ANNEALING OF POLYCRYSTALLINE THIN FILM SILICON SOLAR CELLS IN WATER VAPOUR AT SUB-ATMOSPHERIC PRESSURES

Directory of Open Access Journals (Sweden)

Peter Pikna

2014-10-01

Full Text Available Thin film polycrystalline silicon (poly-Si solar cells were annealed in water vapour at pressures below atmospheric pressure. PN junction of the sample was contacted by measuring probes directly in the pressure chamber filled with steam during passivation. Suns-VOC method and a Lock-in detector were used to monitor an effect of water vapour to VOC of the solar cell during whole passivation process (in-situ. Tested temperature of the sample (55°C – 110°C was constant during the procedure. Open-circuit voltage of a solar cell at these temperatures is lower than at room temperature. Nevertheless, voltage response of the solar cell to the light flash used during Suns-VOC measurements was good observable. Temperature dependences for multicrystalline wafer-based and polycrystalline thin film solar cells were measured and compared. While no significant improvement of thin film poly-Si solar cell parameters by annealing in water vapour at under-atmospheric pressures was observed up to now, in-situ observation proved required sensitivity to changing VOC at elevated temperatures during the process.

Vapour pressure measurements over liquid UO{sub 2} and (U,Pu)O{sub 2} by laser surface heating up to 5000 K

Energy Technology Data Exchange (ETDEWEB)

Babelot, J F; Brumme, G D [Institut fuer Angewandte Physik, TH Darmstadt (Germany); Kinsman, P R; Ohse, R W [Commission of the European Communities, European Institute for Transuranium Elements, EURATOM (Germany)

1977-07-01

Nuclear reactor technology requires the vapour pressure of fast breeder reactor fuels up to 6000 K in order to estimate the energy release In hypothetical fast reactor core meltdown accident. Both theoretical and experimental efforts are needed to provide the required data. In principle PVT data can be estimated by appropriate theoretical models, extrapolating measured data, or by purely thermodynamic calculations based on the extrapolation of reliable low temperature thermodynamic data. Direct measurements require the development of new experimental techniques for the extreme temperature range of interest in nuclear technology. The various theoretical approaches are characterized by the application of models which were conceived for simple molecular liquids and by the extrapolation of low temperature vapour pressure data over several thousand degrees, leading to a range In predicted critical point temperatures from 6000 K to almost 10000 K.

The vapour pressure of water as a function of solute concentration above aqueous solutions of fructose, sucrose, raffinose, erythritol, xylitol, and sorbitol

DEFF Research Database (Denmark)

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

2002-01-01

The vapour pressure of water above an aqueous solution of sucrose at T = 298.06 K has been measured for 9 sucrose mole fractions up to 0.12. Vapour pressure measurements have also been made on aqueous solutions of meso-erythritol, xylitol, sorbitol, fructose, and raffinose at T = 317.99 K...

High-pressure (vapour + liquid) equilibria for ternary systems composed by {(E)-2-hexenal or hexanal + carbon dioxide + water}: Partition coefficient measurement

International Nuclear Information System (INIS)

Bejarano, Arturo; López, Pablo I.; Valle, José M. del; Fuente, Juan C. de la

2015-01-01

Highlights: • A new apparatus based on a static–analytic method was assembled in this work. • This work reports high-pressure VLE data of (E)-2-hexenal or hexanal + CO 2 + water. • Data includes (CO 2 + water) partition coefficients of (E)-2-hexenal and hexanal. • High separation factors from water (∼10 4 ) were found especially for (E)-2-hexenal. • The data were obtained at T = (313, 323, and 333) K and pressures from (8 to 19) MPa. - Abstract: A new apparatus based on a static–analytic method assembled in this work was utilised to perform high-pressure (vapour + liquid) equilibria measurements of aqueous ternary systems. This work includes values of isothermal partition coefficients between CO 2 and water of two apple aroma constituents, (E)-2-hexenal and hexanal. Additionally, this work reports new experimental (vapour + liquid) equilibria measurements for the ternary systems (CO 2 + (E)-2-hexenal + water) and (CO 2 + hexanal + water), at fixed liquid phase composition (600 mg · kg −1 ), at temperatures of (313, 323 and 333) K and at pressures from (8 to 19) MPa. Vapour liquid interphase was checked and monitored visually for all the systems studied in this work. No liquid immiscibility was observed at the composition, temperatures and pressures studied. In order to suggest reasonable operation conditions for fractionation of aromas with dense carbon dioxide, partition coefficients of the aroma compounds between CO 2 and water along with their separation factors from water were calculated. Partition coefficients of (E)-2-hexenal between CO 2 and water were in the range of (6 to 91) and where found to be near six times higher than those of hexanal (9 to 17). Very high separation factors from water were observed (∼10 4 ) especially for (E)-2-hexenal. The highest separation factor, for both compounds, was found at a temperature of 313 K and pressures from (12 to 14) MPa

Spontaneous condensation of CHF2Cl vapour at high reduced pressures

International Nuclear Information System (INIS)

Bier, K.; Ehrler, F.; Kissau, G.; Lippig, V.; Schorsch, R.

1977-01-01

Spontaneous condensation at high reduced pressures was investigated in stationary jets of difluoromonochlormethane vapour (refrigerant R 22) expanding within an annular Laval nozzle. The onset of condensation in the so-called Wilson point was determined by measuring the static pressure along the nozzle axis. For 33 expansions carried out with the same nozzle geometry at different stagnation conditions - with dew points ranging from 32 to 64 per cent of the critical pressure - the Wilson points can be represented by a common Wilson line, which can be extended to the critical point. Considering the real gas properties of the supersaturated vapour, one obtains nucleation rates for the states on the measured Wilson line, which are considerably lower than those resulting from the usual ideal-gas calculation, the difference amounting from 4 to 9 orders of magnitude in the investigated region. A comparison with the collision rate of single molecules shows that the nucleation rates calculated for the real gas according to the classical Volmer-Frenkel thoery are plausible. An adequate interpretation of the experimental results on CHF 2 Cl with the Lothe-Pound theory, however, seems not possible, since the nucleation rate due to that theory would nearly attain and - at higher densities - even exceed the molecular collision rate. (orig.) [de

Low pressure water vapour plasma treatment of surfaces for biomolecules decontamination

DEFF Research Database (Denmark)

Fumagalli, F; Kylian, O; Amato, Letizia

2012-01-01

Decontamination treatments of surfaces are performed on bacterial spores, albumin and brain homogenate used as models of biological contaminations in a low-pressure, inductively coupled plasma reactor operated with water-vapour-based gas mixtures. It is shown that removal of contamination can...... be achieved using pure H2O or Ar/H2O mixtures at low temperatures with removal rates comparable to oxygen-based mixtures. Particle fluxes (Ar+ ions, O and H atomic radicals and OH molecular radicals) from water vapour discharge are measured by optical emission spectroscopy and Langmuir probe under several...... operating conditions. Analysis of particle fluxes and removal rates measurements illustrates the role of ion bombardment associated with O radicals, governing the removal rates of organic matter. Auxiliary role of hydroxyl radicals is discussed on the basis of experimental data. The advantages of a water...

A novel method of measuring the concentration of anaesthetic vapours using a dew-point hygrometer.

Science.gov (United States)

Wilkes, A R; Mapleson, W W; Mecklenburgh, J S

1994-02-01

The Antoine equation relates the saturated vapour pressure of a volatile substance, such as an anaesthetic agent, to the temperature. The measurement of the 'dew-point' of a dry gas mixture containing a volatile anaesthetic agent by a dew-point hygrometer permits the determination of the partial pressure of the anaesthetic agent. The accuracy of this technique is limited only by the accuracy of the Antoine coefficients and of the temperature measurement. Comparing measurements by the dew-point method with measurements by refractometry showed systematic discrepancies up to 0.2% and random discrepancies with SDS up to 0.07% concentration in the 1% to 5% range for three volatile anaesthetics. The systematic discrepancies may be due to errors in available data for the vapour pressures and/or the refractive indices of the anaesthetics.

Solvation-based vapour pressure model for (solvent + salt) systems in conjunction with the Antoine equation

International Nuclear Information System (INIS)

Senol, Aynur

2013-01-01

Highlights: • Vapour pressures of (solvent + salt) systems have been estimated through a solvation-based model. • Two structural forms of the generalized solvation model using the Antoine equation have been performed. • A simplified concentration-dependent vapour pressure model has been also processed. • The model reliability analysis has been performed in terms of a log-ratio objective function. • The reliability of the models has been interpreted in terms of the statistical design factors. -- Abstract: This study deals with modelling the vapour pressure of a (solvent + salt) system on the basis of the principles of LSER. The solvation model framework clarifies the simultaneous impact of several physical variables such as the vapour pressure of a pure solvent estimated by the Antoine equation, the solubility and solvatochromic parameters of the solvent and the physical properties of the ionic salt. It has been analyzed independently the performance of two structural forms of the generalized model, i.e., a relation depending on an integration of the properties of the solvent and the ionic salt and a relation on a reduced property-basis. A simplified concentration-dependent vapour pressure model has been also explored and implemented on the relevant systems. The vapour pressure data of sixteen (solvent + salt) systems have been processed to analyze statistically the reliability of existing models in terms of a log–ratio objective function. The proposed vapour pressure models match relatively well the observed performance, yielding the overall design factors of 1.066 and 1.073 for the solvation-based models with the integrated and reduced properties, and 1.008 for the concentration-based model, respectively

Bibliography on vapour pressure isotope effects

International Nuclear Information System (INIS)

Illy, H.; Jancso, G.

1976-03-01

The bibliography of research on vapour pressure isotope effects from 1919 to December 1975 is presented in chronological order. Within each year the references are listed alphabetically according to the name of the first author of each work. The bibliography is followed by a Compound Index containing the names o compounds, but the type of isotopic substituation is not shown. The Author Index includes all authors of the papers. (Sz.N.Z.)

Vapour pressures, densities, and viscosities of the (water + lithium bromide + potassium acetate) system and (water + lithium bromide + sodium lactate) system

International Nuclear Information System (INIS)

Lucas, Antonio de; Donate, Marina; Rodriguez, Juan F.

2006-01-01

Measurements of thermophysical properties (vapour pressure, density, and viscosity) of the (water + lithium bromide + potassium acetate) system LiBr:CH 3 COOK = 2:1 by mass ratio and the (water + lithium bromide + sodium lactate) system LiBr:CH 3 CH(OH)COONa = 2:1 by mass ratio were measured. The system, a possible new working fluid for absorption heat pump, consists of absorbent (LiBr + CH 3 COOK) or (LiBr + CH 3 CH(OH)COONa) and refrigerant H 2 O. The vapour pressures were measured in the ranges of temperature and absorbent concentration from T = (293.15 to 333.15) K and from mass fraction 0.20 to 0.50, densities and viscosities were measured from T = (293.15 to 323.15) K and from mass fraction 0.20 to 0.40. The experimental data were correlated with an Antoine-type equation. Densities and viscosities were measured in the same range of temperature and absorbent concentration as that of the vapour pressure. Regression equations for densities and viscosities were obtained with a minimum mean square error criterion

Vapour pressures for 1-(butoxymethoxy)butane (dibutoxymethane) and 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxybutane (methyl nonafluorobutyl ether) over the pressure range of (15–80) kPa

International Nuclear Information System (INIS)

Gárate, María P.; Bejarano, Arturo; Fuente, Juan C. de la

2016-01-01

Highlights: • Vapour pressures of two pure potential dry-cleaning solvent were measured. • Measurements were made over the temperature range of (294.6–442.7) K. • Three commonly used vapour pressure equations were fitted to the experimental data. • The parameters of Antoine and Wagner type equations were estimated. • The relative deviations (rmsd) from the three vapour-pressure equations were <0.6%. - Abstract: Saturated pressures of 1-(butoxymethoxy)butane (dibutoxymethane) and 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxybutane (methyl nonafluorobutyl ether), new potential solvents for dry-cleaning processes, were measured with a dynamic recirculation apparatus at a pressure range of (15–80) kPa, at temperatures of (390.4–442.7) K for dibutoxymethane and (294.6–322.4) K for methyl nonafluorobutyl ether. The vapour pressures were represented using the correlations of Antoine, extended Antoine and Wagner with relative root mean square deviations of, 1%, 6% and 0.6% for dibutoxymethane, and, 1%, 2% and 0.6% for methyl nonafluorobutyl ether, respectively. The experimental data of dibutoxymethane was compared with those available in literature, the result showed consistency between both data sets.

Vapour pressures of uranium and uranium nitride over UN(s)

International Nuclear Information System (INIS)

Venugopal, V.; Kulkarni, S.G.; Subbanna, C.S.; Sood, D.D.

1992-01-01

The vaporization of uranium mononitride is investigated in the temperature range 1757 to 2400 K by Knudsen effusion cell mass spectrometry. The vaporization occurs incongruently by the preferential loss of nitrogen and the formation of U(1) in equilibrium with UN phase. In addition the vapour phase has U(g) and UN(g). The vapour pressure of U(g) and UN(g) are measured and their dependence with temperatures can be represented by: log(p U (Pa))=[(10.59±0.18)-(26857±357)/T(K)] (1757 UN (Pa))=[(12.19±0.57)-(37347±235)/T(K)] (2190 f G 0 (UN, g, T)(kJ/mol)=352.75-0.0494 T(K). The equilibrium constants for the dissociation of UN(s)(K 1 ) and UN(g)(K 2 ) into gaseous elements are given by: log(K 1 )=(13.03±0.18)-(42857±357)/T(K), log(K 2 )=(0.84±0.60)-(5510±427)/T(K). (orig.)

Low pressure chemical vapour deposition of temperature resistant colour filters

International Nuclear Information System (INIS)

Verheijen, J.; Bongaerts, P.; Verspui, G.

1987-01-01

The possibility to deposit multilayer colour filters, based on optical inference, by means of Low Pressure Chemical Vapour Deposition (LPCVD) was investigated. The filters were made in a standard LPCVD system by alternate deposition of Si/sub 3/N/sub 4/ and SiO/sub 2/ layers. This resulted in filters with excellent colour uniformity on glass and quartz substrates. No difference was measured between theoretically calculated transmission and the transmission of the filters deposited by LPCVD. Temperature treatment at 600 0 C in air air showed no deterioration of filter quality and optical properties

Vapour pressure of caesium over nuclear graphite

International Nuclear Information System (INIS)

Faircloth, R.L.; Pummery, F.C.W.

1976-01-01

The vapour pressure of caesium over a fine-grained isotropic moulded gilsocarbon nuclear graphite intended for use in the manufacture of fuel tubes for the high temperature reactor has been determined as a function of temperature and concentration by means of the Knudsen effusion technique. The concentration range 0 to 10 μg caesium/g graphite was investigated and it was concluded that a Langmuir adsorption situation exists under these conditions. (author)

Calculation of vapour pressures over mixed carbide fuels

International Nuclear Information System (INIS)

Joseph, M.; Mathews, C.K.

1988-01-01

Vapour pressure over the uranium-plutonium mixed carbide (Usub(l-p) Pusub(p C) was calculated in the temperature range of 1300-9000 for various compositions (p=0.1 to 0.7). Effects of variation of the sesquicarbide content were also studied. The principle of corresponding states was applied to UC and mixed carbides to obtain the equation of state. (author)

The critical assessment of vapour pressure estimation methods for use in modelling the formation of atmospheric organic aerosol

Directory of Open Access Journals (Sweden)

M. H. Barley

2010-01-01

Full Text Available A selection of models for estimating vapour pressures have been tested against experimental data for a set of compounds selected for their particular relevance to the formation of atmospheric aerosol by gas-liquid partitioning. The experimental vapour pressure data (all <100 Pa of 45 multifunctional compounds provide a stringent test of the estimation techniques, with a recent complex group contribution method providing the best overall results. The effect of errors in vapour pressures upon the formation of organic aerosol by gas-liquid partitioning in an atmospherically relevant example is also investigated. The mass of organic aerosol formed under typical atmospheric conditions was found to be very sensitive to the variation in vapour pressure values typically present when comparing estimation methods.

Hydrogen and carbon vapour pressure isotope effects in liquid fluoroform studied by density functional theory

Energy Technology Data Exchange (ETDEWEB)

Oi, Takao; Mitome, Ryota; Yanase, Satoshi [Sophia Univ., Tokyo (Japan). Faculty of Science and Technology

2017-06-01

H/D and {sup 12}C/{sup 13}C vapour pressure isotope effects (VPIEs) in liquid fluoroform (CHF{sub 3}) were studied at the MPW1PW91/6-31 ++ G(d) level of theory. The CHF{sub 3} monomer and CHF{sub 3} molecules surrounded by other CHF{sub 3} molecules in every direction in CHF{sub 3} clusters were used as model molecules of vapour and liquid CHF{sub 3}. Although experimental results in which the vapour pressure of liquid {sup 12}CHF{sub 3} is higher than that of liquid {sup 12}CDF{sub 3} and the vapour pressure of liquid {sup 13}CHF{sub 3} is higher than that of liquid {sup 12}CHF{sub 3} between 125 and 212 K were qualitatively reproduced, the present calculations overestimated the H/D VPIE and underestimated the {sup 12}C/{sup 13}C VPIE. Temperature-dependent intermolecular interactions between hydrogen and fluorine atoms of neighbouring molecules were required to explain the temperature dependences of both H/D and {sup 12}C/{sup 13}C VPIEs.

The vapour pressures over saturated aqueous solutions of sodium and potassium acetates, chlorates, and perchlorates

Energy Technology Data Exchange (ETDEWEB)

Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Manzurola, Emanuel [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)

2007-08-15

Vapour pressures of water over saturated solutions of sodium acetate, potassium acetate, sodium perchlorate, and potassium perchlorate were determined over the (278 to 318) K temperature range and compared with available in the literature data. The cases of saturated solutions of sodium chlorate and potassium chlorate are also considered. The determined vapour pressures were used to obtain the water activities, the osmotic coefficients, and the molar enthalpies of vaporization in considered systems.

Turkish Undergraduates' Misconceptions of Evaporation, Evaporation Rate, and Vapour Pressure

Science.gov (United States)

Canpolat, Nurtac

2006-01-01

This study focused on students' misconceptions related to evaporation, evaporation rate, and vapour pressure. Open-ended diagnostic questions were used with 107 undergraduates in the Primary Science Teacher Training Department in a state university in Turkey. In addition, 14 students from that sample were interviewed to clarify their written…

Density and vapour pressure of mixed-solvent desiccant systems (propylene glycol or dipropylene glycol or tripropylene glycol + magnesium chloride + water)

International Nuclear Information System (INIS)

Chen, Shang-Yi; Soriano, Allan N.; Leron, Rhoda B.; Li, Meng-Hui

2014-01-01

In this present work, new experimental data for density and vapour pressure of the mixed-solvent desiccant systems containing {40 wt% glycol (propylene or dipropylene or tripropylene) + (4 or 9 or 16 wt%) magnesium chloride salt + water} were reported for temperatures up to 343.15 K at normal atmospheric condition. The density and vapour pressure data obtained are presented as a function of temperature and composition. An empirical equation was used to correlate the temperature and compositional dependence of the density values. A model based on the mean spherical approximation for aqueous electrolyte solutions incorporating the pseudo-solvent approach was used to represent the vapour pressure as a function of temperature and composition. Satisfactory results were obtained for both density and vapour pressure calculations

Vapour pressures of 1-methyl derivatives of benzimidazole, pyrazole and indole. The energy of the intermolecular hydrogen bond N-H⋯N

International Nuclear Information System (INIS)

Almeida, Ana R.R.P.; Monte, Manuel J.S.

2014-01-01

Highlights: • Vapour pressures of 1-methyl derivatives of benzimidazole, pyrazole and indole. • Enthalpies, entropies and Gibbs free energies of sublimation/vaporisation were derived. • Temperatures and enthalpies of fusion were determined. • Energy of the intermolecular hydrogen bond N-H⋯N was estimated. - Abstract: The vapour pressures of the liquid phase of 1-methylpyrazole, 1-methylbenzimidazole and 1-methylindole were measured over the temperature ranges (253.9 to 293.3) K, (303.2 to 372.5) K, and (268.6 to 341.9) K, respectively, using a static method. The vapour pressures of the crystalline phase of the two latter compounds were also measured at temperatures between (301.2 to 328.9) K and (267.6 to 275.5) K, respectively. The results obtained enabled the determination of the standard molar enthalpies and entropies of sublimation and of vaporisation at the mean temperatures of the measurements and at T = 298.15 K. The temperatures and molar enthalpies of fusion were determined using differential scanning calorimetry. The enthalpies of the intermolecular hydrogen bonds N-H⋯N in the crystalline phase of benzimidazole and pyrazole were determined and compared with the result previously determined for the energy of the intermolecular hydrogen bond in crystalline imidazole

Determining the vapour pressures of plant volatiles from gas chromatographic retention data

Czech Academy of Sciences Publication Activity Database

Hoskovec, Michal; Grygarová, D.; Cvačka, Josef; Streinz, Ludvík; Zima, J.; Verevkin, S. P.; Koutek, Bohumír

2005-01-01

Roč. 1083, - (2005), s. 161-172 ISSN 0021-9673 Institutional research plan: CEZ:AV0Z4055905 Keywords : vapour pressure * thermodinamic parameters * plant volatiles Subject RIV: CC - Organic Chemistry Impact factor: 3.096, year: 2005

The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

International Nuclear Information System (INIS)

Apelblat, Alexander; Korin, Eli

2007-01-01

Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems

The vapour pressures over saturated aqueous solutions of cadmium chloride, cadmium bromide, cadmium iodide, cadmium nitrate, and cadmium sulphate

Energy Technology Data Exchange (ETDEWEB)

Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)]. E-mail: apelblat@bgu.ac.il; Korin, Eli [Department of Chemical Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel)

2007-07-15

Vapour pressures of water over saturated solutions of cadmium salts (chloride, bromide, iodide, nitrate, and sulphate) were determined over the temperature range 280 K to 322 K and compared with the literature data. The vapour pressures determined were used to obtain the water activities, osmotic coefficients and the molar enthalpies of vaporization in the (cadmium salt + water) systems.

Chemical vapour deposition of silicon under reduced pressure in a hot-wall reactor: Equilibrium and kinetics

International Nuclear Information System (INIS)

Langlais, F.; Hottier, F.; Cadoret, R.

1982-01-01

Silicon chemical vapour deposition (SiH 2 Cl 2 /H 2 system), under reduced pressure conditions, in a hot-wall reactor, is presented. The vapour phase composition is assessed by evaluating two distinct equilibria. The homogeneous equilibrium , which assumes that the vapour phase is not in equilibrium with solid silicon, is thought to give an adequate description of the vapour phase in the case of low pressure, high gas velocities, good temperature homogeneity conditions. A comparison with heterogeneous equilibrium enables us to calculate the supersaturation so evidencing a highly irreversible growth system. The experimental determination of the growth rates reveals two distinct temperature ranges: below 1000 0 C, polycrystalline films are usually obtained with a thermally activated growth rate (+40 kcal mole -1 ) and a reaction order, with respect to the predominant species SiCl 2 , close to one; above 1000 0 C, the films are always monocrystalline and their growth rate exhibits a much lower or even negative activation energy, the reaction order in SiCl 2 remaining about one. (orig.)

Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography.

Science.gov (United States)

Haftka, Joris J H; Parsons, John R; Govers, Harrie A J

2006-11-24

A gas chromatographic method using Kováts retention indices has been applied to determine the liquid vapour pressure (P(i)), enthalpy of vaporization (DeltaH(i)) and difference in heat capacity between gas and liquid phase (DeltaC(i)) for a group of polycyclic aromatic hydrocarbons (PAHs). This group consists of 19 unsubstituted, methylated and sulphur containing PAHs. Differences in log P(i) of -0.04 to +0.99 log units at 298.15K were observed between experimental values and data from effusion and gas saturation studies. These differences in log P(i) have been fitted with multilinear regression resulting in a compound and temperature dependent correction. Over a temperature range from 273.15 to 423.15K, differences in corrected log P(i) of a training set (-0.07 to +0.03 log units) and a validation set (-0.17 to 0.19 log units) were within calculated error ranges. The corrected vapour pressures also showed a good agreement with other GC determined vapour pressures (average -0.09 log units).

Explicit modelling of SOA formation from α-pinene photooxidation: sensitivity to vapour pressure estimation

Directory of Open Access Journals (Sweden)

R. Valorso

2011-07-01

Full Text Available The sensitivity of the formation of secondary organic aerosol (SOA to the estimated vapour pressures of the condensable oxidation products is explored. A highly detailed reaction scheme was generated for α-pinene photooxidation using the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A. Vapour pressures (P^vap were estimated with three commonly used structure activity relationships. The values of P^vap were compared for the set of secondary species generated by GECKO-A to describe α-pinene oxidation. Discrepancies in the predicted vapour pressures were found to increase with the number of functional groups borne by the species. For semi-volatile organic compounds (i.e. organic species of interest for SOA formation, differences in the predicted P^vap range between a factor of 5 to 200 on average. The simulated SOA concentrations were compared to SOA observations in the Caltech chamber during three experiments performed under a range of NO_x conditions. While the model captures the qualitative features of SOA formation for the chamber experiments, SOA concentrations are systematically overestimated. For the conditions simulated, the modelled SOA speciation appears to be rather insensitive to the P^vap estimation method.

Validation for a new apparatus measuring water vapour enhancement factors up to 6 MPa

International Nuclear Information System (INIS)

Sairanen, H; Heinonen, M

2014-01-01

High accuracy dew-point measurements require a water vapour enhancement factor to correct the effects of pressure drop in a sampling line. The enhancement factor is also needed when a humidity quantity value is converted to another. In this paper a new apparatus for traceable measurements of the enhancement factor is presented along with the results of validation measurements with air and methane. The apparatus is designed for dew-point temperatures from −50 to +15 °C and the pressure range from atmospheric pressure up to 6 MPa. The performance of the apparatus was investigated by comparing measurement results to the literature data for air and the data calculated from published thermodynamic measurement results for methane. It is shown that the experimental results agree with the reference data within the estimated uncertainties. (paper)

Accelerated growth of oxide film on aluminium alloys under steam: Part I: Effects of alloy chemistry and steam vapour pressure on microstructure

DEFF Research Database (Denmark)

Din, Rameez Ud; Gudla, Visweswara C.; Jellesen, Morten S.

2015-01-01

of the oxide layeras well as the compactness increased with steam vapour pressure. The increase in vapour pressure also resulted in a better coverage over the intermetallic particles. Oxide layer showed a layered structure with more compact layer at the Al interface and a nano-scale needle like structure...

Vapour pressures and osmotic coefficients of binary mixtures containing alcohol and pyrrolidinium-based ionic liquids

International Nuclear Information System (INIS)

Calvar, N.; Domínguez, Á.; Macedo, E.A.

2013-01-01

Highlights: • Osmotic coefficients of alcohols with pyrrolidinium ILs are determined. • Experimental data were correlated with extended Pitzer model of Archer and MNRTL. • Mean molal activity coefficients and excess Gibbs free energies were calculated. • The results have been interpreted in terms of interactions. -- Abstract: The osmotic and activity coefficients and vapour pressures of mixtures containing primary (1-propanol, 1-butanol and 1-pentanol) and secondary (2-propanol and 2-butanol) alcohols with pyrrolidinium-based ionic liquids (1-butyl-1-methyl pyrrolidinium bis(trifluoromethylsulfonyl)imide, C 4 MpyrNTf 2 , and 1-butyl-1-methyl pyrrolidinium trifluoromethanesulfonate, C 4 MpyrTFO) have been experimentally determined at T = 323.15 K. For the experimental measurements, the vapour pressure osmometry technique has been used. The results on the influence of the structure of the alcohol and of the anion of the ionic liquid on the determined properties have been discussed and compared with literature data. For the correlation of the osmotic coefficients obtained, the Extended Pitzer model of Archer and the Modified Non-Random Two Liquids model were applied. The mean molal activity coefficients and the excess Gibbs energy for the studied mixtures were calculated from the parameters obtained in the correlation

Gas permeation measurement under defined humidity via constant volume/variable pressure method

KAUST Repository

Jan Roman, Pauls

2012-02-01

Many industrial gas separations in which membrane processes are feasible entail high water vapour contents, as in CO 2-separation from flue gas in carbon capture and storage (CCS), or in biogas/natural gas processing. Studying the effect of water vapour on gas permeability through polymeric membranes is essential for materials design and optimization of these membrane applications. In particular, for amine-based CO 2 selective facilitated transport membranes, water vapour is necessary for carrier-complex formation (Matsuyama et al., 1996; Deng and Hägg, 2010; Liu et al., 2008; Shishatskiy et al., 2010) [1-4]. But also conventional polymeric membrane materials can vary their permeation behaviour due to water-induced swelling (Potreck, 2009) [5]. Here we describe a simple approach to gas permeability measurement in the presence of water vapour, in the form of a modified constant volume/variable pressure method (pressure increase method). © 2011 Elsevier B.V.

