WorldWideScience

Sample records for reserve vapor pressure

  1. U.S. Strategic Petroleum Reserve Vapor Pressure Committee 2009 annual report.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Ray (Allen Energy Services, Inc., Longview, TX); Eldredge, Lisa (DynMcDermott Petroleum Operations, Harahan, LA); DeLuca, Charles (DynMcDermott Petroleum Operations, Harahan, LA); Mihalik, Patrick (DynMcDermott Petroleum Operations, Harahan, LA); Maldonado, Julio (U.S. Department of Energy, Harahan, LA); Lord, David L.; Rudeen, David Keith (GRAM, Inc., Albuquerque, NM); Berndsen, Gerard (U.S. Department of Energy, Harahan, LA)

    2010-05-01

    This report comprises an annual summary of activities under the U.S. Strategic Petroleum Reserve (SPR) Vapor Pressure Committee in FY2009. The committee provides guidance to senior project management on the issues of crude oil vapor pressure monitoring nd mitigation. The principal objectives of the vapor pressure program are, in the event of an SPR drawdown, to minimize the impact on the environment and assure worker safety and public health from crude oil vapor emissions. The annual report reviews key program areas ncluding monitoring program status, mitigation program status, new developments in measurements and modeling, and path forward including specific recommendations on cavern sampling for the next year. The contents of this report were first presented to SPR senior anagement in December 2009, in a deliverable from the vapor pressure committee. The current SAND report is an adaptation for the Sandia technical audience.

  2. 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.

  3. The vapor pressures of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

    2013-01-05

    The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

  4. Estimating pure component vapor pressures

    Energy Technology Data Exchange (ETDEWEB)

    Myrdal, P.B.; Yalkowsky, S.H. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Pharmaceutical Sciences

    1994-12-31

    The hazard of exposure to volatile organic compounds is an increasing concern all chemical industries. Recent EPA and FDA guidelines require the environmental assessment of new chemical entities, which includes the determination or estimation of vapor pressure. This work presents a means for the reliable estimation of pure component vapor pressures. The method presented is an extension of the work proposed by Mishra and Yalkowsky. New equations are presented for the heat capacity change upon boiling and the entropy of boiling. The final vapor pressure equation requires only the knowledge of transition temperatures and molecular structure. The equation developed has been successfully applied to 296 organic compounds, giving an overall average absolute error of 0.12 log units (in atm. at 25 C). In addition, the equation is shown to be very accurate in predicting vapor pressure as a function of temperature. However, for many compounds of environmental interest, the boiling point is not known or cannot be determined due to decomposition. In light of this, a new technique has been developed which can be used to estimate ``hypothetical`` boiling points. This enables the estimation of vapor pressure from as little as one transition temperature and molecular structure.

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

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

  7. Vapor Pressure Data Analysis and Statistics

    Science.gov (United States)

    2016-12-01

    SUBJECT TERMS Vapor pressure Antoine equation Statistical analysis Clausius–Clapeyron equation Standard deviation Volatility Enthalpy of volatilization...11 5. Antoine Constants (Equation 3), Standard Deviations , and S for 1-Tetradecanol .............12 6. Vapor...13 7. Antoine Constants (Equation 3), Standard Deviations , and S for DEM ............................13 8. Vapor Pressures

  8. Thermogravimetric measurements of liquid vapor pressure

    International Nuclear Information System (INIS)

    Rong Yunhong; Gregson, Christopher M.; Parker, Alan

    2012-01-01

    Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

  9. 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

  10. 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,

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

    Science.gov (United States)

    Mbah, Jonathan; Knott, Debra; Steward, Scott

    2014-11-01

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

  12. Vapor Pressure of 2-Chlorovinyl Dichloroarsine (Lewisite)

    Science.gov (United States)

    2009-02-01

    Woodward, and Owens investigated the vapor pressures of arsenic trichloride and Lewisite I in a study covering the range 50 to 150 °C.10 In 1944...Interaction with Benzene in the Presence of Aluminum Chloride. Production of 9:10-Di-methylanthracene. J. Chem. Soc. 1931,753. 9. Klosky, S.; Strieker

  13. 40 CFR 796.1950 - Vapor pressure.

    Science.gov (United States)

    2010-07-01

    ... combined with water solubility data permit the calculation of Henry's law constant, a parameter essential...) “Pascal” (Pa) is the standard international unit of vapor pressure and is defined as newtons per square meter (N/m2). A newton is the force necessary to give acceleration of one meter per second squared to...

  14. A predictive vapor-pressure equation

    International Nuclear Information System (INIS)

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

    2008-01-01

    A simple equation is presented for predicting the temperature dependence of the vapor-pressure of a pure substance along the entire (liquid + vapor) coexistence curve, from the triple point to the critical point. The proposed equation is based on the use of a dimensionless temperature reduced by using critical and triple point values, and of the Clausius-Clapeyron equation as a zeroth-order approximation. The pressure and temperature at the triple point, the normal boiling temperature, and the pressure and temperature at the critical point are required as input data. The proposed equation is verified for 53 fluids by using NIST data. These data are reproduced with an overall average deviation of 0.55%

  15. 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

  16. 46 CFR 154.451 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.451 Section 154.451 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Independent Tank Type C and Process Pressure Vessels § 154.451 Design vapor pressure. The Po (kPa) of an...

  17. Vapor Pressure of Methyl Salicylate and n-Hexadecane

    Science.gov (United States)

    2014-01-01

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

  18. 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.

  19. Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

    International Nuclear Information System (INIS)

    Emel'yanenko, Vladimir N.; Portnova, Svetlana V.; Verevkin, Sergey P.; Skrzypczak, Andrzej; Schubert, Thomas

    2011-01-01

    Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C 3 , C 5 -C 7 , and C 9 -C 10 . → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C 3 , C 5 -C 7 , and C 9 -C 10 have been measured by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization Δ l g H m (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

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

    OpenAIRE

    Kanatani, Kentaro

    2008-01-01

    We study an instability of thin liquid-vapor layers bounded by rigid parallel walls from both below and above. In this system, the interfacial instability is induced by lateral vapor pressure fluctuation, which is in turn attributed to the effect of phase change: evaporation occurs at a hotter portion of the interface and condensation at a colder one. The high vapor pressure pushes the interface downward and the low one pulls it upward. A set of equations describing the temporal evolution of ...

  1. Determination of Cannabinoid Vapor Pressures to Aid in Vapor Phase Detection of Intoxication.

    Science.gov (United States)

    Lovestead, Tara M; Bruno, Thomas J

    2017-09-01

    The quest for a reliable means to detect cannabis intoxication with a breathalyzer is ongoing. To design such a device, it is important to understand the fundamental thermodynamics of the compounds of interest. The vapor pressures of two important cannabinoids, cannabidiol (CBD) and Δ 9 -tetrahydrocannabinol (Δ 9 -THC), are presented, as well as the predicted normal boiling temperature (NBT) and the predicted critical constants (these predictions are dependent on the vapor pressure data). The critical constants are typically necessary to develop an equation of state (EOS). EOS-based models can provide estimations of thermophysical properties for compounds to aid in designing processes and devices. An ultra-sensitive, quantitative, trace dynamic headspace analysis sampling called porous layered open tubular-cryoadsorption (PLOT-cryo) was used to measure vapor pressures of these compounds. PLOT-cryo affords short experiment durations compared to more traditional techniques for vapor pressure determination (minutes versus days). Additionally, PLOT-cryo has the inherent ability to stabilize labile solutes because collection is done at reduced temperature. The measured vapor pressures are approximately 2 orders of magnitude lower than those measured for n-eicosane, which has a similar molecular mass. Thus, the difference in polarity of these molecules must be impacting the vapor pressure dramatically. The vapor pressure measurements are presented in the form of Clausius-Clapeyron (or van't Hoff) equation plots. The predicted vapor pressures that would be expected at near ambient conditions (25 °C) are also presented.

  2. 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

  3. 46 CFR 154.445 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.445 Section 154.445 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Independent Tank Type B § 154.445 Design vapor pressure. If the surfaces of an independent tank type B are...

  4. 46 CFR 154.438 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.438 Section 154.438 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Independent Tank Type A § 154.438 Design vapor pressure. (a) If the surface of an independent tank type A are...

  5. 46 CFR 154.426 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.426 Section 154.426 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Tanks § 154.426 Design vapor pressure. The Po of a membrane tank must not exceed 24.5 kPa gauge (3.55...

  6. 46 CFR 154.436 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure. 154.436 Section 154.436 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS...-Membrane Tanks § 154.436 Design vapor pressure. The Po of a semi-membrane tank must not exceed 24.5 kPa...

  7. Prospective Chemistry Teachers' Mental Models of Vapor Pressure

    Science.gov (United States)

    Tumay, Halil

    2014-01-01

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

  8. The vapor pressure over nano-crystalline ice

    Directory of Open Access Journals (Sweden)

    M. Nachbar

    2018-03-01

    Full Text Available The crystallization of amorphous solid water (ASW is known to form nano-crystalline ice. The influence of the nanoscale crystallite size on physical properties like the vapor pressure is relevant for processes in which the crystallization of amorphous ices occurs, e.g., in interstellar ices or cold ice cloud formation in planetary atmospheres, but up to now is not well understood. Here, we present laboratory measurements on the saturation vapor pressure over ice crystallized from ASW between 135 and 190 K. Below 160 K, where the crystallization of ASW is known to form nano-crystalline ice, we obtain a saturation vapor pressure that is 100 to 200 % higher compared to stable hexagonal ice. This elevated vapor pressure is in striking contrast to the vapor pressure of stacking disordered ice which is expected to be the prevailing ice polymorph at these temperatures with a vapor pressure at most 18 % higher than that of hexagonal ice. This apparent discrepancy can be reconciled by assuming that nanoscale crystallites form in the crystallization process of ASW. The high curvature of the nano-crystallites results in a vapor pressure increase that can be described by the Kelvin equation. Our measurements are consistent with the assumption that ASW is the first solid form of ice deposited from the vapor phase at temperatures up to 160 K. Nano-crystalline ice with a mean diameter between 7 and 19 nm forms thereafter by crystallization within the ASW matrix. The estimated crystal sizes are in agreement with reported crystal size measurements and remain stable for hours below 160 K. Thus, this ice polymorph may be regarded as an independent phase for many atmospheric processes below 160 K and we parameterize its vapor pressure using a constant Gibbs free energy difference of 982  ±  182 J mol−1 relative to hexagonal ice.

  9. 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.

    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

  10. 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

  11. Computation of Equilibrium Partial Vapor Pressures of Aqueous Ammonia Solutions

    National Research Council Canada - National Science Library

    Field, Paul

    2000-01-01

    This report evaluates all available vapor-liquid equilibria (VLE) data from low-to-moderate pressures over the normal liquid water temperature range for the highly non-ideal aqueous ammonia solutions spanning nearly a century...

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

    Science.gov (United States)

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

    2017-10-01

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

  13. 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.

  14. 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.

  15. 46 CFR 30.10-59 - Reid vapor pressure-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Reid vapor pressure-TB/ALL. 30.10-59 Section 30.10-59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-59 Reid vapor pressure—TB/ALL. The term Reid vapor pressure means the vapor pressure of a liquid at a...

  16. Bibliography on vapor pressure isotope effects

    International Nuclear Information System (INIS)

    Jancso, G.

    1980-04-01

    The first Bibliography on Vapour Pressure Isotope and covered the literature of the period from 1919 through December 1975. The present Supplement reviews the literature from January 1976 through December 1979. The bibliography is arranged in chronological order; within each year the references are listed alphabetically according to the name of the first author of each work. (author)

  17. 46 CFR 154.419 - Design vapor pressure.

    Science.gov (United States)

    2010-10-01

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

  18. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    DEFF Research Database (Denmark)

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

    are allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using...

  19. 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

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

    Science.gov (United States)

    2016-02-01

    concentrations for quantitative toxicology evaluations and detector testing as well as the prediction of chemical removal efficiency by air filtration...systems. Vapor pressure data can also be useful for estimating the concentration of solution mixtures by quantitative analysis of head space. This...the partial pressures of the DICDI (Panalyte) and the nitrogen carrier gas (Pcarrier); na is moles of analyte, determined gravimetrically ; and ncar is

  1. Measurement of vapor pressure of organophosphorous compounds by gas chromatography

    International Nuclear Information System (INIS)

    Panneerselvam, K.; Brahmmananda Rao, C.V.S.; Antony, M.P.

    2016-01-01

    Dialkylalkyl phosphonates have been developed as an alternative solvent to TBP at our laboratory for separation of actinides. Several dialkylalkylphosphonates have been synthesized and the vapor pressure of all of them was determined using Gas Chromatography (GC) technique. In this technique, individual dialkylalkylphosphonates have been separated from a mixture using GC. Gas chromatography has been utilized as a successful technique in determining vapor pressure of homologous series and structurally similar compounds. GC retention time (t a ) is inversely proportional to the vapor pressure of the solute in solution of the stationary phase. This technique strongly depends on the linear correlation observed between 1n(p/p 0 ) of a reference compound and a target sample under investigation, where p is the vapor pressure for reference compound, p 0 = 101.325 kPa, and 1n(t 0 /t a ) where t 0 = 1 minute and t a = difference in retention times of the target compound and a nonretained compound, CH 2 Cl 2 , added. The retention time of reference (trialkyl phosphate) and target (dibutylalkyl phosphonates) compounds along with CH 2 Cl 2 has been obtained by gas chromatograph using a 4 m 10 % XE-60 packed column under isothermal conditions. Helium was used as carrier gas. As expected, the vapor pressure of reference as well as target compounds decreases with increasing molecular weight of organophosphorous compounds. The merits of this technique are its speed, accuracy and tiny volume of sample. Requirement of high purity sample in contrast to the conventional technique is also done away with this technique. (author)

  2. When Does Vapor Pressure Deficit Drive or Reduce Evaporation?

    Science.gov (United States)

    Massmann, A.; Gentine, P.; Lin, C.

    2017-12-01

    Depending on plant response (e.g. stomatal closure), ecosystem-scale evaporation can either increase or decrease with changes in vapor pressure deficit. This ecosystem response drives evaporation and atmospheric moisture feedbacks. We use data from 75 FluxNet sites within a Penman-Monteith framework to examine when ecosystem evaporation is suppressed or enhanced by increases in vapor pressure deficit. Evaporation response is quantified as a function of soil moisture, atmospheric conditions, and plant functional type. Uncertainty in plant response is accounted for by varying the stomatal resistance model and its parameters. This in-situ observation-based analysis aids understanding for how ecosystems will respond and/or contribute to future shifts in atmospheric water demand.

  3. 40 CFR 60.482-4a - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 60.482-4a Section 60.482-4a Protection of Environment ENVIRONMENTAL PROTECTION... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions, as indicated by an...

  4. 40 CFR 63.165 - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 63.165 Section 63.165 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with an instrument reading of less than 500 parts...

  5. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions, as indicated by an instrument...

  6. 40 CFR 60.482-4 - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 60.482-4 Section 60.482-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., 2006 § 60.482-4 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions...

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

    Science.gov (United States)

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

    2018-02-01

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

  8. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions, as indicated by an instrument...

  9. 40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 61.242-4 Section 61.242-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions, as indicated by an instrument reading of...

  10. 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

  11. 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

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

    Science.gov (United States)

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

    2017-12-01

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

  13. 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

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

    Science.gov (United States)

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

    2016-01-01

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

  15. 40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

    Science.gov (United States)

    2010-07-01

    ... gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...: Pressure relief devices in gas/vapor service. (a) Compliance schedule. The owner or operator shall comply... device in gas/vapor service shall be operated with an instrument reading of less than 500 parts per...

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

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Gauges and vapor return for cargo vapor pressures... COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.372 Gauges and vapor... section, the containment system must have a: (a) Tank pressure gauge at the point where cargo flow is...

  17. 46 CFR 154.405 - Design vapor pressure (Po) of a cargo tank.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Design vapor pressure (Po) of a cargo tank. 154.405... CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment Systems § 154.405 Design vapor pressure (Po) of a cargo tank. (a) The design...

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

    Science.gov (United States)

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

    2018-01-01

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

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

    Science.gov (United States)

    Winzor, Donald J

    2004-02-15

    As a response to recent expression of concern about possible unreliability of vapor pressure deficit measurements (K. Kiyosawa, Biophys. Chem. 104 (2003) 171-188), the results of published studies on the temperature dependence of the osmotic pressure of aqueous polyethylene glycol solutions are shown to account for the observed discrepancies between osmolality estimates obtained by freezing point depression and vapor pressure deficit osmometry--the cause of the concern.

  20. Vapor Pressure Data Analysis and Correlation Methodology for Data Spanning the Melting Point

    Science.gov (United States)

    2013-10-01

    specimen is adequately degassed, the liquid menisci in the U-tube are brought to the same level and the pressure read on the manometer . The measurement...VAPOR PRESSURE DATA ANALYSIS AND CORRELATION METHODOLOGY FOR DATA SPANNING THE MELTING POINT ECBC-CR-135 David E...REPORT TYPE Final 3. DATES COVERED (From - To) Mar 2013 - June 2013 4. TITLE AND SUBTITLE Vapor Pressure Data Analysis and Correlation Methodology

  1. 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

  2. 46 CFR 39.20-13 - High and low vapor pressure protection for tankships-T/ALL.

    Science.gov (United States)

    2010-10-01

    ... VAPOR CONTROL SYSTEMS Design and Equipment § 39.20-13 High and low vapor pressure protection for... system; and (3) Alarms at a low pressure of not less than four inches water gauge (0.144 psig) for an... 46 Shipping 1 2010-10-01 2010-10-01 false High and low vapor pressure protection for tankships-T...

  3. Optimal Approaches for Measuring Tongue-Pressure Functional Reserve

    Directory of Open Access Journals (Sweden)

    Catriona M. Steele

    2013-01-01

    Full Text Available Tongue-palate pressure is a parameter of considerable interest in the field of dysphagia. Maximum isometric tongue-palate pressures (MIPs decline in healthy aging and in dysphagia. Functional reserve (FR is the difference between MIPs and swallowing pressures. Reduced FR is thought to constitute a risk for developing functional swallowing impairments. We compare different approaches for calculating FR and recommend an optimal approach. Tongue-palate pressure data were collected from 78 healthy adults (4060 during anterior and posterior MIPs, regular (RESS and effortful (ESS saliva swallows, and water swallows (4 repetitions per task. Six different measures of reserve were calculated using maximum anterior MIPs or ESS pressures at the top, and mean or maximum RESS or water swallow pressures at the bottom of the range. Correlations with age and MIPs were explored to confirm suitability for measuring FR. The impact of normalization to maximum MIP range was explored. We conclude that an optimal measure of FR involves the comparison of maximum MIP with mean saliva swallowing pressures. This parameter declines with age, but when normalized to an individual’s MIP range, the relationship is no longer evident. This suggests that FR does not necessarily decline in healthy aging.

  4. 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...... databank (2036 values) composed by fatty compounds, i.e., fatty acids, methyl-, ethyl-, propyl- and butyl- esters, fatty alcohols, tri-, di- and monoacylglycerols and hydrocarbons. This new methodology gives improved predictions when compared to a prior group contribution equation (Ceriani and Meirelles...

  5. 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

  6. New expressions to describe solution nonideal osmotic pressure, freezing point depression, and vapor pressure.

    Science.gov (United States)

    Fullerton, G D; Zimmerman, R J; Cantu, C; Cameron, I L

    1992-12-01

    New empirical expressions for osmotic pressure, freezing point depression, and vapor pressure are proposed based on the concepts of volume occupancy and (or) hydration force. These expressions are in general inverse relationships in comparison to the standard ideal expressions for the same properties. The slopes of the new equations are determined by the molecular weight of the solute and known constants. The accuracy and precision of the molecular weights calculated from the slope are identical and approximately 1% for the experiments reported here. The nonideality of all three colligative expressions is described by a dimensionless constant called the solute-solvent interaction parameter I. The results on sucrose have the same I = 0.26 for all three solution properties. The nonideality parameter I increased from 0.26 on sucrose to 1.7 on hemoglobin to successfully describe the well-known nonideal response of macromolecules.

  7. Vapor Pressure of Hexamethylene Triperoxide Diamine (HMTD) Estimated Using Secondary Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Aernecke, Matthew J; Mendum, Ted; Geurtsen, Geoff; Ostrinskaya, Alla; Kunz, Roderick R

    2015-11-25

    A rapid method for vapor pressure measurement was developed and used to derive the vapor pressure curve of the thermally labile peroxide-based explosive hexamethylene triperoxide diamine (HMTD) over the temperature range from 28 to 80 °C. This method uses a controlled flow of vapor from a solid-phase HMTD source that is presented to an ambient-pressure-ionization mass spectrometer equipped with a secondary-electrospray-ionization (SESI) source. The subpart-per-trillion sensitivity of this system enables direct detection of HMTD vapor through an intact [M + H](+) ion in real time at temperatures near 20 °C. By calibrating this method using vapor sources of cocaine and heroin, which have known pressure-temperature (P-T) curves, the temperature dependence of HMTD vapor was determined, and a Clausius-Clapeyron plot of ln[P (Pa)] vs 1/[T (K)] yielded a straight line with the expression ln[P (Pa)] = {(-11091 ± 356) × 1/[T (K)]} + 25 ± 1 (error limits are the standard error of the regression analysis). From this equation, the sublimation enthalpy of HMTD was estimated to be 92 ± 3 kJ/mol, which compares well with the theoretical estimate of 95 kJ/mol, and the vapor pressure at 20 °C was estimated to be ∼60 parts per trillion by volume, which is within a factor of 2 of previous theoretical estimates. Thus, this method provides not only the first direct experimental determination of HMTD vapor pressure but also a rapid, near-real-time capability to quantitatively measure low-vapor-pressure compounds, which will be useful for aiding in the development of training aids for bomb-sniffing canines.

  8. Modeling chemical vapor deposition of silicon dioxide in microreactors at atmospheric pressure

    NARCIS (Netherlands)

    Konakov, S.A.; Krzhizhanovskaya, V.V.

    2015-01-01

    We developed a multiphysics mathematical model for simulation of silicon dioxide Chemical Vapor Deposition (CVD) from tetraethyl orthosilicate (TEOS) and oxygen mixture in a microreactor at atmospheric pressure. Microfluidics is a promising technology with numerous applications in chemical synthesis

  9. 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.

  10. Indoor/outdoor connections exemplified by processes that depend on an organic compound's saturation vapor pressure

    DEFF Research Database (Denmark)

    Weschler, Charles J.

    2003-01-01

    Outdoor and indoor environments are profitably viewed as parts of a whole connected through various physical and chemical interactions. This paper examines four phenomena that share a dependence on vapor pressure-the extent to which an organic compound in the gas phase sorbs on airborne particles......'s saturation vapor pressure correlates in a linear fashion with the logarithms of equilibrium coefficients characteristic of each of these four phenomena. Since, to a rough approximation, the log of an organic compound's vapor pressure scales with its molecular weight, molecular weight can be used to make...... first estimates of the above processes. For typical indoor conditions, only larger compounds with lower-saturation vapor pressures (e.g., tetracosane, pentacosane, or di-2-ethylhexyl phthalate) have airborne particle concentrations comparable to or larger than gas phase concentrations. Regardless...

  11. 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

  12. 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

  13. 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.

  14. A new approach to determine vapor pressures of compounds in multicomponent systems by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.

    Science.gov (United States)

    Parshintsev, Jevgeni; Lai, Ching Kwan; Hartonen, Kari; Kulmala, Markku; Riekkola, Marja-Liisa

    2014-06-01

    A method is described to determine vapor pressures of compounds in multicomponent systems simultaneously. The method is based on temperature-gradient analysis by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS). Vapor pressures are determined with the aid of known vapor pressure values of reference compounds eluting before and after the analytes. Reference compounds with the same functionalities as the analytes are preferred, but when these are not available, the alkane series can be utilized. The number of compounds whose vapor pressures can be determined is limited only by the peak capacity of the chromatographic system. Although the lowest subcooled vapor pressure determined was 0.006 Pa, for tetrahydroaraucarolone in an atmospheric aerosol sample, vapor pressures as low as 10(-6) Pa can be measured with the described set-up. Even lower values can be measured with higher GC temperatures and longer analysis times. Since only a few picograms of compound is required, in a mixture of any complexity, the GCxGC-TOFMS method offers unique sensitivity, rapidity, and comprehensiveness. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Integrated Rig for the Production of Boron Nitride Nanotubes via the Pressurized Vapor-Condenser Method

    Science.gov (United States)

    Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor)

    2014-01-01

    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

  16. Observations on vapor pressure in SPR caverns : sources.

    Energy Technology Data Exchange (ETDEWEB)

    Munson, Darrell Eugene

    2010-05-01

    The oil of the Strategic Petroleum Reserve (SPR) represents a national response to any potential emergency or intentional restriction of crude oil supply to this country, and conforms to International Agreements to maintain such a reserve. As assurance this reserve oil will be available in a timely manner should a restriction in supply occur, the oil of the reserve must meet certain transportation criteria. The transportation criteria require that the oil does not evolve dangerous gas, either explosive or toxic, while in the process of transport to, or storage at, the destination facility. This requirement can be a challenge because the stored oil can acquire dissolved gases while in the SPR. There have been a series of reports analyzing in exceptional detail the reasons for the increases, or regains, in gas content; however, there remains some uncertainty in these explanations and an inability to predict why the regains occur. Where the regains are prohibitive and exceed the criteria, the oil must undergo degasification, where excess portions of the volatile gas are removed. There are only two known sources of gas regain, one is the salt dome formation itself which may contain gas inclusions from which gas can be released during oil processing or storage, and the second is increases of the gases release by the volatile components of the crude oil itself during storage, especially if the stored oil undergoes heating or is subject to biological generation processes. In this work, the earlier analyses are reexamined and significant alterations in conclusions are proposed. The alterations are based on how the fluid exchanges of brine and oil uptake gas released from domal salt during solutioning, and thereafter, during further exchanges of fluids. Transparency of the brine/oil interface and the transfer of gas across this interface remains an important unanswered question. The contribution from creep induced damage releasing gas from the salt surrounding the cavern is

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-04-01

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

  19. 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...

  20. Chemical vapor deposition of graphene at very low pressures

    OpenAIRE

    Thiago Henrique Rodrigues da Cunha

    2014-01-01

    A deposição química de vapor (CVD) de hidrocarbonetos vem se tornando um paradigma para a produção de grafeno em larga escala. No entanto, os mecanismos de crescimento associados ao processo ainda não são totalmente compreendidos, de forma que ainda não é possível um controle sistemático da qualidade dos filmes sintetizados. Nesta tese, apresentamos uma investigação detalhada do crescimento de grafeno por CVD à baixa pressão em um reator de parede fria, utilizando substratos de cobre. Uma com...

  1. 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

  2. Experimental study of saturated vapor pressure and density of liquid phase of rubidium-cesium alloy

    International Nuclear Information System (INIS)

    Roshchupkin, V.V.; Pokrasin, M.A.; Chernov, A.I.

    1995-01-01

    Data of an experimental determination of rubidium-base liquid alloy density (72.4 mas.% of Rb + 27.6 mas.% of Cs), as well as of pressure of the indicated alloy saturated vapors are presented. Liquid phase density is measured by differential hydrostatic weighing method. The density measurement error at 1140 K temperature makes up 0.8%. Comparison of experimental and estimated data on the saturated vapor pressure has demonstrated a notable difference between them, which is some cases does not allow one to use data obtained by means of calculations. 4 refs.; 3 tabs

  3. 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)

  4. 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.

  5. Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions.

    Science.gov (United States)

    Kiyosawa, Keitaro

    2003-05-01

    For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit. Measurement of the osmotic pressure of plants under water stress has been mainly based on vapor pressure deficit. However, differences have been noted for osmotic pressure values of aqueous polyethylene glycol (PEG) solutions measured by freezing point depression and vapor pressure deficit. For this paper, the physicochemical basis of freezing point depression and vapor pressure deficit were first examined theoretically and then, the osmotic pressure of aqueous ethylene glycol and of PEG solutions were measured by both freezing point depression and vapor pressure deficit in comparison with other aqueous solutions such as NaCl, KCl, CaCl(2), glucose, sucrose, raffinose, and bovine serum albumin (BSA) solutions. The results showed that: (1) freezing point depression and vapor pressure deficit share theoretically the same physicochemical basis; (2) theoretically, they are proportional to the molal concentration of the aqueous solutions to be measured; (3) in practice, the osmotic pressure levels of aqueous NaCl, KCl, CaCl(2), glucose, sucrose, and raffinose solutions increase in proportion to their molal concentrations and there is little inconsistency between those measured by freezing point depression and vapor pressure deficit; (4) the osmotic pressure levels of aqueous ethylene glycol and PEG solutions measured by freezing point depression differed from the values measured by vapor pressure deficit; (5) the osmotic pressure of aqueous BSA solution measured by freezing point depression differed slightly from that measured by vapor pressure deficit.

  6. 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 * anilin e * nitromethane Subject RIV: BJ - Thermodynamics Impact factor: 1.846, year: 2015

  7. 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

  8. New Static Apparatus and Vapor Pressure of Reference Materials: Naphthalene, Benzoic Acid, Benzophenone, and Ferrocene

    Czech Academy of Sciences Publication Activity Database

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

    2006-01-01

    Roč. 51, - (2006), s. 757-766 ISSN 0021-9568 Grant - others:FCT(PT) POCTI/QUI/43144/2001; FEDER(PT) SFRH/ BPD /18065/2004 Institutional research plan: CEZ:AV0Z10100521 Keywords : vapor pressure * reference substance * thermochemistry * construction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.642, year: 2006

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

    Science.gov (United States)

    Goldfarb, Jillian L.

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (OPAHs) are ubiquitous environmental pollutants resulting from the incomplete combustion of coal and fossil fuels. Their vapor pressures are key thermodynamic data essential for modeling fate and transport within the environment. The present study involved nine PAHs containing oxygen heteroatoms, including aldehyde, carboxyl and nitro groups, specifically: 2-nitrofluorene; 9-fluorenecarboxylic acid; 2-fluorenecarboxaldehyde; 2-anthracenecarboxylic acid; 9-anthracenecarboxylic acid; 9-anthraldehyde; 1-nitropyrene; 1-pyrenecarboxaldehyde and 1-bromo-2-naphthoic acid. The vapor pressures of these compounds, with molecular weights ranging from 194 to 251 grams per mole, were measured using the isothermal Knudsen effusion technique in the temperature range of 329 to 421. The corresponding enthalpies of sublimation, calculated via the Clausius-Clapeyron equation, are compared to parent, non-oxygenated PAH compound data to determine the effect of the addition of these oxygen-containing heteroatoms. As expected, the addition of –CHO,–COOH, and –NO2 groups onto these PAHs increases the enthalpy of sublimation and decreases the vapor pressure as compared to the parent PAH; the position of substitution also plays a significant role in determining the vapor pressure of these OPAHs. PMID:18220445

  10. Vapor Pressure of Hexamethylene Triperoxide Diamine (HTMD) Determined with Secondary Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    2015-07-03

    rate constant for decomposition of 10-3 sec-1, three orders of magnitude higher than triacetone triperoxide ( TATP , 10-6 sec-1) with trimethylamine... TATP and diacetone diperoxide (DADP)) but only succeeded in assigning an upper limit on the vapor pressure of HMTD (0.04 Pa) [5]. The authors

  11. 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.

  12. 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

  13. 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.

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

    Science.gov (United States)

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

    2004-01-01

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

  15. 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

  16. The evolution of mechanisms driving the stomatal response to vapor pressure deficit.

    Science.gov (United States)

    McAdam, Scott A M; Brodribb, Timothy J

    2015-03-01

    Stomatal responses to vapor pressure deficit (VPD) are a principal means by which vascular land plants regulate daytime transpiration. While much work has focused on characterizing and modeling this response, there remains no consensus as to the mechanism that drives it. Explanations range from passive regulation by leaf hydration to biochemical regulation by the phytohormone abscisic acid (ABA). We monitored ABA levels, leaf gas exchange, and water status in a diversity of vascular land plants exposed to a symmetrical, mild transition in VPD. The stomata in basal lineages of vascular plants, including gymnosperms, appeared to respond passively to changes in leaf water status induced by VPD perturbation, with minimal changes in foliar ABA levels and no hysteresis in stomatal action. In contrast, foliar ABA appeared to drive the stomatal response to VPD in our angiosperm samples. Increased foliar ABA level at high VPD in angiosperm species resulted in hysteresis in the recovery of stomatal conductance; this was most pronounced in herbaceous species. Increased levels of ABA in the leaf epidermis were found to originate from sites of synthesis in other parts of the leaf rather than from the guard cells themselves. The transition from a passive regulation to ABA regulation of the stomatal response to VPD in the earliest angiosperms is likely to have had critical implications for the ecological success of this lineage. © 2015 American Society of Plant Biologists. All Rights Reserved.

  17. Limited-transpiration response to high vapor pressure deficit in crop species.

    Science.gov (United States)

    Sinclair, Thomas R; Devi, Jyostna; Shekoofa, Avat; Choudhary, Sunita; Sadok, Walid; Vadez, Vincent; Riar, Mandeep; Rufty, Thomas

    2017-07-01

    Water deficit under nearly all field conditions is the major constraint on plant yields. Other than empirical observations, very little progress has been made in developing crop plants in which specific physiological traits for drought are expressed. As a consequence, there was little known about under what conditions and to what extent drought impacts crop yield. However, there has been rapid progress in recent years in understanding and developing a limited-transpiration trait under elevated atmospheric vapor pressure deficit to increase plant growth and yield under water-deficit conditions. This review paper examines the physiological basis for the limited-transpiration trait as result of low plant hydraulic conductivity, which appears to be related to aquaporin activity. Methodology was developed based on aquaporin involvement to identify candidate genotypes for drought tolerance of several major crop species. Cultivars of maize and soybean are now being marketed specifically for arid conditions. Understanding the mechanism of the limited-transpiration trait has allowed a geospatial analyses to define the environments in which increased yield responses can be expected. This review highlights the challenges and approaches to finally develop physiological traits contributing directly to plant improvement for water-limited environments. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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 controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet 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.

  3. 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.

  4. 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.

  5. 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.

  6. Fast membrane osmometer as alternative to freezing point and vapor pressure osmometry.

    Science.gov (United States)

    Grattoni, Alessandro; Canavese, Giancarlo; Montevecchi, Franco Maria; Ferrari, Mauro

    2008-04-01

    Osmometry is an essential technique for solution analysis and the investigation of chemical and biological phenomena. Commercially available osmometers rely on the measurements of freezing point, vapor pressure, and osmotic pressure of solutions. Although vapor pressure osmometry (VPO) and freezing point osmometry (FPO) can perform rapid and inexpensive measurements, they are indirect techniques, which rely on thermodynamic assumptions, which limit their applicability. While membrane osmometry (MO) provides a potentially unlimited direct measurement of osmotic pressure and solution osmolality, the conventional technique is often time-consuming and difficult to operate. In the present work, a novel membrane osmometer is presented. The instrument significantly reduces the conventional MO measurement time and is not subject to the limitations of VPO and FPO. For this paper, the osmotic pressure of aqueous sucrose solutions was collected in a molality range 0-5.5, by way of demonstration of the new instrument. When compared with data found in the literature, the experimental data were generally in good agreement. However, differences among results from the three techniques were observed.

  7. In-pile vapor pressure measurements on UO2 and (U,Pu)O2

    International Nuclear Information System (INIS)

    Breitung, W.; Reil, K.O.

    1985-08-01

    The Effective-Equation-of-State (EEOS) experiments investigated the saturation vapor pressures of ultra pure UO 2 , reactor grade UO 2 , and reactor grade (Usub(.77)Pusub(.23))O2 using newly developed in-pile heating techniques. For enthalpies between 2150 and 3700 kJ/kg (about 4700 to 8500 K) vapor pressures from 1.3 to 54 MPa were measured. The p-h curves of all three fuel types were identical within the experimental uncertainties. An assessment of all published p-h measurements showed that the p-h saturation curve of UO 2 appears now well established by the EEOS and the CEA in-pile data. Using an estimate for the heat capacity of liquid UO 2 , the in-pile results were also compared to earlier p-T measurements. The assessments lead to proposal of two equations. Equation I, which includes a factor-of-2 uncertainty band, covers all p-T equilibrium evaporation measurements. Equation I yields 3817 K for the normal boiling point, 415.4 kJ/mol for the corresponding heat of vaporization, and 1.90 MPa for the vapor pressure at 5000 K. Equations I and II, which represent a parametric form of the p-h curve (T=parameter), also give a good description of the EEOS and CEA in-pile data. Thus the proposed equations allow a consistent representation of both p-T and p-h measurements, they are sufficiently precise for CDA analyses and cover the whole range of interest (3120-8500 K, 1400-3700 kJ/kg). (orig./HP) [de

  8. 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

  9. Improvement of the accuracy of vapor pressure measurements by quartz membrane manometers

    Science.gov (United States)

    Rusin, A. D.

    2008-06-01

    The sensitivity of and instrumental errors in high-temperature vapor pressure measurements by two quartz crescent-shaped manometers of enhanced sensitivity were determined; the thermal drift of their zero pints was studied. The contributions of instrumental errors and thermal drift to the total sample variance of pressure were found. The main source of the total error in pressure was shown to be zero point thermal drift and errors in the determination of the position of the membrane pin. Compared with the usual design of these membrane manometers, sensitivity was higher 14.7 and 21.3 times, and measurement errors were lower 5.4 and 19 times, respectively. The two manometers studied gave pressure errors of 0.13 and 0.32 torr, respectively, at a 0.95 confidence probability.

  10. GOZCARDS Source 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 Source Data for Water Vapor Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozSmlpH2O) contains zonal means and related...

  11. 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...

  12. 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....

  13. High-Pressure Solvent Vapor Annealing with a Benign Solvent To Rapidly Enhance the Performance of Organic Photovoltaics.

    Science.gov (United States)

    Jung, Buyoung; Kim, Kangmin; Eom, Yoomin; Kim, Woochul

    2015-06-24

    A high-pressure solvent vapor annealing (HPSVA) treatment is suggested as an annealing process to rapidly achieve high-performance organic photovoltaics (OPVs); this process can be compatible with roll-to-roll processing methods and uses a benign solvent: acetone. Solvent vapor annealing can produce an advantageous vertical distribution in the active layer; however, conventional solvent vapor annealing is also time-consuming. To shorten the annealing time, high-pressure solvent vapor is exposed on the active layer of OPVs. Acetone is a nonsolvent for poly(3-hexylthiophene-2,5-diyl) (P3HT), but it can dissolve small amounts of 1-(3-methoxycarbonyl)-propyl-1,1-phenyl-(6,6)C61 (PCBM). Acetone vapor molecules can penetrate into the active layer under high vapor pressure conditions to alter the morphology. HPSVA induces a PCBM-rich phase near the cathode and facilitates the transport of free charge carriers to the electrode. Although P3HT is not soluble in acetone, locally rearranged P3HT crystallites are generated. The performance of OPV films was enhanced after HPSVA; the film treated at 30 kPa for 10 s showed optimum performance. Additionally, this HPSVA method could be adapted for mass production because the temporary exposure of films to high-pressure acetone vapor in ambient conditions also improved performance.

  14. 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.

  15. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. 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

  18. Probabilistic approach: back pressure turbine for geothermal vapor-dominated system

    Science.gov (United States)

    Alfandi Ahmad, Angga; Xaverius Guwowijoyo, Fransiscus; Pratama, Heru Berian

    2017-12-01

    Geothermal bussiness nowadays needs to be accelerated in a way that profit can be obtained as soon as reasonable possible. One of the many ways to do this is by using one of geothermal wellhead generating unit (GWGU), called backpressure turbine. Backpressure turbine can be used in producing electricity as soon as there is productive or rather small-scale productive well existed after finished drilling. In a vapor dominated system, steam fraction in the wellhead capable to produce electricity based on each well productivity immediately. The advantage for using vapor dominated system is reduce brine disposal in the wellhead so it will be a cost benefit in operation. The design and calculation for backpressure turbine will use probablistic approach with Monte Carlo simulation. The parameter that will be evaluated in sensitivity would be steam flow rate, turbine inlet pressure, and turbine exhaust pressure/atmospheric pressure. The result are probability for P10, P50, and P90 of gross power output which are 1.78 MWe, 2.22 MWe and 2.66 Mwe respectively. Whereas the P10, P50, and P90 of SSC are 4.67 kg/s/MWe, 5.19 kg/s/MWe and 5.78 kg/s/MWe respectively.

  19. 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.

  20. Evaluation of Vapor Pressure Estimation Methods for Use in Simulating the Dynamic of Atmospheric Organic Aerosols

    Directory of Open Access Journals (Sweden)

    A. J. Komkoua Mbienda

    2013-01-01

    Lee and Kesler (LK, and Ambrose-Walton (AW methods for estimating vapor pressures ( are tested against experimental data for a set of volatile organic compounds (VOC. required to determine gas-particle partitioning of such organic compounds is used as a parameter for simulating the dynamic of atmospheric aerosols. Here, we use the structure-property relationships of VOC to estimate . The accuracy of each of the aforementioned methods is also assessed for each class of compounds (hydrocarbons, monofunctionalized, difunctionalized, and tri- and more functionalized volatile organic species. It is found that the best method for each VOC depends on its functionality.

  1. 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.

  2. 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.

  3. HIGH PRESSURE VAPOR-LIQUID EQUILIBRIA OF PALM FATTY ACIDS DISTILLATES-CARBON DIOXIDE SYSTEM

    Directory of Open Access Journals (Sweden)

    MACHADO Nélio T.

    1997-01-01

    Full Text Available Vapor-Liquid equilibria of palm fatty acids distillates/carbon dioxide system has been investigated experimentally at temperatures of 333, 353, and 373 K and pressures of 20, 23, 26, and 29 MPa using the static method. Experimental data for the quasi-binary system palm fatty acids distillates/carbon dioxide has been correlated with Redlich-Kwong-Aspen equation of state. Modeling shows good agreement with experimental data. Selectivity obtained indicates that supercritical carbon dioxide is a reasonable solvent for separating saturated (palmitic acid and unsaturated (oleic+linoleic acids fatty acids from palm fatty acids distillates in a continuous multistage countercurrent column.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. The vapor pressures and activities of dicarboxylic acids reconsidered: the impact of the physical state of the aerosol

    Directory of Open Access Journals (Sweden)

    V. Soonsin

    2010-12-01

    Full Text Available We present vapor pressure data of the C2 to C5 dicarboxylic acids deduced from measured evaporation rates of single levitated particles as both, aqueous droplets and solid crystals. The data of aqueous solution particles over a wide concentration range allow us to directly calculate activities of the dicarboxylic acids and comparison of these activities with parameterizations reported in the literature. The data of the pure liquid state acids, i.e. the dicarboxylic acids in their supercooled melt state, exhibit no even-odd alternation in vapor pressure, while the acids in the solid form do. This observation is consistent with the known solubilities of the acids and our measured vapor pressures of the supercooled melt. Thus, the gas/particle partitioning of the different dicarboxylic acids in the atmosphere depends strongly on the physical state of the aerosol phase, the difference being largest for the even acids. Our results show also that, in general, measurements of vapor pressures of solid dicarboxylic acids may be compromised by the presence of polymorphic forms, crystalline structures with a high defect number, and/or solvent inclusions in the solid material, yielding a higher vapor pressure than the one of the thermodynamically stable crystalline form at the same temperature.

  10. D0 Silicon Upgrade: Vapor Pressure Thermometry System Near LN2 Subcooler

    Energy Technology Data Exchange (ETDEWEB)

    Kuwazaki, Andrew; /Fermilab

    1996-07-01

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

  11. 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

  12. Assessment of vapor pressure estimation methods for secondary organic aerosol modeling

    Science.gov (United States)

    Camredon, Marie; Aumont, Bernard

    Vapor pressure ( Pvap) is a fundamental property controlling the gas-particle partitioning of organic species. Therefore this pure substance property is a critical parameter for modeling the formation of secondary organic aerosols (SOA). Structure-property relationships are needed to estimate Pvap because (i) very few experimental data for Pvap are available for semi-volatile organics and (ii) the number of contributors to SOA is extremely large. The Lee and Kesler method, a modified form of the Mackay equation, the Myrdal and Yalkowsky method and the UNIFAC- pLo method are commonly used to estimate Pvap in gas-particle partitioning models. The objectives of this study are (i) to assess the accuracy of these four methods on a large experimental database selected to be representative of SOA contributors and (ii) to compare the estimates provided by the various methods for compounds detected in the aerosol phase.

