P.; Mentel, J. [Electrical Engineering and Plasma Technology, Ruhr University Bochum, D-44780 Bochum (Germany); Denissen, C.; Suijker, J. [Philips Lighting, Category Professional Lamps, P.O. Box 80020, NL-5600JM Eindhoven (Netherlands)

2015-08-07

The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emitter effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.

DETERMINATION OF SATURATION VAPOR PRESSURE OF LOW VOLATILE SUBSTANCES THROUGH THE STUDY OF EVAPORATION RATE BY THERMOGRAVIMETRIC ANALYSIS

Directory of Open Access Journals (Sweden)

R. V. Ralys

2015-11-01

Full Text Available Subject of Study.Research of vapor pressure of low volatile substances is a complicated problem due to both direct experimental implementation complexity and, most significantly, the issues faced correctness of the analysis and processing of experimental data. That is why it is usually required engaging the reference substances (with vapor pressures well studied. The latter drastically reduces the effectiveness of the experimental methods used and narrows their applicability. The paper deals with an approach to the evaporation process description (sublimation of low volatile substances based on molecular kinetic description in view of diffusive and convection processes. The proposed approach relies on experimental thermogravimetricfindingsina wide range of temperatures, flow rates ofthe purge gas and time. Method. A new approach is based on the calculation of the vapor pressure and uses the data about the speed of evaporation by thermogravimetric analysis depending on the temperature, the flow rate of the purge gas, and the evaporation time. The basis for calculation is the diffusion-kinetic description of the process of evaporation (mass loss of the substance from the exposed surface. The method is applicable to determine the thermodynamic characteristics for both the evaporation (the equilibrium liquid - vapor and sublimation (the equilibrium solid - vapor. We proposed the appropriate method of the experiment and analysis of its data in order to find the saturated vapor pressure of individual substances of low volatility. Main Results. The method has been tested on substances with insufficiently reliable and complete study of the thermodynamic characteristics but, despite this, are often used (because of the other data limitations as reference ones. The vaporization process (liquid-vapor has been studied for di-n-butyl phthalate C16H22O4 at 323,15–443,15 К, and sublimation for benzoic acid C7H6O2at 303,15–183,15 К. Both processes have

Water vapor pressure over molten KH_2PO_4 and demonstration of water electrolysis at ∼300 °C

International Nuclear Information System (INIS)

Berg, R.W.; Nikiforov, A.V.; Petrushina, I.M.; Bjerrum, N.J.

2016-01-01

Highlights: • The vapor pressure over molten KH_2PO_4 was measured by Raman spectroscopy to be about 8 bars at ∼300 °C. • Raman spectroscopy shows that molten KH_2PO_4 under its own vapor pressure contains much dissolved water. • It is demonstrated spectroscopically that water electrolysis is possible in KH_2PO_4 electrolyte forming H_2 and O_2 at 300 °C. • Molten KH_2PO_4 is a possible electrolyte for water electrolysis. - Abstract: A new potentially high-efficiency electrolyte for water electrolysis: molten monobasic potassium phosphate, KH_2PO_4 or KDP has been investigated at temperatures ∼275–325 °C. At these temperatures, KH_2PO_4 was found to dissociate into H_2O gas in equilibrium with a melt mixture of KH_2PO_4−K_2H_2P_2O_7−KPO_3−H_2O. The water vapor pressure above the melt, when contained in a closed ampoule, was determined quantitatively vs. temperature by use of Raman spectroscopy with methane or hydrogen gas as an internal calibration standard, using newly established relative ratios of Raman scattering cross sections of water and methane or hydrogen to be 0.40 ± 0.02 or 1.2 ± 0.03. At equilibrium the vapor pressure was much lower than the vapor pressure above liquid water at the same temperature. Electrolysis was realized by passing current through closed ampoules (vacuum sealed quartz glass electrolysis cells with platinum electrodes and the electrolyte melt). The formation of mixtures of hydrogen and oxygen gases as well as the water vapor was detected by Raman spectroscopy. In this way it was demonstrated that water is present in the new electrolyte: molten KH_2PO_4 can be split by electrolysis via the reaction 2H_2O → 2H_2 + O_2 at temperatures ∼275–325 °C. At these temperatures, before the start of the electrolysis, the KH_2PO_4 melt gives off H_2O gas that pressurizes the cell according to the following dissociations: 2KH_2PO_4 ↔ K_2H_2P_2O_7 + H_2O ↔ 2KPO_3 + 2H_2O. The spectra show however that the water by

Saturated vapor pressure over molten mixtures of GaCl3 and alkali metal chlorides

International Nuclear Information System (INIS)

Salyulev, A.B.; Smolenskij, V.V.; Moskalenko, N.I.

2004-01-01

Volatilities of GaCl 3 and alkali metal chlorides over diluted (up to 3 mol %) solutions of GaCl 3 in LiCl, NaCl, KCl, RbCl, and CsCl were measured at 1100 K by dynamic and indirect static methods. Chemical composition of saturated vapor over the mixed melts was determined. Partial pressures of the components were calculated. Their values depend essentially on specific alkali metal cation and on concentration of GaCl 3 ; their variation permits altering parameters of GaCl 3 distillation from the salt melt in a wide range [ru

The Comparative Study on Vapor-Polymerization and Pressure-dependent Conductance Behavior in Polypyrrole-hybridized Membranes

Energy Technology Data Exchange (ETDEWEB)

Hanif, Zahid; Lee, Seyeong; Arsalani, Nasir; Geckeler, Kurt E.; Hong, Sukwon; Yoon, Myung-Han [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

2016-02-15

In this study, commercially available cellulose membranes were hybridized with conjugated polymer via vapor-phase polymerization using pyrrole and iron chloride as a monomer and oxidant, respectively. The iron (III) chloride layer dip-coated on the hydrophilic cell ulose surface oxidized the vaporized pyrrole monomer leading to the polypyrrole-cellulose hybrid membrane. The conductivity of hybrid membrane was optimized by varying the oxidant concentration and the monomer vapor exposure time. The various surface characterizations of polypyrrole-cellulose hybrid membrane show that the conductive polypyrrole layer was uniformly deposited onto the surface of cellulose fibrous networks unlike the polypyrrole-nylonhybrid membrane prepared in the similar way. The polypyrrole-incorporated cellulose networks exhibits steeper electrical conductance increase over the vertical pressure than its nylon counterpart. Our result suggests that the polypyrrole-cellulose hybrid membrane can be applicable for a disposable high-load pressure sensor.

The Comparative Study on Vapor-Polymerization and Pressure-dependent Conductance Behavior in Polypyrrole-hybridized Membranes

International Nuclear Information System (INIS)

Hanif, Zahid; Lee, Seyeong; Arsalani, Nasir; Geckeler, Kurt E.; Hong, Sukwon; Yoon, Myung-Han

2016-01-01

In this study, commercially available cellulose membranes were hybridized with conjugated polymer via vapor-phase polymerization using pyrrole and iron chloride as a monomer and oxidant, respectively. The iron (III) chloride layer dip-coated on the hydrophilic cell ulose surface oxidized the vaporized pyrrole monomer leading to the polypyrrole-cellulose hybrid membrane. The conductivity of hybrid membrane was optimized by varying the oxidant concentration and the monomer vapor exposure time. The various surface characterizations of polypyrrole-cellulose hybrid membrane show that the conductive polypyrrole layer was uniformly deposited onto the surface of cellulose fibrous networks unlike the polypyrrole-nylonhybrid membrane prepared in the similar way. The polypyrrole-incorporated cellulose networks exhibits steeper electrical conductance increase over the vertical pressure than its nylon counterpart. Our result suggests that the polypyrrole-cellulose hybrid membrane can be applicable for a disposable high-load pressure sensor.

Measurement of gas transport properties for chemical vapor infiltration

Energy Technology Data Exchange (ETDEWEB)

Starr, T.L.; Hablutzel, N. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

1996-12-01

In the chemical vapor infiltration (CVI) process for fabricating ceramic matrix composites (CMCs), transport of gas phase reactant into the fiber preform is a critical step. The transport can be driven by pressure or by concentration. This report describes methods for measuring this for CVI preforms and partially infiltrated composites. Results are presented for Nicalon fiber cloth layup preforms and composites, Nextel fiber braid preforms and composites, and a Nicalon fiber 3-D weave composite. The results are consistent with a percolating network model for gas transport in CVI preforms and composites. This model predicts inherent variability in local pore characteristics and transport properties, and therefore, in local densification during processing; this may lead to production of gastight composites.

Net vapor generation point in boiling flow of trichlorotrifluoroethane at high pressures

Science.gov (United States)

Dougall, R. S.; Lippert, T. E.

1973-01-01

The conditions at which the void in subcooled boiling starts to undergo a rapid increase were studied experimentally. The experiments were performed in a 12.7 x 9.5 mm rectangular channel. Heating was from a 3.2 mm wide strip embedded in one wall. The pressure ranged from 9.45 to 20.7 bar, mass velocity from 600 to 7000 kg/sq m sec, and subcooling from 16 to 67 C. Photographs were used to determine when detached bubbles first appeared in the bulk flow. Measurements of bubble layer thickness along the wall were also made. Results showed that the point of net vapor generation is close to the occurrence of fully-developed boiling.

Investigation of the vapor pressure p of zinc bromide or zinc chloride solutions with methanol by static method

Energy Technology Data Exchange (ETDEWEB)

Safarov, Javid T. [Heat and Refrigeration Techniques, Azerbaijan Technical University, H. Javid Avn. 25, AZ1073 Baku (Azerbaijan)]. E-mail: javids@azdata.net

2006-03-15

Vapor pressures p of ZnBr{sub 2} + CH{sub 3}OH and ZnCl{sub 2} + CH{sub 3}OH solutions at T (298.15 to 323.15) K were measured, activity of solvent a {sub s} and osmotic {phi} coefficients have been evaluated. The experiments were carried out for the ZnBr{sub 2} + CH{sub 3}OH solutions in the molality range m = (0.19972 to 11.05142) mol . kg{sup -1} and for the ZnCl{sub 2} + CH{sub 3}OH solutions in the molality range m (0.42094 to 8.25534) mol . kg{sup -1}. The Antoine equation for the empirical description of the experimental vapor pressure results and the Pitzer-Mayorga model with inclusion of ionic strength dependence of the third virial coefficient for the description of calculated osmotic coefficients were used. The parameters of Pitzer-Mayorga model were used for evaluation of activity coefficients.

Effect of superficial velocity on vaporization pressure drop with propane in horizontal circular tube

Science.gov (United States)

Novianto, S.; Pamitran, A. S.; Nasruddin, Alhamid, M. I.

2016-06-01

Due to its friendly effect on the environment, natural refrigerants could be the best alternative refrigerant to replace conventional refrigerants. The present study was devoted to the effect of superficial velocity on vaporization pressure drop with propane in a horizontal circular tube with an inner diameter of 7.6 mm. The experiments were conditioned with 4 to 10 °C for saturation temperature, 9 to 20 kW/m2 for heat flux, and 250 to 380 kg/m2s for mass flux. It is shown here that increased heat flux may result in increasing vapor superficial velocity, and then increasing pressure drop. The present experimental results were evaluated with some existing correlations of pressure drop. The best prediction was evaluated by Lockhart-Martinelli (1949) with MARD 25.7%. In order to observe the experimental flow pattern, the present results were also mapped on the Wang flow pattern map.

Comparisons between a gas-phase model of silane chemical vapor deposition and laser-diagnostic measurements

International Nuclear Information System (INIS)

Breiland, W.G.; Coltrin, M.E.; Ho, P.

1986-01-01

Theoretical modeling and experimental measurements have been used to study gas-phase chemistry in the chemical vapor deposition (CVD) of silicon from silane. Pulsed laser Raman spectroscopy was used to obtain temperature profiles and to obtain absolute density profiles of silane during deposition at atmospheric and 6-Torr total pressures for temperatures ranging from 500 to 800 0 C. Laser-excited fluorescence was used to obtain relative density profiles of Si 2 during deposition at 740 0 C in helium with 0-12 Torr added hydrogen. These measurements are compared to predictions from the theoretical model of Coltrin, Kee, and Miller. The predictions agree qualitatively with experiment. These studies indicate that fluid mechanics and gas-phase chemical kinetics are important considerations in understanding the chemical vapor deposition process

Recommended vapor pressures for aniline, nitromethane, 2-aminoethanol, and 1-methyl-2-pyrrolidone

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Fulem, Michal; Mahnel, T.; Červinka, C.

2015-01-01

Roč. 406, Nov (2015), 34-46 ISSN 0378-3812 Institutional support: RVO:68378271 Keywords : recommended vapor pressure equations * heat capacity * ideal - gas thermodynamic properties * aniline * nitromethane Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015

Beer Law Constants and Vapor Pressures of HgI2 over HgI2(s,l)

Science.gov (United States)

Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.

2002-01-01

Optical absorption spectra of the vapor phase over HgI2(s,l) were measured at sample temperatures between 349 and 610 K for wavelengths between 200 and 600 nm. The spectra show the samples sublimed congruently into HGI2 without any observed Hg or I2 absorption spectra. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were derived. From these constants the vapor pressure of HgI2, P, was found to be a function of temperature for the liquid and the solid beta-phases: ln P(atm) = -7700/T(K) + 12.462 (liquid phase) and ln P(atm) = -10150/T(K) + 17.026 (beta-phase). The expressions match the enthalpies of vaporization and sublimation of 15.30 and 20.17 kcal/mole respectively, for the liquid and the beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 kcal/mole, and the intersection of the two expressions gives a melting point of 537 K.

HIGH-PRESSURE VAPOR-LIQUID EQUILIBRIUM DATA FOR BINARY AND TERNARY SYSTEMS FORMED BY SUPERCRITICAL CO2, LIMONENE AND LINALOOL

Directory of Open Access Journals (Sweden)

MELO S. A. B. VIEIRA DE

1999-01-01

Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.

Isotope effects in the equilibrium and non-equilibrium vaporization of tritiated water and ice

International Nuclear Information System (INIS)

Baumgaertner, F.; Kim, M.-A.

1990-01-01

The vaporization isotope effect of the HTO/H 2 O system has been measured at various temperatures and pressures under equilibrium as well as non-equilibrium conditions. The isotope effect values measured in equilibrium sublimation or distillation are in good agreement with the theoretical values based on the harmonic oscillator model. In non-equilibrium vaporization at low temperatures ( 0 C), the isotope effect decreases rapidly with decreasing system pressure and becomes negligible when the system pressure is lowered more than one tenth of the equilibrium vapor pressure. At higher temperatures, the isotope effect decreases very slowly with decreasing system pressure. Discussion is extended for the application of the present results to the study of biological enrichment of tritium. (author)

Muonium formation and the 'missing fraction' in vapors

International Nuclear Information System (INIS)

Fleming, D.G.; Arseneau, D.J.; Garner, D.M.; Senba, M.; Mikula, R.J.

1983-06-01

The vapor phase fractional polarizations of positive muons thermalizing as the muonium atom (Psub(M)) and in diamagnetic environments (Psub(D)) has been measured in H 2 O, CH 3 OH, C 6 H 14 , C 6 H 12 , CCl 4 , CHCl 3 , CH 2 Cl 2 and TMS, in order to compare with the corresponding fractions measured in the condensed phases. There is a marked contrast in every case, with the vapor phase results being largely understandable in terms of a charge exchange/hot atom model. Unlike the situation in the corresponding liquids, there is no permanent lost fraction in the vapor phase in the limit of even moderately high pressures (approximately 1 atm); at lower pressures, depolarization is due to hyperfine mixing and is believed to be well understood. For vapor phase CH 3 OH, C 6 H 14 , C 6 H 12 , and TMS the relative fractions are found to be pressure dependent, suggesting the importance of termolecular hot atom (or ion) reactions in the slowing-down process. For vapor phase H 2 O and the chloromethanes, the relative fractions are pressure independent. For CCl 4 , Psub(M) = Psub(D) approximately 0.5 in the vapor phase vs. Psub(D) = 1.0 in the liquid phase; fast thermal reactions of Mu likely contribute significantly to this difference in the liquid phase. For H 2 O, Psub(M) approximately 0.9 and Psub(D) approximately 0.1 in the vapor phase vs. Psub(D) approximately 0.6 and Psub(M) approximately 0.2 in the liquid phase. Water appears to be the one unequivocal case where the basic charge exchange/hot atom model is inappropriate in the condensed phase, suggesting, therefore, that radiation-induced 'spur' effects play a major role

Studies on micro-structures at vapor-liquid interfaces of film boiling on hot liquid surface at arriving of a shock pressure

Energy Technology Data Exchange (ETDEWEB)

Inoue, Akira; Lee, S. [Tokyo Inst. of Tech. (Japan)

1998-01-01

In vapor explosions, a pressure wave (shock wave) plays a fundamental role in the generation, propagation and escalation of the explosion. Transient volume change by rapid heat flow from a high temperature liquid to a low temperature volatile one and phase change generate micro-scale flow and the pressure wave. One of key issues for the vapor explosion is to make clear the mechanism to support the explosive energy release from hot drop to cold liquid. According to our observations by an Image Converter Camera, growth rate of vapor film around a hot tin drop became several times higher than that around a hot Platinum tube at the same conditions when a pressure pulse collapsed the film. The thermally induced fragmentation was followed by the explosive growth rate of the hot drop. In the previous report, we have proposed that the interface instability and fragmentation model in which the fine Taylor instability of vapor-liquid interface at the collapsing and re-growth phase of vapor film and the instability induced by the high pressure spots at the drop surface were assumed. In this study, the behavior of the vapor-liquid interface region at arrival of a pressure pulse was investigated by the CIPRIS code which is able to simulate dynamics of transient multi-phase interface regions. It is compared with the observation results. Through detailed investigations of these results, the mechanisms of the thermal fragmentation of single drop are discussed. (J.P.N.)

In-reactor oxidation of zircaloy-4 under low water vapor pressures

Science.gov (United States)

Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

2015-01-01

Complementary in- and ex-reactor oxidation tests have been performed to evaluate the oxidation and hydrogen absorption performance of Zircaloy-4 (Zr-4) under relatively low partial pressures (300 and 1000 Pa) of water vapor at specified test temperatures (330 and 370 °C). Data from these tests will be used to support the fabrication of components intended for isotope-producing targets and provide information regarding the temperature and pressure dependence of oxidation and hydrogen absorption of Zr-4 over the specified range of test conditions. Comparisons between in- and ex-reactor test results were performed to evaluate the influence of irradiation.

In-reactor oxidation of zircaloy-4 under low water vapor pressures

International Nuclear Information System (INIS)

Luscher, Walter G.; Senor, David J.; Clayton, Kevin K.; Longhurst, Glen R.

2015-01-01

Complementary in- and ex-reactor oxidation tests have been performed to evaluate the oxidation and hydrogen absorption performance of Zircaloy-4 (Zr-4) under relatively low partial pressures (300 and 1000 Pa) of water vapor at specified test temperatures (330 and 370 ℃). Data from these tests will be used to support the fabrication of components intended for isotope-producing targets and provide information regarding the temperature and pressure dependence of oxidation and hydrogen absorption of Zr- 4 over the specified range of test conditions. Comparisons between in- and ex-reactor test results were performed to evaluate the influence of irradiation.

VLE measurements using a static cell vapor phase manual sampling method accompanied with an empirical data consistency test

International Nuclear Information System (INIS)

Freitag, Joerg; Kosuge, Hitoshi; Schmelzer, Juergen P.; Kato, Satoru

2015-01-01

Highlights: • We use a new, simple static cell vapor phase manual sampling method (SCVMS) for VLE (x, y, T) measurement. • The method is applied to non-azeotropic, asymmetric and two-liquid phase forming azeotropic binaries. • The method is approved by a data consistency test, i.e., a plot of the polarity exclusion factor vs. pressure. • The consistency test reveals that with the new SCVMS method accurate VLE near ambient temperature can be measured. • Moreover, the consistency test approves that the effect of air in the SCVMS system is negligible. - Abstract: A new static cell vapor phase manual sampling (SCVMS) method is used for the simple measurement of constant temperature x, y (vapor + liquid) equilibria (VLE). The method was applied to the VLE measurements of the (methanol + water) binary at T/K = (283.2, 298.2, 308.2 and 322.9), asymmetric (acetone + 1-butanol) binary at T/K = (283.2, 295.2, 308.2 and 324.2) and two-liquid phase forming azeotropic (water + 1-butanol) binary at T/K = (283.2 and 298.2). The accuracy of the experimental data was approved by a data consistency test, that is, an empirical plot of the polarity exclusion factor, β, vs. the system pressure, P. The SCVMS data are accurate, because the VLE data converge to the same lnβ vs. lnP straight line determined from conventional distillation-still method and a headspace gas chromatography method

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry.

Science.gov (United States)

Holloway, Paul H; Pritchard, David G

2017-08-01

The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber. © The Author 2017. Published by Oxford University Press on behalf of Poultry Science Association.

Rapid Chemical Vapor Infiltration of Silicon Carbide Minicomposites at Atmospheric Pressure.

Science.gov (United States)

Petroski, Kenneth; Poges, Shannon; Monteleone, Chris; Grady, Joseph; Bhatt, Ram; Suib, Steven L

2018-02-07

The chemical vapor infiltration technique is one of the most popular for the fabrication of the matrix portion of a ceramic matrix composite. This work focuses on tailoring an atmospheric pressure deposition of silicon carbide onto carbon fiber tows using the methyltrichlorosilane (CH 3 SiCl 3 ) and H 2 deposition system at atmospheric pressure to create minicomposites faster than low pressure systems. Adjustment of the flow rate of H 2 bubbled through CH 3 SiCl 3 will improve the uniformity of the deposition as well as infiltrate the substrate more completely as the flow rate is decreased. Low pressure depositions conducted at 50 Torr deposit SiC at a rate of approximately 200 nm*h -1 , while the atmospheric pressure system presented has a deposition rate ranging from 750 nm*h -1 to 3.88 μm*h -1 . The minicomposites fabricated in this study had approximate total porosities of 3 and 6% for 10 and 25 SCCM infiltrations, respectively.

Temperature sensitivity of differential absorption lidar measurements of water vapor in the 720-nm region

Science.gov (United States)

Browell, Edward V.; Ismail, Syed; Grossmann, Benoist E.

1991-01-01

Recently measured properties of water vapor (H2O) absorption lines have been used in calculations to evalute the temperature sensitivity of differential absorption lidar (Dial) H2O measurements. This paper estimates the temperature sensitivity of H2O lines in the 717-733-nm region for both H2O mixing ratio and number density measurements, and discusses the influence of the H2O line ground state energies E-double-prime, the H2O absorption linewidths, the linewidth temperature dependence parameter, and the atmospheric temperature and pressure variations with altitude and location on the temperature sensitivity calculations. Line parameters and temperature sensitivity calculations for 67 H2O lines in the 720-nm band are given which can be directly used in field experiments. Water vapor lines with E-double-prime values in the 100-300/cm range were found to be optimum for Dial measurements of H2O number densities, while E-double-prime values in the 250-500/cm range were found to be optimum for H2O mixing ratio measurements.

Recommended reference materials for realization of physicochemical properties pressure-volume-temperature relationships

CERN Document Server

Herington, E F G

1977-01-01

Recommended Reference Materials for Realization of Physicochemical Properties presents recommendations of reference materials for use in measurements involving physicochemical properties, namely, vapor pressure; liquid-vapor critical temperature and critical pressure; orthobaric volumes of liquid and vapor; pressure-volume-temperature properties of the unsaturated vapor or gas; and pressure-volume-temperature properties of the compressed liquid. This monograph focuses on reference materials for vapor pressures at temperatures up to 770 K, as well as critical temperatures and critical pressures

Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions

KAUST Repository

Sharma, Ashish; Levko, Dmitry; Raja, Laxminarayan L; Cha, Min

2016-01-01

We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble

Mass Spectrometric Identification of Si-O-H(g) Species from the Reaction of Silica with Water Vapor at Atmospheric Pressure

Science.gov (United States)

Opila, Elizabeth J.; Fox, Dennis S.; Jacobson, Nathan S.

1997-01-01

A high-pressure sampling mass spectrometer was used to detect the volatile species formed from SiO2 at temperatures between 1200C and 1400C in a flowing water vapor/oxygen gas mixture at 1 bar total pressure. The primary vapor species identified was Si(OH)4. The fragment ion Si(OH)3+,' was observed in quantities 3 to 5 times larger than the parent ion Si(OH)4+. The Si(OH)3+ intensity was found to have a small temperature dependence and to increase with the water vapor partial pressure as expected. In addition, SiO(OH)+ believed to be a fragment of SiO(OH)2, was observed. These mass spectral results were compared to the behavior of silicon halides.