Intercomparison of atmospheric water vapour measurements at a Canadian High Arctic site

Science.gov (United States)

Weaver, Dan; Strong, Kimberly; Schneider, Matthias; Rowe, Penny M.; Sioris, Chris; Walker, Kaley A.; Mariani, Zen; Uttal, Taneil; McElroy, C. Thomas; Vömel, Holger; Spassiani, Alessio; Drummond, James R.

2017-08-01

Water vapour is a critical component of the Earth system. Techniques to acquire and improve measurements of atmospheric water vapour and its isotopes are under active development. This work presents a detailed intercomparison of water vapour total column measurements taken between 2006 and 2014 at a Canadian High Arctic research site (Eureka, Nunavut). Instruments include radiosondes, sun photometers, a microwave radiometer, and emission and solar absorption Fourier transform infrared (FTIR) spectrometers. Close agreement is observed between all combination of datasets, with mean differences ≤ 1.0 kg m-2 and correlation coefficients ≥ 0.98. The one exception in the observed high correlation is the comparison between the microwave radiometer and a radiosonde product, which had a correlation coefficient of 0.92.A variety of biases affecting Eureka instruments are revealed and discussed. A subset of Eureka radiosonde measurements was processed by the Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN) for this study. Comparisons reveal a small dry bias in the standard radiosonde measurement water vapour total columns of approximately 4 %. A recently produced solar absorption FTIR spectrometer dataset resulting from the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) retrieval technique is shown to offer accurate measurements of water vapour total columns (e.g. average agreement within -5.2 % of GRUAN and -6.5 % of a co-located emission FTIR spectrometer). However, comparisons show a small wet bias of approximately 6 % at the high-latitude Eureka site. In addition, a new dataset derived from Atmospheric Emitted Radiance Interferometer (AERI) measurements is shown to provide accurate water vapour measurements (e.g. average agreement was within 4 % of GRUAN), which usefully enables measurements to be taken during day and night (especially valuable during polar night).

High mean water vapour pressure promotes the transmission of bacillary dysentery.

Directory of Open Access Journals (Sweden)

Guo-Zheng Li

Full Text Available Bacillary dysentery is an infectious disease caused by Shigella dysenteriae, which has a seasonal distribution. External environmental factors, including climate, play a significant role in its transmission. This paper identifies climate-related risk factors and their role in bacillary dysentery transmission. Harbin, in northeast China, with a temperate climate, and Quzhou, in southern China, with a subtropical climate, are chosen as the study locations. The least absolute shrinkage and selectionator operator is applied to select relevant climate factors involved in the transmission of bacillary dysentery. Based on the selected relevant climate factors and incidence rates, an AutoRegressive Integrated Moving Average (ARIMA model is established successfully as a time series prediction model. The numerical results demonstrate that the mean water vapour pressure over the previous month results in a high relative risk for bacillary dysentery transmission in both cities, and the ARIMA model can successfully perform such a prediction. These results provide better explanations for the relationship between climate factors and bacillary dysentery transmission than those put forth in other studies that use only correlation coefficients or fitting models. The findings in this paper demonstrate that the mean water vapour pressure over the previous month is an important predictor for the transmission of bacillary dysentery.

Experimental study of the vapour-liquid equilibria of HI-I-2-H2O ternary mixtures, Part 2: Experimental results at high temperature and pressure

International Nuclear Information System (INIS)

Larousse, B.; Lovera, P.; Borgard, J.M.; Roehrich, G.; Mokrani, N.; Maillault, C.; Doizi, D.; Dauvois, V.; Roujou, J.L.; Lorin, V.; Fauvet, P.; Carles, P.; Hartmann, J.M.

2009-01-01

In order to assess the choice of the sulphur-iodine thermochemical cycle for massive hydrogen production, a precise knowledge of the concentrations of the gaseous species (HI, I 2 , and H 2 O) in thermodynamic equilibrium with the liquid phase of the HI-I 2 -H 2 O ternary mixture is required, in a wide range of concentrations and for temperatures and pressures up to 300 degrees C and 50 bar. In the companion paper (Part 1) the experimental device was described, which enables the measurement of the total pressure and concentrations of the vapour phase (and thus the knowledge of the partial pressures of the different gaseous species) for the HI-I 2 -H 2 O mixture in the 20-140 degrees C range and up to 2 bar. This (Part 2) article describes the experimental device which enables similar measurements but now in the process domain. The results concerning concentrations in the vapour phase for the HI-I 2 -H 2 O initial mixture (with a global composition) in the 120-270 degrees C temperature range and up to 30 bar are presented. As previously, optical online diagnostics are used, based on recordings of infrared transmission spectra for HI and H 2 O and on UV/visible spectrometry for I 2 . The concentrations measured in the vapour phase are the first to describe the vapour composition under thermophysical conditions close to those of the distillation column. The experimental results are compared with a thermodynamic model and will help us to scale up and optimize the reactive distillation column we promote for the HI section of the sulphur-iodine cycle. (authors)

Vapour Pressure and Adiabatic Cooling from Champagne: Slow-Motion Visualization of Gas Thermodynamics

Science.gov (United States)

Vollmer, Michael; Mollmann, Klaus-Peter

2012-01-01

The recent introduction of inexpensive high-speed cameras offers a new experimental approach to many simple but fast-occurring events in physics. In this paper, the authors present two simple demonstration experiments recorded with high-speed cameras in the fields of gas dynamics and thermal physics. The experiments feature vapour pressure effects…

Predicting Vapour Pressures of Organic Compounds from Their Chemical Structure for Classification According to the VOCDirective and Risk Assessment in General

Directory of Open Access Journals (Sweden)

Frands Nielsen

2001-03-01

Full Text Available The use of organic compounds in the European Union will in the future be regulated in accordance with the Council Directive 1999/13/EC of 11 March 1999 [1]. In this directive, any organic compound is considered to be a volatile organic compound (VOC if it has a vapour pressure of 10 Pa or more at 20oC, or has a corresponding volatility under the particular condition of use. Introduction of such a limit will sometimes create problems, because vapour pressures cannot be determined with an infinite accuracy. Published data on vapour pressures for a true VOC will sometimes be found to be below 10 Pa and vice versa. When the same limit was introduced in the USA, a considerable amount of time and money were spent in vain on comparing incommensurable data [2]. In this paper, a model is presented for prediction of the vapour pressures of VOCs at 20oC from their chemical (UNIFAC structure. The model is implemented in a computer program, named P_PREDICT, which has larger prediction power close to 10 Pa at 20oC than the other models tested. The main advantage of the model, however, is that no experimental data, which will introduce uncertainty in the predictions, is needed. Classification using P_PREDICT, which only predicts one value for a given UNIFAC structure, is proposed. Organic compounds, which can be described by the UNIFAC groups in the present version of P_PREDICT, therefore, can be classified unambiguously as either VOCs or non-VOCs. Most people, including the present authors, feel uneasy about prioritising precision above accuracy. Modelling vapour pressures, however, could save a lot of money and the errors introduced are not large enough to have any substantial adverse effects for neither human beings nor the environment. A method for calculating vapour pressures at other temperatures than 20oC is tested with a dubious result. This method is used for EU risk assessment of new and existing chemicals.

Water vapour loss measurements on human skin.

NARCIS (Netherlands)

Valk, Petrus Gerardus Maria van der

1984-01-01

In this thesis, the results of a series of investigations into the barrier function of human skin are presented. In these investigations, the barrier function was assessed by water vapour loss measurements of the skin using a method based on gradient estimation.... Zie: Summary and conclusions

The ratio DT/μ for electrons in water vapour at 294 K

International Nuclear Information System (INIS)

Elford, M.T.

1995-01-01

The ratio D T /μ for electrons in water vapour (294 K) has been measured by the Townsend-Huxley method as a function of E/N (where E is the electric field strength and N the gas number density) at vapour pressures ranging from 0.103 to 0.413 kPa. For E/N ≤ 30 Td, where attachment and ionisation may be neglected, the values are found to be independent of vapour pressure and of the current ratio relation used to derive D T /μ values from the measured current ratios. The uncertainty of these D T /μ values is estimated to be T /μ measured at E/N > 30 Td were found to be strongly pressure dependent, the strength and sign of the dependence depending on E/N and the current ratio relation used. Since extrapolation to infinite pressure at each E/N value did not give the same value of D T /μ, it has not been possible to derive reliable D T /μ values for this higher E/N range. Possible causes of the observed pressure dependences are discussed. The present data are in good agreement with the values predicted by Ness and Robson for values of E/N ≤ 24 Td. 17 refs., 1 tab., 5 figs

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

Czech Academy of Sciences Publication Activity Database

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

2006-01-01

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

Continuous measurements of isotopic composition of water vapour on the East Antarctic Plateau

Directory of Open Access Journals (Sweden)

M. Casado

2016-07-01

Full Text Available Water stable isotopes in central Antarctic ice cores are critical to quantify past temperature changes. Accurate temperature reconstructions require one to understand the processes controlling surface snow isotopic composition. Isotopic fractionation processes occurring in the atmosphere and controlling snowfall isotopic composition are well understood theoretically and implemented in atmospheric models. However, post-deposition processes are poorly documented and understood. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum between surface water vapour, precipitation, surface snow and buried snow. Here, we target the isotopic composition of water vapour at Concordia Station, where the oldest EPICA Dome C ice cores have been retrieved. While snowfall and surface snow sampling is routinely performed, accurate measurements of surface water vapour are challenging in such cold and dry conditions. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces. Two infrared spectrometers have been deployed at Concordia, allowing continuous, in situ measurements for 1 month in December 2014–January 2015. Comparison of the results from infrared spectroscopy with laboratory measurements of discrete samples trapped using cryogenic sampling validates the relevance of the method to measure isotopic composition in dry conditions. We observe very large diurnal cycles in isotopic composition well correlated with temperature diurnal cycles. Identification of different behaviours of isotopic composition in the water vapour associated with turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction. Even if the vapour isotopic composition seems to be, at least part of the time, at equilibrium with the local snow, the slope of δD against δ18O prevents us from identifying

(Vapour + liquid) equilibria for (2,2-dimethoxypropane + methanol) and (2,2-dimethoxypropane + acetone)

International Nuclear Information System (INIS)

Jiang Hui; Li Haoran; Wang Congmin; Tan Taijun; Han Shijun

2003-01-01

The isothermal and isobaric (vapour + liquid) equilibria for (2,2-dimethoxypropane + methanol) and (2,2-dimethoxypropane + acetone) measured with an inclined ebulliometer are presented. The experimental results are analysed using the UNIQUAC equation with the temperature-dependent binary parameters with satisfactory results. Isobaric (vapour + liquid) equilibria data for these systems at p=99.99 kPa are compared with the literature data. Experimental vapour pressure of 2,2-dimethoxypropane are also included

Isothermal (vapour + liquid) equilibrium for binary mixtures of (tetrahydrofuran + 1,1,2,2-tetrachloroethane or tetrachloroethene) at nine temperatures

International Nuclear Information System (INIS)

Garriga, R.; Perez, P.; Gracia, M.

2006-01-01

Vapour pressures of (tetrahydrofuran + 1,1,2,2-tetrachloroethane, or tetrachloroethene) at nine temperatures between T = 283.15 K and T = 323.15 K were measured by a static method. The reduction of the vapour pressures data to obtain activity coefficients and excess molar Gibbs energies was carried out by fitting the vapour pressure data to the Redlich-Kister polynomial according to Barker's method. Excess molar volumes were also measured at T 298.15 K. A comparative analysis about the thermodynamic behaviour of both systems is performed, in terms of hydrogen bonding and electron-donor-acceptor interactions, as well as the resonance effect in tetrachloroethene

EVAPORATION: a new vapour pressure estimation methodfor organic molecules including non-additivity and intramolecular interactions

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S. Compernolle

2011-09-01

Full Text Available We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects, a method to predict (subcooled liquid pure compound vapour pressure p⁰ of organic molecules that requires 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: aldehydes, ketones, 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.

Erratum to: Measurement of copper vapour laser-induced ...

Indian Academy of Sciences (India)

Erratum to: Measurement of copper vapour laser-induced deformation of dielectric-coated mirror surface by. Michelson interferometer. A WAHID. ∗. , S KUNDU, J S B SINGH, A K SINGH, A KHATTAR,. S K MAURYA, J S DHUMAL and K DASGUPTA. Laser & Plasma Technology Division, Beam Technology Development ...

Vapour pressures and vapour-liquid equilibria of propyl acetate and isobutyl acetate with ethanol or 2-propanol at 0.15 MPa. Binary systems

Directory of Open Access Journals (Sweden)

Susial Pedro

2012-01-01

Full Text Available Vapour pressures of propyl acetate, isobutyl acetate and 2-propanol from 0.004 to 1.6 MPa absolute pressure and VLE data for the binary systems propyl acetate+ethanol, propyl acetate+2-propanol, isobutyl acetate+ethanol and isobutyl acetate+2-propanol at 0.15 MPa have been determined. The experimental VLE data were verified with the test of van Ness and the Fredenslund criterion. The propyl acetate+ethanol or +2-propanol binary systems have an azeotropic point at 0.15 MPa. The different versions of the UNIFAC and ASOG group contribution models were applied.

Effect of water vapour absorption on hydroxyl temperatures measured from Svalbard

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J. M. Chadney

2017-03-01

Full Text Available We model absorption by atmospheric water vapour of hydroxyl airglow emission using the HIgh-resolution TRANsmission molecular absorption database (HITRAN2012. Transmission coefficients are provided as a function of water vapour column density for the strongest OH Meinel emission lines in the (8–3, (5–1, (9–4, (8–4, and (6–2 vibrational bands. These coefficients are used to determine precise OH(8–3 rotational temperatures from spectra measured by the High Throughput Imaging Echelle Spectrograph (HiTIES, installed at the Kjell Henriksen Observatory (KHO, Svalbard. The method described in this paper also allows us to estimate atmospheric water vapour content using the HiTIES instrument.

Effect of dispersive long-range corrections to the pressure tensor: The vapour-liquid interfacial properties of the Lennard-Jones system revisited

Energy Technology Data Exchange (ETDEWEB)

Martínez-Ruiz, F. J.; Blas, F. J., E-mail: felipe@uhu.es [Departamento de Física Aplicada, Universidad de Huelva, 21071 Huelva (Spain); Centro de Investigación de Física Teórica y Matemática, Universidad de Huelva, 21071 Huelva (Spain); Mendiboure, B. [Laboratoire des Fluides Complexes et leurs Réservoirs, UMR5150, Université de Pau et des Pays de l’Adour, B. P. 1155, Pau Cedex 64014 (France); Moreno-Ventas Bravo, A. I. [Centro de Investigación de Física Teórica y Matemática, Universidad de Huelva, 21071 Huelva (Spain); Departamento de Geología, Facultad de Ciencias Experimentales, Universidad de Huelva, 21071 Huelva (Spain)

2014-11-14

We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r{sub c} = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r{sub c} = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial

Effect of dispersive long-range corrections to the pressure tensor: The vapour-liquid interfacial properties of the Lennard-Jones system revisited

International Nuclear Information System (INIS)

Martínez-Ruiz, F. J.; Blas, F. J.; Mendiboure, B.; Moreno-Ventas Bravo, A. I.

2014-01-01

We propose an extension of the improved version of the inhomogeneous long-range corrections of Janeček [J. Phys. Chem. B 110, 6264–6269 (2006)], presented recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)] to account for the intermolecular potential energy of spherical, rigid, and flexible molecular systems, to deal with the contributions to the microscopic components of the pressure tensor due to the dispersive long-range corrections. We have performed Monte Carlo simulations in the canonical ensemble to obtain the interfacial properties of spherical Lennard-Jones molecules with different cutoff distances, r c = 2.5, 3, 4, and 5σ. In addition, we have also considered cutoff distances r c = 2.5 and 3σ in combination with the inhomogeneous long-range corrections proposed in this work. The normal and tangential microscopic components of the pressure tensor are obtained using the mechanical or virial route in combination with the recipe of Irving and Kirkwood, while the macroscopic components are calculated using the Volume Perturbation thermodynamic route proposed by de Miguel and Jackson [J. Chem. Phys. 125, 164109 (2006)]. The vapour-liquid interfacial tension is evaluated using three different procedures, the Irving-Kirkwood method, the difference between the macroscopic components of the pressure tensor, and the Test-Area methodology. In addition to the pressure tensor and the surface tension, we also obtain density profiles, coexistence densities, vapour pressure, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the cutoff distance and the long-range corrections on these properties. According to our results, the main effect of increasing the cutoff distance (at fixed temperature) is to sharpen the vapour-liquid interface, to decrease the vapour pressure, and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness

An externally heated copper vapour laser

International Nuclear Information System (INIS)

Rochefort, P.A.; Sopchyshyn, F.C.; Selkirk, E.B.; Green, L.W.

1993-08-01

A pulsed Copper Vapour Laser (CVL), with a nominal 6 kHz repetition rate, was designed, build, and commissioned at Chalk River laboratories. The laser was required for Resonant Ionization Mass Spectroscopy (RIMS) experiments and for projects associated with Atomic Vapour laser Isotope Separation (AVLIS) studies. For the laser to operate, copper coupons position along the length of a ceramic tube must be heated sufficiently to create an appropriate vapour pressure. The AECL CVL uses an external heater element with a unique design to raise the temperature of the tube. The Cylindrical graphite heating element is shaped to compensate for the large radiation end losses of the laser tube. The use of an external heater saves the expensive high-current-voltage switching device from heating the laser tube, as in most commercial lasers. This feature is especially important given the intermittent usage typical of experimental research. As well, the heater enables better parametric control of the laser output when studying the lasing of copper (or other) vapour. This report outlines the lasing process in copper vapour, describes in detail all three major laser sub-systems: the laser body; the laser tube heater; the high voltage pulsed discharge; and, reports parametric measurements of the individual sub-systems and the laser system as a whole. Also included are normal operating procedures to heat up, run and shut down the laser

The vapour pressures over saturated aqueous solutions of DL-2-aminobutyric acid, 4-aminobutyric acid, sodium-D-gluconate, sodium hippurate, and potassium magnesium-L-aspartate

International Nuclear Information System (INIS)

Apelblat, Alexander; Korin, Eli

2008-01-01

Vapour pressures of water over saturated solutions of DL-2-aminobutyric acid, 4-aminobutyric acid, sodium-D-gluconate, sodium hippurate, and potassium magnesium-L-aspartate were determined over the (278 to 322) K temperature range. The determined vapour pressures were used to obtain the water activities, the molar enthalpies of vaporization, and the osmotic coefficients of sodium-D-gluconate

The vapour pressures over saturated aqueous solutions of DL-2-aminobutyric acid, 4-aminobutyric acid, sodium-D-gluconate, sodium hippurate, and potassium magnesium-L-aspartate

Energy Technology Data Exchange (ETDEWEB)

Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)], E-mail: apelblat@bgu.ac.il; Korin, Eli [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)

2008-05-15

Vapour pressures of water over saturated solutions of DL-2-aminobutyric acid, 4-aminobutyric acid, sodium-D-gluconate, sodium hippurate, and potassium magnesium-L-aspartate were determined over the (278 to 322) K temperature range. The determined vapour pressures were used to obtain the water activities, the molar enthalpies of vaporization, and the osmotic coefficients of sodium-D-gluconate.

Contribution to the liquid-vapour equilibrium of potassium and sodium mixtures

International Nuclear Information System (INIS)

Schreinlechner, I.; Schwarz, N.

1975-10-01

In this paper the phase diagram of the binary system potassium-sodium in the liquid-vapour range was calculated for different pressures and temperatures, assuming the two metals acting as ideal solution. The assumption was verified by experimental results. It is thus possible to calculate the separation factor for the rectification of potassium and to estimate the content of sodium in the vapour phase during experiments with vapourized potassium from the data of the vapour pressures of the pure metals. (author)

Discrete vapour cavity model with improved timing of opening and collapse of cavities

NARCIS (Netherlands)

Bergant, A.; Tijsseling, A.S.; Vítkovský, J.P.; Simpson, A.R.; Lambert, M.F.

2007-01-01

Transient vaporous cavitation occurs in hydraulic piping systems when the liquid pressure falls to the vapour pressure. Cavitation may occur as a localized vapour cavity (large void fraction) or as distributed vaporous cavitation (small void fraction). The discrete vapour cavity model (DVCM) with

Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography

NARCIS (Netherlands)

Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

2006-01-01

A gas chromatographic method using Kovats retention indices has been applied to determine the liquid vapour pressure (P-i), enthalpy of vaporization (Delta H-i) and difference in heat capacity between gas and liquid phase (Delta C-i) for a group of polycyclic aromatic hydrocarbons (PAHs). This group

Leaf injury characteristics of grassland species exposed to ozone in relation to soil moisture condition and vapour pressure deficit

International Nuclear Information System (INIS)

Bungener, P.; Balls, G.R.; Nussbaum, S.; Geissmann, M.; Grub, A.; Fuhrer, J.

1999-01-01

A range of plant species typical of semi-natural grasslands were tested for their sensitivity to short-term ozone injury under normal and reduced irrigation, and in relationship to air vapour pressure deficit. Potted specimens of 24 herbs, legumes and grasses were exposed during two seasons to four O 3 treatments in open-top chambers. The ozone treatments were: (a) charcoal-filtered air; (b) charcoal-filtered air plus ozone to match ambient levels; (c) charcoal-filtered air plus O 3 to ambient levels 1.5 and (d) charcoal-filtered air with ozone added to twice ambient levels during selected episodes of 7–13 d. During these ozone episodes, half of the plants in each ozone treatment received reduced irrigation (dry treatment) while the rest was kept under full irrigation (wet treatment). Type and date of first occurrence of leaf injury were noted during individual growth periods. Plants were harvested three times per year, and the percentage of injured leaves was recorded. Depending on species, injury symptoms were expressed as flecking (O 3 -specific injury), leaf yellowing or anthocyanin formation. Carum carvi and most species of the Fabaceae family (Onobrychis sativa, Trifolium repens, Trifolium pratense) were found to be most responsive to O 3 , injury occurring after only a few days of exposure in treatment (b). An episodic reduction in irrigation tended to reduce the expression of O 3 -specific symptoms, but only in species for which a reduction in soil moisture potential and an associated reduction in stomatal conductance during the dry episodes were observed. In other species, the protection from O 3 injury seemed to be of little importance. Using artificial neural networks the injury response of nine species was analysed in relation to Species, stomatal conductance, ozone as AOT40 (accumulated exposure above a threshold of 0.04 ppm for periods with global radiation ≥ 50 W m −2 (Fuhrer et al., 1997)), mean relative growth rate, air vapour pressure

Accelerated growth of oxide film on aluminium alloys under steam: Part II: Effects of alloy chemistry and steam vapour pressure on corrosion and adhesion performance

DEFF Research Database (Denmark)

Din, Rameez Ud; Bordo, Kirill; Jellesen, Morten Stendahl

2015-01-01

The steam treatment of aluminium alloys with varying vapour pressure of steamresulted in the growth of aluminium oxyhydroxide films of thickness range between 450 - 825nm. The surface composition, corrosion resistance, and adhesion of the produced films was characterised by XPS, potentiodynamic p...... of the vapour pressure of the steam. The accelerated corrosion and adhesion tests on steam generated oxide films with commercial powder coating verified that the performance of the oxide coating is highly dependent on the vapour pressure of the steam....... polarization, acetic acid salt spray, filiform corrosion test, and tape test. The oxide films formed by steam treatment showed good corrosion resistance in NaCl solution by significantly reducing anodic and cathodic activities. The pitting potential of the surface treated with steam was a function...

Studies of the kinetics and mechanism of the oxidation of uranium by dry and moist air A model for determining the oxidation rate over a wide range of temperatures and water vapour pressures

Science.gov (United States)

McGillivray, G. W.; Geeson, D. A.; Greenwood, R. C.

1994-01-01

The rate of oxidation of uranium metal by moist air has been measured at temperatures from 115 to 350°C and water vapour pressures from 0 to 47 kPa (350 Torr). From this and from previously reported data, a model has been developed which allows the rate of uranium oxidation to be calculated at any particular combination of temperature and water vapour pressure of interest, in the range 0-350°C and 0-101.3 kPa (760 Torr). The model is based on the assumption that the surface concentration of water determines the rate of reaction and that the adsorption of water onto the oxide follows a Langmuir type isotherm. Theoretical plots of rate as a function of water vapour pressure and Arrhenius plots derived from the model have been shown to be in good agreement with experimental data. The model assumes separate contributions to the overall observed rate from oxygen and water vapour. Surface studies have been carried out using SIMS (secondary ion mass spectrometry). Depth profiling of the oxide produced by isotopically labelled reagents ( 18O 2 and H 218O), has shown that oxygen from both reactants is incorporated into the oxide layer in the ratio predicted by the kinetic model. This supports a mechanism in which oxygen and water vapour produce separate diffusing species (possibly O 2- and OH -).

Vapour pressures, osmotic and activity coefficients for binary mixtures containing (1-ethylpyridinium ethylsulfate + several alcohols) at T = 323.15 K

International Nuclear Information System (INIS)

Calvar, Noelia; Gomez, Elena; Dominguez, Angeles; Macedo, Eugenia A.

2010-01-01

Osmotic coefficients of binary mixtures containing several primary and secondary alcohols (1-propanol, 2-propanol, 1-butanol, 2-butanol, and 1-pentanol) and the pyridinium-based ionic liquid 1-ethylpyridinium ethylsulfate were determined at T = 323.15 K using the vapour pressure osmometry technique. From the experimental results, vapour pressure and activity coefficients can be determined. For the correlation of osmotic coefficients, the extended Pitzer model modified by Archer, and the modified NRTL (MNRTL) model were used, obtaining deviations lower than 0.017 and 0.047, respectively. The mean molal activity coefficients and the excess Gibbs free energy for the binary mixtures studied were determined from the parameters obtained with the extended Pitzer model modified by Archer.

Measurement of water vapour transport through a porous non-hygroscopic material in a temperature gradient

DEFF Research Database (Denmark)

Hansen, Thor; Padfield, Tim; Hansen, Kurt Kielsgaard

2014-01-01

This was an experiment to identify the driving potential for water vapour diffusion through porous materials in a temperature gradient. The specimen of mineral fibre insulation was placed between a space with controlled temperature and relative humidity and a space with a controlled, higher...... temperature, and a measured but not controlled relative humidity (RH). This assembly was allowed to reach equilibrium with no vapour movement between the spaces, as tested by a constant RH on each side and by zero flux of water vapour measured in the cold side chamber. The RH and temperature values were...

The response of liquid-filled pipes to vapour collapse

International Nuclear Information System (INIS)

Tijsseling, A.S.; Fan, D.

1991-01-01

The collapse of vapour cavities in liquid is usually accompanied with almost instantaneous pressure rises. These pressure rises impose severe loads on liquid-conveying pipes whenever the cavities become sufficiently large. Due to the impact nature of loadings, movement of the pipe walls can be expected. Tests are performed in a water-filled closed pipe suspended by thin steel wires. Vaporous cavities are induced in the liquid by hitting the pipe axially by a steel rod. The volume of the cavities can be varied by changing the initial pressure of the water. The developing and collapsing of cavities in the liquid is inferred from pressure measurements. Strain gauges and a laser Doppler vibrometer are used to record the response of the pipe to these pressures. The test results are compared with predictions from a numerical model. The model describes 1) axial stress wave propagations in the pipe and 2) water hammer and cavitation phenomena in the liquid. Pipe and liquid interact via 1) the radial expansion and contraction of the pipe wall and 2) the closed ends of the pipe, where large vapour cavities may develop. (author)

Absorption by water vapour in the 1 to 2 μm region

International Nuclear Information System (INIS)

Smith, K.M.; Ptashnik, I.; Newnham, D.A.; Shine, K.P.