  13. Effect of additives on the antiknock properties and Reid vapor pressure of gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Rosangela da Silva; Renato Cataluna; Eliana Weber de. Menezes; Dimitrios Samios; Clarisse M. Sartori Piatnicki [Federal University of Rio Grande do Sul, Porto Alegre (Brazil). Department of Physical Chemistry, Institute of Chemistry

    2005-05-01

    An evaluation was made of the effect produced by the addition of oxygenates such as ethanol, ETBE and MTBE and nonoxygenates such as isooctane and toluene on the Reid vapor pressure (RVP) and octane number of two types of gasoline with different chemical compositions. Locally produced gasoline was blended with five different percentages (v/v) of the additives, i.e. 5, 10, 15, 20 and 25%. Ethanol and MTBE increased significantly the RVP of the mixtures, but ETBE, and particularly toluene and isooctane, decreased the RVP of the original fractions when mixed with gasoline. The octane rating of gasoline was found to increase continuously and linearly with the addition of the oxygenated compounds toluene and isooctane. Moreover, the mixture octane number of the oxygenated compounds was superior to the octane number of the same compounds of high purity grade. 37 refs., 4 figs., 5 tabs.

  14. 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.

  15. 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.

  16. Numerical simulation of fragmentation of melt drop triggered by external pressure pulse in vapor explosions

    International Nuclear Information System (INIS)

    Zhou, Yuan; Zhang, Zhengming; Lin, Meng; Minghao, Yuan; Xiao, Yan

    2013-01-01

    Highlights: ► A multi-phase thermal hydraulic code with volume of fluid method is developed. ► The molten metal drop fragmentation process is simulated to investigate the responsible mechanisms. ► The growth and breakup of filaments around the drop are numerically analyzed. ► High pressure spots which induce filament growth are observed in simulation results. ► Water jet penetration assumed in Kim’s model (Nucl. Sci. Eng., 98, 16–28, 1988) is not observed in the simulation results. - Abstract: The fragmentation of molten drops is the key process in the fuel–coolant interaction (FCIs) which may occur during the course of a severe accident in a light water reactor (LWR). However, the mechanisms of this complicated process cannot be clarified sufficiently by experimental studies due to the rapid reaction. In this paper, a multi-phase thermal hydraulic code with the volume of fluid method (VOF) is developed and the fragmentation process of melt drops triggered by external pressure pulse is numerically analyzed to investigate the mechanism of fragmentation in vapor explosions. The simulation results show that the fragmentation process can be divided into several stages, including vapor film collapse, melt drop-coolant direct contact, formation of high pressure spots, rapid growth of a filament around the molten metal drop, rapid fuel coolant interaction area expansion, breaking up of the filament, and mixing of fragments with water. The calculation results are similar to Ciccarelli and Frost’s (Nucl. Eng. Des., 146, 109–132) experiment data. The simulation results suggest that growth and breaking up of a filament are the essential mechanism of melt tin drop fragmentation. Penetration and evaporation of the water jets, which are assumed as fragmentation mechanism in Kim’s model (Nucl. Sci. Eng., 98, 16–28, 1988), are not observed. In the calculation case, when molten metal density is hypothetically smaller, the water penetration is observed

  17. 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

  18. 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.

  19. Thermodynamics of the multicomponent vapor-liquid equilibrium under capillary pressure difference

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2001-01-01

    algorithms of flash calculations in order to solve these problems. Sample calculations show large variation of the capillary properties of the mixture in the very neighborhood of the phase envelope and the restrictive role of the spinodal surface as a boundary for possible equilibrium states with different...... pressures. (C) 2001 Elsevier Science B.V. All rights reserved....

  20. 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.

  1. 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.

  2. [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.

  3. Determination of vapor-liquid equilibrium data in microfluidic segmented flows at elevated pressures using Raman spectroscopy.

    Science.gov (United States)

    Luther, Sebastian K; Stehle, Simon; Weihs, Kristian; Will, Stefan; Braeuer, Andreas

    2015-08-18

    A fast, noninvasive, and efficient analytical measurement strategy for the characterization of vapor-liquid equilibria (VLE) is presented, which is based on phase (state of matter) selective Raman spectroscopy in multiphase flows inside microcapillay systems (MCS). Isothermal VLE data were measured in binary and ternary mixtures composed of acetone, water, carbon dioxide or nitrogen at elevated pressures up to 10 MPa and temperatures up to 333 K. For validation, the obtained data were compared with literature data and reference measurements in a high-pressure variable volume cell. Additionally, the mixtures were investigated at temperatures and pressures where no data is available in literature to extend the high-pressure VLE database.

  4. 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…

  5. 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...

  6. Development of a method for measuring the ortho-positronium quenching rate in low vapor-pressure gases

    International Nuclear Information System (INIS)

    Wada, K.; Saito, F.; Hyodo, T.

    2009-01-01

    A new measurement and analysis method for determining the ortho-positronium collisional quenching rate for low vapor-pressure gases is developed. It uses hydrophobic silica aerogels as highly efficient positronium formation media and microchambers. The value of the normalized positronium quenching rate, 1 Z eff , for CH 3 Br measured by this method is 0.70 ± 0.04.

  7. 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

  8. 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.

  9. Electron transport in mercury vapor: cross sections, pressure and temperature dependence of transport coefficients and NDC effects★

    Science.gov (United States)

    Mirić, Jasmina; Simonović, Ilija; Petrović, Zoran Lj.; White, Ronald D.; Dujko, Saša

    2017-11-01

    In this work we propose a complete and consistent set of cross sections for electron scattering in mercury vapor. The set is validated through a series of comparisons between swarm data calculated using a multi term theory for solving the Boltzmann equation and Monte Carlo simulations, and the available experimental data. Other sets of cross sections for electron scattering in mercury vapor were also used as input in our numerical codes with the aim of testing their completeness, consistency and accuracy. The calculated swarm parameters are compared with measurements in order to assess the quality of the cross sections in providing data for plasma modeling. In particular, we discuss the dependence of transport coefficients on the pressure and temperature of mercury vapor, and the occurrence of negative differential conductivity (NDC) in the limit of lower values of E/N. We have shown that the phenomenon of NDC is induced by the presence of mercury dimers and that can be controlled by varying either pressure or temperature of mercury vapor. The effective inelastic cross section for mercury dimers is estimated for a range of pressures and temperatures. It is shown that the measured and calculated drift velocities agree very well only if the effective inelastic cross section for mercury dimers and thermal motion of mercury atoms are carefully considered and implemented in numerical calculations. Contribution to the Topical Issue "Physics of Ionized Gases (SPIG 2016)", edited by Goran Poparic, Bratislav Obradovic, Dragana Maric and Aleksandar Milosavljevic.

  10. 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

  11. Exchange of Na+ and K+ between water vapor and feldspar phases at high temperature and low vapor pressure

    Science.gov (United States)

    Fournier, R.O.

    1976-01-01

    In order to determine whether gas (steam) containing a small amount of dissolved alkali chloride is effective in promoting base exchange of Na+ and K+ among alkali feldspars and coexisting brine or brine plus solid salt, experiments were carried out at 400-700??C and steam densities ranging down to less than 0.05. For bulk compositions rich in potassium, the low pressure results are close to previous high-pressure results in composition of the fluid and coexisting solid phase. However, when the bulk composition is more sodic, alkali feldspars are relatively richer in potassium at low pressure than at high pressure. This behaviour corresponds to enrichment of potassium in the gas phase relative to coexisting brine and precipitation of solid NaCl when the brine plus gas composition becomes moderately sodic. The gas phase is very effective in promoting base exchange between coexisting alkali feldspars at high temperature and low water pressure. This suggests that those igneous rocks which contain coexisting alkali feldspars out of chemical equilibrium either remained very dry during the high-temperature part of their cooling history or that the pore fluid was a gas containing very little potassium relative to sodium. ?? 1976.

  12. 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

  13. On the interpretation of vapor pressure measurements on oxide fuel at very-high temperatures for fast reactor safety analysis

    International Nuclear Information System (INIS)

    Bober, M.; Breitung, W.; Karow, H.U.; Schretzmann, K.

    1976-01-01

    Safety analysis of fast reactors requires knowledge of the evaporation behavior and the total vapor pressure of oxide fuel materials in the temperature region from 3000 K upwards. Dynamic vapor pressure measurements on liquid oxide fuels performed in open-evaporation experiments with laser heating techniques imply strong alterations in the composition of the incongruently evaporating fuel surface, since, during evaporation, the depletion in the preferentially evaporating components cannot be resupplied by diffusion from the bulk material. After a short transient evaporation period stationary surface-evaporation is reached with a surface composition which differs greatly from the given fuel composition and depends on the actual evaporation temperature. When this stationary forced-congruent evaporation mode is reached, the gross vapor composition is well-defined and is identical to the bulk composition of the fuel but is quite different from the actual surface composition. In consequence, the total vapor pressure developing in open surface-evaporation of a liquid oxide fuel can substantially deviate from its thermodynamic equation-of-state, in the case of (Usub(0.80)Pusub(0.20)) mixed oxide by a factor of 2 to 7 depending on the O/M-ratio. Following these thermodynamic calculations direct measurement of the equation-of-state in open-evaporation experiments is practically impossible. Theoretically fitted expressions applicable in reactor safety analysis are presented for the equations-of-state and the vapor pressure equations for open surface-evaporation and also for the heats of evaporation of liquid (Usub(0.80)Pusub(0.20)) 0sub(1.95...2.00) mixed oxides. (Auth.)

  14. 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.

  15. Vapor pressure deficit predicts epiphyte abundance across an elevational gradient in a tropical montane region.

    Science.gov (United States)

    Gotsch, Sybil G; Davidson, Kenneth; Murray, Jessica G; Duarte, Vanessa J; Draguljić, Danel

    2017-12-01

    Tropical Montane Cloud Forests (TMCFs) are important ecosystems to study and preserve because of their high biodiversity and critical roles in local and regional ecosystem processes. TMCFs may be particularly affected by changes in climate because of the narrow bands of microclimate they occupy and the vulnerability of TMCF species to projected increases in cloud base heights and drought. A comprehensive understanding of the structure and function of TMCFs is lacking and difficult to attain because of variation in topography within and across TMCF sites. This causes large differences in microclimate and forest structure at both large and small scales. In this study, we estimated the abundance of the entire epiphyte community in the canopy (bryophytes, herbaceous vascular plants, woody epiphytes, and canopy dead organic matter) in six sites. In each of the sites we installed a complete canopy weather station to link epiphyte abundance to a number of microclimatic parameters. We found significant differences in epiphyte abundance across the sites; epiphyte abundance increased with elevation and leaf wetness, but decreased as vapor pressure deficit (VPD) increased. Epiphyte abundance had the strongest relationship with VPD; there were differences in VPD that could not be explained by elevation alone. By measuring this proxy of canopy VPD, TMCF researchers will better understand differences in microclimate and plant community composition across TMCF sites. Incorporating such information in comparative studies will allow for more meaningful comparisons across TMCFs and will further conservation and management efforts in this ecosystem. © 2017 Botanical Society of America.

  16. The Evolution of Mechanisms Driving the Stomatal Response to Vapor Pressure Deficit1[OPEN

    Science.gov (United States)

    McAdam, Scott A.M.; Brodribb, Timothy J.

    2015-01-01

    Stomatal responses to vapor pressure deficit (VPD) are a principal means by which vascular land plants regulate daytime transpiration. While much work has focused on characterizing and modeling this response, there remains no consensus as to the mechanism that drives it. Explanations range from passive regulation by leaf hydration to biochemical regulation by the phytohormone abscisic acid (ABA). We monitored ABA levels, leaf gas exchange, and water status in a diversity of vascular land plants exposed to a symmetrical, mild transition in VPD. The stomata in basal lineages of vascular plants, including gymnosperms, appeared to respond passively to changes in leaf water status induced by VPD perturbation, with minimal changes in foliar ABA levels and no hysteresis in stomatal action. In contrast, foliar ABA appeared to drive the stomatal response to VPD in our angiosperm samples. Increased foliar ABA level at high VPD in angiosperm species resulted in hysteresis in the recovery of stomatal conductance; this was most pronounced in herbaceous species. Increased levels of ABA in the leaf epidermis were found to originate from sites of synthesis in other parts of the leaf rather than from the guard cells themselves. The transition from a passive regulation to ABA regulation of the stomatal response to VPD in the earliest angiosperms is likely to have had critical implications for the ecological success of this lineage. PMID:25637454

  17. Effects of hot isostatic pressure on titanium nitride films deposited by physical vapor deposition

    Directory of Open Access Journals (Sweden)

    Carbonari M.J.

    2001-01-01

    Full Text Available Films of titanium nitride deposited by physical vapor deposition on 304 L stainless steel substrates were hot isostatic pressed (HIP under 150 MPa at 550 °C. To study the effects of this treatment on the microstructure of those films, X-ray diffraction analyses, Rutherford Backscattering spectroscopy, scanning electron microscopy, and atomic force microscopy were performed. Surface hardness, and roughness were also evaluated to characterize the TiN properties. The hot isostatic pressure leads to an increase of hardness for depths up to 0.1 mum and a crystallographic texture change from (111 to (200. The original TiN golden color turned to red after the treatment. An increase of the grain size has been observed for hot isostatic pressed samples, but the stoichiometry of the TiN film was determined to be 1:1 by RBS. The microstructure observed by atomic force microscopy indicated that the TiN film surface is smoother after the HIP treatment.

  18. Vapor-pressure deficit and extreme climatic variables limit tree growth.

    Science.gov (United States)

    Sanginés de Cárcer, Paula; Vitasse, Yann; Peñuelas, Josep; Jassey, Vincent E J; Buttler, Alexandre; Signarbieux, Constant

    2018-03-01

    Assessing the effect of global warming on forest growth requires a better understanding of species-specific responses to climate change conditions. Norway spruce and European beech are among the dominant tree species in Europe and are largely used by the timber industry. Their sensitivity to changes in climate and extreme climatic events, however, endangers their future sustainability. Identifying the key climatic factors limiting their growth and survival is therefore crucial for assessing the responses of these two species to ongoing climate change. We studied the vulnerability of beech and spruce to warmer and drier conditions by transplanting saplings from the top to the bottom of an elevational gradient in the Jura Mountains in Switzerland. We (1) demonstrated that a longer growing season due to warming could not fully account for the positive growth responses, and the positive effect on sapling productivity was species-dependent, (2) demonstrated that the contrasting growth responses of beech and spruce were mainly due to different sensitivities to elevated vapor-pressure deficits (VPD), (3) determined the species-specific limits to VPD above which growth rate began to decline, and (4) demonstrated that models incorporating extreme climatic events could account for the response of growth to warming better than models using only average values. These results support that the sustainability of forest trees in the coming decades will depend on how extreme climatic events will change, irrespective of the overall warming trend. © 2017 John Wiley & Sons Ltd.

  19. Atmospheric Pressure Spray Chemical Vapor Deposited CuInS2 Thin Films for Photovoltaic Applications

    Science.gov (United States)

    Harris, J. D.; Raffaelle, R. P.; Banger, K. K.; Smith, M. A.; Scheiman, D. A.; Hepp, A. F.

    2002-01-01

    Solar cells have been prepared using atmospheric pressure spray chemical vapor deposited CuInS2 absorbers. The CuInS2 films were deposited at 390 C using the single source precursor (PPh3)2CuIn(SEt)4 in an argon atmosphere. The absorber ranges in thickness from 0.75 - 1.0 micrometers, and exhibits a crystallographic gradient, with the leading edge having a (220) preferred orientation and the trailing edge having a (112) orientation. Schottky diodes prepared by thermal evaporation of aluminum contacts on to the CuInS2 yielded diodes for films that were annealed at 600 C. Solar cells were prepared using annealed films and had the (top down) composition of Al/ZnO/CdS/CuInS2/Mo/Glass. The Jsc, Voc, FF and (eta) were 6.46 mA per square centimeter, 307 mV, 24% and 0.35%, respectively for the best small area cells under simulated AM0 illumination.

  20. Threefold atmospheric-pressure annealing for suppressing graphene nucleation on copper in chemical vapor deposition

    Science.gov (United States)

    Suzuki, Seiya; Nagamori, Takashi; Matsuoka, Yuki; Yoshimura, Masamichi

    2014-09-01

    Chemical vapor deposition (CVD) is a promising method of producing a large single-crystal graphene on a catalyst, especially on copper (Cu), and a further increase in domain size is desirable for electro/optic applications. Here, we report on threefold atmospheric-pressure (ATM) annealing for suppressing graphene nucleation in atmospheric CVD. Threefold ATM annealing formed a step and terrace surface of the underlying Cu, in contrast to ATM annealing. Atomic force microscopy and Auger electron mapping revealed that Si-containing particles existed on threefold-ATM- and ATM-annealed surfaces; particles on Cu had a lower density after threefold ATM annealing than after ATM annealing. The formation of a step and terrace surface and the lower density of particles following the threefold ATM annealing would play a role in reducing graphene nucleation. By combining threefold ATM annealing and electropolishing of Cu, the nucleation of graphene was effectively suppressed, and a submillimeter-sized hexagonal single-crystal graphene was successfully obtained.

  1. Low-Pressure Vapor-Assisted Solution Process for Thiocyanate-Based Pseudohalide Perovskite Solar Cells.

    Science.gov (United States)

    Chiang, Yu-Hsien; Cheng, Hsin-Min; Li, Ming-Hsien; Guo, Tzung-Fang; Chen, Peter

    2016-09-22

    In this report, we fabricated thiocyanate-based perovskite solar cells with low-pressure vapor-assisted solution process (LP-VASP) method. Photovoltaic performances are evaluated with detailed materials characterizations. Scanning electron microscopy images show that SCN-based perovskite films fabricated using LP-VASP have long-range uniform morphology and large grain sizes up to 1 μm. The XRD and Raman spectra were employed to observe the characteristic peaks for both SCN-based and pure CH 3 NH 3 PbI 3 perovskite. We observed that the Pb(SCN) 2 film transformed to PbI 2 before the formation of perovskite film. X-ray photoemission spectra (XPS) show that only a small amount of S remained in the film. Using LP-VASP method, we fabricated SCN-based perovskite solar cells and achieved a power conversion efficiency of 12.72 %. It is worth noting that the price of Pb(SCN) 2 is only 4 % of PbI 2 . These results demonstrate that pseudo-halide perovskites are promising materials for fabricating low-cost perovskite solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The Relative Importance of Aqueous vs. Vapor-Pressure Dependent Pathways for Particulate Organic Nitrate Formation

    Science.gov (United States)

    Zare, A.; Pye, H. O. T.; Cohen, R. C.

    2016-12-01

    Formation of biogenic derived organic nitrates is known as an important immediate sink of atmospheric nitrogen oxides. Although, subsequent oxidation and photolysis of organic nitrates can return a part of the sequestered NOx to the atmosphere, other removal pathways in combination with wet and dry deposition and hydrolysis of particulate organic nitrates is of central importance in irreversible NOx removal from the atmosphere. The aim of this work is to understand how and to what degree the particle phase participates in removal of NOx. We implement a new BVOC oxidation gas phase mechanism (including a detailed representation of OH- and NO3-initiated organic nitrates) and an explicit representation of organic nitrate aerosols formation, including irreversible aqueous-phase uptake and reversible partitioning onto pre-existing organic aerosol, into the CMAQ model. Using these mechanisms, we simulate observations from the SOAS field campaigns over the southeast US in summer 2013 and examine the relative role of water-mediated vs vapor pressure processes in determining aerosol from organic nitrates.

  3. Prediction of aqueous solubility, vapor pressure and critical micelle concentration for aquatic partitioning of perfluorinated chemicals.

    Science.gov (United States)

    Bhhatarai, Barun; Gramatica, Paola

    2011-10-01

    The majority of perfluorinated chemicals (PFCs) are of increasing risk to biota and environment due to their physicochemical stability, wide transport in the environment and difficulty in biodegradation. It is necessary to identify and prioritize these harmful PFCs and to characterize their physicochemical properties that govern the solubility, distribution and fate of these chemicals in an aquatic ecosystem. Therefore, available experimental data (10-35 compounds) of three important properties: aqueous solubility (AqS), vapor pressure (VP) and critical micelle concentration (CMC) on per- and polyfluorinated compounds were collected for quantitative structure-property relationship (QSPR) modeling. Simple and robust models based on theoretical molecular descriptors were developed and externally validated for predictivity. Model predictions on selected PFCs were compared with available experimental data and other published in silico predictions. The structural applicability domains (AD) of the models were verified on a bigger data set of 221 compounds. The predicted properties of the chemicals that are within the AD, are reliable, and they help to reduce the wide data gap that exists. Moreover, the predictions of AqS, VP, and CMC of most common PFCs were evaluated to understand the aquatic partitioning and to derive a relation with the available experimental data of bioconcentration factor (BCF).

  4. [Determination and prediction for vapor pressures of organophosphate flame retardants by gas chromatography].

    Science.gov (United States)

    Wang, Qingzhi; Zhao, Hongxia; Wang, Yan; Xie, Qing; Chen, Jingwen; Quan, Xie

    2017-09-08

    Organophosphate flame retardants (OPFRs) are ubiquitous in the environment. To better understand and predict their environmental transport and fate, well-defined physicochemical properties are required. Vapor pressures ( P ) of 14 OPFRs were estimated as a function of temperature ( T ) by gas chromatography (GC), while 1,1,1-trichioro-2,2-bis (4-chlorophenyl) ethane ( p,p '-DDT) was acted as a reference substance. Their log P GC values and internal energies of phase transfer (△ vap H ) ranged from -6.17 to -1.25 and 74.1 kJ/mol to 122 kJ/mol, respectively. Substitution pattern and molar volume ( V M ) were found to be capable of influencing log P GC values of the OPFRs. The halogenated alkyl-OPFRs had lower log P GC values than aryl-or alkyl-OPFRs. The bigger the molar volume was, the smaller the log P GC value was. In addition, a quantitative structure-property relationship (QSPR) model of log P GC versus different relative retention times (RRTs) was developed with a high cross-validated value ( Q 2 cum ) of 0.946, indicating a good predictive ability and stability. Therefore, the log P GC values of the OPFRs without standard substance can be predicted by using their RRTs on different GC columns.

  5. Uniformly Distributed Graphene Domain Grows on Standing Copper via Low-Pressure Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Shih-Hao Chan

    2013-01-01

    Full Text Available Uniformly distributed graphene domains were synthesized on standing copper foil by a low-pressure chemical vapor deposition system. This method improved the distribution of the graphene domains at different positions on the same piece of copper foil along the forward direction of the gas flow. Scanning electron microscopy (SEM showed the average size of the graphene domains to be about ~20 m. This results show that the sheet resistance of monolayer graphene on a polyethylene terephthalate (PET substrate is about ~359 /□ whereas that of the four-layer graphene films is about ~178 /□, with a transmittance value of 88.86% at the 550 nm wavelength. Furthermore, the sheet resistance can be reduced with the addition of HNO3 resulting in a value of 84 /□. These values meet the absolute standard for touch sensor applications, so we believe that this method can be a candidate for some transparent conductive electrode applications.

  6. The correlation between pulsatile intracranial pressure and indices of intracranial pressure-volume reserve capacity: results from ventricular infusion testing.

    Science.gov (United States)

    Eide, Per Kristian

    2016-12-01

    OBJECTIVE The objective of this study was to examine how pulsatile and static intracranial pressure (ICP) scores correlate with indices of intracranial pressure-volume reserve capacity, i.e., intracranial elastance (ICE) and intracranial compliance (ICC), as determined during ventricular infusion testing. METHODS All patients undergoing ventricular infusion testing and overnight ICP monitoring during the 6-year period from 2007 to 2012 were included in the study. Clinical data were retrieved from a quality registry, and the ventricular infusion pressure data and ICP scores were retrieved from a pressure database. The ICE and ICC (= 1/ICE) were computed during the infusion phase of the infusion test. RESULTS During the period from 2007 to 2012, 82 patients with possible treatment-dependent hydrocephalus underwent ventricular infusion testing within the department of neurosurgery. The infusion tests revealed a highly significant positive correlation between ICE and the pulsatile ICP scores mean wave amplitude (MWA) and rise-time coefficient (RTC), and the static ICP score mean ICP. The ICE was negatively associated with linear measures of ventricular size. The overnight ICP recordings revealed significantly increased MWA (> 4 mm Hg) and RTC (> 20 mm Hg/sec) values in patients with impaired ICC ( 4 mm Hg, RTC > 20 mm Hg/sec), but not increased mean ICP (pressure-volume reserve capacity, i.e., ICE and ICC.

  7. 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

    ... for gases and vapors; Type C supplied-air respirators, demand and pressure-demand classes; test... ......do ......do The air-supply hose, detachable coupling, and demand valve of the demand class or pressure-demand valve of the pressure-demand class for Type C supplied-air respirators, demand and pressure...

  8. Synthesis of ZnO nanocrystals with novel hierarchical structures via atmosphere pressure physical vapor deposition method

    Science.gov (United States)

    Yan, Youguo; Zhang, Ye; Meng, Guowen; Zhang, Lide

    2006-09-01

    The search for hierarchically organized ZnO nanocrystals have been intense in recent years, due to both fundamental interest in nanocrystal growth subjects and their potential applications as components for building nanodetectors, optoelectronic, vacuum microelectronic, and spintronic nanodevices. We reported the first observation of a variety of novel nanostructures, such as nanocandle arrays, wine-bottle-shaped rod arrays, nanorivet arrays, periodic diamond-string and needle arrays, nanofern and needle arrays, tooth-shaped belt, spinal-shaped nanostructures and bamboo-shaped nanorod via an atmosphere pressure physical vapor deposition method. The unique feature of our method is atmosphere chamber pressure, which can induce chaos and fluctuation of source vapor and facilities multiply growth mechanisms to have competing dominating effects on the crystal growth of ZnO. The SEM and photoluminescence spectra confirm that those nanostructured ZnO crystals possess satisfactory structural and optical qualities.

  9. 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

  10. Oxidizer partial pressure window for YBa2Cu3O(7-x) thin film formation by metalorganic chemical vapor deposition

    Science.gov (United States)

    Chern, C. S.; Zhao, J.; Norris, P. E.; Garrison, S. M.; Yau, K.; Li, Y. Q.; Gallois, B. M.; Kear, B. H.

    1992-10-01

    We conducted a systematic study of oxidizer partial pressure effects on both the superconducting transport properties and structural properties of YBa2Cu3O(7-x) (YBCO) films grown by conventional metalorganic chemical vapor deposition (MOCVD). Superconducting YBCO thin films were grown in partial N2O pressures ranging from 0.4 to 45 Torr and at substrate temperatures of 500 and 700 C. We observed a window in oxidizer partial pressure within which YBCO thin films can be formed in the as-deposited state by the MOCVD process. A trend of increasing b-axis orientation as the oxidizer partial pressure increased was revealed by detailed X-ray diffraction. The reduction of superconducting properties for films grown at high oxidizer partial pressure might result from the lack of surface mobility.

  11. Human Pressures on Natural Reserves in Yunnan Province and Management Implications.

    Science.gov (United States)

    Qiu, Cheng; Hu, Jinming; Yang, Feiling; Liu, Feng; Li, Xinwang

    2018-02-19

    The analysis of status and major sources of human pressures on natural reserves (NRs) is important for optimizing their management. This study selected population density, gross domestic product (GDP) density and areal percentage of human land use to reveal the human pressures of national and provincial NRs (NNRs and PNRs) in Yunnan Province, China. We calculated three types of internal and external human pressure index (HPI) and comprehensive HPI (CHPI) for NRs. Human pressures on most of NRs were slight and light, indicating that most of NRs were well protected. Human pressures on PNRs were higher than on NNRs; with respect to five types of NRs, geological relict NRs were facing the highest human pressures, followed by wetland ecosystem NRs. Land use and population density were the main human pressures on these NRs. Yunnan Province should put the highest emphasis on three NNRs and two Ramsar site PNRs with severe CHPI, secondly pay attention to eight conservation-oriented PNRs with extreme or severe CHPI. It's urgent for Yunnan to implement scientific policies and measures to reduce land use and population density pressures of NRs, especially with severe and extreme CHPI, by transforming internal land use and/or implementing residents' eco-migration.

  12. Relationship between heating atmosphere and copper foil impurities during graphene growth via low pressure chemical vapor deposition

    OpenAIRE

    Çelik, Yasemin; Escoffier, Walter; Yang, Ming; Flahaut, Emmanuel; Suvacı, Ender

    2016-01-01

    International audience; Low-pressure chemical vapor deposition synthesis of graphene films on two different Cu foils, with different surface oxygen and carbon contents, was performed by controlling H2 and/or Ar flow rates during heating. The influences of heating atmosphere on the final impurity level, quality of the synthesized graphene films and thickness uniformity were investigated depending on Cu foil impurities. Heating of carbon-rich, but oxygen-poor Cu foil in H2 environment resulted ...

  13. 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.

  14. Low temperature atmospheric pressure chemical vapor deposition of group 14 oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.M. [Houston Univ., TX (United States); Atagi, L.M. [Houston Univ., TX (United States)]|[Los Alamos National Lab., NM (United States); Chu, Wei-Kan; Liu, Jia-Rui; Zheng, Zongshuang [Houston Univ., TX (United States); Rubiano, R.R. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Springer, R.W.; Smith, D.C. [Los Alamos National Lab., NM (United States)

    1994-06-01

    Depositions of high quality SiO{sub 2} and SnO{sub 2} films from the reaction of homoleptic amido precursors M(NMe{sub 2})4 (M = Si,Sn) and oxygen were carried out in an atmospheric pressure chemical vapor deposition r. The films were deposited on silicon, glass and quartz substrates at temperatures of 250 to 450C. The silicon dioxide films are stoichiometric (O/Si = 2.0) with less than 0.2 atom % C and 0.3 atom % N and have hydrogen contents of 9 {plus_minus} 5 atom %. They are deposited with growth rates from 380 to 900 {angstrom}/min. The refractive indexes of the SiO{sub 2} films are 1.46, and infrared spectra show a possible Si-OH peak at 950 cm{sup {minus}1}. X-Ray diffraction studies reveal that the SiO{sub 2} film deposited at 350C is amorphous. The tin oxide films are stoichiometric (O/Sn = 2.0) and contain less than 0.8 atom % carbon, and 0.3 atom % N. No hydrogen was detected by elastic recoil spectroscopy. The band gap for the SnO{sub 2} films, as estimated from transmission spectra, is 3.9 eV. The resistivities of the tin oxide films are in the range 10{sup {minus}2} to 10{sup {minus}3} {Omega}cm and do not vary significantly with deposition temperature. The tin oxide film deposited at 350C is cassitterite with some (101) orientation.

  15. Vapor Pressure Deficit and Sap Velocity Dynamic Coupling in Canopy Dominant Trees in the Amazon basin

    Science.gov (United States)

    Chambers, J. Q.; Gimenez, B.; Jardine, K.; Negron Juarez, R. I.; Cobello, L. O.; Fontes, C.; Dawson, T. E.; Higuchi, N.

    2017-12-01

    In order to improve our ability to predict terrestrial water fluxes, an understanding of the interactions between plant physiology and environmental conditions is necessary, especially in tropical forests which recycle large fluxes of water to the atmosphere. This need has become more relevant due to observed records in global temperature. In this study we show a strong temporal correlation between sap velocity and leaf-to-air vapor pressure deficit (VPD) in canopy dominant trees in two primary rainforest sites in the Amazon basin (Santarém and Manaus, Brazil). As VPDs in the upper canopy (20-30 m) varied throughout the day and night, basal sap velocity (1.5 m) responded rapidly without an observable delay (< 15 min). Sap velocity showed a sigmoidal dependence on VPDs including an exponential increase, an inflection point, and a plateau, in all observed trees. Moreover, a clear diurnal hysteresis in sap velocity, stomatal conductance, and leaf water potential was evident with morning periods showing higher sensitivities to VPD than afternoon and night periods. Diurnal leaf gas exchange observations revealed a morning to midday peak in stomatal conductance, but midday to afternoon peak in transpiration and VPD. Thus, our study confirms that the temporal lag between the Gs peak and VPD peak are the major regulators of the hysteresis phenomenon as previously described by other studies. Moreover, out study provide direct evidence for the role of decreased stomatal conductance in the warm afternoon periods to reduce transpiration and allow for the partial recovery of leaf water potential to less negative values. Our results suggests the possibility of predicting evapotranspiration fluxes from ecosystem to regional scales using remote sensing of vegetation temperature from, for example, thermal images of satellites and drones.

  16. Strong influence of vapor pressure deficit on plants' water-use efficiency: a modelling approach

    Science.gov (United States)

    Yi, K.; Zhang, Q.; Novick, K. A.

    2017-12-01

    The plant's trade-off between carbon uptake and water loss, which is often represented as intrinsic water-use efficiency (iWUE), is an important determinant of how plants will respond to expected changes in climate. Here, we present on work that assesses how the response of iWUE to the climatic drivers differs across the isohydricity spectrum, and to evaluate the relative influence of climatic drivers (vapor pressure deficit (D), soil moisture (θ), and atmospheric CO2 (ca)) on iWUE. The results suggested noticeable difference in the response of iWUE to climatic drivers among the species. The iWUE of the isohydric species, which tends to regulate stomata more actively, was more responsive to the variation of θ and D compared to the anisohydric species, of which stomata regulation is less active. Among the climatic drivers, D was the most influential driver on iWUE for all species. These results are consistent with those from a complementary effort to leverage long-term eddy covariance flux records from the FLUXNET 2015 database to compare the influence of D and θ on iWUE across a wide range of biomes; this analysis revealed that D is a more influential driver of iWUE than θ in the most cases. These findings highlight the importance of atmospheric dryness on trees' physiological response, which is important to understand given the large, global increases in D expected in coming decades. As a final step, we will report on early results to evaluate performance of widely-used ecosystem models in capturing the response of iWUE to climatic drivers across regions and to find out if the projection agrees well with flux tower observations. We also attempt to seek whether the relationship between iWUE and climatic drivers can be generalized for each vegetation type or climate regime.

  17. 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)

  18. On-line coating of glass with tin oxide by atmospheric pressure chemical vapor deposition.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D.; Sopko, J.F. (PPF Industries, Pittsburgh, PA); Houf, William G.; Chae, Yong Kee; McDaniel, Anthony H.; Li, M. (PPF Industries, Pittsburgh, PA); McCamy, J.W. (PPF Industries, Pittsburgh, PA)

    2006-11-01

    Atmospheric pressure chemical vapor deposition (APCVD) of tin oxide is a very important manufacturing technique used in the production of low-emissivity glass. It is also the primary method used to provide wear-resistant coatings on glass containers. The complexity of these systems, which involve chemical reactions in both the gas phase and on the deposition surface, as well as complex fluid dynamics, makes process optimization and design of new coating reactors a very difficult task. In 2001 the U.S. Dept. of Energy Industrial Technologies Program Glass Industry of the Future Team funded a project to address the need for more accurate data concerning the tin oxide APCVD process. This report presents a case study of on-line APCVD using organometallic precursors, which are the primary reactants used in industrial coating processes. Research staff at Sandia National Laboratories in Livermore, CA, and the PPG Industries Glass Technology Center in Pittsburgh, PA collaborated to produce this work. In this report, we describe a detailed investigation of the factors controlling the growth of tin oxide films. The report begins with a discussion of the basic elements of the deposition chemistry, including gas-phase thermochemistry of tin species and mechanisms of chemical reactions involved in the decomposition of tin precursors. These results provide the basis for experimental investigations in which tin oxide growth rates were measured as a function of all major process variables. The experiments focused on growth from monobutyltintrichloride (MBTC) since this is one of the two primary precursors used industrially. There are almost no reliable growth-rate data available for this precursor. Robust models describing the growth rate as a function of these variables are derived from modeling of these data. Finally, the results are used to conduct computational fluid dynamic simulations of both pilot- and full-scale coating reactors. As a result, general conclusions are

  19. 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

  20. Densities and vapor pressures of mixed-solvent desiccant systems containing {l_brace}glycol (diethylene, or triethylene, or tetraethylene glycol) + salt (magnesium chloride) + water{r_brace}

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shangyi [R and D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Soriano, Allan N. [R and D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Manila 1002 (Philippines); Li Menghui, E-mail: mhli@cycu.edu.t [R and D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

    2010-09-15

    In this present work, new experimental data for density and vapor pressure of the mixed-solvent desiccant systems containing {l_brace}(40.0 wt%) glycol + salt + water{r_brace} were reported for temperatures up to 343.15 K at normal atmospheric condition. The considered glycols were diethylene, triethylene, and tetraethylene glycol; and the salt is magnesium chloride (wt% = 4.0, 9.0, and 16.0). The density and vapor pressure were presented as functions of temperature and compositions. An empirical equation was used to correlate the temperature and compositional dependence of the present density data and a model based on the mean spherical approximation for aqueous electrolyte solutions incorporating the pseudo-solvent approach was used to represent the measured vapor pressure as functions of temperature and composition. Satisfactory results were obtained for both density and vapor pressure calculations.

  1. Determination of octanol-air partition coefficients and supercooled liquid vapor pressures of organochlorine pesticides.

    Science.gov (United States)

    Zhang, Na; Yang, Yu; Liu, Yu; Tao, Shu

    2009-09-01

    Octanol-air partition coefficients (K(OA)) and supercooled liquid vapor pressures (P(L)) of nine organochlorine pesticides (OCPs) including p,p'-DDE, p,p'-DDD, o,p'-DDT, o,p'-DDE, o,p'-DDD, alpha-HCH, beta-HCH, gamma-HCH, delta-HCH were determined as functions of temperature using a gas chromatographic retention time method. Among them, the K(OA) of o,p'-DDE and o,p'-DDD and the P(L) of o,p'-DDE, o,p'-DDD, beta-HCH and delta-HCH were determined for the first time. The determined K(OA) and P(L) values of investigated compounds at 25 degrees C ranged from 3.14 x 10(7) (alpha-HCH) to 3.76 x 10(9) (p,p'-DDD), and 8.95 x 10(-4) Pa (p,p'-DDD) to 1.08 x 10(-1) Pa (alpha-HCH), respectively. The K(OA) and P(L) data were compared with published data. The K(OA) values of o,p'-DDT at 25 degrees C were 3.23 x 10(9), higher than o,p'-DDE (1.02 x 10(9)) and o,p'-DDD (2.01 x 10(9)), indicating o,p'-DDT were more preferred to partition in soil compared with the metabolites. The K(OA) values were lower and P(L) values were higher for o,p'-DDE and o,p'-DDD, compared with their p,p'-isomeric counterparts, leading to a potential difference in behavior and fate of these isomers. The discrepancies among chemicals are obvious, which reflected in the increasing K(OA) and decreasing P(L) values in order of alpha-HCH, gamma-HCH, beta-HCH, delta-HCH, o,p'-DDE, p,p'-DDE, o,p'-DDD, o,p'-DDT, p,p'-DDD. For each compound, the LogK(OA) decreased linearly with reciprocal absolute temperature, while LogP(L) had a significant positive correlation with the inverse absolute temperature. The present study suggested that the method of gas chromatographic retention time was appropriate to measure the K(OA) and P(L) of a number of OCPs.

  2. A study of vapor bubble departure in subcooled flow boiling at low pressure

    International Nuclear Information System (INIS)

    Donevski, Bozin; Saga, Tetsuo; Kobayashi, Toshio; Segawa, Shigeki

    1999-01-01

    An experimental study of vapor bubble dynamics in sub-cooled flow boiling was conducted using the flow visualization and digital image processing methods. Vapor bubble departure departure in subcooled flow boiling have been experimentally investigated over a range of mass flux G=0.384 (kg/m 2 s), and heat flux q w = 27.2 x 10 4 (W/m 2 ), for the subcooled flow boiling region. It has been observed that once a vapor bubble departs from a nucleation site, it typically slides along the heating surface at sonic finite distance down-stream of nucleation site. The image processing method proposed in this study is based on the detachment and tracing of the edges of the bubbles and their background. The proposed method can be used in various fields of engineering applications. (Original)

  3. 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

  4. Organizational Leadership and Adaptive Reserve in Blood Pressure Control: The Heart Health NOW Study.

    Science.gov (United States)

    Henderson, Kamal H; DeWalt, Darren A; Halladay, Jacquie; Weiner, Bryan J; Kim, Jung I; Fine, Jason; Cykert, Samuel

    2018-04-01

    Our purpose was to assess whether a practice's adaptive reserve and high leadership capability in quality improvement are associated with population blood pressure control. We divided practices into quartiles of blood pressure control performance and considered the top quartile as the benchmark for comparison. Using abstracted clinical data from electronic health records, we performed a cross-sectional study to assess the association of top quartile hypertension control and (1) the baseline practice adaptive reserve (PAR) scores and (2) baseline practice leadership scores, using modified Poisson regression models adjusting for practice-level characteristics. Among 181 practices, 46 were in the top quartile, which averaged 68% or better blood pressure control. Practices with higher PAR scores compared with lower PAR scores were not more likely to reside in the top quartile of performance (prevalence ratio [PR] = 1.92 for highest quartile; 95% CI, 0.9-4.1). Similarly, high quality improvement leadership capability compared with lower capability did not predict better blood pressure control performance (PR = 0.94; 95% CI, 0.57-1.56). Practices with higher proportions of commercially insured patients were more likely than practices with lower proportions of commercially insured patients to have top quartile performance (37% vs 26%, P =.002), whereas lower proportions of the uninsured (8% vs 14%, P =.055) were associated with better performance. Our findings show that adaptive reserve and leadership capability in quality improvement implementation are not statistically associated with achieving top quartile practice-level hypertension control at baseline in the Heart Health NOW project. Our findings, however, may be limited by a lack of patient-related factors and small sample size to preclude strong conclusions. © 2018 Annals of Family Medicine, Inc.

  5. Isobaric low pressure vapor-liquid equilibrium data for the binary system monochloroacetic acid + dichloroacetic acid

    NARCIS (Netherlands)

    Londono, A.; Jongmans, Mark; Schuur, Boelo; de Haan, A.B.

    2012-01-01

    Isobaric vapor–liquid equilibrium (VLE) data for the binary system monochloroacetic acid + dichloroacetic acid have been measured at 5, 7.5, and 10 kPa. The VLE data measured in this work is thermodynamically consistent according to the Herington area method. The non-ideal behavior in the vapor

  6. 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.)

  7. Oxygen source-oriented control of atmospheric pressure chemical vapor deposition of VO2 for capacitive applications

    Directory of Open Access Journals (Sweden)

    Dimitra Vernardou

    2016-06-01

    Full Text Available Vanadium dioxides of different crystalline orientation planes have successfully been fabricated by chemical vapor deposition at atmospheric pressure using propanol, ethanol and O2 gas as oxygen sources. The thick a-axis textured monoclinic vanadium dioxide obtained through propanol presented the best electrochemical response in terms of the highest specific discharge capacity of 459 mAh g-1 with a capacitance retention of 97 % after 1000 scans under constant specific current of 2 A g-1. Finally, the electrochemical impedance spectroscopy indicated that the charge transfer of Li+ through the vanadium dioxide / electrolyte interface was easier for this sample enhancing significantly its capacitance performance.

  8. Vapor pressure prediction for alkenoic and aromatic organic compounds by a UNIFAC-based group contribution method

    Science.gov (United States)

    Asher, William E.; Pankow, James F.