Auxiliary Electrodes for Chromium Vapor Sensors

Energy Technology Data Exchange (ETDEWEB)

Fergus, Jeffrey; Shahzad, Moaiz; Britt, Tommy

2018-05-15

Measurement of chromia-containing vapors in solid oxide fuel cell systems is useful for monitoring and addressing cell degradation caused by oxidation of the chomia scale formed on alloys for interconnects and balance-of-plant components. One approach to measuring chromium is to use a solid electrolyte with an auxiliary electrode that relates the partial pressure of the chromium containing species to the mobile species in the electrolyte. One example is YCrO3 which can equilibrate with the chromium containing vapor and yttrium in yttria stabilized zirconia to establish an oxygen activity. Another is Na2CrO4 which can equilibrate with the chromium-containing vapor to establish a sodium activity.

Water vapor-nitrogen absorption at CO2 laser frequencies

Science.gov (United States)

Peterson, J. C.; Thomas, M. E.; Nordstrom, R. J.; Damon, E. K.; Long, R. K.

1979-01-01

The paper reports the results of a series of pressure-broadened water vapor absorption measurements at 27 CO2 laser frequencies between 935 and 1082 kaysers. Both multiple traversal cell and optoacoustic (spectrophone) techniques were utilized together with an electronically stabilized CW CO2 laser. Comparison of the results obtained by these two methods shows remarkable agreement, indicating a precision which has not been previously achieved in pressure-broadened studies of water vapor. The data of 10.59 microns substantiate the existence of the large (greater than 200) self-broadening coefficients determined in an earlier study by McCoy. In this work, the case of water vapor in N2 at a total pressure of 1 atm has been treated.

Effect of Furnish on Temperature and Vapor Pressure Behavior in the Center of Mat Panels during Hot Pressing

Directory of Open Access Journals (Sweden)

Muhammad Navis Rofii

2014-07-01

Full Text Available Particleboard achieves its overall performance characteristics during hot pressing process. As this process is influenced by several factors, particularly temperature and pressure, it is very important to understand the behavior of both. This study investigates the effects of furnish materials on temperature and vapor pressure behavior inside particleboard mat panels during hot pressing. Strand type particles from hinoki and ring-flaker recycled wood particles were used as furnish for laboratory-scale particleboard panels with a target density of 0.76 g/cm³. Mat panels with a moisture content of about 10% were hot pressed at a platen temperature of 180°C and an initial pressure of 3 MPa until the mat center reached the same temperature as the platen. A press monitoring device (PressMAN Lite was used for detecting the temperature and vapor pressure change in the center of the mat panels. The study showed that the furnish type affected the temperature and vapor behavior inside the mat panels. Particleboard made of hinoki strand resulted in a longer plateau time, a higher plateau temperature and a higher gas pressure generated during hot pressing than those of ring-flaker recycled wood particles. Mixed board resulted in values between those of the two other furnish materials.

Ionic association and solvation of the ionic liquid 1-hexyl-3-methylimidazolium chloride in molecular solvents revealed by vapor pressure osmometry, conductometry, volumetry, and acoustic measurements.

Science.gov (United States)

Sadeghi, Rahmat; Ebrahimi, Nosaibah

2011-11-17

A systematic study of osmotic coefficient, conductivity, volumetric and acoustic properties of solutions of ionic liquid 1-hexyl-3-methylimidazolium chloride ([C(6)mim][Cl]) in various molecular solvents has been made at different temperatures in order to study of ionic association and solvation behavior of [C(6)mim][Cl] in different solutions. Precise measurements on electrical conductances of solutions of [C(6)mim][Cl] in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and acetonitrile at 293.15, 298.15, and 303.15 K are reported and analyzed with Barthel's low-concentration chemical model (lcCM) to obtain the limiting molar conductivities and association constants of this ionic liquid in the investigated solvents. Strong ion pairing was found for the ionic liquid in 2-propanol, 1-butanol, and 1-propanol, whereas ion association in acetonitrile, methanol and ethanol is rather weak and in water the ionic liquid is fully dissociated. In the second part of this work, the apparent molar volumes and isentropic compressibilities of [C(6)mim][Cl] in water, methanol, ethanol, acetonitrile, 1-propanol, 2-propanol, and 1-butanol are obtained at the 288.15-313.15 K temperature range at 5 K intervals at atmospheric pressure from the precise measurements of density and sound velocity. The infinite dilution apparent molar volume and isentropic compressibility values of the free ions and ion pairs of [C(6)mim][Cl] in the investigated solvents as well as the excess molar volume of the investigated solutions are determined and their variations with temperature and type of solvents are also studied. Finally, the experimental measurements of osmotic coefficient at 318.15 K for binary solutions of [C(6)mim][Cl] in water, methanol, ethanol, 2-propanol, and acetonitrile are taken using the vapor pressure osmometry (VPO) method and from which the values of the solvent activity, vapor pressure, activity coefficients, and Gibbs free energies are calculated. The results are

Two decades of water vapor measurements with the FISH fluorescence hygrometer: a review

Directory of Open Access Journals (Sweden)

J. Meyer

2015-07-01

Full Text Available For almost two decades, the airborne Fast In-situ Stratospheric Hygrometer (FISH has stood for accurate and precise measurements of total water mixing ratios (WMR, gas phase + evaporated ice in the upper troposphere and lower stratosphere (UT/LS. Here, we present a comprehensive review of the measurement technique (Lyman-α photofragment fluorescence, calibration procedure, accuracy and reliability of FISH. Crucial for FISH measurement quality is the regular calibration to a water vapor reference, namely the commercial frost-point hygrometer DP30. In the frame of this work this frost-point hygrometer is compared to German and British traceable metrological water standards and its accuracy is found to be 2–4 %. Overall, in the range from 4 to 1000 ppmv, the total accuracy of FISH was found to be 6–8 %, as stated in previous publications. For lower mixing ratios down to 1 ppmv, the uncertainty reaches a lower limit of 0.3 ppmv. For specific, non-atmospheric conditions, as set in experiments at the AIDA chamber – namely mixing ratios below 10 and above 100 ppmv in combination with high- and low-pressure conditions – the need to apply a modified FISH calibration evaluation has been identified. The new evaluation improves the agreement of FISH with other hygrometers to ± 10 % accuracy in the respective mixing ratio ranges. Furthermore, a quality check procedure for high total water measurements in cirrus clouds at high pressures (400–500 hPa is introduced. The performance of FISH in the field is assessed by reviewing intercomparisons of FISH water vapor data with other in situ and remote sensing hygrometers over the last two decades. We find that the agreement of FISH with the other hygrometers has improved over that time span from overall up to ± 30 % or more to about ± 5–20 % @ 10 ppmv. As presented here, the robust and continuous calibration and operation procedures of the FISH instrument over the last two decades establish the

Vaporization study on vanadium-oxygen solid solution by mass spectrometric method

International Nuclear Information System (INIS)

Banchorndhevakul, W.; Matsui, Tsuneo; Naito, Keiji

1986-01-01

The vapor pressures over vanadium-oxygen solid solution (0.001 ≤ O/V ≤ 0.145) were measured by mass-spectrometric method in the temperature range of 1,855 ∼ 2,117 K. The main vapor species were observed to be V(g) and VO(g). The vapor pressure of V(g) is higher than that of VO(g) over the solid solutions with all O/V ratios except for O/V = 0.145. The vapor pressure of V(g) is nearly independent of O/V ratio. The vapor pressure of VO(g) decreases with decreasing O/V ratio. The oxygen partial pressure was calculated as a function of temperature and O/V ratio from the vapor pressures of V(g) and VO(g), from which the partial molar enthalpy and entropy of oxygen in the solid solution were determined. The partial molar enthalpy of oxygen was observed to be independent of composition, suggesting the presence of very weak interaction between interstitial oxygens. The compositional dependence of the partial molar entropy of oxygen can be explained by assuming the occupation of the octahedral site in bcc vanadium lattice by the interstitial oxygens. The excess partial molar entropy of oxygen was compared with the value derived from the sum of the contributions from the volume expansion, electronic heat capacity and vibrational terms. (author)

Adsorption of radon and water vapor on commercial activated carbons

International Nuclear Information System (INIS)

Hassan, N.M.; Ghosh, T.K.; Hines, A.L.; Loyalka, S.K.

1995-01-01

Equilibrium adsorption isotherms are reported for radon and water vapor on two commercial activated carbons: coconut shell Type PCB and hardwood Type BD. The isotherms of the water vapor were measured gravimetrically at 298 K. The isotherms of radon from dry nitrogen were obtained at 293, 298, and 308 K while the data for the mixture of radon and water vapor were measured at 298 K. The concentrations of radon in the gas and solid phases were measured simultaneously, once the adsorption equilibrium and the radioactive equilibrium between the radon and its daughter products were established. The shape of the isotherms was of Type III for the radon and Type V for the water vapor, according to Brunauer's classification. The adsorption mechanism was similar for both the radon and the water vapor, being physical adsorption on the macropore surface area in the low pressure region and micropore filling near saturation pressure. The uptake capacity of radon decreased both with increasing temperature and relative humidity. The heat of adsorption data indicated that the PCB- and the BD-activated carbons provided a heterogeneous surface for radon adsorption. The equilibrium data for radon were correlated with a modified Freundlich equation

Prediction of high pressure vapor-liquid equilibria with mixing rule using ASOG group contribution method

Energy Technology Data Exchange (ETDEWEB)

Tochigi, K.; Kojima, K.; Kurihara, K.

1985-02-01

To develop a widely applicable method for predicting high-pressure vapor-liquid equilibria by the equation of state, a mixing rule is proposed in which mixture energy parameter ''..cap alpha..'' of theSoave-RedlichKwong, Peng-Robinson, and Martin cubic equations of state is expressed by using the ASOG group contribution method. The group pair parameters are then determined for 14 group pairs constituted by six groups, i.e. CH/sub 4/, CH/sub 3/, CH/sub 2/, N/sub 2/, H/sub 2/, and CO/sub 2/ groups. By using the group pair parameters determined, high-pressure vapor-liquid equilibria are predicted with good accuracy for binary and ternary systems constituted by n-paraffins, nitrogen, hydrogen, and carbon dioxide in the temperature range of 100 - 450K.

Thermodynamic Modeling and Mechanical Design of a Liquid Nitrogen Vaporization and Pressure Building Device

Science.gov (United States)

Leege, Brian J.

The design of a liquid nitrogen vaporization and pressure building device that has zero product waste while recovering some of its stored energy is of interest for the cost reduction of nitrogen for use in industrial processes. Current devices may waste up to 30% of the gaseous nitrogen product by venting it to atmosphere. Furthermore, no attempt is made to recover the thermal energy available in the coldness of the cryogen. A seven step cycle with changing volumes and ambient heat addition is proposed, eliminating all product waste and providing the means of energy recovery from the nitrogen. This thesis discusses the new thermodynamic cycle and modeling as well as the mechanical design and testing of a prototype device. The prototype was able to achieve liquid nitrogen vaporization and pressurization up to 1000 psi, while full cycle validation is ongoing with promising initial results.

High-Pressure Water-Vapor Annealing for Enhancement of a-Si:H Film Passivation of Silicon Surface

International Nuclear Information System (INIS)

Guo Chun-Lin; Wang Lei; Zhang Yan-Rong; Zhou Hai-Feng; Liang Feng; Yang Zhen-Hui; Yang De-Ren

2014-01-01

We investigate the effect of amorphous hydrogenated silicon (a-Si:H) films passivated on silicon surfaces based on high-pressure water-vapor annealing (HWA). The effective carrier lifetime of samples reaches the maximum value after 210°C, 90min HWA. Capacitance-voltage measurement reveals that the HWA not only greatly reduces the density of interface states (D it ), but also decreases the fixed charges (Q fixed ) mainly caused by bulk defects. The change of hydrogen and oxygen in the film is measured by a spectroscopic ellipsometer and a Fourier-transform infrared (FTIR) spectrometer. All these results show that HWA is a useful method to improve the passivation effect of a-Si:H films deposited on silicon surfaces

Study on the effect of subcooling on vapor film collapse on high temperature particle surface

International Nuclear Information System (INIS)

Abe, Yutaka; Tochio, Daisuke; Yanagida, Hiroshi

2000-01-01

Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface is needed to be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcooling condition is qualitatively different from the vapor film collapse behavior in high subcooling condition. In case of vapor film collapse by pressure pulse, homogeneous vapor generation occurred all over the surface of steel particle in low subcooling condition. On the other hand, heterogeneous vapor generation was observed for higher subcooling condition. In case of vapor film collapse spontaneously, fluctuation of the gas-liquid interface after quenching propagated from bottom to top of the steel particle heterogeneously in low subcooling condition. On the other hand, simultaneous vapor generation occurred for higher subcooling condition. And the time transient of pressure, particle surface temperature, water temperature and visual information were simultaneously measured in the vapor film collapse experiment by external pressure pulse. Film thickness was estimated by visual data processing technique with the pictures taken by the high-speed video camera. Temperature and heat flux at the vapor-liquid interface were estimated by solving the heat condition equation with the measured pressure, liquid temperature and vapor film thickness as boundary conditions. Movement of the vapor-liquid interface were estimated with the PIV technique with the visual observation

Isosteric Vapor Pressure – Temperature Data for Water Sorption in Hardened Cement Paste: Enthalpy, Entropy and Sorption Isotherms at Different Temperatures

DEFF Research Database (Denmark)

Radjy, Fariborz; Sellevold, Erik J.; Hansen, Kurt Kielsgaard

. The accuracies for pressure, enthalpy and entropy are found to be 0.5% or less. PART II: The TPA-system has been used to generate water vapor pressure – temperature data for room temperature – and steam cured hardened cement pastes as well as porous vycor glass. The moisture contents range from saturated to dry...... and the temperatures range from 2 to 95 °C, differing for the specimen types. The data has been analyzed to yield differential enthalpy and entropy of adsorption, as well as the dependence of the relative vapor pressure on temperature at various constant moisture contents. The implications for the coefficient......PART I: In order to generate isosteric (constant mass) vapor pressure – temperature data (P-T data) for adsorbed pore water in hydrated cement paste, the Thermo Piestic Analysis system (the TPA system) described herein was developed. The TPA system generates high precision equilibrium isosteric P...

Thermodynamics of the vaporization of uranium tetrabromide

International Nuclear Information System (INIS)

Singh, Z.; Prasad, R.; Venugopal, P.V.; Roy, K.N.; Sood, D.D.

1981-01-01

Vapour pressures of solid and liquid uranium tetrabromide have been measured in the temperature range of 696 to 805 K and 805 to 1003 K respectively by transpiration and evaporation-temperature techniques. The vapour pressures obtained by the two techniques are in good agreement and have been combined to give the reported vapour-pressure equations for solid and liquid uranium tetrabromide. The melting temperature, the normal boiling temperature, the standard enthalpy of vaporization ΔH 0 (vap, 298.15 K), and the standard entropy of vaporization ΔS 0 (vap, 298.15 K) are reported. The enthalpy of fusion ΔH 0 (fus, 802 K) is also reported. The thermodynamic quantities from the present study are compared with those in the literature and critically analysed. (author)

Reduced-pressure chemical vapor deposition of boron-doped Si and Ge layers

International Nuclear Information System (INIS)

Bogumilowicz, Y.; Hartmann, J.M.

2014-01-01

We have studied the in-situ boron (B) doping of germanium (Ge) and silicon (Si) in Reduced Pressure-Chemical Vapor Deposition. Three growth temperatures have been investigated for the B-doping of Ge: 400, 600 and 750 °C at a constant growth pressure of 13300 Pa (i.e. 100 Torr). The B concentration in the Ge:B epilayer increases linearly with the diborane concentration in the gaseous phase. Single-crystalline Ge:B layers with B concentrations in-between 9 ∙ 10 17 and 1 ∙ 10 20 cm −3 were achieved. For the in-situ B doping of Si at 850 °C, two dichlorosilane mass flow ratios (MFR) have been assessed: F[SiH 2 Cl 2 ]/F[H 2 ] = 0.0025 and F[SiH 2 Cl 2 ]/F[H 2 ] = 0.0113 at a growth pressure of 2660 Pa (i.e. 20 Torr). Linear boron incorporation with the diborane concentration in the gas phase has been observed and doping levels in-between 3.5 ∙ 10 17 and 1 ∙ 10 20 cm −3 were achieved. We almost kept the same ratio of B versus Si atoms in the gas phase and in the Si epilayer. By contrast, roughly half of the B atoms present in the gas phase were incorporated in the Ge:B layers irrespective of the growth temperature. X-Ray Diffraction (XRD) allowed us to extract from the angular position of the Ge:B layer diffraction peak the substitutional B concentration. Values close to the B concentrations obtained by 4-probe resistivity measurements were obtained. Ge:B layers were smooth (< 1 m root mean square roughness associated with 20 × 20 μm 2 Atomic Force Microscopy images). Only for high F[B 2 H 6 ]/F[GeH 4 ] MFR (3.2 10 −3 ) did the Ge:B layers became rough; they were however still mono-crystalline (XRD). Above this MFR value, Ge:B layers became polycrystalline. - Highlights: • Boron doping of germanium and silicon in Reduced Pressure-Chemical Vapor Deposition • Linear boron incorporation in Ge:B and Si:B with the diborane flow • Single-crystal Ge:B layers with B concentrations in-between 9 ∙ 10 17 and 1 ∙ 10 20 cm −3 • Single-crystal Si

Vapour pressures and enthalpies of vaporization of a series of the linear n-alkyl acetates

Czech Academy of Sciences Publication Activity Database

Krasnykh, E. L.; Verevkin, S. P.; Koutek, Bohumír; Doubský, Jan

2006-01-01

Roč. 38, č. 6 (2006), s. 717-723 ISSN 0021-9614 Institutional research plan: CEZ:AV0Z40550506 Keywords : aliphatic acetates * transpiration method * vapour pressure * enthalpy of vaporization Subject RIV: CC - Organic Chemistry Impact factor: 1.842, year: 2006

Effect of Preferential Solvation of Polymer Chains on Vapor-Pressure Osmometry Results. Computer Simulation Study.

Czech Academy of Sciences Publication Activity Database

Svoboda, Martin; Lísal, Martin; Limpouchová, Z.; Procházka, Karel

2018-01-01

Roč. 23, č. 3 (2018), s. 244-251 ISSN 1023-666X R&D Projects: GA ČR GA15-19542S Institutional support: RVO:67985858 Keywords : vapor-pressure osmometry * simulation * solvatation Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry

Dynamic of vapor bubble growth in fields of variable pressure

International Nuclear Information System (INIS)

Pedroso, H.K.

1982-01-01

A mathematical model for the description of the growth from an initial nucleus of a vapor bubble imersed in liquid, subjected to a loss of pressure is presented. The model is important for analysing LOCA (Loss of Coolant Acident) in P.W.R. type reactors. Several simplifications were made in the phenomenum governing equations. With such simplifications the heat diffusion equation became the determining factor for the bubble growth, and the problem was reduced to solve the heat diffusion equation for semi infinite solid whose surface temperature is a well known function of time (it is supposed that the surface temperature is equal to the saturation temperature of the liquid at the system pressure at a given moment). The model results in an analytical expression for the bubble radius as a function of time. Comparisons with experimental data and previous models were made, with reasonable agreement. (author) [pt

Vaporization of liquid Pb-Li eutectic alloy from 1000K to 1200K - A high temperature mass spectrometric study

Science.gov (United States)

Jain, U.; Mukherjee, A.; Dey, G. K.

2017-09-01

Liquid lead-lithium eutectic will be used as a coolant in fusion reactor blanket loop. Vapor pressure of the eutectic is an important parameter to accurately predict its in-loop behavior. Past measurements of vapor pressure of the eutectic relied on indirect methods. In this paper, we report for the first time the in-situ vaporization behavior of the liquid alloy between 1042 and 1176 K by Knudsen effusion mass spectrometry (KEMS). It was seen that the vaporization occurred by independent evaporation of lead and lithium. No complex intermetallic vapor was seen in the mass spectra. The partial pressures and enthalpy of vaporization of Pb and Li were evaluated directly from the measured ion intensities formed from the equilibrium vapor over the alloy. The activity of Li over a temperature range of 1042-1176 K was found to be 4.8 × 10-5 to that of pure Li, indicating its very low activity in the alloy.

Vapor pressures and standard molar enthalpies, entropies and Gibbs energies of sublimation of two hexachloro herbicides using a TG unit

International Nuclear Information System (INIS)

Vecchio, Stefano

2010-01-01

The vapor pressures above the solid hexachlorobenzene (HCB) and above both the solid and liquid 1,2,3,4,5,6-hexachlorocyclohexane (lindane) were determined in the ranges 332-450 K and 347-429 K, respectively, by measuring the mass loss rates recorded by thermogravimetry under both isothermal and nonisothermal conditions. The results obtained were compared with those taken from literature. From the temperature dependence of vapor pressure derived by the experimental thermogravimetry data the molar enthalpies of sublimation Δ cr g H m o ( ) were selected for HCB and lindane as well as the molar enthalpy of vaporization Δ l g H m o ( ) for lindane only, at the middle of the respective temperature intervals. The melting temperatures and the molar enthalpies of fusion Δ cr l H m o (T fus ) of lindane were measured by differential scanning calorimetry. Finally, the standard molar enthalpies of sublimation Δ cr g H m o (298.15 K) were obtained for both chlorinated compounds at the reference temperature of 298.15 K using the Δ cr g H m o ( ), Δ l g H m o ( ) and Δ cr l H m o (T fus ) values, as well as the heat capacity differences between gas and liquid and the heat capacity differences between gas and solid, Δ l g C p,m o and Δ cr g C p,m o , respectively, both estimated by applying a group additivity procedure. Therefore, the averages of the standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs energies of sublimation at 298.15 K, have been derived.

Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

Energy Technology Data Exchange (ETDEWEB)

Georgi, Colin [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Hapke, Marko; Thiel, Indre [Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, Rostock 18059 (Germany); Hildebrandt, Alexander [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Institute of Electronic Nano Systems (ENAS), Technologie-Campus 3, Chemnitz 09126 (Germany); Technische Universität Chemnitz, Center for Microtechnologies (ZfM), Chemnitz 09107 (Germany); Lang, Heinrich, E-mail: heinrich.lang@chemie.tu-chemnitz.de [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany)

2015-03-02

A series of cobalt half-sandwich complexes of type [Co(η{sup 5}-C{sub 5}H{sub 5})(L)(L′)] (1: L, L′ = 1,5-hexadiene; 2: L = P(OEt){sub 3}, L′ = H{sub 2}C=CHSiMe{sub 3}; 3: L = L′ = P(OEt){sub 3}) has been studied regarding their physical properties such as the vapor pressure, decomposition temperature and applicability within the metal-organic chemical vapor deposition (MOCVD) process, with a focus of the influence of the phosphite ligands. It could be shown that an increasing number of P(OEt){sub 3} ligands increases the vapor pressure and thermal stability of the respective organometallic compound. Complex 3 appeared to be a promising MOCVD precursor with a high vapor pressure and hence was deposited onto Si/SiO{sub 2} (100 nm) substrates. The resulting reflective layer is closed, dense and homogeneous, with a slightly granulated surface morphology. X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of metallic cobalt, cobalt phosphate, cobalt oxide and cobalt carbide. - Highlights: • Thermal studies and vapor pressure measurements of cobalt half-sandwich complexes was carried out. • Chemical vapor deposition with cobalt half-sandwich complexes is reported. • The use of Co-phosphites results in significant phosphorous-doped metallic layers.

Study of film boiling collapse behavior during vapor explosion

International Nuclear Information System (INIS)

Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi.

1996-06-01

Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

Low-pressure chemical vapor deposition as a tool for deposition of thin film battery materials

NARCIS (Netherlands)

Oudenhoven, J.F.M.; Dongen, van T.; Niessen, R.A.H.; Croon, de M.H.J.M.; Notten, P.H.L.

2009-01-01

Low Pressure Chemical Vapor Deposition was utilized for the deposition of LiCoO2 cathode materials for all-solid-state thin-film micro-batteries. To obtain insight in the deposition process, the most important process parameters were optimized for the deposition of crystalline electrode films on

Radioisotope labeling technique for vapor density measurements of volatile inorganic species

International Nuclear Information System (INIS)

Peterson, E.J.; Caird, J.A.; Hessler, J.P.; Hoekstra, H.R.; Williams, C.W.

1979-01-01

A new method for complexed metal ion vapor density measurement involving labeling the metal ions of interest with a radioactive isotope is described. The isotope chosen in the present work is unstable and leads to emission of a characteristic γ ray. Thus the γ-counting rate was related to the number density of complexed metal ions in the vapor phase. This technique is applicable to the study of any volatile inorganic species, but in the present study has been used to measure vapor densities of complex species in the TbCl 3 -AlCl 3 system by using tracer 160 Tb. 4 figures, 2 tables

Released air during vapor and air cavitation

Energy Technology Data Exchange (ETDEWEB)

Jablonská, Jana, E-mail: jana.jablonska@vsb.cz; Kozubková, Milada, E-mail: milada.kozubkova@vsb.cz [VŠB-Technical University of Ostrava, Faculty of Mechanical Engineering, Department of Hydromechanics and Hydraulic Equipment, 17. listopadu 15, 708 33 Ostrava-Poruba (Czech Republic)

2016-06-30

Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurements for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ε model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.

Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

DEFF Research Database (Denmark)

Bilde, Merete; Zardini, Alessandro Alessio; Hong, Juan

alcohols. These polyols are common in the water soluble fraction of atmospheric aerosols. In our experimental system sub-micron particles are generated by nebulization from aqueous solution, and a mono disperse fraction of the aerosol is selected using a differential mobility analyzer. The particles......The atmospheric partitioning between gas and condensed phase of organic molecules is poorly understood, and discrepancies exist between predicted and observed concentrations of secondary organic aerosols. A key problem is the lack of information about thermodynamic properties of semi- and low...... volatile organic molecules. Saturation vapor pressure and the associated temperature dependence (dH) are key parameters for improving predictive atmospheric models. In this work we combine experiments and thermodynamic modeling to investigate these parameters for a series of polyols, so-called sugar...

Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Hemawan, Kadek W.; Gou, Huiyang; Hemley, Russell J. [Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington, DC 20015 (United States)

2015-11-02

Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH{sub 4}/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H{sub 2} into the deposition gas chemistry. Electronically excited species of CN, C{sub 2}, Ar, N{sub 2}, CH, H{sub β}, and H{sub α} were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T{sub 2g} phonon at 1333 cm{sup −1} peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm.

Equilibrium water vapor pressures over polyvanadates M2V12O30.7·nH2O

International Nuclear Information System (INIS)

Volkov, V.L.; Zakharova, G.S.; Ivakin, A.A.

1986-01-01

Equilibrium pressures of water vapors over polyvanadates M 2 V 12 O 30.7 xnH 2 O where M=Li, Na, K are determined in the 293-343 K temperature range. Changes in Gibbs free energy and enthalpy of compound dehydration depending on water content in the final product are calculated on the basis of these data. Molar enthalpy of water is shown to reduce from lithium to potassium, while equilibrium pressure of water vapors over the compounds grows from lithium to potassium. Good correlation of thermodynamic properties of crystallization water of polyvanadates with energy characteristics of hydrated M + ions of the solutions confirms the conclusion that they cannot be attributed to ordinary crystallohydrates

Vaporization study on vanadium monoxide and two-phase mixture of vanadium and vanadium monoxide by mass-spectrometric method

International Nuclear Information System (INIS)

Banchorndhevakul, W.; Matsui, Tsuneo; Naito, Keiji

1986-01-01

The vapor pressures over single phase vanadium monoxide VO 1.022 (s) and the two-phase mixture of vanadium metal (β phase) and vanadium monoxide were measured by mass-spectrometric method in the temperature range of 1,803 ∼ 1,990 and 1,703 ∼ 1,884 K, respectively. The main gas species over both systems were found to be VO(g) and V(g). The vapor pressure of VO(g) over the two-phase mixture of V(s) and VO(s) was a little lower than that over single phase VO(s). The vapor pressure of V(g) over the two-phase mixture was nearly equal to that over single phase. From the vapor pressure data, the enthalpies of vaporization, the enthalpies of formation for VO(g) and V(g) and the dissociation energy of VO(g) were determined. The oxygen partial pressure was calculated as a function of temperature from the vapor pressures of VO(g) and V(g), from which the partial molar enthalpies and entropies of oxygen in both systems were obtained. (author)

Vapor cell geometry effect on Rydberg atom-based microwave electric field measurement

Science.gov (United States)

Zhang, Linjie; Liu, Jiasheng; Jia, Yue; Zhang, Hao; Song, Zhenfei; Jia, Suotang

2018-03-01

The geometry effect of a vapor cell on the metrology of a microwave electric field is investigated. Based on the splitting of the electromagnetically induced transparency spectra of cesium Rydberg atoms in a vapor cell, high-resolution spatial distribution of the microwave electric field strength is achieved for both a cubic cell and a cylinder cell. The spatial distribution of the microwave field strength in two dimensions is measured with sub-wavelength resolution. The experimental results show that the shape of a vapor cell has a significant influence on the abnormal spatial distribution because of the Fabry–Pérot effect inside a vapor cell. A theoretical simulation is obtained for different vapor cell wall thicknesses and shows that a restricted wall thickness results in a measurement fluctuation smaller than 3% at the center of the vapor cell. Project supported by the National Key Research and Development Program of China (Grant Nos. 2017YFA03044200 and 2016YFF0200104), the National Natural Science Foundation of China (Grant Nos. 91536110, 61505099, and 61378013), and the Fund for Shanxi “331 Project” Key Subjects Construction, China.

Experimental vapor pressures (from 1 Pa to 100 kPa) of six saturated Fatty Acid Methyl Esters (FAMEs): Methyl hexanoate, methyl octanoate, methyl decanoate, methyl dodecanoate, methyl tetradecanoate and methyl hexadecanoate

International Nuclear Information System (INIS)

Sahraoui, Lakhdar; Khimeche, Kamel; Dahmani, Abdallah; Mokbel, Ilham; Jose, Jacques

2016-01-01

Highlight: • Vapor-liquid equilibria, Enthalpy of Vaporization, saturated Fatty Acid Methyl Ester. - Abstract: Vapor pressures of six saturated Fatty Acid Methyl Esters (FAMEs), methyl hexanoate (or methyl caproate), methyl octanoate (or methyl caprylate), Methyl decanoate (or methyl caprate), methyl dodecanoate (or methyl laurate), methyl tetradecanoate (or methyl myristate), and methyl hexadecanoate (or methyl palmitate) were measured from 1 Pa to 100 kPa and at temperature range between 262 and 453 K using a static apparatus. The experimental data (P-T) were compared with the available literature data.

Effect of impact angle on vaporization

Science.gov (United States)

Schultz, Peter H.

1996-09-01

Impacts into easily vaporized targets such as dry ice and carbonates generate a rapidly expanding vapor cloud. Laboratory experiments performed in a tenuous atmosphere allow deriving the internal energy of this cloud through well-established and tested theoretical descriptions. A second set of experiments under near-vacuum conditions provides a second measure of energy as the internal energy converts to kinetic energy of expansion. The resulting data allow deriving the vaporized mass as a function of impact angle and velocity. Although peak shock pressures decrease with decreasing impact angle (referenced to horizontal), the amount of impact-generated vapor is found to increase and is derived from the upper surface. Moreover, the temperature of the vapor cloud appears to decrease with decreasing angle. These unexpected results are proposed to reflect the increasing roles of shear heating and downrange hypervelocity ricochet impacts created during oblique impacts. The shallow provenance, low temperature, and trajectory of such vapor have implications for larger-scale events, including enhancement of atmospheric and biospheric stress by oblique terrestrial impacts and impact recycling of the early atmosphere of Mars.

Vaporization of niobium dioxide by mass-effusion and mass-spectrometric methods

International Nuclear Information System (INIS)

Kamegashira, N.; Matsui, T.; Harada, M.; Naito, K.

1981-01-01

The congruence of the vaporization process of NbO, NbO 2 , Nb 12 O 29 and Nb 2 O 5 in the niobium-oxygen system was investigated from the phase change of the solid residue after vaporization, and it was observed that only the NbO 2 phase vaporizes congruently. The vapor pressures over NbO 2 (s) were measured by means of a combination of mass-effusion (weight loss measurement) and mass-spectrometric methods in the temperature range 1953-2323 K. By applying the second and the third law treatments of thermodynamics to the partial pressures of the gaseous species NbO 2 (g), NbO(g) and O(g), the enthalpies of vaporization for the reactions NbO 2 (s,1)=NbO 2 (g) and NbO 2 (s,1)=NbO(g)+O(g), were calculated. From these data the enthalpies of formation and the dissociation energies of NbO 2 (g) and NbO(g) were also determined. The uncertainties included in the third law treatment were discussed, and the results calculated by the third law treatment using the most reliable data available at present were presented. (orig.)

New approaches to the study of lanthanide/actinide chloride: aluminum chloride vapor phase complexes

International Nuclear Information System (INIS)

Peterson, E.J.; Caird, J.A.; Carnall, W.T.; Hessler, J.P.; Hoekstra, H.R.; Williams, C.W.

1979-01-01

The spectrophotometric technique for vapor density measurements of complexed metal ions has been reformulated to account for temperature dependent effects and multi-species systems. Analysis of vapor pressure information indicates that the NdCl 3 --AlCl 3 and HoCl 3 --AlCl 3 systems are adequately explained by the existence of three vapor species. The two higher molecular weight complexes LnAl 4 Cl 15 and LnAl 3 Cl 12 were first proposed by Oeye and Gruen. The newly identified higher temperature species, HoAl 2 Cl 9 , contributes significantly to the vapor density above 750 0 K and below 3 atm of dimer pressure. In view of the consistency of the Nd +3 and Ho +3 chemistry the data for the Sm +3 system should be viewed with reservation. A new method for vapor density measurements involving use of radioactive tracers has been discussed in terms of its applicability to the study of (Ln,An)Cl 3 (AlCl 3 )/sub x/ systems

Thermodynamic study of sublimation, melting and vaporization of scandium(III) dipivaloylmethanate derivatives

International Nuclear Information System (INIS)

Zherikova, Kseniya V.; Zelenina, Ludmila N.; Chusova, Tamara P.; Gelfond, Nikolay V.; Morozova, Natalia B.

2016-01-01

Highlights: • Thermal properties of two volatile fluorinated Sc(III) beta-diketonates were studied. • Saturated and unsaturated vapor pressures were measured. • DSC analysis was carried out. • Sublimation, evaporation and melting enthalpies and entropies were derived. • Effect of fluorine introduction on volatility and thermal stability was established. - Abstract: The present work deals with the investigation of thermal properties of two volatile scandium(III) beta-diketonates with 2,2,6,6-tetramethyl-4-fluoro-3,5-heptanedione and 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione which have been synthesized and purified. Using the static method with glass membrane gauge-manometer the temperature dependencies of saturated and unsaturated vapor pressure were measured for the first time. The temperatures and enthalpies of melting were measured for these compounds by differential scanning calorimetry. The standard thermodynamic characteristics of enthalpy and entropy for sublimation, vaporization and melting processes were derived.

Risk evaluation on the basis of pressure rate measured by automatic pressure tracking adiabatic calorimeter.

Science.gov (United States)

Iwata, Yusaku; Koseki, Hiroshi

2008-11-15

An automatic pressure tracking adiabatic calorimeter (APTAC) had been employed to obtain the thermokinetic and the vapor pressure data during runaway reactions. The APTAC is an adiabatic calorimeter with a large-scale sample mass and low thermal inertia, and is an extremely useful tool for assessing thermal hazards of reactive chemicals. The data obtained by the APTAC are important information for the design of the safe industrial process. The thermodynamics parameters and the gas production were discussed on the basis of the experimental data of various concentrations and weights of di-tert-butyl peroxide (DTBP)/toluene solution for the purpose of investigating the properties of the APTAC data. The thermal decomposition of DTBP was studied on the basis of the temperature data and the pressure data obtained by the APTAC. The activation energy and the frequency factor of DTBP are nearly constant and the same as the literature values in the concentrations between 20 and 60 wt.%. The pressure rise due to gas production is important data for designing the relief vent of a reactor. The time history of the gas production was investigated with various weights and concentrations. The total gas production index, which had the vapor pressure correction, was 1.0 in the decomposition of DTBP.

Risk evaluation on the basis of pressure rate measured by automatic pressure tracking adiabatic calorimeter

International Nuclear Information System (INIS)

Iwata, Yusaku; Koseki, Hiroshi

2008-01-01

An automatic pressure tracking adiabatic calorimeter (APTAC) had been employed to obtain the thermokinetic and the vapor pressure data during runaway reactions. The APTAC is an adiabatic calorimeter with a large-scale sample mass and low thermal inertia, and is an extremely useful tool for assessing thermal hazards of reactive chemicals. The data obtained by the APTAC are important information for the design of the safe industrial process. The thermodynamics parameters and the gas production were discussed on the basis of the experimental data of various concentrations and weights of di-tert-butyl peroxide (DTBP)/toluene solution for the purpose of investigating the properties of the APTAC data. The thermal decomposition of DTBP was studied on the basis of the temperature data and the pressure data obtained by the APTAC. The activation energy and the frequency factor of DTBP are nearly constant and the same as the literature values in the concentrations between 20 and 60 wt.%. The pressure rise due to gas production is important data for designing the relief vent of a reactor. The time history of the gas production was investigated with various weights and concentrations. The total gas production index, which had the vapor pressure correction, was 1.0 in the decomposition of DTBP

Volatilization of multicomponent mixtures in soil vapor extraction applications

International Nuclear Information System (INIS)

Bass, D.H.

1995-01-01

In soil vapor extraction (SVE) applications involving multicomponent mixtures, prediction of mass removal by volatilization as a function remediation extent is required to estimate remediation time and to size offgas treatment equipment. SVE is a commonly used remediation technology which volatilizes and enhances aerobic biodegradation of contamination adsorbed to vadose zone soils. SVE is often applied at sites contaminated with petroleum products, which are usually mixtures of many different compounds with vapor pressures spanning several orders of magnitude. The most volatile components are removed first, so the vapor pressure of the remaining contaminant continually decreases over the course of the remediation. A method for assessing how vapor pressure, and hence the rate of volatilization, of a multicomponent mixture changes over the course of a vapor extraction remedy has been developed. Each component is listed, alone, with its mass fraction in the mixture, in decreasing order of pure component vapor pressure (where component analyses are unavailable, model compounds can be used), For most petroleum distillates, the vapor pressure for each component plotted against the cumulative mass fraction of the component in the mixture on semilog coordinates will produce a straight line with a high correlation coefficient. This regression can be integrated to produce an expression for vapor pressure of the overall mixture as a function of extent or remediation

Robust design for shape parameters of high pressure thermal vapor compressor by numerical analysis

International Nuclear Information System (INIS)

Park, Il Seouk

2008-01-01

A high motive pressure Thermal Vapor Compressor(TVC) for a commercial Multi-Effect Desalination(MED) plant is designed to have a high entraining performance and its robustness is also considered in the respect of operating stability at the abrupt change of the operating pressures like the motive and suction steam pressure which can be easily fluctuated by the external disturbance. The TVC having a good entraining performance of more than entrainment ratio 6.0 is designed through the iterative CFD analysis for the various primary nozzle diameter, mixing tube diameter and mixing tube length. And then for a couple of TVC having a similar entrainment ratio, the changes of the entrainment ratio are checked along the motive and suction pressure change. The system stability is diagnosed through the analyzing the changing pattern of the entrainment ratio

Growth of GaN layers using Ga2O vapor obtained from Ga and H2O vapor

International Nuclear Information System (INIS)

Sumi, Tomoaki; Taniyama, Yuuki; Takatsu, Hiroaki; Juta, Masami; Kitamoto, Akira; Imade, Mamoru; Yoshimura, Masashi; Mori, Yusuke; Isemura, Masashi

2015-01-01

In this study, we performed growth of GaN layers using Ga 2 O vapor synthesized from Ga and H 2 O vapor. In this process, we employed H 2 O vapor instead of HCl gas in hydride vapor phase epitaxy (HVPE) to synthesize Ga source gas. In the synthesis reaction of Ga 2 O, a Ga 2 O 3 whisker formed and covered Ga, which impeded the synthesis reaction of Ga 2 O. The formation of the Ga 2 O 3 whisker was suppressed in H 2 ambient at high temperatures. Then, we adopted this process to supply a group III precursor and obtained an epitaxial layer. X-ray diffraction (XRD) measurement revealed that the epitaxial layer was single-crystalline GaN. Growth rate increased linearly with Ga 2 O partial pressure and reached 104 µm/h. (author)

Water vapor retrieval from near-IR measurements of polarized scanning atmospheric corrector

Science.gov (United States)

Qie, Lili; Ning, Yuanming; Zhang, Yang; Chen, Xingfeng; Ma, Yan; Li, Zhengqiang; Cui, Wenyu

2018-02-01

Water vapor and aerosol are two key atmospheric factors effecting the remote sensing image quality. As water vapor is responsible for most of the solar radiation absorption occurring in the cloudless atmosphere, accurate measurement of water content is important to not only atmospheric correction of remote sensing images, but also many other applications such as the study of energy balance and global climate change, land surface temperature retrieval in thermal remote sensing. A multi-spectral, single-angular, polarized radiometer called Polarized Scanning Atmospheric Corrector (PSAC) were developed in China, which are designed to mount on the same satellite platform with the principle payload and provide essential parameters for principle payload image atmospheric correction. PSAC detect water vapor content via measuring atmosphere reflectance at water vapor absorbing channels (i.e. 0.91 μm) and nearby atmospheric window channel (i.e. 0.865μm). A near-IR channel ratio method was implemented to retrieve column water vapor (CWV) amount from PSAC measurements. Field experiments were performed at Yantai, in Shandong province of China, PSAC aircraft observations were acquired. The comparison between PSAC retrievals and ground-based Sun-sky radiometer measurements of CWV during the experimental flights illustrates that this method retrieves CWV with relative deviations ranging from 4% 13%. This method retrieve CWV more accurate over land than over ocean, as the water reflectance is low.

Investigation of the vaporization of boric acid by transpiration thermogravimetry and knudsen effusion mass spectrometry.

Science.gov (United States)

Balasubramanian, R; Lakshmi Narasimhan, T S; Viswanathan, R; Nalini, S

2008-11-06

The vaporization of H3BO3(s) was studied by using a commercial thermogravimetric apparatus and a Knudsen effusion mass spectrometer. The thermogravimetric measurements involved use of argon as the carrier gas for vapor transport and derivation of vapor pressures of H3BO3(g) in the temperature range 315-352 K through many flow dependence and temperature dependence runs. The vapor pressures as well as the enthalpy of sublimation obtained in this study represent the first results from measurements at low temperatures that are in accord with the previously reported near-classical transpiration measurements (by Stackelberg et al. 70 years ago) at higher temperatures (382-413 K with steam as the carrier gas). The KEMS measurements performed for the first time on boric acid showed H3BO3(g) as the principal vapor species with no meaningful information discernible on H2O(g) though. The thermodynamic parameters, both p(H3BO3) and Delta sub H degrees m(H3BO3,g), deduced from KEMS results in the temperature range 295-342 K are in excellent agreement with the transpiration results lending further credibility to the latter. All this information points toward congruent vaporization at the H3BO3 composition in the H2O-B2O3 binary system. The vapor pressures obtained from transpiration (this study and that of Stackelberg et al.) as well as from KEMS measurements are combined to recommend the following: log [p(H3BO3)/Pa]=-(5199+/-74)/(T/K)+(15.65+/-0.23), valid for T=295-413 K; and Delta sub H degrees m=98.3+/-9.5 kJ mol (-1) at T=298 K for H3BO3(s)=H3BO3(g).

The Activity and Enthalpy of Vaporization of Nicotine from Tobacco at Moderate Temperatures

Directory of Open Access Journals (Sweden)

St.Charles F. Kelley

2016-01-01

Full Text Available The vapor pressure of nicotine has been reported for unprotonated nicotine and for nicotine-water solutions. Yet no published values exist for nicotine in any commercially relevant matrix or for protonated forms (e.g., tobacco, smoke, electronic cigarette solutions, nicotine replacement products, nicotine salts. Therefore a methodology was developed to measure nicotine activity (defined as the vapor pressure from a matrix divided by the vapor pressure of pure nicotine. The headspace concentration of nicotine was measured for pure nicotine and tobacco stored at 23, 30, and 40 °C which allowed for conversion to vapor pressure and nicotine activity and for the estimation of enthalpy of vaporization. Burley, Flue-cured, Oriental, and cigarette blends were tested. Experiments were conducted with pure nicotine initially until the storage and sampling techniques were validated by comparison with previously published values. We found that the nicotine activity from tobacco was less than 1% with Burley > Flue-cured > Oriental. At 23 °C the nicotine vapor pressure averaged by tobacco type was 0.45 mPa for Oriental tobacco, 1.8 mPa for Flue-cured, 13 mPa for Burley while pure nicotine was 2.95 Pa. In general, the nicotine activity increased as the (calculated unprotonated nicotine concentration increased. The nicotine enthalpy of vaporization from tobacco ranged from 77 kJ/mol to 92 kJ/mol with no obvious trends with regard to tobacco origin, type, stalk position or even the wide range of nicotine activity. The mean value for all tobacco types was 86.7 kJ/mol with a relative standard deviation of 6.5% indicating that this was an intrinsic property of the nicotine form in tobacco rather than the specific tobacco properties. This value was about 30 kJ/mol greater than that of pure nicotine and is similar to the energy needed to remove a proton from monoprotonated nicotine.

Condensers for measuring steam quality at the inlet of back-pressure units of the Los Azufres, Mich., geothermal field; Condensadores para medir la calidad del vapor a la entrada de las turbinas a contrapresion del campo geotermico de Los Azufres, Mich.

Energy Technology Data Exchange (ETDEWEB)

Sandoval Medina, Fernando; Gonzalez Gonzalez, Rubi; Reyes Delgado, Lisette; Medina Martinez, Moises [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia de Los Azufres (Mexico)]. E-mail: fernando.sandoval@cfe.gob.mx

2007-01-15

Electrical conductivity is an indirect measurement of the quality of the steam supplied to power units. In the Los Azufres, Mich., geothermal field, the electrical conductivity once was measured in a discrete and periodic way by condensing steam samples through a water-cooled condenser. In an attempt to continuously measure conductivity, conductivity meters were installed where the units discharged, but the values proved unstable and unrepresentative. Thereafter, taking into account that steam quality should be measured at the steam delivery-reception point, equipment was designed and tested for continuously condensing steam. Finally it was possible to get an air-cooled condenser able to condense 500 milliliters per minute, enough to collect a representative flow of the steam and to measure its electrical conductivity. The equipment was installed in all seven back-pressure units operating in the field and to date has been operating in an optimal manner. [Spanish] La conductividad electrica es una medida indirecta de la calidad del vapor que se suministra a las unidades turbogeneradoras. En el campo geotermico de Los Azufres, Mich., la conductividad electrica se media en forma puntual y periodica, condensando muestras de vapor por medio de un serpentin enfriado con agua. Despues, ante la necesidad de medirla en forma continua, se instalaron conductivimetros en las descargas de las unidades, pero los valores resultaron muy inestables y poco representativos. Considerando, ademas, que la calidad del vapor debe medirse en el punto de entrega-recepcion, se disenaron y probaron equipos para condensar vapor de manera continua, lograndose construir un condensador enfriado por aire que logra condensar un flujo de 500 mililitros por minuto, cantidad suficiente para tener un flujo representativo del vapor que alimenta a las turbinas y medirle su conductividad electrica. Se instalaron estos equipos en las siete unidades turbogeneradoras a contrapresion que funcionan en el campo

Studies of molecular association in H2O and D2O vapors by measurement of thermal conductivity

International Nuclear Information System (INIS)

Curtiss, L.A.; Frurip, D.J.; Blander, M.

1979-01-01

The thermal conductivities of H 2 O and D 2 O vapors were measured in a modified thick hot wire cell between 358 and 386 K at pressures ranging from 100 to 1000 Torr. Analysis of the data indicates that molecular association to form a dimeric species is the main source of enhancement of the thermal conductivity of both vapors. The enthalpy and entropy of association of the H 2 O dimer are -3.59 kcal mol -1 and -18.59 cal deg -1 mol -1 , respectively. The enthalpy and entropy of association of the D 2 O dimer are -3.66 kcal mol -1 and -18.67 cal deg -1 mol -1 , respectively. The measured enthalpy of association of the H 2 O dimer is in agreement with recently reported ab initio molecular orbital calculations on the H 2 O dimer. The entropies of association of the H 2 O and D 2 O dimers are calculated theoretically and are found to be in agreement with the measured values

Preliminary characterization of an expanding flow of siloxane vapor MDM

Science.gov (United States)

Spinelli, A.; Cozzi, F.; Cammi, G.; Zocca, M.; Gaetani, P.; Dossena, V.; Guardone, A.