2004-01-01

The near-IR (in the range 5000-10 000 cm -1 , 1-2 μm) bands of water vapour have been measured in absorption in the laboratory at sub-Doppler spectral resolution (up to 0.0054 cm -1 after numerical apodisation) by Fourier transform spectroscopy. Measurements have been made at 296 K on pure water vapour (at pressures between 2 and 20 hPa) and mixtures of water and air (at total pressures of 100 and 1000 hPa), at optical path lengths in the range 0.26-9.75 m. Measured absorption intensities have been compared with values calculated using the HITRAN 2000 molecular database. These comparisons indicate that the intensities of the 2ν(1.4 μm) and 2ν+δ(1.14 μm) bands are underestimated in HITRAN 2000 by approximately 15% and 20%, respectively, for pure water vapour measurements, and 12% for both bands in the case of water-air mixtures. The ν+δ (1.86 μm) band is in good agreement (0.4% for pure water vapour and less than 6% for mixtures with air) with HITRAN 2000. For typical atmospheric conditions, these absorption bands are sufficiently strong that radiation is fully absorbed at wavelengths in the region of the band centres. Hence the extra absorption that has been identified has only a modest impact (0.16 W m -2 or about 0.2%) on the global-mean clear-sky absorption of solar radiation. The impact in the upper troposphere is several times larger

Studies of the kinetics and mechanism of the oxidation of uranium by dry and moist air. A model for determining the oxidation rate over a wide range of temperatures and water vapour pressures

Energy Technology Data Exchange (ETDEWEB)

McGillivray, G.W. (Atomic Weapons Establishment, Aldermaston, Reading (United Kingdom)); Geeson, D.A. (Atomic Weapons Establishment, Aldermaston, Reading (United Kingdom)); Greenwood, R.C. (Atomic Weapons Establishment, Aldermaston, Reading (United Kingdom))

1994-01-01

The rate of oxidation of uranium metal by moist air has been measured at temperatures from 115 to 350 C and water vapour pressures from 0 to 47 kPa (350 Torr). From this and from previously reported data, a model has been developed which allows the rate of uranium oxidation to be calculated at any particular combination of temperature and water vapour pressure of interest, in the range 0-350 C and 0-101.3 kPa (760 Torr). The model is based on the assumption that the surface concentration of water determines the rate of reaction and that the adsorption of water onto the oxide follows a Langmuir type isotherm. Theoretical plots of rate as a function of water vapour pressure and Arrhenius plots derived from the model have been shown to be in good agreement with experimental data. The model assumes separate contributions to the overall observed rate from oxygen and water vapour. Surface studies have been carried out using SIMS (secondary ion mass spectrometry). Depth profiling of the oxide produced by isotopically labelled reagents ([sup 18]O[sub 2] and H[sup 18][sub 2]O), has shown that oxygen from both reactants is incorporated into the oxide layer in the ratio predicted by the kinetic model. This supports a mechanism in which oxygen and water vapour produce separate diffusing species (possibly O[sup 2-] and OH[sup -]). (orig.)

Water vapour measurements during POLINAT 1

Energy Technology Data Exchange (ETDEWEB)

Ovarlez, J.; Ovarlez, H. [Centre National de la Recherche Scientifique, 91 - Palaiseau (France). Lab. de Meteorologie Dynamique

1997-12-31

The POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor)1 experiment has been performed within the framework of the Environment Programme of the Commission of the European Community. It was devoted to the study of the pollution from aircraft in the North Atlantic flight corridor, in order to investigate the impact of pollutants emitted by aircraft on the concentrations of ozone and other trace gases in the upper troposphere and lower stratosphere. For that experiment the water vapour content was measured with a frost-point hygrometer on board of the DLR Falcon research aircraft. This instrument is described, and some selected results are given. (author) 19 refs.

Water vapour measurements during POLINAT 1

Energy Technology Data Exchange (ETDEWEB)

Ovarlez, J; Ovarlez, H [Centre National de la Recherche Scientifique, 91 - Palaiseau (France). Lab. de Meteorologie Dynamique

1998-12-31

The POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor)1 experiment has been performed within the framework of the Environment Programme of the Commission of the European Community. It was devoted to the study of the pollution from aircraft in the North Atlantic flight corridor, in order to investigate the impact of pollutants emitted by aircraft on the concentrations of ozone and other trace gases in the upper troposphere and lower stratosphere. For that experiment the water vapour content was measured with a frost-point hygrometer on board of the DLR Falcon research aircraft. This instrument is described, and some selected results are given. (author) 19 refs.

Stripping of 1.04 MeV per nucleon krypton ions in high molecular weight vapours

International Nuclear Information System (INIS)

Eastham, D.A.; Joy, T.; Clark, R.B.; King, R.

1976-01-01

Equilibrium charge state distributions have been measured for 1.04 MeV per nucleon krypton ions in heavy vapours with molecular weights from 462 to 6500. Non-equilibrium data are presented for the heaviest vapour. A maximum increase of 0.8 in the mean charge is found relative to a conventional diatomic gas but the pressures required are two orders of magnitude less. (Auth.)

New approach for sustaining energetic, efficient and scalable non-equilibrium plasma in water vapours at atmospheric pressure

International Nuclear Information System (INIS)

Malik, Muhammad Arif; Schoenbach, Karl H

2012-01-01

Energetic and scalable non-equilibrium plasma was formed in pure water vapour at atmospheric pressure between wire-to-strip electrodes on a dielectric surface with one of the electrodes extended forming a conductive plane on the back side of the dielectric surface. The energy deposition increased by an order of magnitude compared with the conventional pulsed corona discharges under the same conditions. The scalability was demonstrated by operating two electrode assemblies with a common conductive plane between two dielectric layers. The energy yields for hydrogen and hydrogen peroxide generation were measured as ∼1.2 g H 2 /kWh and ∼4 g H 2 O 2 /kWh. (fast track communication)

Characterization and modelling of low-pressure rf discharges at 2-500 MHz for miniature alkali vapour dielectric barrier discharge lamps

International Nuclear Information System (INIS)

Venkatraman, Vinu; Shea, Herbert; Pétremand, Yves; Rooij, Nico de

2012-01-01

Low-pressure dielectric barrier discharge (DBD) alkali vapour lamps are of particular interest for portable atomic clocks because they (1) could enable low-power operation, (2) generate the precise required wavelength, (3) are planar simplifying chip-level integration and (4) use external electrodes, which increases the lifetime. Given the stringent requirements on lamps for atomic clocks, it is important to identify the parameters that can be optimized to meet these performance requirements (size, power consumption, stability, reliability). We report on the electrical and optical characteristics of dielectric barrier plasma discharges observed in two configurations: (1) in a vacuum chamber over a wide low-pressure range (2-100 mbar) for three different buffer gases (He, Ar, N 2 ) driven at different frequencies between 2 and 500 MHz and (2) on microfabricated hermetically sealed Rb vapour cells filled with 30 and 70 mbar of Ar. We discuss the optimum conditions for a low-power and stable operation of a Rb vapour DBD lamp, aimed at chip-scale atomic clocks. We also present the electrical modelling of the discharge parameters to understand the power distribution mechanisms and the input power to discharge power coupling efficiency.

UTLS water vapour from SCIAMACHY limb measurementsV3.01 (2002-2012).

Science.gov (United States)

Weigel, K; Rozanov, A; Azam, F; Bramstedt, K; Damadeo, R; Eichmann, K-U; Gebhardt, C; Hurst, D; Kraemer, M; Lossow, S; Read, W; Spelten, N; Stiller, G P; Walker, K A; Weber, M; Bovensmann, H; Burrows, J P

2016-01-01

The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard the Envisat satellite provided measurements from August 2002 until April 2012. SCIAMACHY measured the scattered or direct sunlight using different observation geometries. The limb viewing geometry allows the retrieval of water vapour at about 10-25 km height from the near-infrared spectral range (1353-1410 nm). These data cover the upper troposphere and lower stratosphere (UTLS), a region in the atmosphere which is of special interest for a variety of dynamical and chemical processes as well as for the radiative forcing. Here, the latest data version of water vapour (V3.01) from SCIAMACHY limb measurements is presented and validated by comparisons with data sets from other satellite and in situ measurements. Considering retrieval tests and the results of these comparisons, the V3.01 data are reliable from about 11 to 23 km and the best results are found in the middle of the profiles between about 14 and 20 km. Above 20 km in the extra tropics V3.01 is drier than all other data sets. Additionally, for altitudes above about 19 km, the vertical resolution of the retrieved profile is not sufficient to resolve signals with a short vertical structure like the tape recorder. Below 14 km, SCIAMACHY water vapour V3.01 is wetter than most collocated data sets, but the high variability of water vapour in the troposphere complicates the comparison. For 14-20 km height, the expected errors from the retrieval and simulations and the mean differences to collocated data sets are usually smaller than 10 % when the resolution of the SCIAMACHY data is taken into account. In general, the temporal changes agree well with collocated data sets except for the Northern Hemisphere extratropical stratosphere, where larger differences are observed. This indicates a possible drift in V3.01 most probably caused by the incomplete treatment of volcanic aerosols in the retrieval. In all other regions a

The molar enthalpies of solution and vapour pressures of saturated aqueous solutions of some cesium salts

International Nuclear Information System (INIS)

Apelblat, Alexander; Korin, Eli

2006-01-01

Vapour pressures of water over saturated solutions of cesium chloride, cesium bromide, cesium nitrate, cesium sulfate, cesium formate, and cesium oxalate were determined as a function of temperature. These vapour pressures were used to evaluate the water activities, osmotic coefficients and molar enthalpies of vapourization. Molar enthalpies of solution of cesium chloride, Δ sol H m (T = 295.73 K; m = 0.0622 mol . kg -1 ) = (17.83 ± 0.50) kJ . mol -1 ; cesium bromide, Δ sol H m (T = 293.99 K; m = 0.0238 mol . kg -1 ) = (26.91 ± 0.59) kJ . mol -1 ; cesium nitrate, Δ sol H m (T = 294.68 K; m = 0.0258 mol . kg -1 ) = (37.1 ± 2.3) kJ . mol -1 ; cesium sulfate, Δ sol H m (T = 296.43 K; m = 0.0284 mol . kg -1 ) (16.94 ± 0.43) kJ . mol -1 ; cesium formate, Δ sol H m (T = 295.64 K; m = 0.0283 mol . kg -1 ) = (11.10 ± 0.26) kJ . mol -1 and Δ sol H m (T = 292.64 K; m = 0.0577 mol . kg -1 ) = (11.56 ± 0.56) kJ . mol -1 ; and cesium oxalate, Δ sol H m (T = 291.34 K; m = 0.0143 mol . kg -1 ) = (22.07 ± 0.16) kJ . mol -1 were determined calorimetrically. The purity of the chemicals was generally greater than 0.99 mass fraction, except for HCOOCs and (COOCs) 2 where purities were approximately 0.95 and 0.97 mass fraction, respectively. The uncertainties are one standard deviations

Numerical analysis of the interaction between high-pressure resin spray and wood chips in a vapour stream

Directory of Open Access Journals (Sweden)

Massimo Milani

2016-04-01

Full Text Available This article investigates the interaction between the resin spray and the wood chips in a vapour stream using a multi-phase multi-component computational fluid dynamics approach. The interaction between the spray and the chips is one of the main issues in the industrial process for manufacturing medium density fibre boards. Thus, the optimization of this process can lead to important benefits, such as the reduction in the emission of formaldehyde-based toxic chemicals, the reduction in energy consumption in the blending process and energy saving in the fibreboard drying process. First step of the study is the numerical analysis of the resin injector in order to extend the experimental measurements carried out with water to the resin spray. The effects of the injector’s geometrical features on the spray formation are highlighted under different injection pressure values and needle displacements. Afterwards, the results obtained in the analysis of the single injector are used for the complete simulation of multi-injector rail where the mixing of the resin spray and wood chips takes place. The influence of the main operating conditions, such as the vapour and the wood chip flow rates, on the resin distribution is addressed in order to optimize the resination process.

Solvation pressure as real pressure: I. Ethanol and starch under negative pressure

CERN Document Server

Uden, N W A V; Faux, D A; Tanczos, A C; Howlin, B; Dunstan, D J

2003-01-01

The reality of the solvation pressure generated by the cohesive energy density of liquids is demonstrated by three methods. Firstly, the Raman spectrum of ethanol as a function of cohesive energy density (solvation pressure) in ethanol-water and ethanol-chloroform mixtures is compared with the Raman spectrum of pure ethanol under external hydrostatic pressure and the solvation pressure and hydrostatic pressure are found to be equivalent for some transitions. Secondly, the bond lengths of ethanol are calculated by molecular dynamics modelling for liquid ethanol under pressure and for ethanol vapour. The difference in bond lengths between vapour and liquid are found to be equivalent to the solvation pressure for the C-H sub 3 , C-H sub 2 and O-H bond lengths, with discrepancies for the C-C and C-O bond lengths. Thirdly, the pressure-induced gelation of potato starch is measured in pure water and in mixtures of water and ethanol. The phase transition pressure varies in accordance with the change in solvation pre...

Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems

DEFF Research Database (Denmark)

Ibrom, Andreas; Dellwik, Ebba; Flyvbjerg, Henrik K.

2007-01-01

datasets for this substantial measurement error. In contrast to earlier studies, a large number of spectra and raw data have been used in the analysis to define the low-pass filtering characteristic of the EC system. This revealed that the cut-off frequency of the closed-path EC system for water vapour......Turbulent water vapour fluxes measured with closed-path eddy correlation (EC) systems are unintentionally low-pass filtered by the system in a manner that varies with environmental conditions. Why and how is described here. So is the practical method that systematically corrects long-term flux...... concentration measurements decreases exponentially with increasing relative humidity. After correction for this unintended filtering, the fluxes are consistent with CO2 and H2O fluxes that were measured with an open-path sensor at the same time. The correction of water vapour flux measurements over a Beech...

Advancements, Challenges and Prospects of Chemical Vapour Pressure at Atmospheric Pressure on Vanadium Dioxide Structures

Directory of Open Access Journals (Sweden)

Charalampos Drosos

2018-03-01

Full Text Available Vanadium (IV oxide (VO2 layers have received extensive interest for applications in smart windows to batteries and gas sensors due to the multi-phases of the oxide. Among the methods utilized for their growth, chemical vapour deposition is a technology that is proven to be industrially competitive because of its simplicity when performed at atmospheric pressure (APCVD. APCVD’s success has shown that it is possible to create tough and stable materials in which their stoichiometry may be precisely controlled. Initially, we give a brief overview of the basic processes taking place during this procedure. Then, we present recent progress on experimental procedures for isolating different polymorphs of VO2. We outline emerging techniques and processes that yield in optimum characteristics for potentially useful layers. Finally, we discuss the possibility to grow 2D VO2 by APCVD.

Evaluation of balloon and satellite water vapour measurements in the Southern tropical and subtropical UTLS during the HIBISCUS campaign

Science.gov (United States)

Montoux, N.; Hauchecorne, A.; Pommereau, J.-P.; Lefèvre, F.; Durry, G.; Jones, R. L.; Rozanov, A.; Dhomse, S.; Burrows, J. P.; Morel, B.; Bencherif, H.

2009-07-01

Balloon water vapour in situ and remote measurements in the tropical upper troposphere and lower stratosphere (UTLS) obtained during the HIBISCUS campaign around 20° S in Brazil in February-March 2004 using a tunable diode laser (μSDLA), a surface acoustic wave (SAW) and a Vis-NIR solar occultation spectrometer (SAOZ) on a long duration balloon, have been used for evaluating the performances of satellite borne remote water vapour instruments available at the same latitude and measurement period. In the stratosphere, HALOE displays the best precision (2.5%), followed by SAGE II (7%), MIPAS (10%), SAOZ (20-25%) and SCIAMACHY (35%), all of which show approximately constant H2O mixing ratios between 20-25 km. Compared to HALOE of ±10% accuracy between 0.1-100 hPa, SAGE II and SAOZ show insignificant biases, MIPAS is wetter by 10% and SCIAMACHY dryer by 20%. The currently available GOMOS profiles of 25% precision show a positive vertical gradient in error for identified reasons. Compared to these, the water vapour of the Reprobus Chemistry Transport Model, forced at pressures higher than 95 hPa by the ECMWF analyses, is dryer by about 1 ppmv (20%). In the lower stratosphere between 16-20 km, most notable features are the steep degradation of MIPAS precision below 18 km, and the appearance of biases between instruments far larger than their quoted total uncertainty. HALOE and SAGE II (after spectral adjustment for reducing the bias with HALOE at northern mid-latitudes) both show decreases of water vapour with a minimum at the tropopause not seen by other instruments or the model, possibly attributable to an increasing error in the HALOE altitude registration. Between 16-18 km where the water vapour concentration shows little horizontal variability, and where the μSDLA balloon measurements are not perturbed by outgassing, the average mixing ratios reported by the remote sensing instruments are substantially lower than the 4-5 ppmv observed by the μSDLA. Differences

Water vapour and methane coupling in the stratosphere observed using SCIAMACHY solar occultation measurements

Directory of Open Access Journals (Sweden)

S. Noël

2018-04-01

Full Text Available An improved stratospheric water vapour data set has been retrieved from SCIAMACHY/ENVISAT solar occultation measurements. It is similar to that successfully applied to methane and carbon dioxide. There is now a consistent set of data products for the three constituents covering the altitudes 17–45 km, the latitude range between about 50 and 70° N, and the period August 2002 to April 2012. The new water vapour concentration profiles agree with collocated results from ACE-FTS and MLS/Aura to within  ∼  5 %. A significant positive linear change in water vapour for the time 2003–2011 is observed at lower stratospheric altitudes with a value of about 0.015 ± 0.008 ppmv year−1 around 17 km. Between 30 and 37 km the changes become significantly negative (about −0.01 ± 0.008 ppmv year−1; all errors are 2σ values. The combined analysis of the SCIAMACHY methane and water vapour time series shows the expected anti-correlation between stratospheric methane and water vapour and a clear temporal variation related to the Quasi-Biennial Oscillation (QBO. Above about 20 km most of the additional water vapour is attributed to the oxidation of methane. In addition short-term fluctuations and longer-term variations on a timescale of 5–6 years are observed. The SCIAMACHY data confirm that at lower altitudes the amount of water vapour and methane are transported from the tropics to higher latitudes via the shallow branch of the Brewer–Dobson circulation.

Microwave measurements of the absolute values of absorption by water vapour in the atmosphere.

Science.gov (United States)

Hogg, D C; Guiraud, F O

1979-05-31

MEASUREMENT of the absolute value of absorption by water vapour at microwave frequencies is difficult because the effect is so small. Far in the wings of the absorption lines, in the so-called 'windows' of the spectrum, it is especially difficult to achieve high accuracy in the free atmosphere. But it is in these windows that the behaviour of the absorption is important from both applied and scientific points of view. Satellite communications, remote sensing of the atmosphere, and radioastronomy, are all influenced by this behaviour. Measurements on an Earth-space path are reported here; the results indicate a nonlinear relationship between absorption and water-vapour content.

The effect of vapour pressure deficit on stomatal conductance, sap pH and leaf-specific hydraulic conductance in Eucalyptus globulus clones grown under two watering regimes.

Science.gov (United States)

Hernandez, Maria Jose; Montes, Fernando; Ruiz, Federico; Lopez, Gustavo; Pita, Pilar

2016-05-01

Stomatal conductance has long been considered of key interest in the study of plant adaptation to water stress. The expected increase in extreme meteorological events under a climate change scenario may compromise survival in Eucalyptus globulus plantations established in south-western Spain. We investigated to what extent changes in stomatal conductance in response to high vapour pressure deficits and water shortage are mediated by hydraulic and chemical signals in greenhouse-grown E. globulus clones. Rooted cuttings were grown in pots and submitted to two watering regimes. Stomatal conductance, shoot water potential, sap pH and hydraulic conductance were measured consecutively in each plant over 4 weeks under vapour pressure deficits ranging 0·42 to 2·25 kPa. Evapotranspiration, growth in leaf area and shoot biomass were also determined. There was a significant effect of both clone and watering regime in stomatal conductance and leaf-specific hydraulic conductance, but not in sap pH. Sap pH decreased as water potential and stomatal conductance decreased under increasing vapour pressure deficit. There was no significant relationship between stomatal conductance and leaf-specific hydraulic conductance. Stomata closure precluded shoot water potential from falling below -1·8 MPa. The percentage loss of hydraulic conductance ranged from 40 to 85 %. The highest and lowest leaf-specific hydraulic conductances were measured in clones from the same half-sib families. Water shortage reduced growth and evapotranspiration, decreases in evapotranspiration ranging from 14 to 32 % in the five clones tested. Changes in sap pH seemed to be a response to changes in atmospheric conditions rather than soil water in the species. Stomata closed after a considerable amount of hydraulic conductance was lost, although intraspecific differences in leaf-specific hydraulic conductance suggest the possibility of selection for improved productivity under water-limiting conditions

Isobaric (vapour + liquid) equilibria for the (1-pentanol + propionic acid) binary mixture at (53.3 and 91.3) kPa

International Nuclear Information System (INIS)

Mohsen-Nia, M.; Memarzadeh, M.R.

2010-01-01

Isobaric (vapour + liquid) equilibrium measurements have been reported for the binary mixture of (1-pentanol + propionic acid) at (53.3 and 91.3) kPa. Liquid phase activity coefficients were calculated from the equilibrium data. The thermodynamic consistency of the experimental results was checked using the area test and direct test methods. According to these criteria, the measured (vapour + liquid) equilibrium results were found to be consistent thermodynamically. The obtained results showed a maximum boiling temperature azeotrope at both pressures studied. The measured equilibrium results were satisfactorily correlated by the models of Wilson, UNIQUAC, and NRTL activity coefficients. The results obtained indicate that the performance of the NRTL model is superior to the Wilson and UNIQUAC models for correlating the measured isobaric (vapour + liquid) equilibrium data.

Consistent vapour-liquid equilibrium data containing lipids

DEFF Research Database (Denmark)

Cunico, Larissa; Ceriani, Roberta; Sarup, Bent

Consistent physical and thermodynamic properties of pure components and their mixtures are important for process design, simulation, and optimization as well as design of chemical based products. In the case of lipids, it was observed a lack of experimental data for pure compounds and also...... for their mixtures in open literature, what makes necessary the development of reliable predictive models based on limited data. To contribute to the missing data, measurements of isobaric vapour-liquid equilibrium (VLE) data of three binary mixtures at two different pressures were performed at State University...

Isopiestic determination of the osmotic coefficient and vapour pressure of N-R-4-(N,N-dimethylamino)pyridinium tetrafluoroborate (R = C4H9, C5H11, C6H13) in the ethanol solution at T = 298.15 K

International Nuclear Information System (INIS)

Sardroodi, Jaber Jahanbin; Atabay, Maryam; Azamat, Jafar

2012-01-01

Highlights: ► The osmotic coefficients of the solutions of ionic liquid in ethanol have been measured. ► Measured osmotic coefficients were correlated using Pitzer, e-NRTL and NRF models and polynomial equation. ► Vapour pressures were evaluated from the correlated osmotic coefficients. - Abstract: Osmotic coefficients of the solutions of room temperature ionic liquid N-R-4-(N,N-dimethylamino)pyridinium tetrafluoroborate (R = C 4 H 9 , C 5 H 11 , C 6 H 13 ) in ethanol have been measured at T = 298.15 K by the isopiestic method. The experimental osmotic coefficients have been correlated using the ion interaction model of Pitzer, electrolyte non-random two liquid (e-NRTL) model of Chen, non-random factor (NRF) and a fourth-order polynomial in terms of molality. The vapour pressures of the solutions studied have been evaluated from the osmotic coefficients.

Vapour phase motion in cryogenic systems containing superheated and subcooled liquids

Science.gov (United States)

Kirichenko, Yu. A.; Chernyakov, P. S.; Seregin, V. E.

The development of vent pipelines, and venting storage tanks for cryogenic liquids requires the knowledge of the law of motion as well as regularities of vapour content variation in the liquid and heat dissipation by the vapour phase. This is a theoretical study of the effect of superheating (subcooling) of the liquid, relative acceleration and reduced pressure upon the size and velocity of noninteracting vapour bubbles, moving in the liquid, and upon their resistance and heat transfer coefficients.

The Use of VMD Data/Model to Test Different Thermodynamic Models for Vapour-Liquid Equilibrium

DEFF Research Database (Denmark)

Abildskov, Jens; Azquierdo-Gil, M.A.; Jonsson, Gunnar Eigil

2004-01-01

Vacuum membrane distillation (VMD) has been studied as a separation process to remove volatile organic compounds from aqueous streams. A vapour pressure difference across a microporous hydrophobic membrane is the driving force for the mass transport through the membrane pores (this transport take...... place in vapour phase). The vapour pressure difference is obtained in VMD processes by applying a vacuum on one side of the membrane. The membrane acts as a mere support for the liquid-vapour equilibrium. The evaporation of the liquid stream takes place on the feed side of the membrane...... values; membrane type: PTFE/PP/PVDF; feed flow rate; feed temperature. A comparison is made between different thermodynamic models for calculating the vapour-liquid equilibrium at the membrane/pore interface. (C) 2004 Elsevier B.V. All rights reserved....

Studies on (2UF4 + H2 = 2UF3 + 2HF) and vapour pressure of UF3

International Nuclear Information System (INIS)

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

1982-01-01

Equilibrium constants for 2UF 4 (s) + H 2 (g) = 2UF 3 (s) + 2HF(g) have been measured in the temperature range 967 to 1120 K. An expression is given for the results. The results have been treated by second- and third-law methods to obtain ΔH 0 (298.15 K) and the values are given. The value of ΔS 0 (298.15 K) has been calculated by the second-law method. An expression is given for the vapour pressure of UF 3 (s), measured by the transpiration technique in the range 1229 to 1367 K. The standard enthalpy of vaporization ΔH 0 sub(v) (298.15 K) and the standard entropy of vaporization ΔS 0 sub(v) (298.15 K) have been calculated. The vaporization results have also been used for the calculation of ΔH 0 sub(f)(UF 3 , g, 298.15 K) and ΔS 0 sub(f)(UF 3 ,g, 298.15 K). (author)

Translation Effects in Fluorine Doped Tin Oxide Thin Film Properties by Atmospheric Pressure Chemical Vapour Deposition

Directory of Open Access Journals (Sweden)

Mohammad Afzaal

2016-10-01

Full Text Available In this work, the impact of translation rates in fluorine doped tin oxide (FTO thin films using atmospheric pressure chemical vapour deposition (APCVD were studied. We demonstrated that by adjusting the translation speeds of the susceptor, the growth rates of the FTO films varied and hence many of the film properties were modified. X-ray powder diffraction showed an increased preferred orientation along the (200 plane at higher translation rates, although with no actual change in the particle sizes. A reduction in dopant level resulted in decreased particle sizes and a much greater degree of (200 preferred orientation. For low dopant concentration levels, atomic force microscope (AFM studies showed a reduction in roughness (and lower optical haze with increased translation rate and decreased growth rates. Electrical measurements concluded that the resistivity, carrier concentration, and mobility of films were dependent on the level of fluorine dopant, the translation rate and hence the growth rates of the deposited films.

Microsphere formation in droplets using antisolvent vapour precipitation technique

OpenAIRE

Chew, Sean Jun Liang

2017-01-01

In previous studies, the antisolvent vapour precipitation method has been proven to produce uniformly sized lactose microspheres (1.0 µm) from a single droplet (1.2 mm diameter) at atmospheric pressure. These types of particles have potential applications in the pharmaceutical industry, especially due to their high dissolution rate. This project looked into the possibility of using antisolvent vapour precipitation to produce microspheres from finely atomised droplets. Microspheres in the sub-...

Thermodynamics of the ternary systems: (water + glycine, L-alanine and L-serine + di-ammonium hydrogen citrate) from volumetric, compressibility, and (vapour + liquid) equilibria measurements

International Nuclear Information System (INIS)

Sadeghi, Rahmat; Gholamireza, Afsaneh

2011-01-01

The apparent molar volumes and isentropic compressibility of glycine, L-alanine and L-serine in water and in aqueous solutions of (0.500 and 1.00) mol . kg -1 di-ammonium hydrogen citrate {(NH 4 ) 2 HCit} and those of (NH 4 ) 2 HCit in water have been obtained over the (288.15 to 313.15) K temperature range at 5 K intervals at atmospheric pressure from measurements of density and ultrasonic velocity. The apparent molar volume and isentropic compressibility values at infinite dilution of the investigated amino acids have been obtained and their variations with temperature and their transfer properties from water to aqueous solutions of (NH 4 ) 2 HCit have also been obtained. The results have been interpreted in terms of the hydration of the amino acids. In the second part of this work, water activity measurements by the isopiestic method have been carried out on the aqueous solutions of {glycine + (NH 4 ) 2 HCit}, {alanine + (NH 4 ) 2 HCit}, and {serine + (NH 4 ) 2 HCit} at T = 298.15 K at atmospheric pressure. From these measurements, values of vapour pressure, osmotic coefficient, activity coefficient and Gibbs free energy were obtained. The effect of the type of amino acids on the (vapour + liquid) equilibrium of the systems investigated has been studied. The experimental water activities have been correlated successfully with the segment-based local composition Wilson model. Furthermore, the thermodynamic behaviour of the ternary solutions investigated has been studied by using the semi-ideal hydration model and the linear concentration relations have been tested by comparing with the isopiestic measurements for the studied systems at T = 298.15 K.