    A UNIFAC-based group contribution method is developed for predicting liquid vapor pressure (pLo) values of organic compounds, including molecules containing C dbnd C bonds. The method is an extension of UNIFAC- pLo.1 as developed by Asher et al. [2002. Estimating the vapor pressures of multi-functional oxygen-containing organic compounds using group contribution methods, Atmospheric Environment 36, 1483-1498] in which C dbnd O is the only type of sp 2-bonded carbon considered. The current work is important due to the widespread interest in the physical behavior of organic compounds with sp 2 carbon-carbon bonds, e.g., alkenes and aromatics. In the context of particulate matter (PM) formation in the atmosphere, condensable molecules of interest that contain sp 2 bonds include initial oxidation products such as 4-oxo-but-2-enoic acid and 2,6-dihydroxybenzoic acid. UNIFAC- pLo.2 as developed here was based on experimentally determined, temperature-dependent pLo data for 39 alkene compounds, 26 aromatic compounds, and 81 saturated compounds. In order to check the method, an independent set of 22 alkene and 40 aromatic compounds with known volatilities was assembled. Vapor pressures for these compounds were estimated using UNIFAC- pLo.2 and the results compared to known values. The UNIFAC- pLo.2 method was found to predict vapor pressure within a factor of 1.8 and this accuracy was equal across the volatility range of the basis set (3×10 -10 - 3×10 -1 atm). The SPARC method [Hilal, S.H., Carreira, L.A., Karickhoff, S.W., 1994. Estimation of chemical reactivity parameters and physical properties of organic molecules using SPARC. In: Murray, P.P.A.J.S. (Ed.), Quantitative Treatments of Solute/Solvent Interactions. Elsevier, Amsterdam] was also used to estimate pLo for the 22 alkene and 40 aromatic compounds in the test set. Comparing the results of SPARC with UNIFAC- pLo.2 shows that the UNIFAC- pLo.2 method was on average 50% more accurate than the SPARC. The combined

  9. Very Long Single and Few-Walled Boron Nitride Nanotubes via the Pressurized Vapor/Condenser Method

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin C.; Park, Cheol; Kim, Jae-Woo; Lillehei, Peter T.; Crooks, Roy; Harrison, Joycelyn S.

    2009-01-01

    A new method for producing long, small diameter, single and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

  10. Physical and electrical properties of graphene grown under different hydrogen flow in low pressure chemical vapor deposition.

    Science.gov (United States)

    Hussain, Sajjad; Iqbal, Muhmmad Waqas; Park, Jaehyun; Ahmad, Muneer; Singh, Jai; Eom, Jonghwa; Jung, Jongwan

    2014-01-01

    Hydrogen flow during low pressure chemical vapor deposition had significant effect not only on the physical properties but also on the electrical properties of graphene. Nucleation and grain growth of graphene increased at higher hydrogen flows. And, more oxygen-related functional groups like amorphous and oxidized carbon that probably contributed to defects or contamination of graphene remained on the graphene surface at low H2 flow conditions. It is believed that at low hydrogen flow, those remained oxygen or other oxidizing impurities make the graphene films p-doped and result in decreasing the carrier mobility.

  11. Very long single- and few-walled boron nitride nanotubes via the pressurized vapor/condenser method

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Michael W. [NASA Langley Research Center, Hampton, VA (United States); Jordan, Kevin C. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Park, Cheol [NASA Langley Research Center, Hampton, VA (United States); Kim, Jae-Woo [NASA Langley Research Center, Hampton, VA (United States); Lillehei, Peter T. [NASA Langley Research Center, Hampton, VA (United States); Crooks, Roy [NASA Langley Research Center, Hampton, VA (United States); Harrison, Joycelyn S. [NASA Langley Research Center, Hampton, VA (United States)

    2009-11-01

    Boron nitride nanotubes (BNNTs) are desired for their exceptional mechanical, electronic, thermal, structural, textural, optical, and quantum properties. A new method for producing long, small-diameter, single- and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small-diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

  12. 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.

  13. Qualitative Resting Coronary Pressure Wave Form Analysis to Predict Fractional Flow Reserve.

    Science.gov (United States)

    Matsumura, Mitsuaki; Maehara, Akiko; Johnson, Nils P; Fearon, William F; De Bruyne, Bernard; Oldroyd, Keith G; Pijls, Nico H J; Jenkins, Paul; Ali, Ziad A; Mintz, Gary S; Stone, Gregg W; Jeremias, Allen

    2018-03-27

    To evaluate the predictability of resting distal coronary pressure wave forms for fractional flow reserve (FFR). Resting coronary wave forms were qualitatively evaluated for the presence of (i) dicrotic notch; (ii) diastolic dipping; and (iii) ventricularization. In a development cohort (n=88) a scoring system was developed that was then applied to a validation cohort (n=428) using a multivariable linear regression model to predict FFR and receiver operating characteristics (ROC) to predict FFR ≤0.8. In the development cohort, all 3 qualitative parameters were independent predictors of FFR. However, in a multivariable linear regression model in the validation cohort, qualitative wave form analysis did not further improve the ability of resting distal coronary to aortic pressure ratio (Pd/Pa) (p=0.80) or instantaneous wave-free ratio (iFR) (p=0.26) to predict FFR. Using ROC, the area under the curve of resting Pd/Pa (0.86 versus 0.86, P=0.08) and iFR (0.86 versus 0.86, P=0.26) did not improve by adding qualitative analysis. Qualitative coronary wave form analysis showed moderate classification agreement in predicting FFR but did not add substantially to the resting pressure gradients Pd/Pa and iFR; however, when discrepancies between quantitative and qualitative analyses are observed, artifact or pressure drift should be considered.

  14. 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

    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 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...

  15. Atmospheric pressure chemical vapor deposition (APCVD) grown bi-layer graphene transistor characteristics at high temperature

    KAUST Repository

    Qaisi, Ramy M.

    2014-05-15

    We report the characteristics of atmospheric chemical vapor deposition grown bilayer graphene transistors fabricated on ultra-scaled (10 nm) high-κ dielectric aluminum oxide (Al2O3) at elevated temperatures. We observed that the drive current increased by >400% as temperature increased from room temperature to 250 °C. Low gate leakage was maintained for prolonged exposure at 100 °C but increased significantly at temperatures >200 °C. These results provide important insights for considering chemical vapor deposition graphene on aluminum oxide for high temperature applications where low power and high frequency operation are required. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Improved Assessment Strategies for Vapor Intrusion Passive Samplers and Building Pressure Control

    Science.gov (United States)

    2013-09-01

    health risks via VI. 6 Several samplers have more than one configuration option. Some of the samplers offer models with different uptake rates to...available. The selection of the appropriate adsorbent media should be done by consulting with an experienced analytical chemist . The goal is to provide a...average human exposures, which are the basis of health risk assessment. For vapor intrusion investigations, target concentrations based on 25- to 30

  17. The association between blood pressure components and cognitive functions and cognitive reserve.

    Science.gov (United States)

    Alipour, Houman; Goldust, Mohamad

    2016-01-01

    Hypertension exerts a subtle impact on the brain that is revealed by diminished cognitive function. This study aimed at evaluating the association between blood pressure components and cognitive functions and cognitive reserve. In this cross-sectional study, 500 subjects from general population were evaluated. All neuropsychological tests were negatively associated with age; memory and executive function were also positively related with education. The hypertensives (HT) were less efficient than the normotensives (NT) in the test of memory with interference at 10 s (MI-10) (-32%, p = 0.043), clock drawing test (CLOX) (-26%, p cognitive reserve index (CRI) was 8% lower in the HT (p = 0.04) and was predicted by higher pulse BP (OR 0.86, p cognition, higher values of systolic BP being associated to impaired cognitive function.

  18. Comparison of compensatory reserve during lower-body negative pressure and hemorrhage in nonhuman primates

    Science.gov (United States)

    Howard, Jeffrey T.; Mulligan, Jane; Grudic, Greg Z.; Convertino, Victor A.

    2016-01-01

    Compensatory reserve was measured in baboons (n = 13) during hemorrhage (Hem) and lower-body negative pressure (LBNP) using a machine-learning algorithm developed to estimate compensatory reserve by detecting reductions in central blood volume during LBNP. The algorithm calculates compensatory reserve index (CRI) from normovolemia (CRI = 1) to cardiovascular decompensation (CRI = 0). The hypothesis was that Hem and LBNP will elicit similar CRI values and that CRI would have higher specificity than stroke volume (SV) in predicting decompensation. Blood was removed in four steps: 6.25%, 12.5%, 18.75%, and 25% of total blood volume. Four weeks after Hem, the same animals were subjected to four levels of LBNP that was matched on the basis of their central venous pressure. Data (mean ± 95% confidence interval) indicate that CRI decreased (P < 0.001) from baseline during Hem (0.69 ± 0.10, 0.57 ± 0.09, 0.36 ± 0.10, 0.16 ± 0.08, and 0.08 ± 0.03) and LBNP (0.76 ± 0.05, 0.66 ± 0.08, 0.36 ± 0.13, 0.23 ± 0.11, and 0.14 ± 0.09). CRI was not different between Hem and LBNP (P = 0.20). Linear regression analysis between Hem CRI and LBNP CRI revealed a slope of 1.03 and a correlation coefficient of 0.96. CRI exhibited greater specificity than SV in both Hem (92.3 vs. 82.1) and LBNP (94.8 vs. 83.1) and greater ROC AUC in Hem (0.94 vs. 0.84) and LBNP (0.94 vs. 0.92). These data support the hypothesis that Hem and LBNP elicited the same CRI response, suggesting that measurement of compensatory reserve is superior to SV as a predictor of cardiovascular decompensation PMID:27030667

  19. Method for estimating critical properties of heavy compounds suitable for cubic equations of state and its application to the prediction of vapor pressures

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Ioannis, Smirlis; Iakovos, Yakoumis

    1997-01-01

    Cubic equations of state (EoS) are often used for correlating and predicting phase equilibria. Before extending any EoS to mixtures, reliable vapor-pressure prediction is essential. This requires experimental, if possible, critical temperatures T-c, pressures P-c, and acentric factor omega...... or extensive pure-compound vapor-pressure data which, for heavy and/or complex compounds, are often not available. This work presents a method for estimating T-c, P-c, and omega values for heavy compounds (typically with MW > 130) suitable for vapor-pressure calculations with generalized cubic Eo......S. The proposed scheme employs a recent group-contribution method (Constantinou et al. Fluid Phase Equilib. 1995, 103 (1), 11) for estimating the acentric factor. The two critical properties are estimated via a generalized correlation for the ratio T-c/P-c (with the van der Waals surface area) and the cubic Eo...

  20. 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.

  1. 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.

  2. Effect of iodine doping in the deposition solution and iodine vapor pressure in the sensitization treatment on the properties of PbSe films

    Science.gov (United States)

    Suh, Youngjoon; Suh, Sang-Hee

    2017-09-01

    Effect of iodine-doping in the deposition solution and iodine vapor pressure during the sensitization process on the morphological, microstructural, electrical, and optical properties of PbSe films was studied. Undoped and iodine-doped PbSe films of polycrystalline particles were coated on thermally oxidized silicon substrates by chemical bath deposition. The PbSe films were oxidized at 380°C for 30 min and then iodinated at different iodine vapor pressures at 380°C for 5 min. When the iodine vapor pressure was below 20 Pa, PbSeO3 was the main phase formed on the surface of PbSe microcrystals for both undoped and iodine-doped films. As the iodine vapor pressure was increased above 20 Pa, Pb3I2O2 and PbI2 phases were formed in both types of films and PbSeO3 disappeared in the undoped film. Only the iodine-doped films showed photo response. The sheet resistance and IR signal-to-noise ratio had maximum values at the iodine vapor pressure of 17.5 Pa in the iodine-doped film. The x-ray diffraction spectra, scanning electron microscopy morphologies, and EDS analyses of the sensitized PbSe films show that the main role of iodine in the sensitization is helping solid-state sintering of PbSe microcrystals which may lead to redistribution of oxygen atoms in the effective atomic sites.

  3. 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.

  4. Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

    KAUST Repository

    Qaisi, Ramy M.

    2013-04-01

    Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

  5. 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.

  6. Determinação da pressão de vapor de compostos orgânicos por cromatografia gasosa Determination of vapor pressure of organic compounds by gas chromatography

    Directory of Open Access Journals (Sweden)

    Fabrício P. Povh

    2006-06-01

    Full Text Available O conhecimento das pressões de vapor dos compostos naturais e suas propriedades críticas, de grande interesse para a extração supercrítica e impregnação de polímeros pelo processo supercrítico, é imprescindível para se fazer a modelagem termodinâmica do equilíbrio de fases. No entanto, a escassez de dados experimentais desses compostos, devida à alta volatilidade, ou facilidade à degradação em temperaturas baixas, requer a utilização de métodos especiais. Neste trabalho, determinaram-se as pressões de vapor da curcumina, nicotina, d-limoneno, beta-mirceno, citronelal e linalol, através de um método que utiliza medidas de tempo de retenção por cromatografia gasosa. Utilizou-se detector de ionização de chama e coluna em fase estacionária não polar, em condições isotérmicas. O método apresenta vantagens em relação a outros métodos, quanto à rapidez de análise, quantidade e repetibilidade das amostras. Para as determinações das pressões de vapor destes compostos naturais requer-se o conhecimento da temperatura normal de ebulição, ou temperatura de fusão e das pressões de vapor dos homólogos dos compostos analisados.The knowledge of the vapor pressures of natural compounds, as well as their critical properties are of great interest for the application of supercritical extraction and supercritical impregnation dye, and necessary for the thermodynamic modeling of equilibria phase. The scarcity of experimental data for these compounds results from their low volatility or easiness to degrade at low temperatures, therefore, requires the use of special methods. In this work, the vapor pressures of curcumin, nicotine, d-limonene, ß-myrcene, citronellal and linalool were determined through a method based on the retention time in a gas chromatographer column. A flame ionization detector and a column with non-polar stationary phase were used, under isothermal conditions. This method has the advantages of giving

  7. Vascular flow reserve as a link between long-term blood pressure level and physical performance capacity in mammals

    DEFF Research Database (Denmark)

    Poulsen, Christian B; Damkjær, Mads; Hald, Bjørn O

    2016-01-01

    Mean arterial pressure (MAP) is surprisingly similar across different species of mammals, and it is, in general, not known which factors determine the arterial pressure level. Mammals often have a pronounced capacity for sustained physical performance. This capacity depends on the vasculature...... having a flow reserve that comes into play as tissue metabolism increases. We hypothesize that microvascular properties allowing for a large vascular flow reserve is linked to the level of the arterial pressure.To study the interaction between network properties and network inlet pressure, we developed...

  8. 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.

  9. Facile Fabrication of Boron-Doped Titania Nanopowders by Atmospheric Pressure Chemical Vapor Synthesis Route and its Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    K. Saberyan

    2014-04-01

    Full Text Available The Atmospheric Pressure Chemical Vapor Synthesis (APCVS route is a process that can be used for the synthesis of doped-nanocrystalline powders with very small crystallite sizes having a narrow particle size distribution and high purity. In this study, APCVS technique was used to prepare boron-doped titania nanopowders. The effects of temperature, borate flow rate and water flow rate on the amount of doped boron were studied. The resultant powders were characterized by inductively coupled plasma (ICP, X-ray diffraction (XRD, nitrogen adsorption technique (BET, UV-visible DRS spectroscopy, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. The optimum boron precursor flow rate was 80 sccm. The highest amount of doped boron was attained when water flow rate was 900 sccm. In comparison to the pristine TiO2, the boron-doped TiO2 nanoparticles showed blue-shift in band-gap energy of the samples.

  10. Optimization of selective area growth of GaAs by low pressure organometallic vapor phase epitaxy for monolithic integrated circuits

    Science.gov (United States)

    Kanber, H.; Bar, S. X.; Norris, P. E.; Beckham, C.; Pacer, M.

    1994-02-01

    GaAs MESFET device structures have been grown on silicon nitride or silicon dioxide masked 50 and 76 mm GaAs substrates by low pressure organometallic vapor phase epitaxy. Very smooth, featureless morphology and 100 percent selectivity of GaAs islands have been achieved over a range of growth conditions. Optimization of the GaAs p-buffer of the field effect transistor structure has led to improved device performance, including increased breakdown voltage. Device characteristics of the 0.5 μm gate low noise metal semiconductor field-effect transistors fabricated on these islands show good performance and wafer to wafer reproducibility on the second device lot.

  11. On the Origin of Light Emission in Silicon Rich Oxide Obtained by Low-Pressure Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    M. Aceves-Mijares

    2012-01-01

    Full Text Available Silicon Rich Oxide (SRO has been considered as a material to overcome the drawbacks of silicon to achieve optical functions. Various techniques can be used to produce it, including Low-Pressure Chemical Vapor Deposition (LPCVD. In this paper, a brief description of the studies carried out and discussions of the results obtained on electro-, cathode-, and photoluminescence properties of SRO prepared by LPCVD and annealed at 1,100°C are presented. The experimental results lead us to accept that SRO emission properties are due to oxidation state nanoagglomerates rather than to nanocrystals. The emission mechanism is similar to Donor-Acceptor decay in semiconductors, and a wide emission spectrum, from 450 to 850 nm, has been observed. The results show that emission is a function of both silicon excess in the film and excitation energy. As a result different color emissions can be obtained by selecting the suitable excitation energy.

  12. Atmospheric-pressure epitaxial growth technique of a multiple quantum well by mist chemical vapor deposition based on Leidenfrost droplets

    Science.gov (United States)

    Kawaharamura, Toshiyuki; Dang, Giang T.; Nitta, Noriko

    2016-10-01

    A multiple quantum well α-Fe2O3/α-Ga2O3 with parallel and coherent formation of uniform and highly single-crystalline layers on a sapphire substrate has been fabricated by open-air atmospheric-pressure solution-processed mist chemical vapor deposition (Mist CVD). This report demonstrates that complicated structures with atomic-level control can be fabricated even in non-vacuum conditions by the Mist CVD. This can be achieved via the precise control of the precursor flow and ambient temperature combined with the formation of mist droplets of the special Leidenfrost state, which increased the atomic migration length by 108 times more than that of traditional vacuum techniques. This work could be a milestone in the transformation from vacuum to non-vacuum thin film deposition techniques towards a green and sustainable industry.

  13. TG-based transpiration techniques for the determination of equilibrium vapor pressure of zirconium volatile complex for MOCVD applications

    International Nuclear Information System (INIS)

    Arul Jeevan, T.S.; Nagaraja, K.S.; Mathews, Tom; Raghunathan, V.S.

    2008-01-01

    The metallo-organic complex of Zr (tmhd) 4 tetrakis 2,2,6,6-tetramethylheptanedionato) zirconium(IV) was synthesized and it can be identified as an ideal precursor. The thermal stability and complete volatility of this precursor was verified from thermo gravimetric analysis and characterized by elemental analyses. The monomeric structure of the complex was confirmed by electronspray-ionization mass spectroscopy. The vapor pressure measurement was carried out by TG-based transpiration technique and the enthalpy of sublimation was calculated from the slope of Clausius-Clapeyron equation. This yielded a value of 89.0 kJ.mol -1 for the standard enthalpy of sublimation over the temperature span of 411-463K. (author)

  14. Vapor pressures of 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids with long alkyl chains

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Marisa A. A., E-mail: lbsantos@fc.up.pt, E-mail: marisa.alexandra.rocha@gmail.com [Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); Coutinho, João A. P. [CICECO, Departamento de Química, Universidade de Aveiro, P-3810-193 Aveiro (Portugal); Santos, Luís M. N. B. F., E-mail: lbsantos@fc.up.pt, E-mail: marisa.alexandra.rocha@gmail.com [Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2014-10-07

    This work presents the vapor pressure at several temperatures for the 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide series, [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (N = 14, 16, 18, and 20), measured by a Knudsen effusion method combined with a quartz crystal microbalance. The thermodynamic properties of vaporization of the ionic liquids under study are analysed together with the results obtained previously for the shorter alkyl chain length [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (N = 2, 4, 6, 8, 10, and 12), in order to evaluate the effect of the alkyl side chains of the cation and to get additional insights concerning the nanostructuration of ionic liquids. The symmetry effect is explored, based on the comparison with the asymmetric imidazolium based ionic liquids, [C{sub N-1}C{sub 1}im][NTf{sub 2}]. A trend shift on the thermodynamic properties of vaporization along the alkyl side chains of the extended symmetric ionic liquids, around [C{sub 6}C{sub 6}im][NTf{sub 2}], was detected. An intensification of the odd-even effect was observed starting from [C{sub 6}C{sub 6}im][NTf{sub 2}], with higher enthalpies and entropies of vaporization for the odd numbered ionic liquids, [C{sub 7}C{sub 7}im][NTf{sub 2}] and [C{sub 9}C{sub 9}im][NTf{sub 2}]. Similar, but less pronounced, odd-even effect was found for the symmetric ionic liquids with lower alkyl side chains length, [C{sub N/2}C{sub N/2}im][NTf{sub 2}] (with N = 4, 6, 8, 10, and 12). This effect is related with the predominant orientation of the terminal methyl group of the alkyl chain to the imidazolium ring and their influence in the cation-anion interaction. The same Critical Alkyl length at the hexyl, (C{sub 6}C{sub 1}and C{sub 6}C{sub 6}) was found for both asymmetric and symmetric series indicating that the nanostructuration of the ionic liquids is related with alkyl chain length.

  15. 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.

  16. Modeling and Real-Time Process Monitoring of Organometallic Chemical Vapor Deposition of III-V Phosphides and Nitrides at Low and High Pressure

    Science.gov (United States)

    Bachmann, K. J.; Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Sukidi, N.; McCall, S.

    1999-01-01

    The purpose of this paper is to review modeling and real-time monitoring by robust methods of reflectance spectroscopy of organometallic chemical vapor deposition (OMCVD) processes in extreme regimes of pressure. The merits of p-polarized reflectance spectroscopy under the conditions of chemical beam epitaxy (CBE) and of internal transmission spectroscopy and principal angle spectroscopy at high pressure are assessed. In order to extend OMCVD to materials that exhibit large thermal decomposition pressure at their optimum growth temperature we have designed and built a differentially-pressure-controlled (DCP) OMCVD reactor for use at pressures greater than or equal to 6 atm. We also describe a compact hard-shell (CHS) reactor for extending the pressure range to 100 atm. At such very high pressure the decomposition of source vapors occurs in the vapor phase, and is coupled to flow dynamics and transport. Rate constants for homogeneous gas phase reactions can be predicted based on a combination of first principles and semi-empirical calculations. The pressure dependence of unimolecular rate constants is described by RRKM theory, but requires variational and anharmonicity corrections not included in presently available calculations with the exception of ammonia decomposition. Commercial codes that include chemical reactions and transport exist, but do not adequately cover at present the kinetics of heteroepitaxial crystal growth.

  17. Estimating the vapor pressures of multi-functional oxygen-containing organic compounds using group contribution methods

    Science.gov (United States)

    Asher, William E.; Pankow, James F.; Erdakos, Garnet B.; Seinfeld, John H.

    A UNIFAC-based method for estimating the vapor pressure ( pLo) values of oxygen-containing compounds of intermediate-to-low volatility has been developed as an aid in modeling the formation and behavior of organic aerosols. This UNIFAC- pLo method was constructed using a set of 76 compounds with experimentally determined pLo values. The compounds chosen are of intermediate-to-low volatility and contain multiple oxygen-containing functionalities. For test and development purposes, the 76 compounds were divided into a basis set of 43 compounds used to generate the coefficients required in the UNIFAC- pLo method and a second set of 33 compounds that was used to test the coefficients generated using the basis set. Both the basis and test sets contained compounds that possessed similar structures and functionalities. For the 33 compounds in the test set, on average UNIFAC- pLo predicted the pLo values to within a factor of 2 over the temperature range 290-320 K. Furthermore, the UNIFAC- pLo method did not show any correlation in prediction error with pLo so that it was equally likely to underpredict as overpredict pLo regardless of volatility. For comparison, three other vapor pressure estimation methods were applied to the test set of compounds. On average, these other methods all predicted the test set pLo values to within a factor of 3 over the temperature range 290-320 K. In contrast to the UNIFAC- pLo method, the prediction errors from the methods were found to be correlated with pLo so that the other methods overpredicted pLo as volatility decreased.

  18. High-pressure vapor-liquid equilibrium data for CO2-orange peel oil

    Directory of Open Access Journals (Sweden)

    G.R. Stuart

    2000-06-01

    Full Text Available Recently, there has been a growing interest in fractionating orange peel oil by the use of supercritical carbon dioxide (SCCO2. However, progress in this area has been hindered by the lack of more comprehensive work concerning the phase equilibrium behavior of the SCCO2-orange peel oil system. In this context, the aim of this work is to provide new phase equilibrium data for this system over a wide range of temperatures and pressures, permitting the construction of coexistence PT-xy curves as well as the P-T diagram. The experiments were performed in a high-pressure variable-volume view cell in the temperature range of 50-70ºC from 70 to 135 atm and in the CO2 mass fraction composition range of 0.35-0.98. Based on the experimental phase equilibrium results, appropriate operating conditions can be set for high-pressure fractionation purposes.

  19. 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

  20. Studies of air, water, and ethanol vapor atmospheric pressure plasmas for antimicrobial applications.

    Science.gov (United States)

    Ferrell, James R; Bogovich, Erinn R; Lee, Nicholas R; Gray, Robert L; Pappas, Daphne D

    2015-06-25

    The generation of air-based plasmas under atmospheric plasma conditions was studied to assess their antimicrobial efficacy against commonly found pathogenic bacteria. The mixture of initial gases supplied to the plasma was found to be critical for the formation of bactericidal actives. The optimal gas ratio for bactericidal effect was determined to be 99% nitrogen and 1% oxygen, which led to a 99.999% reduction of a pathogenic strain of Escherichia coli on stainless steel surfaces. The experimental substrate, soil load on the substrate, flow rate of the gases, and addition of ethanol vapor all were found to affect antimicrobial efficacy of studied plasmas. Optical emission spectroscopy was used to identify the species that were present in the plasma bulk phase for multiple concentrations of nitrogen and oxygen ratios. The collected spectra indicate a unique series of bands present in the ultraviolet region of the electromagnetic spectrum that can be attributed to nitric oxide species known to be highly antimicrobial. This intense spectral profile dramatically changes as the concentration of nitrogen decreases.

  1. 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

  2. Identifying Liquid-Gas System Misconceptions and Addressing Them Using a Laboratory Exercise on Pressure-Temperature Diagrams of a Mixed Gas Involving Liquid-Vapor Equilibrium

    Science.gov (United States)

    Yoshikawa, Masahiro; Koga, Nobuyoshi

    2016-01-01

    This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…

  3. Characterization of atmospheric pressure plasma treated pure cashmere and wool/cashmere textiles: Treatment in air/water vapor mixture

    Energy Technology Data Exchange (ETDEWEB)

    Zanini, Stefano, E-mail: stefano.zanini@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Grimoldi, Elisa [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy); Citterio, Attilio [Politecnico di Milano, Dipartimento di Chimica, Materiali ed Ingegneria Chimica “G. Natta”, Via Mancinelli 7, I-20131 Milano (Italy); Riccardi, Claudia, E-mail: riccardi@mib.infn.it [Università degli Studi di Milano-Bicocca, Dipartimento di Fisica “G. Occhialini”, p.za della Scienza, 3, I-20126 Milano (Italy)

    2015-09-15

    Highlights: • We treated cashmere and wool/cashmere textiles with atmospheric pressure plasma. • Wettability of the fabrics was increased. • The increment in wettability derived from a surface oxidation of the fibers. • Only minor etching effects were observed with scanning electron microscopy. - Abstract: We performed atmospheric pressure plasma treatments of pure cashmere and wool/cashmere textiles with a dielectric barrier discharge (DBD) in humid air (air/water vapor mixtures). Treatment parameters have been optimized in order to enhance the wettability of the fabrics without changing their bulk properties as well as their touch. A deep characterization has been performed to study the wettability, the surface morphologies, the chemical composition and the mechanical properties of the plasma treated textiles. The chemical properties of the plasma treated samples were investigated with attenuated total reflectance Fourier transform infrared (FTIR/ATR) spectroscopy and X-ray photoelectron microscopy (XPS). The analyses reveal a surface oxidation of the treated fabrics, which enhances their surface wettability. Morphological characterization of the treated fibers with scanning electron microscopy (SEM) reveals minor etching effects, an essential feature for the maintenance of the textile softness.

  4. Experimental results for hydrocarbon refrigerant vaporization inside brazed plate heat exchangers at high pressure

    DEFF Research Database (Denmark)

    Desideri, Adriano; Ommen, Torben Schmidt; Wronski, Jorrit

    2016-01-01

    power unit. In this contribution the preliminary experimental results obtained from the first experimental campaign carried out on the rig are reported. HFC-134a was selected as working fluid. The experiments were carried out at saturation temperature of 60, 70 and 80 °C and inlet and outlet qualities...... and was characterized by a decreasing trend with respect to the mean evaporator quality.The frictional pressure drop showed a linear dependence on the mean quality value and increased as the saturation temperature decreased. The experimental heat transfer coefficients were compared with a well-known correlation...

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

    Czech Academy of Sciences Publication Activity Database

    Straňák, V.; Herrendorf, A.-P.; Drache, S.; Čada, Martin; Hubička, Zdeněk; Tichý, M.; Hippler, R.

    2012-01-01

    Roč. 100, č. 14 (2012), "141604-1"-"141604-3" ISSN 0003-6951 R&D Projects: GA TA ČR TA01010517; GA ČR(CZ) GAP205/11/0386; GA ČR GAP108/12/1941 Institutional research plan: CEZ:AV0Z10100522 Keywords : magnetron * ECWR * low-pressure * sputtering * plasma diagnostics Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.794, year: 2012 http://dx.doi.org/10.1063/1.3699229

  6. Three-dimensional modelling of horizontal chemical vapor deposition. I - MOCVD at atmospheric pressure

    Science.gov (United States)

    Ouazzani, Jalil; Rosenberger, Franz

    1990-01-01

    A systematic numerical study of the MOCVD of GaAs from trimethylgallium and arsine in hydrogen or nitrogen carrier gas at atmospheric pressure is reported. Three-dimensional effects are explored for CVD reactors with large and small cross-sectional aspect ratios, and the effects on growth rate uniformity of tilting the susceptor are investigated for various input flow rates. It is found that, for light carrier gases, thermal diffusion must be included in the model. Buoyancy-driven three-dimensional flow effects can greatly influence the growth rate distribution through the reactor. The importance of the proper design of the lateral thermal boundary conditions for obtaining layers of uniform thickness is emphasized.

  7. Effect of water vapor on sound absorption in nitrogen at low frequency/pressure ratios

    Science.gov (United States)

    Zuckerwar, A. J.; Griffin, W. A.

    1981-01-01

    Sound absorption measurements were made in N2-H2O binary mixtures at 297 K over the frequency/pressure range f/P of 0.1-2500 Hz/atm to investigate the vibrational relaxation peak of N2 and its location on f/P axis as a function of humidity. At low humidities the best fit to a linear relationship between the f/P(max) and humidity yields an intercept of 0.013 Hz/atm and a slope of 20,000 Hz/atm-mole fraction. The reaction rate constants derived from this model are lower than those obtained from the extrapolation of previous high-temperature data.

  8. Thermodynamics of the multicomponent vapor-liquid equilibrium under capillary pressure difference

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2001-01-01

    We discuss the two-phase multicomponent equilibrium, provided that the phase pressures are different due to the action of capillary forces. We prove the two general properties of such an equilibrium, which have previously been known for a single-component case, however, to the best of our knowledge......, not for the multicomponent mixtures. The importance is emphasized on the space of the intensive variables P, T and mu (i), where the laws of capillary equilibrium have a simple geometrical interpretation. We formulate thermodynamic problems specific to such an equilibrium, and outline changes to be introduced to common...... algorithms of flash calculations in order to solve these problems. Sample calculations show large variation of the capillary properties of the mixture in the very neighborhood of the phase envelope and the restrictive role of the spinodal surface as a boundary for possible equilibrium states with different...

  9. Application of the Transpiration Method To Determine the Vapor Pressure and Related Physico-Chemical Data of Low Volatile, Thermolabile, and Toxic Organo(thio)phosphates.

    Science.gov (United States)

    Althoff, Marc A; Grieger, Kathrin; Härtel, Martin A C; Karaghiosoff, Konstantin L; Klapötke, Thomas M; Metzulat, Manfred

    2017-04-06

    The present work represents the most recent study on the physico-chemical properties of the organophosphate compound class being directly related to the Chemical Weapons Convention (CWC). This compound class is of great importance in the ongoing conflict in Syria. Here, the vapor pressure of the deadly organo(thio)phosphate Amiton and seven of its derivatives was investigated. These medium to low volatile analytes pose a potential threat toward human life by inhalation or direct contact with the skin at very low doses. Therefore, the vapor pressures in ambient temperature regimes were measured by utilizing the transpiration method to determine the saturation vapor pressure p sat and the enthalpy of vaporization Δ l g H m ° at 298.15 K. We also successfully applied the transpiration method for the examination of thermolabile compounds. In particular, five of the molecules can undergo a thiono-thiolo rearrangement at elevated temperatures within a couple of hours and thus could possibly alter in the course of the experiment. In addition we demonstrate that the concentration under diffusion conditions, c dif , is a useful parameter for the choice of suitable gas phase detection equipment for Amiton and its derivatives, because it can be directly compared with the limit of detection LOD [ng L -1 ] of the device used. Finally, we proved the transpiration method to be applicable for the investigation of toxic and also high boiling and even thermolabile chemicals in general.

  10. 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

    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....... 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......-T data automatically during slow heating and cooling. The generated data are subjected to regression analysis leading to very close curve fitting of the P-T data and enabling appropriate enthalpy and entropy computations. The TPA system's absolute accuracy is checked by generating P-T data for pure water...

  11. 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

  12. Activity coefficients and free energies of nonionic mixed surfactant solutions from vapor-pressure and freezing-point osmometry.

    Science.gov (United States)

    MacNeil, Jennifer A; Ray, Gargi Basu; Leaist, Derek G

    2011-05-19

    The thermodynamic properties of mixed surfactant solutions are widely investigated, prompted by numerous practical applications of these systems and by interest in molecular association and self-organization. General techniques for measuring thermodynamic activities, such as isopiestic equilibration, are well-established for multicomponent solutions. Surprisingly, these techniques have not yet been applied to mixed surfactant solutions, despite the importance of the free energy for micelle stability. In this study, equations are developed for the osmotic coefficients of solutions of nonionic surfactant A + nonionic surfactant B. A mass-action model is used, with virial equations for the activity coefficients of the micelles and free surfactant monomer species. The equations are fitted to osmotic coefficients of aqueous decylsulfobetaine + dodecylsulfobetaine solutions measured by vapor-pressure and freezing-point osmometry. Equilibrium constants for mixed-micelle formation are calculated from the free monomer concentrations at the critical micelle concentrations. The derived activity coefficients of the micelles and free monomers indicate large departures from ideal solution behavior, even for dilute solutions of the surfactants. Stoichiometric activity coefficients of the total surfactant components are evaluated by Gibbs-Duhem integration of the osmotic coefficients. Relatively simple colligative property measurements hold considerable promise for free energy studies of multicomponent surfactant solutions. © 2011 American Chemical Society

  13. High Temperature Nanocomposites For Nuclear Thermal Propulsion and In-Space Fabrication by Hyperbaric Pressure Laser Chemical Vapor Deposition

    Science.gov (United States)

    Maxwell, J. L.; Webb, N. D.; Espinoza, M.; Cook, S.; Houts, M.; Kim, T.

    Nuclear Thermal Propulsion (NTP) is an indispensable technology for the manned exploration of the solar system. By using Hyperbaric Pressure Laser Chemical Vapor Deposition (HP-LCVD), the authors propose to design and build a promising next-generation fuel element composed of uranium carbide UC embedded in a latticed matrix of highly refractory Ta4HfC5 for an NTP rocket capable of sustaining temperatures up to 4000 K, enabling an Isp of up to 1250 s. Furthermore, HP-LCVD technology can also be harnessed to enable 3D rapid prototyping of a variety of materials including metals, ceramics and composites, opening up the possibility of in-space fabrication of components, replacement parts, difficult-to-launch solar sails and panels and a variety of other space structures. Additionally, rapid prototyping with HP-LCVD makes a feasible "live off the land" strategy of interplanetary and interstellar exploration ­ the precursors commonly used in the technology are found, often in abundance, on other solar system bodies either as readily harvestable gas (e.g. methane) or as a raw material that could be converted into a suitable precursor (e.g. iron oxide into ferrocene on Mars).

  14. Atmospheric pressure chemical vapor deposition mechanism of Al 2O 3 film from AlCl 3 and O 2

    Science.gov (United States)

    Nasution, Indra; Velasco, Angelito; Kim, Hee-joon

    2009-01-01

    Aluminum oxide (Al 2O 3) films were deposited by atmospheric pressure chemical vapor deposition (AP-CVD) method from aluminum trichloride (AlCl 3), argon, and oxygen gas mixtures at temperatures ranging from 800 to 1000 °C. Alumina films with crystalline phases of γ- or θ-, and α-alumina were obtained starting at 800 °C. Increase in the relative amount of the α-phase as well as improvement in crystallinity is observed as temperature is increased to 1000 °C. The films have low chlorine content, which continued to decrease with increasing temperature. Analysis of the film growth rate on tubular substrates of varying diameters revealed a diffusion-limited growth from 800 to 950 °C and gas-phase reaction-limited growth at 1000 °C. The growth species is a cluster with size 1.2 nm at 800 °C and 0.9 nm at 950 °C. The gas-phase reaction constant at 1000 °C is 1.1/s.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-09-01

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

  16. Polarization memory of blue and red luminescence from nanocrystalline porous silicon treated by high-pressure water vapor annealing

    International Nuclear Information System (INIS)

    Gelloz, B.; Koyama, H.; Koshida, N.

    2008-01-01

    The polarization memory (PM) effect in the blue and red photoluminescence (PL) of p-type porous Si (PS) treated by high-pressure water vapor annealing (HWA) has been investigated. HWA induces a significant blue PL emission at about 450 nm, together with a drastic enhancement of the red PL intensity. The polarization memory of the red emission band is anisotropic and is in agreement with emission from quantum sized Si nanocrystals, whereas that of the blue band is high and isotropic, indicating an emission mechanism related to localized states in the amorphous Si oxide surrounding the Si skeleton of the PS layer after HWA. HWA does not induce any blue emission in PS that was electrochemically oxidized (ECO) beforehand because the electrochemically grown oxide tends to prevent the formation of blue-emitting amorphous oxide upon HWA. The PM of ECO-PS at low emission energies is anisotropic, but in a direction 45 deg. rotated compared to that of PS treated by HWA. This unique behavior may be related to the electrical nature of electrochemical oxidation. HWA increases the PM of ECO-PS. This could be attributed to the enhanced passivation induced by HWA

  17. Photocatalytic reaction characteristics of the titanium dioxide supported on the long phosphorescent phosphor by a low pressure chemical vapor deposition.

    Science.gov (United States)

    Kim, Jung-Sik; Kim, Seung-Woo; Jung, Sang-Chul

    2014-10-01

    This study investigated the photocatalytic behavior of titanium dioxide (TiO2)-supported on the long phosphorescent materials. Nanocrystalline TiO2 was directly deposited on the plate of alkaline earth aluminate phosphor, CaAl2O4: Eu2+, Nd3+ by a low pressure chemical vapor deposition (LPCVD). Photocatalytic reaction performance was examined with the decomposition of benzene gas by using a gas chromatography (GC) system under ultraviolet and visible light (λ > 410 nm) irradiations. The LPCVD TiO2-coated phosphors showed active photocatalytic reaction under visible irradiation. The mechanism of the photocatalytic reactivity for the TiO,-coated phosphorescent phosphor was discussed in terms of the energy band structure and phosphorescence. The coupling of TiO2 with phosphor may result in energy band bending in the junction region, which makes the TiO, crystal at the interface to be photo-reactive under visible light irradiation. The fastest degradation of ben- zene gas occurred for the TiO,-coated phosphor prepared with 1 min deposition time (-150 nm thickness). The LPCVD TiO,-coated phosphor is also photo-reactive under darkness through the light photons emitted from the CaAl2O4 phosphor. In addition, the TiO2-coated phosphorescent phosphors were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).

  18. Quantitative relationships for the prediction of the vapor pressure of some hydrocarbons from the van der Waals molecular surface

    Directory of Open Access Journals (Sweden)

    Olariu Tudor

    2015-01-01

    Full Text Available A quantitative structure - property relationship (QSPR modeling of vapor pressure at 298.15 K, expressed as log (VP / Pa was performed for a series of 84 hydrocarbons (63 alkanes and 21 cycloalkanes using the van der Waals (vdW surface area, SW/Å2, calculated by the Monte Carlo method, as the molecular descriptor. The QSPR model developed from the subset of 63 alkanes (C1-C16, deemed as the training set, was successfully used for the prediction of the log (VP / Pa values of the 21 cycloalkanes, which was the external prediction (test subset. A QSPR model was also developed for a series composed of all 84 hydrocarbons. Both QSPR models were statistically tested for their ability to fit the data and for prediction. The results showed that the vdW molecular surface used as molecular descriptor (MD explains the variance of the majority of the log (VP / Pa values in this series of 84 hydrocarbons. This MD describes very well the intermolecular forces that hold neutral molecules together. The clear physical meaning of the molecular surface values, SW/Å2, could explain the success of the QSPR models obtained with a single structural molecular descriptor.

  19. Photosynthesis Decrease and Stomatal Control of Gas Exchange in Abies alba Mill. in Response to Vapor Pressure Difference.

    Science.gov (United States)

    Guehl, J M; Aussenac, G

    1987-02-01

    The responses of steady state CO(2) assimilation rate (A), transpiration rate (E), and stomatal conductance (g(s)) to changes in leaf-to-air vapor pressure difference (DeltaW) were examined on different dates in shoots from Abies alba trees growing outside. In Ecouves, a provenance representative of wet oceanic conditions in Northern France, both A and g(s) decreased when DeltaW was increased from 4.6 to 14.5 Pa KPa(-1). In Nebias, which represented the dry end of the natural range of A. alba in southern France, A and g(s) decreased only after reaching peak levels at 9.0 and 7.0 Pa KPa(-1), respectively. The representation of the data in assimilation rate (A) versus intercellular CO(2) partial pressure (C(i)) graphs allowed us to determine how stomata and mesophyll photosynthesis interacted when DeltaW was increased. Changes in A were primarily due to alterations in mesophyll photosynthesis. At high DeltaW, and especially in Ecouves when soil water deficit prevailed, A declined, while C(i) remained approximately constant, which may be interpreted as an adjustment of g(s) to changes in mesophyll photosynthesis. Such a stomatal control of gas exchange appeared as an alternative to the classical feedforward interpretation of E versus DeltaW responses with a peak rate of E. The gas exchange response to DeltaW was also characterized by considerable deviations from the optimization theory of IR Cowan and GD Farquhar (1977 Symp Soc Exp Biol 31: 471-505).

  20. 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.

  1. Variability in Proline-Accumulating Ability of Barley (Hordeum vulgare L.) Cultivars Induced by Vapor Pressure Deficit 1

    Science.gov (United States)

    Naidu, Bodapati P.; Aspinall, Donald; Paleg, Leslie G.

    1992-01-01

    This work was undertaken in an effort to reconcile the conflicting proline-accumulating responses of the barley (Hordeum vulgare L.) cultivars, Excelsior and Proctor, reported by Singh et al. (1972) and Hanson et al. (1976). It deals with the effects of different vapor pressure deficits (VPD) during growth and subsequent drought stress on several barley cultivars. A higher VPD (1.2 kilopascals) during Clipper seedling growth resulted in higher solute-accumulating ability, seemingly independently of leaf water potential, than a lower VPD (0.12 kilopascals). The higher VPD during stress also resulted in higher solute contents, and this response may be more closely related to leaf water potential. When the responses of Excelsior and Proctor were examined in detail, it was found that the relative proline-accumulating ability of the two cultivars was dependent upon the VPD under which they were grown. At low VPD, Proctor accumulated significantly more proline than did Excelsior; whereas at higher VPD, Excelsior accumulated more proline than did Proctor. The crossover occurred at a VPD of about 0.72 kilopascals. This reversal of cultivar response was enhanced by multiplying seed under the two VPD extremes. Glycinebetaine accumulation did not demonstrate the crossover effect, although the concentration of this compound in all cultivars also depended on the VPD prevailing during growth and/or stress. Solute levels, in general, were more closely related to the decrease in relative water content than to a decrease in leaf water potential. It is concluded that the conflicting proline-accumulating responses of Excelsior and Proctor could be explained by these findings. PMID:16668700

  2. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    International Nuclear Information System (INIS)

    Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.