2017-03-01

The early experimental results on the characterization of expanding flows of siloxane vapor MDM (C8H24O2Si3, octamethyltrisiloxane) are presented. The measurements were performed on the Test Rig for Organic VApors (TROVA) at the CREA Laboratory of Politecnico di Milano. The TROVA test-rig was built in order to investigate the non-ideal compressible-fluid behavior of typical expanding flows occurring within organic Rankine cycles (ORC) turbine passages. The test rig implements a batch Rankine cycle where a planar converging-diverging nozzle replaces the turbine and represents a test section. Investigations related to both fields of non-ideal compressible-fluid dynamics fundamentals and turbomachinery are allowed. The nozzle can be operated with different working fluids and operating conditions aiming at measuring independently the pressure, the temperature and the velocity field and thus providing data to verify the thermo-fluid dynamic models adopted to predict the behavior of these flows. The limiting values of pressure and temperature are 50 bar and 400 °C respectively. The early measurements are performed along the nozzle axis, where an isentropic process is expected to occur. In particular, the results reported here refer to the nozzle operated in adapted conditions using the siloxane vapor MDM as working fluid in thermodynamic regions where mild to medium non-ideal compressible-fluid effects are present. Both total temperature and total pressure of the nozzle are measured upstream of the test section, while static pressure are measured along the nozzle axis. Schlieren visualizations are also carried out in order to complement the pressure measurement with information about the 2D density gradient field. The Laser Doppler Velocimetry technique is planned to be used in the future for velocity measurements. The measured flow field has also been interpreted by resorting to the quasi-one-dimensional theory and two dimensional CFD viscous calculation. In both cases

Vapor pressure of heat transfer fluids of absorption refrigeration machines and heat pumps: Binary solutions of lithium nitrate with methanol

International Nuclear Information System (INIS)

Safarov, Javid T.

2005-01-01

Vapor pressure p of LiNO 3 + CH 3 OH solutions at T = (298.15 to 323.15) K was reported, osmotic φ and activity coefficients γ; and activity of solvent a s have been evaluated. The experiments were carried out in molality range m = (0.18032 to 5.2369) mol . kg -1 . The Antoine equation was used for the empiric description of experimental vapor pressure results. The Pitzer-Mayorga model with inclusion of Archer's ionic strength dependence of the third virial coefficient was used for the description of calculated osmotic coefficients. The parameters of Archer extended Pitzer model were used for evaluation of activity coefficients

Water vapor absorption in the atmospheric window at 239 GHz

Science.gov (United States)

Bauer, A.; Godon, M.; Carlier, J.; Ma, Q.

1995-01-01

Absolute absorption rates of pure water vapor and mixtures of water vapor and nitrogen have been measured in the atmospheric window at 239 GHz. The dependence on pressure as well as temperature has been obtained. The experimental data are compared with several theoretical or empirical models, and satisfactory agreement is obtained with the models involving a continuum; in the case of pure water vapor, the continuum contribution based upon recent theoretical developments gives good results. The temperature dependence is stronger than that proposed in a commonly used atmospheric transmission model.

Pressure (Or No Royal Road)

Science.gov (United States)

Bradley, J.

1973-01-01

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

Two dimensional radial gas flows in atmospheric pressure plasma-enhanced chemical vapor deposition

Science.gov (United States)

Kim, Gwihyun; Park, Seran; Shin, Hyunsu; Song, Seungho; Oh, Hoon-Jung; Ko, Dae Hong; Choi, Jung-Il; Baik, Seung Jae

2017-12-01

Atmospheric pressure (AP) operation of plasma-enhanced chemical vapor deposition (PECVD) is one of promising concepts for high quality and low cost processing. Atmospheric plasma discharge requires narrow gap configuration, which causes an inherent feature of AP PECVD. Two dimensional radial gas flows in AP PECVD induces radial variation of mass-transport and that of substrate temperature. The opposite trend of these variations would be the key consideration in the development of uniform deposition process. Another inherent feature of AP PECVD is confined plasma discharge, from which volume power density concept is derived as a key parameter for the control of deposition rate. We investigated deposition rate as a function of volume power density, gas flux, source gas partial pressure, hydrogen partial pressure, plasma source frequency, and substrate temperature; and derived a design guideline of deposition tool and process development in terms of deposition rate and uniformity.

Vapor pressures of (3-(Dimethylamino)propyl)dimethylindium, (tert-Butylimino)bis(diethylamino)cyclopentadienyltantalum, and (tert-Butylimino)tris(ethylmethylamino)tantalum

Czech Academy of Sciences Publication Activity Database

Morávek, Pavel; Pangrác, Jiří; Fulem, Michal; Hulicius, Eduard; Růžička, K.

2014-01-01

Roč. 59, č. 12 (2014), s. 4179-4183 ISSN 0021-9568 Institutional support: RVO:68378271 Keywords : vapor pressure * static method * organometallics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.037, year: 2014

Correlation of dew- and bubble-point curves for binary refrigerant mixtures. [Correlation between dew-point pressure(saturated vapor state) and bubble-point pressure(saturated liquid state)]. Niseibunkei kongo reibai no roten oyobi futten kyokusen no sokan

Energy Technology Data Exchange (ETDEWEB)

Yada, N. (Kanagawa Institute of Technology, Kanagawa (Japan)); Watanabe, K. (Keio University, Tokyo (Japan). Faculty of Science and Technology)

1991-12-25

The paper makes a correlation expressing dew- and bubble-point curves using measured values for seven binary refrigerant freon-mixtures. In most binary systems at the same temperature, the pressure shows a different value between in a saturated vapor state (dew-point pressure) and in a saturated liquid state (bubble-point pressure). The target is such correlation as has as simple a function form as possible and is able to estimate even near the critical point where it used to be difficult to estimate. The pressure difference between measured values of the dew- and bubble-point pressure and values calculated from Raoult's law showing an ideal mixture of fluid is expressed by a simple function form of reduced temperature Tr and molar fraction. Tr is thermodynamic temperature/critical temperature. Reproducibility of this correlation is less than {plus minus}3% of the pressure deviation. Concerning also the arbitary composition range and near the critical point, the dew- and bubble-point pressure can be calculated accurately. 24 refs., 4 figs., 5 tabs.

Permeability measurement of some barrier materials as a function of temperature and pressure

International Nuclear Information System (INIS)

Maqsood, M.; Faisal, S.; Ali, J.; Usman, A.; Alamgir, K.; Farooq, K.

2011-01-01

Barrier materials possess the ability to restrict the passage of gases, vapors, and organic liquids through their boundaries. These barrier materials have large number of applications in industry and scientific research. To measure the permeability of barrier materials, a specific gas flow system has been developed, pure helium gas is used to measure the back ground reading through SS-316. The permeability and break-through time has been measured through Inconel X-750, NBR and Viton below and above the atmospheric pressure and at different temperatures 20 deg. C, 40 deg. C and 70 deg. C. (author)

An exposure system for measuring nasal and lung uptake of vapors in rats

Energy Technology Data Exchange (ETDEWEB)

Dahl, A.R.; Brookins, L.K.; Gerde, P. [National Inst. for Working Life, Solna (Sweden)

1995-12-01

Inhaled gases and vapors often produce biological damage in the nasal cavity and lower respiratory tract. The specific site within the respirator tract at which a gas or vapor is absorbed strongly influences the tissues at risk to potential toxic effects; to predict or to explain tissue or cell specific toxicity of inhaled gases or vapors, the sites at which they are absorbed must be known. The purpose of the work reported here was to develop a system for determining nose and lung absorption of vapors in rats, an animal commonly used in inhalation toxicity studies. In summary, the exposure system described allows us to measure in the rate: (1) nasal absorption and desorption of vapors; (2) net lung uptake of vapors; and (3) the effects of changed breathing parameters on vapor uptake.

Line pressure effects on differential pressure measurements

International Nuclear Information System (INIS)

Neff, G.G.; Evans, R.P.

1982-01-01

The performance of differential pressure transducers in experimental pressurized water reactor (PWR) systems was evaluated. Transient differential pressure measurements made using a simple calibration proportionality relating differential pressure to output voltage could have large measurement uncertainties. A more sophisticated calibration equation was derived to incorporate the effects of zero shifts and sensitivity shifts as pressure in the pressure sensing line changes with time. A comparison made between the original calibration proportionality equation and the derived compensation equation indicates that potential measurement uncertainties can be reduced

Deflagration explosion of an unconfined fuel vapor cloud

International Nuclear Information System (INIS)

Taki, S.; Ogawa, Y.

1981-01-01

In the reported study, explosions are produced by injecting a small amount of liquefied petroleum gas (LPG) into air. The ignition and subsequent evolution of the explosion of the unconfined vapor cloud are observed by the simultaneous use of direct photographs and pressure recording. The intensity of the compression waves generated by unconfined combustion are modeled on the basis of the solution of the conservation equations for the flow associated with a spherically symmetric expanding piston. The obtained results are compared with the measurements. It is pointed out that the development of unconfined fuel vapor cloud explosions can be divided into two stages, including a deflagration propagating in premixed gases, which is followed by a diffusion flame promoted by buoyancy and convection. The experimental result from the pressure measurement is found to be quantitatively consistent with the result obtained from the spherical piston model

Ellipsometry-based combination of isothermal sorption-desorption measurement and temperature programmed desorption technique: A probe for interaction of thin polymer films with solvent vapor

Science.gov (United States)

Efremov, Mikhail Yu.; Nealey, Paul F.

2018-05-01

An environmental chamber equipped with an in situ spectroscopic ellipsometer, programmatic vapor pressure control, and variable temperature substrate holder has been designed for studying polymer coating behavior during an exposure to a solvent vapor and also for probing the residual solvent in the film afterwards. Both sorption-desorption cycle at a constant temperature and temperature programmed desorption (TPD) of the residual solvent manifest themselves as a change of the film thickness. Monitoring of ellipsometric angles of the coating allows us to determine the thickness as a function of the vapor pressure or sample temperature. The solvent vapor pressure is precisely regulated by a computer-controlled pneumatics. TPD spectra are recorded during heating of the film in an oil-free vacuum. The vapor pressure control system is described in detail. The system has been tested on 6-170 nm thick polystyrene, poly(methyl methacrylate), and poly(2-vinyl pyridine) films deposited on silicon substrates. Liquid toluene, water, ethanol, isopropanol, cyclohexane, 1,2-dichloroethane, and chlorobenzene were used to create a vapor atmosphere. Typical sorption-desorption and TPD curves are shown. The instrument achieves sub-monolayer sensitivity for adsorption studies on flat surfaces. Polymer-solvent vapor systems with strong interaction demonstrate characteristic absorption-desorption hysteresis spanning from vacuum to the glass transition pressure. Features on the TPD curves can be classified as either glass transition related film contraction or low temperature broad contraction peak. Typical absorption-desorption and TPD dependencies recorded for the 6 nm thick polystyrene film demonstrate the possibility to apply the presented technique for probing size effects in extremely thin coatings.

Water vapor pressure over molten KH2PO4 and demonstration of water electrolysis at ∼300ºC

DEFF Research Database (Denmark)

Berg, Rolf W.; Nikiforov, Aleksey Valerievich; Petrushina, Irina

2016-01-01

A new potentially high-efficiency electrolyte for water electrolysis: molten monobasic potassium phosphate, KH2PO4 or KDP has been investigated at temperatures ∼275–325 °C. At these temperatures, KH2PO4 was found to dissociate into H2O gas in equilibrium with a melt mixture of KH2PO4—K2H2P2O7—KPO3...... of water and methane or hydrogen to be 0.40 ± 0.02 or 1.2 ± 0.03. At equilibrium the vapor pressure was much lower than the vapor pressure above liquid water at the same temperature. Electrolysis was realized by passing current through closed ampoules (vacuum sealed quartz glass electrolysis cells...... with platinum electrodes and the electrolyte melt). The formation of mixtures of hydrogen and oxygen gases as well as the water vapor was detected by Raman spectroscopy. In this way it was demonstrated that water is present in the new electrolyte: molten KH2PO4 can be split by electrolysis via the reaction 2H2O...

Highly Efficient 2D/3D Hybrid Perovskite Solar Cells via Low-Pressure Vapor-Assisted Solution Process.

Science.gov (United States)

Li, Ming-Hsien; Yeh, Hung-Hsiang; Chiang, Yu-Hsien; Jeng, U-Ser; Su, Chun-Jen; Shiu, Hung-Wei; Hsu, Yao-Jane; Kosugi, Nobuhiro; Ohigashi, Takuji; Chen, Yu-An; Shen, Po-Shen; Chen, Peter; Guo, Tzung-Fang

2018-06-08

The fabrication of multidimensional organometallic halide perovskite via a low-pressure vapor-assisted solution process is demonstrated for the first time. Phenyl ethyl-ammonium iodide (PEAI)-doped lead iodide (PbI 2 ) is first spin-coated onto the substrate and subsequently reacts with methyl-ammonium iodide (MAI) vapor in a low-pressure heating oven. The doping ratio of PEAI in MAI-vapor-treated perovskite has significant impact on the crystalline structure, surface morphology, grain size, UV-vis absorption and photoluminescence spectra, and the resultant device performance. Multiple photoluminescence spectra are observed in the perovskite film starting with high PEAI/PbI 2 ratio, which suggests the coexistence of low-dimensional perovskite (PEA 2 MA n -1 Pb n I 3 n +1 ) with various values of n after vapor reaction. The dimensionality of the as-fabricated perovskite film reveals an evolution from 2D, hybrid 2D/3D to 3D structure when the doping level of PEAI/PbI 2 ratio varies from 2 to 0. Scanning electron microscopy images and Kelvin probe force microscopy mapping show that the PEAI-containing perovskite grain is presumably formed around the MAPbI 3 perovskite grain to benefit MAPbI 3 grain growth. The device employing perovskite with PEAI/PbI 2 = 0.05 achieves a champion power conversion efficiency of 19.10% with an open-circuit voltage of 1.08 V, a current density of 21.91 mA cm -2 , and a remarkable fill factor of 80.36%. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Normal coordinate treatment of liquid water and calculation of vapor pressure isotope effects

International Nuclear Information System (INIS)

Gellai, B.; Van Hook, W.A.

1983-01-01

A vibrational analysis of liquid water is reported, assuming a completely hydrogen-bonded network with continuously varying strengths of the hydrogen bonds. Frequency distribution calculations are made for intramolecular stretching and bending modes and for the intramolecular frequency region. The calculated distributions are compared with the experimental spectroscopic ones. As another test, vapor pressure isotope effects are calculated from the theoretical distributions for some isotopic water molecules. Results are compared with those of other authors obtained from a mixture model. (author)

Pressure Measurement Systems

Science.gov (United States)

1990-01-01

System 8400 is an advanced system for measurement of gas and liquid pressure, along with a variety of other parameters, including voltage, frequency and digital inputs. System 8400 offers exceptionally high speed data acquisition through parallel processing, and its modular design allows expansion from a relatively inexpensive entry level system by the addition of modular Input Units that can be installed or removed in minutes. Douglas Juanarena was on the team of engineers that developed a new technology known as ESP (electronically scanned pressure). The Langley ESP measurement system was based on miniature integrated circuit pressure-sensing transducers that communicated pressure information to a minicomputer. In 1977, Juanarena formed PSI to exploit the NASA technology. In 1978 he left Langley, obtained a NASA license for the technology, introduced the first commercial product, the 780B pressure measurement system. PSI developed a pressure scanner for automation of industrial processes. Now in its second design generation, the DPT-6400 is capable of making 2,000 measurements a second and has 64 channels by addition of slave units. New system 8400 represents PSI's bid to further exploit the 600 million U.S. industrial pressure measurement market. It is geared to provide a turnkey solution to physical measurement.

Vapor pressure of heat transfer fluids of absorption refrigeration machines and heat pumps: Binary solutions of lithium nitrate with methanol

Energy Technology Data Exchange (ETDEWEB)

Safarov, Javid T. [Heat and Refrigeration Techniques, Azerbaijan Technical University, Huseyn Javid Avn. 25, AZ1073 Baku (Azerbaijan)]. E-mail: javids@azdata.net

2005-12-15

Vapor pressure p of LiNO{sub 3} + CH{sub 3}OH solutions at T = (298.15 to 323.15) K was reported, osmotic {phi} and activity coefficients {gamma}; and activity of solvent a {sub s} have been evaluated. The experiments were carried out in molality range m = (0.18032 to 5.2369) mol . kg{sup -1}. The Antoine equation was used for the empiric description of experimental vapor pressure results. The Pitzer-Mayorga model with inclusion of Archer's ionic strength dependence of the third virial coefficient was used for the description of calculated osmotic coefficients. The parameters of Archer extended Pitzer model were used for evaluation of activity coefficients.

Note: implementation of a cold spot setup for controlled variation of vapor pressures and its application to an InBr containing discharge lamp.

Science.gov (United States)

Briefi, S

2013-02-01

In order to allow for a systematic investigation of the plasma properties of discharges containing indium halides, which are proposed as an efficient alternative for mercury based low pressure discharge lamps, a controlled variation of the indium halide density is mandatory. This can be achieved by applying a newly designed setup in which a well-defined cold spot location is implemented and the cold spot temperature can be adjusted between 50 and 350 °C without influencing the gas temperature. The performance of the setup has been proved by comparing the calculated evaporated InBr density (using the vapor pressure curve) with the one measured via white light absorption spectroscopy.

Retrieval of water vapor mixing ratios from a laser-based sensor

Science.gov (United States)

Tucker, George F.

1995-01-01

Langley Research Center has developed a novel external path sensor which monitors water vapor along an optical path between an airplane window and reflective material on the plane's engine. An infrared tunable diode laser is wavelength modulated across a water vapor absorption line at a frequency f. The 2f and DC signals are measured by a detector mounted adjacent to the laser. The 2f/DC ratio depends on the amount of wavelength modulation, the water vapor absorption line being observed, and the temperature, pressure, and water vapor content of the atmosphere. The present work concerns efforts to quantify the contributions of these factors and to derive a method for extracting the water vapor mixing ratio from the measurements. A 3 m cell was fabricated in order to perform laboratory tests of the sensor. Measurements of 2f/DC were made for a series of pressures and modulation amplitudes. During my 1994 faculty fellowship, a computer program was created which allowed 2f/DC to be calculated for any combination of the variables which effect it. This code was used to generate 2f/DC values for the conditions measured in the laboratory. The experimental and theoretical values agreed to within a few percent. As a result, the laser modulation amplitude can now be set in the field by comparing the response of the instrument to the calculated response as a function of modulation amplitude. Once the validity of the computer code was established, it was used to investigate possible candidate absorption lines. 2f/DC values were calculated for pressures, temperatures, and water vapor mixing ratios expected to be encountered in future missions. The results have been incorporated into a database which will be used to select the best line for a particular mission. The database will also be used to select a retrieval technique. For examples under some circumstances there is little temperature dependence in 2f/DC so temperature can be neglected. In other cases, there is a dependence

Methods for calculation of engineering parameters for gas separation. [vapor pressure and solubility of gases in organic liquids

Science.gov (United States)

Lawson, D. D.

1979-01-01

A group additivity method is generated which allows estimation, from the structural formulas alone, of the energy of vaporization and the molar volume at 25 C of many nonpolar organic liquids. Using these two parameters and appropriate thermodynamic relations, the vapor pressure of the liquid phase and the solubility of various gases in nonpolar organic liquids are predicted. It is also possible to use the data to evaluate organic and some inorganic liquids for use in gas separation stages or liquids as heat exchange fluids in prospective thermochemical cycles for hydrogen production.

Analysis of organic vapors with laser induced breakdown spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Nozari, Hadi; Tavassoli, Seyed Hassan [Laser and Plasma Research Institute, Shahid Beheshti University, G. C, 1983963113 Evin, Tehran (Iran, Islamic Republic of); Rezaei, Fatemeh, E-mail: fatemehrezaei@kntu.ac.ir [Department of Physics, K. N. Toosi University of Technology, 15875-4416 Shariati, Tehran (Iran, Islamic Republic of)

2015-09-15

In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane vapors. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic vapors that are mixed with air inside a quartz chamber at atmospheric pressure. The plasma is generated with focused, Q-switched Nd:YAG radiation at the wavelength of 1064 nm. The effects of ignition and vapor pressure are discussed in view of the appearance of the emission spectra. The recorded spectra are proportional to the vapor pressure in air. The hydrogen and oxygen contributions diminish gradually with consecutive laser-plasma events without gas flow. The results show that LIBS can be used to characterize organic vapor.

Analysis of organic vapors with laser induced breakdown spectroscopy

International Nuclear Information System (INIS)

Nozari, Hadi; Tavassoli, Seyed Hassan; Rezaei, Fatemeh

2015-01-01

In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane vapors. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic vapors that are mixed with air inside a quartz chamber at atmospheric pressure. The plasma is generated with focused, Q-switched Nd:YAG radiation at the wavelength of 1064 nm. The effects of ignition and vapor pressure are discussed in view of the appearance of the emission spectra. The recorded spectra are proportional to the vapor pressure in air. The hydrogen and oxygen contributions diminish gradually with consecutive laser-plasma events without gas flow. The results show that LIBS can be used to characterize organic vapor

Correlation of chemical evaporation rate with vapor pressure.

Science.gov (United States)

Mackay, Donald; van Wesenbeeck, Ian

2014-09-02

A new one-parameter correlation is developed for the evaporation rate (ER) of chemicals as a function of molar mass (M) and vapor pressure (P) that is simpler than existing correlations. It applies only to liquid surfaces that are unaffected by the underlying solid substrate as occurs in the standard ASTM evaporation rate test and to quiescent liquid pools. The relationship has a sounder theoretical basis than previous correlations because ER is correctly correlated with PM rather than P alone. The inclusion of M increases the slope of previous log ER versus log P regressions to a value close to 1.0 and yields a simpler one-parameter correlation, namely, ER (μg m(-1) h(-1)) = 1464P (Pa) × M (g mol(-1)). Applications are discussed for the screening level assessment and ranking of chemicals for evaporation rate, such as pesticides, fumigants, and hydrocarbon carrier fluids used in pesticide formulations, liquid consumer products used indoors, and accidental spills of liquids. The mechanistic significance of the single parameter as a mass-transfer coefficient or velocity is discussed.

Water-vapor absorption line measurements in the 940-nm band by using a Raman-shifted dye laser

Science.gov (United States)

Chu, Zhiping; Wilkerson, Thomas D.; Singh, Upendra N.

1993-01-01

We report water-vapor absorption line measurements that are made by using the first Stokes radiation (930-982 nm) with HWHM 0.015/cm generated by a narrow-linewidth, tunable dye laser. Forty-five absorption line strengths are measured with an uncertainty of 6 percent and among them are fourteen strong lines that are compared with previous measurements for the assessment of spectral purity of the light source. Thirty air-broadened linewidths are measured with 8 percent uncertainty at ambient atmospheric pressure with an average of 0.101/cm. The lines are selected for the purpose of temperature-sensitive or temperature-insensitive lidar measurements. Results for these line strengths and linewidths are corrected for broadband radiation and finite laser linewidth broadening effects and compared with the high-resolution transmission molecular absorption.

GOZCARDS Merged Data for Water Vapor Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

Data.gov (United States)

National Aeronautics and Space Administration — The GOZCARDS Merged Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozMmlpH2O) contains zonal means and related...

Pressure suppressing device

International Nuclear Information System (INIS)

Naito, Makoto.

1980-01-01

Purpose: To prevent the pressure in the reactor container from excessively increasing even when vapor leaks from the dry well to a space of the suppression chamber, without passing though the suppression pool at the time of loss of coolant accident. Constitution: When vapor of a high temperature and a high pressure at the time of loss of coolant accident flows from the dry well to the suppression chamber without passing through suppression pool water, vapor dose not condense with pool water, and therefore the pressure within the chamber abnormally increases. For this reason, this abnormal pressure is detected by a pressure detector thereby to start the operations of a blower and a pump. By starting the blower, the pressure in the dry well becomes lower than the pressure in the chamber, and vapor entirely passes through the pool water and entirely condenses with the pool water. By starting the pump, the pool water is sprayed over the space of the chamber, and vapor in the space is condensed. (Yoshino, Y.)

Measurement of atmospheric precipitable water using a solar radiometer. [water vapor absorption effects

Science.gov (United States)

Pitts, D. E.; Dillinger, A. E.; Mcallum, W. E.

1974-01-01

A technique is described and tested that allows the determination of atmospheric precipitable water from two measurements of solar intensity: one in a water-vapor absorption band and another in a nearby spectral region unaffected by water vapor.

Vapor pressure and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures

Science.gov (United States)

Bolgar, A. S.; Verkhoglyadova, T. S.; Samsonov, G. V.

1985-01-01

The vapor pressure and evaporation rate of borides of titanium, zirconium, and chrome; and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide; and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum.

Oscillometric blood pressure measurements: differences between measured and calculated mean arterial pressure.

NARCIS (Netherlands)

Kiers, H.D.; Hofstra, J.M.; Wetzels, J.F.M.

2008-01-01

Mean arterial pressure (MAP) is often used as an index of overall blood pressure. In recent years, the use of automated oscillometric blood pressure measurement devices is increasing. These devices directly measure and display MAP; however, MAP is often calculated from systolic blood pressure (SBP)

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

Science.gov (United States)

Makarieva, A. M.; Gorshkov, V. G.; Sheil, D.; Nobre, A. D.; Li, B.-L.