Plasma assisted measurements of alkali metal concentrations in pressurized combustion processes

Energy Technology Data Exchange (ETDEWEB)

Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland). Dept. of Physics

1996-12-01

The plasma assisted method for continuous measurement of alkali concentrations in product gas flows of pressurized energy processes will be tested and applied at the 1.6 MW PFBC/G facility at Delft University of Technology in the Netherlands. During the reporting period the alkali measuring device has been tested under pressurized conditions at VTT Energy, DMT, Foster-Wheeler Energia and ABB Carbon. Measurements in Delft will be performed during 1996 after installation of the hot gas filter. The original plan for measurements in Delft has been postponed due to schedule delays in Delft. The results are expected to give information about the influence of different process conditions on the generation of alkali vapours, the comparison of different methods for alkali measurement and the specific performance of our system. This will be the first test of the plasma assisted measurement method in a gasification process. The project belongs to the Joule II extension program under contract JOU2-CT93-0431. (author)

Effect of alkanolammonium formates ionic liquids on vapour liquid equilibria of binary systems containing water, methanol, and ethanol

International Nuclear Information System (INIS)

Li Xuemei; Shen Chong; Li Chunxi

2012-01-01

Highlights ► Vapour pressures for six ternary systems containing an IL were measured. ► Components studied were water, ethanol, methanol, and alkanolammonium formates. ► The isobaric VLE were predicted using the fitted binary NRTL parameters. ► The ILs studied can generate a promising salt effect on VLE of azeotrope. ► [HMEA][HCOO] might be used as a potential entrainer in extractive distillation. - Abstract: Vapour pressures were measured using a quasi-static ebulliometer for the pseudo-binary mixtures of (water + ethanol), (water + methanol), and (methanol + ethanol) containing an alkanolammonium-based ionic liquid (IL), namely, mono-ethanolammonium formate ([HMEA][HCOO]) and di-ethanolammonium formate ([HDEA][HCOO]), respectively, with fixed IL mass fraction of 0.30 and over the temperature ranges of (292.12 to 371.13) K. The vapour pressures of the IL-containing ternary systems were favourably correlated using the NRTL model with an overall average absolute relative deviation (AARD) of 0.0082. Further, the salt effects of [HMEA][HCOO] and [HDEA][HCOO] on isobaric vapour liquid equilibria (VLE) of azeotrope and close boiling mixture, especially for the mixtures of (water + ethanol) and (methanol + ethanol), were investigated and compared with other ILs in terms of the x′–y phase diagrams predicted with the binary NRTL parameters. It is demonstrated that the relative volatilities of ethanol to water and ethanol to methanol are enhanced, and [HMEA][HCOO] might be used as a promising entrainer for the efficient separation of ethanol aqueous solution by special rectification.

Modelling of vapour explosion in stratified geometrie

International Nuclear Information System (INIS)

Picchi, St.

1999-01-01

When a hot liquid comes into contact with a colder volatile liquid, one can obtain in some conditions an explosive vaporization, told vapour explosion, whose consequences can be important on neighbouring structures. This explosion needs the intimate mixing and the fine fragmentation between the two liquids. In a stratified vapour explosion, these two liquids are initially superposed and separated by a vapor film. A triggering of the explosion can induce a propagation of this along the film. A study of experimental results and existent models has allowed to retain the following main points: - the explosion propagation is due to a pressure wave propagating through the medium; - the mixing is due to the development of Kelvin-Helmholtz instabilities induced by the shear velocity between the two liquids behind the pressure wave. The presence of the vapour in the volatile liquid explains experimental propagation velocity and the velocity difference between the two fluids at the pressure wave crossing. A first model has been proposed by Brayer in 1994 in order to describe the fragmentation and the mixing of the two fluids. Results of the author do not show explosion propagation. We have therefore built a new mixing-fragmentation model based on the atomization phenomenon that develops itself during the pressure wave crossing. We have also taken into account the transient aspect of the heat transfer between fuel drops and the volatile liquid, and elaborated a model of transient heat transfer. These two models have been introduced in a multi-components, thermal, hydraulic code, MC3D. Results of calculation show a qualitative and quantitative agreement with experimental results and confirm basic options of the model. (author)

Plasma assisted measurements of alkali metal concentrations in pressurized combustion processes

International Nuclear Information System (INIS)

Hernberg, R.; Haeyrinen, V.

1995-01-01

The plasma assisted method for continuous measurement of alkali metal concentrations in product gas flows of pressurized energy processes will be tested and applied at the 1.6 MW PFBC/G facility at Delft University of Technology in the Netherlands. Measurements will be performed during 1995 and 1996 at different stages of the research programme. The results are expected to give information about the influence of different process conditions on the generation of alkali metal vapours, the comparison of different methods for alkali measurement and the specific performance of our system. The project belongs to the Joule II extension program under contract JOU2-CT93-0431. (author)

Low vapour pressure deficit reduces the beneficial effect of elevated CO{sub 2} on growth of N{sub 2}-fixing alfalfa plants

Energy Technology Data Exchange (ETDEWEB)

Luis, I. De; Irigoyen, J.J.; Sanchez-Diaz, M. [Univ. de Navarra, Dept. de Fisioligia Vegetal, Pamplona (Spain)

2002-11-01

Plant responses to elevated CO{sub 2} can be modified by many environmental factors, but very little attention has been paid to the interaction between CO{sub 2} and changes in vapour pressure deficit (VPD). Thirty-day-old alfalfa plants (Medicago sativa L. cv. Aragon), which were inoculated with Sinorhizobium meliloti 102F78 strain, were grown for 1 month in controlled environment chambers at 25/15 deg C, 14 h photoperiod, and 600 mol m{sup -2} s{sup -1} photosynthetic photon flux (PPF), using a factorial combination of CO{sub 2} concentration (400 mol mol{sup -1} or 700 mol mol{sup -1}) and vapour pressure deficit (0.48 kPa or 1.74 kPa, which corresponded to relative humidities of 85% and 45% at 25 deg C, respectively). Elevated CO{sub 2} strongly stimulated plant growth under high VPD conditions, but this beneficial effect was not observed under low VPD. Under low VPD, elevated CO{sub 2} also did not enhance plant photosynthesis, and plant water stress was greatest for plants grown at elevated CO{sub 2} and low VPD. Moreover, plants grown under elevated CO{sub 2} and low VPD had a lower leaf soluble protein and photosynthetic activity (photosynthetic rate and carboxylation efficiency) than plants grown under elevated CO{sub 2} and high VPD. Elevated CO{sub 2} significantly increased leaf adaxial and abaxial temperatures. Because the effects of elevated CO{sub 2} were dependent on vapour pressure deficit, VPD needs to be controlled in experiments studying the effect of elevated CO{sub 2} as well as considered in the extrapolations of results to a warmer, high-CO{sub 2} world. (au)

CHEMICAL VAPOUR DEPOSITION FROM A RADIATION-SENSITIVE PRECURSOR

DEFF Research Database (Denmark)

2017-01-01

The present invention relates in one aspect to a method of depositing a thin film on a substrate by chemical vapour deposition (CVD) from a radiation-sensitive precursor substance. The method comprises the steps of: (i) placing the substrate in a reaction chamber of a CVD system; (ii) heating...... heating pulse followed by an idle period; (iii) during at least one of the idle periods, providing a pressure pulse of precursor substance inside the reaction chamber by feeding at least one precursor substance to the reaction chamber so as to establish a reaction partial pressure for thin film deposition...... is formed. According to a further aspect, the invention relates to a chemical vapour deposition (CVD) system for depositing a thin film onto a substrate using precursor substances containing at least one radiation sensitive species....

Thermodynamics of the ternary systems: (water + glycine, L-alanine and L-serine + di-ammonium hydrogen citrate) from volumetric, compressibility, and (vapour + liquid) equilibria measurements

Energy Technology Data Exchange (ETDEWEB)

Sadeghi, Rahmat, E-mail: rahsadeghi@yahoo.co [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Gholamireza, Afsaneh [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2011-02-15

The apparent molar volumes and isentropic compressibility of glycine, L-alanine and L-serine in water and in aqueous solutions of (0.500 and 1.00) mol . kg{sup -1} di-ammonium hydrogen citrate {l_brace}(NH{sub 4}){sub 2}HCit{r_brace} and those of (NH{sub 4}){sub 2}HCit in water have been obtained over the (288.15 to 313.15) K temperature range at 5 K intervals at atmospheric pressure from measurements of density and ultrasonic velocity. The apparent molar volume and isentropic compressibility values at infinite dilution of the investigated amino acids have been obtained and their variations with temperature and their transfer properties from water to aqueous solutions of (NH{sub 4}){sub 2}HCit have also been obtained. The results have been interpreted in terms of the hydration of the amino acids. In the second part of this work, water activity measurements by the isopiestic method have been carried out on the aqueous solutions of {l_brace}glycine + (NH{sub 4}){sub 2}HCit{r_brace}, {l_brace}alanine + (NH{sub 4}){sub 2}HCit{r_brace}, and {l_brace}serine + (NH{sub 4}){sub 2}HCit{r_brace} at T = 298.15 K at atmospheric pressure. From these measurements, values of vapour pressure, osmotic coefficient, activity coefficient and Gibbs free energy were obtained. The effect of the type of amino acids on the (vapour + liquid) equilibrium of the systems investigated has been studied. The experimental water activities have been correlated successfully with the segment-based local composition Wilson model. Furthermore, the thermodynamic behaviour of the ternary solutions investigated has been studied by using the semi-ideal hydration model and the linear concentration relations have been tested by comparing with the isopiestic measurements for the studied systems at T = 298.15 K.

Cr2O3 thin films grown at room temperature by low pressure laser chemical vapour deposition

International Nuclear Information System (INIS)

Sousa, P.M.; Silvestre, A.J.; Conde, O.

2011-01-01

Chromia (Cr 2 O 3 ) has been extensively explored for the purpose of developing widespread industrial applications, owing to the convergence of a variety of mechanical, physical and chemical properties in one single oxide material. Various methods have been used for large area synthesis of Cr 2 O 3 films. However, for selective area growth and growth on thermally sensitive materials, laser-assisted chemical vapour deposition (LCVD) can be applied advantageously. Here we report on the growth of single layers of pure Cr 2 O 3 onto sapphire substrates at room temperature by low pressure photolytic LCVD, using UV laser radiation and Cr(CO) 6 as chromium precursor. The feasibility of the LCVD technique to access selective area deposition of chromia thin films is demonstrated. Best results were obtained for a laser fluence of 120 mJ cm -2 and a partial pressure ratio of O 2 to Cr(CO) 6 of 1.0. Samples grown with these experimental parameters are polycrystalline and their microstructure is characterised by a high density of particles whose size follows a lognormal distribution. Deposition rates of 0.1 nm s -1 and mean particle sizes of 1.85 μm were measured for these films.

Intercomparison of TCCON and MUSICA Water Vapour Products

Science.gov (United States)

Weaver, D.; Strong, K.; Deutscher, N. M.; Schneider, M.; Blumenstock, T.; Robinson, J.; Notholt, J.; Sherlock, V.; Griffith, D. W. T.; Barthlott, S.; García, O. E.; Smale, D.; Palm, M.; Jones, N. B.; Hase, F.; Kivi, R.; Ramos, Y. G.; Yoshimura, K.; Sepúlveda, E.; Gómez-Peláez, Á. J.; Gisi, M.; Kohlhepp, R.; Warneke, T.; Dohe, S.; Wiegele, A.; Christner, E.; Lejeune, B.; Demoulin, P.

2014-12-01

We present an intercomparison between the water vapour products from the Total Carbon Column Observing Network (TCCON) and the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA), two datasets from ground-based Fourier Transform InfraRed (FTIR) spectrometers with good global representation. Where possible, comparisons to radiosondes are also included. The near-infrared TCCON measurements are optimized to provide precise monitoring of greenhouse gases for carbon cycle studies; however, TCCON's retrievals also produce water vapour products. The mid-infrared MUSICA products result from retrievals optimized to give precise and accurate information about H2O, HDO, and δD. The MUSICA water vapour products have been validated by extensive intercomparisons with H2O and δD in-situ measurements made from ground, radiosonde, and aircraft (Schneider et al. 2012, 2014), as well as by intercomparisons with satellite-based H2O and δD remote sensing measurements (Wiegele et al., 2014). This dataset provides a valuable reference point for other measurements of water vapour. This study is motivated by the limited intercomparisons performed for TCCON water vapour products and limited characterisation of their uncertainties. We compare MUSICA and TCCON products to assess the potential for TCCON measurements to contribute to studies of the water cycle, water vapour's role in climate and use as a tracer for atmospheric dynamics, and to evaluate the performance of climate models. The TCCON and MUSICA products result from measurements taken using the same FTIR instruments, enabling a comparison with constant instrumentation. The retrieval techniques differ, however, in their method and a priori information. We assess the impact of these differences and characterize the comparability of the TCCON and MUSICA datasets.

Initiation of a boiling liquid expanding vapour explosion

Energy Technology Data Exchange (ETDEWEB)

McDevitt, C.A.

1990-01-01

Boiling liquid expanding vapour explosions (BLEVEs) occur when a pressure liquefied gas tank is burst and the fluid is ejected to the atmosphere. As the liquid is exposed to a lower pressure it boils violently, causing an explosion which destroys the container. One litre tanks were filled with propane or R12, heated, and caused to rupture at specific test conditions to determine the parameters required for a BLEVE. Results showed that the energy stored in the liquid under pressure relative to the liquid at atmospheric conditions was a quantity which can be used to predict a BLEVE for the particular apparatus and conditions used. The possible importance of the development of a shock wave within the container during a BLEVE was noted. A shock tube was used to study the shock waves generated during a BLEVE. Temperature, liquid volume, rupture location, rupture area, and the fluid involved were varied. The pressure was measured vs time for periods immediately after the rupture. Photographs of the formation of pressure waves were obtained using spark Schlieren photography. Similarities to waves measured during detonations in ducts were noted. Pressure information was also gathered during BLEVEs of one litre cylinders, and this data is compared to that from the shock tube. Shock tube data showed that transverse waves formed from the initial pressure wave could be amplified. 37 refs., 54 figs., 11 tabs.

Properties of alumina films prepared by metal-organic chemical vapour deposition at atmospheric pressure in hte presence of small amounts of water

NARCIS (Netherlands)

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

1995-01-01

Thin alumina films were deposited on stainless steel, type AISI 304. The deposition process was carried out in nitrogen with low partial pressures of water (0–2.6 × 10−2 kPa (0−0.20 mmHg)) by metal-organic chemical vapour deposition (MOCVD) with aluminium-tri-sec-butoxide (ATSB) as the precursor.

Performance analysis of a potassium-steam two stage vapour cycle

International Nuclear Information System (INIS)

Mitachi, Kohshi; Saito, Takeshi

1983-01-01

It is an important subject to raise the thermal efficiency in thermal power plants. In present thermal power plants which use steam cycle, the plant thermal efficiency has already reached 41 to 42 %, steam temperature being 839 K, and steam pressure being 24.2 MPa. That is, the thermal efficiency in a steam cycle is facing a limit. In this study, analysis was made on the performance of metal vapour/steam two-stage Rankine cycle obtained by combining a metal vapour cycle with a present steam cycle. Three different combinations using high temperature potassium regenerative cycle and low temperature steam regenerative cycle, potassium regenerative cycle and steam reheat and regenerative cycle, and potassium bleed cycle and steam reheat and regenerative cycle were systematically analyzed for the overall thermal efficiency, the output ratio and the flow rate ratio, when the inlet temperature of a potassium turbine, the temperature of a potassium condenser, and others were varied. Though the overall thermal efficiency was improved by lowering the condensing temperature of potassium vapour, it is limited by the construction because the specific volume of potassium in low pressure section increases greatly. In the combinatipn of potassium vapour regenerative cycle with steam regenerative cycle, the overall thermal efficiency can be 58.5 %, and also 60.2 % if steam reheat and regenerative cycle is employed. If a cycle to heat steam with the bled vapor out of a potassium vapour cycle is adopted, the overall thermal efficiency of 63.3 % is expected. (Wakatsuki, Y.)

Modelling of vapour explosion in a stratified geometry

International Nuclear Information System (INIS)

Brayer, Claude

1994-01-01

A vapour explosion is the explosive vaporisation of a volatile liquid in contact with another hotter liquid. Such a violent vaporisation requires an intimate mixing and a fine fragmentation of both liquids. Based on a synthesis of published experimental results, the author of this research thesis reports the development of a new physical model which describes the explosion. In this model, the explosion propagation is due to the propagation of the pressure wave associated with this this explosion, all along the vapour film which initially separates both liquids. The author takes the presence of water in the liquid initially located over the film into account. This presence of vapour explains experimental propagation rates. Another consequence, when the pressure wave passes, is an acceleration of liquids at different rates below and above the film. The author considers that a mixture layer then forms from the point of disappearance of the film, between both liquids, and that fragmentation is due to the turbulence in this mixture layer. This fragmentation model is then introduced into an Euler thermodynamic, three-dimensional and multi-constituents code of calculation, MC3D, to study the influence of fragmentation on thermal exchanges between the various constituents on the volatile liquid vaporisation [fr

Effect of mono-, di- and tri-ethanolammonium tetrafluoroborate protonic ionic liquids on vapour liquid equilibria of ethanol aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Shen Chong [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Ma Xiaoyan [College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Lu Yingzhou [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Li Chunxi, E-mail: Licx@mail.buct.edu.c [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

2011-03-15

Vapour pressures were measured using a quasi-static ebulliometer for the binary mixture of (water + ethanol) containing one of three protonic ionic liquids (PIL), namely, mono-, di- or tri-ethanolammonium tetrafluoroborate, over the temperature range of (318.24 to 356.58) K at fixed PIL content of 0.30 in mass fraction. The vapour pressure data of the PIL-containing ternary systems were correlated using the NRTL equation with an overall root mean square deviation (RMSD) of 0.0092. The regressed NRTL parameters were used to predict the isobaric vapour liquid equilibria (VLE) for ternary systems (water + ethanol + PIL) at varying mass fraction of PIL and atmospheric pressure (101.3 kPa). It is shown that the effect of PILs on the VLE of the (water + ethanol) mixture follows the order: [HTEA][BF{sub 4}] > [HDEA][BF{sub 4}] > [HMEA][BF{sub 4}]. In addition, the relative volatilities of ethanol to water for pseudo-binary systems (water + ethanol + PIL) were calculated. The results indicate that the PILs studied can enhance the relative volatility of ethanol to water and even break the azeotropic behaviour of ethanol aqueous solution when PIL content is increased to a specified content.

Measurement of copper vapour laser-induced deformation of ...

Indian Academy of Sciences (India)

2014-02-14

Feb 14, 2014 ... Laser & Plasma Technology Division, Beam Technology Development Group,. Bhabha Atomic ... of dielectric-coated mirror, caused by an incident repetitive pulsed laser beam with high average power. Minimum ... the optical surface deformation, caused by irradiation by a copper vapour laser (CVL) beam.

Calculation of vapour bubble growth on the lower generatrix of horizontal tubes

International Nuclear Information System (INIS)

Chajka, V.D.

1987-01-01

The known models of vapour bubble growth are compared with experimental data. Cinematographic study of vapour formation during water boiling was carried out with elements of horizontal tubes of copper 10, 16, 24, 34 and 70 mm in diameter under the pressure of 100 kPa and specific thermal loadings of 20 and 40 kW/m 2 . According to the experimental data the main volume of vapour phase is occupied by vapour bubbles from the lower part of the horizontal tube. Five stages of vapour bubble growth on the lower generatrix of the horizontal tube: nucleation, growth to the point of breaking off from nucleate centre, the breaking off from the nucleate centre, the tube surface flowing around during floating up, the breaking off from the tube surface, were singled out. The shape of vapour volume varied during the whole period of the bubble growth and it was mainly determined by the horizontal tube diameter. The change of vapour bubble radius in time is the function of the horizontal tube diameter. Comparison of the experimental data with the known models of vapour bubble growth has shown, that every stage of vapour bubble growth on the lower generatrix of the tube is determined by the complex of thermal and hydrodynamic conditions, the effect of which depends on the horizontal tube diameter

Investigating Multiphase Flow Phenomena in Fine-Grained Reservoir Rocks: Insights from Using Ethane Permeability Measurements over a Range of Pore Pressures

Directory of Open Access Journals (Sweden)

Eric Aidan Letham

2018-01-01

Full Text Available The ability to quantify effective permeability at the various fluid saturations and stress states experienced during production from shale oil and shale gas reservoirs is required for efficient exploitation of the resources, but to date experimental challenges prevent measurement of the effective permeability of these materials over a range of fluid saturations. To work towards overcoming these challenges, we measured effective permeability of a suite of gas shales to gaseous ethane over a range of pore pressures up to the saturated vapour pressure. Liquid/semiliquid ethane saturation increases due to adsorption and capillary condensation with increasing pore pressure resulting in decreasing effective permeability to ethane gas. By how much effective permeability to ethane gas decreases with adsorption and capillary condensation depends on the pore size distribution of each sample and the stress state that effective permeability is measured at. Effective permeability decreases more at higher stress states because the pores are smaller at higher stress states. The largest effective permeability drops occur in samples with dominant pore sizes in the mesopore range. These pores are completely blocked due to capillary condensation at pore pressures near the saturated vapour pressure of ethane. Blockage of these pores cuts off the main fluid flow pathways in the rock, thereby drastically decreasing effective permeability to ethane gas.

Vapour pressure and excess Gibbs free energy of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane at temperature of 182.33K

International Nuclear Information System (INIS)

Lobo, L.Q.; Ferreira, A.G.M.; Fonseca, I.M.A.; Senra, A.M.P.

2006-01-01

The vapour pressure of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane was measured at T=182.33K covering most of the composition range. The excess Gibbs free energy of these mixtures has been derived from the measurements made. For the equimolar mixtures G m E (x 1 =0.5)=(835.5+/-5.8)J.mol -1 for (H 2 S+C 2 H 6 ) (820.1+/-2.4)J.mol -1 for (H 2 S+C 3 H 8 ), and (818.6+/-0.9)J.mol -1 for (H 2 S+n-C 4 H 10 ). The binary mixtures of H 2 S with ethane and with propane exhibit azeotropes, but that with n-butane does not

Effect of Liquid/Vapour Maldistribution on the Performance of Plate Heat Exchanger Evaporators

DEFF Research Database (Denmark)

Jensen, Jonas Kjær; Kærn, Martin Ryhl; Ommen, Torben Schmidt

2015-01-01

Plate heat exchangers are often applied as evaporators in industrial refrigeration and heat pump systems. In the design and modelling of such heat exchangers the flow and liquid/vapour distribution is often assumed to be ideal. However, maldistribution may occur and will cause each channel...... to behave differently due to the variation of the mass flux and vapour quality. To evaluate the effect of maldistribution on the performance of plate heat exchangers, a numerical model is developed in which the mass, momentum and energy balances are applied individually to each channel, including suitable...... correlations for heat transfer and pressure drop. The flow distribution on both the refrigerant and secondary side is determined based on equal pressure drop while the liquid/vapour distribution is imposed to the model. Results show that maldistribution may cause up to a 25 % reduction of the overall heat...

Water vapour and wind measurements by a two micron space lidar

Science.gov (United States)

Ghibaudo, J.-B.; Labandibar, J.-Y.

2018-04-01

AEROSPATIALE presents the main results of the feasibility study under ESA contract on a coherent 2μm lidar instrument capable of measuring water vapour and wind velocity in the planetary boundary layer. The selected instrument configuration and the associated performance are provided, and the main critical subsystems identified (laser configuration, coherent receiver chain architecture, frequency locking and offsetting architecture. The second phase of this study is dedicated to breadboard the most critical elements of such an instrument in order to technologically consolidate its feasibility.

The solubility of gold in H 2 O-H 2 S vapour at elevated temperature and pressure

Science.gov (United States)

Zezin, Denis Yu.; Migdisov, Artashes A.; Williams-Jones, Anthony E.

2011-09-01

This experimental study sheds light on the complexation of gold in reduced sulphur-bearing vapour, specifically, in H 2O-H 2S gas mixtures. The solubility of gold was determined in experiments at temperatures of 300, 350 and 365 °C and reached 2.2, 6.6 and 6.3 μg/kg, respectively. The density of the vapour varied from 0.02 to 0.22 g/cm 3, the mole fraction of H 2S varied from 0.03 to 0.96, and the pressure in the cell reached 263 bar. Statistically significant correlations of the amount of gold dissolved in the fluid with the fugacity of H 2O and H 2S permit the experimental data to be fitted to a solvation/hydration model. According to this model, the solubility of gold in H 2O-H 2S gas mixtures is controlled by the formation of sulphide or bisulphide species solvated by H 2S or H 2O molecules. Formation of gold sulphide species is favoured statistically over gold bisulphide species and thus the gold is interpreted to dissolve according to reactions of the form: Au(s)+(n+1)HS(g)=AuS·(HS)n(g)+H(g) Au(s)+HS(g)+mHO(g)=AuS·(HO)m(g)+H(g) Equilibrium constants for Reaction (A1) and the corresponding solvation numbers ( K A1 and n) were evaluated from the study of Zezin et al. (2007). The equilibrium constants as well as the hydration numbers for Reaction (A2) ( K A2 and m) were adjusted simultaneously by a custom-designed optimization algorithm and were tested statistically. The resulting values of log K A2 and m are -15.3 and 2.3 at 300 and 350 °C and -15.1 and 2.2 at 365 °C, respectively. Using the calculated stoichiometry and stability of Reactions (A1) and (A2), it is now possible to quantitatively evaluate the contribution of reduced sulphur species to the transport of gold in aqueous vapour at temperatures up to 365 °C. This information will find application in modelling gold ore-forming processes in vapour-bearing magmatic hydrothermal systems, notably those of epithermal environments.

Vapour pressure studies of uranium dioxide UO{sub 2} by the effusion method; Mesure de la tension de vapeur du bioxyde d'uranium UO{sub 2} par la methode d'effusion

Energy Technology Data Exchange (ETDEWEB)

Ohse, R W [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-07-01

A high temperature apparatus for vapour pressure measurements by Knudsen effusion method is described. Sample is heated in a tungsten cell in an electronic bombardment furnace. Several critical factors affecting the accuracy of measurements such as: - temperature distribution and measurement in the effusion cell, - CLAUSING factor and molecular flow, - compatibility between cell material and sample heated, are discussed with careful attention. Vapour pressure of UO{sub 2} has been studied between 2200 and 2800 K. Experimental points fit a curve expressed by: logP{sub mm} = 12.4264 - (3.3184/T * 10{sup 4}/T) which is in good agreement with previous results of literature. (author) [French] On decrit un appareil destine a la mesure des tensions de vapeur par la methode d'effusion de KNUDSEN. L'echantillon contenu dans une cellule en tungstene est chauffe par bombardement electronique. Apres examen critique des divers facteurs affectant l'exactitude des mesures, a savoir: - homogeneite et mesure de la temperature dans la cellule d'effusion, - facteur de 'CLAUSING' et loi de distribution en cosinus des molecules effusees, - compatibilite a chaud entre le materiau de la cellule et le materiau etudie. On a procede a la mesure de la tension de vapeur de UO{sub 2} qui est relativement bien connue. Entre 2200 et 2800 K les points experimentaux se placent sur une courbe: logP{sub mm} = 12.4264 - (3.3184/T * 10{sup 4}/T) en bon accord avec les valeurs citees dans la litterature. (auteur)

Aerosol formation from heat and mass transfer in vapour-gas mixtures

International Nuclear Information System (INIS)

Clement, C.F.