    2013-01-01

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called “interphase” between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC–TiC) n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC–TiC) n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  3. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Jacques, S., E-mail: jacques@lcts.u-bordeaux1.fr [LCTS, University of Bordeaux 1, CNRS, Herakles-Safran, CEA, 3 allee de la Boetie, F-33600 Pessac (France); Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P. [LCTS, University of Bordeaux 1, CNRS, Herakles-Safran, CEA, 3 allee de la Boetie, F-33600 Pessac (France)

    2013-06-15

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called “interphase” between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC–TiC){sub n} interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC–TiC){sub n} films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  4. Dynamic behavior of hydrogen in silicon nitride and oxynitride films made by low-pressure chemical vapor deposition

    Science.gov (United States)

    Arnoldbik, W. M.; Marée, C. H. M.; Maas, A. J. H.; van den Boogaard, M. J.; Habraken, F. H. P. M.; Kuiper, A. E. T.

    1993-08-01

    The diffusion and reactivity of hydrogen, incorporated in silicon oxynitride films during low-pressure chemical vapor deposition (LPCVD) at 800 °C, has been studied using elastic recoil detection and infrared spectroscopy for temperatures ranging from 700 to 1000 °C. The experiments are based on the determination of the hydrogen and deuterium depth profiles in layer structures in which H and D have been incorporated in different layers. This was achieved in two ways. Double layers have been produced directly during deposition or through exchange of incorporated hydrogen with gas-phase deuterium. The diffusion coefficient of hydrogen (or deuterium) is in the range between 3×1018 and 1×10-13 cm2/s, at temperatures between 700 and 1000 °C, and is characterized by a single activation energy of 3 eV, for [O]/([O]+[N]) values up to 0.45. The diffusion coefficient and hence the rate of the exchange of incorporated hydrogen and gas-phase deuterium increases with [O]/([O]+[N]) in the oxynitrides for [O]/([O]+[N]) >0.3. As a result we propose a model in which the rate-limiting step in the process of the diffusion of hydrogen in the LPCVD oxynitrides is the breaking of N-H bonds. Subsequent to the bond breaking, the hydrogen atom becomes trapped in a nitrogen-related trapping site or exchanges with a nitrogen-bonded hydrogen (deuterium) atom. If the bond breaking occurs within a distance of about 10 nm from the immediate surface, the hydrogen atom is able to desorb into the gas phase. A SiO2 capping layer is not able to prevent the desorption.

  5. Control of the nucleation and quality of graphene grown by low-pressure chemical vapor deposition with acetylene

    International Nuclear Information System (INIS)

    Yang, Meng; Sasaki, Shinichirou; Suzuki, Ken; Miura, Hideo

    2016-01-01

    Graphical abstract: - Highlights: • For the first time, we succeeded in the LPCVD growth of monolayer graphene using acetylene as the precursor gas. • The growth rate is very high when acetylene is used as the source gas. Our process has exhibited the potential to shorten the growth time of CVD graphene. • We found that the domain size, defects density, layer number and the sheet resistance of graphene can be changed by changing the acetylene flow rates. • We found that it is also possible to form bilayer graphene using acetylene. However, further study are necessary to reduce the defects density. - Abstract: Although many studies have reported the chemical vapor deposition (CVD) growth of large-area monolayer graphene from methane, synthesis of graphene using acetylene as the source gas has not been fully explored. In this study, the low-pressure CVD (LPCVD) growth of graphene from acetylene was systematically investigated. We succeeded in regulating the domain size, defects density, layer number and the sheet resistance of graphene by changing the acetylene flow rates. Scanning electron microscopy and Raman spectroscopy were employed to confirm the layer number, uniformity and quality of the graphene films. It is found that a low flow rate of acetylene (0.28 sccm) is required to form high-quality monolayer graphene in our system. On the other hand, the high acetylene flow rate (7 sccm) will induce the growth of the bilayer graphene domains with high defects density. On the basis of selected area electron diffraction (SAED) pattern, the as-grown monolayer graphene domains were analyzed to be polycrystal. We also discussed the relation between the sheet resistacne and defects density in graphene. Our results provide great insights into the understanding of the CVD growth of monolayer and bilayer graphene from acetylene.

  6. The influence of vapor pressure deficit (VPD) on the use of carbonyl sulfide (COS) as a photosynthetic tracer

    Science.gov (United States)

    Sun, W.; Maseyk, K. S.; Lett, C.; Seibt, U.

    2017-12-01

    Using carbonyl sulfide (COS) as a tracer to derive gross primary productivity (GPP) estimates requires knowledge of the relationship between leaf COS and CO2 uptake, which is typically embodied in a parameter called leaf relative uptake (LRU) ratio, defined as the concentration normalized COS:CO2 flux ratio. Previous laboratory and field studies have found light as the key environmental driver of LRU due to differential light responses of COS and CO2 uptake imposed by stomatal regulation. But the influences on LRU from other environmental drivers, particularly vapor pressure deficit (VPD) that affects stomatal conductance, remain elusive. Here we show that VPD is an important determinant of the COS-CO2 uptake relationship in a water-stressed ecosystem. We measured leaf COS and CO2 fluxes from a coast live oak with automated leaf chambers in spring 2013 in a southern Californian woodland. In this semiarid ecosystem, both leaf COS and CO2 uptake responded to VPD and showed a midday depression caused by reduced stomatal conductance. Above a moderate light level ( 500 µmol m-2 s-1), COS uptake decreased with light, whereas CO2 uptake saturated. As a result of the VPD-limited COS uptake, LRU value became smaller than 1.0 at high light (> 1000 µmol m-2 s-1), strongly deviating from previous laboratory values that converge to 1.6. Hence, failure to consider VPD influence may result in overestimated LRU value and underestimated CO2 uptake in this ecosystem. Using a coupled photosynthesis-stomatal conductance model, we show that the VPD control on LRU is in accordance with the response of stomatal conductance to VPD. Our results highlight that incorporating the VPD effect into the prediction of LRU value is crucial to the implementation of COS-based photosynthesis estimates in semiarid ecosystems.

  7. Using an Atmospheric Pressure Chemical Vapor Deposition Process for the Development of V2O5 as an Electrochromic Material

    Directory of Open Access Journals (Sweden)

    Dimitra Vernardou

    2017-02-01

    Full Text Available Vanadium pentoxide coatings were grown by atmospheric pressure chemical vapor deposition varying the gas precursor ratio (vanadium (IV chloride:water and the substrate temperature. All samples were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, cyclic voltammetry, and transmittance measurements. The water flow rate was found to affect the crystallinity and the morphological characteristics of vanadium pentoxide. Dense stacks of long grains of crystalline oxide are formed at the highest amount of water utilized for a substrate temperature of 450 °C. Accordingly, it was indicated that for higher temperatures and a constant gas precursor ratio of 1:7, the surface morphology becomes flattened, and columnar grains of uniform size and shape are indicated, keeping the high crystalline quality of the material. Hence, it was possible to define a frame of operating parameters wherein single-phase vanadium pentoxide may be reliably expected, including a gas precursor ratio of 1:7 with a substrate temperature of >450 °C. The as-grown vanadium pentoxide at 550 °C for a gas precursor ratio of 1:7 presented the best electrochemical performance, including a diffusion coefficient of 9.19 × 10−11 cm2·s−1, a charge density of 3.1 mC·cm−2, and a coloration efficiency of 336 cm2·C−1. One may then say that this route can be important for the growth of large-scale electrodes with good performance for electrochromic devices.

  8. Spatial and temporal changes in vapor pressure deficit and their impacts on crop yields in China during 1980-2008

    Science.gov (United States)

    Zhang, Shuai; Tao, Fulu; Zhang, Zhao

    2017-08-01

    Vapor pressure deficit (VPD) is a widely used measure of atmospheric water demand. It is closely related to crop evapotranspiration and consequently has major impacts on crop growth and yields. Most previous studies have focused on the impacts of temperature, precipitation, and solar radiation on crop yields, but the impact of VPD is poorly understood. Here, we investigated the spatial and temporal changes in VPD and their impacts on yields of major crops in China from 1980 to 2008. The results showed that VPD during the growing period of rice, maize, and soybean increased by more than 0.10 kPa (10 yr)-1 in northeastern and southeastern China, although it increased the least during the wheat growing period. Increases in VPD had different impacts on yields for different crops and in different regions. Crop yields generally decreased due to increased VPD, except for wheat in southeastern China. Maize yield was sensitive to VPD in more counties than other crops. Soybean was the most sensitive and rice was the least sensitive to VPD among the major crops. In the past three decades, due to the rising trend in VPD, wheat, maize, and soybean yields declined by more than 10.0% in parts of northeastern China and the North China Plain, while rice yields were little affected. For China as a whole, the trend in VPD during 1980-2008 increased rice yields by 1.32%, but reduced wheat, maize, and soybean yields by 6.02%, 3.19%, and 7.07%, respectively. Maize and soybean in the arid and semi-arid regions in northern China were more sensitive to the increase in VPD. These findings highlight that climate change can affect crop growth and yield through increasing VPD, and water-saving technologies and agronomic management need to be strongly encouraged to adapt to ongoing climate change.

  9. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    Science.gov (United States)

    Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.

    2013-06-01

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called "interphase" between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC-TiC)n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC-TiC)n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  10. Vapor pressures and activity coefficients of binary mixtures of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with acetonitrile and tetrahydrofuran

    International Nuclear Information System (INIS)

    Safarov, Javid; Geppert-Rybczyńska, Monika; Hassel, Egon; Heintz, Andreas

    2012-01-01

    Highlights: ► A new apparatus for the determination of VLE is presented. ► The first vapor pressures for binary mixtures containing aprotic solvents in IL are reported. ► Calculated activity coefficients and osmotic coefficients reveal a strong non-ideal behavior. ► A more detailed study of the highly diluted IL concentration range is necessary to test the Debye–Hückel law. - Abstract: A new apparatus for the determination of VLE has been constructed which works for absolute pressure measurements as well as for measuring differential pressures. The first results obtained are (vapor + liquid) equilibria (VLE) of binary mixtures containing acetonitrile or tetrahydrofuran and the ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIm][NTf2] by using the absolute pressures method. VLE measurements were carried out over the whole concentration range at four different temperatures between 293.15 K and 313.15 K. Activity coefficients (γ 1 ) of the solvents in [EMIm][NTf2] and their osmotic coefficients (φ 1 ) have been determined from the VLE data.

  11. The effect of carrier gas flow rate and source cell temperature on low pressure organic vapor phase deposition simulation by direct simulation Monte Carlo method

    Science.gov (United States)

    Wada, Takao; Ueda, Noriaki

    2013-04-01

    The process of low pressure organic vapor phase deposition (LP-OVPD) controls the growth of amorphous organic thin films, where the source gases (Alq3 molecule, etc.) are introduced into a hot wall reactor via an injection barrel using an inert carrier gas (N2 molecule). It is possible to control well the following substrate properties such as dopant concentration, deposition rate, and thickness uniformity of the thin film. In this paper, we present LP-OVPD simulation results using direct simulation Monte Carlo-Neutrals (Particle-PLUS neutral module) which is commercial software adopting direct simulation Monte Carlo method. By estimating properly the evaporation rate with experimental vaporization enthalpies, the calculated deposition rates on the substrate agree well with the experimental results that depend on carrier gas flow rate and source cell temperature.

  12. Vapor Phase Growth of High-Quality Bi-Te Compounds Using Elemental Bi and Te Sources: A Comparison Between High Vacuum and Atmospheric Pressure

    Science.gov (United States)

    Concepción, O.; Escobosa, A.; de Melo, O.

    2018-03-01

    Bismuth telluride (Bi2Te3), traditionally used in the industry as thermoelectric material, has deserved much attention recently due to its properties as a topological insulator, a kind of material that might have relevant applications in spintronics or quantum computing, among other innovative uses. The preparation of high-quality material has become a very important technological task. Here, we compare the preparation of Bi2Te3 by physical vapor transport from the evaporation of elemental Bi and Te sources, under either low pressure or atmospheric pressure. The layers were characterized by different techniques to evaluate its structural properties. As a result, it is concluded that, as a consequence of the different transport regimes, films grown at atmospheric pressure present better crystal quality.

  13. Investigation of Boron Thermal Diffusion from Atmospheric Pressure Chemical Vapor Deposited Boron Silicate Glass for N-Type Solar Cell Process Application

    Directory of Open Access Journals (Sweden)

    Ikuo Kurachi

    2016-01-01

    Full Text Available An atmospheric pressure chemical vapor deposition (AP-CVD system has been newly developed for boron silicate glass (BSG film deposition dedicating to solar cell manufacturing. Using the system, thermal boron diffusion from the BSG film is investigated and confirmed in terms of process stability for surface property before BSG deposition and BSG thickness. No degradation in carrier lifetime is also confirmed. A boron diffusion simulator has been newly developed and demonstrated for optimization of this process. Then, the boron thermal diffusion from AP-CVD BSG is considered to be the suitable method for N-type silicon solar cell manufacturing.

  14. Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles?

    Science.gov (United States)

    Yui, Hiroharu; Banno, Motohiro

    2018-01-01

    In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

  15. Effect of Al_2O_3 Nanoparticles Additives on the Density, Saturated Vapor Pressure, Surface Tension and Viscosity of Isopropyl Alcohol

    Science.gov (United States)

    Zhelezny, Vitaly; Geller, Vladimir; Semenyuk, Yury; Nikulin, Artem; Lukianov, Nikolai; Lozovsky, Taras; Shymchuk, Mykola

    2018-03-01

    This paper presents results of an experimental study of the density, saturated vapor pressure, surface tension and viscosity of Al_2O_3 nanoparticle colloidal solutions in isopropyl alcohol. Studies of the thermophysical properties of nanofluids were performed at various temperatures and concentrations of Al_2O_3 nanoparticles. The paper gives considerable attention to a turbidimetric analysis of the stability of nanofluid samples. Samples of nanofluids remained stable over the range of parameters of the experiments, ensuring the reliability of the thermophysical property data for the Al_2O_3 nanoparticle colloidal solutions in isopropyl alcohol. The studies show that the addition of Al_2O_3 nanoparticles leads to an increase of the density, saturated vapor pressure and viscosity, as well as a decrease for the surface tension of isopropyl alcohol. The information reported in this paper on the various thermophysical properties for the isopropyl alcohol/Al_2O_3 nanoparticle model system is useful for the development of thermodynamically consistent models for predicting properties of nanofluids and correct modeling of the heat exchange processes.

  16. 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

  17. Radiative characteristics and kinetics of processes in low-pressure gas-discharge lamps based on a mixture of helium and iodine vapors

    Science.gov (United States)

    Shuaibov, A. K.; Gomoki, Z. T.; Kalyuzhnaya, A. G.; Shchedrin, A. I.

    2010-11-01

    The UV radiation of glow- and capacitive-discharge lamps based on mixtures of inert gases with iodine vapors are optimized in the spectral range of 175-360 nm, in which working helium-iodine mixtures of different compositions are used. The most intense spectral lines in the bactericidal region of the spectrum were the atomic lines of iodine (183.0, 206.2 nm), and in the region of 320-360 nm, emission of the spectral band of an iodine molecule prevailed with a maximum at λ = 342 nm. For a capacitive lamp with a casing opaque in the spectral range λ iodine molecule with a maximum at 342 nm. The emission brightness of this lamp is optimized in iodine molecule transitions depending on the partial helium pressure. We present the results of simulating the kinetics of processes in a glow-discharge plasma in mixtures of He, Xe, and iodine vapors. We establish the dependence of the main part of the emission intensity of the 206.2 nm spectral line of an iodine atom and the 342 nm band of an iodine molecule on the helium pressure in a glow-discharge lamp operating on a He-I2 mixture.

  18. Thermoeconomic analysis of an integrated multi-effect desalination thermal vapor compression (MED-TVC) system with a trigeneration system using triple-pressure HRSG

    Science.gov (United States)

    Ghaebi, Hadi; Abbaspour, Ghader

    2017-11-01

    In this research, thermoeconomic analysis of a multi-effect desalination thermal vapor compression (MED-TVC) system integrated with a trigeneration system with a gas turbine prime mover is carried out. The integrated system comprises of a compressor, a combustion chamber, a gas turbine, a triple-pressure (low, medium and high pressures) heat recovery steam generator (HRSG) system, an absorption chiller cycle (ACC), and a multi-effect desalination (MED) system. Low pressure steam produced in the HRSG is used to drive absorption chiller cycle, medium pressure is used in desalination system and high pressure superheated steam is used for heating purposes. For thermodynamic and thermoeconomic analysis of the proposed integrated system, Engineering Equation Solver (EES) is used by employing mass, energy, exergy, and cost balance equations for each component of system. The results of the modeling showed that with the new design, the exergy efficiency in the base design will increase to 57.5%. In addition, thermoeconomic analysis revealed that the net power, heating, fresh water and cooling have the highest production cost, respectively.

  19. Thermoeconomic analysis of an integrated multi-effect desalination thermal vapor compression (MED-TVC) system with a trigeneration system using triple-pressure HRSG

    Science.gov (United States)

    Ghaebi, Hadi; Abbaspour, Ghader

    2018-05-01

    In this research, thermoeconomic analysis of a multi-effect desalination thermal vapor compression (MED-TVC) system integrated with a trigeneration system with a gas turbine prime mover is carried out. The integrated system comprises of a compressor, a combustion chamber, a gas turbine, a triple-pressure (low, medium and high pressures) heat recovery steam generator (HRSG) system, an absorption chiller cycle (ACC), and a multi-effect desalination (MED) system. Low pressure steam produced in the HRSG is used to drive absorption chiller cycle, medium pressure is used in desalination system and high pressure superheated steam is used for heating purposes. For thermodynamic and thermoeconomic analysis of the proposed integrated system, Engineering Equation Solver (EES) is used by employing mass, energy, exergy, and cost balance equations for each component of system. The results of the modeling showed that with the new design, the exergy efficiency in the base design will increase to 57.5%. In addition, thermoeconomic analysis revealed that the net power, heating, fresh water and cooling have the highest production cost, respectively.

  20. Impact of right atrial pressure on decision-making using fractional flow reserve (FFR) in elective percutaneous intervention.

    Science.gov (United States)

    Layland, Jamie; Wilson, Andrew M; Whitbourn, Robert J; Burns, Andrew T; Somaratne, Jithendra; Leitl, George; Macisaac, Andrew I

    2013-08-10

    We undertook a prospective study to assess the impact of routine incorporation of right atrial pressure into the calculation of FFR in a real world elective PCI cohort. 42 patients with stenoses in 2 separate epicardial vessels at coronary angiography were studied. Using a temperature and pressure sensing guidewire (TPSG) FFR and FFRRAP were performed in the target vessel pre and post PCI and in a non-target vessel. FFR was defined as Pd/Pa, FFRRAP as Pd-Pv/Pa-Pv where Pv was right atrial pressure and Pd/Pa were the hyperemic distal and proximal arterial pressures respectively. Mean RAP was 9.1 ± 0.7 mmHg. Mean FFR was significantly lower when RAP was included in the calculation (FFRRAP 0.77 ± 0.19 vs. FFR 0.80 ± 0.16, pcalculation of FFR resulted in a significant difference in the FFR value (FFR Pre-PCI 0.69 ± 0.02 vs. FFRRAP Pre-PCI 0.63 ± 0.03, pcalculate FFR prior to PCI, an additional 9 patients would have been re-categorised to an FFR ≤ 0.8. Following PCI, mean FFR was lower when RAP was incorporated (Post PCI FFRRAP 0.93±0.05 vs. Post PCI FFR 0.95 ± 0.06, pcalculation of FFR significantly alters FFR values and may potentially reclassify lesions below ischaemic thresholds. Crown Copyright © 2012. Published by Elsevier Ireland Ltd. All rights reserved.

  1. Obtenção da massa molar de asfaltenos através de osmometria de pressão de vapor Determination of the molar mass of asphaltenes using vapor pressure osmometry

    Directory of Open Access Journals (Sweden)

    Lyzette G. M. de Moura

    2009-01-01

    Full Text Available A massa molar é uma propriedade essencial na caracterização de asfaltenos e um dos principais parâmetros de entrada nos modelos para a predição da precipitação. Na literatura são relatadas massas molares entre 1000 e 10000 g.mol-1 para os asfaltenos, variando em função da técnica, natureza do petróleo, tipo de solvente e temperatura. Neste trabalho foi determinada a massa molar média numérica para dois asfaltenos em tolueno, o C7I (insolúveis em heptano e o C5I (insolúveis em pentano através da osmometria de pressão de vapor. Os dados experimentais foram avaliados levando em consideração efeitos da agregação dos asfaltenos em solução e sua maior dispersão em baixas concentrações. Foram feitos ainda ajustes matemáticos respeitando a tendência das curvas para diluições infinitas buscando produzir melhores resultados no valor da massa molar. Os valores obtidos foram comparados com os métodos convencionais aplicados à análise da osmometria de pressão de vapor, e situaram-se entre 3200 e 5200 g.mol-1 para o asfaltenos C5I e entre 4100 e 5400 g.mol-1 para o C7I.Molar mass is an essential property for the characterization of asphaltenes and one of the main input parameters in the models for the prediction of the precipitation. In the literature molar masses between 1,000 and 10,000 g.mol-1 for the asphaltenes are quoted, depending on the technique, petroleum origin, solvent nature and temperature. In this work the numerical average molar mass for two asphaltenes in toluene, the C7I (insoluble in heptane and the C5I (insoluble in pentane, was determined by vapor pressure osmometry. The experimental data were evaluated taking into account effects of asphaltenes aggregation in solution and its larger dispersion at low concentrations. Mathematical fittings were also made to comply with the curve bias for infinite dilutions, which was aimed at finding more accurate values for the molar mass. The results found were

  2. Prediciton of high-pressure vapor liquid equilibrium of six binary systems, carbon dioxide with six esters, using an artificial neural network model

    Directory of Open Access Journals (Sweden)

    C. Si-Moussa

    2008-03-01

    Full Text Available Artificial neural networks are applied to high-pressure vapor liquid equilibrium (VLE related literature data to develop and validate a model capable of predicting VLE of six CO2-ester binaries (CO2-ethyl caprate, CO2-ethyl caproate, CO2-ethyl caprylate, CO2-diethyl carbonate, CO2-ethyl butyrate and CO2-isopropyl acetate. A feed forward, back propagation network is used with one hidden layer. The model has five inputs (two intensive state variables and three pure ester properties and two outputs (two intensive state variables.The network is systematically trained with 112 data points in the temperature and pressure ranges (308.2-328.2 K, (1.665-9.218 MPa respectively and is validated with 56 data points in the temperature range (308.2-328.2 K. Different combinations of network architecture and training algorithms are studied. The training and validation strategy is focused on the use of a validation agreement vector, determined from linear regression analysis of the plots of the predicted versus experimental outputs, as an indication of the predictive ability of the neural network model. Statistical analyses of the predictability of the optimised neural network model show excellent agreement with experimental data (a coefficient of correlation equal to 0.9995 and 0.9886, and a root mean square error equal to 0.0595 and 0.00032 for the predicted equilibrium pressure and CO2 vapor phase composition respectively. Furthermore, the comparison in terms of average absolute relative deviation between the predicted results for each binary for the whole temperature range and literature results predicted by some cubic equation of state with various mixing rules and excess Gibbs energy models shows that the artificial neural network model gives far better results.

  3. 46 CFR 154.1836 - Vapor venting as a means of cargo tank pressure and temperature control.

    Science.gov (United States)

    2010-10-01

    ... cargo pressure and temperature control system under §§ 154.701 through 154.709 is operating and that venting of cargo is unnecessary to maintain cargo temperature and pressure control, except under emergency... temperature control. 154.1836 Section 154.1836 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY...

  4. Extraction of Kinetic Parameters for the Chemical Vapor Deposition of Polycrystalline Silicon at Medium and Low Pressures

    NARCIS (Netherlands)

    Holleman, J.; Verweij, J.F.; Verweij, Jan F.

    1993-01-01

    The deposition of silicon (Si) from silane (SiH4) was studied in the silane pressure range from 0.5 to 100 Pa (0.005 to1 mbar) and total pressure range from 10 to 1000 Pa using N2 or He as carrier gases. The two reaction paths, namely,heterogeneous and homogeneous decomposition could be separated by

  5. Vapor Intrusion

    Science.gov (United States)

    Vapor intrusion occurs when there is a migration of volatile chemicals from contaminated groundwater or soil into an overlying building. Volatile chemicals can emit vapors that may migrate through subsurface soils and into indoor air spaces.

  6. 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)

  7. 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...... fully strained after 30 min anneal in N-2 at 500 degrees C.; Ge-Sn interdiffusion is seen at 500 degrees C but not at lower temperature. B is 100% active in the in-situ GeSn:B layers up to a concentration of 1.7 x 10(19) cm(-3). GeSn:B provides slightly lower Hall hole mobility values than in pure p......-type Ge especially for low B concentrations. (C) 2011 American Institute of Physics [doi.10.1063/1.3645620]...

  8. High-throughput walkthrough detection portal for counter terrorism: detection of triacetone triperoxide (TATP) vapor by atmospheric-pressure chemical ionization ion trap mass spectrometry.

    Science.gov (United States)

    Takada, Yasuaki; Nagano, Hisashi; Suzuki, Yasutaka; Sugiyama, Masuyuki; Nakajima, Eri; Hashimoto, Yuichiro; Sakairi, Minoru

    2011-09-15

    With the aim of improving security, a high-throughput portal system for detecting triacetone triperoxide (TATP) vapor emitted from passengers and luggage was developed. The portal system consists of a push-pull air sampler, an atmospheric-pressure chemical ionization (APCI) ion source, and an explosives detector based on mass spectrometry. To improve the sensitivity of the explosives detector, a novel linear ion trap mass spectrometer with wire electrodes (wire-LIT) is installed in the portal system. TATP signals were clearly obtained 2 s after the subject under detection passed through the portal system. Preliminary results on sensitivity and throughput show that the portal system is a useful tool for preventing the use of TATP-based improvised explosive devices by screening persons in places where many people are coming and going. Copyright © 2011 John Wiley & Sons, Ltd.

  9. 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.

  10. THE STABILITY OF VAPOR CONDENSATION EQUILIBRIUM

    OpenAIRE

    SHIMIN ZHANG

    2005-01-01

    The system must get across an energy peak of unstable equilibrium during the condensation of pure vapor; as the supersaturated extent of vapor increases and the temperature decreases, the energy peak shortens and vapor condensation becomes easier. The system must get across an energy peak of unstable equilibrium first, and then get into an energy valley of stable equilibrium during the condensation of impure vapor; as the partial pressure of vapor decreases, the energy peak becomes taller, th...

  11. Evaluation of final vapor pressures in the loss of flow accident in an irradiation device of a pool reactor core

    International Nuclear Information System (INIS)

    Verri, A.

    1987-01-01

    The reliability feature, are described for a device containing samples, at a temperatures of 300 grade centigrades, in a reactor core for a long time. After an examination of the maximum accident event, the maximum vapour pressure originated by the inlet of reactor cooling water into the experimental device, is evaluated

  12. High-pressure vapor-liquid equilibria of systems containing ethylene glycol, water and methane - Experimental measurements and modeling

    DEFF Research Database (Denmark)

    Folas, Georgios; Berg, Ole J.; Solbraa, Even

    2007-01-01

    This work presents new experimental phase equilibrium measurements of the binary MEG-methane and the ternary MEG-water-methane system at low temperatures and high pressures which are of interest to applications related to natural gas processing. Emphasis is given to MEG and water solubility...

  13. Atmospheric pressure plasma chemical vapor deposition reactor for 100 mm wafers, optimized for minimum contamination at low gas flow rates

    International Nuclear Information System (INIS)

    Anand, Venu; Shivashankar, S. A.; Nair, Aswathi R.; Mohan Rao, G.

    2015-01-01

    Gas discharge plasmas used for thinfilm deposition by plasma-enhanced chemical vapor deposition (PECVD) must be devoid of contaminants, like dust or active species which disturb the intended chemical reaction. In atmospheric pressure plasma systems employing an inert gas, the main source of such contamination is the residual air inside the system. To enable the construction of an atmospheric pressure plasma (APP) system with minimal contamination, we have carried out fluid dynamic simulation of the APP chamber into which an inert gas is injected at different mass flow rates. On the basis of the simulation results, we have designed and built a simple, scaled APP system, which is capable of holding a 100 mm substrate wafer, so that the presence of air (contamination) in the APP chamber is minimized with as low a flow rate of argon as possible. This is examined systematically by examining optical emission from the plasma as a function of inert gas flow rate. It is found that optical emission from the plasma shows the presence of atmospheric air, if the inlet argon flow rate is lowered below 300 sccm. That there is minimal contamination of the APP reactor built here, was verified by conducting an atmospheric pressure PECVD process under acetylene flow, combined with argon flow at 100 sccm and 500 sccm. The deposition of a polymer coating is confirmed by infrared spectroscopy. X-ray photoelectron spectroscopy shows that the polymer coating contains only 5% of oxygen, which is comparable to the oxygen content in polymer deposits obtained in low-pressure PECVD systems

  14. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

    Science.gov (United States)

    Tellinghuisen, Joel

    2010-01-01

    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  15. EVAPORATION: a new vapor pressure estimation method for organic molecules including non-additivity and intramolecular interactions

    Science.gov (United States)

    Compernolle, S.; Ceulemans, K.; Müller, J.-F.

    2011-04-01

    We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects), a method to predict vapour pressure p0 of organic molecules needing only molecular structure as input. The method is applicable to zero-, mono- and polyfunctional molecules. A simple formula to describe log10p0(T) is employed, that takes into account both a wide temperature dependence and the non-additivity of functional groups. In order to match the recent data on functionalised diacids an empirical modification to the method was introduced. Contributions due to carbon skeleton, functional groups, and intramolecular interaction between groups are included. Molecules typically originating from oxidation of biogenic molecules are within the scope of this method: carbonyls, alcohols, ethers, esters, nitrates, acids, peroxides, hydroperoxides, peroxy acyl nitrates and peracids. Therefore the method is especially suited to describe compounds forming secondary organic aerosol (SOA).

  16. Synthesis of Ordered Mesoporous Phenanthrenequinone-Carbon via π-π Interaction-Dependent Vapor Pressure for Rechargeable Batteries

    OpenAIRE

    Kwon, Mi-Sook; Choi, Aram; Park, Yuwon; Cheon, Jae Yeong; Kang, Hyojin; Jo, Yong Nam; Kim, Young-Jun; Hong, Sung You; Joo, Sang Hoon; Yang, Changduk; Lee, Kyu Tae

    2014-01-01

    The π-π interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place. The confinement of the phenanthrenequinone in the mesoporous carbon mitigates the diffusion of the dissolved phenanthrenequinone out of the mesoporous car...

  17. Synthesis of Ordered Mesoporous Phenanthrenequinone-Carbon via π-π Interaction-Dependent Vapor Pressure for Rechargeable Batteries

    Science.gov (United States)

    Kwon, Mi-Sook; Choi, Aram; Park, Yuwon; Cheon, Jae Yeong; Kang, Hyojin; Jo, Yong Nam; Kim, Young-Jun; Hong, Sung You; Joo, Sang Hoon; Yang, Changduk; Lee, Kyu Tae

    2014-12-01

    The π-π interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place. The confinement of the phenanthrenequinone in the mesoporous carbon mitigates the diffusion of the dissolved phenanthrenequinone out of the mesoporous carbon, and improves cycling performance.

  18. High-pressure vapor-phase hydrodeoxygenation of lignin-derived oxygenates to hydrocarbons by a PtMo bimetallic catalyst: Product selectivity, reaction pathway, and structural characterization

    Energy Technology Data Exchange (ETDEWEB)

    Yohe, Sara L.; Choudhari, Harshavardhan J.; Mehta, Dhairya D.; Dietrich, Paul J.; Detwiler, Michael D.; Akatay, Cem M.; Stach, Eric A.; Miller, Jeffrey T.; Delgass, W. Nicholas; Agrawal, Rakesh; Ribeiro, Fabio H.

    2016-12-01

    High-pressure, vapor-phase, hydrodeoxygenation (HDO) reactions of dihydroeugenol (2-methoxy-4-propylphenol), as well as other phenolic, lignin-derived compounds, were investigated over a bimetallic platinum and molybdenum catalyst supported on multi-walled carbon nanotubes (5%Pt2.5%Mo/MWCNT). Hydrocarbons were obtained in 100% yield from dihydroeugenol, including 98% yield of the hydrocarbon propylcyclohexane. The final hydrocarbon distribution was shown to be a strong function of hydrogen partial pressure. Kinetic analysis showed three main dihydroeugenol reaction pathways: HDO, hydrogenation, and alkylation. The major pathway occurred via Pt catalyzed hydrogenation of the aromatic ring and methoxy group cleavage to form 4-propylcyclohexanol, then Mo catalyzed removal of the hydroxyl group by dehydration to form propylcyclohexene, followed by hydrogenation of propylcyclohexene on either the Pt or Mo to form the propylcyclohexane. Transalkylation by the methoxy group occurred as a minor side reaction. Catalyst characterization techniques including chemisorption, scanning transmission electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize the catalyst structure. Catalyst components identified were Pt particles, bimetallic PtMo particles, a Mo carbide-like phase, and Mo oxide phases.

  19. The effect of blood pressure on non-invasive fractional flow reserve derived from coronary computed tomography angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kurata, Akira [Ehime University Graduate School of Medicine, Department of Radiology, Toon, Ehime (Japan); Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Coenen, Adriaan; Lubbers, Marisa M.; Nieman, Koen [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands); Erasmus University Medical Center, Departmenet of Cardiology, Rotterdam (Netherlands); Kido, Teruhito; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon, Ehime (Japan); Kido, Tomoyuki [Matsuyama Saiseikai Hospital, Department of Radiology, Matsuyama, Ehime (Japan); Yamashita, Natsumi [Clinical Research Center, National Hospital Organization Shikoku Cancer Center, Division of Clinical Biostatistics, Section of Cancer Prevention and Epidemiology, Matsuyama, Ehime (Japan); Watanabe, Kouki [Matsuyama Saiseikai Hospital, Department of Cardiology, Matsuyama, Ehime (Japan); Krestin, Gabriel P. [Erasmus University Medical Center, Department of Radiology, Rotterdam (Netherlands)

    2017-04-15

    The aim of this study is to assess the effect of blood pressure (BP) on coronary computed tomography angiography (CTA) derived computational fractional flow reserve (CTA-FFR). Twenty-one patients who underwent coronary CTA and invasive FFR were retrospectively identified. Ischemia was defined as invasive FFR ≤0.80. Using a work-in-progress computational fluid dynamics algorithm, CTA-FFR was computed with BP measured before CTA, and simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg respectively. Correlation between CTA-FFR and invasive FFR was assessed using Pearson test. The repeated measuring test was used for multiple comparisons of CTA-FFR values by simulated BP inputs. Twenty-nine vessels (14 with invasive FFR ≤0.80) were assessed. The average CTA-FFR for measured BP (134 ± 20/73 ± 12 mmHg) was 0.77 ± 0.12. Correlation between CTA-FFR by measured BP and invasive FFR was good (r = 0.735, P < 0.001). For simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg, the CTA-FFR increased: 0.69 ± 0.13, 0.73 ± 0.12, 0.75 ± 0.12, 0.77 ± 0.11, 0.79 ± 0.11, and 0.81 ± 0.10 respectively (P < 0.05). Measurement of the BP just before CTA is preferred for accurate CTA-FFR simulation. BP variations in the common range slightly affect CTA-FFR. However, inaccurate BP assumptions differing from the patient-specific BP could cause misinterpretation of borderline significant lesions. (orig.)

  20. The effect of blood pressure on non-invasive fractional flow reserve derived from coronary computed tomography angiography

    International Nuclear Information System (INIS)

    Kurata, Akira; Coenen, Adriaan; Lubbers, Marisa M.; Nieman, Koen; Kido, Teruhito; Mochizuki, Teruhito; Kido, Tomoyuki; Yamashita, Natsumi; Watanabe, Kouki; Krestin, Gabriel P.

    2017-01-01

    The aim of this study is to assess the effect of blood pressure (BP) on coronary computed tomography angiography (CTA) derived computational fractional flow reserve (CTA-FFR). Twenty-one patients who underwent coronary CTA and invasive FFR were retrospectively identified. Ischemia was defined as invasive FFR ≤0.80. Using a work-in-progress computational fluid dynamics algorithm, CTA-FFR was computed with BP measured before CTA, and simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg respectively. Correlation between CTA-FFR and invasive FFR was assessed using Pearson test. The repeated measuring test was used for multiple comparisons of CTA-FFR values by simulated BP inputs. Twenty-nine vessels (14 with invasive FFR ≤0.80) were assessed. The average CTA-FFR for measured BP (134 ± 20/73 ± 12 mmHg) was 0.77 ± 0.12. Correlation between CTA-FFR by measured BP and invasive FFR was good (r = 0.735, P < 0.001). For simulated BPs of 60/50, 90/60, 110/70, 130/80, 150/90, and 180/100 mmHg, the CTA-FFR increased: 0.69 ± 0.13, 0.73 ± 0.12, 0.75 ± 0.12, 0.77 ± 0.11, 0.79 ± 0.11, and 0.81 ± 0.10 respectively (P < 0.05). Measurement of the BP just before CTA is preferred for accurate CTA-FFR simulation. BP variations in the common range slightly affect CTA-FFR. However, inaccurate BP assumptions differing from the patient-specific BP could cause misinterpretation of borderline significant lesions. (orig.)

  1. Thermophysical properties of biodiesel and related systems: Low-pressure vapor + liquid equilibrium of methyl/ethyl soybean biodiesel

    International Nuclear Information System (INIS)

    Veneral, Josamaique G.; Junior, Dirceu L.R.; Mazutti, Marcio A.; Voll, Fernando A.P.; Cardozo-Filho, Lúcio; Corazza, Marcos L.; Silva, Edson A.; Oliveira, J. Vladimir

    2013-01-01

    Highlights: • Boiling point temperatures for soybean FAME and FAEE measured in the pressure range of (6.7 to 66.7) kPa. • Investigated systems presented a non-ideal behavior, with positive deviations from Raoult’s law. • Experimental data satisfactorily represented by the UNIQUAC model. -- Abstract: In this work, experimental boiling point temperatures for pseudo-binaries (methyl/ethyl biodiesel + methanol/ethanol) and pseudo-ternaries (methyl/ethyl biodiesel + methanol/ethanol + glycerol/water) systems were measured at several pressures ranging from (6.7 to 66.7) kPa using an Othmer-type ebulliometer. The systems investigated show a non-ideal behavior, with positive deviations from Raoult’s law. It was observed that the addition of up to 10 wt% of alcohol (methanol or ethanol) led to a significant decrease in the boiling point temperature of the systems. The UNIQUAC model was successfully used to represent the experimental results, with an overall average deviation between experimental and calculated boiling temperature values of 0.004%

  2. Water adsorbate phases on ZnO and impact of vapor pressure on the equilibrium shape of nanoparticles

    Science.gov (United States)

    Kenmoe, Stephane; Biedermann, P. Ulrich

    2018-02-01

    ZnO nanoparticles are used as catalysts and have potential applications in gas-sensing and solar energy conversion. A fundamental understanding of the exposed crystal facets, their surface chemistry, and stability as a function of environmental conditions is essential for rational design and improvement of synthesis and properties. We study the stability of water adsorbate phases on the non-polar low-index (10 1 ¯ 0 ) and (11 2 ¯ 0 ) surfaces from low coverage to multilayers using ab initio thermodynamics. We show that phonon contributions and the entropies due to a 2D lattice gas at low coverage and multiple adsorbate configurations at higher coverage have an important impact on the stability range of water adsorbate phases in the (T,p) phase diagram. Based on this insight, we compute and analyze the possible growth mode of water films for pressures ranging from UHV via ambient conditions to high pressures and the impact of water adsorption on the equilibrium shape of nanoparticles in a humid environment. A 2D variant of the Wulff construction shows that the (10 1 ¯ 0 ) and (11 2 ¯ 0 ) surfaces coexist on 12-faceted prismatic ZnO nanoparticles in dry conditions, while in humid environment, the (10 1 ¯ 0 ) surface is selectively stabilized by water adsorption resulting in hexagonal prisms.

  3. Vascular flow reserve as a link between long-term blood pressure level and physical performance capacity in mammals

    DEFF Research Database (Denmark)

    Poulsen, Christian B; Damkjær, Mads; Hald, Bjørn O

    2016-01-01

    Mean arterial pressure (MAP) is surprisingly similar across different species of mammals, and it is, in general, not known which factors determine the arterial pressure level. Mammals often have a pronounced capacity for sustained physical performance. This capacity depends on the vasculature...... provides a conceptual explanation of why high performing animals tend to have a high MAP....

  4. Long-term stable water vapor permeation barrier properties of SiN/SiCN/SiN nanolaminated multilayers grown by plasma-enhanced chemical vapor deposition at extremely low pressures

    International Nuclear Information System (INIS)

    Choi, Bum Ho; Lee, Jong Ho

    2014-01-01

    We investigated the water vapor permeation barrier properties of 30-nm-thick SiN/SiCN/SiN nanolaminated multilayer structures grown by plasma enhanced chemical vapor deposition at 7 mTorr. The derived water vapor transmission rate was 1.12 × 10 −6 g/(m 2 day) at 85 °C and 85% relative humidity, and this value was maintained up to 15 000 h of aging time. The X-ray diffraction patterns revealed that the nanolaminated film was composed of an amorphous phase. A mixed phase was observed upon performing high resolution transmission electron microscope analysis, which indicated that a thermodynamically stable structure was formed. It was revealed amorphous SiN/SiCN/SiN multilayer structures that are free from intermixed interface defects effectively block water vapor permeation into active layer

  5. Directed vapor deposition

    Science.gov (United States)

    Groves, James Frederick

    This dissertation describes the invention, design, construction, experimental evaluation and modeling of a new physical vapor deposition technique (U.S. Patent #5,534,314) for high rate, efficient deposition of refractory elements, alloys, and compounds onto flat or curved surfaces. The new Directed Vapor Deposition (DVD) technique examined in this dissertation was distinct from previous physical vapor deposition techniques because it used low vacuum electron beam (e-beam) evaporation in combination with a carrier gas stream to transport and vapor spray deposit metals, ceramics, and semiconducting materials. Because of the system's unique approach to vapor phase materials processing, detailed analyses of critical concepts (e.g. the e-beam accelerating voltage and power required for evaporation, the vacuum pumping capacity necessary to generate specific gas flow velocities exiting a nozzle) were used to reduce to practice a functioning materials synthesis tool. After construction, the ability to create low contamination films of pure metals, semi-conducting materials, and compounds via this new method was demonstrated, and oxide deposition using an oxygen-doped gas stream in combination with a pure metal evaporant source was shown to be feasible. DVD vapor transport characteristics were experimentally investigated with deposition chamber pressure, carrier gas type, and e-beam power being identified as major processing parameters which affected vapor atom trajectories. The low vacuum carrier gas streams employed in DVD showed a dramatic ability to focus the vapor stream during transport to the substrate and thereby enhance material deposition rates and efficiencies significantly under certain process conditions. Conditions for maximum deposition efficiency onto flat substrates and continuous fibers were experimentally identified by varying chamber pressure, carrier gas velocity (Mach number), and e-beam power. Deposition efficiencies peaked at about 0.5 Torr when

  6. Effect of growth conditions on the Al composition and optical properties of Al x Ga 1−x N layers grown by atmospheric-pressure metal organic vapor phase epitaxy

    KAUST Repository

    Soltani, S.

    2017-02-17

    The effect of growth conditions on the Al composition and optical properties of AlxGa1-xN layers grown by atmospheric-pressure metal organic vapor phase epitaxy is investigated. The Al content of the samples is varied between 3.0% and 9.3% by changing the gas flow rate of either trimethylaluminum (TMA) or trimethylgallium (TMG) while other growth parameters are kept constant. The optical properties of the AlxGa1-xN layers are studied by photoreflectance and time-resolved photoluminescence (TR-PL) spectroscopies. A degeneration in the material quality of the samples is revealed when the Al content is increased by increasing the TMA flow rate. When the TMG flow rate is decreased with a fixed TMA flow rate, the Al content of the AlxGa1-xN layers is increased and, furthermore, an improvement in the optical properties corresponding with an increase in the PL decay time is observed. (C) 2017 Elsevier B.V. All rights reserved.