2013-01-01

Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power - this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

Radiation-use efficiency response to vapor pressure deficit for maize and sorghum

International Nuclear Information System (INIS)

Kiniry, J.R.; Landivar, J.A.; Witt, M.; Gerik, T.J.; Cavero, J.; Wade, L.J.

1998-01-01

Variability within a crop species in the amount of dry mass produced per unit intercepted solar radiation, or radiation-use efficiency (RUE), is important for the quantification of plant productivity. RUE has been used to integrate (1) leaf area, (2) solar radiation interception, and (3) productivity per unit leaf area into crop productivity. Responsiveness of RUE to vapor pressure deficit (VPD) should relate closely to responsiveness of CO 2 exchange rate (CER) to VPD. The objective of this study was to compare independent RUE measurements to published response functions relating VPD with RUE of maize (Zea mays L.) and grain sorghum [Sorghum bicolor L. (Moench)]. Data sets from five locations covering a wide range of mean VPD values were compared to published response functions. Predicted RUE values were nearly always within the 95% confidence intervals of measurements. Measured RUE of maize decreased as VPD increased from 0.9 to 1.7 kPa. For sorghum, measured values of RUE agreed closely with predictions. RUE of sorghum decreased as VPD increased from 1.1 to 2.2 kPa. The relative RUE:VPD responses for these two species were similar to CER:VPD responses reported in the literature. Thus, these RUE:VPD responses may be general and appear to be related to carbon exchange rates. We calculated the expected impacts of VPD on RUE at three USA locations during maize and sorghum growing seasons. The RUE:VPD equations offer hope in describing location effects and time-of-year effects on RUE. (author)

Experimental study of arsenic speciation in vapor phase to 500°C: Implications for As transport and fractionation in low-density crustal fluids and volcanic gases.

OpenAIRE

Pokrovski , Gleb S.; Zakirov , Ildar V.; Roux , Jacques; Testemale , Denis; Hazemann , Jean-Louis; Y. U. Bychkov , Andrew; V. Golikova , Galina

2002-01-01

The stoichiometry and stability of arsenic gaseous complexes were determined in the system As-H2O ± NaCl ± HCl ± H2S at temperatures up to 500°C and pressures up to 600 bar, from both measurements of As(III) and As(V) vapor-liquid and vapor-solid partitioning, and X-ray absorption fine structure (XAFS) spectroscopic study of As(III)-bearing aqueous fluids. Vapor-aqueous solution partitioning for As(III) was measured from 250 to 450°C at the saturated vapor pressure of the system (Psat) with a...

High Pressure Vapor-Liquid Equilibrium of Supercritical Carbon Dioxide + n-Hexane System

Institute of Scientific and Technical Information of China (English)

YU Jinglin; TIAN Yiling; ZHU Rongjiao; LIU Zhihua

2006-01-01

Vapor-liquid equilibrium data of supercritical carbon dioxide + n-hexane system were measured at 313.15 K,333.15 K,353.15 K,and 373.15 K and their molar volumes and densities were measured both in the subcritical and supercritical regions ranging from 2.15 to 12.63 MPa using a variable-volume autoclave.The thermodynamic properties including mole fractions,densities,and molar volumes of the system were calculated with an equation of state by Heilig and Franck,in which a repulsion term and a square-well potential attraction term for intermolecular interaction was used.The pairwise combination rule was used to calculate the square-well molecular interaction potential and three adjustable parameters (ω,kε,kσ) were obtained.The Heilig-Franck equation of state is found to have good correlation with binary vapor-liquid equilibrium data of the carbon dioxide + n-hexane system.

Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits.

Science.gov (United States)

Gong, Chunmei; Wang, Jiajia; Hu, Congxia; Wang, Junhui; Ning, Pengbo; Bai, Juan

2015-08-01

C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C4 species, regarding the interactive effects of drought stress and different leaf-air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C4 photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO2 assimilation rate (An) was enhanced as vapor pressure deficits increased. A close relationship between An and stomatal conductance (gs) suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C4 enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4 biochemical pathways were present in H. scoparium to respond to environmental challenges. Copyright © 2015. Published by Elsevier B.V.

Effect of vapor-phase oxygen on chemical vapor deposition growth of graphene

Science.gov (United States)

Terasawa, Tomo-o.; Saiki, Koichiro

2015-03-01

To obtain a large-area single-crystal graphene, chemical vapor deposition (CVD) growth on Cu is considered the most promising. Recently, the surface oxygen on Cu has been found to suppress the nucleation of graphene. However, the effect of oxygen in the vapor phase was not elucidated sufficiently. Here, we investigate the effect of O2 partial pressure (PO2) on the CVD growth of graphene using radiation-mode optical microscopy. The nucleation density of graphene decreases monotonically with PO2, while its growth rate reaches a maximum at a certain pressure. Our results indicate that PO2 is an important parameter to optimize in the CVD growth of graphene.

Modeling and control of diffusion and low-pressure chemical vapor deposition furnaces

Science.gov (United States)

De Waard, H.; De Koning, W. L.

1990-03-01

In this paper a study is made of the heat transfer inside cylindrical resistance diffusion and low-pressure chemical vapor deposition furnaces, aimed at developing an improved temperature controller. A model of the thermal behavior is derived which also covers the important class of furnaces equipped with semitransparent quartz process tubes. The model takes into account the thermal behavior of the thermocouples. It is shown that currently used temperature controllers are highly inefficient for very large scale integration applications. Based on the model an alternative temperature controller of the linear-quadratic-Gaussian type is proposed which features direct wafer temperature control. Some simulation results are given.

Dew point fast measurement in organic vapor mixtures using quartz resonant sensor

Science.gov (United States)

Nie, Jing; Liu, Jia; Meng, Xiaofeng

2017-01-01

A fast dew point sensor has been developed for organic vapor mixtures by using the quartz crystal with sensitive circuits. The sensor consists of the quartz crystal and a cooler device. Proactive approach is taken to produce condensation on the surface of the quartz crystal, and it will lead to a change in electrical features of the quartz crystal. The cessation of oscillation was measured because this phenomenon is caused by dew condensation. Such a phenomenon can be used to detect the dew point. This method exploits the high sensitivity of the quartz crystal but without frequency measurement and also retains the stability of the resonant circuit. It is strongly anti-interfered. Its performance was evaluated with acetone-methanol mixtures under different pressures. The results were compared with the dew points predicted from the universal quasi-chemical equation to evaluate the performance of the proposed sensor. Though the maximum deviations of the sensor are less than 1.1 °C, it still has a fast response time with a recovery time of less than 10 s, providing an excellent dehumidifying performance.

Long Term Measurement of the Vapor Pressure of Gold in the Au-C System

Science.gov (United States)

Copland, Evan H.

2009-01-01

Incorporating the {Au(s,l) + graphite} reference in component activity measurements made with the multiple effusion-cell vapor source mass spectrometry (multicell KEMS) technique provides a fixed temperature defining ITS-90 (T(sub mp)(Au) = 1337.33K) and a systematic method to check accuracy. Over a 2 year period delta H sub(298)Au was determined by the 2nd and 3rd law methods in 25 separate experiments and were in the ranges 362.2 plus or minus 3.3 kJmol(sup -1) and 367.8 plus or minus 1.1 kJmol(sup -1), respectively. This 5 kJmol-1 discrepancy is transferred directly to the measured activities. This is unacceptable and the source of this discrepancy needs to be understood and corrected. Accepting the 2nd law value increases p(Au) by about 50 percent, brings the 2nd and 3rd law values into agreement and removes the T dependence in the 3rd law values. While compelling, there is no way to independently determine instrument sensitivities, S(sub Au), with T in a single experiment with KEMS. This lack of capability is stopping a deeper understanding of this problem. In addition, the Au-C phase diagram suggests a eutectic invariant reaction: L-Au(4.7at%C) = FCC-Au(0.08at%C) + C(graphite) at T(sub e) approximately 1323K. This high C concentration in Au(l) must reduce p(Au) in equilibrium with {Au(s,l) + graphite} and raises some critical questions about the Gibbs free energy functions of Au(s,l) and the Au fixed point (T(sub mp)(Au) = 1337.33K) which is always measured in graphite.

Modeling vapor liquid equilibrium of ionic liquids + gas binary systems at high pressure with cubic equations of state

Directory of Open Access Journals (Sweden)

A. C. D. Freitas

2013-03-01

Full Text Available Ionic liquids (IL have been described as novel environmentally benign solvents because of their remarkable characteristics. Numerous applications of these solvents continue to grow at an exponential rate. In this work, high pressure vapor liquid equilibria for 17 different IL + gas binary systems were modeled at different temperatures with Peng-Robinson (PR and Soave-Redlich-Kwong (SRK equations of state, combined with the van der Waals mixing rule with two binary interaction parameters (vdW-2. The experimental data were taken from the literature. The optimum binary interaction parameters were estimated by minimization of an objective function based on the average absolute relative deviation of liquid and vapor phases, using the modified Simplex algorithm. The solubilities of all gases studied in this work decrease as the temperature increases and increase with increasing pressure. The correlated results were highly satisfactory, with average absolute relative deviations of 2.10% and 2.25% for PR-vdW-2 and SRK-vdW-2, respectively.

LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Saharan Air Layers and Tropical Disturbances

Science.gov (United States)

Ismail, Syed; Ferrare, Richard A.; Browell, Edward V.; Kooi, Susan A.; Dunion, Jason P.; Heymsfield, Gerry; Notari, Anthony; Butler, Carolyn F.; Burton, Sharon; Fenn, Marta;

A Two-Line Absorption Instrument for Scramjet Temperature and Water Vapor Concentration Measurement in HYPULSE

Science.gov (United States)

Tsai, C. Y.

1998-01-01

A three beam water vapor sensor system has been modified to provide for near simultaneous temperature measurement. The system employs a tunable diode laser to scan spectral line of water vapor. The application to measurements in a scramjet combustor environment of a shock tunnel facility is discussed. This report presents and discusses die initial calibration of the measurement system.

Differential absorption and Raman lidar for water vapor profile measurements - A review

Science.gov (United States)

Grant, William B.

1991-01-01

Differential absorption lidar and Raman lidar have been applied to the range-resolved measurements of water vapor density for more than 20 years. Results have been obtained using both lidar techniques that have led to improved understanding of water vapor distributions in the atmosphere. This paper reviews the theory of the measurements, including the sources of systematic and random error; the progress in lidar technology and techniques during that period, including a brief look at some of the lidar systems in development or proposed; and the steps being taken to improve such lidar systems.

Emerging Technologies and Synergies for Airborne and Space-Based Measurements of Water Vapor Profiles

Science.gov (United States)

Nehrir, Amin R.; Kiemle, Christoph; Lebsock, Mathew D.; Kirchengast, Gottfried; Buehler, Stefan A.; Löhnert, Ulrich; Liu, Cong-Liang; Hargrave, Peter C.; Barrera-Verdejo, Maria; Winker, David M.

2017-11-01

A deeper understanding of how clouds will respond to a warming climate is one of the outstanding challenges in climate science. Uncertainties in the response of clouds, and particularly shallow clouds, have been identified as the dominant source of the discrepancy in model estimates of equilibrium climate sensitivity. As the community gains a deeper understanding of the many processes involved, there is a growing appreciation of the critical role played by fluctuations in water vapor and the coupling of water vapor and atmospheric circulations. Reduction of uncertainties in cloud-climate feedbacks and convection initiation as well as improved understanding of processes governing these effects will result from profiling of water vapor in the lower troposphere with improved accuracy and vertical resolution compared to existing airborne and space-based measurements. This paper highlights new technologies and improved measurement approaches for measuring lower tropospheric water vapor and their expected added value to current observations. Those include differential absorption lidar and radar, microwave occultation between low-Earth orbiters, and hyperspectral microwave remote sensing. Each methodology is briefly explained, and measurement capabilities as well as the current technological readiness for aircraft and satellite implementation are specified. Potential synergies between the technologies are discussed, actual examples hereof are given, and future perspectives are explored. Based on technical maturity and the foreseen near-mid-term development path of the various discussed measurement approaches, we find that improved measurements of water vapor throughout the troposphere would greatly benefit from the combination of differential absorption lidar focusing on the lower troposphere with passive remote sensors constraining the upper-tropospheric humidity.

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

Science.gov (United States)

Jagoe, Christopher; Schwartz, Jacob; Goldston, Robert

2016-10-01

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

Calibration of Raman lidar water vapor profiles by means of AERONET photometer observations and GDAS meteorological data

Science.gov (United States)

Dai, Guangyao; Althausen, Dietrich; Hofer, Julian; Engelmann, Ronny; Seifert, Patric; Bühl, Johannes; Mamouri, Rodanthi-Elisavet; Wu, Songhua; Ansmann, Albert

2018-05-01

We present a practical method to continuously calibrate Raman lidar observations of water vapor mixing ratio profiles. The water vapor profile measured with the multiwavelength polarization Raman lidar class="text">PollyXT is calibrated by means of co-located AErosol RObotic NETwork (AERONET) sun photometer observations and Global Data Assimilation System (GDAS) temperature and pressure profiles. This method is applied to lidar observations conducted during the Cyprus Cloud Aerosol and Rain Experiment (CyCARE) in Limassol, Cyprus. We use the GDAS temperature and pressure profiles to retrieve the water vapor density. In the next step, the precipitable water vapor from the lidar observations is used for the calibration of the lidar measurements with the sun photometer measurements. The retrieved calibrated water vapor mixing ratio from the lidar measurements has a relative uncertainty of 11 % in which the error is mainly caused by the error of the sun photometer measurements. During CyCARE, nine measurement cases with cloud-free and stable meteorological conditions are selected to calculate the precipitable water vapor from the lidar and the sun photometer observations. The ratio of these two precipitable water vapor values yields the water vapor calibration constant. The calibration constant for the class="text">PollyXT Raman lidar is 6.56 g kg-1 ± 0.72 g kg-1 (with a statistical uncertainty of 0.08 g kg-1 and an instrumental uncertainty of 0.72 g kg-1). To check the quality of the water vapor calibration, the water vapor mixing ratio profiles from the simultaneous nighttime observations with Raman lidar and Vaisala radiosonde sounding are compared. The correlation of the water vapor mixing ratios from these two instruments is determined by using all of the 19 simultaneous nighttime measurements during CyCARE. Excellent agreement with the slope of 1.01 and the R2 of 0.99 is found. One example is presented to demonstrate the full potential of a well-calibrated Raman

In-situ epitaxial growth of heavily phosphorus doped SiGe by low pressure chemical vapor deposition

CERN Document Server

Lee, C J

1998-01-01

We have studied epitaxial crystal growth of Si sub 1 sub - sub x Ge sub x films on silicon substrates at 550 .deg. C by low pressure chemical vapor deposition. In a low PH sub 3 partial pressure region such as below 1.25x10 sup - sup 3 Pa, both the phosphorus and carrier concentrations increased with increasing PH sub 3 partial pressure, but the deposition rate and the Ge fraction remained constant. In a higher PH sub 3 partial pressure region, the deposition rate, the phosphorus concentration, and the carrier concentration decreased, while the Ge fraction increased. These suggest that high surface coverage of phosphorus suppresses both SiH sub 4 and GeH sub 4 adsorption/reactions on the surfaces, and its suppression effect on SiH sub 4 is actually much stronger than on GeH sub 4. In particular, epitaxial crystal growth is largely controlled by surface coverage effect of phosphorus in a higher PH sub 3 partial pressure region.

A Local Propagation for Vapor Explosions

International Nuclear Information System (INIS)

Ochiai, M.; Bankoff, S.G.

1976-01-01

Explosive boiling, defined as energy transfer leading to formation of vapor rapidly enough to produce large shock waves, has been widely studied in a number of contexts. Depending upon the nature and temperatures of the liquids and mode of contacting, large-scale mixing and explosive vaporization may occur, or alternatively, only relatively non-energetic, film-type boiling may exist. The key difference is whether a mechanism is operative for increasing the liquid-liquid interfacial area in a time scale consistent with the formation of a detonation wave. Small drops of a cold volatile liquid were dropped onto a free surface of a hot, non-volatile liquid. The critical Weber number for coalescence is obtained from the envelope of the film boiling region. Markedly different behavior for the two hot liquids is observed. A 'splash' theory for local propagation of vapor explosions in spontaneously nucleating liquid-liquid systems is now formulated. After a random contact is made, explosive growth and coalescence of the vapor bubbles occurs as soon as the surrounding pressure is relieved, resulting in a high-pressure vapor layer at the liquid-liquid contact area. This amounts to an impact pressure applied to the free surface, with a resulting velocity distribution obtained from potential flow theory. The peak pressure predictions are. consistent with data for Freon-oil mixing, but further evaluation will await additional experimental data. Nevertheless, the current inference is that a UO 2 -Na vapor explosion in a reactor environment cannot be visualized. In conclusion: The propagation model presented here differs in some details from that of Henry and Fauske, although both are consistent with some peak pressure data obtained by Henry, et al. Clearly, additional experimental information is needed for further evaluation of these theories. Nevertheless, it should be emphasized that even at this time a number of important observations concerning the requirements for a vapor

Comparative X-ray photoelectron spectroscopy study of plasma enhanced chemical vapor deposition and micro pressure chemical vapor deposition of phosphorus silicate glass layers after rapid thermal annealing

International Nuclear Information System (INIS)

Beshkov, G.; Krastev, V.; Gogova, D.; Talik, E.; Adamies, M.

2008-01-01

In this paper the bonding state of Phosphorus Silicate Glass (PSG) layers obtained by two different technological approaches, i.e. in two types of reactors: Plasma Enhanced Chemical Vapor Deposition (PECVD) and Micro Pressure Chemical Vapor Deposition (MPCVD) are investigated employing XPS and AES. The PSG layers are deposited at 380 0 C and 420 0 C in corresponding reactors. XPS and AES analyses show that Si2p peak recorded from PECVD layers are not as expected at their position characteristics of silicon dioxide but instead they are at the characteristic of elemental silicon. Plasma enhancement during deposition leads to less oxidized and more inhomogeneous layer. After rapid thermal annealing the Si2p peak is situated at position characteristic of silicon dioxide. (authors)

SPADE H2O measurements and the seasonal cycle of statospheric water vapor

Science.gov (United States)

Hintsa, Eric J.; Weinstock, Elliot M.; Dessler, Andrew E.; Anderson, James G.; Loewenstein, Max; Podolske, James R.

1994-01-01

We present measurements of lower statospheric water vapor obtained during the Stratospheric Phototchemistry, Aerosols and Dynamics Expedition (SPADE) mission with a new high precision, fast response, Lyman-alpha hygrometer. The H2O data show a distinct seasonal cycle. For air that recently entered the statosphere, data collected during the fall show much more water vapor than data from the spring. Fast quasi-horizontal mixing causes compact relationships between water and N2O to be established on relatively short time scales. The measurements are consistent with horizontal mixing times of a few months or less. Vertical mixing appears to cause the seasonal variations in water vapor to propagate up to levels corresponding to air that has been in the stratosphere approximately one year.

Computer modeling of the sensitivity of a laser water vapor sensor to variations in temperature and air speed

Science.gov (United States)

Tucker, George F.

1994-01-01

Currently, there is disagreement among existing methods of determining atmospheric water vapor concentration at dew-points below -40 C. A major source of error is wall effects which result from the necessity of bringing samples into the instruments. All of these instruments also have response times on the order of seconds. NASA Langley is developing a water vapor sensor which utilizes the absorption of the infrared radiation produced by a diode laser to estimate water vapor concentration. The laser beam is directed through an aircraft window to a retroreflector located on an engine. The reflected beam is detected by an infrared detector located near the laser. To maximize signal to noise, derivative signals are analyzed. By measuring the 2f/DC signal and correcting for ambient temperature, atmospheric pressure and air speed (which results in a Doppler shifting of the laser beam), the water vapor concentration can be retrieved. Since this is an in situ measurement there are no wall effects and measurements can be made at a rate of more than 20 per second. This allows small spatial variations of water vapor to be studied. In order to study the sensitivity of the instrument to variations in temperature and air speed, a computer program which generated the 2f, 3f, 4f, DC and 2f/DC signals of the instrument as a function of temperature, pressure and air speed was written. This model was used to determine the effect of errors in measurement of the temperature and air speed on the measured water vapor concentration. Future studies will quantify the effect of pressure measurement errors, which are expected to be very small. As a result of these studied, a retrieval algorithm has been formulated, and will be applied to data taken during the PEM-West atmospheric science field mission. Spectroscopic studies of the water vapor line used by the instrument will be used to refine this algorithm. To prepare for these studies, several lasers have been studied to determine their

Effect of Growth Pressure on Epitaxial Graphene Grown on 4H-SiC Substrates by Using Ethene Chemical Vapor Deposition

Directory of Open Access Journals (Sweden)

Shuxian Cai

2015-08-01

Full Text Available The Si(0001 face and C(000-1 face dependences on growth pressure of epitaxial graphene (EG grown on 4H-SiC substrates by ethene chemical vapor deposition (CVD was studied using atomic force microscopy (AFM and micro-Raman spectroscopy (μ-Raman. AFM revealed that EGs on Si-faced substrates had clear stepped morphologies due to surface step bunching. However, This EG formation did not occur on C-faced substrates. It was shown by μ-Raman that the properties of EG on both polar faces were different. EGs on Si-faced substrates were relatively thinner and more uniform than on C-faced substrates at low growth pressure. On the other hand, D band related defects always appeared in EGs on Si-faced substrates, but they did not appear in EG on C-faced substrate at an appropriate growth pressure. This was due to the μ-Raman covering the step edges when measurements were performed on Si-faced substrates. The results of this study are useful for optimized growth of EG on polar surfaces of SiC substrates.

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

Science.gov (United States)

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

2007-09-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Flash vaporization during earthquakes evidenced by gold deposits

Science.gov (United States)

Weatherley, Dion K.; Henley, Richard W.

2013-04-01

Much of the world's known gold has been derived from arrays of quartz veins. The veins formed during periods of mountain building that occurred as long as 3 billion years ago, and were deposited by very large volumes of water that flowed along deep, seismically active faults. The veins formed under fluctuating pressures during earthquakes, but the magnitude of the pressure fluctuations and their influence on mineral deposition is not known. Here we use a simple thermo-mechanical piston model to calculate the drop in fluid pressure experienced by a fluid-filled fault cavity during an earthquake. The geometry of the model is constrained using measurements of typical fault jogs, such as those preserved in the Revenge gold deposit in Western Australia, and other gold deposits around the world. We find that cavity expansion generates extreme reductions in pressure that cause the fluid that is trapped in the jog to expand to a very low-density vapour. Such flash vaporization of the fluid results in the rapid co-deposition of silica with a range of trace elements to form gold-enriched quartz veins. Flash vaporization continues as more fluid flows towards the newly expanded cavity, until the pressure in the cavity eventually recovers to ambient conditions. Multiple earthquakes progressively build economic-grade gold deposits.

The ion mobility spectrometer for high explosive vapor detection

International Nuclear Information System (INIS)

Cohen, M.J.; Stimac, R.M.; Wernlund, R.F.

1984-01-01

The Phemto-Chem /SUP R/ Model 100 Ion Mobility Spectrometer (IMS) operates in air and measures a number of explosive vapors at levels as low as partsper-trillion in seconds. The theory and operation of this instrument is discussed. The IMS inhales the vapor sample in a current of air and generates characteristic ions which are separated by time-of -ion drift in the atmospheric pressure gas. Quantitative results, using a dilution tunnel and standard signal generator with TNT, nitroglycerine, ethylene glycol dinitrate, cyclohexanone, methylamine, octafluoronaphthalene and hexafluorobenzene, are given. Rapid sample treatment with sample concentrations, microprocessor signal readout and chemical identification, offer a realistic opportunity of rapid explosive vapor detection at levels down to 10 -14 parts by volume in air

The functional dependence of canopy conductance on water vapor pressure deficit revisited

NARCIS (Netherlands)

Fuchs, Marcel; Stanghellini, Cecilia

2018-01-01

Current research seeking to relate between ambient water vapor deficit (D) and foliage conductance (gF) derives a canopy conductance (gW) from measured transpiration by inverting the coupled transpiration model to yield gW = m − n ln(D) where m and n are fitting parameters. In contrast, this paper

Conical evaporator and liquid-return wick model for vapor anode, multi-tube AMTEC cells

Science.gov (United States)

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

2000-01-01

A detailed, 2-D thermal-hydraulic model for conical and flat evaporators and the liquid sodium return artery in PX-type AMTEC cells was developed, which predicts incipient dryout at the evaporator wick surface. Results obtained at fixed hot and cold side temperatures showed that the flat evaporator provided a slightly lower vapor pressure, but reached the capillary limit at higher temperature. The loss of performance due to partial recondensation over up to 20% of the wick surface of the deep conical evaporators was offset by the larger surface area available for evaporation, providing a slightly higher vapor pressure. Model results matched the PX-3A cell's experimental data of electrical power output, but the predicted temperature of the cell's conical evaporator was consistently ~50 K above measurements. A preliminary analysis indicated that sodium vapor leakage in the cell (through microcracks in the BASE tubes' walls or brazes) may explain the difference between predicted and measured evaporator temperatures in PX-3A. .