1985-01-01

Heat and mass transfer equations and their coupling to the equation for the aerosol size distribution are examined for mixtures in which pressure changes are slow. Specific results in terms of Cn (the condensation number) and Le (the Lewis number - the ratio of the relative rates of evaporation and condensation) are obtained for the proportion of vapour condensing as a aerosol during the cooling and heating of a mixture in a well-mixed cavity. The assumption of allowing no supersaturations, the validity of which is examined, is shown to lead to maximum aerosol formation. For water vapour-air mixtures predictions are made as to temperature regions in which aerosols will evaporate or not form in cooling processes. The results are also qualitatively applied to some atmospheric effects as well as to water aerosols formed in the containment of a pressurized water reactor following a possible accident. In this context, the present conclusion that the whereabouts of vapour condensation is controlled by heat and mass transfer, contrasts with previous assumptions that the controlling factor is relative surface areas. (U.K.)

Measurement of OH density and air-helium mixture ratio in an atmospheric-pressure helium plasma jet

International Nuclear Information System (INIS)

Yonemori, Seiya; Ono, Ryo; Nakagawa, Yusuke; Oda, Tetsuji

2012-01-01

The absolute density of OH radicals in an atmospheric-pressure helium plasma jet is measured using laser-induced fluorescence (LIF). The plasma jet is generated in room air by applying a pulsed high voltage onto a quartz tube with helium gas flow. The time-averaged OH density is 0.10 ppm near the quartz tube nozzle, decreasing away from the nozzle. OH radicals are produced from water vapour in the helium flow, which is humidified by water adsorbed on the inner surface of the helium line and the quartz tube. When helium is artificially humidified using a water bubbler, the OH density increases with humidity and reaches 2.5 ppm when the water vapour content is 200 ppm. Two-dimensional distribution of air-helium mixture ratio in the plasma jet is also measured using the decay rate of the LIF signal waveform which is determined by the quenching rate of laser-excited OH radicals. (paper)

Numerical Simulation of Pulsation Flow in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

Science.gov (United States)

Seryakov, A. V.; Konkin, A. V.

2017-11-01

The results of the numerical simulation of pulsations in the Laval-liked vapour channel of short low-temperature range heat pipes (HPs) are presented. The numerical results confirmed the experimentally obtained increase of the frequency of pulsations in the vapour channel of short HPs with increasing overheat of the porous evaporator relative to the boiling point of the working fluid. The occurrence of pressure pulsations inside the vapour channel in a short HPs is a complex phenomenon associated with the boiling beginning in the capillary-porous evaporator at high heat loads, and appearance the excess amount of vapour above it, leading to the increase in pressure P to a value at which the boiling point TB of the working fluid becomes higher than the evaporator temperature Tev. Vapour clot spreads through the vapour channel and condense, and then a rarefaction wave return from condenser in the evaporator, the boiling in which is resumed and the next cycle of the pulsations is repeated. Numerical simulation was performed using finite element method implemented in the commercial program ANSYS Multiphisics 14.5 in the two-dimensional setting of axis symmetric moist vapour flow with third kind boundary conditions.

Excess enthalpies and (vapour + liquid) equilibrium data for the binary mixtures of dimethylsulphoxide with ketones

International Nuclear Information System (INIS)

Radhamma, M.; Venkatesu, P.; Rao, M.V. Prabhakara; Prasad, D.H.L.

2007-01-01

Excess enthalpies (H E ), at ambient pressure and T = 298.15 K, have been measured by using a solution calorimeter for the binary liquid mixtures of dimethyl sulphoxide (DMSO) with ketones, as a function of composition. The ketones chosen in the present investigation were methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CH). The H E values are positive over the entire composition range for the three binary mixtures. Furthermore, the (vapour + liquid) equilibrium (VLE) was measured at 715 Torr for these mixtures, of different compositions, with the help of Swietoslawski-ebulliometer. The experimental temperature-mole fraction (t-x) data were used to compute Wilson parameters and then used to calculate the equilibrium vapour-phase compositions as well as the theoretical points for these binary mixtures. These Wilson parameters are used to calculate activity coefficients (γ) and these in turn to calculate excess Gibbs free energy (G E ). The intermolecular interactions and structural effects were analyzed on the basis of the measured and derived properties

Cr{sub 2}O{sub 3} thin films grown at room temperature by low pressure laser chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Sousa, P.M. [Universidade de Lisboa, Faculdade de Ciencias, Departamento de Fisica and ICEMS, Campo Grande, Ed. C8, 1749-016 Lisboa (Portugal); Silvestre, A.J., E-mail: asilvestre@deq.isel.ipl.p [Instituto Superior de Engenharia de Lisboa and ICEMS, R. Conselheiro Emidio Navarro 1, 1959-007 Lisboa (Portugal); Conde, O. [Universidade de Lisboa, Faculdade de Ciencias, Departamento de Fisica and ICEMS, Campo Grande, Ed. C8, 1749-016 Lisboa (Portugal)

2011-03-31

Chromia (Cr{sub 2}O{sub 3}) has been extensively explored for the purpose of developing widespread industrial applications, owing to the convergence of a variety of mechanical, physical and chemical properties in one single oxide material. Various methods have been used for large area synthesis of Cr{sub 2}O{sub 3} films. However, for selective area growth and growth on thermally sensitive materials, laser-assisted chemical vapour deposition (LCVD) can be applied advantageously. Here we report on the growth of single layers of pure Cr{sub 2}O{sub 3} onto sapphire substrates at room temperature by low pressure photolytic LCVD, using UV laser radiation and Cr(CO){sub 6} as chromium precursor. The feasibility of the LCVD technique to access selective area deposition of chromia thin films is demonstrated. Best results were obtained for a laser fluence of 120 mJ cm{sup -2} and a partial pressure ratio of O{sub 2} to Cr(CO){sub 6} of 1.0. Samples grown with these experimental parameters are polycrystalline and their microstructure is characterised by a high density of particles whose size follows a lognormal distribution. Deposition rates of 0.1 nm s{sup -1} and mean particle sizes of 1.85 {mu}m were measured for these films.

Stomatal acclimation to vapour pressure deficit doubles transpiration of small tree seedlings with warming

DEFF Research Database (Denmark)

Marchin, Renée M.; Broadhead, Alice A.; Bostic, Laura E.

2016-01-01

chamber VPD. Warming increased mean water use of Carya by 140% and Quercus by 150%, but had no significant effect on water use of Acer. Increased water use of ring-porous species was attributed to (1) higher air T and (2) stomatal acclimation to VPD resulting in higher gs and more sensitive stomata......Future climate change is expected to increase temperature (T) and atmospheric vapour pressure deficit (VPD) in many regions, but the effect of persistent warming on plant stomatal behaviour is highly uncertain. We investigated the effect of experimental warming of 1.9-5.1 °C and increased VPD of 0.......5-1.3 kPa on transpiration and stomatal conductance (gs ) of tree seedlings in the temperate forest understory (Duke Forest, North Carolina, USA). We observed peaked responses of transpiration to VPD in all seedlings, and the optimum VPD for transpiration (Dopt ) shifted proportionally with increasing...

Axial mercury segregation in direct current operated low-pressure argon-mercury gas discharges: Part I. Experimental

International Nuclear Information System (INIS)

Gielen, John W A M; Groot, Simon de; Mullen, Joost J A M van der

2004-01-01

Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally, axial luminance distributions have been measured which are converted into axial mercury vapour pressure distributions by an appropriate calibration method. The mercury segregation has been investigated for variations in lamp tube radius (3.6-4.8 mm), argon buffer gas pressure (200-600 Pa) and lamp current (100-250 mA) at mercury vapour pressures set at the anode in the range from 0.2 to 9.0 Pa. From the experiments it has been concluded that the mercury vapour pressure gradient at any axial position for a certain lamp tube diameter, argon pressure and lamp current depends on the local mercury vapour pressure. This observation is in contrast to assumptions made in earlier modelling publications in which one mercury vapour pressure gradient is used for all axial positions. By applying a full factorial design, an empirical relation of the mercury segregation is found for any set of parameters inside the investigated parameter ranges

Relationships of solar radiation and vapour pressure deficit with photosynthesis and water relations in dry-land pigeon pea

International Nuclear Information System (INIS)

Subramanian, V.B.; Venkateswarlu, S.; Maheswari, M.; Sankar, G.R.M.

1994-01-01

A study was undertaken to compare the relationships of photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) with carbon assimilation and water relations of dry-land pigeon pea at the vegetative and reproductive phases. Photosynthetic rate (Pn), transpiration rate (T), leaf water potential (wL), and stomatal conductance (gs) were measured at 7- to 10-day intervals from 1 month after seedling until a fortnight before harvest during two seasons. Generally, Pn, T, and gs were higher and wL was lower during the reproductive than during the vegetative phase. At high PAR and VPD, Pn, T, wL, and gs decreased. The decrease in the T at high PAR was smaller during the reproductive phase. Growth of dry-land pigeon pea was affected not only during periods of water stress which was associated with high PAR and high VPD but also under conditions of favourable plant water status which were associated with less than optimal levels of PAR. It also showed transpiration efficiency (TE) was lower during the pod-filling than during the vegetative phase, when PAR was optimum

Automated calibration of laser spectrometer measurements of δ18 O and δ2 H values in water vapour using a Dew Point Generator.

Science.gov (United States)

Munksgaard, Niels C; Cheesman, Alexander W; Gray-Spence, Andrew; Cernusak, Lucas A; Bird, Michael I

2018-06-30

Continuous measurement of stable O and H isotope compositions in water vapour requires automated calibration for remote field deployments. We developed a new low-cost device for calibration of both water vapour mole fraction and isotope composition. We coupled a commercially available dew point generator (DPG) to a laser spectrometer and developed hardware for water and air handling along with software for automated operation and data processing. We characterised isotopic fractionation in the DPG, conducted a field test and assessed the influence of critical parameters on the performance of the device. An analysis time of 1 hour was sufficient to achieve memory-free analysis of two water vapour standards and the δ 18 O and δ 2 H values were found to be independent of water vapour concentration over a range of ≈20,000-33,000 ppm. The reproducibility of the standard vapours over a 10-day period was better than 0.14 ‰ and 0.75 ‰ for δ 18 O and δ 2 H values, respectively (1 σ, n = 11) prior to drift correction and calibration. The analytical accuracy was confirmed by the analysis of a third independent vapour standard. The DPG distillation process requires that isotope calibration takes account of DPG temperature, analysis time, injected water volume and air flow rate. The automated calibration system provides high accuracy and precision and is a robust, cost-effective option for long-term field measurements of water vapour isotopes. The necessary modifications to the DPG are minor and easily reversible. Copyright © 2018 John Wiley & Sons, Ltd.

Thermal diffusion of water vapour in porous materials: fact or fiction?

DEFF Research Database (Denmark)

Janssen, Hans

2011-01-01

diffusion. Thermal diffusion opponents, on the other hand, assert that these thermal transports are negligibly small. This paper resolves that contradiction. A critical analysis of the investigations supporting the occurrence of thermal diffusion reveals that all are flawed. A correct reinterpretation...... its negligible magnitude. It can in conclusion be stated that thermal diffusion is of no importance for building science applications, leaving vapour pressure as the sole significant transport potential for the diffusion of water vapour in porous materials. (C) 2010 Elsevier Ltd. All rights reserved....

Isothermal (vapour + liquid) equilibrium for binary mixtures of polyethylene glycol mono-4-nonylphenyl ether (PEGNPE) with methanol, ethanol, or 2-propanol

International Nuclear Information System (INIS)

Khoiroh, Ianatul; Lee, Ming-Jer

2011-01-01

Highlights: → An autoclave apparatus was used for binary (vapour + liquid) equilibrium data measurement. → The studied systems are polyethylene glycol mono-4-nonylphenyl ether with alcohols. → The saturated pressure data were fitted accurately to the Antoine equation. → The NRTL model correlated well the phase equilibrium data. → The solvent activities have been calculated. - Abstract: Saturated pressures of three binary systems of oligomeric polyethylene glycol mono-4-nonylphenyl ether (PEGNPE) with methanol, ethanol, and 2-propanol have been measured by using an autoclave (vapour + liquid) equilibrium (VLE) apparatus at temperatures ranging from (340 to 455) K and the oligomer content ranging from 0.100 to 0.400 in mole fraction. With a given feed composition, equilibrium pressures were measured at various temperatures to obtain VLE data. The experimental data were fitted to the Antoine equation and also correlated with activity coefficient models, the NRTL and the UNIQUAC. The correlation results showed good agreement between the calculated values and the experimental data. In general, the NRTL model yielded better results. Additionally, the solvent activities were evaluated from the experimental results and were compared with those from the NRTL and the UNIQUAC models.

Initiation of a boiling liquid expanding vapour explosion

Energy Technology Data Exchange (ETDEWEB)

McDevitt, C.A.; Chan, C.K.; Steward, F.R.; Tennankore, K.N.; Venart, J.E.S.

1991-06-01

Boiling liquid expanding vapour explosions (BLEVEs) occur when a pressure liquefied gas tank is burst and the fluid is ejected to the atmosphere. As the liquid is exposed to a lower pressure it boils violently, causing an explosion which destroys the container. One litre tanks were filled with propane or R12, heated, and caused to rupture at specific test conditions to determine the parameters required for a BLEVE. Results showed that the energy stored in the liquid under pressure relative to the liquid at atmospheric conditions was a quantity which can be used to predict a BLEVE for the particular apparatus and conditions used. The possible importance of the development of a shock wave within the container during a BLEVE was noted. A shock tube was used to study the shock waves generated during a BLEVE. Temperature, liquid volume, rupture location, rupture area, and the fluid involved were varied. The pressure was measured vs time for periods immediately after the rupture. Photographs of the formation of pressure waves were obtained using spark Schlieren photography and showed that the BLEVE phenomenon is definitely a shock-related event. Pressure information was also gathered during BLEVEs of one litre cylinders, and this information is compared to that from the shock tube. Shock tube data showed that transverse waves formed from the initial pressure wave could be amplified. 37 refs., 54 figs., 11 tabs.

The precise measurement of the (vapour + liquid) equilibrium properties for (CO2 + isobutane) binary mixtures

International Nuclear Information System (INIS)

Nagata, Y.; Mizutani, K.; Miyamoto, H.

2011-01-01

Recently, it has been suggested that natural working fluids, such as CO 2 , hydrocarbons, and their mixtures, could provide a long-term alternative to fluorocarbon refrigerants. (Vapour + liquid) equilibrium (VLE) data for these fluids are essential for the development of equations of state, and for industrial process such as separation and refinement. However, there are large inconsistencies among the available literature data for (CO 2 + isobutane) binary mixtures, and therefore provision of reliable and new measurements with expanded uncertainties is required. In this study, we determined precise VLE data using a new re-circulating type apparatus, which was mainly designed by Akico Co., Japan. An equilibrium cell with an inner volume of about 380 cm 3 and two optical windows was used to observe the phase behaviour. The cell had re-circulating loops and expansion loops that were immersed in a thermostatted liquid bath and air bath, respectively. After establishment of a steady state in these loops, the compositions of the samples were measured by a gas chromatograph (GL Science, GC-3200). The VLE data were measured for CO 2 /propane and CO 2 /isobutane binary mixtures within the temperature range from 300 K to 330 K and at pressures up to 7 MPa. These data were compared with the available literature data and with values predicted by thermodynamic property models.

Numerical Analysis of Flow and Heat Transfer Characteristics of CO2 at Vapour and Supercritical Phases in Micro-Channels

Directory of Open Access Journals (Sweden)

Rao N.T.

2016-01-01

Full Text Available Supercritical carbon dioxide (CO2 has special thermal properties with better heat transfer and flow characteristics. Due to this reason, supercritical CO2 is being used recently in air-condition and refrigeration systems to replace non environmental friendly refrigerants. Even though many researches have been done, there are not many literatures for heat transfer and flow characteristics of supercritical CO2. Therefore, the main purpose of this study is to develop flow and heat transfer CFD models on two different phases; vapour and supercritical of CO2 to investigate the heat transfer characteristics and pressure drop in micro-channels. CO2 is considered to be in different phases with different flow pressures but at same temperature. For the simulation, the CO2 flow was assumed to be turbulent, nonisothermal and Newtonian. The numerical results for both phases are compared. From the numerical analysis, for both vapour and supercritical phases, the heat energy from CO2 gas transferred to water to attain thermal equilibrium. The temperature of CO2 at vapour phase decreased 1.78% compared to supercritical phase, which decreased for 0.56% from the inlet temperature. There was a drastic increase of 72% for average Nu when the phase changed from vapour to supercritical. The average Nu decreased rapidly about 41% after total pressure of 9.0 MPa. Pressure drop (ΔP increased together with Reynolds number (Re for vapour and supercritical phases. When the phase changed from vapour to supercritical, ΔP was increased about 26%. The results obtained from this study can provide information for further investigations on supercritical CO2.

Diffusion and flow of water vapours in chromatographic Alumina gel

International Nuclear Information System (INIS)

Khan, M.; Shah, H. U.

2005-01-01

The kinetics of sorption of water vapours in chromatographic alumina gel was studied. Water vapours are adsorbed on the gel at temperature (15 degree C) at different constant relative pressure from 0.1-0.93 p/p. Rate constant, Effective diffusivities, Knudsen diffusivities and bulk diffusivities were determined through Fick type equation. Total pore volume is 0.498 cc g-1 and specific surface area comes to be 465 m2 g-1 as obtained by Gurvitsch rule and Kieselve's quantities respectively. An average pore radius (hydraulic) is 1.1x10/sub -7/ cm. The study of these quantities provide a strong basis for evaluating surface properties. (author)

Vapour loss (``boiling'') as a mechanism for fluid evolution in metamorphic rocks

Science.gov (United States)

Trommsdorff, Volkmar; Skippen, George

1986-11-01

The calculation of fluid evolution paths during reaction progress is considered for multicomponent systems and the results applied to the ternary system, CO2-H2O-NaCl. Fluid evolution paths are considered for systems in which a CO2-rich phase of lesser density (vapour) is preferentially removed from the system leaving behind a saline aqueous phase (liquid). Such “boiling” leads to enrichment of the residual aqueous phase in dissolved components and, for certain reaction stoichiometries, to eventual saturation of the fluids in salt components. Distinctive textures, particularly radiating growths of prismatic minerals such as tremolite or diopside, are associated with saline fluid inclusions and solid syngenetic salt inclusions at a number of field localities. The most thoroughly studied of these localities is Campolungo, Switzerland, where metasomatic rocks have developed in association with fractures and veins at 500° C and 2,000 bars of pressure. The petrography of these rocks suggests that fluid phase separation into liquid and vapour has been an important process during metasomatism. Fracture systems with fluids at pressure less than lithostatic may facilitate the loss of the less dense vapour phase to conditions of the amphibolite facies.

Evaluation of niobium dimethylamino-ethoxide for chemical vapour deposition of niobium oxide thin films

International Nuclear Information System (INIS)

Dabirian, Ali; Kuzminykh, Yury; Wagner, Estelle; Benvenuti, Giacomo; Rushworth, Simon; Hoffmann, Patrik

2014-01-01

Chemical vapour deposition (CVD) processes depend on the availability of suitable precursors. Precursors that deliver a stable vapour pressure are favourable in classical CVD processes, as they ensure process reproducibility. In high vacuum CVD (HV-CVD) process vapour pressure stability of the precursor is of particular importance, since no carrier gas assisted transport can be used. The dimeric Nb 2 (OEt) 10 does not fulfil this requirement since it partially dissociates upon heating. Dimethylamino functionalization of an ethoxy ligand of Nb(OEt) 5 acts as an octahedral field completing entity and leads to Nb(OEt) 4 (dmae). We show that Nb(OEt) 4 (dmae) evaporates as monomeric molecule and ensures a stable vapour pressure and, consequently, stable flow. A set of HV-CVD experiments were conducted using this precursor by projecting a graded molecular beam of the precursor onto the substrate at deposition temperatures from 320 °C to 650 °C. Film growth rates ranging from 8 nm·h −1 to values larger than 400 nm·h −1 can be obtained in this system illustrating the high level of control available over the film growth process. Classical CVD limiting conditions along with the recently reported adsorption–reaction limited conditions are observed and the chemical composition, and microstructural and optical properties of the films are related to the corresponding growth regime. Nb(OEt) 4 (dmae) provides a large process window of deposition temperatures and precursor fluxes over which carbon-free and polycrystalline niobium oxide films with growth rates proportional to precursor flux are obtained. This feature makes Nb(OEt) 4 (dmae) an attractive precursor for combinatorial CVD of niobium containing complex oxide films that are finding an increasing interest in photonics and photoelectrochemical water splitting applications. The adsorption–reaction limited conditions provide extremely small growth rates comparable to an atomic layer deposition (ALD) process

Electron drift velocities in He and water mixtures: Measurements and an assessment of the water vapour cross-section sets

International Nuclear Information System (INIS)

Urquijo, J. de; Juárez, A. M.; Basurto, E.; Ness, K. F.; Robson, R. E.; White, R. D.; Brunger, M. J.

2014-01-01

The drift velocity of electrons in mixtures of gaseous water and helium is measured over the range of reduced electric fields 0.1–300 Td using a pulsed-Townsend technique. Admixtures of 1% and 2% water to helium are found to produce negative differential conductivity (NDC), despite NDC being absent from the pure gases. The measured drift velocities are used as a further discriminative assessment on the accuracy and completeness of a recently proposed set of electron-water vapour cross-sections [K. F. Ness, R. E. Robson, M. J. Brunger, and R. D. White, J. Chem. Phys. 136, 024318 (2012)]. A refinement of the momentum transfer cross-section for electron-water vapour scattering is presented, which ensures self-consistency with the measured drift velocities in mixtures with helium to within approximately 5% over the range of reduced fields considered

Medium scale fire tests of propane tanks to study the boiling liquid expanding vapour explosion (BLEVE) and transient two-phase jet release

Energy Technology Data Exchange (ETDEWEB)

Ye Zhifei

1994-07-01

A series of medium scale fire tests were conducted to study boiling liquid expanding vapour explosions (BLEVE) and transient jet releases resulting from thermally induced propane tank ruptures. The tests were conducted using commercial propane contained in automotive propane tanks with a capacity of ca 400 liters. The tanks were brought to failure using a combination of torch and pool fire impingement. Instrumentation was included to measure internal pressure, liquid, vapour and wall temperature distribution, tank and lading mass, external blast overpressure, and fireball thermal radiation. Video and still cameras were used to record the fireball and jet fire shapes and dimensions. Two different kinds of BLEVE failure were observed. For very weak tanks the BLEVE was a single step process where the rupture propagated rapidly along the length of the tank. The duration of these events was measured in milliseconds and it is suggested that the process is driven by the vapour space energy. The other type of BLEVE was a two step process where a crack would start in a weakened area, arrest in a stronger part of the tank, and then start again to end in catastrophic failure. Initial failure and jet type release results in violent boiling and pressure recovery in the tank, leading to restart of the crack and catastrophic failure. Time duration is measured in seconds, and is driven by energy stored in the liquid. A computer model was developed to simulate the transient jet release resulting from finite tank failures, and can predict transient mass flow, tank pressure decay, visible flame length and jet fire thermal radiation. 253 refs., 132 figs., 29 tabs.

Experimental determination of the isothermal (vapour + liquid) equilibria of binary aqueous solutions of sec-butylamine and cyclohexylamine at several temperatures

Energy Technology Data Exchange (ETDEWEB)

Chiali-Baba Ahmed, Nouria [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, Post Office Box 119, Tlemcen 13000 (Algeria); Negadi, Latifa, E-mail: latifanegadi@yahoo.fr [LATA2M, Laboratoire de Thermodynamique Appliquee et Modelisation Moleculaire, University AbouBekr Belkaid of Tlemcen, Post Office Box 119, Tlemcen 13000 (Algeria); Mokbel, Ilham [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5280, Universite Claude Bernard - Lyon I, 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France); Kaci, Ahmed Ait [Laboratoire de Thermodynamique et Modelisation Moleculaire, Universite des Sciences et de la Technologie Houari Boumediene, Post Office Box 32, El Alia 16111, Bab Ezzouar (Algeria); Jose, Jacques [LSA, Laboratoire des Sciences Analytiques, CNRS-UMR 5280, Universite Claude Bernard - Lyon I, 43, Bd du 11 Novembre 1918, Villeurbanne Cedex 69622 (France)

2012-01-15

Highlights: > Vapour pressures of sec-butylamine or cyclohexylamine and their aqueous solutions. > The investigated temperatures are 273 K and 363 K. > The (cyclohexylamine + water) mixture shows positive azeotropic behaviour. > The (sec-butylamine + water) or (cyclohexylamine + water) exhibit positive G{sup E}. - Abstract: The vapour pressures of (sec-butylamine + water), (cyclohexylamine + water) binary mixtures, and of pure sec-butylamine and cyclohexylamine components were measured by means of two static devices at temperatures between 293 (or 273) K and 363 K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (G{sup E}) were calculated for several constant temperatures and fitted to a fourth-order Redlich-Kister equation using the Barker's method. The (cyclohexylamine + water) system shows positive azeotropic behaviour for all investigated temperatures. The two binary mixtures exhibit positive deviations in G{sup E} for all investigated temperatures over the whole composition range.

Comparisons of xylem sap flow and water vapour flux at the stand level and derivation of canopy conductance for Scots pine

Science.gov (United States)

Granier, A.; Biron, P.; Köstner, B.; Gay, L. W.; Najjar, G.

1996-03-01

Simultaneous measurements of xylem sap flow and water vapour flux over a Scots pine ( Pinus sylvestris) forest (Hartheim, Germany), were carried out during the Hartheim Experiment (HartX), an intensive observation campaign of the international programme REKLIP. Sap flow was measured every 30 min using both radial constant heating (Granier, 1985) and two types of Cermak sap flowmeters installed on 24 trees selected to cover a wide range of the diameter classes of the stand (min 8 cm; max 17.5 cm). Available energy was high during the observation period (5.5 to 6.9 mm.day-1), and daily cumulated sap flow on a ground area basis varied between 2.0 and 2.7 mm day-1 depending on climate conditions. Maximum hourly values of sap flow reached 0.33 mm h-1, i.e., 230 W m-2. Comparisons of sap flow with water vapour flux as measured with two OPEC (One Propeller Eddy Correlation, University of Arizona) systems showed a time lag between the two methods, sap flow lagging about 90 min behind vapour flux. After taking into account this time lag in the sap flow data set, a good agreement was found between both methods: sap flow = 0.745* vapour flux, r 2 = 0.86. The difference between the two estimates was due to understory transpiration. Canopy conductance ( g c ) was calculated from sap flow measurements using the reverse form of Penman-Monteith equation and climatic data measured 4 m above the canopy. Variations of g c were well correlated ( r 2 = 0.85) with global radiation ( R) and vapour pressure deficit ( vpd). The quantitative expression for g c = f ( R, vpd) was very similar to that previously found with maritime pine ( Pinus pinaster) in the forest of Les Landes, South Western France.

Airborne differential absorption lidar for water vapour measurements in the upper troposphere and lower stratosphere in the spectral region around 940 nm

Energy Technology Data Exchange (ETDEWEB)

Poberaj, G.

2000-07-01

Two all-solid-state laser systems were developed and studied in detail to optimise their performance for an airborne water vapour differential absorption lidar (DIAL). Their special features are high average output powers and excellent spectral properties in the 940-nm spectral region relevant for monitoring very low water vapour contents in the upper troposphere and lower stratosphere. One system is an injection-seeded pulsed Ti:sapphire ring laser with a spectral bandwidth of 105 MHz and an average power of 1.1 W. The other system is an injection-seeded optical parametric oscillator (OPO) in a ring configuration. Using KTP as nonlinear crystal, a signal output with a spectral bandwidth of 140 MHz and an average power of 1.2 W was achieved. Both systems, the Ti:sapphire ring laser and the KTP OPO, possess spectral purity values higher than 99%. The pump source for these systems is a frequency doubled diode-pumped Nd:YAG laser operating at a repetition rate of 100 Hz. The KTP OPO system has been used as a transmitter in a new airborne water vapour DIAL instrument. For the first time, measurements of two-dimensional water vapour distributions with a high vertical (500 m) and horizontal (20 km) resolution across several potential vorticity streamers were performed. Very low water vapour mixing ratios (10-50 ppmv) and strong gradients were observed in the tropopause region. The sensitivity of the DIAL instrument in the centre of a stratospheric intrusion ranges from 3% in the near field to 12% in the far field (4 km). The first comparison experiments with in situ measuring instruments show a good agreement. Considerable differences are found between DIAL measurements and data obtained from the ECMWF operational analyses and a mesoscale numerical model. (orig.)