  7. Enhancement and retardation of thermal boron diffusion in silicon from atmospheric pressure chemical vapor deposited boron silicate glass film

    Science.gov (United States)

    Kurachi, Ikuo; Yoshioka, Kentaro

    2014-03-01

    Thermal boron diffusion into silicon from boron silicate glass (BSG) prepared by atmospheric pressure CVD (AP-CVD) has been investigated in terms of the BSG boron concentration dependence on diffusion mechanism for N-type solar cell applications. With thermal diffusion at 950 °C in N2 for 20 min, the sheet resistance of the boron-diffused layer decreases with BSG boron concentration up to approximately 4 × 1021 cm-3 at which a boron-rich layer (BRL) is formed at the surface. However, the resistance increases with BSG boron concentration when the BSG boron concentration is higher than 4 × 1021 cm-3. It is also confirmed that the diffusion depth decreases with increasing BSG boron concentration within this BSG concentration region. To clarify this mechanism, the BSG boron concentration dependence on boron diffusivity has also been studied. From extracted diffusivities, the anomalous diffusion can be explained by silicon interstitials formed owing to kick-out by diffused boron atoms and by silicon interstitial generation-degradation due to BRL formation.

  8. Regulation of Vapor Pressure Deficit by Greenhouse Micro-Fog Systems Improved Growth and Productivity of Tomato via Enhancing Photosynthesis during Summer Season.

    Directory of Open Access Journals (Sweden)

    Dalong Zhang

    Full Text Available The role of a proposed micro-fog system in regulating greenhouse environments and enhancing tomato (Solanum lycopersicum L. productivity during summer season was studied. Experiments were carried out in a multi-span glass greenhouse, which was divided into two identical compartments involving different environments: (1 without environment control and (2 with a micro-fog system operating when the air vapor pressure deficit (VPD of greenhouse was higher than 0.5 KPa. The micro-fog system effectively alleviated heat stress and evaporative demand in the greenhouse during summer season. The physiologically favourable environment maintained by micro-fog treatment significantly enhanced elongation of leaf and stem, which contributed to a substantial elevation of final leaf area and shoot biomass. These improvements in physiological and morphological traits resulted in around 12.3% increase of marketable tomato yield per plant. Relative growth rate (RGR of micro-fog treatment was also significantly higher than control plants, which was mainly determined by the substantial elevation in net assimilation rate (NAR, and to a lesser extent caused by leaf area ratio (LAR. Measurement of leaf gas exchange parameters also demonstrated that micro-fog treatment significantly enhanced leaf photosynthesis capacity. Taken together, manipulation of VPD in greenhouses by micro-fog systems effectively enhanced tomato growth and productivity via improving photosynthesis during summer season.

  9. Liquid-vapor equilibrium of the systems butylmethylimidazolium nitrate-CO2 and hydroxypropylmethylimidazolium nitrate-CO2 at high pressure: influence of water on the phase behavior.

    Science.gov (United States)

    Bermejo, M Dolores; Montero, Marta; Saez, Elisa; Florusse, Louw J; Kotlewska, Aleksandra J; Cocero, M José; van Rantwijk, Fred; Peters, Cor J

    2008-10-30

    Ionic liquids (IL) are receiving increasing attention due to their potential as "green" solvents, especially when used in combination with SC-CO2. In this work liquid-vapor equilibria of binary mixtures of CO2 with two imidazolium-based ionic liquids (IL) with a nitrate anion have been experimentally determined: butylmethylimidazolium nitrate (BMImNO3) and hydroxypropylmethylimidazolium nitrate (HOPMImNO3), using a Cailletet apparatus that operates according to the synthetic method. CO2 concentrations from 5 up to 30 mol % were investigated. It was found that CO2 is substantially less soluble in HOPMImNO3 than in BMImNO3. Since these ILs are very hygroscopic, water easily can be a major contaminant, causing changes in the phase behavior. In case these Ils are to be used in practical applications, for instance, together with CO2 as a medium in supercritical enzymatic reactions, it is very important to have quantitative information on how the water content will affect the phase behavior. This work presents the first systematic study on the influence of water on the solubility of carbon dioxide in hygroscopic ILs. It was observed that the presence of water reduces the absolute solubility of CO2. However, at fixed ratios of CO2/IL, the bubble point pressure remains almost unchanged with increasing water content. In order to explain the experimental results, the densities of aqueous mixtures of both ILs were determined experimentally and the excess molar volumes calculated.

  10. Doping characteristics of Si-doped n-GaN Epilayers grown by low-pressure metal-organic chemical-vapor deposition

    CERN Document Server

    Noh, S K; Park, S E; Lee, I H; Choi, I H; Son, S J; Lim, K Y; Lee, H J

    1998-01-01

    We studied doping behaviors through analysis of the electronic properties of a series of undoped and Si-doped GaN epilayers grown on (0001) sapphire substrates by the low-pressure metal-organic chemical-vapor deposition (LP-MOCVD) technique. The doping efficiency was in the range of 0.4 - 0.8, and an empirical relation expressed as eta = 0.45 log[Si] - 8.1 was obtained. The temperature dependence of carrier concentration showed that the donor activation energy monotonically decreased from 17.6 meV to almost zero as the doping level increased. We suggest that the reduction in the activation energy is related not to autodoped defect centers but to doped Si donors and that the behavior originates from the formation of an impurity band. On the basis of an abrupt change in the compensation ratio from 0.9 to 0.5 by Si-doping, an exceptional difference in the Hall mobility between the undoped and the Si-doped films is explained by a mixed conduction mechanism of electrons and holes.

  11. High intensity interval training (HIIT) improves resting blood pressure, metabolic (MET) capacity and heart rate reserve without compromising cardiac function in sedentary aging men.

    Science.gov (United States)

    Grace, Fergal; Herbert, Peter; Elliott, Adrian D; Richards, Jo; Beaumont, Alexander; Sculthorpe, Nicholas F

    2017-05-13

    This study examined a programme of pre-conditioning exercise with subsequent high intensity interval training (HIIT) on blood pressure, echocardiography, cardiac strain mechanics and maximal metabolic (MET) capacity in sedentary (SED) aging men compared with age matched masters athletes (LEX). Using a STROBE compliant observational design, 39 aging male participants (SED; n=22, aged 62.7±5.2yrs) (LEX; n=17, aged=61.1±5.4yrs) were recruited to a study that necessitated three distinct assessment phases; enrolment (Phase A), following pre-conditioning exercise in SED (Phase B), then following 6weeks of HIIT performed once every five days by both groups before reassessment (Phase C). Hemodynamic, echocardiographic and cardiac strain mechanics were obtained at rest and maximal cardiorespiratory and chronotropic responses were obtained at each measurement phase. The training intervention improved systolic, mean arterial blood pressure, rate pressure product and heart rate reserve (each PHIIT. Echocardiography and cardiac strain measures were unremarkable apart from trivial increase to intra-ventricular septum diastole (IVSd) (PHIIT. A programme of preconditioning exercise with HIIT induces clinically relevant improvements in blood pressure, rate pressure product and encourages recovery of heart rate reserve in SED, while improving maximal MET capacity in both SED and LEX without inducing any pathological cardiovascular remodeling. These data add to the emerging repute of HIIT as a safe and promising exercise prescription to improve cardiovascular function and metabolic capacity in sedentary aging. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. The effects of fire and grazing pressure on the vegetation cover and small mammal populations in the Masai Mara Nature Reserve

    NARCIS (Netherlands)

    Salvatori, V.; Egunyu, F.; Skidmore, A.K.; Leeuw, de J.; Gils, van H.A.M.

    2001-01-01

    An extensive study of vegetation changes as a consequence of fire and grazing pressure and their effect on small mammal populations inside the Maasai Mara National Reserve, Kenya, was carried out during May-June 1997. Comparison of vegetation maps from 1979 and 1998 suggested that vegetation in 46 f

  13. Using transthoracic Doppler echocardiography to diagnose reduced coronary flow velocity reserve in the posterior descending coronary artery in children with elevated right ventricular pressure.

    Science.gov (United States)

    Shimada, Shunsuke; Harada, Kenji; Toyono, Manatomo; Tamura, Masamichi; Takada, Goro

    2007-12-01

    Advances in transthoracic Doppler echocardiography enable noninvasive measurements of coronary flow velocity and coronary flow velocity reserve (CFVR) in the posterior descending coronary artery (PD). To evaluate CFVR in the PD of children with elevated right ventricular (RV) pressure, 19 children with RV pressure overload and 13 age-matched controls with normal RV pressure were studied using transthoracic Doppler echocardiography. Average peak flow velocity (APV) was measured at rest and in hyperemic conditions (intravenous administration of adenosine of 0.16 mg.kg(-1).min(-1)). Compared with controls, the PD CFVR was significantly reduced in the patients with elevated RV pressure (1.87+/-0.42 vs 2.49+/-0.55, pvelocity.

  14. The effect of thermal annealing on the adherence of Al2O3-films deposited by low-pressure, metal-organic, chemical-vapor deposition on AISI 304

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Haanappel, V.A.C.; van de Vendel, D.; van Corbach, H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films, deposited at 280°C by low-pressure, metal-organic, chemical-vapor deposition on stainless steel, type AISI 304, were annealed at 0.17 kPa in a nitrogen atmosphere for 2,4, and 17 hr at 600, 700, and 800°C. The effect of the annealing process on the adhesion of the thin alumina

  15. Halogenated methyl-phenyl ethers (anisoles) in the environment: determination of vapor pressures, aqueous solubilities, Henry's law constants, and gas/water- (Kgw), n-octanol/water- (Kow) and gas/n-octanol (Kgo) partition coefficients.

    Science.gov (United States)

    Pfeifer, O; Lohmann, U; Ballschmiter, K

    2001-11-01

    Halogenated methyl-phenyl ethers (methoxybenzenes, anisoles) are ubiquitous organics in the environment although they are not produced in industrial quantities. Modelling the fate of organic pollutants such as halogenated anisoles requires a knowledge of the fundamental physico-chemical properties of these compounds. The isomer-specific separation and detection of 60 of the 134 possible congeners allowing an environmental fingerprinting are reported in this study. The vapor pressure p0(L) of more than 60 and further physico-chemical properties of 26 available congeners are given. Vapor pressures p0(L), water solubilities S(L)W, and n-octanol/water partition coefficients Kow were determined by capillary HR-GC (High Resolution Gas Chromatography) on a non-polar phase and by RP-HPLC (Reversed Phase High Performance Liquid Chromatography) on a C18 phase with chlorobenzenes as reference standards. From these experimental data the Henry's law constants H, and the gas/water Kgw and gas/n-octanol Kgo partition coefficients were calculated. We found that vapor pressures, water solubilities, and n-octanol/water partition coefficients of the halogenated anisoles are close to those of the chlorobenzenes. A similar environmental fate of both groups can, therefore, be predicted.

  16. Raman study of light-emitting SiN{sub x} films grown on Si by low-pressure chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Komarov, F. [A.N. Sevchenko Institute of Applied Physics Problems, Kurchatov Str. 7, 220045 Minsk (Belarus); Vlasukova, L. [Belarusian State University, Nezavisimosty Ave. 4, 220030 Minsk (Belarus); Parkhomenko, I., E-mail: irinaparkhomen@gmail.com [Belarusian State University, Nezavisimosty Ave. 4, 220030 Minsk (Belarus); Milchanin, O. [A.N. Sevchenko Institute of Applied Physics Problems, Kurchatov Str. 7, 220045 Minsk (Belarus); Mudryi, A. [Scientific and Practical Materials Research Center, National Academy of Sciences of Belarus, P. Brovki Str. 17, 220072 Minsk (Belarus); Togambaeva, A. [Al-Farabi Kazakh National University, Al-Farabiy Ave. 71, 050038 Almaty (Kazakhstan); Korolik, O. [Belarusian State University, Nezavisimosty Ave. 4, 220030 Minsk (Belarus)

    2015-03-31

    Si-rich silicon nitride (SRSN) films were deposited on Si wafers by low pressure chemical vapor deposition (LPCVD) technique and, subsequently, annealed at (800–1200) °C to form Si precipitates. The composition of SiN{sub x} films was measured by Rutherford backscattering spectrometry (RBS). Two sets of samples differed by the amount of excessive Si (Si{sub exc}) in silicon nitride were studied. Evolution of Si nanoclusters from amorphous to crystalline ones during high temperature treatment was examined by Raman scattering (RS) spectroscopy. The amorphous Si clusters were already revealed in as-deposited SiN{sub x} while the annealing results in their crystallization. The crystalline nanoprecipitates are only registered in nitride films after annealing at 1200 °C. A dependence of Raman scattering intensity from the Si wafer on the temperature of annealing of SiN{sub x}/Si structures was revealed. This information was used to explain the phase transformations in SRSNs during high temperature treatments. The peculiarities of photoluminescence (PL) spectra for two sets of Si-rich SiN{sub x} films are explained taking into account the contribution from the quantum confinement effect of Si nanocrystals and from the native defects in silicon nitride matrix, such as N- and K-centers. - Highlights: • The size of Si nanocrystals in Si-rich SiN{sub x} films depends on Si excess content. • Excess Si remains in SiN{sub 0.46} as randomly distributed Si atoms in atomic network. • In SiN{sub 1} films practically all excess Si is aggregated into Si nanoclusters.

  17. Electrochemical performance of LiFePO4 modified by pressure-pulsed chemical vapor infiltration in lithium-ion batteries

    International Nuclear Information System (INIS)

    Li Jianling; Suzuki, Tomohiro; Naga, Kazuhisa; Ohzawa, Yoshimi; Nakajima, Tsuyoshi

    2007-01-01

    Using the pressure-pulsed chemical vapor infiltration (PCVI) technique, pyrolytic carbon (pyrocarbon) films were deposited on the surface of LiFePO 4 particles for cathode material of lithium-ion batteries. The electrochemical performance of the original LiFePO 4 and PCVIed LiFePO 4 materials was evaluated using a three electrodes cell by galvanostatic charging/discharging at 25, 40 and 55 deg. C, respectively. Morphology and structure of LiFePO 4 were analyzed by SEM, XRD and Raman. The resulting carbon contents at 500, 1000, 2000, 3000 and 5000 pulses were 2.7, 4.7, 9.5, 15.1 and 19.4%, respectively and these samples were abbreviated as 500P, 1000P, 2000P, 3000P and 5000P, respectively. All the PCVIed samples exhibited excellent rate performance. The tendency was more and more obvious with the increase of the current densities. The specific capacities of 500P, 1000P and 2000P were maintained at 117, 124 and 132 mAh g -1 , respectively, which were 120.8, 264.7 and 29.47% larger than those of corresponding original LiFePO 4 , respectively, at a 5C rate at 55 deg. C. The EIS measurement showed that electrochemical reaction resistance (R ct ) of PCVIed LiFePO 4 were obviously decreased, indicating a fast kinetics compared to the original LiFePO 4 . The cycle ability of the 2000P sample was tested at 25 deg. C and C/2 rate. The cell was cycled for 150 cycles and no obviously capacity fade was observed. Its specific capacity of 115 mAh g -1 at 150th cycle is 1.7 times higher than that of original LiFePO 4

  18. Atmospheric Pressure Chemical Vapor Deposition of CdTe for High-Efficiency Thin-Film PV Devices; Annual Report, 26 January 1998-25 January 1999

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, P. V. [ITN Energy Systems, Wheat Ridge, Colorado (US); Kee, R.; Wolden, C.; Raja, L.; Kaydanov, V.; Ohno, T.; Collins, R.; Aire, M.; Kestner, J. [Colorado School of Mines, Golden, Colorado (US); Fahrenbruch, A. [ALF, Inc., Stanford, California (US)

    1999-09-30

    ITN's 3-year project, titled ''Atmospheric Pressure Chemical Vapor Deposition (APCVD) of CdTe for High-Efficiency Thin-Film Photovoltaic (PV) Devices,'' has the overall objectives of improving thin-film CdTe PV manufacturing technology and increasing CdTe PV device power conversion efficiency. CdTe deposition by APCVD employs the same reaction chemistry as has been used to deposit 16%-efficient CdTe PV films, i.e., close-spaced sublimation, but employs forced convection rather than diffusion as a mechanism of mass transport. Tasks of the APCVD program center on demonstrating APCVD of CdTe films, discovering fundamental mass-transport parameters, applying established engineering principles to the deposition of CdTe films, and verifying reactor design principles that could be used to design high-throughput, high-yield manufacturing equipment. Additional tasks relate to improved device measurement and characterization procedures that can lead to a more fundamental understanding of CdTe PV device operation, and ultimately, to higher device conversion efficiency and greater stability. Specifically, under the APCVD program, device analysis goes beyond conventional one-dimensional device characterization and analysis toward two-dimension measurements and modeling. Accomplishments of the first year of the APCVD subcontract include: selection of the Stagnant Flow Reactor design concept for the APCVD reactor, development of a detailed reactor design, performance of detailed numerical calculations simulating reactor performance, fabrication and installation of an APCVD reactor, performance of dry runs to verify reactor performance, performance of one-dimensional modeling of CdTe PV device performance, and development of a detailed plan for quantification of grain-boundary effects in polycrystalline CdTe devices.

  19. Early season lightning storms followed by vapor pressure deficit anomalies contributed to an extreme wildfire season near the high latitude treeline in Northwest Canada in 2014

    Science.gov (United States)

    Veraverbeke, S.; Worthy, D. E. J.; Chan, D.; Chan, E.; Wiggins, E. B.; Miller, C. E.; Henderson, J.; Tosca, M. G., Jr.; Randerson, J. T.

    2015-12-01

    Fires are the most important landscape disturbance in the boreal forest. Fire location and extent in boreal ecosystems highly depend on ignitions by lightning and periods of high vapor pressure deficit (VPD) that promote the spread of the fires. We show, using fire perimeter and remotely sensed burned area, that during the 2014 fire season, the Northwest Territories in Canada experienced its most severe fire season since the beginning of the fire perimeter record in 1971. Using a pyrogenic carbon consumption model driven by remotely sensed tree cover and burn severity, and meteorological reanalysis data, we estimate total carbon emissions of 136 (SE = 25) Tg for the entire territory. We also found anomalously large fires relatively close (0-300 km) to the high latitude treeline where sparse black spruce forests transition into tundra, ecosystems that are traditionally less affected by fire disturbance. This area received below-average winter precipitation and experienced an early snow melt in 2014. Using data from the Canadian Lightning Detection Network we show that many of these fires were ignited during lightning storms in May and June, and expanded during periods of anomalously high VPD in June and July. Fires that were ignited before July 1 accounted for approximately 76% of the total annual burned area. We hypothesize that the extent and northward expansion of boreal fires, driven by climatic anomalies in lightning and VPD, may accelerate northward species migration with climate change. We also show, using plume heights retrieved from the Multi-angle Imaging Spectroradiometer (MISR), that maximum plume injection heights in 2014 were on average more than 300 m higher compared to observations from other years. These high injection heights combined with the high latitude location of the fires increase the potential for northward long-range transport of black carbon emissions towards Greenland and other vulnerable components of the northern cryosphere.

  20. GeSn growth kinetics in reduced pressure chemical vapor deposition from Ge2H6 and SnCl4

    Science.gov (United States)

    Aubin, J.; Hartmann, J. M.

    2018-01-01

    We have investigated the low temperature epitaxy of high Sn content GeSn alloys in a 200 mm industrial Reduced Pressure - Chemical Vapor Deposition tool from Applied Materials. Gaseous digermane (Ge2H6) and liquid tin tetrachloride (SnCl4) were used as the Ge and Sn precursors, respectively. The impact of temperature (in the 300-350 °C range), Ge2H6 and SnCl4 mass-flows on the GeSn growth kinetics at 100 Torr has been thoroughly explored. Be it at 300 °C or 325 °C, a linear GeSn growth rate increase together with a sub-linear Sn concentration increase occurred as the SnCl4 mass-flow increased, irrespective of the Ge2H6 mass flow (fixed or varying). The Sn atoms seemed to catalyze H desorption from the surface, resulting in higher GeSn growth rates for high SnCl4 mass-flows (in the 4-21 nm min-1 range). The evolution of the Sn content x with the F (SnCl4) 2 ·/F (Ge2H6) mass-flow ratio was fitted by x2/(1 - x) = n ·F (SnCl4) 2 ·/F (Ge2H6), with n = 0.25 (325 °C) and 0.60 (300 °C). We have otherwise studied the impact of temperature, in the 300-350 °C range, on the GeSn growth kinetics. The GeSn growth rate exponentially increased with the temperature, from 15 up to 32 nm min-1. The associated activation energy was low, i.e. Ea = 10 kcal mol-1. Meanwhile, the Sn content decreased linearly as the growth temperature increased, from 15% at 300 °C down to 6% at 350 °C.

  1. Vapor Pressure of Antimony Triiodide

    Science.gov (United States)

    2017-12-07

    Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law , no person shall be...has little consequence on doping. However, substitutional I on a tellurium (Te) site will serve as a singly ionized donor, and in the case of I on a...Bi or Sb site, will act as a doubly ionized donor. In either of those cases , substitutional I causes n-type conduction. The growth of epitaxial

  2. The relationship between vapour pressure, vaporization enthalpy, and enthalpy of transfer from solution to gas: An extension of the Martin equation

    International Nuclear Information System (INIS)

    Srisaipet, A.; Aryusuk, K.; Lilitchan, S.; Krisnangkura, K.

    2007-01-01

    Martin's equation, Δ sln g G=Δ sln g G o +zδ sln g G, is extended to cover vaporization free energy (Δ l g G). The extended equation is further expanded in terms of enthalpy and entropy and then used to correlate vaporization enthalpy (Δ l g H) and enthalpy of transfer from solution to gas (Δ sln g H). Data available in the literatures are used to validate and support the speculations derived from the proposed equation

  3. Quantification of the Effect of Pressure Wire Drift on the Diagnostic Performance of Fractional Flow Reserve, Instantaneous Wave-Free Ratio, and Whole-Cycle Pd/Pa.

    Science.gov (United States)

    Cook, Christopher M; Ahmad, Yousif; Shun-Shin, Matthew J; Nijjer, Sukhjinder; Petraco, Ricardo; Al-Lamee, Rasha; Mayet, Jamil; Francis, Darrel P; Sen, Sayan; Davies, Justin E

    2016-04-01

    Small drifts in intracoronary pressure measurements (±2 mm Hg) can affect stenosis categorization using pressure indices. This has not previously been assessed for fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), and whole-cycle distal pressure/proximal pressure (Pd/Pa) indices. Four hundred forty-seven stenoses were assessed with FFR, iFR, and whole-cycle Pd/Pa. Cut point values for significance were predefined as ≤0.8, Pa indices were recalculated and stenosis misclassification quantified. Median (±median absolute deviation) values for FFR, iFR, and whole-cycle Pd/Pa were 0.81 (±0.11), 0.90 (±0.07), and 0.93 (±0.06), respectively. For the cut point of FFR, iFR, and whole-cycle Pd/Pa, 34.6% (155), 50.1% (224), and 62.2% (278) of values, respectively, lay within ±0.05 U. With ±2 mm Hg pressure wire drift, 21% (94), 25% (110), and 33% (148) of the study population were misclassified with FFR, iFR, and whole-cycle Pd/Pa, respectively. Both FFR and iFR had significantly lower misclassification than whole-cycle Pd/Pa (PPa is more vulnerable to such reclassification than FFR and iFR. © 2016 The Authors.

  4. Vapor Detector

    Science.gov (United States)

    Waddell, H. M.; Garrard, G. C.; Houston, D. W.

    1982-01-01

    Detector eliminates need for removing covers to take samples. Detector is canister consisting of screw-in base and clear plastic tube that contains two colors of silica gel. Monoethylhydrazine and nitrogen tetroxide vapors are visually monitored with canister containing color-changing gels.

  5. Perfusion pressure and movement-induced hyperemia: evidence of limited vascular function and vasodilatory reserve with age

    Science.gov (United States)

    Groot, H. Jonathan; Trinity, Joel D.; Layec, Gwenael; Rossman, Matthew J.; Ives, Stephen J.

    2013-01-01

    To better understand the mechanisms contributing to reduced blood flow with age, this study sought to elucidate the impact of altered femoral perfusion pressure (FPP) on movement-induced hyperemia. Passive leg movement was performed in 10 young (22 ± 1 yr) and 12 old (72 ± 2 yr) healthy men for 2 min, with and without a posture-induced change in FPP (∼7 ± 1 ΔmmHg). Second-by-second measurements of central and peripheral hemodynamic responses were acquired noninvasively (finger photoplethysmography and Doppler ultrasound, respectively), with FPP confirmed in a subset of four young and four old subjects with arterial and venous catheters. Central hemodynamic responses (heart rate, stroke volume, cardiac output, mean arterial pressure) were not affected by age or position. The young exhibited a ∼70% greater movement-induced peak change in leg blood flow (ΔLBFpeak) in the upright-seated posture (supine: 596±68 ml/min; upright: 1,026 ± 85 ml/min). However, in the old the posture change did not alter ΔLBFpeak (supine: 417±42 ml/min; upright: 412±56 ml/min), despite the similar increases in FPP. Similarly, movement-induced peak change in leg vascular conductance was ∼80% greater for the young in the upright-seated posture (supine: 7.1 ± 0.8 ml·min−1·mmHg−1; upright: 12.8 ± 1.3 ml·min−1·mmHg−1), while the old again exhibited no difference between postures (supine: 4.7 ± 0.4 ml·min−1·mmHg−1; upright: 4.8 ± 0.5 ml·min−1·mmHg−1). Thus this study reveals that, unlike the young, increased FPP does not elicit an increase in movement-induced hyperemia or vasodilation in the old. In light of recent evidence that the majority of the first minute of passive movement-induced hyperemia is predominantly nitric oxide (NO) dependent in the young, these findings in the elderly may be largely due to decreased NO bioavailability, but this remains to be definitively determined. PMID:23262136

  6. Assessment of coronary fractional flow reserve using a monorail pressure catheter: the first-in-human ACCESS-NZ trial.

    Science.gov (United States)

    Menon, Madhav; Jaffe, Warwick; Watson, Tim; Webster, Mark

    2015-07-01

    FFR measurements have been limited by the handling characteristics of pressure wire (PW) systems, and by signal drift. This first-in-human study evaluated the safety and efficacy of a new monorail catheter (Navvus) to assess coronary FFR, compared to a PW system. Resting measurements were acquired with both systems. After initiating IV adenosine, FFR was measured with the PW alone, simultaneously using both systems, and again with PW alone. Any zero offset of PW or Navvus was then recorded. Navvus measured FFR in all patients in whom a PW recording was obtained (50 of 58 patients); there were no complications related to Navvus. Navvus FFR correlated well with PW FFR (r=0.87, slope 1.0, intercept -0.02). Within PW measurement accuracy, in no cases did Navvus FFR classify lesion significance differently from PW FFR. PW signal drift was significantly greater than Navvus (0.06±0.12 vs. 0.02±0.02, p=0.014). Navvus and PW FFR correlated well. Navvus had less sensor drift. This new catheter-based system offers an alternative method for measuring FFR, with some potential advantages over PW.

  7. Contribution of low vapor pressure-volatile organic compounds (LVP-VOCs) from consumer products to ozone formation in urban atmospheres

    Science.gov (United States)

    Shin, Hyeong-Moo; McKone, Thomas E.; Bennett, Deborah H.

    2015-05-01

    Because recent laboratory testing indicates that some low vapor pressure-volatile organic compounds (LVP-VOC) solvents readily evaporate at ambient conditions, LVP-VOCs used in some consumer product formulations may contribute to ozone formation. The goal of this study is to determine the fraction of LVP-VOCs available for ozone formation from the use of consumer products for two hypothetical emissions. This study calculates and compares the fraction of consumed product available for ozone formation as a result of (a) volatilization to air during use and (b) down-the-drain disposal. The study also investigates the impact of different modes of releases on the overall fraction available in ambient air for ozone formation. For the portion of the LVP-VOCs volatilized to air during use, we applied a multi-compartment mass-balance model to track the fate of emitted LVP-VOCs in a multimedia urban environment. For the portion of the LVP-VOCs disposed down the drain, we used a wastewater treatment plant (WWTP) fate model to predict the emission rates of LVP-VOCs to ambient air at WWTPs or at the discharge zone of the facilities and then used these results as emissions in the multimedia urban environment model. In a WWTP, the LVP-VOCs selected in this study are primarily either biodegraded or removed via sorption to sludge depending on the magnitude of the biodegradation half-life and the octanol-water partition coefficient. Less than 0.2% of the LVP-VOCs disposed down the drain are available for ozone formation. In contrast, when the LVP-VOC in a consumer product is volatilized from the surface to which it has been applied, greater than 90% is available for photochemical reactions either at the source location or in the downwind areas. Comparing results from these two modes of releases allows us to understand the importance of determining the fraction of LVP-VOCs volatilized versus disposed down the drain when the product is used by consumers. The results from this study

  8. High temperature and low pressure chemical vapor deposition of silicon nitride on AlGaN: Band offsets and passivation studies

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Pramod; Washiyama, Shun; Kaess, Felix; Hernandez-Balderrama, Luis H.; Haidet, Brian B.; Alden, Dorian; Franke, Alexander; Sarkar, Biplab; Kohn, Erhard; Collazo, Ramon; Sitar, Zlatko [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); Hayden Breckenridge, M. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919 (United States); REU, Physics Department at Wofford College, Spartanburg, South Carolina 29303 (United States)

    2016-04-14

    In this work, we employed X-ray photoelectron spectroscopy to determine the band offsets and interface Fermi level at the heterojunction formed by stoichiometric silicon nitride deposited on Al{sub x}Ga{sub 1-x}N (of varying Al composition “x”) via low pressure chemical vapor deposition. Silicon nitride is found to form a type II staggered band alignment with AlGaN for all Al compositions (0 ≤ x ≤ 1) and present an electron barrier into AlGaN even at higher Al compositions, where E{sub g}(AlGaN) > E{sub g}(Si{sub 3}N{sub 4}). Further, no band bending is observed in AlGaN for x ≤ 0.6 and a reduced band bending (by ∼1 eV in comparison to that at free surface) is observed for x > 0.6. The Fermi level in silicon nitride is found to be at 3 eV with respect to its valence band, which is likely due to silicon (≡Si{sup 0/−1}) dangling bonds. The presence of band bending for x > 0.6 is seen as a likely consequence of Fermi level alignment at Si{sub 3}N{sub 4}/AlGaN hetero-interface and not due to interface states. Photoelectron spectroscopy results are corroborated by current-voltage-temperature and capacitance-voltage measurements. A shift in the interface Fermi level (before band bending at equilibrium) from the conduction band in Si{sub 3}N{sub 4}/n-GaN to the valence band in Si{sub 3}N{sub 4}/p-GaN is observed, which strongly indicates a reduction in mid-gap interface states. Hence, stoichiometric silicon nitride is found to be a feasible passivation and dielectric insulation material for AlGaN at any composition.

  9. Vapor generation methods for explosives detection research

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

    2012-12-01

    The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

  10. Structure of the Clean and Oxygen-Covered Cu(100) Surface at Room Temperature in the Presence of Methanol Vapor in the 10-200 mTorr Pressure Range.

    Science.gov (United States)

    Eren, Baran; Kersell, Heath; Weatherup, Robert S; Heine, Christian; Crumlin, Ethan J; Friend, Cynthia M; Salmeron, Miquel B

    2018-01-18

    Using ambient pressure X-ray photoelectron spectroscopy (APXPS) and high pressure scanning tunneling microscopy (HPSTM), we show that in equilibrium with 0.01-0.2 Torr of methanol vapor, at room temperature, the Cu(100) surface is covered with methoxy species forming a c(2 × 2) overlayer structure. In contrast, no methoxy is formed if the surface is saturated with an ordered oxygen layer, even when the methanol pressure is 0.2 Torr. At oxygen coverages below saturation, methanol dissociates and reacts with the atomic oxygen, producing methoxy and formate on the surface, and formaldehyde that desorbs to the gas phase. Unlike the case of pure carbon monoxide and carbon dioxide, methanol does not induce the restructuring of the Cu(100) surface. These results provide insight into catalytic anhydrous production of aldehydes.

  11. 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

    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...

  12. Vapor phase spectra and the pressure-temperature dependence of long-chain carboxyllic acids studied by a CO laser and the photoacoustic heat-pipe detector.

    NARCIS (Netherlands)

    Jalink, H.; Bicanic, D.; Franko, M.; Bozoki, Z.

    1995-01-01

    A resonant photoacoustic heat-pipe (PAHP) cell was constructed and used for spectral studies of four long-chain saturated fatty acids (C10:0 to C16:0) at CO laser wavelengths and temperatures above that of the ambient. Vapor-phase absorption spectra were recorded at temperatures of 383 K for capric

  13. Impact of air and water vapor environments on the hydrophobicity of surfaces.

    Science.gov (United States)

    Weisensee, Patricia B; Neelakantan, Nitin K; Suslick, Kenneth S; Jacobi, Anthony M; King, William P

    2015-09-01

    Droplet wettability and mobility play an important role in dropwise condensation heat transfer. Heat exchangers and heat pipes operate at liquid-vapor saturation. We hypothesize that the wetting behavior of liquid water on microstructures surrounded by pure water vapor differs from that for water droplets in air. The static and dynamic contact angles and contact angle hysteresis of water droplets were measured in air and pure water vapor environments inside a pressure vessel. Pressures ranged from 60 to 1000 mbar, with corresponding saturation temperatures between 36 and 100°C. The wetting behavior was studied on four hydrophobic surfaces: flat Teflon-coated, micropillars, micro-scale meshes, and nanoparticle-coated with hierarchical micro- and nanoscale roughness. Static advancing contact angles are 9° lower in the water vapor environment than in air on a flat surface. One explanation for this reduction in contact angles is water vapor adsorption to the Teflon. On microstructured surfaces, the vapor environment has little effect on the static contact angles. In all cases, variations in pressure and temperature do not influence the wettability and mobility of the water droplets. In most cases, advancing contact angles increase and contact angle hysteresis decreases when the droplets are sliding or rolling down an inclined surface. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Recent advances in vapor intrusion site investigations.

    Science.gov (United States)

    McHugh, Thomas; Loll, Per; Eklund, Bart

    2017-12-15

    Our understanding of vapor intrusion has evolved rapidly since the discovery of the first high profile vapor intrusion sites in the late 1990s and early 2000s. Research efforts and field investigations have improved our understanding of vapor intrusion processes including the role of preferential pathways and natural barriers to vapor intrusion. This review paper addresses recent developments in the regulatory framework and conceptual model for vapor intrusion. In addition, a number of innovative investigation methods are discussed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Comparative analysis of high pressure sodium vapor lamps and mercury vapor lamp with the solid state (LED) in the public lighting systems; Analise comparativa das lampadas de vapor de sodio a alta pressao e de vapor de mercurio com a lampada a estado solido (LED) em sistemas de iluminacao publica

    Energy Technology Data Exchange (ETDEWEB)

    Damato, J.C.; Bueno, J.E.; Astorga, O.A.M. [Universidade Estadual Paulista (LESIP/UNESP), Guaratingueta, SP (Brazil). Lab. de Eficiencia Energetica em Sistemas de Iluminacao Publica; Ricciulli, D.L.S. [Universidade Estadual Paulista (DEE/UNESP), Guaratingueta, SP (Brazil). Dept. de Engenharia Eletrica

    2009-07-01

    The necessity of energy conservation in Brazilian electric sector, with the intention to diminish the resources of generation investments, has going to use of electric energy conservation programs, being most important PROCEL - a national program of electric conservation energy by ELETROBRAS, and inside this, a national program for public illumination and efficient traffic signaling - named 'Reluz'. This program looks for a more efficient implantation of public lighting systems, that requires the use of lamp technologies that present a greater value in a relation between lumen/watt relation and then beyond providing economy, due to low consumption of electric energy. Besides technologies that are appearing, the inclusion of LED lamps, which offers a great application potential, comes blunting as improvement alternative, being that the next public illumination parks will be able count on these lamps associates to the high-pressure sodium lamps and other types currently used. (author)

  16. CH3NH3I treatment temperature of 70 °C in low-pressure vapor-assisted deposition for mesoscopic perovskite solar cells

    Science.gov (United States)

    Jin, Wenbin; Zou, Xiaoping; Bai, Xiao; Yang, Ying; Chen, Dan

    2018-01-01

    Herein, we report a modified vapor-assisted deposition method to fabricate CH3NH3PbI3 film at 70 °C in a vacuum drying oven. The modified method has excellent operability and expandability in preparing perovskite solar cells. The CH3NH3I treatment temperature is 130 °C or 150 °C in conventional method, but we reduced the temperature to 70 °C in the modified vapor-assisted method. Meanwhile, the quality of CH3NH3PbI3 films prepared via the modified method is superior to that of CH3NH3PbI3 films of solution-processed method.

  17. Thermochemical Energy Storage with CaO/Ca(OH)2 – Experimental investigation of the thermal capability at low vapor pressures in a lab scale reactor

    OpenAIRE

    Schmidt, Matthias; Andrea, Gutierrez; Linder, Marc

    2017-01-01

    The reversible reaction of calcium hydroxide (Ca(OH)2) to calcium oxide (CaO) and water vapor is well known in the context of thermochemical energy storage. Cheap material costs, a theoretically very high energy density and the potentially wide temperature range of the reaction imply that the storage system could be beneficial for many high temperature processes. For example the system could be applied to store and reutilize industrial waste heat or as an alternative storage solution in futur...

  18. Modified headspace solid-phase microextraction for the determination of quantitative relationships between components of mixtures consisting of alcohols, esters, and ethers - impact of the vapor pressure difference of the compounds.

    Science.gov (United States)

    Dawidowicz, Andrzej Lech; Szewczyk, Joanna; Dybowski, Michal P

    2017-07-01

    The quantitative relationship between analytes established by the headspace solid-phase microextraction procedure for multicomponent mixtures depends not only on the character and strength of interactions of individual components with solid-phase microextraction fiber but also on their vapor pressure in the applied headspace solid-phase microextraction system. This study proves that vapor pressure is of minor importance when the sample is dissolved/suspended in a low-volatility liquid of the same physicochemical character as that of the used solid phase microextraction fiber coating. It is demonstrated for mixtures of alcohols, esters, ethers and their selected representatives by applying a headspace solid-phase microextraction system composed of Carbowax fiber and sample solutions in polyethyleneglycol. The observed differences in quantitative relations between components of the examined mixtures established by their direct analysis and by modified headspace solid-phase microextraction are insignificant (F exp  difference between individual components of the examined mixture in the applied headspace solid phase microextraction system due to low components concentration in polyethyleneglycol suspensions (Raoult's law) and due to strong specific interactions of analyte molecules with polyethyleneglycol molecules. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Correlation between thallium-201 myocardial perfusion defects and the functional severity of coronary artery stenosis as assessed by pressure-derived myocardial fractional flow reserve

    International Nuclear Information System (INIS)

    Yanagisawa, Hidefumi; Chikamori, Taishiro; Tanaka, Nobuhiro

    2002-01-01

    Although a relationship between the coronary pressure-derived fractional flow reserve (FFR) and the presence of myocardial ischemia as demonstrated by radionuclide imaging has been reported in a select group of patients, it remains to be established whether this relation also holds true in actual clinical settings with a heterogeneous group of patients. Accordingly, 194 coronary vessels and their supply territories were evaluated in 165 consecutive patients with suspected or known coronary artery disease. An FFR 201 Tl (p 201 Tl reversibility score (r=-0.62; p<0.0001). These results suggest that the FFR has a significant relationship with scintigraphic evidence of myocardial ischemia and can be regarded as a marker of its presence or absence in patients in actual clinical settings. (author)

  20. Validation of Hiriart equation to compute steam production by the lip pressure method; Validacion de la ecuacion de Hiriart para calculo de gasto de vapor por el metodo de presion de labio

    Energy Technology Data Exchange (ETDEWEB)

    Flores Armenta, Magaly [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)

    1996-09-01

    Mainly in new geothermal wells, it is necessary to evaluate the production in a very fast, simple and not expensive way, to know the convenience to install surface equipment, such as silencers and separators, to drive the steam to the commercial gathering system. In practice, one of the most known methods is the lip pressure one, which requires a simple set of installations. The objective of this paper is to validate the steam flow rate calculated by the lip pressure method, with respect to the ASME method. The ASME method is known for its accuracy, and is done by measuring the steam and liquid after a high pressure separator, by an orifice plate of known diameter and a triangular weir. Results of the validation show up the feasibility of application of the lip pressure method by using a simple adjustment equation. Percentage of mistake results less than 1%, without any notable influence of the production enthalpy. That equation to be applied in a general case, is as follows: Q{nu} =(20642)(F*P*D{sup 2}/{radical}h-2000). For the particular case of the Los Azufres geothermal field, the equation is: Q{nu}= 810*P*D{sup 2} [Espanol] En los pozos geotermicos, principalmente en los nuevos, es necesario evaluar su produccion de manera rapida, sencilla y economica, para determinar la conveniencia de instalar equipo superficial, como separadores, silenciadores, etc., que permita la integracion del vapor al sistema comercial de generacion electrica. Para fines practicos uno de los metodos mas conocidos es el de presion de labio, que solo requiere un arreglo sencillo de instalaciones superficiales. En este documento se validan y ajustan los calculos de produccion de vapor por ese metodo de presion de labio, con respecto a las mediciones exactas efectuadas con el metodo ASME. Este ultimo es reconocido internacionalmente por su precision, y se lleva a cabo separando la mezcla obtenida en superficie en un recipiente a presion para medir el vapor a traves de una placa de orificio

  1. Petroleum Vapor Intrusion

    Science.gov (United States)

    One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

  2. 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.

  3. Rare earth vapor laser studies

    International Nuclear Information System (INIS)

    Krupke, W.F.; Jacobs, R.R.

    1977-01-01

    The fluorescence decay rates of vapor phase neodymium aluminum chloride complex (Nd-Al-Cl) and neodymium-thd-chelate have been measured as functions of temperature, partial pressure and optical excitation intensity. Fluorescence quenching due to both ground and excited state collisions was observed in Nd-Al-Cl vapor. In constrast, quenching in the Nd-thd vapor was found to be dominated by multiquantum excitation of molecular vibrations. The fluorescence kinetics of Tb-Al-Cl vapor have also been examined under conditions of intense excitation of terbium 5d levels by a KrF laser source. Both prompt and delayed fluorescence of the 4f 8 ( 5 D 4 ) metastable level were observed together with evidence of excited-state collisional quenching. In laser amplifier experiments, a transient (greater than or equal to 10 μsec) population inversion was produced in Nd-Al-Cl vapor with a small signal gain coefficient greater than or equal to 0.25%/cm and a stored energy density approximately equal to 35 J/liter. Available data for the rare earth vapors are related to scaling requirements of large amplifiers for laser fusion application

  4. A Flash Vaporization System for Detonation of Hydrocarbon Fuels in a Pulse Detonation Engine

    National Research Council Canada - National Science Library

    Tucker, Kelly C

    2005-01-01

    ...) with low vapor pressure, kerosene based jet fuels. These fuels have a low vapor pressure and the performance of a liquid hydrocarbon fueled PDE is significantly hindered by the presence of fuel droplets...

  5. Quantitative absorption spectroscopy of residual water vapor in high-purity gases: pressure broadening of the 1.39253-microm H2O transition by N2, HCl, HBr, Cl2, and O2.