High temperature vaporization/decomposition studies of lanthanide and actinide fluorides

International Nuclear Information System (INIS)

Gibson, J.K.; Haire, R.G.

1987-01-01

Binary fluorides of the lanthanide and actinide elements comprise a fundamental class of compounds. The authors' investigations of their basic high temperature vaporization and/or decomposition behavior are aimed at elucidating more fully the thermal properties of selected tri- and tetrafluorides and extending such investigations to fluorides which have not been studied previously. Depending on the particular system and the specific experimental conditions, the authors' measurements can provide such information as the enthalpy associated with a congruent vaporization process and/or the relative stabilities of fluorides containing a lanthanide/actinide element in different oxidation states. The authors are also studying the congruent vaporization of selected lanthanide trifluorides with particular emphasis on two areas. The first concerns the variation in the enthalpies of sublimation of the trifluorides across the lanthanide series. Although this variation is rather small (δ5 kcal where ΔH/sub subl/ is approximately 100 kcal), it is larger than observed for other lanthanide trihalides and is unusually irregular. To examine this reported variation more closely, they are attempting to measure relative vapor pressures/enthalpies of vaporization by studying mixtures of two or more lanthanide trifluorides by the technique discussed above

Measuring fluid pressure

International Nuclear Information System (INIS)

Lee, A.S.

1978-01-01

A method and apparatus are described for measuring the pressure of a fluid having characteristics that make it unsuitable for connection directly to a pressure gauge. The method is particularly suitable for the periodic measurement of the pressure of a supply of liquid Na to Na-lubricated bearings of pumps for pumping Na from a reservoir to the bearing via a filter, the reservoir being contained in a closed vessel containing an inert blanket gas, such as Ar, above the Na. (UK)

Experimental determination of CCl4 hydrate phase equlibria up to high pressures

NARCIS (Netherlands)

Shariati - Sarabi, A.; Lameris, G.H.; Peters, C.J.

2015-01-01

A number of hydrate phase boundaries of the binary system of tetrachloromethane (CCl4) + water were measured experimentally at several temperatures and from low pressures up to 89.25 MPa. These hydrate phase boundaries included hydrate–ice–vapor, hydrate–liquid CCl4–vapor, hydrate–water–vapor,

Undoped and in-situ B doped GeSn epitaxial growth on Ge by atmospheric pressure-chemical vapor deposition

DEFF Research Database (Denmark)

Vincent, B.; Gencarelli, F.; Bender, H.

2011-01-01

In this letter, we propose an atmospheric pressure-chemical vapor deposition technique to grow metastable GeSn epitaxial layers on Ge. We report the growth of defect free fully strained undoped and in-situ B doped GeSn layers on Ge substrates with Sit contents up to 8%. Those metastable layers stay...

Shock wave of vapor-liquid two-phase flow

Institute of Scientific and Technical Information of China (English)

Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

2008-01-01

The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

Multi-component vapor-liquid equilibrium model for LES of high-pressure fuel injection and application to ECN Spray A

NARCIS (Netherlands)

Matheis, Jan; Hickel, S.

2018-01-01

We present and evaluate a two-phase model for Eulerian large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model is based on cubic equations of state and vapor-liquid equilibrium calculations and can represent the coexistence of supercritical states and

Vaporization of the prototypical ionic liquid BMImNTf₂ under equilibrium conditions: a multitechnique study.

Science.gov (United States)

Brunetti, Bruno; Ciccioli, Andrea; Gigli, Guido; Lapi, Andrea; Misceo, Nicolaemanuele; Tanzi, Luana; Vecchio Ciprioti, Stefano

2014-08-07

The vaporization behaviour and thermodynamics of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf2) were studied by combining the Knudsen Effusion Mass Loss (KEML) and Knudsen Effusion Mass Spectrometry (KEMS) techniques. KEML studies were carried out in a large temperature range (398-567) K by using effusion orifices with 0.3, 1, and 3 mm diameters. The vapor pressures so measured revealed no kinetically hindered vaporization effects and provided second-law vaporization enthalpies at the mean experimental temperatures in close agreement with literature. By exploiting the large temperature range covered, the heat capacity change associated with vaporization was estimated, resulting in a value of -66.8 J K(-1) mol(-1), much lower than that predicted from calorimetric measurements on the liquid phase and theoretical calculations on the gas phase. The conversion of the high temperature vaporization enthalpy to 298 K was discussed and the value Δ(l)(g)H(m)(298 K) = (128.6 ± 1.3) kJ mol(-1) assessed on the basis of data from literature and present work. Vapor pressure data were also processed by the third-law procedure using different estimations for the auxiliary thermal functions, and a Δ(l)(g)H(m)(298 K) consistent with the assessed value was obtained, although the overall agreement is sensitive to the accuracy of heat capacity data. KEMS measurements were carried out in the lower temperature range (393-467) K and showed that the largely prevailing ion species is BMIm(+), supporting the common view of BMImNTf2 vaporizing as individual, neutral ion pairs also under equilibrium conditions. By monitoring the mass spectrometric signal of this ion as a function of temperature, a second-law Δ(l)(g)H(m)(298 K) of 129.4 ± 7.3 kJ mol(-1) was obtained, well consistent with KEML and literature results. Finally, by combining KEML and KEMS measurements, the electron impact ionization cross section of BMIm(+) was estimated.

Similarities and differences in vapor explosion criteria

International Nuclear Information System (INIS)

Cronenberg, A.W.

1978-01-01

An overview of recent ideas pertaining to vapor explosion criteria indicates that in general sense, a consensus of opinion is emerging on the conditions applicable to explosive vaporization. Experimental and theoretical work has lead a number of investigators to the formulation of such conditions which are quite similar in many respects, although the quantitative details of the model formulation of such conditions are somewhat different. All model concepts are consistent in that an initial period of stable film boiling, separating molten fuel from coolant, is considered necessary (at least for large-scale interactions and efficient intermixing), with subsequent breakdown of film boiling due to pressure and/or thermal effects, followed by intimate fuel-coolant contact and a rapid vaporization process which is sufficient to cause shock pressurization. Although differences arise as to the conditions for and the energetics associated with film boiling destabilization and the mode and energetics of fragmentation and intermixing. However, the principal area of difference seems to be the question of what constitutes the requisite condition(s) for rapid vapor production to cause shock pressurization

High-Accuracy Measurements of Total Column Water Vapor From the Orbiting Carbon Observatory-2

Science.gov (United States)

Nelson, Robert R.; Crisp, David; Ott, Lesley E.; O'Dell, Christopher W.

2016-01-01

Accurate knowledge of the distribution of water vapor in Earth's atmosphere is of critical importance to both weather and climate studies. Here we report on measurements of total column water vapor (TCWV) from hyperspectral observations of near-infrared reflected sunlight over land and ocean surfaces from the Orbiting Carbon Observatory-2 (OCO-2). These measurements are an ancillary product of the retrieval algorithm used to measure atmospheric carbon dioxide concentrations, with information coming from three highly resolved spectral bands. Comparisons to high-accuracy validation data, including ground-based GPS and microwave radiometer data, demonstrate that OCO-2 TCWV measurements have maximum root-mean-square deviations of 0.9-1.3mm. Our results indicate that OCO-2 is the first space-based sensor to accurately and precisely measure the two most important greenhouse gases, water vapor and carbon dioxide, at high spatial resolution [1.3 x 2.3 km(exp. 2)] and that OCO-2 TCWV measurements may be useful in improving numerical weather predictions and reanalysis products.

Henry's Law vaporization studies and thermodynamics of einsteinium-253 metal dissolved in ytterbium

International Nuclear Information System (INIS)

Kleinschmidt, P.D.; Ward, J.W.; Matlack, G.M.; Haire, R.G.

1984-01-01

The cohesive energy of metallic einsteinium determines whether einsteinium is a trivalent or divalent metal. The enthalpy of sublimation, a measure of the cohesive energy, is calculated from the partial pressures of einsteinium over an alloy. The partial pressure of 253 Es has been measured over the range 470--870 K, using combined target and mass spectrometric Knudsen effusion techniques. An alloy was prepared with einsteinium dissolved in a ytterbium solvent to produce a very dilute solution. Partial pressure measurements on the alloy were amenable to the experimental technique and a data analysis using a Henry's law treatment of the data. Vapor pressure data are combined with an estimated crystal entropy S 0 298 and ΔC 0 /sub p/ for ytterbium, to produce enthalpy, entropy, and free energy functions from 298 to 1300 K. The vapor pressure of einsteinium in a dilute einsteinium--ytterbium alloy is described by the equation log P(atm) = -(6815 +- 216)/T+2.576 +- 0.337, from which we calculate for the enthalpy of sublimation of pure einsteinium ΔH 0 298 (second law) = 31.76 kcal/mol. The value of the enthalpy of sublimation is consistent with the conclusion that Es is a divalent metal

Vapor Pressure and Predicted Stability of American Contact Dermatitis Society Core Allergens

Science.gov (United States)

Jou, Paul C.; Siegel, Paul D.; Warshaw, Erin M.

2018-01-01

Background Accurate patch testing is reliant on proper preparation of patch test allergens. The stability of patch test allergens is dependent on several factors including vapor pressure (VP). Objective This investigation reviews the VP of American Contact Dermatitis Society Core Allergens and compares stability predictions based on VP with those established through clinical testing. Methods Standard references were accessed for determining VP in millimeters of mercury and associated temperature in degrees celsius. If multiple values were listed, VP at temperatures that most approximate indoor storage conditions (20°C and 25°C) were chosen. For mixes, the individual component with the highest VP was chosen as the overall VP, assuming that the most volatile substance would evaporate first. Antigens were grouped into low (≤0.001 mm Hg), moderate (0.001 mm Hg), and high (≥1 mm Hg) volatility using arbitrary cutoff values. Conclusions This review is consistent with previously reported data on formaldehyde, acrylates, and fragrance material instability. Given lack of testing data, VP can be useful in predicting patch test compound stability. Measures such as air-tight multidose reagent containers, sealed single-application dispensers, preparation of patches immediately before application, and storage at lower temperatures may remedy some of these issues. PMID:27427821

40 CFR 52.787 - Gasoline transfer vapor control.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.787... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Indiana § 52.787 Gasoline transfer vapor control. (a) Gasoline means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

Vaporization thermodynamics and enthalpy of formation of aluminum silicon carbide

International Nuclear Information System (INIS)

Behrens, R.G.; Rinehart, G.H.

1984-01-01

The vaporization thermodynamics of aluminum silicon carbide was investigated using Knudsen effusion mass spectrometry. Vaporization occurred incongruently to give Al(g), SiC(s), and graphite as reaction products. The vapor pressure of aluminum above (Al 4 SiC 4 + SiC + C) was measured using graphite effusion cells with orifice areas between 1.1 X 10 -2 and 3.9 X 10 -4 cm 2 . The vapor pressure of aluminum obtained between 1427 and 1784 K using an effusion cell with the smallest orifice area, 3.9 X 10 -4 cm 2 , is expressed as log p (Pa) = - (18567 + or - 86) (K/T) + (12.143 + or - 0.054) The third-law calculation of the enthalpy change for the reaction Al 4 SiC 4 (s) = 4Al(g) + SiC(hex) + 3C(s) using the present aluminum pressures gives ΔH 0 (298.15 K) = (1455 + or - 79) kJ /SUP ./ mol -1 . The corresponding second-law result is ΔH 0 (298.15 K) = (1456 + or - 47) kJ /SUP ./ mol -1 . The standard enthalpy of formation of Al 4 SiC 4 (s) from the elements calculated from the present vaporization enthalpy (third-law calculation) and the enthalpies of formation of Al(g) and hexagonal SiC is ΔH 0 /SUB f/ (298.15 K) = -(221 + or - 85) kJ /SUP ./ mol -1 . The standard enthalpy of formation of Al 4 SiC 4 (s) from its constituent carbides Al 4 C 3 (s) and SiC(c, hex) is calculated to be ΔH 0 (298.15 K) = (38 + or - 92) KJ /SUP ./ mol -1

Bubble point pressures of binary system of methanol and methyl propionate

NARCIS (Netherlands)

Shariati, A.; Florusse, L.J.; Kroon, M.C.; Peters, C.J.

2016-01-01

In this work, bubble point pressures of the system of methanol + methyl propionate were measured for several isopleths within temperature and pressure ranges of 382-444 K and 0.437-2.285 MPa, respectively. The vapor pressures of pure methanol and methyl propionate were also measured. The two-suffix

Kinetics of low pressure chemical vapor deposition of tungsten silicide from dichlorocilane reduction of tungsten hexafluoride

International Nuclear Information System (INIS)

Srinivas, D.; Raupp, G.B.; Hillman, J.

1990-01-01

The authors report on experiments to determine the intrinsic surface reaction rate dependences and film properties' dependence on local reactant partial pressures and wafer temperature in low pressure chemical vapor deposition (LPCVD) of tungsten silicide from dichlorosilane reduction of tungsten hexafluoride. Films were deposited in a commercial-scale Spectrum CVD cold wall single wafer reactor under near differential, gradientless conditions. Over the range of process conditions investigated, deposition rate was found to be first order in dichlorosillane and negative second order in tungsten hexafluoride partial pressure. The apparent activation energy in the surface reaction limited regime was found to be 70-120 kcal/mol. The silicon to tungsten ratio of as deposited silicide films ranged from 1.1 to 2.4, and increased with increasing temperature and dichlorosillane partial pressure, and decreased with increasing tungsten hexafluoride pressure. These results suggest that the apparent silicide deposition rate and composition are controlled by the relative rates of at least two competing reactions which deposit stoichiometric tungsten silicides and/or silicon

Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

Science.gov (United States)

Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao

2008-01-01

Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

Iron exclusion in rice genotypes as affected by different vapor pressure deficit conditions

Directory of Open Access Journals (Sweden)

Ram Kumar Shrestha

2015-08-01

Full Text Available Root iron (Fe exclusion capacity of four lowland rice genotypes were evaluated in increasing rate of Fe2+ stresses (0, 500, 1000 and 1500 mg/L in growing medium under the conditions of low and high vapor pressure deficit. Rice root excluded significantly higher amount of iron under dry atmospheric condition (655 mg Fe/g root dry matter than moist atmospheric condition (118 mg Fe/g root dry matter. But their iron exclusion capacity reduced when they were gradually exposed to the higher levels of Fe stress. Tolerant genotype such as TOX3107 excluded more iron when they were exposed to dry atmospheric condition.

Phosphorus atomic layer doping in SiGe using reduced pressure chemical vapor deposition

International Nuclear Information System (INIS)

Yamamoto, Yuji; Heinemann, Bernd; Murota, Junichi; Tillack, Bernd

2014-01-01

Phosphorus (P) atomic layer doping in SiGe is investigated at temperatures between 100 °C to 600 °C using a single wafer reduced pressure chemical vapor deposition system. SiGe(100) surface is exposed to PH 3 at different PH 3 partial pressures by interrupting SiGe growth. The impact of the SiGe buffer/cap growth condition (total pressure/SiGe deposition precursors) on P adsorption, incorporation, and segregation are investigated. In the case of SiH 4 -GeH 4 -H 2 gas system, steeper P spikes due to lower segregation are observed by SiGe cap deposition at atmospheric (ATM) pressure compared with reduced pressure (RP). The steepness of P spike of ∼ 5.7 nm/dec is obtained for ATM pressure without reducing deposition temperature. This result may be due to the shift of equilibrium of P adsorption/desorption to desorption direction by higher H 2 pressure. Using Si 2 H 6 -GeH 4 -H 2 gas system for SiGe cap deposition in RP, lowering the SiGe growth temperature is possible, resulting in higher P incorporation and steeper P profile due to reduced desorption and segregation. In the case of Si 2 H 6 -GeH 4 -H 2 gas system, the P dose could be simulated assuming a Langmuir-type kinetics model. Incorporated P shows high electrical activity, indicating P is adsorbed mostly in lattice position. - Highlights: • Phosphorus (P) atomic layer doping in SiGe (100) is investigated using CVD. • P adsorption is suppressed by the hydrogen termination of Ge surface. • By SiGe cap deposition at atmospheric pressure, P segregation was suppressed. • By using Si 2 H 6 -based SiGe cap, P segregation was also suppressed. • The P adsorption process is self-limited and follows Langmuir-type kinetics model

Differential absorption lidar measurements of atmospheric water vapor using a pseudonoise code modulated AlGaAs laser. Thesis

Science.gov (United States)

Rall, Jonathan A. R.

1994-01-01

Lidar measurements using pseudonoise code modulated AlGaAs lasers are reported. Horizontal path lidar measurements were made at night to terrestrial targets at ranges of 5 and 13 km with 35 mW of average power and integration times of one second. Cloud and aerosol lidar measurements were made to thin cirrus clouds at 13 km altitude with Rayleigh (molecular) backscatter evident up to 9 km. Average transmitter power was 35 mW and measurement integration time was 20 minutes. An AlGaAs laser was used to characterize spectral properties of water vapor absorption lines at 811.617, 816.024, and 815.769 nm in a multipass absorption cell using derivative spectroscopy techniques. Frequency locking of an AlGaAs laser to a water vapor absorption line was achieved with a laser center frequency stability measured to better than one-fifth of the water vapor Doppler linewidth over several minutes. Differential absorption lidar measurements of atmospheric water vapor were made in both integrated path and range-resolved modes using an externally modulated AlGaAs laser. Mean water vapor number density was estimated from both integrated path and range-resolved DIAL measurements and agreed with measured humidity values to within 6.5 percent and 20 percent, respectively. Error sources were identified and their effects on estimates of water vapor number density calculated.

40 CFR 52.255 - Gasoline transfer vapor control.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Gasoline transfer vapor control. 52.255... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS California § 52.255 Gasoline transfer vapor control. (a) “Gasoline” means any petroleum distillate having a Reid vapor pressure of 4 pounds or greater...

Identification of Alternative Vapor Intrusion Pathways Using Controlled Pressure Testing, Soil Gas Monitoring, and Screening Model Calculations.

Science.gov (United States)

Guo, Yuanming; Holton, Chase; Luo, Hong; Dahlen, Paul; Gorder, Kyle; Dettenmaier, Erik; Johnson, Paul C

2015-11-17

Vapor intrusion (VI) pathway assessment and data interpretation have been guided by an historical conceptual model in which vapors originating from contaminated soil or groundwater diffuse upward through soil and are swept into a building by soil gas flow induced by building underpressurization. Recent studies reveal that alternative VI pathways involving neighborhood sewers, land drains, and other major underground piping can also be significant VI contributors, even to buildings beyond the delineated footprint of soil and groundwater contamination. This work illustrates how controlled-pressure-method testing (CPM), soil gas sampling, and screening-level emissions calculations can be used to identify significant alternative VI pathways that might go undetected by conventional sampling under natural conditions at some sites. The combined utility of these tools is shown through data collected at a long-term study house, where a significant alternative VI pathway was discovered and altered so that it could be manipulated to be on or off. Data collected during periods of natural and CPM conditions show that the alternative pathway was significant, but its presence was not identifiable under natural conditions; it was identified under CPM conditions when measured emission rates were 2 orders of magnitude greater than screening-model estimates and subfoundation vertical soil gas profiles changed and were no longer consistent with the conventional VI conceptual model.

The role of fragmentation mechanism in large-scale vapor explosions

International Nuclear Information System (INIS)

Liu, Jie

2003-01-01

A non-equilibrium, multi-phase, multi-component code PROVER-I is developed for propagation phase of vapor explosion. Two fragmentation models are used. The hydrodynamic fragmentation model is the same as Fletcher's one. A new thermal fragmentation model is proposed with three kinds of time scale for modeling instant fragmentation, spontaneous nucleation fragmentation and normal boiling fragmentation. The role of fragmentation mechanisms is investigated by the simulations of the pressure wave propagation and energy conversion ratio of ex-vessel vapor explosion. The spontaneous nucleation fragmentation results in a much higher pressure peak and a larger energy conversion ratio than hydrodynamic fragmentation. The instant fragmentation gives a slightly larger energy conversion ratio than spontaneous nucleation fragmentation, and the normal boiling fragmentation results in a smaller energy conversion ratio. The detailed analysis of the structure of pressure wave makes it clear that thermal detonation exists only under the thermal fragmentation circumstance. The high energy conversion ratio is obtained in a small vapor volume fraction. However, in larger vapor volume fraction conditions, the vapor explosion is weak. In a large-scale vapor explosion, the hydrodynamic fragmentation is essential when the pressure wave becomes strong, so a small energy conversion ratio is expected. (author)

Observation of vapor pressure enhancement of rare-earth metal-halide salts in the temperature range relevant to metal-halide lamps

Energy Technology Data Exchange (ETDEWEB)

Curry, J. J.; Henins, A.; Hardis, J. E. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Estupinan, E. G. [Osram Sylvania Inc., Beverly, Massachusetts 01915 (United States); Lapatovich, W. P. [Independent Consultant, 51 Pye Brook Lane, Boxford, Massachusetts 01921 (United States); Shastri, S. D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2012-02-20

Total vapor-phase densities of Dy in equilibrium with a DyI{sub 3}/InI condensate and Tm in equilibrium with a TmI{sub 3}/TlI condensate have been measured for temperatures between 900 K and 1400 K. The measurements show strong enhancements in rare-earth vapor densities compared to vapors in equilibrium with the pure rare-earth metal-halides. The measurements were made with x-ray induced fluorescence on the sector 1-ID beam line at the Advanced Photon Source. The temperature range and salt mixtures are relevant to the operation of metal-halide high-intensity discharge lamps.

SEAMIST trademark in-situ instrumentation and vapor sampling system applications in the Sandia Mixed Waste Landfill Integrated Demonstration Program

International Nuclear Information System (INIS)

Lowry, W.E.; Dunn, S.D.; Cremer, S.C.; Williams, C.

1994-01-01

The SEAMIST trademark inverting membrane deployment system has been used successfully at the Mixed Waste Landfill Integrated Demonstration (MWLID) for multipoint vapor sampling/pressure measurement/permeability measurement/sensor integration demonstrations and borehole lining. Several instruments were deployed inside the SEAMIST trademark lined boreholes to detect metals, radionuclides, moisture, and geologic variations. The liner protected the instruments from contamination, maintained support of the uncased borehole wall, and sealed the total borehole from air circulation. The current activities have included the installation of three multipoint vapor sampling systems and sensor integration systems in 100-foot-deep vertical boreholes. A long term pressure monitoring program has recorded barometric pressure effects at depth with relatively high spatial resolution. The SEAMIST trademark system has been integrated with a variety of hydrologic and chemical sensors for in-situ measurements, demonstrating its versatility as an instrument deployment system which allows easy emplacement and removal. Standard SEAMIST trademark vapor sampling systems were also integrated with state-of-the-art VOC analysis technologies (automated GC, UV laser fluorometer). The results and status of these demonstration tests are presented

Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions

KAUST Repository

Sharma, Ashish

2016-09-08

We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble for an accurate description of the discharge kinetics. We find that the dynamic characteristics of the streamer discharge are different at low and high positive trigger voltages with the axial streamer evolution dominant for low voltages and a surface hugging mode favored for high voltages. We also find a substantial difference in initiation, transition and evolution stages of discharge for positive and negative trigger voltages with the volumetric distribution of species in the streamer channel much more uniform for negative trigger voltages on account of the presence of multiple streamers. We observe that the presence of water vapor does not affect the breakdown voltage even for oversaturated conditions but significantly influences the composition of dominant species in the trail of the streamer as well as the flux of the dominant species on the bubble surface. © 2016 IOP Publishing Ltd.