Electron collision cross section sets of TMS and TEOS vapours

Science.gov (United States)

Kawaguchi, S.; Takahashi, K.; Satoh, K.; Itoh, H.

2017-05-01

Reliable and detailed sets of electron collision cross sections for tetramethylsilane [TMS, Si(CH3)4] and tetraethoxysilane [TEOS, Si(OC2H5)4] vapours are proposed. The cross section sets of TMS and TEOS vapours include 16 and 20 kinds of partial ionization cross sections, respectively. Electron transport coefficients, such as electron drift velocity, ionization coefficient, and longitudinal diffusion coefficient, in those vapours are calculated by Monte Carlo simulations using the proposed cross section sets, and the validity of the sets is confirmed by comparing the calculated values of those transport coefficients with measured data. Furthermore, the calculated values of the ionization coefficient in TEOS/O2 mixtures are compared with measured data to confirm the validity of the proposed cross section set.

Ethanol vapour induced dilated cardiomyopathy in chick embryos

International Nuclear Information System (INIS)

Kamran, K.; Khan, M.Y.; Minhas, L.A.

2013-01-01

Objective: To study the effects of ethanol vapour inhalation on the heart chambers of chick embryo. Methods: The case-control study was conducted at the College of Physicians and Surgeons Pakistan regional centre in Islamabad from January to October 2007. Both experimental and control groups were divided into three sub-groups each, based on the day of the sacrifice. Each group was dissected on day 7, day 10 and day 22 or hatching whichever was earlier. The experimental sub-groups sacrificed on day 7, day 10 and on hatching, were exposed to ethanol vapours till day 6, 9 and 9 of incubation respectively. The diameter of all 4 chambers was measured in experimental hearts and compared with age-matched controls. SPSS 10 was used for statistical analysis. Results: Ethanol vapour exposure caused widening of all heart chambers in the experimental chick embryos sacrificed on day 7 and day 10 compared to the controls. The chambers of newly hatched chick hearts showed dilatation in all the chambers except the left ventricle. Conclusion: Ethanol vapour exposure during development affects the heart, resulting in the widening of all heart chambers. The exposure is as dangerous as drinking alcohol. Alcohol vapour exposure during development leads to progressive dilatation in different heart chambers, producing dilated cardiomyopathy. (author)

Evolution of stratospheric ozone and water vapour time series studied with satellite measurements

Directory of Open Access Journals (Sweden)

A. Jones

2009-08-01

Full Text Available The long term evolution of stratospheric ozone and water vapour has been investigated by extending satellite time series to April 2008. For ozone, we examine monthly average ozone values from various satellite data sets for nine latitude and altitude bins covering 60° S to 60° N and 20–45 km and covering the time period of 1979–2008. Data are from the Stratospheric Aerosol and Gas Experiment (SAGE I+II, the HALogen Occultation Experiment (HALOE, the Solar BackscatterUltraViolet-2 (SBUV/2 instrument, the Sub-Millimetre Radiometer (SMR, the Optical Spectrograph InfraRed Imager System (OSIRIS, and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY. Monthly ozone anomalies are calculated by utilising a linear regression model, which also models the solar, quasi-biennial oscillation (QBO, and seasonal cycle contributions. Individual instrument ozone anomalies are combined producing an all instrument average. Assuming a turning point of 1997 and that the all instrument average is represented by good instrumental long term stability, the largest statistically significant ozone declines (at two sigma from 1979–1997 are seen at the mid-latitudes between 35 and 45 km, namely −7.2%±0.9%/decade in the Northern Hemisphere and −7.1%±0.9%/in the Southern Hemisphere. Furthermore, for the period 1997 to 2008 we find that the same locations show the largest ozone recovery (+1.4% and +0.8%/decade respectively compared to other global regions, although the estimated trend model errors indicate that the trend estimates are not significantly different from a zero trend at the 2 sigma level. An all instrument average is also constructed from water vapour anomalies during 1991–2008, using the SAGE II, HALOE, SMR, and the Microwave Limb Sounder (Aura/MLS measurements. We report that the decrease in water vapour values after 2001 slows down around 2004–2005 in the lower tropical stratosphere (20–25 km and has even

Hydrogen production by the iodine-sulphur thermochemical cycle. Total and partial pressure measurements

International Nuclear Information System (INIS)

D Doizi; V Dauvois; J L Roujou; V Delanne; P Fauvet; B Larousse; O Hercher; P Carles; C Moulin

2006-01-01

The iodine sulphur thermochemical cycle appears to be one of the most promising candidate for the massive production of hydrogen using nuclear energy. The key step in this cycle is the HI distillation section which must be optimized to get a good efficiency of the overall cycle. The concept of reactive versus extractive distillation of HI has been proposed because of its potentiality. The design and the optimization of the reactive distillation column requires the knowledge of the liquid vapour equilibrium over the ternary HI-I 2 -H 2 O mixtures up to 300 C and 100 bars. A general methodology based on three experimental devices imposed by the very corrosive and concentrated media will be described: 1) I1 for the total pressure measurement versus different ternary compositions. 2) I2 for the partial and total pressure measurements around 130 C and 2 bars to validate the choice of the analytical optical 'online' techniques we have proposed. 3) I3 for the partial and total pressures measurements in the process domain. The results obtained on pure samples, binary mixtures HI-H 2 O and ternary mixtures using an experimental design analysis in the experimental device I2 will be discussed. (authors)

Waves reflected by solid wall and wave interaction in vapour bubbly liquids

International Nuclear Information System (INIS)

Duong, N.H.; Nguyen, V.T.

2004-01-01

The vapour bubbly liquids are met in many natural and industrial processes, including in energy equipment. In the nuclear power plants this kind of medium appears in reactor cores (PWR, BWR and etc.), in turbine generators and in heat transfer loops. Due to some circumstances (for example, a hit caused by detonations or strong collisions) the pressure waves can appear in the bubbly liquid medium contained in those facilities. These waves propagate in the mixtures and interact with themselves and with structures. It is important that what will occur during mentioned above processes. The knowledge of this kind processes will be useful for analysing the different sorts of the processes occurred in the energy facilities where the vapor bubbly liquids are used as working or heat transfer medium, like nuclear power plants, and also useful in finding the measures for prevention of unfavourable phenomena (for example, during wave interactions maybe appear too high pressures, which could lead into damages of facilities and etc.) and safety operating the equipment. From the physical point of view, the waves in this kind of medium are interesting that owing to non-linear, dispersion and dissipation effects the wave patterns in them may be diverse and easy altered. In the paper the investigation results of the waves reflected by solid wall or structure of the moderate intensity shock waves, and the behaviour of pressure in the process of wave interaction in some mixtures of liquid with vapour bubbles (of radium ∼1 mm) are presented. (author)

Isothermal (vapour + liquid) equilibrium data for binary systems of (n-hexane + CO2 or CHF3)

International Nuclear Information System (INIS)

Williams-Wynn, Mark D.; Naidoo, Paramespri; Ramjugernath, Deresh

2016-01-01

Highlights: • (Static-analytic + static-synthetic) phase equilibrium measurements. • Binary VLE data for (CO 2 + n-hexane) and (trifluoromethane + n-hexane). • Thermodynamic models were fitted to the experimental data. • Liquid–liquid immiscibility occurred with (trifluoromethane + n-hexane) system. - Abstract: The (vapour + liquid) equilibrium (VLE) was measured for the (carbon dioxide + n-hexane) binary system at temperatures between T = (303.1 and 323.1) K. In addition, VLE and (vapour + liquid + liquid) equilibria (VLLE) were determined for the (trifluoromethane + n-hexane) binary system at temperatures between T = (272.9 and 313.3) K and pressures in the range of P = (1.0 to 5.7) MPa. Measurements were undertaken in a static-analytic apparatus, with verification of experimental values undertaken using a static-synthetic equilibrium cell to measure bubble point pressures at several compositions. The phase equilibrium results were modelled with the Peng–Robinson equation of state with the Mathias–Copeman alpha function, coupled with the Wong–Sandler mixing rules. Regression of the data was performed with the NRTL and the UNIQUAC activity coefficient models with the Wong–Sandler mixing rules, and the performance of the models was compared. Critical loci for both systems were estimated, using the calculation procedures of Ungerer et al. and Heidemann and Khalil. For the (trifluoromethane + n-hexane) system, liquid–liquid immiscibility was experienced at the lowest temperature measured (T = 272.9 K). At higher temperatures, no immiscibility was visible during the measurements; however, the models continued to predict a miscibility gap.

Vapour galvanizing (Sherardizing) of copper with zinc

Energy Technology Data Exchange (ETDEWEB)

Wortelen, Dietbert; Bracht, Hartmut [Westfaelische Wilhelms-Universitaet Muenster (Germany); Natrup, Frank; Graf, Wolfram [Bodycote Waermebehandlung GmbH, Sprockhoevel (Germany)

2010-07-01

Using a vapour galvanizing technique called Sherardizing we investigated the growth kinetics and coefficients of zinc copper phases. For this purpose polished (OFHC)-copper plates and zinc powder have been sealed in quartz ampoules under inert gas atmospheres and annealed at a temperature range between 300 and 410 C. In order to study the coating thickness and the phase composition, cross sections were prepared, which have been analyzed by means of optical microscopy and scanning electron microscopy. We were able to demonstrate that the coating thickness is a function of the parabolic time law and that the formed coatings are composed of two layers referring to the ordered {beta}-CuZn and {gamma}-Cu{sub 5}Zn{sub 8}-phases. To enhance the coating quality, small amounts of ZnCl{sub 2} were added to the zinc powder. It was observed that the coating thickness decreased with increasing ZnCl{sub 2}. Experiments with variable Ar-pressure demonstrated a reduced coating growth with increasing pressures. Further measurements with ZnCl{sub 2} were performed to check whether an electrochemical mechanism is involved in the coating process.

The Droplets Condensate Centering in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

Science.gov (United States)

Seryakov, A. V.; Shakshin, S. L.; Alekseev, A. P.

2017-11-01

The results of experimental studies of the process of condensate microdroplets centering contained in the moving moist vapour in the vapour channel of short heat pipes (HPs) for large thermal loads are presented. A vapour channel formed by capillary-porous insert in the form of the inner Laval-liked nozzle along the entire length of the HP. In the upper cover forming a condensation surface in the HP, on the diametrical line are installed capacitive sensors, forming three capacitors located at different distances from the longitudinal axis of the vapour channel. With increasing heat load and the boil beginning in the evaporator a large amount of moist vapour in the vapour channel of HP occur the pressure pulsation with frequency of 400-500 Hz and amplitude up to 1·104Pa. These pulsations affect the moving of the inertial droplets subsystem of the vapour and due to the heterogeneity of the velocity profile around the particle flow in the vapour channel at the diameter of microdroplets occurs transverse force, called the Saffman force and shear microdroplets to the center of vapour channel. Using installed in the top cover capacitors we can record the radial displacement of the condensable microdroplets.

Volatility of coal liquids at high temperatures and pressures

Energy Technology Data Exchange (ETDEWEB)

Wilson, G M; Johnston, R H; Hwang, S C; Tsonopoulos, C

1981-01-01

The volatility of coal liquids has been experimentally determined at 700-880 F and about 2000 psia. These measurements were made in a flow apparatus to minimize thermal decomposition effects at high temperatures. Three coal liquids in mixture with Hat2, methane, and Hat2S were investigated. Measurements were also made up to 900 F on the vapor pressure of pure compounds found in coal liquids and on the equilibrium pressure of narrow coal liquid cuts. These data were used to develop a new method for the prediction of the critical point and the superatmospheric vapour pressures of aromatic fractions that is superior to the Maxwell-Bonnell correlation. The VLE data on coal liquids and some recent high-temperature VLE data on binaries of aromatics with Hat2 or methane were analyzed with a modified Chao-Seader correlation and a modified Redlich-Kwong equation of state. Both VLE correlations are shown to be equivalent in the prediction of the volatility of coal liquids, when the new vapour pressure procedure is used.

Atmospheric pressure chemical vapour deposition of vanadium arsenide thin films via the reaction of VCl4 or VOCl3 with tBuAsH2

International Nuclear Information System (INIS)

Thomas, Tegan; Blackman, Christopher S.; Parkin, Ivan P.; Carmalt, Claire J.

2013-01-01

Thin films of vanadium arsenide were deposited via the dual-source atmospheric pressure chemical vapour deposition reactions of VCl 4 or VOCl 3 with t BuAsH 2 . Using the vanadium precursor VCl 4 , films were deposited at substrate temperatures of 550–600 °C, which were black-gold in appearance and were found to be metal-rich with high levels of chlorine incorporation. The use of VOCl 3 as the vanadium source resulted in films being deposited between 450 and 600 °C and, unlike when using VCl 4 , were silver in appearance. The films deposited using VOCl 3 demonstrated vanadium to arsenic ratios close to 1:1, and negligible chlorine incorporation. Films deposited using either vanadium precursor were identified as VAs using powder X-ray diffraction and possessed borderline metallic/semiconductor resistivities. - Highlights: • Formation of VAs films via atmospheric pressure chemical vapour deposition. • Films formed using VCl 4 or VOCl 3 and t BuAsH 2 . • Powder X-ray diffraction showed that crystalline VAs films were deposited. • Films from VOCl 3 had a V:As ratio close to 1 with negligible Cl incorporation. • Films were silver and possessed borderline metallic/semiconductor resistivities

High-pressure phase equilibria in the (carbon dioxide + 1-hexanol) system

International Nuclear Information System (INIS)

Secuianu, Catinca; Feroiu, Viorel; Geana, Dan

2010-01-01

(Vapour + liquid) equilibria (VLE) and (vapour + liquid + liquid) equilibria (VLLE) data for the (carbon dioxide + 1-hexanol) system were measured at (293.15, 303.15, 313.15, 333.15, and 353.15) K. Phase behaviour measurements were made in a high-pressure visual cell with variable volume, based on the static-analytic method. The pressure range under investigation was between (0.6 and 14.49) MPa. The Soave-Redlich-Kwong (SRK) equation of state (EOS) with classical van der Waals mixing rules (two-parameters conventional mixing rule, 2PCMR), was used in a semi-predictive approach, in order to represent the complex phase behaviour (critical curve, LLV line, isothermal VLE, LLE, and VLLE) of the system. The topology of phase behaviour is reasonably well predicted.

The Liquid Vapour Interface

DEFF Research Database (Denmark)

Als-Nielsen, Jens Aage

1985-01-01

In this short review we are concerned with the density variation across the liquid-vapour interface, i.e. from the bulk density of the liquid to the essentially zero density of the vapour phase. This density variation can in principle be determined from the deviation of the reflectivity from...

Isothermal phase (vapour + liquid) equilibrium data for binary mixtures of propene (R1270) with either 1,1,2,3,3,3-hexafluoro-1-propene (R1216) or 2,2,3-trifluoro-3-(trifluoromethyl)oxirane in the temperature range of (279 to 318) K

International Nuclear Information System (INIS)

Subramoney, Shalendra Clinton; Nelson, Wayne Michael; Courtial, Xavier; Naidoo, Paramespri; Coquelet, Christophe; Richon, Dominique; Ramjugernath, Deresh

2015-01-01

Highlights: • Phase equilibrium data for propene and hexafluoropropylene. • Phase equilibrium data for propene and hexafluoropropylene oxide. • Systems exhibit pressure-maximum azeotropes. • Data well correlated by Peng–Robinson equation of state with the Wong–Sandler mixing rule. - Abstract: Isothermal (vapour + liquid) equilibrium data (P–x–y) are presented for the 1-propene 1,1,2,3,3,3-hexafluoro-1-propene and the 1-propene + 2,2,3-trifluoro-3-(trifluoromethyl)oxirane binary systems. Both binary systems were studied at five temperatures, ranging from (279.36 to 318.09) K, at pressures up to 2 MPa. The experimental (vapour + liquid) equilibrium data were measured using an apparatus based on the “(static + analytic)” method incorporating a single movable Rapid On-Line Sampler-Injector to sample the liquid and vapour phases at equilibrium. The expanded uncertainties are approximated on average as T = 0.07 K, 0.008 MPa, and 0.007 and 0.009 for the temperature, pressure, and the liquid and vapour mole fractions, respectively. A homogenous maximum-pressure azeotrope was observed for both binary systems at all temperatures studied. The experimental data were correlated with the Peng–Robinson equation of state using the Mathias–Copeman alpha function, paired with the Wong–Sandler mixing rule and the Non-Random Two Liquid activity coefficient model. The model provided satisfactory representation of the phase equilibrium data measured

Technical committee meeting on aerosol formation, vapour deposits and sodium vapour trapping. Summary report

Energy Technology Data Exchange (ETDEWEB)

NONE

1977-01-01

The papers presented at the LMFBR meeting on aerosol formation covered the following four main topics: theoretical studies on aerosol behaviour and comparison with experimental results; techniques for measurement of aerosols; techniques for trapping sodium vapour and aerosols in gas circuits; design of components having to cope with aerosol deposits. The resulting summaries, conclusions and recommendations which were were agreed upon are presented.

Technical committee meeting on aerosol formation, vapour deposits and sodium vapour trapping. Summary report

International Nuclear Information System (INIS)

1977-01-01

The papers presented at the LMFBR meeting on aerosol formation covered the following four main topics: theoretical studies on aerosol behaviour and comparison with experimental results; techniques for measurement of aerosols; techniques for trapping sodium vapour and aerosols in gas circuits; design of components having to cope with aerosol deposits. The resulting summaries, conclusions and recommendations which were were agreed upon are presented

Sound speed of isobaric heat capacity in the saturated and superheated vapour of cesium, rubidium and potassium

International Nuclear Information System (INIS)

Novikov, I.I.; Roschupkin, V.V.

1985-01-01

The paper reviews the work carried out on the thermodynamic properties of alkali metal vapours. The most systematic investigations concern the sound velocity measurements for saturated and superheated vapours of caesium, for saturated vapour of rubidium, and for superheated vapour of potassium. The Joule-Thompson coefficient has been studied in caesium vapour, and the isobaric heat capacity of potassium vapour has also been examined. The experimental methods for all these experiments are described, and the data obtained are presented in tabular form. (U.K.)

Photosynthetic traits of five neotropical rainforest tree species: interactions between light response curves and leaf-to-air vapour pressure deficit

Directory of Open Access Journals (Sweden)

Marcelo Schramm Mielke

2005-09-01

Full Text Available Measurements of leaf gas exchange at different photosynthetic photon flux density (PPFD levels were conducted in order to compare the photosynthetic traits of five neotropical rainforest tree species, with a special emphasis on empirical mathematical models to estimate the light response curve parameters incorporating the effects of leaf-to-air vapour pressure deficit (D on the saturated photosynthetic rate (Amax. All empirical mathematical models seemed to provide a good estimation of the light response parameters. Comparisons of the leaf photosynthetic traits between different species needed to select an appropriate model and indicated the microenvironmental conditions when the data were collected. When the vapour pressure deficit inside the chamber was not controlled, the incorporation of linear or exponencial functions that explained the effects of D on leaf gas exchange, was a very good method to enhance the performance of the models.Medições das trocas gasosas foliares em diferentes níveis do densidade de fluxo de fótons fotossintéticamente ativos (PPFD foram realizadas com o objetivo de comparar as características fotossintéticas de cinco espécies arbóreas de florestas úmidas neotropicais, com especial ênfase em modelos matemáticos empíricos para estimativa de parâmetros derivados das curvas de resposta à radiação luminosa e dos efeitos da diferença de pressão de vapor entre a folha e o ar (D na taxa fotossintética em saturação luminosa (Amax. Os modelos analisados proporcionaram boas estimativas para os parâmetros derivados das curvas de resposta à radiação luminosa. Comparações entre as características fotossintéticas de diferentes espécies devem sempre considerar os modelos utilizados, seguidas de indicações pormenorizadas das condições microambientais no momento em que os dados foram coletados. Quando a diferença de pressão de vapor não for controlada artificialmente durante as medições, a

Theoretical calculations of primary particle condensation for cadmium and caesium iodide vapours

Energy Technology Data Exchange (ETDEWEB)

Buckle, E.R. [Division of Metallurgy, School of Materials, The University, Mappin Street, Sheffield S1 3JD (United Kingdom); Bowsher, B.R. [Chemistry Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1988-10-15

A theoretical approach to modelling aerosol nucleation from the vapour phase has been developed by Buckle. In this theory, the condensing vapour species are assumed to be transported from an evaporating source across a one-dimensional stagnant boundary layer into an unreactive vapour-free atmosphere. A slip-flow model for interfacial energy and mass flow is combined with this stagnant boundary layer model to yield a set of parameters that uniquely characterise the evaporative flow process (i.e. pressure, source and sink temperatures, sink concentration, and the flux density of heat or mass from the source). To obtain the initial conditions for nucleation the vapour saturation ratio p/p deg is plotted against temperature and compared with the minimum saturation ratio defined by homogeneous nucleation theory. The co-education be represented by a nucleation threshold (or F) diagram. The mass and energy equations of the flow are solved by introducing the Becker-Doering formula for the nucleation rate, and the Stefan diffusion model for particle growth. This gives the rise and fall of supersaturation and the evolution of the particle size distribution along the flow coordinate. In the present studies, the applicability of the model has been tested by considering the condensation of caesium iodide and cadmium vapours under a wide variety of pre-mixed flow conditions of interest to PWR severe accident studies. The model has been used to predict the onset of nucleation and the particle size distribution for single vapour species. Preliminary studies have demonstrated that conditions exist whereby both heterogeneous and homogeneous nucleation can occur simultaneously. This process could account for experimental observations of chemically-different aerosols being formed under severe reactor accident conditions. (author)

Continuous measurements of stable isotopes of carbon dioxide and water vapour in an urban atmosphere: isotopic variations associated with meteorological conditions.

Science.gov (United States)

Wada, Ryuichi; Matsumi, Yutaka; Nakayama, Tomoki; Hiyama, Tetsuya; Fujiyoshi, Yasushi; Kurita, Naoyuki; Muramoto, Kenichiro; Takanashi, Satoru; Kodama, Naomi; Takahashi, Yoshiyuki

2017-12-01

Isotope ratios of carbon dioxide and water vapour in the near-surface air were continuously measured for one month in an urban area of the city of Nagoya in central Japan in September 2010 using laser spectroscopic techniques. During the passages of a typhoon and a stationary front in the observation period, remarkable changes in the isotope ratios of CO 2 and water vapour were observed. The isotope ratios of both CO 2 and water vapour decreased during the typhoon passage. The decreases can be attributed to the air coming from an industrial area and the rainout effects of the typhoon, respectively. During the passage of the stationary front, δ 13 C-CO 2 and δ 18 O-CO 2 increased, while δ 2 H-H 2 Ov and δ 18 O-H 2 Ov decreased. These changes can be attributed to the air coming from rural areas and the air surrounding the observational site changing from a subtropical air mass to a subpolar air mass during the passage of the stationary front. A clear relationship was observed between the isotopic CO 2 and water vapour and the meteorological phenomena. Therefore, isotopic information of CO 2 and H 2 Ov could be used as a tracer of meteorological information.

Atmospheric pressure plasma vapour coatings

NARCIS (Netherlands)

Sanden, van de M.C.M.; Starostine, S.; Premkumar, P.A.; Creatore, M.; Vries, de H.W.; Kondruweit, S.; Szyszka, B.; Pütz, J.

2010-01-01

The dielectric barrier discharge (DBD) is recognized as a promising tool of thin films deposition on various substrates at atmospheric pressure. Emerging applications including encapsulation of flexible solar cells and flexible displays require large scale low costs production cif transparent

Vapour trap development and operational experience

International Nuclear Information System (INIS)

Jansing, W.; Kirchner, G.; Menck, J.

1977-01-01

Sodium aerosols have the unpleasant characteristic that they deposit at places with low temperature level. This effect can be utilized when sodium aerosols are to be trapped at places which are determined beforehand. Thus vapour traps were developed which can filter sodium vapour from the cover gas. By this means the necessity was eliminated to heat all gas lines and gas systems with trace heaters just as all sodium lines are heated. It was of special interest for the INTERATOM to develop vapour traps which must not be changed or cleaned after a certain limited operating period. The vapour traps were supposed to enable maintenance free operation, i.e. they were to operate 'self cleaning'

Making ET AAS Determination Less Dependent on Vapourization ...

African Journals Online (AJOL)

NICO

The quantification of the analytes in ET AAS is normally attained by the measurement and integration of transient absorbance. High degree of atomization and constant vapour transportation rate for the analyte atoms in the absorption volume are considered to be crucial to grant correctness of the measurements. However ...

A research of vapour-film characteristics of inverted-annular flow film boiling by visual method

International Nuclear Information System (INIS)

Xu Jijun; Guo Zhichao; Yan An; Bi Haoran

1988-01-01

The vapour-film characteristics are an interesting topic in inverted-annular flow film boiling. A practical set of experimental rig has been designed and constructed for visual observation. Photographic method is adopted for obtaining number of photographs in the conditions of steady state. For references at hands, photographs under steady conditions of water flow film boiling have not been published yet. This paper discusses the typical vapour film characteristics and regards Elias' two-region model summarized from transient visual experiment as reasonable. In addition, under heated conditions, at least, three types of vapour-water interfaces have been observed. They are asymmetric sine waves, symmetic varicose waves, and roll waves offered by Jarlais from an adiabatic simulation. In diabatic conditions a transition of flow pattern to slug flow is usually caused by hydrodynamic instability and/or by thermodynamic instability. The effects of mass velocity, inlet subcooling, heat flux input, initial quality and pressure to vapour-film characteristics are described. An empirical correlation is fitted to 23 sets of tests of discussion

Line pressure effects on differential pressure measurements

International Nuclear Information System (INIS)

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

1982-01-01

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

Near real-time estimation of water vapour in the troposphere using ground GNSS and the meteorological data

Directory of Open Access Journals (Sweden)

J. Bosy

2012-09-01

Full Text Available The near real-time (NRT high resolution water vapour distribution models can be constructed based on GNSS observations delivered from Ground Base Augmentation Systems (GBAS and ground meteorological data. Since 2008 in the territory of Poland, a GBAS system called ASG-EUPOS (Active Geodetic Network has been operating. This paper addresses the problems concerning construction of the NRT model of water vapour distribution in the troposphere near Poland. The first section presents all available GNSS and ground meteorological stations in the area of Poland and neighbouring countries. In this section, data feeding scheme is discussed, together with timeline and time resolution. The high consistency between measured and interpolated temperature value is shown, whereas some discrepancy in the pressure is observed. In the second section, the NRT GNSS data processing strategy of ASG-EUPOS network is discussed. Preliminary results show fine alignment of the obtained Zenith Troposphere Delays (ZTDs with reference data from European Permanent Network (EPN processing center. The validation of NRT troposphere products against daily solution shows 15 mm standard deviation of obtained ZTD differences. The last section presents the first results of 2-D water vapour distribution above the GNSS network and application of the tomographic model to 3-D distribution of water vapour in the atmosphere. The GNSS tomography model, working on the simulated data from numerical forecast model, shows high consistency with the reference data (by means of standard deviation 4 mm km−1 or 4 ppm, however, noise analysis shows high solution sensitivity to errors in observations. The discrepancy for real data preliminary solution (measured as a mean standard deviation between reference NWP data and tomography data was on the level of 9 mm km−1 (or 9 ppm in terms of wet refractivity.

Characterisation and optical vapour sensing properties of PMMA thin films

Energy Technology Data Exchange (ETDEWEB)

Capan, I. [Balikesir University, Science and Arts Faculty, Physics Department, 10100 Balikesir (Turkey)], E-mail: inci.capan@gmail.com; Tarimci, C. [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan, Ankara (Turkey); Hassan, A.K. [Sheffield Hallam University, Materials and Engineering Research Institute, City Campus, Pond Street, Sheffield S1 1WB (United Kingdom); Tanrisever, T. [Balikesir University, Science and Arts Faculty, Chemistry Department, 10100 Balikesir (Turkey)

2009-01-01

The present article reports on the characterisation of spin coated thin films of poly (methyl methacrylate) (PMMA) for their use in organic vapour sensing application. Thin film properties of PMMA are studied by UV-visible spectroscopy, atomic force microscopy and surface plasmon resonance (SPR) technique. Results obtained show that homogeneous thin films with thickness in the range between 6 and 15 nm have been successfully prepared when films were spun at speeds between 1000-5000 rpm. Using SPR technique, the sensing properties of the spun films were studied on exposures to several halohydrocarbons including chloroform, dichloromethane and trichloroethylene. Data from measured kinetic response have been used to evaluate the sensitivity of the studied films to the various analyte molecules in terms of normalised response (%) per unit concentration (ppm). The highest PMMA film sensitivity of 0.067 normalised response per ppm was observed for chloroform vapour, for films spun at 1000 rpm. The high film's sensitivity to chloroform vapour was ascribed mainly to its solubility parameter and molar volume values. Effect of film thickness on the vapour sensing properties is also discussed.