    Science.gov (United States)

    Vorsa, Vasil; Dheandhanoo, Seksan; Ketkar, Suhas N; Hodges, Joseph T

    2005-02-01

    We determined the respective pressure-broadening coefficients of HCl, HBr, Cl2, and O2 (expressed relative to that of the reference gas N2) for the (v1,v2,v3)J(Ka,Kc) = (0,0,0)3(0,3) --> (1,0,1)2(0,2) rovibrational transition of H2 16O that occurs at 1.39253 microm. The experiment used a continuous-wave cavity ring-down spectroscopy analyzer to measure the peak absorption losses as a function of added moisture concentration. The measured pressure-broadening coefficients for HCl, HBr, Cl2, and O2 are, respectively, 2.76, 2.48, 1.39, and 0.49 times that of the N2 pressure-broadening coefficient, and detection limits for water vapor range from 0.22 nmol mol(-1) for O2 matrix gas to 2.3 nmol mol(-1) for HBr matrix gas. The degradation of the detection limit (relative to the N2 matrix gas) is ascribed to a pressure-broadening-induced reduction in peak absorption cross section and to elevated background loss from the matrix gas.

  6. A Lithium Vapor Box Divertor Similarity Experiment

    Science.gov (United States)

    Cohen, Robert A.; Emdee, Eric D.; Goldston, Robert J.; Jaworski, Michael A.; Schwartz, Jacob A.

    2017-10-01

    A lithium vapor box divertor offers an alternate means of managing the extreme power density of divertor plasmas by leveraging gaseous lithium to volumetrically extract power. The vapor box divertor is a baffled slot with liquid lithium coated walls held at temperatures which increase toward the divertor floor. The resulting vapor pressure differential drives gaseous lithium from hotter chambers into cooler ones, where the lithium condenses and returns. A similarity experiment was devised to investigate the advantages offered by a vapor box divertor design. We discuss the design, construction, and early findings of the vapor box divertor experiment including vapor can construction, power transfer calculations, joint integrity tests, and thermocouple data logging. Heat redistribution of an incident plasma-based heat flux from a typical linear plasma device is also presented. This work supported by DOE Contract No. DE-AC02-09CH11466 and The Princeton Environmental Institute.

  7. 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...

  8. 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...

  9. Isobaric vapor liquid equilibria data for the binary system (glycidyl butyrate + acetone, glycidyl butyrate + carbon tetrachloride, glycidyl butyrate + chloroform) at atmospheric pressure 101 kPa

    Science.gov (United States)

    Huang, Qiang; Meng, Qingyi; Ban, Chunlan; Zhang, Rui; Gao, Yingyu

    2016-09-01

    Isobaric vapor liquid equilibria (VLE) for the binary mixtures of glycidyl butyrate(1) + acetone(2), glycidyl butyrate(1) + carbon tetrachloride(2) and glycidyl butyrate(1) + chloroform(2) at 101 kPa were studied. The experimental data were satisfactorily correlated with the models of Wilson, NRTL and UNIQUAC activity coefficients. The activity coefficients for the equilibrium data were obtained by the nonlinear least square method. The average relative deviations between experimental temperatures and calculated temperatures by the Wilson, NRTL and UNIQUAC models were 0.16, 0.16, 0.23% for glycidyl butyrate(1) + chloroform( 2), 0.38, 0.12, 0.27% for glycidylbutyrate(1) + carbon tetrachloride(2), and 0.67, 0.13, 0.54% for glycidyl butyrate(1) + acetone(2). Azeotrope behavior was not found for these systems. The thermodynamic consistency of the correlations was checked by the Herrington's area test.

  10. LINE SHAPES OF DOPPLER-FREE RESONANCE IN SRFM: STRONG ATOM-WALL INTERACTION AND PRESSURE EFFECT ON THE FREQUENCY SHIFT OF AN ALKALI VAPOR

    Directory of Open Access Journals (Sweden)

    B BOUHAFS

    2003-12-01

    Full Text Available The attractive potential energy between the atoms of rubidium vapor and a dielectric wall has been investigated by monitoring the reflection light at the interface. The atom- wall interaction potential of the form V(z = - C /z3 (z: atom-wall allows to predict experimental results only for weak regime, i.e., where C<< 0.2 kHzmm3. In the strong interaction case, the dispersive line shape is turned into an absorption-type line shape. The influence of atomic density on the shift of  the selective reflection resonance  relatively to the frequency of unperturbed atomic transition is found to be red with a negative slope. This technique opens the way to characterize the windows made of different materials thin films.

  11. (Vapor + liquid) equilibrium for the binary systems {l_brace}water + glycerol{r_brace} and {l_brace}ethanol + glycerol, ethyl stearate, and ethyl palmitate{r_brace} at low pressures

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Renata; Santos, Priscilla G. dos; Mafra, Marcos R. [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Cardozo-Filho, Lucio [Department of Chemical Engineering, Maringa State University (UEM), Av. Colombo 5790, 87020-900 Maringa, PR (Brazil); Corazza, Marcos L., E-mail: corazza@ufpr.br [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil)

    2011-12-15

    Highlights: > We measured VLE for the binary system {l_brace}ethyl stearate and palmitate + ethanol{r_brace}. > The boiling temperatures were obtained using Othmer-type ebuliometer. > The experimental data were modeled using NRTL, UNIQUAC, and UNIFAC models. - Abstract: This work reports the experimental measurements {l_brace}(vapor + liquid) equilibrium{r_brace} for the systems {l_brace}water(1) + glycerol(2){r_brace}, {l_brace}ethanol(1) + glycerol(2){r_brace}, {l_brace}ethanol(1) + ethyl stearate(2){r_brace}, and {l_brace}ethanol(1) + ethyl palmitate(2){r_brace}. Boiling temperatures were measured using an Othmer-type ebulliometer over a pressure range of 14 kPa to 96 kPa. The experimental data were well correlated using the NRTL and UNIQUAC models. The performance of the UNIFAC-Dortmund model in relation to predicting the phase equilibrium of the systems was also studied.

  12. Cognitive Functions and Cognitive Reserve in Relation to Blood Pressure Components in a Population-Based Cohort Aged 53 to 94 Years

    Directory of Open Access Journals (Sweden)

    Nunzia Giordano

    2012-01-01

    Full Text Available In 288 men and women from general population in a cross-sectional survey, all neuropsychological tests were negatively associated with age; memory and executive function were also positively related with education. The hypertensives (HT were less efficient than the normotensives (NT in the test of memory with interference at 10 sec (MI-10 (−33%, P=0.03, clock drawing test (CLOX (−28%, P<0.01, and mini-mental state examination (MMSE (−6%, P=0.02. Lower MMSE, MI-10, and CLOX were predicted by higher systolic (odds ratio, OR, 0.97, P=0.02; OR 0.98, P<0.005; OR 0.95, P<0.001 and higher pulse blood pressure (BP (OR 0.97, P=0.02; OR 0.97, P<0.01; and 0.95, P<0.0001. The cognitive reserve index (CRI was 6% lower in the HT (P=0.03 and was predicted by higher pulse BP (OR 0.82, P<0.001. The BP vectors of lower MMSE, MI-10, and CLOX were directed towards higher values of systolic and diastolic BP, that of low CRI towards higher systolic and lower diastolic. The label of hypertension and higher values of systolic or pulse BP are associated to worse memory and executive functions. Higher diastolic BP, although insufficient to impair cognition, strengthens this association. CRI is predicted by higher systolic BP associated to lower diastolic BP.

  13. Correlation between thallium-201 myocardial perfusion defects and the functional severity of coronary artery stenosis as assessed by pressure-derived myocardial fractional flow reserve

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, Hidefumi; Chikamori, Taishiro; Tanaka, Nobuhiro [Tokyo Medical Coll. (Japan)] [and others

    2002-12-01

    Although a relationship between the coronary pressure-derived fractional flow reserve (FFR) and the presence of myocardial ischemia as demonstrated by radionuclide imaging has been reported in a select group of patients, it remains to be established whether this relation also holds true in actual clinical settings with a heterogeneous group of patients. Accordingly, 194 coronary vessels and their supply territories were evaluated in 165 consecutive patients with suspected or known coronary artery disease. An FFR <0.75, which is regarded as indicative of functionally important stenosis, showed a significant correlation with the redistribution of {sup 201}Tl (p<0.0001), with a sensitivity of 79% and specificity of 73%. In 70 infarct-related coronary arteries, the sensitivity and specificity were 79% and 75%, respectively, whereas in the 124 remaining vessels that were not related to the myocardial infarct, the sensitivity and specificity were 80% and 72%, respectively. In addition, the FFR exhibited a significant inverse correlation with the {sup 201}Tl reversibility score (r=-0.62; p<0.0001). These results suggest that the FFR has a significant relationship with scintigraphic evidence of myocardial ischemia and can be regarded as a marker of its presence or absence in patients in actual clinical settings. (author)

  14. VOC composition of current motor vehicle fuels and vapors, and collinearity analyses for receptor modeling.

    Science.gov (United States)

    Chin, Jo-Yu; Batterman, Stuart A

    2012-03-01

    The formulation of motor vehicle fuels can alter the magnitude and composition of evaporative and exhaust emissions occurring throughout the fuel cycle. Information regarding the volatile organic compound (VOC) composition of motor fuels other than gasoline is scarce, especially for bioethanol and biodiesel blends. This study examines the liquid and vapor (headspace) composition of four contemporary and commercially available fuels: gasoline (gasoline), ultra-low sulfur diesel (ULSD), and B20 (20% soy-biodiesel and 80% ULSD). The composition of gasoline and E85 in both neat fuel and headspace vapor was dominated by aromatics and n-heptane. Despite its low gasoline content, E85 vapor contained higher concentrations of several VOCs than those in gasoline vapor, likely due to adjustments in its formulation. Temperature changes produced greater changes in the partial pressures of 17 VOCs in E85 than in gasoline, and large shifts in the VOC composition. B20 and ULSD were dominated by C(9) to C(16)n-alkanes and low levels of the aromatics, and the two fuels had similar headspace vapor composition and concentrations. While the headspace composition predicted using vapor-liquid equilibrium theory was closely correlated to measurements, E85 vapor concentrations were underpredicted. Based on variance decomposition analyses, gasoline and diesel fuels and their vapors VOC were distinct, but B20 and ULSD fuels and vapors were highly collinear. These results can be used to estimate fuel related emissions and exposures, particularly in receptor models that apportion emission sources, and the collinearity analysis suggests that gasoline- and diesel-related emissions can be distinguished. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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

  17. 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 ...

  18. Vapor-barrier Vacuum Isolation System

    Science.gov (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  19. 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

  20. 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

  1. Improving Liquid Entry Pressure of Polyvinylidene Fluoride (PVDF Membranes by Exploiting the Role of Fabrication Parameters in Vapor-Induced Phase Separation VIPS and Non-Solvent-Induced Phase Separation (NIPS Processes

    Directory of Open Access Journals (Sweden)

    Faisal Abdulla AlMarzooqi

    2017-02-01

    Full Text Available Polyvinylidene fluoride (PVDF is a popular polymer material for making membranes for several applications, including membrane distillation (MD, via the phase inversion process. Non-solvent-induced phase separation (NIPS and vapor-induced phase separation (VIPS are applied to achieve a porous PVDF membrane with low mass-transfer resistance and high contact angle (hydrophobicity. In this work, firstly, the impacts of several preparation parameters on membrane properties using VIPS and NIPS were studied. Then, the performance of the selected membrane was assessed in a lab-scale direct-contact MD (DCMD unit. The parametric study shows that decreasing PVDF concentration while increasing both relative humidity (RH and exposure time increased the contact angle and bubble-point pore size (BP. Those trends were investigated further by varying the casting thickness. At higher casting thicknesses and longer exposure time (up to 7.5 min, contact angle (CA increased but BP significantly decreased. The latter showed a dominant trend leading to liquid entry pressure (LEP increase with thickness.

  2. Henry's law constant, octanol-air partition coefficient and supercooled liquid vapor pressure of carbazole as a function of temperature: application to gas/particle partitioning in the atmosphere.

    Science.gov (United States)

    Odabasi, Mustafa; Cetin, Banu; Sofuoglu, Aysun

    2006-02-01

    The Henry's law constant for carbazole was experimentally determined between 5 and 35 degrees C using a gas-stripping technique. The following equation was obtained for dimensionless Henry's law constant (H') versus temperature (T, K): ln H' = -3982(T,K)(-1) + 1.01. Temperature-dependent octanol-air partition coefficients (KOA) and supercooled liquid vapor pressures (PL,Pa) of carbazole were also determined using the GC retention time method. The temperature dependence of KOA and PL were explained by the following: log KOA = 4076/(T,K) - 5.65, log PL(Pa) = -3948(T,K)(- 1) + 11.48. The gas and particle-phase carbazole concentrations measured previously in Chicago, IL in 1995 was used for gas/particle partitioning modeling. Octanol based absorptive partitioning model consistently underpredicted the gas/particle partition coefficients (Kp) for all sampling periods. However, overall there was a good agreement between the measured Kp and soot-based model predictions.

  3. Oxygen-assisted low-pressure chemical vapor deposition for the low-temperature direct growth of graphitic nanofibers on fluorine-doped tin oxide glass as a counter electrode for dye-sensitized solar cell

    Science.gov (United States)

    Chen, Chih-Sheng; Hsieh, Chien-Kuo

    2014-11-01

    In this paper, we report an oxygen-assisted low-pressure chemical vapor deposition (LPCVD) method for the direct growth of graphitic nanofibers (GNFs) on a fluorine-doped tin oxide (FTO) glass substrate at a low temperature (550 °C). By adding moderate concentrations of oxygen in a gas mixture of argon, ethylene, and hydrogen during LPCVD, an extremely dense GNF forest can be obtained on a nickel-coated FTO glass substrate. Though this process, the graphitic nanofibers are grown homogenously on a large area of FTO glass. It was observed that oxygen-assisted LPCVD leads to the direct growth of high-quality GNFs as a counter electrode for dye-sensitized solar cells (DSSCs). In combination with an N719 dye-sensitized TiO2 working electrode and an iodine-based electrolyte, the DSSC with a GNF counter electrode showed a power conversion efficiency of 5.51% under AM 1.5 (100 mW cm-2) illumination, which approached that of the DSSC with a Pt counter electrode (5.44%). The results demonstrated that our directly grown GNFs could be promising candidates for counter electrodes to achieve high performance in DSSCs.

  4. Modelling and simulation of the steam line, the high and low pressure turbines and the pressure regulator for the SUN-RAH nucleo electric university simulator; Modelado y simulacion de la linea de vapor, las turbinas de alta y de baja presion y el regulador de presion para el simulador universitario de nucleo electricas SUN RAH

    Energy Technology Data Exchange (ETDEWEB)

    Lopez R, A. [DEPFI, Campus Morelos, en IMTA Jiutepec, Morelos, UNAM (Mexico)]. e-mail: andyskamx@yahoo.com.mx

    2003-07-01

    In the following article the development of a simulator that allows to represent the dynamics of the following systems: steam line, nozzle, vapor separator, reheater, high pressure turbine, low pressure turbine, power generator and the pressure regulator of a nucleo electric power station. We start from the supposition that this plant will be modeled from a nuclear reactor type BWR (Boiling Water Reactor), using models of reduced order that represent the more important dynamic variables of the physical processes that happen along the steam line until the one generator. To be able to carry out the simulation in real time the Mat lab mathematical modeling software is used, as well as the specific simulation tool Simulink. It is necessary to point out that the platform on which the one is executed the simulator is the Windows operating system, to allow the intuitive use that only this operating system offers. The above-mentioned obeys to that the objective of the simulator it is to help the user to understand some of the dynamic phenomena that are present in the systems of a nuclear plant, and to provide a tool of analysis and measurement of variables to predict the desirable behavior of the same ones. The model of a pressure controller for the steam lines, the high pressure turbine and the low pressure turbine is also presented that it will be the one in charge of regulating the demand of the system according to the characteristics and critic restrictions of safety and control, assigned according to those wanted parameters of performance of this system inside the nucleo electric plant. This simulator is totally well defined and it is part of the University student nucleo electric simulator with Boiling Water Reactor (SUN-RAH), an integral project and of greater capacity. (Author)

  5. Vapor pressure and specific electrical conductivity in the solid and molten H2O-CsH2PO4-CsPO3 system—a novel electrolyte for water electrolysis at ~ 225–400 °C

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey Valerievich; Berg, Rolf W.; Bjerrum, Niels J.

    2018-01-01

    cells. Freshly prepared 99.7 ± 0.3% gravimetric pure CDP with correct X-ray diffraction and DSC diagram melted at ~ 345 °C. The vapor pressures, above CDP alone and mixed with 20–50 mol% CsPO3 or 13 mol% H2O, were determined in sealed ampoules up to 355 °C by means of Raman spectroscopy based...

  6. Low-voltage back-gated atmospheric pressure chemical vapor deposition based graphene-striped channel transistor with high-κ dielectric showing room-temperature mobility > 11 000 cm2/V·s

    KAUST Repository

    Smith, Casey

    2013-07-23

    Utilization of graphene may help realize innovative low-power replacements for III-V materials based high electron mobility transistors while extending operational frequencies closer to the THz regime for superior wireless communications, imaging, and other novel applications. Device architectures explored to date suffer a fundamental performance roadblock due to lack of compatible deposition techniques for nanometer-scale dielectrics required to efficiently modulate graphene transconductance (gm) while maintaining low gate capacitance-voltage product (CgsVgs). Here we show integration of a scaled (10 nm) high-κ gate dielectric aluminum oxide (Al2O3) with an atmospheric pressure chemical vapor deposition (APCVD)-derived graphene channel composed of multiple 0.25 μm stripes to repeatedly realize room-temperature mobility of 11 000 cm 2/V·s or higher. This high performance is attributed to the APCVD graphene growth quality, excellent interfacial properties of the gate dielectric, conductivity enhancement in the graphene stripes due to low t ox/Wgraphene ratio, and scaled high-κ dielectric gate modulation of carrier density allowing full actuation of the device with only ±1 V applied bias. The superior drive current and conductance at Vdd = 1 V compared to other top-gated devices requiring undesirable seed (such as aluminum and poly vinyl alcohol)-assisted dielectric deposition, bottom gate devices requiring excessive gate voltage for actuation, or monolithic (nonstriped) channels suggest that this facile transistor structure provides critical insight toward future device design and process integration to maximize CVD-based graphene transistor performance. © 2013 American Chemical Society.

  7. Estimating evaporative vapor generation from automobiles based on parking activities.

    Science.gov (United States)

    Dong, Xinyi; Tschantz, Michael; Fu, Joshua S

    2015-07-01

    A new approach is proposed to quantify the evaporative vapor generation based on real parking activity data. As compared to the existing methods, two improvements are applied in this new approach to reduce the uncertainties: First, evaporative vapor generation from diurnal parking events is usually calculated based on estimated average parking duration for the whole fleet, while in this study, vapor generation rate is calculated based on parking activities distribution. Second, rather than using the daily temperature gradient, this study uses hourly temperature observations to derive the hourly incremental vapor generation rates. The parking distribution and hourly incremental vapor generation rates are then adopted with Wade-Reddy's equation to estimate the weighted average evaporative generation. We find that hourly incremental rates can better describe the temporal variations of vapor generation, and the weighted vapor generation rate is 5-8% less than calculation without considering parking activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Terahertz radiation in alkali vapor plasmas

    International Nuclear Information System (INIS)

    Sun, Xuan; Zhang, X.-C.

    2014-01-01

    By taking advantage of low ionization potentials of alkali atoms, we demonstrate terahertz wave generation from cesium and rubidium vapor plasmas with an amplitude nearly one order of magnitude larger than that from nitrogen gas at low pressure (0.02–0.5 Torr). The observed phenomena are explained by the numerical modeling based upon electron tunneling ionization

  9. Vapor Growth of III Nitrides

    Science.gov (United States)

    Cai, Dang; Zheng, Lili; Zhang, Hui

    Good understanding of transport phenomena in vapor deposition systems is critical to fast and effective crystal growth system design. Transport phenomena are complicated and are related to operating conditions, such as temperature, velocity, pressure, and species concentration, and geometrical conditions, such as reactor geometry and source-substrate distance. Due to the limited in situ experimental monitoring, design and optimization of growth is mainly performed through semi-empirical and trial-and-error methods. Such an approach is only able to achieve improvement in the deposition sequence and cannot fulfill the increasingly stringent specifications required in industry. Numerical simulation has become a powerful alternative, as it is fast and easy to obtain critical information for the design and optimization of the growth system. The key challenge in vapor deposition modeling lies in developing an accurate simulation model of gas-phase and surface reactions, since very limited kinetic information is available in the literature. In this chapter, GaN thin-film growth by iodine vapor-phase epitaxy (IVPE) is used as an example to present important steps for system design and optimization by the numerical modeling approach. The advanced deposition model will be presented for multicomponent fluid flow, homogeneous gas-phase reaction inside the reactor, heterogeneous surface reaction on the substrate surface, heat transfer, and species transport. Thermodynamic and kinetic analysis will be presented for gas-phase and surface reactions, together with a proposal for the reaction mechanism based on experiments. The prediction of deposition rates is presented. Finally, the surface evolution of film growth from vapor is analyzed for the case in which surface diffusion determines crystal grain size and morphology. Key control parameters for film instability are identified for quality improvement.

  10. A heated vapor cell unit for DAVLL in atomic rubidium

    OpenAIRE

    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 D2 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...

  11. 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.

  12. Modeling vapor-liquid interfaces with the gradient theory in combination with the CPA equation of state

    DEFF Research Database (Denmark)

    Queimada, Antonio; Miqueu, C; Marrucho, IM

    2005-01-01

    With the final purpose of describing the important aqueous + hydrocarbon liquid-liquid interfaces, the gradient theory was combined with the Cubic-Plus-Association equation of state (CPA EOS), taking advantage of the correct representation of interfacial tensions provided by the gradient theory...... and discussed. The good description of equilibrium properties such as vapor pressure and liquid and vapor phase densities is shown in the full range of the vapor-liquid saturation line. For non-associating components, results are compared with those from the Soave-Redlich-Kwong and Peng-Robinson equations...... of state. A correlation for the influence parameter is presented from which surface tensions can be obtained in a broad temperature range with average errors smaller than 1%. (c) 2004 Elsevier B.V. All rights reserved....

  13. 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.

  14. Method for Determining Vaporization Parameters

    Data.gov (United States)

    National Aeronautics and Space Administration — An accurate method of measuring vaporization coefficients will be very useful to each of these disciplines: Cosmochemistry,Evaporative Vapor Deposition, Durability...

  15. Numerical simulation of superheated vapor bubble rising in stagnant liquid

    Science.gov (United States)

    Samkhaniani, N.; Ansari, M. R.

    2017-09-01

    In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

  16. Atmospheric water vapor absorption at 1.3 microm.

    Science.gov (United States)

    Bragg, S L; Kelley, J D

    1987-02-01

    Absolute absorption cross sections for water vapor and water vapor/air mixtures were measured in a frequency range encompassing that of the chemically pumped atomic iodine laser. Measurements were made with a temperature-controlled multipass absorption cell and a high-resolution Fourier transform spectrometer. The measurements covered a broad range of water vapor and air pressures. Several techniques of data analysis were used, and the absorption cross section of 2 kPa of water vapor in an atmosphere of air was determined to be 1.1 +/- 0.2 x 10(-24) cm(2) . In this paper, an expression is derived which allows estimation of the absorption cross section for any pressure of water vapor and air.

  17. Molecular dynamics study of the vaporization of an ionic drop

    Science.gov (United States)

    Galamba, N.

    2010-09-01

    The melting of a microcrystal in vacuum and subsequent vaporization of a drop of NaCl were studied through molecular dynamics simulations with the Born-Mayer-Huggins-Tosi-Fumi rigid-ion effective potential. The vaporization was studied for a single isochor at increasing temperatures until the drop completely vaporized, and gaseous NaCl formed. Examination of the vapor composition shows that the vapor of the ionic drop and gaseous NaCl are composed of neutral species, the most abundant of which, ranging from simple NaCl monomers (ion pairs) to nonlinear polymers, (NanCln)n=2-4. The enthalpies of sublimation, vaporization, and dissociation of the different vapor species are found to be in reasonable agreement with available experimental data. The decrease of the enthalpy of vaporization of the vapor species, with the radius of the drop decrease, accounts for a larger fraction of trimers and tetramers than that inferred from experiments. Further, the rhombic dimer is significantly more abundant than its linear isomer although the latter increases with the temperature. The present results suggest that both trimers and linear dimers may be important to explain the vapor pressure of molten NaCl at temperatures above 1500 K.

  18. Apparatus for controlling vapor temperature in a nuclear power plant

    International Nuclear Information System (INIS)

    Mega, Tsuneo.

    1975-01-01

    Object: To enable to maintain temperature of vapor from a heater and a reheater in a given allowable range to effect immediate and stable following control in response to variation in load. Structure: Vapor temperature from a superheater entering a high pressure turbine and vapor temperature from a reheater entering a low pressure turbine are detected by a first and a second detectors, respectively, these temperatures being compared and operated with a reference value separately determined to feed a control signal in proportion to flow rate of heating medium to a flow control valve and a double flow valve, thereby controlling the flow rate of the heating medium. (Kamimura, M.)

  19. Diode Laser Pumped Alkali Vapor Lasers with Exciplex-Assisted Absorption

    Science.gov (United States)

    2013-05-14

    gas pressure in the discharge cell was measured by a capacitance manometer (MKS Baratron). Tunable radiation with spectral bandwidth of 0 .3 cm·1...of low pressure Rb and Cs vapors from ground states and by low pressure Ar* and Kr* from metastable states. Exposed and developed PTR glass with an...provides efficient absorption of radiation by low pressure Rb and Cs vapors from ground states and by low pressure Ar* and Kr* from metastable states. The

  20. 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

  1. Nocturnal Hypertension and Attenuated Nocturnal Blood Pressure Dipping is Common in Pediatric Lupus [version 2; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    J. Fallon Campbell

    2015-11-01

    Full Text Available Hypertension is an important manifestation of systemic lupus erythematosus (SLE but reports of prevalence vary between 20-70% in published reports of adult and pediatric patients. For both children and adults with SLE, the clinical diagnosis and management of hypertension has traditionally been based on guidelines developed for the general population. In clinical trials, the criteria used for defining participants with hypertension are mostly undefined. As a first step towards formally assessing the blood pressure (BP patterns of children diagnosed with SLE, 24-hr ambulatory BP monitoring data was analyzed on clinic patients who presented with prehypertension or stage I hypertension. In this pediatric SLE cohort (n=10, 20% met daytime criteria for a diagnosis of hypertension. Patterns of BP elevation varied widely with white coat, masked, isolated systolic, and diastolic nocturnal hypertension all identified. Nocturnal hypertension was detected in 60% and attenuated nocturnal BP dipping in 90% of both hypertensive and normotensive SLE patients. In SLE patients, the median nighttime systolic and diastolic loads were 25% and 15.5% compared with median daily loads of 12.5% and 11.5%. Daytime and nighttime systolic and diastolic BP load and nocturnal dipping was compared to a control population consisting of 85 non-SLE patients under 21 years old with prehypertension or stage 1 hypertension presenting to hypertension clinic. Median systolic BP dipped 5.3 mmHg in SLE patients compared to 11.9 mmHg in non-lupus (p-value = 0.001. Median diastolic BP dipped 12.9 mmHg versus 18.5 mmHg in non-lupus (p-value = 0.003. Patterns of BP dysregulation in pediatric SLE merit further exploration. Children with or without SLE displaying prehypertensive or stage 1 casual BP measurements had similar rates of hypertension by ambulatory BP monitoring. However, regardless of BP diagnosis, and independent of kidney involvement, there was an increased proportion with

  2. 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

  3. Steam regulation for 5 MW back-pressure units when a failure occurs in the Los Humeros, Pue., field, Mexico; Regulacion del vapor en caso de falla a unidades a contrapresion de 5 MW en el campo de Los Humeros, Pue., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Rosales Lopez, Cesar [Comision Federal de Electricidad, Puebla (Mexico)]. E-mail: cesar.rosales@cfe.gob.mx

    2006-07-15

    Four out of the seven back-pressure power units of 5 MW operating in the Los Humeros geothermal field, State of Puebla, Mexico, are fed by one steam pipe gathering the steam produced by nine wells. When a failure occurred in any of the units and the excedence valve had to be open to deviate the steam, a decrease in the steam flow for the remaining units was noted, along with lower electrical generation. The cause for that is analyzed and explained in this paper by comparing the interconnected steam supply system to an electric circuit. A way to maintain a uniform and continuous supply of steam in the Los Humeros field has been found. It was implemented several months ago and the problem has not reoccurred. [Spanish] Cuatro de las siete unidades de 5 MW a contrapresion que operan en el campo geotermico de Los Humeros, Puebla, son alimentadas por un solo vaporducto que reune el vapor de nueve pozos productores. Cuando ocurria una falla en alguna de estas unidades y se abria por completo la valvula de excedencia para desviar el vapor, se observaba una reduccion en el flujo de vapor que llegaba a las otras tres unidades, lo que a su vez ocasionaba que la generacion de electricidad se redujera notoriamente. En este trabajo se analiza y explica la causa de ello, mediante la comparacion de este sistema interconectado de suministro de vapor con un circuito electrico, y se explica la solucion que se encontro e implemento en el campo de Los Humeros para regular el suministro continuo y uniforme de vapor, con resultados satisfactorios a varios meses de su implementacion en las cuatro unidades interconectadas.

  4. 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

  5. Tolman's length and limiting supersaturation of vapor

    Science.gov (United States)

    Alekseechkin, Nikolay V.

    2018-01-01

    The classical Kelvin formula for the equilibrium vapor pressure over a droplet of radius R is extended to small radii and vapor non-ideality, from where the limiting supersaturation condition is obtained by relating the point R = 0 to the value of limiting (spinodal) supersaturation of vapor. The analysis of different dependences of the Tolman length on radius, δ (R) , obeying this condition suggests that (i) the value of δ (0) is positive and the function δ (R) decreases with increasing radius; (ii) the curvature effect (the dependence of surface tension on radius) in the nucleation region is determined by the value of δ (0) . At the same time, this effect is weakly sensitive to the form of the function δ (R) and insensitive to its asymptotic value δ∞ .

  6. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    International Nuclear Information System (INIS)

    Freud, Roy; Harari, Ronen; Sher, Eran

    2009-01-01

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux during the cooling

  7. Vapor concentration monitor

    Science.gov (United States)

    Bayly, John G.; Booth, Ronald J.

    1977-01-01

    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  8. Vapor-phase carbonylation of dimethoxymethane over H-Faujasite.

    Science.gov (United States)

    Celik, Fuat E; Kim, Tae-Jin; Bell, Alexis T

    2009-01-01

    Carbonylation gets a phase lift: The usual liquid-phase, high-pressure processes for carbonylating formaldehydes are avoided in a novel vapor-phase reaction. Using an acid zeolite (Faujasite) at near-atmospheric pressure dimethoxymethane (DMM; the dimethyl acetal of formaldehyde; see scheme) is carbonylated to produce methyl methoxyacetate (MMAc). This approach provides a new route to ethylene glycol under mild conditions.

  9. 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 well-known 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. In this experiment cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture). The main conclusion from the experimental study is that hydrodynamic effects may be very significant in any shock tube analyses, especially when multiple interactions are observed. A theoretical study was performed to check the possibility of vapor film squeezing (between a drop in film boiling and a surface) as a controlling mechanism for making liquid--liquid contact. Using experimental data, the film thickness was calculated and it was found to be too thick for any conceivable film rupture mechanism. It was suggested that the coalescence is a two-stage process, in which the controlling stage depends mainly on temperature and surface properties and can be described as the ability of cold liquid to spread on a hot surface

  10. Chemical reaction between water vapor and stressed glass

    Science.gov (United States)

    Soga, N.; Okamoto, T.; Hanada, T.; Kunugi, M.

    1979-01-01

    The crack velocity in soda-lime silicate glass was determined at room temperature at water-vapor pressures of 10 to 0.04 torr using the double torsion technique. A precracked glass specimen (70 x 16 x 1.6 mm) was placed in a vacuum chamber containing a four-point bending test apparatus. The plotted experimental results show that the crack propagation curve in water agrees fairly well with that of Wiederhorn (1967). Attention is given to the effect of water vapor pressure on crack velocity at K(I) = 550,000 N/m to the 3/2 power, with (Wiederhorn's data) or without N2 present. The plotted results reveal that the present crack velocity is about two orders of magnitude higher than that of Wiederhorn at high water-vapor conditions, but the difference decreases as the water-vapor concentration diminishes or the crack velocity slows down.

  11. Vaporization of irradiated droplets

    International Nuclear Information System (INIS)

    Armstrong, R.L.; O'Rourke, P.J.; Zardecki, A.

    1986-01-01

    The vaporization of a spherically symmetric liquid droplet subject to a high-intensity laser flux is investigated on the basis of a hydrodynamic description of the system composed of the vapor and ambient gas. In the limit of the convective vaporization, the boundary conditions at the fluid--gas interface are formulated by using the notion of a Knudsen layer in which translational equilibrium is established. This leads to approximate jump conditions at the interface. For homogeneous energy deposition, the hydrodynamic equations are solved numerically with the aid of the CON1D computer code (''CON1D: A computer program for calculating spherically symmetric droplet combustion,'' Los Alamos National Laboratory Report No. LA-10269-MS, December, 1984), based on the implict continuous--fluid Eulerian (ICE) [J. Comput. Phys. 8, 197 (1971)] and arbitrary Lagrangian--Eulerian (ALE) [J. Comput. Phys. 14, 1227 (1974)] numerical mehtods. The solutions exhibit the existence of two shock waves propagating in opposite directions with respect to the contact discontinuity surface that separates the ambient gas and vapor

  12. Vapor liquid fraction determination

    International Nuclear Information System (INIS)

    1980-01-01

    This invention describes a method of measuring liquid and vapor fractions in a non-homogeneous fluid flowing through an elongate conduit, such as may be required with boiling water, non-boiling turbulent flows, fluidized bed experiments, water-gas mixing analysis, and nuclear plant cooling. (UK)

  13. Heat of vaporization spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D. Jr.

    1979-03-01

    Multilayer desorption measurements of various substances adsorbed on a stainless-steel substrate are found to exhibit desorption profiles consistent with a zeroth-order desorption model. The singleness of the desorption transients together with their narrow peak widths makes the technique ideally suited for a heat of vaporization spectrometer for either substance analysis or identification.

  14. Heat of vaporization spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D. Jr.

    1978-01-01

    Multilayer desorption measurements of various substances adsorbed on a stainless steel substrate are found to exhibit desorption profiles consistent with a zeroth order desorption model. The singleness of the desorption transients together with their narrow peak widths makes the technique ideally suited for a heat of vaporization spectrometer for either substance analysis or identification.

  15. Analytical modeling of the subsurface volatile organic vapor concentration in vapor intrusion.

    Science.gov (United States)

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2014-01-01

    The inhalation of volatile and semi-volatile organic compounds that intrude from a subsurface contaminant source into indoor air has become the subject of health and safety concerns over the last twenty years. Building subslab and soil gas contaminant vapor concentration sampling have become integral parts of vapor intrusion field investigations. While numerical models can be of use in analyzing field data and in helping understand the subslab and soil gas vapor concentrations, they are not widely used due to the perceived effort in setting them up. In this manuscript, we present a new closed-form analytical expression describing subsurface contaminant vapor concentrations, including subslab vapor concentrations. The expression was derived using Schwarz-Christoffel mapping. Results from this analytical model match well the numerical modeling results. This manuscript also explores the relationship between subslab and exterior soil gas vapor concentrations, and offers insights on what parameters need to receive greater focus in field studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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)

  18. Recommended sublimation pressure and enthalpy of benzene

    Czech Academy of Sciences Publication Activity Database

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

    2014-01-01

    Roč. 68, Jan (2014), s. 40-47 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal-gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

  19. METEOROLOGICAL INFLUENCES ON VAPOR INCIDENTS IN THE 200 EAST and 200 WEST TANK FARMS FROM CY2001 THRU CY2004

    International Nuclear Information System (INIS)

    FAUROTE, J.M.

    2004-01-01

    Investigation into the meteorological influences on vapor incidents in the tank farms to determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases. Weather phenomena, specifically barometric pressure, and wind velocity and direction can potentially cause or exacerbate a vapor release within the farm systems

  20. 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.

  1. Constrained Vapor Bubble Experiment

    Science.gov (United States)

    Gokhale, Shripad; Plawsky, Joel; Wayner, Peter C., Jr.; Zheng, Ling; Wang, Ying-Xi

    2002-11-01

    Microgravity experiments on the Constrained Vapor Bubble Heat Exchanger, CVB, are being developed for the International Space Station. In particular, we present results of a precursory experimental and theoretical study of the vertical Constrained Vapor Bubble in the Earth's environment. A novel non-isothermal experimental setup was designed and built to study the transport processes in an ethanol/quartz vertical CVB system. Temperature profiles were measured using an in situ PC (personal computer)-based LabView data acquisition system via thermocouples. Film thickness profiles were measured using interferometry. A theoretical model was developed to predict the curvature profile of the stable film in the evaporator. The concept of the total amount of evaporation, which can be obtained directly by integrating the experimental temperature profile, was introduced. Experimentally measured curvature profiles are in good agreement with modeling results. For microgravity conditions, an analytical expression, which reveals an inherent relation between temperature and curvature profiles, was derived.

  2. Stratified vapor generator

    Science.gov (United States)

    Bharathan, Desikan [Lakewood, CO; Hassani, Vahab [Golden, CO

    2008-05-20

    A stratified vapor generator (110) comprises a first heating section (H.sub.1) and a second heating section (H.sub.2). The first and second heating sections (H.sub.1, H.sub.2) are arranged so that the inlet of the second heating section (H.sub.2) is operatively associated with the outlet of the first heating section (H.sub.1). A moisture separator (126) having a vapor outlet (164) and a liquid outlet (144) is operatively associated with the outlet (124) of the second heating section (H.sub.2). A cooling section (C.sub.1) is operatively associated with the liquid outlet (144) of the moisture separator (126) and includes an outlet that is operatively associated with the inlet of the second heating section (H.sub.2).

  3. 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

  4. Vaporization of fault water during seismic slip

    Science.gov (United States)

    Chen, Jianye; Niemeijer, André R.; Fokker, Peter A.

    2017-06-01

    Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.

  5. A numerical investigation of vapor intrusion--the dynamic response of contaminant vapors to rainfall events.

    Science.gov (United States)

    Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

    2012-10-15

    the vapor intrusion risk. In addition, soil organic carbon retarded the transport process, and damped the contaminant concentration fluctuations. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Headspace concentrations of explosive vapors in containers designed for canine testing and training: theory, experiment, and canine trials.

    Science.gov (United States)

    Lotspeich, Erica; Kitts, Kelley; Goodpaster, John

    2012-07-10

    It is a common misconception that the amount of explosive is the chief contributor to the quantity of vapor that is available to trained canines. In fact, this quantity (known as odor availability) depends not only on the amount of explosive material, but also the container volume, explosive vapor pressure and temperature. In order to better understand odor availability, headspace experiments were conducted and the results were compared to theory. The vapor-phase concentrations of three liquid explosives (nitromethane, nitroethane and nitropropane) were predicted using the Ideal Gas Law for containers of various volumes that are in use for canine testing. These predictions were verified through experiments that varied the amount of sample, the container size, and the temperature. These results demonstrated that the amount of sample that is needed to saturate different sized containers is small, predictable and agrees well with theory. In general, and as expected, once the headspace of a container is saturated, any subsequent increase in sample volume will not result in the release of more vapors. The ability of canines to recognize and alert to differing amounts of nitromethane has also been studied. In particular, it was found that the response of trained canines is independent of the amount of nitromethane present, provided it is a sufficient quantity to saturate the container in which it is held. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  7. Investigation of vapor film motion regularities at boiling liquids

    Directory of Open Access Journals (Sweden)

    Zeigarnik Y.U.

    2013-04-01

    Full Text Available The experimental investigation of the saturated Freon-113 and distilled water film boiling on spheres with different diameters at atmospheric pressure under conditions of free convection is executed. With high-speed video average thickness and cumulative distribution function of vapor film as a function of the angle was measured. It was found that with increasing the angle the average thickness of vapor film can change by different laws depending on diameter of the sphere and the temperature difference. It was found also that the increase in the average vapor film thickness with increasing angle is more connected with the increase of large components of cumulative distribution function. It also noted the presence of quasi-periodic pulsations of the vapor film thickness in the lower part, which eventually largely determine the behavior of the interface at large angles.

  8. Study of film boiling collapse behavior during vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; 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.)

  9. Warm Vapor Atom Interferometer

    Science.gov (United States)

    Biedermann, Grant; Wheeler, David; Jau, Yuan-Yu; McGuinness, Hayden

    2014-05-01

    We present a light pulse atom interferometer using room temperature rubidium vapor. Doppler sensitive stimulated Raman transitions forming the atom optical elements inherently select a cold velocity group for the interferometer. The interferometer is configured to be sensitive to accelerations. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  10. 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

  11. Melt-Vapor Phase Diagram of the Te-S System

    Science.gov (United States)

    Volodin, V. N.; Trebukhov, S. A.; Kenzhaliyev, B. K.; Nitsenko, A. V.; Burabaeva, N. M.

    2018-03-01

    The values of partial pressure of saturated vapor of the constituents of the Te-S system are determined from boiling points. The boundaries of the melt-vapor phase transition at atmospheric pressure and in vacuum of 2000 and 100 Pa are calculated on the basis of partial pressures. A phase diagram that includes vapor-liquid equilibrium fields whose boundaries allow us to assess the behavior of elements upon distillation fractioning is plotted. It is established that the separation of elements is possible at the first evaporation-condensation cycle. Complications can be caused by crystallization of a sulfur solid solution in tellurium.

  12. [Hypertrophy and coronary reserve].

    Science.gov (United States)

    Motz, W; Scheler, S

    2008-12-01

    Left ventricular hypertrophy represents the structural mechanism of adaptation of the left ventricle as the answer of a chronic pressure overload in arterial hypertension. Initially an increment in left ventricular wall thickness occurs. In this stadium of "concentric hypertrophy" LV systolic wall stress, LV ejection fraction and myocardial oxygen consumption per weight unit myocardium remain unchanged. In the further time course of disease LV dilatation will be present. In this phase of "excentric hypertrophy" LV systolic wall stress and myocardial oxygen consumption per weight unit myocardium rise and LV ejection fraction decreases. Patients with arterial hypertension frequently complain of angina pectoris. Angina pectoris and the positive exercise tolerance test or the positive myocardial scintigraphy are the consequence of the impaired coronary flow reserve. The coronary flow reserve is diminished due to structural and functional changes of the coronary circulation. ACE-inhibitors and AT1-receptor blockers cause a significant improvement of coronary flow reserve and regression of both left ventricular hypertrophy and myocardial fibrosis.

  13. Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential

    Science.gov (United States)

    Keddy, Chris P.

    2012-01-01

    Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE.

  14. Steady State Vapor Bubble in Pool Boiling.

    Science.gov (United States)

    Zou, An; Chanana, Ashish; Agrawal, Amit; Wayner, Peter C; Maroo, Shalabh C

    2016-02-03

    Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source. The stability of the bubble allows us to measure the contact-angle and perform in-situ imaging of the contact-line region and the microlayer, on hydrophilic and hydrophobic surfaces and in both degassed and regular (with dissolved air) water. The early growth stage of vapor bubble in degassed water shows a completely wetted bubble base with the microlayer, and the bubble does not depart from the surface due to reduced liquid pressure in the microlayer. Using experimental data and numerical simulations, we obtain permissible range of maximum heat transfer coefficient possible in nucleate boiling and the width of the evaporating layer in the contact-line region. This technique of creating and measuring fundamental characteristics of a stable vapor bubble will facilitate rational design of nanostructures for boiling enhancement and advance thermal management in electronics.

  15. Modeling of vapor-liquid-liquid equilibria in binary mixtures

    NARCIS (Netherlands)

    Tzabar, Nir; ter Brake, Hermanus J.M.

    2016-01-01

    Vapor compression and Joule–Thomson (JT) cycles provide cooling power at the boiling temperatures of the refrigerants. Maintaining a fixed pressure in the evaporator allows for a stable cooling temperature at the boiling point of a pure refrigerant. In these coolers enhanced cooling power can be

  16. Quantitative Infrared Spectra of Vapor Phase Chemical Agents

    Energy Technology Data Exchange (ETDEWEB)

    Sharpe, Steven W.; Johnson, Timothy J.; Chu, P M.; Kleimeyer, J; Rowland, Brad; Gardner, Patrick J.