Integration of thermo-vapor compressor with multiple-effect evaporator

International Nuclear Information System (INIS)

Sharan, Prashant; Bandyopadhyay, Santanu

2016-01-01

Highlights: • Energy integration of thermo-vapor compressor with multiple-effect evaporator. • Proposed a new methodology for optimal placement of thermo-vapor compressor. • Extended Pinch Analysis for overall energy conservation. • Obtained simultaneous reduction in evaporator area requirement and energy consumption with optimal integration. - Abstract: Thermo-vapor compressor (TVC) is used for compressing the low-pressure vapor with the help of the high-pressure motive steam, to produce the medium pressure vapor. A substantial portion of energy may be conserved by integrating TVC with the multiple-effect evaporator (MEE). The common practice in desalination industry is to compress the vapor produced in the last effect of a MEE using TVC to reduce the overall motive steam requirement. Such integration does not necessarily guarantee energy optimality. The objective of the present work is to optimally integrate TVC with a MEE system to maximize the gain output ratio (GOR). GOR is defined as the ratio of the mass flow rate of vapor produced in MEE to the mass flow rate of the motive steam supplied to TVC. GOR is the measure of the energy efficiency of MEE system. Using the principles of Pinch Analysis and techniques of mathematical optimization, a new methodology for integration of TVC with MEE is proposed in this paper. This is the first analytical methodology to optimally integrate TVC with MEE, avoiding multiple simulations of the overall system. A Theorem is proposed to directly calculate the optimal location of TVC suction position. The proposed methodology gives the designer the freedom to design an MEE-TVC with minimum energy consumption and without carrying out the detailed simulation of the entire system. The methodology is demonstrated through the illustrative case studies for concentrating corn glucose, and freshwater production through thermal desalination. In the case of corn glucose, the optimal integration of TVC with 2-effect MEE resulted in

Atmospheric Airborne Pressure Measurements Using the Oxygen A Band for the ASCENDS Mission

Science.gov (United States)

Riris, Haris; Rodriguez, Mike; Stephen, Mark; Hasselbrack, William; Allan, Graham; Mao, Jiamping,; Kawa, Stephan R.; Weaver, Clark J.

2011-01-01

We report on airborne atmospheric pressure measurements using new fiber-based laser technology and the oxygen A-band at 765 nm. Remote measurements of atmospheric temperature and pressure are required for a number of NASA Earth science missions and specifically for the Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission. Accurate measurements of tropospheric CO2 on a global scale are very important in order to better understand its sources and sinks and to improve predictions on any future climate change. The ultimate goal of a CO2 remote sensing mission, such as ASCENDS, is to derive the CO2 concentration in the atmosphere in terms of mole fraction in unit of parts-per-million (ppmv) with regard to dry air. Therefore, both CO2 and the dry air number of molecules in the atmosphere are needed in deriving this quantity. O2 is a stable molecule and uniformly mixed in the atmosphere. Measuring the O2 absorption in the atmosphere can thus be used to infer the dry air number of molecules and then used to calculate CO2 concentration. With the knowledge of atmospheric water vapor, we can then estimate the total surface pressure needed for CO2 retrievals. Our work, funded by the ESTO IIP program, uses fiber optic technology and non-linear optics to generate 765 nm laser radiation coincident with the Oxygen A-band. Our pulsed, time gated technique uses several on- and off-line wavelengths tuned to the O2 absorption line. The choice of wavelengths allows us to measure the pressure by using two adjacent O2 absorptions in the Oxygen A-band. Our retrieval algorithm fits the O2 lineshapes and derives the pressure. Our measurements compare favorably with a local weather monitor mounted outside our laboratory and a local weather station.

Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

Directory of Open Access Journals (Sweden)

Dora M. Paolucci

2011-03-01

Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

Vaporization and thermodynamics of forsterite-rich olivine and some implications for silicate atmospheres of hot rocky exoplanets

Science.gov (United States)

Costa, Gustavo C. C.; Jacobson, Nathan S.; Fegley, Bruce, Jr.

2017-06-01

We describe an experimental and theoretical study of olivine [Mg2SiO4 (Fo)-Fe2SiO4 (Fa)] vaporization. The vaporization behavior and thermodynamic properties of a fosterite-rich olivine (Fo95Fa5) have been explored by high-temperature Knudsen effusion mass spectrometry (KEMS) from 1750 to 2250 K. The gases observed (in order of decreasing partial pressure) are Fe, SiO, Mg, O2 and O. We measured the solidus temperature (∼2050 K), partial pressures of individual gases, the total vapor pressure, and thermodynamic activities and partial molar enthalpies of MgO, 'FeO', and SiO2 for the Fo95Fa5 olivine. The results are compared to other measurements and models of the olivine system. Our experimental data show olivine vaporizes incongruently. We discuss this system both as a psuedo-binary of Fo-Fa and a psuedo-ternary of MgO-'FeO'-SiO2. Iron/magnesium molar ratios in the sample before (∼0.05) and after (∼0.04) vaporization are consistent with the small positive deviations from ideality of fayalite (γ ∼ 1.17) in olivine of the composition studied (e.g., Nafziger and Muan, 1967). Our data for olivine + melt confirm prior theoretical models predicting fractional vaporization of Fe relative to Mg from molten silicates (Fegley and Cameron, 1987; Schaefer and Fegley, 2009; Ito et al., 2015). If loss of silicate atmospheres occurs from hot rocky exoplanets with magma oceans the residual planet may be enriched in magnesium relative to iron.

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

Science.gov (United States)

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

1996-01-01

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

Microscale interfacial behavior at vapor film collapse on high-temperature particle surface

International Nuclear Information System (INIS)

Abe, Yutaka; Tochio, Daisuke

2009-01-01

It has been pointed out that vapor film on a premixed high-temperature droplet surface should be collapsed to trigger vapor explosion. Thus, it is important to clarify the micromechanism of vapor film collapse behavior for the occurrence of vapor explosion. In the present study, microscale vapor-liquid interface behavior upon vapor film collapse caused by an external pressure pulse is experimentally observed and qualitatively analyzed. In the analytical investigation, interfacial temperature and interface movement were estimated with heat conduction analysis and visual data processing technique. Results show that condensation can possibly occur at the vapor-liquid interface when the pressure pulse arrived. That is, this result indicates that the vapor film collapse behavior is dominated not by fluid motion but by phase change. (author)

Calculational model for condensation of water vapor during an underground nuclear detonation

International Nuclear Information System (INIS)

Knox, R.J.

1975-01-01

An empirally derived mathematical model was developed to calculate the pressure and temperature history during condensation of water vapor in an underground-nuclear-explosion cavity. The condensation process is non-isothermal. Use has been made of the Clapeyron-Clausius equation as a basis for development of the model. Analytic fits to the vapor pressure and the latent heat of vaporization for saturated-water vapor, together with an estimated value for the heat-transfer coefficient, have been used to describe the phenomena. The calculated pressure-history during condensation has been determined to be exponential, with a time constant somewhat less than that observed during the cooling of the superheated steam from the explosion. The behavior of the calculated condensation-pressure compares well with the observed-pressure record (until just prior to cavity collapse) for a particular nuclear-detonation event for which data is available

Effects of molten material temperatures and coolant temperatures on vapor explosion

Institute of Scientific and Technical Information of China (English)

LI Tianshu; YANG Yanhua; YUAN Minghao; HU Zhihua

2007-01-01

An observable experiment facility for low-temperature molten materials to be dropped into water was set up in this study to investigate the mechanism of the vapor explosion. The effect of the fuel and coolant interaction(FCI) on the vapor explosion during the severe accidents of a fission nuclear reactor has been studied. The experiment results showed that the molten material temperature has an important effect on the vapor explosion behavior and pressure. The increase of the coolant temperature would decrease the pressure of the vapor explosion.

Stability limit of liquid water in metastable equilibrium with subsaturated vapors.

Science.gov (United States)

Wheeler, Tobias D; Stroock, Abraham D

2009-07-07

A pure liquid can reach metastable equilibrium with its subsaturated vapor across an appropriate membrane. This situation is analogous to osmotic equilibrium: the reduced chemical potential of the dilute phase (the subsaturated vapor) is compensated by a difference in pressure between the phases. To equilibrate with subsaturated vapor, the liquid phase assumes a pressure that is lower than its standard vapor pressure, such that the liquid phase is metastable with respect to the vapor phase. For sufficiently subsaturated vapors, the liquid phase can even assume negative pressures. The appropriate membrane for this metastable equilibrium must provide the necessary mechanical support to sustain the difference in pressure between the two phases, limit nonhomogeneous mechanisms of cavitation, and resist the entry of the dilutant (gases) into the pure phase (liquid). In this article, we present a study of the limit of stability of liquid water--the degree of subsaturation at which the liquid cavitates--in this metastable state within microscale voids embedded in hydrogel membranes. We refer to these structures as vapor-coupled voids (VCVs). In these VCVs, we observed that liquid water cavitated when placed in equilibrium with vapors of activity aw,vapairhumiditynucleation theory or molecular simulations (Pcav=-140 to -180 MPa). To determine the cause of the disparity between the observed and predicted stability limit, we examine experimentally the likelihood of several nonhomogeneous mechanisms of nucleation: (i) heterogeneous nucleation caused by hydrophobic patches on void walls, (ii) nucleation caused by the presence of dissolved solute, (iii) nucleation caused by the presence of pre-existing vapor nuclei, and (iv) invasion of air through the hydrogel membrane into the voids. We conclude that, of these possibilities, (i) and (ii) cannot be discounted, whereas (iii) and (iv) are unlikely to play a role in determining the stability limit.

Laboratory Measurements of the 940, 1130, and 1370 nm Water Vapor Absorption Band Profiles

Science.gov (United States)

Giver, Lawrence P.; Gore, Warren J.; Pilewskie, P.; Freedman, R. S.; Chackerian, C., Jr.; Varanasi, P.

2001-01-01

We have used the solar spectral flux radiometer (SSFR) flight instrument with the Ames 25 meter base-path White cell to obtain about 20 moderate resolution (8 nm) pure water vapor spectra from 650 to 1650 nm, with absorbing paths from 806 to 1506 meters and pressures up to 14 torr. We also obtained a set at 806 meters with several different air-broadening pressures. Model simulations were made for the 940, 1130, and 1370 nm absorption bands for some of these laboratory conditions using the Rothman, et al HITRAN-2000 linelist. This new compilation of HITRAN includes new intensity measurements for the 940 nm region. We compared simulations for our spectra of this band using HITRAN-2000 with simulations using the prior HITRAN-1996. The simulations of the 1130 nm band show about 10% less absorption than we measured. There is some evidence that the total intensity of this band is about 38% stronger than the sum of the HITRAN line intensities in this region. In our laboratory conditions the absorption depends approximately on the square root of the intensity. Thus, our measurements agree that the band is stronger than tabulated in HITRAN, but by about 20%, substantially less than the published value. Significant differences have been shown between Doppler-limited resolution spectra of the 1370 nm band obtained at the Pacific Northwest National Laboratory and HITRAN simulations. Additional new intensity measurements in this region are continuing to be made. We expect the simulations of our SSFR lab data of this band will show the relative importance of improving the HITRAN line intensities of this band for atmospheric measurements.

Accurate and stable equal-pressure measurements of water vapor transmission rate reaching the 10-6 g m-2 day-1 range

Science.gov (United States)

Nakano, Yoichiro; Yanase, Takashi; Nagahama, Taro; Yoshida, Hajime; Shimada, Toshihiro

2016-10-01

The water vapor transmission rate (WVTR) of a gas barrier coating is a critically important parameter for flexible organic device packaging, but its accurate measurement without mechanical stress to ultrathin films has been a significant challenge in instrumental analysis. At the current stage, no reliable results have been reported in the range of 10-6 g m-2 day-1 that is required for organic light emitting diodes (OLEDs). In this article, we describe a solution for this difficult, but important measurement, involving enhanced sensitivity by a cold trap, stabilized temperature system, pumped sealing and calibration by a standard conductance element.

Vapor-transport of tungsten and its geologic application

Energy Technology Data Exchange (ETDEWEB)

Shibue, Y [Hyogo Univ. of Teacher Education, Hyogo (Japan)

1988-11-10

The volatility of tungsten in a hydrous system at elevated temperatures and pressures was examined, and a tentative model for the enrichment of tungsten in hydrothermal solutions for the deposits related to granitic activities was proposed. To produce vapor-saturated solution, 17 or 15ml of 20wt% NaCl solution was introduced into an autoclave. Ca(OH){sub 2} for tungsten and H{sub 2}WO{sub 4} for base metals were used as vapor-captures, and run products were identified by X-ray powder diffractometry. The results suggested that the ratio of tungsten to base metals was higher in a vapor phase than in a liquid phase, and more enrichment of tungsten in the vapor phase occurred at higher temperature and pressure under the coexistence of the vapor and liquid phase. The tentative model emphasizing the vapor-transport of tungsten could explain the presence of tungsten deposits without large mineralization of base metals. Geological schematic model for the generation of the hydrothermal solution enriched in tungsten compared with base metals was illustrated based on above mentioned results. 21 refs., 3 figs.

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

Directory of Open Access Journals (Sweden)

J. F. Pankow

2008-05-01

Full Text Available The SIMPOL.1 group contribution method is developed for predicting the liquid vapor pressure p^o_L (atm and enthalpy of vaporization Δ H_vap (kJ mol^-1 of organic compounds as functions of temperature (T. For each compound i, the method assumes log₁₀p^o_L,i (T=∑_kν_k,ib_k(T where ν_k,i is the number of groups of type k, and b_k (T is the contribution to log₁₀p^o_L,i (T by each group of type k. A zeroeth group is included that uses b₀ (T with ν_0,i=1 for all i. A total of 30 structural groups are considered: molecular carbon, alkyl hydroxyl, aromatic hydroxyl, alkyl ether, alkyl ring ether, aromatic ether, aldehyde, ketone, carboxylic acid, ester, nitrate, nitro, alkyl amine (primary, secondary, and tertiary, aromatic amine, amide (primary, secondary, and tertiary, peroxide, hydroperoxide, peroxy acid, C=C, carbonylperoxynitrate, nitro-phenol, nitro-ester, aromatic rings, non-aromatic rings, C=C–C=O in a non-aromatic ring, and carbon on the acid-side of an amide. The T dependence in each of the b_k (T is assumed to follow b(T=B₁/T+B₂+B₃T+B₄ln T. Values of the B coefficients are fit using an initial basis set of 272 compounds for which experimentally based functions p^o _L,i=f_i (T are available. The range of vapor pressure considered spans fourteen orders of magnitude. The ability of the initially fitted B coefficients to predict p^o_L values is examined using a test set of 184 compounds and a T range that is as wide as 273

Phase Equilibrium Measurements and Modeling of 1-Propanethiol+1-Butanethiol + CH4 in Methane Ternary System at 303, 336, and 368 K and Pressure Up to 9 MPa

DEFF Research Database (Denmark)

Awan, Javeed A.; Coquelet, Christophe; Tsivintzelis, Ioannis

2016-01-01

New vapor-liquid equilibrium (VLE) data for 1-propanethiol + 1-butanethiol + CH4 ternary system is reported. Measurements were performed at three different temperatures (303, 336, and 368 K), and the pressure ranged from 1 to 9 MPa. The total system pressure was maintained by CH4. The inlet mole...

A demonstration experiment for studying the properties of saturated vapor

Science.gov (United States)

Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

2017-11-01

The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

High-temperature vaporization behavior of oxygen-deficient thoria

International Nuclear Information System (INIS)

Ackermann, R.J.; Tetenbaum, M.

1979-01-01

The experimental results of the present study on the vaporization behavior of oxygen-deficient thoria are directed toward a more precise and detailed study of the lower phase boundary (l.p.b.) and congruently vaporizing composition (c.v.c), and intermediate compositions, and the corresponding oxygen potentials and total pressure at temperatures above 2000K. The l.p.b. and c.v.c. values were found to fit an equation of the form log x = A + (B/T), where x is the stoichiometric defect in ThO 2 -x. Oxygen potentials corresponding to the l.p.b. and c.v.c. have been estimated from vapor pressures and thermodynamic data. A very sharp decrease in oxygen potential occurs when thoria isreduced only slightly from the stoichiometric composition. In the temperature range from 2400 to 2655 K, the oxygen partial pressure dependency of x in ThO 2 -x was found to be approximately proportional to PO 2 - 1 /4to PO 2 - 1 /. The small extent of reduction over a wide range of oxygen potentials at these temperatures is a clear illustration of the higher stability of the ThO 2 -x phase compared with that of UO 2 -x. Values of ΔHO 2 and ΔSO 2 have been estimated for selected compositions from the dependence of the measured oxygen potential on temperature. Estimates of the standard free energy of formation of bivariant ThO 2 -x compositions have been made. A substantial increase in the total pressure of thorium-bearing species occurs when stoichiometric thoria is reduced toward the lower phase boundary. (orig.) [de

Research on the fundamental process of thermal-hydraulic behaviors in severe accident. Vapor film collapse behavior on high temperature particle surface. JAERI's nuclear research promotion program, H10-027-3. Contract research

International Nuclear Information System (INIS)

Abe, Yutaka

2002-03-01

The experimental researches were conducted to study vapor film collapse behavior on high temperature melted core material coarsely mixed in the coolant under the film boiling condition. The film collapse is very important incipient incident of the trigger process for the vapor explosion in sever accident of nuclear reactor. In the experiment, pressure pulse was applied to the vapor film on a high temperature particle surface simulating melted core material to observed microscopic vapor film collapse behavior with a high-speed video camera of 40,500 fps. The particle surface temperature and pressure around the particle were simultaneously measured. The transition of the vapor film thickness and two-dimensional vapor-liquid interface movement and the velocity were estimated with visual data analysis technique, PIV and digital data analysis technique. Furthermore, heat conduction analysis was performed to estimate the vapor-liquid interfacial temperature with the measured temperature and estimated vapor film thickness. As the results, it was clarified that the vapor-liquid interface changed white from transparent view for all the experimental conditions. It is also clarified that the vapor-liquid interfacial temperature decreased under the saturation temperature when the pressure pulse arrive at the particle. The experimental facts indicates the possibility that the vapor film collapse occurs due to the liquid phase homogeneous moving toward the particle drove by the pressure reduction caused by the phase change inside the vapor film. (author)

Vaporization study on lanthanum-neodymium alloys by mass-spectrometry

International Nuclear Information System (INIS)

Shoji, Y.; Matsui, T.

1999-01-01

Partial vapor pressure of Nd(g) over La x Nd 1-x alloys (x = 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80 and 0.90) was measured with a time-of-flight mass-spectrometer equipped with a tungsten Knudsen cell over the temperature range of 1474-1767 K. Thermodynamic activity of neodymium in the liquid alloys was determined by comparing the partial vapor pressure of Nd(g) over the alloys with that over the pure metal. The thermodynamic activity of lanthanum in the alloys was calculated from that of neodymium obtained experimentally in this study by graphic integration using the Gibbs-Duhem equation. Both activities for each element, thus obtained, showed positive deviations from Raoult's law over the entire compositional range. Thermodynamic quantities such as Gibbs free energy of formation, excess enthalpy etc. were also calculated from the thermodynamic activities. (orig.)

Surface measurements of upper tropospheric water vapor isotopic composition on the Chajnantor Plateau, Chile

Science.gov (United States)

Galewsky, Joseph; Rella, Christopher; Sharp, Zachary; Samuels, Kimberly; Ward, Dylan

2011-09-01

Simultaneous, real-time measurements of atmospheric water vapor mixing ratio and isotopic composition (δD and δ18O) were obtained using cavity ringdown spectroscopy on the arid Chajnantor Plateau in the subtropical Chilean Andes (elevation 5080 m or 550 hPa; latitude 23°S) during July and August 2010. The measurements show surface water vapor mixing ratio as low as 215 ppmv, δD values as low as -540‰, and δ18O values as low as -68‰, which are the lowest atmospheric water vapor δ values reported from Earth's surface. The results are consistent with previous measurements from the base of the tropical tropopause layer (TTL) and suggest large-scale subsidence of air masses from the upper troposphere to the Earth's surface. The range of measurements is consistent with condensation under conditions of ice supersaturation and mixing with moister air from the lower troposphere that has been processed through shallow convection. Diagnostics using reanalysis data show that the extreme aridity of the Chajnantor Plateau is controlled by condensation in the upper tropical troposphere.

AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER

Directory of Open Access Journals (Sweden)

Muhammad Asmail Eleiwi

2013-05-01

Full Text Available Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle.  Two cases of  vapor compression refrigeration cycle were takenin this paper:  the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin  the second case the vapor compressionrefrigeration cycle with heat exchanger ; in these two cases, the temperatureat each point of  a vapor compressionrefrigeration cycle, the low and the high pressure ,the indoor temperature andthe outdoor temperature were measured at each time at compressor speed 1450 rpmand 2900 rpm for each blower speed 1, blower speed 2 and blower speed 3.Therefrigerant fluid was used in the vapor compression refrigeration cycle withoutIHE and with IHE is R134a..

42 CFR 84.163 - Man test for gases and vapors; Type C supplied-air respirators, demand and pressure-demand...

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Man test for gases and vapors; Type C supplied-air respirators, demand and pressure-demand classes; test requirements. 84.163 Section 84.163 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF...

Investigating the effects of water vaporization on the production of ...

African Journals Online (AJOL)

The simulations show that water vaporization increases productivity of well by increasing gas saturation and relative permeability near the well walls and improving the mobility of gas; and this effect is stronger in rich gas condensate reservoir than the lean ones. Keywords: Well, Gas, Pressure Drop, Vapor pressure of water ...

Differential Absorption Measurements of Atmospheric Water Vapor with a Coherent Lidar at 2050.532 nm

Science.gov (United States)

Koch, Grady J.; Dharamsi, Amin; Davis, Richard E.; Petros, Mulugeta; McCarthy, John C.

1999-01-01

Wind and water vapor are two major factors driving the Earth's atmospheric circulation, and direct measurement of these factors is needed for better understanding of basic atmospheric science, weather forecasting, and climate studies. Coherent lidar has proved to be a valuable tool for Doppler profiling of wind fields, and differential absorption lidar (DIAL) has shown its effectiveness in profiling water vapor. These two lidar techniques are generally considered distinctly different, but this paper explores an experimental combination of the Doppler and DIAL techniques for measuring both wind and water vapor with an eye-safe wavelength based on a solid-state laser material. Researchers have analyzed and demonstrated coherent DIAL water vapor measurements at 10 micrometers wavelength based on CO2 lasers. The hope of the research presented here is that the 2 gm wavelength in a holmium or thulium-based laser may offer smaller packaging and more rugged operation that the CO2-based approach. Researchers have extensively modeled 2 um coherent lasers for water vapor profiling, but no published demonstration is known. Studies have also been made, and results published on the Doppler portion, of a Nd:YAG-based coherent DIAL operating at 1.12 micrometers. Eye-safety of the 1.12 micrometer wavelength may be a concern, whereas the longer 2 micrometer and 10 micrometer systems allow a high level of eyesafety.

Durable Suit Bladder with Improved Water Permeability for Pressure and Environment Suits

Science.gov (United States)

Bue, Grant C.; Kuznetz, Larry; Orndoff, Evelyne; Tang, Henry; Aitchison, Lindsay; Ross, Amy

2009-01-01

Water vapor permeability is shown to be useful in rejecting heat and managing moisture accumulation in launch-and-entry pressure suits. Currently this is accomplished through a porous Gortex layer in the Advanced Crew and Escape Suit (ACES) and in the baseline design of the Constellation Suit System Element (CSSE) Suit 1. Non-porous dense monolithic membranes (DMM) that are available offer potential improvements for water vapor permeability with reduced gas leak. Accordingly, three different pressure bladder materials were investigated for water vapor permeability and oxygen leak: ElasthaneTM 80A (thermoplastic polyether urethane) provided from stock polymer material and two custom thermoplastic polyether urethanes. Water vapor, carbon dioxide and oxygen permeability of the DMM's was measured in a 0.13 mm thick stand-alone layer, a 0.08 mm and 0.05 mm thick layer each bonded to two different nylon and polyester woven reinforcing materials. Additional water vapor permeability and mechanical compression measurements were made with the reinforced 0.05 mm thick layers, further bonded with a polyester wicking and overlaid with moistened polyester fleece thermal underwear .This simulated the pressure from a supine crew person. The 0.05 mm thick nylon reinforced sample with polyester wicking layer was further mechanically tested for wear and abrasion. Concepts for incorporating these materials in launch/entry and Extravehicular Activity pressure suits are presented.

Water vapor self-continuum absorption measurements in the 4.0 and 2.1 μm transparency windows

Science.gov (United States)

Richard, L.; Vasilchenko, S.; Mondelain, D.; Ventrillard, I.; Romanini, D.; Campargue, A.