Volatility of components of saturated vapours of UCl4-CsCl and UCl4-LiCl molten mixtures

International Nuclear Information System (INIS)

Smirnov, M.V.; Kudyakov, V.Ya.; Salyulev, A.B.; Komarov, V.E.; Posokhin, Yu.V.; Afonichkin, V.K.

1979-01-01

The flow method has been used for measuring the volatility of the components from UCl 4 -CsCl and UCl 4 -LiCl melted mixtures containing 2.0, 5.0, 12.0, 25.0, 33.0, 50.0, 67.0, and 83.0 mol.% of UCl 4 within the temperature ranges of 903-1188 K and 740-1200 K, respectively. The chemical composition of saturated vapours above the melted salts has been determined. The melted mixtures in question exhibit negative deviation from ideal behaviour. Made was the conclusion about the presence in a vapour phase, along with monomeric UCl 4 , LiCl, CsCl and Li 2 Cl 2 , Cs 2 Cl 2 dimers of double compounds of the MeUCl 5 most probable composition. Their absolute contribution into a total pressure above the UCl 4 -CsCl melted mixtures is considerably smaller than above the UCl 4 -LiCl mixtures

Pressure Measurement Systems

Science.gov (United States)

1990-01-01

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

Evaporation of tungsten in vacuum at low hydrogen and water vapor pressures

International Nuclear Information System (INIS)

Andrievskij, R.A.; Galkin, E.A.; Khromonozhkin, V.V.

1981-01-01

The results of experimental investigations of tungsten evaporation rates in the temperature range 1650-2500 K, partial hydrogen and water vapours pressures 1x10 -5 -10 Pa are presented. Experi-- mental plant, equipment employed and radiometric technique of tungsten evaporation study are described. The dependences of evaporation rate and probabilities of tungsten oxidation by residual vacuum water vapours and dependences of tungsten evaporation rate on partial hydrogen and water vapours pressures are determined [ru

Novel method for water vapour monitoring using wireless communication networks measurements

Science.gov (United States)

David, N.; Alpert, P.; Messer, H.

2010-09-01

We propose a new technique for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from microwave links used in a backhaul cellular network that show very good correlation with surface station humidity measurements (comparisons were performed for several links, found at different locations, during different time periods, showing correlations in the range of 0.5-0.9).

Gravimetric phenotyping of whole plant transpiration responses to atmospheric vapour pressure deficit identifies genotypic variation in water use efficiency.

Science.gov (United States)

Ryan, Annette C; Dodd, Ian C; Rothwell, Shane A; Jones, Ros; Tardieu, Francois; Draye, Xavier; Davies, William J

2016-10-01

There is increasing interest in rapidly identifying genotypes with improved water use efficiency, exemplified by the development of whole plant phenotyping platforms that automatically measure plant growth and water use. Transpirational responses to atmospheric vapour pressure deficit (VPD) and whole plant water use efficiency (WUE, defined as the accumulation of above ground biomass per unit of water used) were measured in 100 maize (Zea mays L.) genotypes. Using a glasshouse based phenotyping platform with naturally varying VPD (1.5-3.8kPa), a 2-fold variation in WUE was identified in well-watered plants. Regression analysis of transpiration versus VPD under these conditions, and subsequent whole plant gas exchange at imposed VPDs (0.8-3.4kPa) showed identical responses in specific genotypes. Genotype response of transpiration versus VPD fell into two categories: 1) a linear increase in transpiration rate with VPD with low (high WUE) or high (low WUE) transpiration rate at all VPDs, 2) a non-linear response with a pronounced change point at low VPD (high WUE) or high VPD (low WUE). In the latter group, high WUE genotypes required a significantly lower VPD before transpiration was restricted, and had a significantly lower rate of transpiration in response to VPD after this point, when compared to low WUE genotypes. Change point values were significantly positively correlated with stomatal sensitivity to VPD. A change point in stomatal response to VPD may explain why some genotypes show contradictory WUE rankings according to whether they are measured under glasshouse or field conditions. Furthermore, this novel use of a high throughput phenotyping platform successfully reproduced the gas exchange responses of individuals measured in whole plant chambers, accelerating the identification of plants with high WUE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Phase diagrams of (vapour + liquid) equilibrium for binary mixtures of α,α,α-trifluorotoluene with ethanol, or benzene, or chloroform at pressure 101.4 kPa

International Nuclear Information System (INIS)

Atik, Zadjia

2008-01-01

(Vapour + liquid) equilibrium (VLE) of binary mixtures of (ethanol + α,α,α-trifluorotoluene), (benzene + α,α,α-trifluorotoluene), and (chloroform + α,α,α-trifluorotoluene) have been investigated at the pressure 101.4 kPa using the dynamic-ebulliometry method over the whole composition range. The correlated VLE phase diagrams were adequately described by means of NRTL and UNIQUAC thermodynamic models. Fair attractive energies in the first two systems are capable to yield azeotropes, while moderate repulsive energies in the later system make it zeotrope

Middle atmospheric water vapour and dynamics in the vicinity of the polar vortex during the Hygrosonde-2 campaign

Directory of Open Access Journals (Sweden)

S. Lossow

2009-07-01

Full Text Available The Hygrosonde-2 campaign took place on 16 December 2001 at Esrange/Sweden (68° N, 21° E with the aim to investigate the small scale distribution of water vapour in the middle atmosphere in the vicinity of the Arctic polar vortex. In situ balloon and rocket-borne measurements of water vapour were performed by means of OH fluorescence hygrometry. The combined measurements yielded a high resolution water vapour profile up to an altitude of 75 km. Using the characteristic of water vapour being a dynamical tracer it was possible to directly relate the water vapour data to the location of the polar vortex edge, which separates air masses of different character inside and outside the polar vortex. The measurements probed extra-vortex air in the altitude range between 45 km and 60 km and vortex air elsewhere. Transitions between vortex and extra-vortex usually coincided with wind shears caused by gravity waves which advect air masses with different water vapour volume mixing ratios.

From the combination of the results from the Hygrosonde-2 campaign and the first flight of the optical hygrometer in 1994 (Hygrosonde-1 a clear picture of the characteristic water vapour distribution inside and outside the polar vortex can be drawn. Systematic differences in the water vapour concentration between the inside and outside of the polar vortex can be observed all the way up into the mesosphere. It is also evident that in situ measurements with high spatial resolution are needed to fully account for the small-scale exchange processes in the polar winter middle atmosphere.

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

NARCIS (Netherlands)

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

2008-01-01

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

GPS water vapour tomography: preliminary results from the ESCOMPTE field experiment

Science.gov (United States)

Champollion, C.; Masson, F.; Bouin, M.-N.; Walpersdorf, A.; Doerflinger, E.; Bock, O.; Van Baelen, J.

2005-03-01

Water vapour plays a major role in atmospheric processes but remains difficult to quantify due to its high variability in time and space and the sparse set of available measurements. The GPS has proved its capacity to measure the integrated water vapour at zenith with the same accuracy as other methods. Recent studies show that it is possible to quantify the integrated water vapour in the line of sight of the GPS satellite. These observations can be used to study the 3D heterogeneity of the troposphere using tomographic techniques. We develop three-dimensional tomographic software to model the three-dimensional distribution of the tropospheric water vapour from GPS data. First, the tomographic software is validated by simulations based on the realistic ESCOMPTE GPS network configuration. Without a priori information, the absolute value of water vapour is less resolved as opposed to relative horizontal variations. During the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers was operated for 2 weeks within a 20×20-km area around Marseille (southern France). The network extends from sea level to the top of the Etoile chain (˜700 m high). Optimal results have been obtained with time windows of 30-min intervals and input data evaluation every 15 min. The optimal grid for the ESCOMTE geometrical configuration has a horizontal step size of 0.05°×0.05° and 500 m vertical step size. Second, we have compared the results of real data inversions with independent observations. Three inversions have been compared to three successive radiosonde launches and shown to be consistent. A good resolution compared to the a priori information is obtained up to heights of 3000 m. A humidity spike at 4000-m altitude remains unresolved. The reason is probably that the signal is spread homogeneously over the whole network and that such a feature is not resolvable by tomographic techniques. The results of our pure GPS inversion show a correlation with

The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour

International Nuclear Information System (INIS)

Scott, T.B.; Petherbridge, J.R.; Harker, N.J.; Ball, R.J.; Heard, P.J.; Glascott, J.; Allen, G.C.

2011-01-01

Highlights: → High resolution imagery (FIB, SEM and SIMS) of carbide inclusions in uranium metal. → Real time images following the reaction of the carbide inclusions with water vapour. → Shown preferential consumption of carbide over that of the bulk metal. → Quantity of impurities in the metal therefore seriously influence reaction rate. → Metal purity must be considered when storing uranium in air or moist conditions. - Abstract: The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO 3 .xH 2 O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets.

The oxidative corrosion of carbide inclusions at the surface of uranium metal during exposure to water vapour.

Science.gov (United States)

Scott, T B; Petherbridge, J R; Harker, N J; Ball, R J; Heard, P J; Glascott, J; Allen, G C

2011-11-15

The reaction between uranium and water vapour has been well investigated, however discrepancies exist between the described kinetic laws, pressure dependence of the reaction rate constant and activation energies. Here this problem is looked at by examining the influence of impurities in the form of carbide inclusions on the reaction. Samples of uranium containing 600 ppm carbon were analysed during and after exposure to water vapour at 19 mbar pressure, in an environmental scanning electron microscope (ESEM) system. After water exposure, samples were analysed using secondary ion mass spectrometry (SIMS), focused ion beam (FIB) imaging and sectioning and transmission electron microscopy (TEM) with X-ray diffraction (micro-XRD). The results of the current study indicate that carbide particles on the surface of uranium readily react with water vapour to form voluminous UO(3) · xH(2)O growths at rates significantly faster than that of the metal. The observation may also have implications for previous experimental studies of uranium-water interactions, where the presence of differing levels of undetected carbide may partly account for the discrepancies observed between datasets. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Measuring variations of δ18O and δ2H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study

Directory of Open Access Journals (Sweden)

S. Pfahl

2012-07-01

Full Text Available Variations of stable water isotopes in water vapour have become measurable at a measurement frequency of about 1 Hz in recent years using novel laser spectroscopic techniques. This enables us to perform continuous measurements for process-based investigations of the atmospheric water cycle at the time scales relevant for synoptic and mesoscale meteorology. An important prerequisite for the interpretation of data from automated field measurements lasting for several weeks or months is a detailed knowledge about instrument properties and the sources of measurement uncertainty. We present here a comprehensive characterisation and comparison study of two commercial laser spectroscopic systems based on cavity ring-down spectroscopy (Picarro and off-axis integrated cavity output spectroscopy (Los Gatos Research. The uncertainty components of the measurements were first assessed in laboratory experiments, focussing on the effects of (i water vapour mixing ratio, (ii measurement stability, (iii uncertainties due to calibration and (iv response times of the isotope measurements due to adsorption-desorption processes on the tubing and measurement cavity walls. Based on the experience from our laboratory experiments, we set up a one-week field campaign for comparing measurements of the ambient isotope signals from the two laser spectroscopic systems. The optimal calibration strategy determined for both instruments was applied as well as the correction functions for water vapour mixing ratio effects. The root mean square difference between the isotope signals from the two instruments during the field deployment was 2.3‰ for δ2H, 0.5‰ for δ18O and 3.1‰ for deuterium excess. These uncertainty estimates from field measurements compare well to those found in the laboratory experiments. The present quality of measurements from laser spectroscopic instruments combined with a calibration system opens new possibilities for investigating the atmospheric

Airborne hygrometer calibration inter-comparison against a metrological water vapour standard

Science.gov (United States)

Smorgon, Denis; Boese, Norbert; Ebert, Volker

2014-05-01

of PTB and a validated, two-pressure generator acting as a highly stable and reproducible source of water vapour. The aim of AV2-B was to perform an absolute, metrological comparison of the field instruments/calibration infrastructures to the metrological humidity scale, and to collect essential information about methods and procedures used by the atmospheric community for instrument calibration and validation, in order to investigate e.g. the necessity and possible comparability advantage by a standardized calibration procedure. The work will give an overview over the concept of the AV2-B inter-comparison, the various general measurement and calibration principles, and discuss the outcome and consequences of the comparison effort. The AQUAVIT effort is linked to the EMRP project METEOMET (ENV07) and partially supported by the EMRP and ENV07. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. [1] H. Saathoff, C. Schiller, V. Ebert, D. W. Fahey, R.-S. Gao, O. Möhler, and the aquavit team, The AQUAVIT formal intercomparison of atmospheric water measurement methods, 5th General Assembly of the European Geosciences Union, 13-18 April 2008, Vienna, Austria Keywords: humidity, water vapour, inter-comparison, airborne instruments.

Thermodynamic study of multi-effect thermal vapour-compression desalination systems

International Nuclear Information System (INIS)

Samaké, Oumar; Galanis, Nicolas; Sorin, Mikhail

2014-01-01

The parametric analysis of a multi-effect-evaporation (MEE) desalination system combined with a thermal-vapour-compression (TVC) process activated by a gaseous stream of specified flowrate and temperature was performed based on the principles of classical (1st and 2nd laws) and finite-size thermodynamics. The MEE subsystem was treated as a black box and therefore the results are valid for any combination of physical characteristics and internal operational conditions of this subsystem. They show the effects of four design variables (the motive fluid pressure and the compression ratio of the ejector, the condenser temperature pinch and the ratio of rejected to supplied seawater) on significant operating quantities and performance indicators such as: energy supplied by the heat source; motive fluid flowrate; flowrates of the supplied seawater and produced potable water; specific heat consumption; thermal conductance of the vapour generator and the condenser; exergy destruction by the MEE, the ejector and the vapour generator. Based on the obtained results recommendations are formulated for the optimal choice of values for the four design variables. - Highlights: • Model of a MEE-TVC desalination system independent of MEE characteristics. • Parametric study based on classical (1st and 2nd law) and finite-size thermodynamics. • Effect of 4 design parameters on operating conditions and performance indicators. • Recommended values for the design parameters

Remote sensing of water vapour profiles in the framework of the Total Carbon Column Observing Network (TCCON

Directory of Open Access Journals (Sweden)

M. Schneider

2010-12-01

Full Text Available We show that the near infrared solar absorption spectra recorded in the framework of the Total Carbon Column Observing Network (TCCON can be used to derive the vertical distribution of tropospheric water vapour. The resolution of the TCCON spectra of 0.02 cm⁻¹ is sufficient for retrieving lower and middle/upper tropospheric water vapour concentrations with a vertical resolution of about 3 and 8 km, respectively. We document the good quality of the remotely-sensed profiles by comparisons with coincident in-situ Vaisala RS92 radiosonde measurements. Due to the high measurement frequency, the TCCON water vapour profile data offer novel opportunities for estimating the water vapour variability at different timescales and altitudes.

[Qualitative Determination of Organic Vapour Using Violet and Visible Spectrum].

Science.gov (United States)

Jiang, Bo; Hu, Wen-zhong; Liu, Chang-jian; Zheng, Wei; Qi, Xiao-hui; Jiang, Ai-li; Wang, Yan-ying

2015-12-01

Vapours of organic matters were determined qualitatively employed with ultraviolet-visible absorption spectroscopy. Vapours of organic matters were detected using ultraviolet-visible spectrophotometer employing polyethylene film as medium, the ultraviolet and visible absorption spectra of vegetable oil vapours of soybean oil, sunflower seed oil, peanut oil, rapeseed oil, sesame oil, cotton seed oil, tung tree seed oil, and organic compound vapours of acetone, ethyl acetate, 95% ethanol, glacial acetic acid were obtained. Experimental results showed that spectra of the vegetable oil vapour and the organic compound vapour could be obtained commendably, since ultra violet and visible spectrum of polyethylene film could be deducted by spectrograph zero setting. Different kinds of vegetable oils could been distinguished commendably in the spectra since the λ(max), λ(min), number of absorption peak, position, inflection point in the ultra violet and visible spectra obtained from the vapours of the vegetable oils were all inconsistent, and the vapours of organic compounds were also determined perfectly. The method had a good reproducibility, the ultraviolet and visible absorption spectra of the vapours of sunflower seed oil in 10 times determination were absolutely the same. The experimental result indicated that polyethylene film as a kind of medium could be used for qualitative analysis of ultraviolet and visible absorption spectroscopy. The method for determination of the vapours of the vegetable oils and organic compounds had the peculiarities of fast speed analysis, well reproducibility, accuracy and reliability and low cost, and so on. Ultraviolet and visible absorption spectrum of organic vapour could provide feature information of material vapour and structural information of organic compound, and provide a novel test method for identifying vapour of compound and organic matter.

Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

KAUST Repository

Vakarelski, Ivan Uriev

2012-09-12

In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

Stabilization of Leidenfrost vapour layer by textured superhydrophobic surfaces

KAUST Repository

Vakarelski, Ivan Uriev; Patankar, Neelesh A.; Marston, Jeremy; Chan, Derek Y C; Thoroddsen, Sigurdur T

2012-01-01

In 1756, Leidenfrost observed that water drops skittered on a sufficiently hot skillet, owing to levitation by an evaporative vapour film. Such films are stable only when the hot surface is above a critical temperature, and are a central phenomenon in boiling. In this so-called Leidenfrost regime, the low thermal conductivity of the vapour layer inhibits heat transfer between the hot surface and the liquid. When the temperature of the cooling surface drops below the critical temperature, the vapour film collapses and the system enters a nucleate-boiling regime, which can result in vapour explosions that are particularly detrimental in certain contexts, such as in nuclear power plants. The presence of these vapour films can also reduce liquid-solid drag. Here we show how vapour film collapse can be completely suppressed at textured superhydrophobic surfaces. At a smooth hydrophobic surface, the vapour film still collapses on cooling, albeit at a reduced critical temperature, and the system switches explosively to nucleate boiling. In contrast, at textured, superhydrophobic surfaces, the vapour layer gradually relaxes until the surface is completely cooled, without exhibiting a nucleate-boiling phase. This result demonstrates that topological texture on superhydrophobic materials is critical in stabilizing the vapour layer and thus in controlling-by heat transfer-the liquid-gas phase transition at hot surfaces. This concept can potentially be applied to control other phase transitions, such as ice or frost formation, and to the design of low-drag surfaces at which the vapour phase is stabilized in the grooves of textures without heating. © 2012 Macmillan Publishers Limited. All rights reserved.

Collective dynamics in dense Hg vapour

International Nuclear Information System (INIS)

Ishikawa, D; Inui, M; Matsuda, K; Tamura, K; Baron, A Q R; Tsutsui, S; Tanaka, Y; Ishikawa, T

2004-01-01

The dynamic structure factor, S(Q,ο), of dense Hg vapour has been measured by high resolution inelastic x-ray scattering for densities of 3.0, 2.1 and 1.0 g cm -3 corresponding to 0.52, 0.36 and 0.17 times the critical density, respectively, and for momentum transfers between 2.0 and 48 nm -1 . Analysis of the longitudinal current-current correlation function in the framework of generalized hydrodynamics reveals that the frequencies of the collective excitations increase faster with Q than estimated from the macroscopic speed of sound. The ratios of the frequencies were found to be 1.27 at 3.0 g cm -3 , 1.12 at 2.1 g cm -3 and 1.10 at 1.0 g cm -3 . The sound velocity obtained from the present experiments is well reproduced by a wavenumber dependent adiabatic sound velocity, which means that the collective modes remain in the spectra of dense Hg vapour. (letter to the editor)

First Townsend coefficient of organic vapour in avalanche counters

International Nuclear Information System (INIS)

Sernicki, J.

1990-01-01

A new concept is presented in the paper for implementing the proven method of determining the first Townsend coefficient (α) of gases using an avalanche counter. The A and B gas constants, interrelated by the expression α/p=A exp[-B/(K/p)], are analyzed. Parallel-plate avalanche counters (PPAC) with an electrode spacing d from 0.1 to 0.4 cm have been employed for the investigation, arranged to register low-energy alpha particles at n-heptane vapour pressures of p≥5 Torr. An in-depth discussion is given, covering the veracity and the behaviour vs K/p, of the n-heptane A and B constants determined at reduced electric-field intensity values ranging from 173.5 to 940 V/cm Torr; the constants have been found to depend upon d. The results of the investigation are compared to available data of the α coefficient of organic vapours used in avalanche counters. The PPAC method of determining α reveals some imperfections at very low values of the pd product. (orig.)

Heat transfer and pressure drop of condensation of hydrocarbons in tubes

Science.gov (United States)

Fries, Simon; Skusa, Severin; Luke, Andrea

2018-03-01

The heat transfer coefficient and pressure drop are investigated for propane. Two different mild steel plain tubes and saturation pressures are considered for varying mass flux and vapour quality. The pressure drop is compared to the Friedel-Correlation with two different approaches to determine the friction factor. The first is calculation as proposed by Friedel and the second is through single phase pressure drop investigations. For lower vapour qualities the experimental results are in better agreement with the approach of the calculated friction factor. For higher vapour qualities the experimental friction factor is more precise. The pressure drop increases for a decreasing tube diameter and saturation pressure. The circumferential temperature profile and heat transfer coefficients are shown for a constant vapour quality at varying mass fluxes. The subcooling is highest for the bottom of the tube and lowest for the top. The average subcooling as well as the circumferential deviation decreases for rising mass fluxes. The averaged heat transfer coefficients are compared to the model proposed by Thome and Cavallini. The experimental results are in good agreement with both correlations, however the trend is better described with the correlation from Thome. The experimental heat transfer coefficients are under predicted by Thome and over predicted by Cavallini.

Influence of leaf-to-air vapour pressure deficit (VPD) on the biochemistry and physiology of photosynthesis in Prosopis juliflora.

Science.gov (United States)

Shirke, Pramod A; Pathre, Uday V

2004-09-01

The effect of leaf-to-air vapour pressure deficit (VPD) was studied in well-watered, potted, 1-2-year-old plants of the leguminous tree P. juliflora grown outside in northern India. The long-term responses to VPD were analysed from diurnal and seasonal variations in gas exchange parameters measured in two cohorts of leaves produced in February and July, respectively. In general, inhibitory effects of high VPD were visible only when the VPD level exceeded a threshold of >3 kPa. There was a substantial decline in net photosynthesis rate and stomatal conductance at high VPD >4 kPa and transpiration showed a decrease in steady-state rate or feedforward response to VPD. The feedforward responses were visible in all seasons, although the plants were exposed to a wide range of VPD during the year and leaf relative water content was constant. The maximum quantum efficiency of PSII measured predawn was constant (around 0.8) in all seasons except summer. Short-term experiments showed that, although gas exchange was severely affected by high VPD in the leaves of both cohorts, the plant maintained a constant, water use efficiency in different seasons. High VPD also caused reductions in Rubisco activity, affecting carboxylation efficiency, and reductions in sucrose and starch content due to a decrease in the activity of sucrose-phosphate synthase. However, the relative quantum yield of PSII and electron transport rates measured at 1500 micromol m(-2) s(-1) were unaffected by increasing VPD, indicating the presence of a large alternative sink possibly, photorespiration. The overall results showed that P. juliflora can withstand high VPD by reducing metabolic activity and by effective adjustments in the partitioning of electron flow between assimilation and non-assimilation processes, which, in turn, imposed a strong limitation on the potential carbon gain.

Thermogravimetric analysis and dissociation pressure of caesium trihalides

International Nuclear Information System (INIS)

Harris, G.S.; McKechnie, J.S.

1982-01-01

We have carried out a thermogravimetric study of caesium trihalides to obtain, from the procedural decomposition temperatures, an order of apparent thermal stability which could be compared with the order of thermodynamic stability obtained from vapour pressure measurements. Thermogravimetric analysis could also prove to be a useful method for rapid analysis of metal polyhalides. The thermograms indicated a one-step decomposition for each compound; the procedural decomposition temperatures and percentage weight losses obtained are given. Dissociation pressures were measured and values of equilibrium constant and enthalpy of dissociation were calculated. The results are given. The 'stability' order obtained is discussed. (U.K.)

A rate equation model of stomatal responses to vapour pressure deficit and drought

Directory of Open Access Journals (Sweden)

Shanahan ST

2002-08-01

Full Text Available Abstract Background Stomata respond to vapour pressure deficit (D – when D increases, stomata begin to close. Closure is the result of a decline in guard cell turgor, but the link between D and turgor is poorly understood. We describe a model for stomatal responses to increasing D based upon cellular water relations. The model also incorporates impacts of increasing levels of water stress upon stomatal responses to increasing D. Results The model successfully mimics the three phases of stomatal responses to D and also reproduces the impact of increasing plant water deficit upon stomatal responses to increasing D. As water stress developed, stomata regulated transpiration at ever decreasing values of D. Thus, stomatal sensitivity to D increased with increasing water stress. Predictions from the model concerning the impact of changes in cuticular transpiration upon stomatal responses to increasing D are shown to conform to experimental data. Sensitivity analyses of stomatal responses to various parameters of the model show that leaf thickness, the fraction of leaf volume that is air-space, and the fraction of mesophyll cell wall in contact with air have little impact upon behaviour of the model. In contrast, changes in cuticular conductance and membrane hydraulic conductivity have significant impacts upon model behaviour. Conclusion Cuticular transpiration is an important feature of stomatal responses to D and is the cause of the 3 phase response to D. Feed-forward behaviour of stomata does not explain stomatal responses to D as feedback, involving water loss from guard cells, can explain these responses.

Modelling and interpreting the isotopic composition of water vapour in convective updrafts

Directory of Open Access Journals (Sweden)

M. Bolot

2013-08-01

Full Text Available The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed-phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters, including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener–Bergeron–Findeisen process. As all of these processes are related to updraft strength, particle size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

Modelling and interpreting the isotopic composition of water vapour in convective updrafts

Science.gov (United States)

Bolot, M.; Legras, B.; Moyer, E. J.

2013-08-01

The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed-phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters, including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener-Bergeron-Findeisen process). As all of these processes are related to updraft strength, particle size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

Modelling and intepreting the isotopic composition of water vapour in convective updrafts

Science.gov (United States)

Bolot, M.; Legras, B.; Moyer, E. J.

2012-08-01

The isotopic compositions of water vapour and its condensates have long been used as tracers of the global hydrological cycle, but may also be useful for understanding processes within individual convective clouds. We review here the representation of processes that alter water isotopic compositions during processing of air in convective updrafts and present a unified model for water vapour isotopic evolution within undiluted deep convective cores, with a special focus on the out-of-equilibrium conditions of mixed phase zones where metastable liquid water and ice coexist. We use our model to show that a combination of water isotopologue measurements can constrain critical convective parameters including degree of supersaturation, supercooled water content and glaciation temperature. Important isotopic processes in updrafts include kinetic effects that are a consequence of diffusive growth or decay of cloud particles within a supersaturated or subsaturated environment; isotopic re-equilibration between vapour and supercooled droplets, which buffers isotopic distillation; and differing mechanisms of glaciation (droplet freezing vs. the Wegener-Bergeron-Findeisen process). As all of these processes are related to updraft strength, droplet size distribution and the retention of supercooled water, isotopic measurements can serve as a probe of in-cloud conditions of importance to convective processes. We study the sensitivity of the profile of water vapour isotopic composition to differing model assumptions and show how measurements of isotopic composition at cloud base and cloud top alone may be sufficient to retrieve key cloud parameters.

Vapour and air bubble collapse analysis in viscous compressible water

Directory of Open Access Journals (Sweden)

Gil Bazanini

2001-01-01

Full Text Available Numerical simulations of the collapse of bubbles (or cavities are shown, using the finite difference method, taking into account the compressibility of the liquid, expected to occur in the final stages of the collapse process. Results are compared with experimental and theoretical data for incompressible liquids, to see the influence of the compressibility of the water in the bubble collapse. Pressure fields values are calculated in an area of 800 x 800 mm, for the case of one bubble under the hypothesis of spherical symmetry. Results are shown as radius versus time curves for the collapse (to compare collapse times, and pressure curves in the plane, for pressure fields. Such calculations are new because of their general point of view, since the existing works do not take into account the existence of vapour in the bubble, neither show the pressure fields seen here. It is also expected to see the influence of the compressibility of the water in the collapse time, and in the pressure field, when comparing pressure values.