    2003-04-21

    Quantitative high resolution (0.1 cm -1) infrared spectra have been acquired for a number of pressure broadened (101.3 KPa N2), vapor phase chemicals including: Sarin (GB), Soman (GD), Tabun (GA), Cyclosarin (GF), VX, nitrogen mustard (HN3), sulfur mustard (HD) and Lewisite (L).

  17. A level set method for vapor bubble dynamics

    NARCIS (Netherlands)

    Can, E.; Prosperetti, Andrea

    2012-01-01

    This paper describes a finite-difference computational method suitable for the simulation of vapor–liquid (or gas–liquid) flows in which the dynamical effects of the vapor can be approximated by a time-dependent, spatially uniform pressure acting on the interface. In such flows it is not necessary

  18. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

    2009-04-15

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

  19. Shoot water relations of mature black spruce families displaying a genotype × environment interaction in growth rate. III. Diurnal patterns as influenced by vapor pressure deficit and internal water status

    Science.gov (United States)

    John E. Major; Kurt H. Johnsen

    2001-01-01

    Pressure­volume curves were constructed and shoot water potentials measured for +20-year-old black spruce (Picea mariana (Mill.) BSP) trees from four full-sib families growing on a moist site and a dry site at the Petawawa Research Forest, Ontario, to determine whether differences in diurnal water relations traits were related to productivity. To...

  20. 33 CFR 154.828 - Vapor recovery and vapor destruction units.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vapor recovery and vapor... SECURITY (CONTINUED) POLLUTION FACILITIES TRANSFERRING OIL OR HAZARDOUS MATERIAL IN BULK Vapor Control Systems § 154.828 Vapor recovery and vapor destruction units. (a) The inlet to a vapor recovery unit which...

  1. A Citizen's Guide to Vapor Intrusion Mitigation

    Science.gov (United States)

    This guide describes how vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings.Vapors primarily enter through openings in the building foundation or basement walls.

  2. Study of Lithium Vapor Flow In a Detached Divertor using DSMC code

    Science.gov (United States)

    Emdee, Eric; Schwartz, Jacob; Goldston, Robert; Jaworski, Michael

    2017-10-01

    A detached divertor is predicted to be necessary to handle the heat fluxes of a demonstration fusion power plant. The lithium vapor box divertor has poloidal baffles to form distinct chambers and contains dense lithium vapor to cause detachment. These chambers would be differentially pumped via condensation, resulting in flow at Knudsen numbers 0.01-0.5 and densities 1019-1023m-3. This divertor geometry is predicted to handle the estimated heat flux while also localizing the vapor in the divertor. We provide a simulation of the divertor's lithium vapor flow using the SPARTA Direct Simulation Monte Carlo (DSMC) code. Lithium mass flow, vapor pressures, and temperatures within each chamber are given. Preliminary simulations of a vapor box divertor similarity experiment are within 30% of an ideal-gas choked nozzle flow calculation. This work supported by DOE Contract No. DE-AC02-09CH11466.

  3. 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..

  4. Passive vapor extraction feasibility study

    International Nuclear Information System (INIS)

    Rohay, V.J.

    1994-01-01

    Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft 3 /min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft 3 /min air flow rates, passive vapor extraction is more cost effective below 100 ppm

  5. Phase equilibrium liquid-vapor in three-component system UF6-IF5-BrF3 at complete mutual components solubility

    OpenAIRE

    Zherin, Ivan Ignatyevich; Usov, V. F.; Ostvald, R. V.; Shagalov, V. V.; Gayday, I. V.; Tyulyubaev, Z. M.

    2007-01-01

    The results of studying phase equilibrium liquid-vapor at 353,15 K in the system of uranium hexafluoride, iodine pentafluoride, bromine trifluoride have been presented. The dependences of saturated vapor pressure on condensed phase composition, the results of analysis of studied system deviation from error-free behavior, the data on equilibrium vapor phase are given

  6. 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.

  7. High-energy components of 'designer gasoline and designer diesel fuel' I. Heat capacities, enthalpy increments, vapor pressures, critical properties, and derived thermodynamic functions for bicyclopentyl between the T=(10 and 600) K

    International Nuclear Information System (INIS)

    Chirico, R.D.; Steele, W.V.

    2004-01-01

    Measurements leading to the calculation of the standard thermodynamic properties for gaseous bicyclopentyl (Chemicals Abstracts registry number [1636-39-1]) are reported. Experimental methods include adiabatic heat-capacity calorimetry, comparative ebulliometry, and differential-scanning calorimetry (d.s.c.). The critical temperature was determined by d.s.c. and the critical pressure and critical density were estimated. Standard molar entropies, standard molar enthalpies, and standard molar Gibbs free energies of formation are reported at selected temperatures between T=(298.15 and 600) K. Formation properties were calculated with a literature value for the enthalpy of combustion in the liquid phase. All results are compared with available literature values

  8. Dimers in nucleating vapors

    Science.gov (United States)

    Lushnikov, A. A.; Kulmala, M.

    1998-09-01

    The dimer stage of nucleation may affect considerably the rate of the nucleation process at high supersaturation of the nucleating vapor. Assuming that the dimer formation limits the nucleation rate, the kinetics of the particle formation-growth process is studied starting with the definition of dimers as bound states of two associating molecules. The partition function of dimer states is calculated by summing the Boltzmann factor over all classical bound states, and the equilibrium population of dimers is found for two types of intermolecular forces: the Lennard-Jones (LJ) and rectangular well+hard core (RW) potentials. The principle of detailed balance is used for calculating the evaporation rate of dimers. The kinetics of the particle formation-growth process is then investigated under the assumption that the trimers are stable with respect to evaporation and that the condensation rate is a power function of the particle mass. If the power exponent λ=n/(n+1) (n is a non-negative integer), the kinetics of the process is described by a finite set of moments of particle mass distribution. When the characteristic time of the particle formation by nucleation is much shorter than that of the condensational growth, n+2 universal functions of a nondimensional time define the kinetic process. These functions are calculated for λ=2/3 (gas-to-particle conversion in the free molecular regime) and λ=1/2 (formation of islands on surfaces).

  9. Soil Vapor Extraction Implementation Experiences

    Science.gov (United States)

    This issue paper identifies issues and summarizes experiences with soil vapor extraction (SVE) as a remedy for volatile organic compounds (VOCs) in soils. The issues presented here reflect discussions with over 30 Remedial Project Managers (RPMs)...

  10. Atmospheric pressure organometallic vapor-phase epitaxial growth of (Al/x/Ga/1-x/)0.51In0.49P (x from 0 to 1) using trimethylalkyls

    Science.gov (United States)

    Cao, D. S.; Kimball, A. W.; Stringfellow, G. B.

    1990-01-01

    This paper describes growth of (Al/x/Ga/1-x)0.51In0.49P layers (with x from 0 to 1) lattice-matched to (001)-oriented GaAs substrates by atmospheric-pressure OMVPE, using trimethylindium, trimethylaluminum, and trimethylgallium and PH3 as source materials in a horizontal reactor. Excellent surface morphologies were obtained over the entire range of Al compositions at a growth temperature of 680 C. Photoluminescence (PL) was observed for all samples with x values not below 0.52, with PL peak energies as high as 2.212 eV. The PL FWHM for Ga(0.51)In(0.49)P was 7.2 meV at 10 K and 35 meV at 300 K. At 10 K, the PL intensity was nearly a constant over the composition range from x = 0 to 0.52.

  11. Digestibilidade do bagaço de cana-de-açúcar tratado com reagentes químicos e pressão de vapor Digestibility of sugar cane bagasse treated with chemical reagents and steam pressure

    Directory of Open Access Journals (Sweden)

    Ricardo Pereira Manzano

    2000-08-01

    Full Text Available Com o objetivo de elevar a digestibilidade do bagaço de cana-de-açúcar, este resíduo agro-industrial foi tratado com inúmeros reagentes químicos acompanhados ou não de tratamento físico. Após ensaios preliminares, nos quais diversos agentes deslignificantes foram avaliados, dez tratamentos foram selecionados para serem melhor estudados em ensaios de digestibilidade in vitro da matéria seca e da matéria orgânica. Em seguida, para o ensaio de digestibilidade in vivo, foram feitas quatro dietas à base de: 1 - Bagaço auto-hidrolisado (BAH, pressão de 17 kgf/cm² por 5 min; 2 - Bagaço tratado com 4% Na2S + 6% NaOH, pressão de 12 kgf/cm² por 8 min; 3 - Bagaço tratado com 2% Na2S + 3% NaOH, pressão de 12 kgf/cm² por 8 min; e 4 - Bagaço tratado com 9% H2O2 + 7% NaOH, a 70ºC por 8 min. Bagaço tratado com 4% Na2S + 6% NaOH e submetido a 12 kgf/cm² de pressão apresentou os melhores coeficientes de digestibilidade da matéria seca, matéria orgânica, fibra em detergente neutro e fibra em detergente ácido e o maior valor de nutrientes digestíveis totais. Em seguida, o bagaço tratado com 9% H2O2 + 7% NaOH a 70ºC por 8 min apresentou os melhores resultados. Piores resultados foram observados para o bagaço hidrolizado. A melhor digestibilidade de algumas das dietas, particularmente das frações fibrosas, sugere a exiqüibilidade do emprego de menores quantidades de alimento concentrado em dietas à base de bagaço de cana tratado química/fisicamente.In order to increase the sugar cane bagasse digestibility, this agricultural by-product was treated with several chemical reagents with or without physical treatment. After preliminary evaluation, where several delignificant agents were evaluated, ten treatments were selected for more detailed in vitro dry and organic matter disappearance trials. Then, for the in vivo digestibility trial, four sugar cane bagasse based diets were made: 1 - Hydrolyzed sugar cane bagasse, pressure of

  12. Are uranium reserves adequate?

    International Nuclear Information System (INIS)

    Anon.

    2006-01-01

    Against a backdrop of growing concerns about global warming and geopolitical pressures on fossil energies, especially natural gas and oil, interest in nuclear power has revived considerably. Conscious of its addiction to oil and reeling from a series of gigantic blackouts, the United States, in the words of its president, must 'aggressively move forward with the construction of nuclear power plants'. Some European countries have approved new power plant construction (Finland and France), while the more reserved ones (Belgium, Germany and Sweden) have begun to show a change in attitude. Asia, meanwhile, is host to the planet's largest number of potential nuclear construction projects in this first half of the 21. century. All these signs point to a sharp rise in uranium consumption, the basic fuel for these plants. But are there enough resources to support a nuclear revival on a planetary scale? The publication of the Red Book on uranium in late May 2006 was an opportunity for Thierry Dujardin, Deputy Director of Science and Development at the OECD's Nuclear Energy Agency, to take stock of resources. He gives his opinion in this paper

  13. Acoustic wave propagation in bubbly flow with gas, vapor or their mixtures.

    Science.gov (United States)

    Zhang, Yuning; Guo, Zhongyu; Gao, Yuhang; Du, Xiaoze

    2018-01-01

    Presence of bubbles in liquids could significantly alter the acoustic waves in terms of wave speed and attenuation. In the present paper, acoustic wave propagation in bubbly flows with gas, vapor and gas/vapor mixtures is theoretically investigated in a wide range of parameters (including frequency, bubble radius, void fraction, and vapor mass fraction). Our finding reveals two types of wave propagation behavior depending on the vapor mass fraction. Furthermore, the minimum wave speed (required for the closure of cavitation modelling in the sonochemical reactor design) is analyzed and the influences of paramount parameters on it are quantitatively discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Responses of epidermal cell turgor pressure and photosynthetic activity of leaves of the atmospheric epiphyte Tillandsia usneoides (Bromeliaceae) after exposure to high humidity.

    Science.gov (United States)

    Martin, Craig E; Rux, Guido; Herppich, Werner B

    2013-01-01

    It has been well-established that many epiphytic bromeliads of the atmospheric-type morphology, i.e., with leaf surfaces completely covered by large, overlapping, multicellular trichomes, are capable of absorbing water vapor from the atmosphere when air humidity increases. It is much less clear, however, whether this absorption of water vapor can hydrate the living cells of the leaves and, as a consequence, enhance physiological processes in such cells. The goal of this research was to determine if the absorption of atmospheric water vapor by the atmospheric epiphyte Tillandsia usneoides results in an increase in turgor pressure in leaf epidermal cells that subtend the large trichomes, and, by using chlorophyll fluorescence techniques, to determine if the absorption of atmospheric water vapor by leaves of this epiphyte results in increased photosynthetic activity. Results of measurements on living cells of attached leaves of this epiphytic bromeliad, using a pressure probe and of whole-shoot fluorescence imaging analyses clearly illustrated that the turgor pressure of leaf epidermal cells did not increase, and the photosynthetic activity of leaves did not increase, following exposure of the leaves to high humidity air. These results experimentally demonstrate, for the first time, that the absorption of water vapor following increases in atmospheric humidity in atmospheric epiphytic bromeliads is mostly likely a physical phenomenon resulting from hydration of non-living leaf structures, e.g., trichomes, and has no physiological significance for the plant's living tissues. Copyright © 2012 Elsevier GmbH. All rights reserved.

  15. Development of lithium vapor injector for boundary control

    International Nuclear Information System (INIS)

    Tsuchiya, Hayato; Hirooka, Yoshi; Ashikawa, Naoko; Chung, Kyu-Sun; Masuzaki, Suguru; Nagayama, Yoshio

    2010-01-01

    A lithium (Li) vapor injector for boundary control has been developed. A diverter covered with lithium is expected to reduce particle recycling. Recycling reduction is considered to be one of the triggers for the L-H transition. In this paper, the method of lithium dispersion is investigated under the assumption that the experiment is carried out in the Large Helical Device in National Institute for fusion Science, Japan (LHD). A performance test is performed on a prototype of the vapor injector. The amount of injected lithium was approximately 1% of the value expected from the vapor pressure data, due to the generation of lithium oxide. It is also found that nozzle temperature is quite important to suppress the Li dispersion.

  16. Growths of indium gallium nitride nanowires by plasma-assisted chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Wei-Che [Department of Chemical Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Hong, Franklin Chau-Nan, E-mail: hong@mail.ncku.edu.tw [Department of Chemical Engineering, National Cheng Kung University, 1 University Road, Tainan 701, Taiwan (China); Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China)

    2014-11-03

    InGaN nanowires (NWs) were grown on Si(100) at 700 °C using Au catalyst in a plasma-assisted chemical vapor deposition reactor. As the indium vapor pressure was low around 16 mPa during the growths, only the curved GaN NWs could be grown containing indium impurities. By increasing the indium vapor pressure to 53 mPa during the growths, InGaN NWs were transformed to less curved NWs with a broad distribution of NW diameters from 20 to 90 nm. The room temperature photoluminescence of InGaN NWs grown at a high indium vapor pressure showed a broad emission peak at 417 nm, corresponding to an average of 14.5% indium composition in the NWs, with a large full-width at half maximum of 77 nm. Transmission electron microscopy characterization of InGaN NWs showed that the growth orientation was along [100] for the low indium vapor pressure growths and was transformed to along [001] for the high indium vapor pressure growths. - Highlights: • High-quality single-crystalline InGaN nanowires were synthesized. • The indium content of InGaN nanowires grown at 700 °C did not exceed 15%. • A small amount of indium added into the nanowires induced stacking faults.

  17. High-pressure liquid chromatography with direct injection of gas sample.

    Science.gov (United States)

    Astanin, Anton I; Baram, Grigory I

    2017-06-09

    The conventional method of using liquid chromatography to determine the composition of a gaseous mixture entails dissolving vapors in a suitable solvent, then obtaining a chromatograph of the resulting solution. We studied the direct introduction of a gaseous sample into a C18 reversed-phase column, followed by separation of the components by HPLC with UV detection. Since the chromatography was performed at high pressure, vapors readily dissolved in the eluent and the substances separated in the column as effectively as in liquid samples. Samples were injected into the column in two ways: a) through the valve without a flow stop; b) after stopping the flow and relieving all pressure. We showed that an injectable gas volume could reach 70% of column dead volume. When an injected gaseous sample volume was less than 10% of the column dead volume, the resulting peaks were symmetrical and the column efficiency was high. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. 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

  19. PREVENTION AND CONTROL OF DIMETHYLAMINE VAPORS EMISSION: HERBICIDE PRODUCTION PLANT

    Directory of Open Access Journals (Sweden)

    Zorana Arsenijević

    2008-11-01

    Full Text Available The widely used herbicide, dimethylamine salt of 2,4-dichlorophenoxy acetic acid (2,4-D-DMA, is usually prepared by mixing a dimethylamine (DMA aqueous solution with a solid 2,4-dichlorophenoxy acetic acid (2,4-D. The vapors of the both, reactants and products, are potentially hazardous for the environment. The contribution of DMA vapors in overall pollution from this process is most significant, concerning vapor pressures data of these pollutants. Therefore, the control of the air pollution in the manufacture and handling of methylamines is very important. Within this paper, the optimal air pollution control system in preparation of 2,4-D-DMA was developed for the pesticides manufacturing industry. This study employed the simple pollution prevention concept to reduce the emission of DMA vapors at the source. The investigations were performed on the pilot plant scale. To reduce the emission of DMA vapors, the effluent gases from the herbicide preparation zone were passed through the packed bed scrubber (water - scrubbing medium, and the catalytic reactor in sequence. The end result is a substantially improved air quality in the working area, as well as in the urbanized areas located near the chemical plant.

  20. Studies of interfaces and vapors with Optical Second Harmonic Generation

    Energy Technology Data Exchange (ETDEWEB)

    Mullin, Christopher Shane [Lawrence Berkeley Lab., CA (United States); California Univ., Berkeley, CA (United States). Dept. of Physics

    1993-12-01

    Optical Second Harmonic Generation (SHG) has been applied to the study of soap-like molecules adsorbed to the water-air interface. By calibrating the signal from a soluble monolayer with that of an insoluble homolog, absolute measurements of the surface density could be obtained and related to the bulk concentration and surface tension. We could then demonstrate that the soluble surfactant forms a single monolayer at the interface. Furthermore, it deviates significantly from the ideal case in that its activity coefficients are far from 1, yet those coefficients remain constant over a broad range of surface pressures. We present evidence of a first-order phase transition taking place during the adsorption of this soluble monolayer. We consider the effects of the non-ideal behavior and the phase transition on the microscopic model of adsorption, and formulate an alternative to the Langmuir picture of adsorption which is just as simple, yet it can more easily allow for non-ideal behavior. The second half of this thesis considers the problem of SHG in bulk metal vapors. The symmetry of the vapor forbids SHG, yet it has been observed. We consider several models whereby the symmetry of the vapor is broken by the presence of the laser and compare their predictions to new observations we have made using a few-picosecond laser pulse. The two-lobed output beam profile shows that it is the vapor-plus-beam combination whose symmetry is important. The dependence on vapor pressure demonstrates the coherent nature of the radiation, while the dependence on buffer gas pressure hints at a change of the symmetry in time. The time-dependence is measured directly with a preliminary pump-probe measurement. The magnitude and intensity dependence of the signal are also measured. All but one of the models are eliminated by this comparison.

  1. Quantification of vapor intrusion pathways into a slab-on-ground building under varying environmental conditions.

    Science.gov (United States)

    Patterson, Bradley M; Davis, Greg B

    2009-02-01

    Potential hydrocarbon-vapor intrusion pathways into a building through a concrete slab-on-ground were investigated and quantified under a variety of environmental conditions to elucidate the potential mechanisms for indoor air contamination. Vapor discharge from the uncovered open ground soil adjacent to the building and subsequent advection into the building was unlikely due to the low soil-gas concentrations at the edge of the building as a result of aerobic biodegradation of hydrocarbon vapors. When the building's interior was under ambient pressure, a flux of vapors into the building due to molecular diffusion of vapors through the building's concrete slab (cyclohexane 11 and methylcyclohexane 31 mg m(-2) concrete slab day(-1)) and short-term (up to 8 h) cyclical pressure-driven advection of vapors through an artificial crack (cyclohexane 4.2 x 10(3) and methylcyclohexane 1.2 x 10(4) mg m(-2) cracks day(-1)) was observed. The average subslab vapor concentration under the center of the building was 25,000 microg L(-1). Based on the measured building's interiorvapor concentrations and the building's air exchange rate of 0.66 h(-1), diffusion of vapors through the concrete slab was the dominantvapor intrusion pathway and cyclical pressure exchanges resulted in a near zero advective flux. When the building's interior was under a reduced pressure (-12 Pa), advective transport through cracks or gaps in the concrete slab (cyclohexane 340 and methylcyclohexane 1100 mg m(-2) cracks day(-1)) was the dominant vapor intrusion pathway.

  2. Low temperature synthesis of Zn nanowires by physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Philipp; Kast, Michael; Brueckl, Hubert [Austrian Research Centers GmbH ARC, Nano- Systemtechnologies, Donau-City-Strasse 1, A-1220 Wien (Austria)

    2007-07-01

    We demonstrate catalytic growth of zinc nanowires by physical vapor deposition at modest temperatures of 125-175 C on various substrates. In contrast to conventional approaches using tube furnaces our home-built growth system allows to control the vapor sources and the substrate temperature separately. The silicon substrates were sputter coated with a thin gold layer as metal catalyst. The samples were heated to the growth temperature and subsequently exposed to the zinc vapor at high vacuum conditions. The work pressure was adjusted by the partial pressure of oxygen or argon flow gas. Scanning electron microscopy and atomic force microscopy characterizations revealed that the nanowires exhibit straight, uniform morphology and have diameters in the range of 50-350 nm and lengths up to 70 {mu}m. The Zn nanowires grow independently of the substrates crystal orientation via a catalytic vapor-solid growth mechanism. Since no nanowire formation was observed without gold coating, we expect that the onedimensional growth is initiated by a surface reactive Au seed. ZnO nanowires can be produced in the same preparation chamber by oxidation at 500 C in 1atm (80% Ar, 20% O{sub 2}) for 1 hour. ZnO is highly attractive for sensor applications.

  3. Overview of experimental studies on vapor explosions

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Yamano, Norihiro; Maruyama, Yu; Kudo, Tamotsu; Sugimoto, Jun

    1994-12-01

    Experimental studies of vapor explosions were overviewed and currently available knowledge was summarized with emphasis on the large scale experiments. Since 1970s, quite a few large scale experiments have been performed, which have included several types such as pin geometry experiments simulating the early stages of severe accidents in nuclear reactors, and melt-coolant interaction experiments with drop/jet geometry or stratified geometry simulating the phenomena expected to take place after a large scale core melt-down. According to previous experimental results, following facts are clarified ; spontaneous explosions are not likely with saturated coolant and/or with high pressures ; the energy conversion ratio in large scale systems is in the range 0.1∼several percents ; if the coolant is sodium generally benign interaction is expected compared with the case of water coolant ; etc. Recently, accompanied with the development of numerical simulation codes for vapor explosions, considerable efforts are devoted into premixing experiments and one dimensional geometry experiments oriented to provide data for the comparison with numerical simulations. (author) 87 refs

  4. Liquid-vapor rectilinear diameter revisited

    Science.gov (United States)

    Garrabos, Y.; Lecoutre, C.; Marre, S.; Beysens, D.; Hahn, I.

    2018-02-01

    In the modern theory of critical phenomena, the liquid-vapor density diameter in simple fluids is generally expected to deviate from a rectilinear law approaching the critical point. However, by performing precise scannerlike optical measurements of the position of the SF6 liquid-vapor meniscus, in an approach much closer to criticality in temperature and density than earlier measurements, no deviation from a rectilinear diameter can be detected. The observed meniscus position from far (10 K ) to extremely close (1 mK ) to the critical temperature is analyzed using recent theoretical models to predict the complete scaling consequences of a fluid asymmetry. The temperature dependence of the meniscus position appears consistent with the law of rectilinear diameter. The apparent absence of the critical hook in SF6 therefore seemingly rules out the need for the pressure scaling field contribution in the complete scaling theoretical framework in this SF6 analysis. More generally, this work suggests a way to clarify the experimental ambiguities in the simple fluids for the near-critical singularities in the density diameter.

  5. Pressure suppression device

    International Nuclear Information System (INIS)

    Mizumachi, Wataru; Fukuda, Akira; Kitaguchi, Hidemi; Shimizu, Toshiaki.

    1976-01-01

    Object: To relieve and absorb impact wave vibrations caused by steam and non-condensed gases releasing into the pressure suppression chamber at the time of an accident. Structure: The reactor container is filled with inert gases. A safety valve attached main steam pipe is provided to permit the excessive steam to escape, the valve being communicated with the pressure suppression chamber through an exhaust pipe. In the pressure suppression chamber, a doughnut-like cylindrical outer wall is filled at its bottom with pool water to condense the high temperature vapor released through the exhaust pipe. A head portion of a vent tube which leads the exhaust pipe is positioned at the top, and a down comer and an exhaust vent tube are locked by means of steady rests. At the bottom is mounted a pressure adsorber device which adsorbs a pressure from the pool water. (Kamimura, M.)

  6. Pressure suppression device

    International Nuclear Information System (INIS)

    Ichiki, Tadaharu; Funahashi, Toshihiro.

    1976-01-01

    Purpose: To provide a structure which permits the absorption of shocks and vibratory load produced on the floor of a pressure suppression chamber due to nitrogen gas or the like discharged into pool water in the pressure suppression chamber at the time of a loss-of-coolant accident. Constitution: A pressure suppression chamber accommodating pool water is comprised of a bottom wall and side walls constructed of concrete on the inner side of a liner. By providing concrete on the bottom surface and side wall surfaces of a pressure suppression chamber, it is possible to prevent non-condensing gas and steam exhausted from the vent duct and exhaust duct of a main vapor escapement safety valve exhaust duct from exerting impact forces and vibratory forces upon the bottom and side surfaces of the pressure suppression chamber. (Horiuchi, T.)

  7. Vapor Explosions with Subcooled Freon

    International Nuclear Information System (INIS)

    Henry, R.E.; Fauske, Hans K.; McUmber, L.M.

    1976-01-01

    Explosive vapor formation accompanied by destructive shock waves, can be produced when two liquids, at much different temperatures, are brought into intimate contact. A proposed analytical model states that the interface temperature upon contact between the two liquid systems, gust be greater than or equal to the spontaneous nucleation temperature of that liquid-liquid system and that the thermal boundary layer must be sufficiently developed to support a critical size cavity. For time scales greater than 10-12 sec, the interface temperature upon contact of two semi-infinite masses, with constant thermal properties, can be related to the initial liquid temperatures. The spontaneous nucleation behavior at the interface can either be heterogeneous or homogeneous in nature. In either case, the critical size cavities, which initiate the vaporization process, are produced by local density fluctuations within the cold liquid. For homogeneous conditions, the two liquids present a well-wetted system and the vapor embryos are produced entirely within the cold liquid. For heterogeneous conditions, which result from poor, or imperfect wetting, at the liquid-liquid interface, the critical sized cavities are created at the interface at somewhat lower temperatures. A sequence of experiments, using Freon-22 and water, Freon-22 and mineral oil, and Freon-12 and mineral oil have been performed to test this spontaneous nucleation premise. For Freon-22 at its normal boiling point, the interface temperature of the water must be at least 77 deg. C before the interface temperature equals or exceeds the minimum homogeneous nucleation value of 54 deg. C and 84 deg. C before the interface temperature equals 60 deg. C where the homogeneous nucleation rate becomes truly explosive. The Freon-water test demonstrated explosive interactions for water temperatures considerably lower than this value and this was attributed to the heterogeneous nucleation characteristics of that particular system

  8. METEOROLOGICAL INFLUENCES ON VAPOR INCIDENTS IN THE 200 EAST & 200 WEST TANK FARMS FROM CY1995 TO CY2004

    Energy Technology Data Exchange (ETDEWEB)

    HOCKING, M.J.

    2005-01-31

    Revised for a more comprehensive overview of vapor incidents reported at the Hanford Tank Farms. Investigation into the meteorological influences on vapor incidents in the tank farm to determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases. Weather phenomena, specifically barometric pressure, and wind velocity and direction can potentially cause or exacerbate a vapor release within the farm systems. The purpose of this document is to gather and evaluate the meteorological and weather information for the Tank Farms Shift Log Vapor Incident entries and determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases such as propane. A part of the evaluation will be determining which of the incidents are related to actual ''intrusive'' work, and which are ''transient.'' Transient vapor incidents are herein defined as those vapors encountered during walkdowns, surveys, or other activities that did not require working directly with the tanks, pits, transfer lines, etc. Another part of the investigation will involve determining if there are barometric pressures or other weather related phenomena that might cause or contribute vapors being released when there are no ''intrusive'' activities. A final purpose is to evaluate whether there is any correlation between the 242-A Evaporator operations and Vapor Incidents entered on the Shift Log.

  9. METEOROLOGICAL INFLUENCES ON VAPOR INCIDENTS IN THE 200 EAST and 200 WEST TANK FARMS FROM CY1995 TO CY2004

    International Nuclear Information System (INIS)

    HOCKING, M.J.

    2005-01-01

    Revised for a more comprehensive overview of vapor incidents reported at the Hanford Tank Farms. Investigation into the meteorological influences on vapor incidents in the tank farm to determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases. Weather phenomena, specifically barometric pressure, and wind velocity and direction can potentially cause or exacerbate a vapor release within the farm systems. The purpose of this document is to gather and evaluate the meteorological and weather information for the Tank Farms Shift Log Vapor Incident entries and determine what, if any, meteorological influences contribute to the reporting of odors, smells, vapors, and other gases such as propane. A part of the evaluation will be determining which of the incidents are related to actual ''intrusive'' work, and which are ''transient.'' Transient vapor incidents are herein defined as those vapors encountered during walkdowns, surveys, or other activities that did not require working directly with the tanks, pits, transfer lines, etc. Another part of the investigation will involve determining if there are barometric pressures or other weather related phenomena that might cause or contribute vapors being released when there are no ''intrusive'' activities. A final purpose is to evaluate whether there is any correlation between the 242-A Evaporator operations and Vapor Incidents entered on the Shift Log

  10. Determination of Vaporization Properties and Volatile Hazardous Components Relevant to Kukersite Oil Shale Derived Fuel Oil Handling

    Directory of Open Access Journals (Sweden)

    Ada TRAUMANN

    2014-09-01

    Full Text Available The aim of this study was to investigate vaporization properties of shale fuel oil in relation to inhalation exposure. The shale fuel oil was obtained from kukersite oil shale. The shale oil and its light fraction (5 % of the total fuel oil were characterized by vapor pressure curve, molecular weight distribution, elemental composition and functional groups based on FTIR spectra. The rate of vaporization from the total fuel oil at different temperatures was monitored as a function of time using thermogravimetric analysis (TGA. It is shown that despite its relatively low vapor pressure at room temperature a remarkable amount of oil vaporizes influencing air quality significantly. From the TGA data the changes in the vapor pressure during vaporization process were estimated. Although the shale fuel oil has a strong, unpleasant smell, the main hazards to workplace air quality depend on the vaporization rate of different toxic compounds, such as benzene, toluene, xylene or phenolic compounds. The presence of these hazardous substances in the vapor phase of shale fuel oil was monitored using headspace analysis coupled with selective ion monitoring (SIM and confirmed by the NIST Mass Spectral library and retention times of standards. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4549

  11. 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.

  12. 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)

  13. Stepwise Swelling of a Thin Film of Lamellae-Forming Poly(styrene-b-butadiene) in Cyclohexane Vapor

    DEFF Research Database (Denmark)

    Di, Zhenyu; Posselt, Dorthe; Smilgies, Detlef-M.

    2012-01-01

    We investigated the swelling of a thin film of lamellae-forming poly(styrene-b-butadiene) in cyclohexane vapor. The vapor pressure and thus the degree of swelling of the film are increased in a stepwise manner using a custom-built sample cell. The resulting structural changes during and after each...

  14. Rehabilitation and extension of the useful operating life of a high pressure casing of the 75 MW steam turbine of the thermoelectric power plant President Juarez in Rosarito, B.C.; Rehabilitacion y extension de vida util de una carcasa de alta presion de la turbina de vapor de 75 MW de la central termoelectrica Presidente Juarez en Rosarito, B.C.

    Energy Technology Data Exchange (ETDEWEB)

    Mazur C, Zdzislaw; Hernandez R, Alejandro; Luna R, Alberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Fernandez, Rafael; Nieblas, Enrique [Comision Federal de Electricidad, Rosarito, Baja California (Mexico)

    2004-07-01

    The effective operation of the steam turbines is important to the world industries, but as all machinery, it is necessary to constantly examine and give maintenance to this equipment with the purpose of producing better results. Yet, many steam turbines arrive at an operation period of 30 or 40 years, over their original design capacity. A factor like this, only augments the probabilities of future problems with the casings, such as: thermal fatigue fissures, deformation of the horizontal union and erosion problems in the low pressure housings. The deformation of the casing can affect its capacity to maintain aligned the stationary parts of the turbine, as a consequence, damages can appear in the fixed and rotary components by interference or friction. Also, the water induction can deform the casing to such a degree that, the alignment of the stationary parts is altered until it causes contact and friction between stationary and rotary parts. However, depending on the type and degree of the casing deformation, different methods of rehabilitation can be applied. The core goal is to recover the planarity of the union of the flanges, re-machining the plane of the flange of the upper and lower casing or, alternatively, to carry out a scraping by hand. [Spanish] El funcionamiento eficaz de las turbinas de vapor es importante para las industrias del mundo, pero como toda maquinaria, es necesario examinar y dar mantenimiento constantemente a este equipo con la finalidad de producir mejores resultados. Con todo, muchas turbinas de vapor llegan a un periodo de operacion de 30 o 40 anos, por encima de su capacidad de diseno original. Un factor como este, solo eleva las probabilidades de futuros problemas con las carcasas, tales como: fisuras por fatiga termica, deformacion de la union horizontal y problemas de erosion en las carcasas de baja presion. La deformacion de la carcasa puede afectar su capacidad para mantener alineadas las partes estacionarias de la turbina, como

  15. Chemical vapor deposited boron carbide

    International Nuclear Information System (INIS)

    Mackinnon, I.D.R.; Smith, K.L.

    1987-01-01

    Detailed analytical electron microscope (AEM) studies of yellow whiskers produced by chemical vapor deposition (CVD) show that two basic types of whiskers are produced at low temperatures (between 1200 0 C and 1400 0 C) and low boron to carbon gas ratios. Both whisker types show planar microstructures such as twin planes and stacking faults oriented parallel to, or at a rhombohedral angle to, the growth direction. For both whisker types, the presence of droplet-like terminations containing both Si and Ni indicate that the growth process during CVD is via a vapor-liquid-solid (VLS) mechanisms

  16. Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer

    Science.gov (United States)

    Schofield, J. T.; Mccleese, Daniel J.

    1988-01-01

    An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

  17. Recent advances towards a lithium vapor box divertor

    Directory of Open Access Journals (Sweden)

    R.J. Goldston

    2017-08-01

    Full Text Available Fusion power plants are likely to require near complete detachment of the divertor plasma from the divertor target plates, in order to have both acceptable heat flux at the target to avoid prompt damage and also acceptable plasma temperature at the target surface, to minimize long-term erosion. However hydrogenic and impurity puffing experiments show that detached operation leads easily to x-point MARFEs, impure plasmas, degradation in confinement, and lower helium pressure at the exhaust. The concept of the Lithium Vapor Box Divertor is to use local evaporation and strong differential pumping through condensation to localize low-Z gas-phase material that absorbs the plasma heat flux and so achieve detachment while avoiding these difficulties. The vapor localization has been confirmed using preliminary Navier–Stokes calculations. We use ADAS calculations of εcool, the plasma energy lost per injected lithium atom, to estimate the lithium vapor pressure, and so temperature, required for detachment, taking into account power balance. We also develop a simple model of detachment to evaluate the required upstream density, based on further taking into account dynamic pressure balance. A remarkable general result is found, not just for lithium-vapor-induced detachment, that the upstream density divided by the Greenwald-limit density scales as nup/nGW ∝ (P5/8/B3/8 Tdet1/2/(εcool+γTdet, with no explicit size scaling. Tdet is the temperature just before strong pressure loss, assumed to be ∼ ½ of the ionization potential of the dominant recycling species, and γ is the sheath heat transmission factor.

  18. Customer exposure to gasoline vapors during refueling at service stations.

    Science.gov (United States)

    Hakkola, M A; Saarinen, L H

    2000-09-01

    Gasoline is a volatile complex mixture of hydrocarbon compounds that is easily vaporized during handling under normal conditions. Modern reformulated gasoline also contains oxygenates to enhance octane number and reduce ambient pollution. This study measured the difference in the exposure of customers to gasoline and oxygenate vapors during refueling in service stations with and without vapor recovery systems. Field measurements were carried out at two self-service stations. One was equipped with Stage I and the other with Stage II vapor recovery systems. At Stage I stations there is vapor recovery only during delivery from road tanker, and at Stage II stations additional vapor recovery during refueling. The exposure of 20 customers was measured at both stations by collecting air samples from their breathing zone into charcoal tubes during refueling with 95-octane reformulated gasoline. Each sample represented two consecutive refuelings. The samples were analyzed in the laboratory by gas chromatography using mass-selective detection for vapor components. The Raid vapor pressure of gasoline was 70 kPa and an oxygen content 2 wt%. Oxygenated gasoline contained 7 percent methyl tert-butyl ether (MtBE) and 5 percent methyl tert-amyl ether (MtAE). The geometric mean concentrations of hydrocarbons (C3-C11) in the customers' breathing zone was 85 mg/m3 (range 2.5-531 mg/m3) at the Stage I service station and 18 mg/m3 (range service station. The geometric mean of the exposure of customers to MtBE during refueling at the Stage I service station was 15.3 mg/m3 (range 1.8-74 mg/m3), and at the Stage II service station 3.4 mg/m3 (range 0.2-16 mg/m3). The differences in exposure were statistically significant (p station. The measurements were done on consecutive days at the various service stations. The temperature ranged from 10 to 17 degrees C, and wind velocity was 2-4 m/s. The climatic conditions were very similar on the measurement days. Based on this study it was found

  19. Waste Tank Vapor Project: Tank vapor database development

    International Nuclear Information System (INIS)

    Seesing, P.R.; Birn, M.B.; Manke, K.L.

    1994-09-01

    The objective of the Tank Vapor Database (TVD) Development task in FY 1994 was to create a database to store, retrieve, and analyze data collected from the vapor phase of Hanford waste tanks. The data needed to be accessible over the Hanford Local Area Network to users at both Westinghouse Hanford Company (WHC) and Pacific Northwest Laboratory (PNL). The data were restricted to results published in cleared reports from the laboratories analyzing vapor samples. Emphasis was placed on ease of access and flexibility of data formatting and reporting mechanisms. Because of time and budget constraints, a Rapid Application Development strategy was adopted by the database development team. An extensive data modeling exercise was conducted to determine the scope of information contained in the database. a A SUN Sparcstation 1000 was procured as the database file server. A multi-user relational database management system, Sybase reg-sign, was chosen to provide the basic data storage and retrieval capabilities. Two packages were chosen for the user interface to the database: DataPrism reg-sign and Business Objects trademark. A prototype database was constructed to provide the Waste Tank Vapor Project's Toxicology task with summarized and detailed information presented at Vapor Conference 4 by WHC, PNL, Oak Ridge National Laboratory, and Oregon Graduate Institute. The prototype was used to develop a list of reported compounds, and the range of values for compounds reported by the analytical laboratories using different sample containers and analysis methodologies. The prototype allowed a panel of toxicology experts to identify carcinogens and compounds whose concentrations were within the reach of regulatory limits. The database and user documentation was made available for general access in September 1994

  20. 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.

  1. Cognitive reserve in aging.

    Science.gov (United States)

    Tucker, A M; Stern, Y

    2011-06-01

    Cognitive reserve explains why those with higher IQ, education, occupational attainment, or participation in leisure activities evidence less severe clinical or cognitive changes in the presence of age-related or Alzheimer's disease pathology. Specifically, the cognitive reserve hypothesis is that individual differences in how tasks are processed provide reserve against brain pathology. Cognitive reserve may allow for more flexible strategy usage, an ability thought to be captured by executive functions tasks. Additionally, cognitive reserve allows individuals greater neural efficiency, greater neural capacity, and the ability for compensation via the recruitment of additional brain regions. Taking cognitive reserve into account may allow for earlier detection and better characterization of age-related cognitive changes and Alzheimer's disease. Importantly, cognitive reserve is not fixed but continues to evolve across the lifespan. Thus, even late-stage interventions hold promise to boost cognitive reserve and thus reduce the prevalence of Alzheimer's disease and other age-related problems.

  2. Nonlinear dynamics of a vapor bubble expanding in a superheated region of finite size

    Energy Technology Data Exchange (ETDEWEB)

    Annenkova, E. A., E-mail: a-a-annenkova@yandex.ru [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Kreider, W. [Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States); Sapozhnikov, O. A. [Physics Faculty, Moscow State University, Leninskie Gory, 119991 Moscow (Russian Federation); Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, 1013 NE 40th St., Seattle, WA 98105 (United States)

    2015-10-28

    Growth of a vapor bubble in a superheated liquid is studied theoretically. Contrary to the typical situation of boiling, when bubbles grow in a uniformly heated liquid, here the superheated region is considered in the form of a millimeter-sized spherical hot spot. An initial micron-sized bubble is positioned at the hot spot center and a theoretical model is developed that is capable of studying bubble growth caused by vapor pressure inside the bubble and corresponding hydrodynamic and thermal processes in the surrounding liquid. Such a situation is relevant to the dynamics of vapor cavities that are created in soft biological tissue in the focal region of a high-intensity focused ultrasound beam with a shocked pressure waveform. Such beams are used in the recently proposed treatment called boiling histotripsy. Knowing the typical behavior of vapor cavities during boiling histotripsy could help to optimize the therapeutic procedure.

  3. Vaporization and thermodynamics of ceramics based on the La2O3-Y2O3-HfO2system studied by the high temperature mass spectrometric method.

    Science.gov (United States)

    Kablov, Eugene N; Stolyarova, Valentina L; Vorozhtcov, Viktor A; Lopatin, Sergey I; Fabrichnaya, Olga В; Ilatovskaya, Mariia O; Karachevtsev, Fedor N

    2018-02-27

    Materials based on the La 2 O 3 -Y 2 O 3 -HfO 2 system are promising for the production of highly refractory ceramics, e.g., thermal barrier coatings and molds for casting of elements of gas turbine engines. When these ceramics are synthesized or used at high temperatures, selective vaporization of components may take place, resulting in changes in the physicochemical The verties of the materials. Consequently, development of materials based on the La 2 O 3 -Y 2 O 3 -HfO 2 system requires information on vaporization in this system as well as on its thermodynamics, without which prediction and modeling of their physicochemical properties are impossible. Vaporization processes and thermodynamic properties in the La 2 O 3 -Y 2 O 3 -HfO 2 system were studied by the high temperature Knudsen effusion mass spectrometric method using a MS-1301 mass spectrometer. Electron ionization of vapor species was employed at an ionization energy of 25 eV. The samples under study and reference substances were vaporized from a tungsten twin effusion cell. At 2337 K the main vapor species over samples in the La 2 O 3 -Y 2 O 3 -HfO 2 system were shown to be LaO, YO and O. The partial pressures of the vapor species mentioned and the La 2 O 3 and Y 2 O 3 activities in the samples were obtained at 2337 K. The Gibbs energies of mixing and excess Gibbs energies were found in the solid solution of this system. Vaporization of ceramics based on the La 2 O 3 -Y 2 O 3 -HfO 2 system at 2337 K led to selective transition of La 2 O 3 and Y 2 O 3 to the gaseous phase, with the La 2 O 3 vaporization rate being higher than that of Y 2 O 3 . The directions of composition changes of samples due to their vaporization at 2337 K were determined. In the solid solution of this system negative deviations from ideal behavior were found. The ability to estimate the excess Gibbs energies in the solid solution of the La 2 O 3 -Y 2 O 3 -HfO 2 system by the Kohler method was shown. This article is protected by

  4. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  5. 46 CFR 154.554 - Cargo hose: Bursting pressure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo hose: Bursting pressure. 154.554 Section 154.554... Hose § 154.554 Cargo hose: Bursting pressure. Cargo hose that may be exposed to the pressure in the cargo tank, the cargo pump discharge, or the vapor compressor discharge must have a bursting pressure of...