2017-11-01

In a recent contribution [A. Campargue, S. Kassi, D. Mondelain, S. Vasilchenko, D. Romanini, Accurate laboratory determination of the near infrared water vapor self-continuum: A test of the MT_CKD model. J. Geophys. Res. Atmos., 121,13,180-13,203, doi:10.1002/2016JD025531], we reported accurate water vapor absorption continuum measurements by Cavity Ring-down Spectroscopy (CRDS) and Optical-Feedback-Cavity Enhanced Absorption Spectroscopy (OF-CEAS) at selected spectral points of 4 near infrared transparency windows. In the present work, the self-continuum cross-sections, CS, are determined for two new spectral points. The 2491 cm-1 spectral point in the region of maximum transparency of the 4.0 μm window was measured by OF-CEAS in the 23-52 °C temperature range. The 4435 cm-1 spectral point of the 2.1 μm window was measured by CRDS at room temperature. The self-continuum cross-sections were determined from the pressure squared dependence of the continuum absorption. Comparison to the literature shows a reasonable agreement with 1970 s and 1980 s measurements using a grating spectrograph in the 4.0 μm window and a very good consistency with our previous laser measurements in the 2.1 μm window. For both studied spectral points, our values are much smaller than previous room temperature measurements by Fourier Transform Spectroscopy. Significant deviations (up to about a factor 4) are noted compared to the widely used semi empirical MT_CKD model of the absorption continuum. The measured temperature dependence at 2491 cm-1 is consistent with previous high temperature measurements in the 4.0 μm window and follows an exp(D0/kT) law, D0 being the dissociation energy of the water dimer.

Liquid-liquid contact in vapor explosion

International Nuclear Information System (INIS)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials

Interfacial Dynamics of Condensing Vapor Bubbles in an Ultrasonic Acoustic Field

Science.gov (United States)

Boziuk, Thomas; Smith, Marc; Glezer, Ari

2016-11-01

Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor bubbles are formed by direct injection from a pressurized steam reservoir through nozzles of varying characteristic diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor bubble and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in characteristic scale (and condensation rate) of the vapor bubbles.

Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

International Nuclear Information System (INIS)

Dan, Ho Jin; Lee, Joon Sik

2016-01-01

Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation

Modeling and measurement of boiling point elevation during water vaporization from aqueous urea for SCR applications

Energy Technology Data Exchange (ETDEWEB)

Dan, Ho Jin; Lee, Joon Sik [Seoul National University, Seoul (Korea, Republic of)

2016-03-15

Understanding of water vaporization is the first step to anticipate the conversion process of urea into ammonia in the exhaust stream. As aqueous urea is a mixture and the urea in the mixture acts as a non-volatile solute, its colligative properties should be considered during water vaporization. The elevation of boiling point for urea water solution is measured with respect to urea mole fraction. With the boiling-point elevation relation, a model for water vaporization is proposed underlining the correction of the heat of vaporization of water in the urea water mixture due to the enthalpy of urea dissolution in water. The model is verified by the experiments of water vaporization as well. Finally, the water vaporization model is applied to the water vaporization of aqueous urea droplets. It is shown that urea decomposition can begin before water evaporation finishes due to the boiling-point elevation.

Second-harmonic generation in atomic vapor with picosecond laser pulses

International Nuclear Information System (INIS)

Kim, D.; Mullin, C.S.; Shen, Y.R.

1997-01-01

Picosecond laser pulses were used to study the highly forbidden resonant second-harmonic generation (SHG) in potassium vapor. The input intensity dependence, vapor density dependence, buffer-gas pressure dependence, and spatial profile of the SHG were measured. A pump - probe experiment was conducted to probe the time dependence of the SHG signal. The experimental results can be understood from an ionization-initiated dc-field-induced SHG model. A theory of a dc-field-induced SHG model is developed that takes into account the time development of the dc electric field in detail. This temporal buildup of the dc field along with transient coherent excitation between two-photon-allowed transitions can explain the experimental results quantitatively, including the previous vapor SHG results with nanosecond laser pulses. copyright 1997 Optical Society of America

(Vapor + liquid + liquid) equilibrium measurements and correlation for {1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a)} system

International Nuclear Information System (INIS)

Zhao, Yanxing; Gong, Maoqiong; Dong, Xueqiang; Guo, Hao; Wu, Jianfeng

2014-01-01

Highlights: • VLLE data for the (R134 + R600a) system at temperatures ranging from (235.311 to 241.720) K was measured. • The experiment was carried out using an apparatus based on the recirculation of vapor into liquid. • Correlation of VLE data was made using PR−HV−NRTL model. • A strong critical opalescence was observed. - Abstract: In this work, a study on the (vapor + liquid + liquid) equilibrium (VLLE) for the (R134 + R600a) system was carried out using an apparatus based on the recirculation of vapor into liquid at temperatures ranging from (235.311 to 241.720) K. The uncertainties of the composition, temperature, and pressure were less than ±0.005, ±5 mK and ±0.5 kPa, respectively. Thirty-eight experimental p–T–x data covering both branches of the binodal boundary and nineteen experimental p–T–y data were presented. Three numerical methods were used to obtain the second liquid phase compositions coexisting in equilibrium, and all the three methods lead to consistent results. Moreover, all of the experimental data were correlated by the Peng–Robinson equation of state (PR EoS) with the Huron–Vidal (HV) mixing rule involving the non-random two-liquid (NRTL) activity coefficient model. Then the vapor phase compositions were calculated. The results show good agreement with the experimental data, and the maximum deviation is less than 0.006

Atmospheric water vapor: Distribution and Empirical estimation in the atmosphere of Thailand

Science.gov (United States)

Phokate, S.

2017-09-01

Atmospheric water vapor is a crucial component of the Earth’s atmosphere, which is shown by precipitable water vapor. It is calculated from the upper air data. In Thailand, the data were collected from four measuring stations located in Chiang Mai, Ubon Ratchathani, Bangkok, and Songkhla during the years 1998-2013. The precipitable water vapor obtained from this investigation were used to define an empirical model associated with the vapor pressure, which is a surface data at the same stations. The result shows that the relationship has a relatively high level of reliability. The precipitable water vapor obtained from the upper air data is nearly equal to the value from the model. The model was used to calculate the precipitable water vapor from the surface data 85 stations across the country. The result shows that seasonal change of the precipitable water vapor was low in the dry season (November-April) and high in the rainy season (May-October). In addition, precipitable water vapor varies along the latitudes of the stations. The high value obtains for low latitudes, but it is low for high latitudes.

Measurements of upper atmosphere water vapor made in situ with a new moisture sensor

Science.gov (United States)

Chleck, D.

1979-01-01

A new thin-film aluminum oxide sensor, Aquamax II, has been developed for the measurement of stratospheric and upper tropospheric water vapor levels. The sensor is briefly described with attention given to its calibration and performance. Data obtained from six balloon flights are presented; almost all the results show a constant water vapor mixing ratio, in agreement with other data from midlatitude regions.

Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window

International Nuclear Information System (INIS)

Ventrillard, I.; Romanini, D.; Mondelain, D.; Campargue, A.

2015-01-01

In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm −1 , respectively. Self-continuum cross sections, C S , were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the C S value at 4302 cm −1 is found 40% higher than predicted by the MT-CKD V2.5 model, while at 4723 cm −1 , our value is 5 times larger than the MT-CKD value. On the other hand, these OF-CEAS C S values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D 0 ≈ 1100 cm −1

The measurement of water vapor permeability of glove materials using dilute tritiated water

International Nuclear Information System (INIS)

Doughty, D.H.

1982-01-01

As fusion technology progresses, there will be an increasing need to handle tritium and tritiated compounds. Protective clothing, especially drybox gloves, must be an effective barrier to minimize worker exposure. The water vapor permeability of glove materials and finished glove constructions is a crucial property of drybox gloves and is not sufficiently well characterized. We have built an apparatus that measures water vapor permeability of elastomers using dilute tritiated water. The technique is more sensitive than other methods currently available and allows us to make measurements on materials and under conditions previously inaccessible. In particular, we present results on laminated drybox gloves for which data is not currently available. (orig.)

Research on the fundamental process of thermal-hydraulic behaviors in severe accident. Vapor film collapse behavior on high temperature particle surface. JAERI's nuclear research promotion program, H10-027-3. Contract research

Energy Technology Data Exchange (ETDEWEB)

Abe, Yutaka [Tsukuba Univ., Institute of Engineering Mechanics and Systems, Tsukuba, Ibaraki (Japan)

2002-03-01

The experimental researches were conducted to study vapor film collapse behavior on high temperature melted core material coarsely mixed in the coolant under the film boiling condition. The film collapse is very important incipient incident of the trigger process for the vapor explosion in sever accident of nuclear reactor. In the experiment, pressure pulse was applied to the vapor film on a high temperature particle surface simulating melted core material to observed microscopic vapor film collapse behavior with a high-speed video camera of 40,500 fps. The particle surface temperature and pressure around the particle were simultaneously measured. The transition of the vapor film thickness and two-dimensional vapor-liquid interface movement and the velocity were estimated with visual data analysis technique, PIV and digital data analysis technique. Furthermore, heat conduction analysis was performed to estimate the vapor-liquid interfacial temperature with the measured temperature and estimated vapor film thickness. As the results, it was clarified that the vapor-liquid interface changed white from transparent view for all the experimental conditions. It is also clarified that the vapor-liquid interfacial temperature decreased under the saturation temperature when the pressure pulse arrive at the particle. The experimental facts indicates the possibility that the vapor film collapse occurs due to the liquid phase homogeneous moving toward the particle drove by the pressure reduction caused by the phase change inside the vapor film. (author)

Optoacoustic measurements of water vapor absorption at selected CO laser wavelengths in the 5-micron region

Science.gov (United States)

Menzies, R. T.; Shumate, M. S.

1976-01-01

Measurements of water vapor absorption were taken with a resonant optoacoustical detector (cylindrical pyrex detector, two BaF2 windows fitted into end plates at slight tilt to suppress Fabry-Perot resonances), for lack of confidence in existing spectral tabular data for the 5-7 micron region, as line shapes in the wing regions of water vapor lines are difficult to characterize. The measurements are required for air pollution studies using a CO laser, to find the differential absorption at the wavelengths in question due to atmospheric constituents other than water vapor. The design and performance of the optoacoustical detector are presented. Effects of absorption by ambient NO are considered, and the fixed-frequency discretely tunable CO laser is found suitable for monitoring urban NO concentrations in a fairly dry climate, using the water vapor absorption data obtained in the study.

The influence of water vapor on atmospheric exchange measurements with an ICOS* based Laser absorption analyzer

Science.gov (United States)

Bunk, Rüdiger; Quan, Zhi; Wandel, Matthias; Yi, Zhigang; Bozem, Heiko; Kesselmeier, Jürgen

2014-05-01

Carbonyl sulfide and carbon monoxide are both atmospheric trace gases of high interest. Recent advances in the field of spectroscopy have enabled instruments that measure the concentration of the above and other trace gases very fast and with good precision. Increasing the effective path length by reflecting the light between two mirrors in a cavity, these instruments reach impressive sensitivities. Often it is possible to measure the concentration of more than one trace gas at the same time. The OCS/CO2 Analyzer by LGR (Los Gatos Research, Inc.) measures the concentration of water vapor [H2O], carbonyl sulfide [COS], carbon dioxide [CO2] and carbon monoxide [CO] simultaneously. For that the cavity is saturated with light, than the attenuation of light is measured as in standard absorption spectroscopy. The instrument proved to be very fast with good precision and to be able to detect even very low concentrations, especially for COS (as low as 30ppt in the case of COS). However, we observed a rather strong cross sensitivity to water vapor. Altering the water vapor content of the sampled air with two different methods led to a change in the perceived concentration of COS, CO and CO2. This proved especially problematic for enclosure (cuvette) measurements, where the concentrations of one of the above species in an empty cuvette are compared to the concentration of another cuvette containing a plant whose exchange of trace gases with the atmosphere is of interest. There, the plants transpiration leads to a large difference in water vapor content between the cuvettes and that in turn produces artifacts in the concentration differences between the cuvettes for the other above mentioned trace gases. For CO, simultaneous measurement with a UV-Emission Analyzer (AL 5002, Aerolaser) and the COS/CO Analyzer showed good agreement of perceived concentrations as long as the sample gas was dry and an increasing difference in perceived concentration when the sample gas was

Cost-benefit analysis of alternative LNG vapor-mitigation measures. Topical report, September 14, 1987-January 15, 1991

International Nuclear Information System (INIS)

Atallah, S.

1992-01-01

A generalized methodology is presented for comparing the costs and safety benefits of alternative hazard mitigation measures for a large LNG vapor release. The procedure involves the quantification of the risk to the public before and after the application of LNG vapor mitigation measures. In the study, risk was defined as the product of the annual accident frequency, estimated from a fault tree analysis, and the severity of the accident. Severity was measured in terms of the number of people who may be exposed to 2.5% or higher concentration. The ratios of the annual costs of the various mitigation measures to their safety benefits (as determined by the differences between the risk before and after mitigation measure implementation), were then used to identify the most cost-effective approaches to vapor cloud mitigation

VAPOR MIXER FOR GELATINIZATION OF STARCH IN LIQUEFYING STATION

Directory of Open Access Journals (Sweden)

V. V. Ananskikh

2015-01-01

Full Text Available Starch hydrolysis is main technological process in production of starch sweeteners. Acid hydrolysis of starch using hydrochloric acid is carried out very fast but it does not allow to carry out full hydrolysis and to produce products with given carbohydrate composition. Bioconversion of starch allows to eliminate these limitations. At production of starch sweeteners from starch using enzymes starch hydrolysis is carried out in two stages At first starch – starch liquefaction the rapid increase of viscosity takes place which requires intensive mixing. Liquefying station consists of jet-cooker, holder, pressure regulator and evaporator. Jet-cooker of starch is its main part, starch is quickly turns into soluble (gelatinized state and it is partially liquefied by injection of starch suspension by flow of water vapor under pressure not less than 0,8 MPa. Heat and hydraulic calculation were carried out in order to determine constructive sizes of mixer for cooking of starch. The main hydraulic definable parameters are pressure drop in mixer, vapor pressure at mixer inlet, daily capacity of station by glucose syrup M, product consumption (starch suspension, diameter of inlet section of vapor nozzle. The goal of calculation was to determine vapor consumption M1, diameter d2 of outlet section of confuser injector, length l2 of gelatinization section. For heat calculation there was used Shukhov’s formula along with heat balance equation for gelatinization process. The numerical solution obtained with adopted assumptions given in applied mathematical package MATHCAD, for M = 50 t/day gives required daily vapor consumption M1 = 14,446 т. At hydraulic calculation of pressure drop in mixer there was used Bernoulli’s theorem. Solving obtained equations using MATHCAD found diameter of outlet section of consufer d2 = 0,023 м, vapor pressure inside of mixer p2 = 3,966·105 Па, l2 = 0,128 м. Developed method of calculation is used to determine

The thermodynamic characteristics of vaporization of praseodymium triiodide

Science.gov (United States)

Motalov, V. B.; Kudin, L. S.; Markus, T.

2009-03-01

The vaporization of praseodymium triiodide was studied by high-temperature mass spectrometry. Monomeric (PrI3) and dimeric (Pr2I6) molecules and the PrI{4/-} and Pr2I{7/-} negative ions were recorded in saturated vapor over the temperature range 842-1048 K. The partial pressures of neutral vapor components were determined. The enthalpies of sublimation Δs H o(298.15 K) in the form of monomers (291 ± 10 kJ/mol) and dimers (400 ± 30 kJ/mol) were calculated by the second and third laws of thermodynamics. The equilibrium constants of ion-molecular reactions were measured and the enthalpies of the reactions determined. The enthalpies of formation Δf H o(298.15 K) of molecules and ions in the gas phase were calculated (-373 ± 11, -929 ± 31, -865 ± 25, and -1433 ± 48 kJ/mol for PrI3, Pr2I6, PrI{4/-}, and Pr2I{7/-}, respectively).

Dynamic Leidenfrost temperature on micro-textured surfaces: Acoustic wave absorption into thin vapor layer

Science.gov (United States)

Jerng, Dong Wook; Kim, Dong Eok

2018-01-01

The dynamic Leidenfrost phenomenon is governed by three types of pressure potentials induced via vapor hydrodynamics, liquid dynamic pressure, and the water hammer effect resulting from the generation of acoustic waves at the liquid-vapor interface. The prediction of the Leidenfrost temperature for a dynamic droplet needs quantitative evaluation and definition for each of the pressure fields. In particular, the textures on a heated surface can significantly affect the vapor hydrodynamics and the water hammer pressure. We present a quantitative model for evaluating the water hammer pressure on micro-textured surfaces taking into account the absorption of acoustic waves into the thin vapor layer. The model demonstrates that the strength of the acoustic flow into the liquid droplet, which directly contributes to the water hammer pressure, depends on the magnitude of the acoustic resistance (impedance) in the droplet and the vapor region. In consequence, the micro-textures of the surface and the increased spacing between them reduce the water hammer coefficient ( kh ) defined as the ratio of the acoustic flow into the droplet to total generated flow. Aided by numerical calculations that solve the laminar Navier-Stokes equation for the vapor flow, we also predict the dynamic Leidenfrost temperature on a micro-textured surface with reliable accuracy consistent with the experimental data.

Diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream

Science.gov (United States)

Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji Hyung; Parks, II, James E.

2017-12-26

A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.

Effect of interfacial turbulence and accommodation coefficient on CFD predictions of pressurization and pressure control in cryogenic storage tank

Science.gov (United States)

Kassemi, Mohammad; Kartuzova, Olga

2016-03-01

Pressurization and pressure control in cryogenic storage tanks are to a large extent affected by heat and mass transport across the liquid-vapor interface. These mechanisms are, in turn, controlled by the kinetics of the phase change process and the dynamics of the turbulent recirculating flows in the liquid and vapor phases. In this paper, the effects of accommodation coefficient and interfacial turbulence on tank pressurization and pressure control simulations are examined. Comparison between numerical predictions and ground-based measurements in two large liquid hydrogen tank experiments, performed in the K-site facility at NASA Glenn Research Center (GRC) and the Multi-purpose Hydrogen Test Bed (MHTB) facility at NASA Marshall Space Flight Center (MSFC), are used to show the impact of accommodation coefficient and interfacial and vapor phase turbulence on evolution of pressure and temperatures in the cryogenic storage tanks. In particular, the self-pressurization comparisons indicate that: (1) numerical predictions are essentially independent of the magnitude of the accommodation coefficient; and (2) surprisingly, laminar models sometimes provide results that are in better agreement with experimental self-pressurization rates, even in parametric ranges where the bulk flow is deemed fully turbulent. In this light, shortcomings of the present CFD models, especially, numerical treatments of interfacial mass transfer and turbulence, as coupled to the Volume-of-Fluid (VOF) interface capturing scheme, are underscored and discussed.

Relating tropical ocean clouds to moist processes using water vapor isotope measurements

Directory of Open Access Journals (Sweden)

J. Lee

2011-01-01

Full Text Available We examine the co-variations of tropospheric water vapor, its isotopic composition and cloud types and relate these distributions to tropospheric mixing and distillation models using satellite observations from the Aura Tropospheric Emission Spectrometer (TES over the summertime tropical ocean. Interpretation of these process distributions must take into account the sensitivity of the TES isotope and water vapor measurements to variations in cloud, water, and temperature amount. Consequently, comparisons are made between cloud-types based on the International Satellite Cloud Climatology Project (ISSCP classification; these are clear sky, non-precipitating (e.g., cumulus, boundary layer (e.g., stratocumulus, and precipitating clouds (e.g. regions of deep convection. In general, we find that the free tropospheric vapor over tropical oceans does not strictly follow a Rayleigh model in which air parcels become dry and isotopically depleted through condensation. Instead, mixing processes related to convection as well as subsidence, and re-evaporation of rainfall associated with organized deep convection all play significant roles in controlling the water vapor distribution. The relative role of these moisture processes are examined for different tropical oceanic regions.

Phase equilibrium measurements of (methane + benzene) and (methane + methylbenzene) at temperatures from (188 to 348) K and pressures to 13 MPa

International Nuclear Information System (INIS)

Hughes, Thomas J.; Kandil, Mohamed E.; Graham, Brendan F.; Marsh, Kenneth N.; Huang, Stanley H.; May, Eric F.

2015-01-01

Highlights: • VLE data for (CH 4 (1) + C 6 H 6 (2)) and (CH 4 (1) + C 6 H 5 CH 3 (3)) were measured. • LLE was observed at T = 198.15 K, a T higher than expected, for (CH 4 + C 6 H 5 CH 3 ) . • Inconsistences in the literature data were identified and assessed. • More data at x 1 > 0.3 for both systems are needed to investigate discrepancies. - Abstract: New isothermal pTxy data are reported for (methane + benzene) and (methane + methylbenzene (toluene)) at pressures up to 13 MPa over the temperature range (188 to 313) K using a custom-built (vapor + liquid) equilibrium (VLE) apparatus. The aim of this work was to investigate literature data inconsistencies and to extend the measurements to lower temperatures. For (methane (1) + benzene (2)), measurements were made along six isotherms from (233 to 348) K at pressures to 9.6 MPa. At temperatures below 279 K there was evidence of a solid phase, and thus only vapor phase samples were analyzed at these temperatures. For the (methane (1) + methylbenzene (3)) system, measurements were made along seven isotherms from T = (188 to 313) K at pressures up to 13 MPa. Along the 198 K isotherm, a significant change in the data’s p,x slope was observed indicating (liquid + liquid) equilibria at higher pressures. The data were compared with literature data and with calculations made using the Peng–Robinson (PR) equation of state (EOS). For both binary systems our data agree with much of the literature data that also deviate from the EOS in a similar manner. However, the data of Elbishlawi and Spencer (1951) for both binary systems, which appear to have received an equal weighting to other data in the EOS development, are inconsistent with the results of our measurements and data from other literature sources

Measurements of the vapor-liquid coexistence curve and the critical parameters for 1,1,1,2-tetrafluoroethane

Science.gov (United States)

Kabata, Y.; Tanikawa, S.; Uematsu, M.; Watanabe, K.

1989-05-01

Measurements of the vapor-liquid coexistence curve in the critical region for 1,1,1,2-tetrafluoroethane (R134a; CH2FCF3), which is currently considered as a prospective substitute for conventional refrigerant R12, have been performed by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Twenty-seven saturated densities along the vapor-liquid coexistence curve between 208 and 999 kg·m-3 have been obtained in the temperature range 343 K to the critical temperature. The experimental uncertainties in temperature and density measurements have been estimated to be within ±10mK and ±0.55%, respectively. On the basis of these measurements near the critical point, the critical temperature and the critical density for 1,1,1,2-tetrafluoroethane were determined in consideration of the meniscus disappearing level as well as the intensity of the critical opalescence. In addition, the critical exponent ß along the vapor-liquid coexistence curve has been determined in accord with the difference between the density of the saturated liquid and that of the saturated vapor.

Uranium isotope fractionation resulting from UF6 vapor distillation from containers

International Nuclear Information System (INIS)

Hedge, W.D.; Turner, C.M.

1985-01-01

This empirical study for possible isotopic fractionation due to UF 6 vapor distillation from valved containers was performed to determine the effects of repeated vapor sampling. Four different experiments were performed, each of which varied by the method of measuring the isotopic contents and/or by the difference in temperature gradients as follows: The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen temperature and homogenized was measured by sampling the containers. The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen temperature and homogenized was measured by direct comparison to each other without subsampling. The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen and ice-water temperatures and homogenized was measured by indirect comparison to a common UF 6 reference material without subsampling. The ratio of the parent UF 6 to the desublimed UF 6 collected at liquid nitrogen temperature without homogenizing was measured by indirect comparison to a common UF 6 reference. Gas-phase, relative mass spectrometry was used for all isotopic measurements. Results of the study indicate that fractionation does occur. The U-235 isotope becomes more enriched in the parent container as the UF 6 is vaporized from it and desublimed into the receiving cylinder; i.e., the vaporized fraction is enriched in the U-238 isotope. The degree of fractionation indicates that the separation is due to the U-238 isotope of UF 6 having a higher vapor pressure than the U-235 isotope of UF 6 . 3 refs., 4 figs., 4 tabs

Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach

Science.gov (United States)

Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

2013-01-01

Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

Conductivity of cesium-seeded atmospheric pressure plasmas near thermal equilibrium

Energy Technology Data Exchange (ETDEWEB)

Harris, L. P.

1963-04-15

Measurements were made of the electric conductivities of gaseous mixtures formed by the addition of small fractions of cesium vapor to nitrogen, helium, neon, or argon. The mixtures studied were maintained near thermal equilibrium at temperatures in the 1500 to 2000 deg K range and a total pressure of 1 atm. The cesium vapor pressures ranged over two decades, from 0.1 to 10 torr. The apparatus consists, in essence, of two heated zones connected by a slow flow. The first zone is a low-temperature (200 to 400 deg C) oven where the body-gas flow picks up the cesium vapor. The second zone is a small electrically heated furnace (1250 to 1850 deg C) containing a diode test section. The principal measurements taken were the seeding temperature, furnace temperature, and voltages and currents in the test section. The results exhibit variations with temperature, seeding pressure, and gas species that correlate reasonably well with simple theory and values for electron collision frequencies and cross sections taken from the literature. (auth)

Low temperature carrier transport study of monolayer MoS{sub 2} field effect transistors prepared by chemical vapor deposition under an atmospheric pressure