  6. Graphene based piezoresistive pressure sensor

    NARCIS (Netherlands)

    Zhu, S.E.; Ghatkesar, M.K.; Zhang, C.; Janssen, G.C.A.M.

    2013-01-01

    We present a pressure sensor based on the piezoresistive effect of graphene. The sensor is a 100?nm thick, 280??m wide square silicon nitride membrane with graphene meander patterns located on the maximum strain area. The multilayer, polycrystalline graphene was obtained by chemical vapor

  7. Running on Empty? The Compensatory Reserve Index

    Science.gov (United States)

    2013-12-01

    and HR,31 more blood pressure oscillations,32 and greater vasoconstrictor reserve,33 compared with low-tolerant individuals. By leveraging recent... vasoconstrictor reserves. Clin Auton Res. 2012; 22:123Y130. 32. Rickards CA, Ryan KL, Cooke WH, Convertino VA. Tolerance to central hypovolemia: the

  8. Sensitivity of infrared water vapor analyzers to oxygen concentration and errors in stomatal conductance.

    Science.gov (United States)

    Bunce, James A

    2002-01-01

    Use of infrared analyzers to measure water vapor concentrations in photosynthesis systems is becoming common. It is known that sensitivity of infrared carbon dioxide and water vapor analyzers is affected by the oxygen concentration in the background gas, particularly for absolute analyzers, but the potential for large errors in estimates of stomatal conductance due to effects of oxygen concentration on the sensitivity of infrared water vapor analyzers is not widely recognized. This work tested three types of infrared water vapor analyzers for changes in sensitivity of infrared water vapor analyzers depending on the oxygen content of the background gas. It was found that changing from either 0 or 2% to 21% oxygen in nitrogen decreased the sensitivity to water vapor for all three types of infrared water vapor analyzers by about 4%. The change in sensitivity was linear with oxygen mole fraction. The resulting error in calculated stomatal conductance would depend strongly on the leaf to air vapor pressure difference and leaf temperature, and also on whether leaf temperature was directly measured or calculated from energy balance. Examples of measurements of gas exchange on soybean leaves under glasshouse conditions indicated that changing from 21% to 2% oxygen produced an artifactual apparent increase in stomatal conductance which averaged about 30%. Similar errors occurred for 'conductances' of wet filter paper. Such errors could affect inferences about the carbon dioxide dependence of the sensitivity of photosynthesis to oxygen.

  9. 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.

  10. 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

  11. Effects of mass transfer on damping mechanisms of vapor bubbles oscillating in liquids.

    Science.gov (United States)

    Zhang, Yuning; Gao, Yuhang; Guo, Zhongyu; Du, Xiaoze

    2018-01-01

    The damping mechanisms play an important role in the behavior of vapor bubbles. In the present paper, effects of mass transfer on the damping mechanisms of oscillating vapor bubbles in liquids are investigated within a wide range of parameter zone (e.g. in terms of frequency and bubble Péclet number). Results of the vapor bubbles are also compared with those of the gas bubbles. Our findings reveal that the damping mechanisms of vapor bubbles are significantly affected by the mass transfer especially in the regions with small and medium bubble Péclet number. Comparing with the gas bubbles, the contributions of the mass-transfer damping mechanism for the vapor bubble case are quite significant, being the dominant damping mechanism in a wide region. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Reid Vapor Pressure Regulation of Gasoline 1987-1990

    Science.gov (United States)

    1990-09-30

    programs with enforceable sanctions. In California, the one jurisdiction with a sustained history of rigorous volatility regulation, failure to follow... Architectura ; coatings ............ J t pc . ..... ...... ..... 4" pP .. ... Ak Fieet aiternative I~eis .................. . .. ....... 0 ................ J.I...183 from the EPA plan. Whether that position could be sustained if a Class C nonattainment state submitted a State Implementation Plan revision

  13. Isobaric (vapor + liquid) equilibria of the binary system maleic anhydride and diethyl phthalate at p = (2.67, 5.33, and 8.00) kPa

    Energy Technology Data Exchange (ETDEWEB)

    Xu Wei [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China); Liu Zhihua [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China); Tian Yiling [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China)]. E-mail: sdwfliu@yahoo.com.cn; Zhu Rongjiao [Department of Chemistry, Institute of Science, Tianjin University, Tianjin 300072 (China)

    2006-11-15

    Saturated vapor pressures of pure diethyl phthalate were measured with the ebulliometer. And isobaric (vapor + liquid) equilibrium data for the binary system (maleic anhydride + diethyl phthalate) at p = (2.67, 5.33, and 8.00) kPa were determined using the ebulliometric method. The parameters of the NRTL model for the binary system were obtained by calculating equilibrium compositions of the liquid and vapor phase with the experimental equilibrium temperatures, pressures and feed compositions. Moreover (vapor + liquid) equilibrium data for the binary system were predicted by use of the UNIFAC model. Predicted results were compared with those from the ebulliometric method, and showed good agreement.

  14. Latent fingermark development using low-vacuum vaporization of ninhydrin.

    Science.gov (United States)

    Chen, Chun-Chieh; Yang, Chao-Kai; Liao, Jeh-Shane; Wang, Sheng-Meng

    2015-12-01

    The vacuum technique is a method of vaporizing a solid material to its gas phase, helping deposit reagents gently on target surfaces to develop latent fingermarks. However, this application is rarely reported in the literature. In this study, a homemade fume hood with a built-in vacuum control system and programmable heating system designed by the Taiwan Criminal Investigation Bureau is introduced. Factors that affect the instrument's performance in developing fingermarks are discussed, including the quantity of chemicals for vaporization, heating program arrangement, and paper of different materials. The results show that fingermarks are effectively developed by vaporizing solid ninhydrin. This would be an alternative application in selecting a solvent-free method for protecting the environment and reducing health hazards in the lab. In terms of the heating program, the result indicates that under a low-vacuum condition (50 mTorr), 80-90 °C is a suitable temperature range for ninhydrin vaporization, allowing ninhydrin to be vaporized without bumping and waste. In terms of the performance on different material papers, this instrument demonstrates its capacity by developing latent fingermarks on thermal paper without discoloration or damaging the original writing, and the same results are also observed on Taiwan and United States banknotes. However, a coherent result could be hardly obtained using the same vaporization setting because different banknotes have their own surface features and water absorption ability or other unique factors may influence the effect of ninhydrin deposition. This study provides a reliable application for developing latent fingermarks without using solvents, and it is also expected to contribute to environmental protection along with the trend of green chemistry technology. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Vaporization of tungsten-metal in steam at high temperatures

    International Nuclear Information System (INIS)

    Greene, G.A.; Finfrock, C.C.

    2000-01-01

    The vaporization of tungsten from the APT spallation target dominates the radiological source term for unmitigated target overheating accidents. Chemical reactions of tungsten with steam which persist to tungsten temperatures as low as 800 C result in the formation of a hydrated tungsten-oxide which has a high vapor pressure and is readily convected in a flowing atmosphere. This low-temperature vaporization reaction essentially removes the oxide film that forms on the tungsten-metal surface as soon as it forms, leaving behind a fresh metallic surface for continued oxidation and vaporization. Experiments were conducted to measure the oxidative vaporization rates of tungsten in steam as part of the effort to quantify the MT radiological source term for severe target accidents. Tests were conducted with tungsten rods (1/8 inch diameter, six inches long) heated to temperatures from approximately 700 C to 1350 C in flowing steam which was superheated to 140 C. A total of 19 experiments was conducted. Fifteen tests were conducted by RF induction heating of single tungsten rods held vertical in a quartz glass retort. Four tests were conducted in a vertically-mounted tube furnace for the low temperature range of the test series. The aerosol which was generated and transported downstream from the tungsten rods was collected by passing the discharged steam through a condenser. This procedure insured total collection of the steam along with the aerosol from the vaporization of the rods. The results of these experiments revealed a threshold temperature for tungsten vaporization in steam. For the two tests at the lowest temperatures which were tested, approximately 700 C, the tungsten rods were observed to oxidize without vaporization. The remainder of the tests was conducted over the temperature range of 800 C to 1350 C. In these tests, the rods were found to have lost weight due to vaporization of the tungsten and the missing weight was collected in the downstream condensate

  16. A copper vapor laser by using a copper-vapor-complex reaction at a low temperature

    OpenAIRE

    Kano, Toshiyuki; Taniguchi, Hiroshi; Saito, Hiroshi

    1987-01-01

    A copper vapor laser performance by using ametal-vapor-complex reaction (Cu+AlBr3) is reported. The laser operation is obtained at a low temperature without externalheating because of the AlBr3 vapors evaporating at a room temperature. The copper vapor laser using this metal-vapor-complex reaction has an advantage of deposition-free of a metallic copper to the laser tube wall, which is different from the copper halide and the organometallic copper lasers.

  17. What Good is Raman Water Vapor Lidar?

    Science.gov (United States)

    Whitman, David

    2011-01-01

    Raman lidar has been used to quantify water vapor in the atmosphere for various scientific studies including mesoscale meteorology and satellite validation. Now the international networks of NDACC and GRUAN have interest in using Raman water vapor lidar for detecting trends in atmospheric water vapor concentrations. What are the data needs for addressing these very different measurement challenges. We will review briefly the scientific needs for water vapor accuracy for each of these three applications and attempt to translate that into performance specifications for Raman lidar in an effort to address the question in the title of "What good is Raman water vapor Iidar."

  18. Vapor deposition of tantalum and tantalum compounds

    International Nuclear Information System (INIS)

    Trkula, M.

    1996-01-01

    Tantalum, and many of its compounds, can be deposited as coatings with techniques ranging from pure, thermal chemical vapor deposition to pure physical vapor deposition. This review concentrates on chemical vapor deposition techniques. The paper takes a historical approach. The authors review classical, metal halide-based techniques and current techniques for tantalum chemical vapor deposition. The advantages and limitations of the techniques will be compared. The need for new lower temperature processes and hence new precursor chemicals will be examined and explained. In the last section, they add some speculation as to possible new, low-temperature precursors for tantalum chemical vapor deposition

  19. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  20. Safety assessment of in-vessel vapor explosion loads in next generation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang Hyun; Cho, Jong Rae; Choi, Byung Uk; Kim, Ki Yong; Lee, Kyung Jung [Korea Maritime University, Busan (Korea); Park, Ik Kyu [Seoul National University, Seoul (Korea)

    1998-12-01

    A safety assessment of the reactor vessel lower head integrity under in-vessel vapor explosion loads has been performed. The premixing and explosion calculations were performed using TRACER-II code. Using the calculated explosion pressures imposed on the lower head inner wall, strain calculations were performed using ANSYS code. The explosion analyses show that the explosion impulses are not altered significantly by the uncertain parameters of triggering location and time, fuel and vapor volume fractions in uniform premixture bounding calculations within the conservative ranges. Strain analyses using the calculated pressure loads on the lower head inner wall show that the vapor explosion-induced lower head failure is physically unreasonable. The static analysis using the conservative explosion-end pressure of 7,246 psia shows that the maximum equivalent strain is 4.3% at the bottom of lower head, which is less than the allowable threshold value of 11%. (author). 24 refs., 40 figs., 3 tabs.

  1. COGNITIVE RESERVE IN AGING

    Science.gov (United States)

    Tucker, Adrienne M.; Stern, Yaakov

    2011-01-01

    Cognitive reserve explains why those with higher IQ, education, occupational attainment, or participation in leisure activities evidence less severe clinical or cognitive changes in the presence of age-related or Alzheimer’s disease pathology. Specifically, the cognitive reserve hypothesis is that individual differences in how tasks are processed provide reserve against brain pathology. Cognitive reserve may allow for more flexible strategy usage, an ability thought to be captured by executive functions tasks. Additionally, cognitive reserve allows individuals greater neural efficiency, greater neural capacity, and the ability for compensation via the recruitment of additional brain regions. Taking cognitive reserve into account may allow for earlier detection and better characterization of age-related cognitive changes and Alzheimer’s disease. Importantly, cognitive reserve is not fixed but continues to evolve across the lifespan. Thus, even late-stage interventions hold promise to boost cognitive reserve and thus reduce the prevalence of Alzheimer’s disease and other age-related problems. PMID:21222591

  2. HYDROCARBONS RESERVES IN VENEZUELA

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Cruz, D.J.

    2007-07-01

    Venezuela is an important player in the energy world, because of its hydrocarbons reserves. The process for calculating oil and associated gas reserves is described bearing in mind that 90% of the gas reserves of Venezuela are associated to oil. Likewise, an analysis is made of the oil reserves figures from 1975 to 2003. Reference is also made to inconsistencies found by international experts and the explanations offered in this respect by the Ministry of Energy and Petroleum (MENPET) and Petroleos de Venezuela (PDVSA) regarding the changes that took place in the 1980s. In turn, Hubbert's Law is explained to determine peak production of conventional oil that a reservoir or field will reach, as well as its relationship with remaining reserves. Emphasis is placed on the interest of the United Nations on this topic. The reserves of associated gas are presented along with their relationship with the different crude oils that are produced and with injected gas, as well as with respect to the possible changes that would take place in the latter if oil reserves are revised. Some recommendations are submitted so that the MENPET starts preparing the pertinent policies ruling reserves. (auth)

  3. Ovarian reserve parameters

    DEFF Research Database (Denmark)

    Bentzen, J G; Forman, Julie Lyng; Pinborg, Anja

    2012-01-01

    2-5 of the menstrual cycle or during withdrawal bleeding, blood sampling and transvaginal sonography was performed. After adjusting for age, ovarian reserve parameters were lower among users than among non-users of hormonal contraception: serum AMH concentration by 29.8% (95% CI 19.9 to 38...... was observed between duration of hormonal-contraception use and ovarian reserve parameters. No dose-response relation was found between the dose of ethinyloestradiol and AMH or AFC. This study indicates that ovarian reserve markers are lower in women using sex steroids for contraception. Thus, AMH...... concentration and AFC may not retain their accuracy as predictors of ovarian reserve in women using hormonal contraception. Serum anti-Müllerian hormone (AMH) concentration is an indirect marker of the number of small follicles in the ovary and thereby the ovarian reserve. The AMH concentration is now widely...

  4. Importance Profiles for Water Vapor

    Science.gov (United States)

    Mapes, Brian; Chandra, Arunchandra S.; Kuang, Zhiming; Zuidema, Paquita

    2017-11-01

    Motivated by the scientific desire to align observations with quantities of physical interest, we survey how scalar importance functions depend on vertically resolved water vapor. Definitions of importance begin from familiar examples of water mass I m and TOA clear-sky outgoing longwave flux I OLR, in order to establish notation and illustrate graphically how the sensitivity profile or "kernel" depends on whether specific humidity S, relative humidity R, or ln( R) are used as measures of vapor. Then, new results on the sensitivity of convective activity I con to vapor (with implied knock-on effects such as weather prediction skill) are presented. In radiative-convective equilibrium, organized (line-like) convection is much more sensitive to moisture than scattered isotropic convection, but it exists in a drier mean state. The lesson for natural convection may be that organized convection is less susceptible to dryness and can survive and propagate into regions unfavorable for disorganized convection. This counterintuitive interpretive conclusion, with respect to the narrow numerical result behind it, highlights the importance of clarity about what is held constant at what values in sensitivity or susceptibility kernels. Finally, the sensitivities of observable radiance signals I sig for passive remote sensing are considered. While the accuracy of R in the lower free troposphere is crucial for the physical importance scalars, this layer is unfortunately the most difficult to isolate with passive remote sensing: In high emissivity channels, water vapor signals come from too high in the atmosphere (for satellites) or too low (for surface radiometers), while low emissivity channels have poor altitude discrimination and (in the case of satellites) are contaminated by surface emissions. For these reasons, active ranging (LiDAR) is the preferred observing strategy.

  5. Sodium vapor charge exchange cell

    International Nuclear Information System (INIS)

    Hiddleston, H.R.; Fasolo, J.A.; Minette, D.C.; Chrien, R.E.; Frederick, J.A.

    1976-01-01

    An operational sequential charge-exchange ion source yielding a 50 MeV H - current of approximately 8 mA is planned for use with the Argonne 500 MeV booster synchrotron. Progress is reported on the development of a sodium vapor charge-exchange cell as part of that planned effort. Design, fabrication, and operating results to date are presented and discussed

  6. Sodium vapor charge exchange cell

    International Nuclear Information System (INIS)

    Hiddleston, H.R.; Fasolo, J.A.; Minette, D.C.; Chrien, R.E.; Frederick, J.A.

    1976-01-01

    An operational sequential charge-exchange ion source yielding a 50 MeV H - current of approximately 8 mA is planned for use with the Argonne 500 MeV booster synchrotron. We report on the progress for development of a sodium vapor charge-exchange cell as part of that planned effort. Design, fabrication, and operating results to date are presented and discussed. (author)

  7. Convection in tropical cyclones associated with vapor volume reduction - a new concept

    Science.gov (United States)

    Mardhekar, D.

    2010-09-01

    Low pressure zone formation due to convection in a tropical cyclone is associated by a newly discovered phenomenon. The explanation is based on Avogadro's law. According to the law 18 grams (molecular weight expressed in grams) of water when evaporated occupies 22.414 litres of vapor at standard temperature and pressure (STP). Therefore, 1.0 gram of water in the vapor form will occupy 1.245 litres. That is, 1245 ml volume of vapor at STP when condensed will form 1.0 ml volume of water. Due to the phase change that is from water vapor to liquid water, huge reduction in volume occurs. The process of condensation of vapor into liquid water from the vapor component of the vapor-rich air is continuously taking place in a tropical cyclone particularly in the eye wall on a very large scale. The condensed water precipitates as rain or forms clouds. Each ml of the rain leaves behind a vacant space equal to 1245 ml forming a low-pressure zone and consequently a pressure gradient force is formed. Therefore, when there are continuous heavy rains in the eye wall, the magnitude of the low pressure zone and the pressure gradient force forming continuously in the condensation regions of the eye wall is gigantic. At the same time the latent heat released in the condensation process is absorbed by the remaining air component, it becomes warmer and buoyant, therefore ascends and ultimately escapes from the top of the cyclone as the outflow, again forming a low pressure zone. Thus, continuous condensation and continuous ascent and escape of warm air from the top together form a continuous pressure gradient and the vapour-rich air is continuously sucked up from below, that is from above the sea surface in the region of the eye wall due to the continuously forming pressure gradient force maintaining the near sea surface convergence of the vapour rich air. The value 1245 changes with change in temperature and pressure, but it does not affect the presented concept. The formation of the

  8. Skyline Reservation System

    Data.gov (United States)

    US Agency for International Development — Flight reservation application used for in-country flights by USAID and DoS staff in Afghanistan. The application is managed and maintained by the vendor and USAID...

  9. Disappearance of a detached vapor mass in subcooled water

    International Nuclear Information System (INIS)

    Inada, Shigeaki; Miyasaka, Yoshiki; Izumi, Ryotaro.

    1986-01-01

    Experiments on pool transition boiling of water under atmospheric pressure on a heated surface 10 mm in diameter were conducted for subcooling 15 - 50 K. The mass flux of condensation of a detached coalescent vapor bubble was experimentally estimated by a mathematical model based on the mass transfer mechanism of condensation. As a result, it is clarified that the mass flux of condensation of the detached bubble was influenced by the initial growing velocity of a vapor bubble immediately following the detached bubble. The disappearance velocity of the detached bubble defined as a ratio of the bubble diameter at the departure to the time required until the disappearance, is in the range 0.2 to 2.0 m/sec. The disappearance velocity is proportional to the initial growing velocity of the bubble, to the square of the heat flux of the heated surface and to the cube of the wall superheat, separately. (author)

  10. Detonation wave driven by condensation of supersaturated carbon vapor.

    Science.gov (United States)

    Emelianov, A; Eremin, A; Fortov, V; Jander, H; Makeich, A; Wagner, H Gg

    2009-03-01

    An experimental observation of a detonation wave driven by the energy of condensation of supersaturated carbon vapor is reported. The carbon vapor was formed by the thermal decay of unstable carbon suboxide C3O2 behind shock waves in mixtures containing 10-30% C3O2 in Ar. In the mixture 10% C3O2+Ar the insufficient heat release resulted in a regime of overdriven detonation. In the mixture 20% C3O2+Ar measured values of the pressure and wave velocity coincident with calculated Chapman-Jouguet parameters were attained. In the richest mixture 30% C3O2+Ar an excess heat release caused the slowing down of the condensation rate and the regime of underdriven detonation was observed.

  11. Use of GC/MS Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs - Standardized Protocol for On-Site Evaluation of Vapor Intrusion

    Science.gov (United States)

    2014-07-01

    is used in a wide variety of consumer products including hobby craft glues, oven cleaner, silver polish, water-proofing spray, lubricant spray, and...outdoors and the fan should be set at a speed that maintains at least 1 Pa negative pressure (i.e., vacuum ) relative to the outdoors. Larger (e.g., 4-5...increased vacuum (i.e., negative pressure) in the building may increase vapor flow from the subsurface into the building. However, it also may increase

  12. Vapor Liquid Equilibrium (VLE) in H2O-Amine-CO2 system

    OpenAIRE

    Ahmad, Rafiq

    2012-01-01

    New experimental data for vapor-liquid equilibrium of CO2 in aqueous solutions of 3M/26.84% wt, 1M/9% wt and 0.1M/0.89% wt AMP (2-amino-2-methyl-1-propanol) and 1.5M PZ are reported from 313 to 393K. Low pressure/temperature equilibrium apparatus was used to measure the CO2 partial pressure over loaded AMP solutions while total pressure was measured with high pressure/temperature equilibrium apparatus. The experiments cover the temperature range of (313K?353K) and CO2 partial pressure rang...

  13. New membrane preconcentration devices for trace vapor detection systems phase 1

    Science.gov (United States)

    Armstrong, D.; Baker, R. W.; Mohr, J.

    This report describes the results of a six month feasibility program to develop a membrane vapor concentration device. The device would be used to concentrate trace organic vapors in air prior to introduction to a detector instrument. In this way the complexity and cost of the instrumentation required to detect vapors emitted from hidden explosives could be reduced. The membrane concentrator involves the use of ultrathin silicone rubber composite membranes contained in a novel separation cell. Toluene was used as a model organic vapor for explosive vapors. The membrane system was able to obtain enrichments of as much as 50-fold with toluene at pressure ratios of less than 10 across the cell. However, the time to reach this degree of concentration was excessively long at 200 minutes. It appears that large amounts of the organic vapor are sorbed onto and into the membrane and adhesives of the membrane cell. It was not possible to overcome this sorption effect and reduce the system's lag time to a more useful value. Thus, this membrane concentration device does not appear to be a practical preconcentrator for a trace vapor detection instrument.

  14. The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer

    Science.gov (United States)

    Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

  15. Atomic mercury vapor inside a hollow-core photonic crystal fiber.

    Science.gov (United States)

    Vogl, Ulrich; Peuntinger, Christian; Joly, Nicolas Y; Russell, Philip St J; Marquardt, Christoph; Leuchs, Gerd

    2014-12-01

    We demonstrate high atomic mercury vapor pressure in a kagomé-style hollow-core photonic crystal fiber at room temperature. After a few days of exposure to mercury vapor the fiber is homogeneously filled and the optical depth achieved remains constant. With incoherent optical pumping from the ground state we achieve an optical depth of 114 at the 6(3)P(2) - 6(3)D(3) transition, corresponding to an atomic mercury number density of 6 × 10(10) cm(-3). The use of mercury vapor in quasi one-dimensional confinement may be advantageous compared to chemically more active alkali vapor, while offering strong optical nonlinearities in the ultraviolet region of the optical spectrum.

  16. A semiempirical correlation between enthalpy of vaporization and saturation concentration for organic aerosol.

    Science.gov (United States)

    Epstein, Scott A; Riipinen, Ilona; Donahue, Neil M

    2010-01-15

    To model the temperature-induced partitioning of semivolatile organics in laboratory experiments or atmospheric models, one must know the appropriate heats of vaporization. Current treatments typically assume a constant value of the heat of vaporization or else use specific values from a small set of surrogate compounds. With published experimental vapor-pressure data from over 800 organic compounds, we have developed a semiempirical correlation between the saturation concentration (C*, microg m(-3)) and the heat of vaporization (deltaH(VAP), kJ mol(-1)) for organics in the volatility basis set. Near room temperature, deltaH(VAP) = -11 log(10)C(300)(*) + 129. Knowledge of the relationship between C* and deltaH(VAP) constrains a free parameter in thermodenuder data analysis. A thermodenuder model using our deltaH(VAP) values agrees well with thermal behavior observed in laboratory experiments.

  17. Handbook on loss reserving

    CERN Document Server

    Schmidt, Klaus; Schnaus, Anja

    2016-01-01

    This handbook presents the basic aspects of actuarial loss reserving. Besides the traditional methods, it also includes a description of more recent ones and a discussion of certain problems occurring in actuarial practice, like inflation, scarce data, large claims, slow loss development, the use of market statistics, the need for simulation techniques and the task of calculating best estimates and ranges of future losses. In property and casualty insurance the provisions for payment obligations from losses that have occurred but have not yet been settled usually constitute the largest item on the liabilities side of an insurer's balance sheet. For this reason, the determination and evaluation of these loss reserves is of considerable economic importance for every property and casualty insurer. Actuarial students, academics as well as practicing actuaries will benefit from this overview of the most important actuarial methods of loss reserving by developing an understanding of the underlying stochastic models...

  18. Water vapor concentration measurement in singlet oxygen generator by using emission spectroscopy method and absorption at 1392nm

    Science.gov (United States)

    Zhao, Weili; Wang, Zengqiang; Fang, Benjie; Li, Qingwei; Jin, Yuqi; Sang, Fengting

    2005-12-01

    By using emission spectroscopy method and absorption at 1392nm, partial water pressure at the exit of a square pipe-array jet-type singlet oxygen generator (SPJSOG) for chemical oxygen-iodine laser (COIL) was measured. The water vapor fraction was calculated from the partial water pressure in the diagnostic cell when we assumed the water vapor fraction in the diagnostic cell is the same as that in the generator. The results from the two methods showed that the water vapor concentration is less than 0.08 in this SPJSOG during normal operation. The water vapor fraction decreases with the increasing of the pressure in the generator and rises with the increasing of buffer gas flow rate and the basic hydrogen peroxide (BHP) temperature in the case of constant chlorine flow rate. Measurements showed that the change of water vapor fraction due to BHP temperature could be ignored during normal operation. It is indicated that the gas flow velocity is the main reason that affects on the water vapor fraction in COIL. It is proved that the emission spectroscopy method is one of the simple and convenient ways to measure the water vapor concentration in singlet oxygen generator (SOG), especially in real time measurements. But absorption spectroscopy method, as a direct measurement, can give the more factual results of the water concentration.

  19. Lithium reserves and resources

    International Nuclear Information System (INIS)

    Evans, R.K.

    1978-01-01

    As a result of accelerating research efforts in the fields of secondary batteries and thermonuclear power generation, concern has been expressed in certain quarters regarding the availability, in sufficient quantities, of lithium. As part of a recent study by the National Research Council on behalf of the Energy Research and Development Administration, a subpanel was formed to consider the outlook for lithium. Principal areas of concern were reserves, resources and the 'surplus' available for energy applications after allowing for the growth in current lithium applications. Reserves and resources were categorized into four classes ranging from fully proved reserves to resources which are probably dependent upon the marketing of co-products to become economically attractive. Because of the proprietary nature of data on beneficiation and processing recoveries, the tonnages of available lithium are expressed in terms of plant feed. However, highly conservative assumptions have been made concerning mining recoveries and these go a considerable way to accounting for total losses. Western World reserves and resources of all classes are estimated at 10.6 million tonnes Li of which 3.5 million tonnes Li are located in the United States. Current United States capacity, virtually equivalent to Western World capacity, is 4700 tonnes Li and production in 1976 approximated to 3500 tonnes Li. Production for current applications is expected to grow to approx. 10,000 tonnes in year 2000 and 13,000 tonnes a decade later. The massive excess of reserves and resources over that necessary to support conventional requirements has limited the amount of justifiable exploration expenditures; on the last occasion, there was a a major increase in demand (by the USAEA) reserves and capacity were increased rapidly. There are no foreseeable reasons why this shouldn't happen again when the need is clear. (author)

  20. Scaling behavior of columnar structure during physical vapor deposition

    Science.gov (United States)

    Meese, W. J.; Lu, T.-M.

    2018-02-01

    The statistical effects of different conditions in physical vapor deposition, such as sputter deposition, have on thin film morphology has long been the subject of interest. One notable effect is that of column development due to differential chamber pressure in the well-known empirical model called the Thornton's Structure Zone Model. The model is qualitative in nature and theoretical understanding with quantitative predictions of the morphology is still lacking due, in part, to the absence of a quantitative description of the incident flux distribution on the growth front. In this work, we propose an incident Gaussian flux model developed from a series of binary hard-sphere collisions and simulate its effects using Monte Carlo methods and a solid-on-solid growth scheme. We also propose an approximate cosine-power distribution for faster Monte Carlo sampling. With this model, it is observed that higher chamber pressures widen the average deposition angle, and similarly increase the growth of column diameters (or lateral correlation length) and the column-to-column separation (film surface wavelength). We treat both the column diameter and the surface wavelength as power laws. It is seen that both the column diameter exponent and the wavelength exponent are very sensitive to changes in pressure for low pressures (0.13 Pa to 0.80 Pa); meanwhile, both exponents saturate for higher pressures (0.80 Pa to 6.7 Pa) around a value of 0.6. These predictions will serve as guides to future experiments for quantitative description of the film morphology under a wide range of vapor pressure.

  1. High Pressure Electrochemical Oxygen Generation for ISS, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Giner, Inc. has developed an advanced electrochemical static vapor feed oxygen (O2) concentrator (SVFOC) that offers a simple alternative to the use of pressure...

  2. SUIKERBOSRAND NATURE RESERVE

    African Journals Online (AJOL)

    Suikerbosrand Nature Reserve and fts educational facilities are run by the Transvaal. Division of. Nature Conservation. ... tion and the education facilities provided. The former are utilized mainly by the general public ... artist Paul Bosman (already reviewed in the EEASA newsletter). The co-founders of the Foundation are.

  3. Session 7: Reserve

    International Nuclear Information System (INIS)

    Bailey, R.; Crockford, G.

    2001-01-01

    The reserve session was devoted to some issues that came up through the workshop, which were grouped into three main areas: The Global Accelerator Network, Problems of stress and how to get organized to minimize them, What should an operations group be responsible for? This paper summarizes the discussions that took place. (author)

  4. School Shootings Stun Reservation

    Science.gov (United States)

    Borja, Rhea R.; Cavanagh, Sean

    2005-01-01

    This article deals with the impact brought by the school shootings at Red Lake Indian Reservation in Minnesota to the school community. A deeply troubled 16-year-old student shot and killed seven other people and himself at a high school. The nation's deadliest school attack since the 1999 slayings at Colorado's suburban Columbine High School took…

  5. SUIKERBOSRAND NATURE RESERVE

    African Journals Online (AJOL)

    reserve, the total length being 66 km with six overnight huts. There are also the BokmakiePie. Nature Troil. and the Cheetah Interpretive Troil. which can be used by day visitors. The former has two loops, one of 10 km and another of 17 km. The. Cheetah Troil. is much shorter and various points of interest are interpreted en ...

  6. Vapor Store Owner Beliefs and Messages to Customers.

    Science.gov (United States)

    Cheney, Marshall K; Gowin, Mary; Wann, Taylor Franklin

    2016-05-01

    Electronic cigarette (e-cigarette) use is becoming increasingly popular but little is known about the role of the local vapor store in promoting use and influencing customer attitudes and beliefs about vaping. Thirty-three vapor store owners were interviewed about their personal beliefs and attitudes about e-cigarettes and what they told customers about the health impact of using e-cigarettes. Interviews were recorded then transcribed, coded, and analyzed for themes. Vapor store owners used the internet to obtain information about vaping, most often from YouTube and industry sources. Owners often did not have the training to critically evaluate research studies posted on the internet. Owners promoted vaping as a healthier alternative to smoking and often compared it to a medical treatment. Owners considered ingredients in the e-liquid as safe to use if it was safe to eat and discussed other foods vapor ingredients were found in. Owners also discussed the safety of secondhand vapor. Owners described the health impact of nicotine in e-liquid by comparing nicotine to caffeine and promoted the nicotine in e-liquid as coming from vegetables rather than tobacco. Finally, owners talked about vaping as a habit rather than a continued addiction to nicotine. Local store owners are an important source of health information for current and potential e-cigarette users but their messages to customers may be based on incomplete or misinterpreted information. Understanding local store owner messages to customers in addition to internet-based messages is an important area for future public health research. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Acoustic Droplet Vaporization in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    Chung-Yin Lin

    2013-01-01

    Full Text Available This paper reviews the literature regarding the use of acoustic droplet vaporization (ADV in clinical applications of imaging, embolic therapy, and therapeutic delivery. ADV is a physical process in which the pressure waves of ultrasound induce a phase transition that causes superheated liquid nanodroplets to form gas bubbles. The bubbles provide ultrasonic imaging contrast and other functions. ADV of perfluoropentane was used extensively in imaging for preclinical trials in the 1990s, but its use declined rapidly with the advent of other imaging agents. In the last decade, ADV was proposed and explored for embolic occlusion therapy, drug delivery, aberration correction, and high intensity focused ultrasound (HIFU sensitization. Vessel occlusion via ADV has been explored in rodents and dogs and may be approaching clinical use. ADV for drug delivery is still in preclinical stages with initial applications to treat tumors in mice. Other techniques are still in preclinical studies but have potential for clinical use in specialty applications. Overall, ADV has a bright future in clinical application because the small size of nanodroplets greatly reduces the rate of clearance compared to larger contrast agent bubbles and yet provides the advantages of ultrasonographic contrast, acoustic cavitation, and nontoxicity of conventional perfluorocarbon contrast agent bubbles.

  8. Monofilament Vaporization Propulsion (MVP) System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Monofilament Vaporization Propulsion (MVP) is a new propulsion technology targeted at secondary payload applications. It does not compromise on performance while...

  9. Monofilament Vaporization Propulsion (MVP) System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Monofilament Vaporization Propulsion (MVP) is an innovative new propulsion technology targeted at secondary payload applications. The approach with MVP, rather than...

  10. Experiences of marijuana-vaporizer users.

    Science.gov (United States)

    Malouff, John M; Rooke, Sally E; Copeland, Jan

    2014-01-01

    Using a marijuana vaporizer may have potential harm-reduction advantages on smoking marijuana, in that the user does not inhale smoke. Little research has been published on use of vaporizers. In the first study of individuals using a vaporizer on their own initiative, 96 adults anonymously answered questions about their experiences with a vaporizer and their use of marijuana with tobacco. Users identified 4 advantages to using a vaporizer over smoking marijuana: perceived health benefits, better taste, no smoke smell, and more effect from the same amount of marijuana. Users identified 2 disadvantages: inconvenience of setup and cleaning and the time it takes to get the device operating for each use. Only 2 individuals combined tobacco in the vaporizer mix, whereas 15 combined tobacco with marijuana when they smoked marijuana. Almost all participants intended to continue using a vaporizer. Vaporizers seem to have appeal to marijuana users, who perceive them as having harm-reduction and other benefits. Vaporizers are worthy of experimental research evaluating health-related effects of using them.

  11. Mars water vapor, near-surface

    Science.gov (United States)

    Ryan, J. A.; Sharman, R. D.; Lucich, R. D.

    1982-01-01

    In a previous paper we concluded that the temperature sensors aboard the Viking landers (VL-1 and VL-2) were detecting the water vapor frost point. Analysis of one Mars year of data at both lander sites substantiates this conclusion. At VL-1 it is found that the water vapor mixing ratio is constant with height through the bulk of the atmosphere, most of the time. Exceptions are during the onset phases of the two major dust storms when temporary enhancement of near-surface vapor occurs (the same phenomenon is observed at VL-2), and some depletion of near-surface vapor during the decay phase of the first storm, possibly the second storm as well. The former suggests near-surface, northward transport of water vapor with the storms. The latter suggests adsorption of vapor on dust particles followed by surface deposition. At VL-2, severe near-surface depletion of water vapor occurs during northern autumn and winter. The residual vapor is in equilibrium with the surface condensate observed at the site during this period, indicating that the source region for the condensate must be aloft with downward transport by dust fall-out. Since the near-surface water vapor mixing ratio and concentration at VL-1 generally parallels the column abundance over VL-1 obtained by the orbiters, this suggests that VL-1 can be used to give a measure of column abundance for as long as the temperature sensors remain operational.

  12. Vaporization of trace element species from coal under gasification and combustion conditions: Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1989-03-01

    The objective of this project was to establish the chemical forms and relative abundance of trace inorganic vapor species in coal during combustion and gasification. A joint experimental and calculational program to observe the vaporization of Illinois No. 6 bituminous and Wyodak subbituminous was performed. Experimental studies were performed by Knudsen cell mass spectroscopy on samples of each coal that were ashed at low temperature by an oxygen plasma. To simulate actual coal more closely, some samples were only partially ashed to retain more of the original organic components. Vapor species were identified and their abundances measured over the temperature range 300-1700 K. In the first year of the program, vaporization from the coal ash alone was studied. Dynamic partial pressures were measured against temperature and time. Vapor species of 32 major or trace elements were identified. During the second year of the program, mass spectrometry experiments addressed the effects of added gases (O/sub 2/, CO/sub 2/, and H/sub 2/O) on the identities and abundances of trace element vapor species. Coincident with experimental studies, trace element vaporization behavior was evaluated by Gibbs energy minimization calculations. A data base including both solution and pure condensed and gaseous components was compiled. The behavior of Wyodak coal at 1 atm total pressure was evaluated over the temperature range 300--1800 K and the oxygen partial pressure range from 10/sup /minus/1/ to 10/sup /minus/25/ atm. Results were used to evaluate the effects on trace element volatility of several proposed strategies for containment removal. 13 refs., 23 figs., 23 tabs.

  13. Liquid-vapor equilibrium and interfacial properties of square wells in two dimensions

    Science.gov (United States)

    Armas-Pérez, Julio C.; Quintana-H, Jacqueline; Chapela, Gustavo A.

    2013-01-01

    Liquid-vapor coexistence and interfacial properties of square wells in two dimensions are calculated. Orthobaric densities, vapor pressures, surface tensions, and interfacial thicknesses are reported. Results are presented for a series of potential widths λ* = 1.4, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5, where λ* is given in units of the hard core diameter σ. Critical and triple points are explored. No critical point was found for λ* Armas-Pérez et al. [unpublished] as a hexatic phase transition. It is located at reduced temperatures T* = 0.47 and 0.35 for λ* = 1.4 and 1.5, respectively. Properties such as the surface tension, vapor pressure, and interfacial thickness do not present any discontinuity at these points. This amorphous solid branch does not follow the corresponding state principle, which is only applied to liquids and gases.

  14. The Strategic Petroleum Reserve

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The Strategic Petroleum Reserve program was set into motion by the 1975 Energy Policy and Conservation Act (EPCA). By 1990, 590 million barrels of oil had been placed in storage. Salt domes along the Gulf Coast offered ideal storage. Both sweet'' and sour'' crude oil have been acquired using various purchase options. Drawdown, sale, and distribution of the oil would proceed according to guidelines set by EPCA in the event of a severe energy supply disruption. (SM)

  15. Kinetics of chemical vapor deposition of boron on molybdenum

    International Nuclear Information System (INIS)

    Tanaka, W.; Nakaanishi, N.; Kato, E.

    1987-01-01

    Experimental rate data of chemical vapor deposition of boron by reduction of boron trichloride with hydrogen are analyzed to determine the reaction mechanism. The reaction orders with respect to the partial pressures of hydrogen and boron trichloride are one half and one third, respectively. It has been found that the outer layer of a deposited film is Mo/sub 2/B/sub 5/ and the inner layer is MoB by the use of X-ray diffraction and EPMA line analysis

  16. Energy characteristics of a transverse-discharge copper vapor laser

    Energy Technology Data Exchange (ETDEWEB)

    Artem' ev, A.Y.; Babeiko, Y.A.; Bakhtin, O.M.; Borovich, B.L.; Vasil' ev, L.A.; Gerts, V.E.; Nalegach, E.P.; Ratnikov, G.E.; Tatarintsev, L.V.; Ul' yanov, A.N.

    1980-09-01

    A study was made of the basic energy characteristics of a transverse-discharge copper vapor laser. The average laser output power in the yellow and green lasing components was determined as a function of the amplitude and repetition frequency of the excitation pulses, temperature of the discharge tube walls, and buffer gas pressure. The current-voltage characteristics of the discharge were investigated. An average laser output power of 75 W was obtained, at a pulse repetition frequency of 3 kHz.

  17. Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle

    KAUST Repository

    Kim, Youngdeuk

    2014-07-01

    The adsorption characteristics of microporous ferroaluminophosphate adsorbent (FAM-Z01, Mitsubishi Plastics) are evaluated for possible application in adsorption desalination and cooling (AD) cycles. A particular interest is its water vapor uptake behavior at assorted adsorption temperatures and pressures whilst comparing them to the commercial silica gels of AD plants. The surface characteristics are first carried out using N2 gas adsorption followed by the water vapor uptake analysis for temperature ranging from 20°C to 80°C. We propose a hybrid isotherm model, composing of the Henry and the Sips isotherms, which can be integrated to satisfactorily fit the experimental data of water adsorption on the FAM-Z01. The hybrid model is selected to fit the unusual isotherm shapes, that is, a low adsorption in the initial section and followed by a rapid vapor uptake leading to a likely micropore volume filling by hydrogen bonding and cooperative interaction in micropores. It is shown that the equilibrium adsorption capacity of FAM-Z01 can be up to 5 folds higher than that of conventional silica gels. Owing to the quantum increase in the adsorbate uptake, the FAM-Z01 has the potential to significantly reduce the footprint of an existing AD plant for the same output capacity. © 2014 Elsevier B.V.

  18. Partitioning Water Vapor and Carbon Dioxide Fluxes using Correlation Analysis

    Science.gov (United States)

    Scanlon, T. M.

    2008-12-01

    A variety of methods are currently available to partition water vapor fluxes (into components of transpiration and direct evaporation) and carbon dioxide fluxes (into components of photosynthesis and respiration), using chambers, isotopes, and regression modeling approaches. Here, a methodology is presented that accounts for correlations between high-frequency measurements of water vapor (q) and carbon dioxide (c) concentrations being influenced by their non-identical source-sink distributions and the relative magnitude of their constituent fluxes. Flux-variance similarity assumptions are applied separately to the stomatal and the non-stomatal exchange, and the flux components are identified by considering the q-c correlation. Water use efficiency for the vegetation, and how it varies with respect to vapor pressure deficit, is the only input needed for this approach that uses standard eddy covariance measurements. The method is demonstrated using data collected over a corn field throughout a growing season. In particular, the research focuses on the partitioning of the water flux with the aim of improving how direct evaporation is handled in soil-vegetation- atmosphere transfer models over the course of wetting and dry-down cycles.

  19. 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).

  20. Exergy Losses in the Szewalski Binary Vapor Cycle

    Directory of Open Access Journals (Sweden)

    Tomasz Kowalczyk

    2015-10-01

    Full Text Available In this publication, we present an energy and exergy analysis of the Szewalski binary vapor cycle based on a model of a supercritical steam power plant. We used energy analysis to conduct a preliminary optimization of the cycle. Exergy loss analysis was employed to perform a comparison of heat-transfer processes, which are essential for hierarchical cycles. The Szewalski binary vapor cycle consists of a steam cycle bottomed with an organic Rankine cycle installation. This coupling has a negative influence on the thermal efficiency of the cycle. However, the primary aim of this modification is to reduce the size of the power unit by decreasing the low-pressure steam turbine cylinder and the steam condenser. The reduction of the “cold end” of the turbine is desirable from economic and technical standpoints. We present the Szewalski binary vapor cycle in addition to a mathematical model of the chosen power plant’s thermodynamic cycle. We elaborate on the procedure of the Szewalski cycle design and its optimization in order to attain an optimal size reduction of the power unit and limit exergy loss.