The investigation on the vapour liquid phase equilibrium of (ammonia + 1,1,1,2-tetrafluoroethane) system over the temperatures ranging from (243.150 to 283.150) K

International Nuclear Information System (INIS)

Zhao, Yanxing; Dong, Xueqiang; Zhong, Quan; Gong, Maoqiong; Shen, Jun

2017-01-01

Highlights: • The vapour liquid equilibrium for ammonia + 1,1,1,2-tetrafluoroethane system was studied. • Measurements were based on vapour phase single recirculation method. • A positive azeotropic behaviour was exhibited at the experimental temperature range. - Abstract: To blend ammonia with some hydrofluorocarbons may give these mixed refrigerants lower flammability and global warming potential. In this paper, the isothermal vapour liquid equilibrium (VLE) of (ammonia + 1,1,1,2-tetrafluoroethane) system at temperatures ranging from (243.150 to 283.150) K are presented. Two models were employed to regress the experimental VLE results, namely the Peng–Robinson (PR) equation of state with the simple van der waals (VDW) mixing rule; the Peng–Robinson equation of state combined non-random two-liquid (NRTL) activity coefficient model with the modified Huron-Vidal one-order (MHV1) mixing rule. The maximum average absolute relative deviation of pressure (AARDp) and average absolute deviation of the vapour phase mole fraction (AADy) for PR-VDW are 0.56% and 0.010, respectively, while the maximum AARDp and AADy for PR-MHV1-NRTL are 0.27% and 0.014, respectively. Positive azeotropic behaviour was exhibited at each temperature investigated.

Assessment, measurement and correlation of (vapour + liquid) equilibrium of (carbon dioxide + butyl, isobutyl, and amyl formate) systems

International Nuclear Information System (INIS)

Shen, Yanshu; Zheng, Danxing; Li, Xinru; Li, Yun

2013-01-01

Highlights: • Selected three formates that have relative perfect absorption performance for CO 2 . • Measured the VLE data of CO 2 + butyl, isobutyl, and amyl formates systems. • Correlated the VLE data by using PR EOS with two mixing rules and SRK EOS with one mixing rule. • Concluded amyl formate has potential research value as CO 2 physical absorbent. -- Abstract: In this work, three formates (butyl, isobutyl, and amyl formate) were considered as relative perfect CO 2 absorption performance based on the excess Gibbs function as the thermodynamics criterion. An online static-analytical method was used to measure the (vapour + liquid) equilibrium (VLE) data for the CO 2 + butyl, isobutyl, and amyl formates under the pressure of (0.2 to 6) MPa and the temperatures at a range from (283.15 to 343.15) K. Then the VLE data were correlated by Peng–Robinson (PR) equation of state (EOS) with classic mixing rule, PR EOS with Wong–Sandler (WS) mixing rule and Soave–Redlich–Kwong (SRK) EOS with classic mixing rule. It is shown that SRK EOS is comparatively appropriate for CO 2 + butyl formate binary system. Both PR EOS with classic mixing rule and SRK EOS can be used to correlate the binary systems of CO 2 + isobutyl, amyl formate. It is found that the solubility order of three formates for CO 2 from high to low is arranged as CO 2 + amyl formate > CO 2 + butyl formate > CO 2 + isobutyl formate, showing the system of CO 2 + amyl formate has the best absorption performance. By comparison, it indicates that formates have a greater solubility for CO 2 than acetates on the condition of the same temperature and pressure. In addition, the thermophysical properties, mole absorption and mass absorptive amount of several industrial absorbents were assessed and the absorption performance of amyl formate for CO 2 is better than other physical absorbents. Thus, the study concluded that amyl formate has potential research value as physical absorbent for CO 2 capture

A dilute Cu(Ni) alloy for synthesis of large-area Bernal stacked bilayer graphene using atmospheric pressure chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Madito, M. J.; Bello, A.; Dangbegnon, J. K.; Momodu, D. Y.; Masikhwa, T. M.; Barzegar, F.; Manyala, N., E-mail: ncholu.manyala@up.ac.za [Department of Physics, Institute of Applied Materials, SARCHI Chair in Carbon Technology and Materials, University of Pretoria, Pretoria 0028 (South Africa); Oliphant, C. J.; Jordaan, W. A. [National Metrology Institute of South Africa, Private Bag X34, Lynwood Ridge, Pretoria 0040 (South Africa); Fabiane, M. [Department of Physics, Institute of Applied Materials, SARCHI Chair in Carbon Technology and Materials, University of Pretoria, Pretoria 0028 (South Africa); Department of Physics, National University of Lesotho, P.O. Roma 180 (Lesotho)

2016-01-07

A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni homogeneous distribution in Cu foil were confirmed with inductively coupled plasma optical emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface concentration distribution through segregation kinetics. The increase in Ni surface concentration in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene, the number of graphene layers, and the layers stacking order in synthesized bilayer graphene films were confirmed by Raman and electron diffraction measurements. A four point probe station was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer graphene film by increasing Ni content in Cu surface layer.

The exchange reaction between deuterium and water vapour on platinum deposited over a hydrophobic support

International Nuclear Information System (INIS)

Itsuo, Iida; Junko, Kato; Kenzi, Tamuru

1977-01-01

Isotope exchange reaction between deuterium gas and water vapour at room temperature and below on platinum deposited on hydrophobic supports such as polytetrafluoroethylene (PTFE) or Porapak Q (copolymer of styrene and divinylbenzene) was studied and the results were compared with those of the exchange reaction on platinum over hydrophilic support such as alumina. It was demonstrated that the exchange reaction at temperatures below the boiling point of water is markedly retarded by the multilayer adsorption of water over the platinum catalyst deposited on hydrophilic support, whereas the platinum catalyst on hydrophobic support exhibited a high catalytic activity, being not retarded by the water, forming no multilayer of adsorbed water over platinum surface. Therefore in the case of the hydrogen isotope exchange reaction on platinum over hydrophobic support, the chemical exchange rate can be measured even under a saturated vapour pressure of water. The surface area of platinum was estimated by hydrogen chemisorption and hydrogen titration and specific activities of the catalyst were calculated at both room temperature and freezing point of water, which revealed that the specific rate of this reaction does not differ so much over various supports. (orig.) [de

Interactions of fission product vapours with aerosols

Energy Technology Data Exchange (ETDEWEB)

Benson, C G; Newland, M S [AEA Technology, Winfrith (United Kingdom)

1996-12-01

Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350{sup o}C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs.

Interactions of fission product vapours with aerosols

International Nuclear Information System (INIS)

Benson, C.G.; Newland, M.S.

1996-01-01

Reactions between structural and reactor materials aerosols and fission product vapours released during a severe accident in a light water reactor (LWR) will influence the magnitude of the radiological source term ultimately released to the environment. The interaction of cadmium aerosol with iodine vapour at different temperatures has been examined in a programme of experiments designed to characterise the kinetics of the system. Laser induced fluorescence (LIF) is a technique that is particularly amenable to the study of systems involving elemental iodine because of the high intensity of the fluorescence lines. Therefore this technique was used in the experiments to measure the decrease in the concentration of iodine vapour as the reaction with cadmium proceeded. Experiments were conducted over the range of temperatures (20-350 o C), using calibrated iodine vapour and cadmium aerosol generators that gave well-quantified sources. The LIF results provided information on the kinetics of the process, whilst examination of filter samples gave data on the composition and morphology of the aerosol particles that were formed. The results showed that the reaction of cadmium with iodine was relatively fast, giving reaction half-lives of approximately 0.3 s. This suggests that the assumption used by primary circuit codes such as VICTORIA that reaction rates are mass-transfer limited, is justified for the cadmium-iodine reaction. The reaction was first order with respect to both cadmium and iodine, and was assigned as pseudo second order overall. However, there appeared to be a dependence of aerosol surface area on the overall rate constant, making the precise order of the reaction difficult to assign. The relatively high volatility of the cadmium iodide formed in the reaction played an important role in determining the composition of the particles. (author) 23 figs., 7 tabs., 22 refs

Measurements of (p, ρ, T) properties for isobutane in the temperature range from 280 K to 440 K at pressures up to 200 MPa

International Nuclear Information System (INIS)

Miyamoto, H.; Uematsu, M.

2006-01-01

Measurements of (p, ρ, T) properties for isobutane in the compressed liquid phase have been obtained by means of a metal-bellows variable volumometer in the temperature range from 280 K to 440 K at pressures up to 200 MPa. The volume-fraction purity of isobutane used was 0.9999. The expanded uncertainties (k = 2) of temperature, pressure, and density measurements have been estimated to be less than 3 mK, 1.5 kPa (p ≤ 7 MPa), 0.06% (7 MPa 150 MPa), and 0.11%, respectively. In region more than 100 MPa at 280 K and 440 K, the uncertainty in density measurements rise up to 0.15% and 0.23%, respectively. The differences of the present density values at the same temperature between two series of measurements, in which the sample fillings are different, are within the maximum deviation of 0.09% in density, which is enough lower than the expanded uncertainty in density. Eight (p, ρ, T) measurements at the same temperatures and pressures as the literature values have been conducted for comparison. In addition, vapour pressures were measured at T = (280, 300) K. Moreover, the comparisons of the available equations of state with the present measurements are reported

Rewetting of semi-dried ink patterns by vapour annealing for developing a reflow process in reverse offset printing

International Nuclear Information System (INIS)

Kusaka, Yasuyuki; Ushijima, Hirobumi; Sugihara, Kazuyoshi; Koutake, Masayoshi

2017-01-01

A process for reflowing patterned materials for reverse offset printing was developed, with the aim of mitigating the step-coverage problem in multilayered devices. The proposed reflow process involves a single step of vapour annealing at moderate temperatures ranging from 60 to 70 °C. This step successfully changes the height profile of semi-dried ink patterns formed on a silicone blanket, from an initially rectangular shape to a rounded shape. A systematic investigation on the effects of various vapour species and vapour temperatures on the reflow process revealed that the miscibility between the vapour and the ink, and a low boiling point of the respective solvent (high vapour pressure) are the prerequisites for successful reflows of semi-dried ink layers patterned on a silicone blanket. The results suggested that the rewetting of previously semi-dried patterns is the main mechanism in the reflow process, which led to a change in the height profile. Furthermore, the reflowed patterns demonstrated almost identical peak-height thicknesses, irrespective of the width of the patterns. This is a unique property that is unattainable by other printing methods, including gravure offset printing and microcontact printing, wherein printed patterns have rounded shapes without a reflow process, but their thickness inevitably depends on the pattern sizes. (technical note)

Atomic origins of water-vapour-promoted alloy oxidation.

Science.gov (United States)

Luo, Langli; Su, Mao; Yan, Pengfei; Zou, Lianfeng; Schreiber, Daniel K; Baer, Donald R; Zhu, Zihua; Zhou, Guangwen; Wang, Yanting; Bruemmer, Stephen M; Xu, Zhijie; Wang, Chongmin

2018-05-07

The presence of water vapour, intentional or unavoidable, is crucial to many materials applications, such as in steam generators, turbine engines, fuel cells, catalysts and corrosion 1-4 . Phenomenologically, water vapour has been noted to accelerate oxidation of metals and alloys 5,6 . However, the atomistic mechanisms behind such oxidation remain elusive. Through direct in situ atomic-scale transmission electron microscopy observations and density functional theory calculations, we reveal that water-vapour-enhanced oxidation of a nickel-chromium alloy is associated with proton-dissolution-promoted formation, migration, and clustering of both cation and anion vacancies. Protons derived from water dissociation can occupy interstitial positions in the oxide lattice, consequently lowering vacancy formation energy and decreasing the diffusion barrier of both cations and anions, which leads to enhanced oxidation in moist environments at elevated temperatures. This work provides insights into water-vapour-enhanced alloy oxidation and has significant implications in other material and chemical processes involving water vapour, such as corrosion, heterogeneous catalysis and ionic conduction.

Measuring fluid pressure

International Nuclear Information System (INIS)

Lee, A.S.

1978-01-01

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

Volatility of components of saturated vapours of UCl/sub 4/-CsCl and UCl/sub 4/-LiCl molten mixtures

Energy Technology Data Exchange (ETDEWEB)

Smirnov, M V; Kudyakov, V Ya; Salyulev, A B; Komarov, V E; Posokhin, Yu V; Afonichkin, V K

1979-01-01

The flow method has been used for measuring the volatility of the components from UCl/sub 4/-CsCl and UCl/sub 4/-LiCl melted mixtures containing 2.0, 5.0, 12.0, 25.0, 33.0, 50.0, 67.0, and 83.0 mol.% of UCl/sub 4/ within the temperature ranges of 903-1188 K and 740-1200 K, respectively. The chemical composition of saturated vapours above the melted salts has been determined. The melted mixtures in question exhibit negative deviation from ideal behaviour. Made was the conclusion about the presence in a vapour phase, along with monomeric UCl/sub 4/, LiCl, CsCl and Li/sub 2/Cl/sub 2/, Cs/sub 2/Cl/sub 2/ dimers of double compounds of the MeUCl/sub 5/ most probable composition. Their absolute contribution into a total pressure above the UCl/sub 4/-CsCl melted mixtures is considerably smaller than above the UCl/sub 4/ -LiCl mixtures.

Water vapour and carbon dioxide decrease nitric oxide readings

NARCIS (Netherlands)

vanderMark, TW; Kort, E; Meijer, RJ; Postma, DS; Koeter, GH

Measurement of nitric oxide levels in exhaled ah-is commonly performed using a chemiluminescence detector. However, water vapour and carbon dioxide affect the chemiluminescence process, The influence of these gases at the concentrations present in exhaled air has not vet been studied. For this in

Response of water vapour D-excess to land-atmosphere interactions in a semi-arid environment

KAUST Repository

Parkes, Stephen

2016-06-30

The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (dv). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (dET) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime dv values. The low dET observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime dv and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime dv variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of dv values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate dET can generally be expected to show

Heat transfer in vapour-liquid flow of carbon dioxide

International Nuclear Information System (INIS)

Yagov, V.V.

2009-01-01

During the last decade a number of studies of boiling heat transfer in carbon dioxide notably increase. As a field of CO 2 practical using corresponds to high reduced pressures, and a majority of available experimental data on CO 2 flow boiling even in submillimetric channels relate to turbulent liquid flow regimes, a possibility arises to develop sufficiently general method for HTC predicting. Under the above conditions nucleate boiling occurs up to rather high flow quality, even in annular flow regime due to extremely small size of an equilibrium vapour bubble. This conclusion is in agreement with the available experimental data. The predicting equation for nucleate boiling heat transfer developed by the present author in 1988 is valid for any nonmetallic liquid. A contribution of forced convection in heat transfer is calculated according to the Petukhov et al. equation with correction factor, which accounted for an effect of velocity increase due to evaporation. This effect can be essential at relatively small heat fluxes and rather high mass flow rates. The Reynolds analogy and homogeneous model are used in order to account for the convective heat transfer augmentation in two-phase flow. Due to low ratio of liquid and vapour densities at high reduced pressures the homogeneous approximation of two-phase flow seems to be warranted. A total heat transfer coefficient is calculated as an interpolated value of boiling and convective HTCs. The experimental data on CO 2 flow boiling related to regimes before heated wall dryout incipience are in rather good agreement with the calculations. (author)

Autonomous Chemical Vapour Detection by Micro UAV

Directory of Open Access Journals (Sweden)

Kent Rosser

2015-12-01

Full Text Available The ability to remotely detect and map chemical vapour clouds in open air environments is a topic of significant interest to both defence and civilian communities. In this study, we integrate a prototype miniature colorimetric chemical sensor developed for methyl salicylate (MeS, as a model chemical vapour, into a micro unmanned aerial vehicle (UAV, and perform flights through a raised MeS vapour cloud. Our results show that that the system is capable of detecting MeS vapours at low ppm concentration in real-time flight and rapidly sending this information to users by on-board telemetry. Further, the results also indicate that the sensor is capable of distinguishing “clean” air from “dirty”, multiple times per flight, allowing us to look towards autonomous cloud mapping and source localization applications. Further development will focus on a broader range of integrated sensors, increased autonomy of detection and improved engineering of the system.

A simple passive method of collecting water vapour for environmental tritium monitoring

International Nuclear Information System (INIS)

Iida, T.; Fukuda, H.; Ikebe, Y.; Yokoyama, S.

1995-01-01

To investigate the average behaviour of tritium in an atmospheric environment, it is necessary to collect water vapour in air over a long period at numerous locations. For the purpose of the study, the passive method was developed: this is handy, low-priced and could collect water vapour in air without motive power. This paper describes the characteristics of the passive collecting method, the performance of water collection in outdoor air and the measurements of tritium concentrations in water samples collected by the passive method. (author)

Characterization of sorption properties of selected soils from Lublin region by using water vapour adsorption method

Science.gov (United States)

Skic, Kamil; Boguta, Patrycja; Sokołowska, Zofia

2016-04-01

*The studies were carried out within the framework of a research project. The project was financed from funds of National Science Center on the base of decision number DEC-2013/11/D/NZ9/02545 Among many methods proposed to study sorption properties of soils an analysis of adsorption/ desorption isotherm is probably the easiest and most convenient one. It characterizes both quantity and quality of mineral and organic components and also their physical and physicochemical properties. The main aim of this study is comparison of sorption properties of selected Polish soils by using water vapour adsorption method. Samples were taken from the depth of 0-20 cm, from the Lublin region, eastern Poland. Soils were selected on the basis of their different physicochemical properties and were classified as: Haplic Fluvisol, Haplic Chernozem, Mollic Gleysol, Rendzic Phaeozem, Stagnic Luvisol, Haplic Cambisol (WG WRB 2006). Data taken from experimental adsorption isotherms were used to determine parameters of monolayer capacity, specific surface area and the total amount of vapour adsorbed at relative pressure of 0.974. Obtained adsorption and desorption isotherms reviled that adsorbate molecules interacted with the soil particles in different extent. Similar monolayer capacity was observed for Haplic Fluvisol, Haplic Chernozem and Stagnic Luvisol, while for Mollic Gleysol was more than 4 times higher. Mollic Gleysol was also characterized by highest values of specific surface area as well as quantity of adsorbed vapour at relative pressure of 0.974. Higher sorption was caused by presence of soil colloids which contains functional groups of a polar nature (mainly hydroxyls, phenolic and carboxyls). These groups similarly to silicates, oxides, hydratable cations as well as electric charge form adsorption centres for water vapour molecules.

Detection of the contamination of air by tritiated water vapour around the reactor EL3

International Nuclear Information System (INIS)

Lebouleux, P.; Ardellier, A.; Valero, S.

1968-01-01

The authors describe the apparatus used for the detection of the tritiated water vapour contamination in the air around the reactor EL 3. The apparatus consists of two air-circulation ionisation chambers; the air in one of these is dried by passage through a silica-gel column. By carrying out a differential measurement of the ionization currents, it is possible to measure the tritiated water vapour concentration. A theoretical study of the response of the chambers is carried out for two types of emission of the tritiated water vapour: continuous, or in bursts. The experimental work comprises: calibration in the measurement range employed; study of the selectivity for other active gases; study of typical accidents; the interpretation of the results in the case of discontinuous emission, taking into account the desorption from the walls of the measurement chamber, a phenomenon which is observed during the emptying process. The authors give finally actual examples of how to use the results. The apparatus built makes it possible to detect, in less than ten minutes, contamination by tritiated water vapour in the presence of other active gases, in a measurement range of between 3 and 2200 MPC, and with an accuracy of about 25 per cent. A transposition to calculations of the risk to workers should be made with the utmost caution; an envelope of this risk can be drawn up more or less accurately depending on particular cases. (authors) [fr

Capacitive-discharge-pumped copper bromide vapour laser

International Nuclear Information System (INIS)

Sukhanov, V B; Fedorov, V F; Troitskii, V O; Gubarev, F A; Evtushenko, Gennadii S

2007-01-01

A copper bromide vapour laser pumped by a high-frequency capacitive discharge is developed. It is shown that, by using of a capacitive discharge, it is possible to built a sealed off metal halide vapour laser of a simple design allowing the addition of active impurities into the working medium. (letters)

Carbon dioxide and water vapour characteristics on the west coast ...

Indian Academy of Sciences (India)

Carbon dioxide, water vapour, air temperature and wind measurements at 10 Hz sampling rate were carried out over the ... seasonal and annual variations in the CO2 bal- ance. Hence, it is .... motion below produced by shear stress near the.

Annealing of polycrystalline thin film silicon solar cells in water vapour at sub-atmospheric pressures

Czech Academy of Sciences Publication Activity Database

Pikna, Peter; Píč, Vlastimil; Benda, V.; Fejfar, Antonín

2014-01-01

Roč. 54, č. 5 (2014), s. 341-347 ISSN 1210-2709 R&D Projects: GA MŠk 7E10061 EU Projects: European Commission(XE) 240826 - PolySiMode Grant - others:AVČR(CZ) M100101216 Institutional support: RVO:68378271 Keywords : passivation * water vapour * thin film solar cell * polycrystalline silicon (poly-Si) * multicrys- talline silicon (m-Si) * Suns-VOC Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use

Isothermal VapourůLiquid Equilibria and Excess Molar Volumes in the Binary Ethanol + Methyl Propanoate or Methyl Butanoate Systems

Czech Academy of Sciences Publication Activity Database

Constantinescu, D.; Wichterle, Ivan

2002-01-01

Roč. 203, 1-2 (2002), s. 71-82 ISSN 0378-3812 R&D Projects: GA AV ČR IAA4072102 Keywords : vapour pressure * azeotropy * experiment Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.011, year: 2002

Explosives vapour identification in ion mobility spectrometry using a tunable laser ionization source: a comparison with conventional 63Ni ionization

International Nuclear Information System (INIS)

Clark, A.; Deas, R.M.; Kosmidis, C.; Ledingham, K.W.D.; Marshall, A.; Singhal, R.P.

1995-01-01

Laser multiphoton ionization (MPI) is used to produce ions from explosive vapours at atmospheric pressure in air for analysis by ion mobility spectrometry (IMS). In the positive ion mode of detection, NO + ions, generated directly by multiphoton dissociation/ionization of the explosive compounds, show strong variation with laser wavelength. This provides a means of identifying the presence of nitro-containing compounds. Moreover, electrons formed in the MPI of gaseous components in the air carrier stream, primarily O 2 , are transferred via neutral molecular oxygen (O 2 ) to trace explosive vapour, forming negative ions which give rise to characteristic and identifiable ion mobility spectra. Further, negative ion mobility spectra of several explosive vapours are presented using conventional 63 Ni ionization and are compared qualitatively with the laser ionization approach. (author)

Optical and electrical properties of ZrSe3 single crystals grown by chemical vapour transport technique

International Nuclear Information System (INIS)

Patel, Kaushik; Prajapati, Jagdish; Vaidya, Rajiv; Patel, S.G.

2005-01-01

Single crystals of the lamellar compound, ZrSe 3 , were grown by chemical vapour transport technique using iodine as a transporting agent. The grown crystals were characterized with the help of energy dispersive analysis by X-ray (EDAX), which gave confirmation about the stoichiometry. The optical band gap measurement of as grown crystals was carried out with the help of optical absorption spectra in the range 700-1450 nm. The indirect as well as direct band gap of ZrSe 3 were found to be 1.1 eV and 1.47 eV, respectively. The resistivity of the as grown crystals was measured using van der Pauw method. The Hall parameters of the grown crystals were determined at room temperature from Hall effect measurements. Electrical resistivity measurements were performed on this crystal in the temperature range 303-423 K. The crystals were found to exhibit semiconducting nature in this range. The activation energy and anisotropy measurements were carried out for this crystal. Pressure dependence of electrical resistance was studied using Bridgman opposed anvils set up up to 8 GPa. The semiconducting nature of ZrSe 3 single crystal was inferred from the graph of resistance vs pressure. The results obtained are discussed in detail. (author)

Some safety aspects of CO2 vapour compression systems

Energy Technology Data Exchange (ETDEWEB)

Pettersen, J. [Department of Refrigeration and Air Conditioning, Norwegian University of Science and Technology NTNU, Trondheim (Norway); Hafner, A.; Braanaas, M. [SINTEF Energy Research, Refrigeration and Air Conditioning, Trondheim (Norway)

2000-11-01

Since CO2 is a non-toxic and non-flammable refrigerant, the major safety issues for CO2 systems are related to the high operating pressure. In case of a component rupture, the explosion energy (stored energy) may characterise the extent of potential damage.The explosion energy can be estimated based on component (refrigerant-side) volumes, pressures and refrigerant property data. The explosion (stored) energies of baseline systems and CO2 systems are calculated and compared. Results show that the explosion energies are not as different as the large difference in pressure would indicate. It has been suggested that a Boiling Liquid Expanding Vapour Explosion (BLEVE) may occur when a vessel containing pressurised liquid or supercritical fluid is rapidly depressurised, e.g. due to a crack or a rupture. The overpressure from a BLEVE may be high enough to rupture the whole vessel, with a resulting blast wave and risk of flying fragments. Some tests on CO2 have been conducted at varying initial conditions and liquid fill levels, and with varying vent areas. No significant overpressure peaks above the initial pressure has been observed in the current test programme. 19 refs.

Medical cannabis use in Canada: vapourization and modes of delivery.

Science.gov (United States)

Shiplo, Samantha; Asbridge, Mark; Leatherdale, Scott T; Hammond, David

2016-10-29

The mode of medical cannabis delivery-whether cannabis is smoked, vapourized, or consumed orally-may have important implications for its therapeutic efficacy and health risks. However, there is very little evidence on current patterns of use among Canadian medical cannabis users, particularly with respect to modes of delivery. The current study examined modes of medical cannabis delivery following regulatory changes in 2014 governing how Canadians access medical cannabis. A total of 364 approved adult Canadian medical cannabis users completed an online cross-sectional survey between April and June 2015. The survey examined patterns of medical cannabis use, modes of delivery used, and reasons for use. Participants were recruited through a convenience sample from nine Health Canada licensed producers. Using a vapourizer was the most popular mode of delivery for medical cannabis (53 %), followed by smoking a joint (47 %). The main reason for using a vapourizer was to reduce negative health consequences associated with smoking. A majority of current vapourizer users reported using a portable vapourizer (67.2 %), followed by a stationary vapourizer (41.7 %), and an e-cigarette or vape pen (19.3 %). Current use of a vapourizer was associated with fewer respiratory symptoms (AOR = 1.28, 95 % CI 1.05-1.56, p = 0.01). The findings suggest an increase in the popularity of vapourizers as the primary mode of delivery among approved medical users. Using vapourizers has the potential to prevent some of the adverse respiratory health consequences associated with smoking and may serve as an effective harm reduction method. Monitoring implications of such current and future changes to medical cannabis regulations may be beneficial to policymakers.

Beam-profile monitor using a sodium-vapour

CERN Multimedia

1972-01-01

Beam-profile monitor using a sodium-vapour curtain at 45 degrees to the ISR beam in Ring I (sodium generator is in white cylinder just left of centre). Electrons produced by ionization of the sodium vapour give an image of the beam on a fluorescent screen that is observed by a TV camera (at upper right).

Hot-wire chemical vapour deposition of carbon nanotubes

CSIR Research Space (South Africa)

Cummings, FR

2006-07-01

Full Text Available ablation of graphite, carbon-arc discharge and chemical vapour deposition (CVD). However, some of these techniques have been shown to be expensive due to high deposition temperatures and are not easily controllable. Recently hot-wire chemical vapour...

Vapour liquid equilibria of monocaprylin plus palmitic acid or methyl stearate at P = (1.20 and 2.50) kPa by using DSC technique

International Nuclear Information System (INIS)

Cunico, Larissa P.; Damaceno, Daniela S.; Matricarde Falleiro, Rafael M.; Sarup, Bent; Abildskov, Jens; Ceriani, Roberta; Gani, Rafiqul

2015-01-01

Highlights: • Novel VLE data for binary mixtures involving a partial acylglycerol (monocaprylin). • Use of a promising technique for measuring VLE/vapour pressure data (DSC technique). • The consistency of experimental data is analysed by a proposed methodology. • Regressed parameters are given for excess Gibbs thermodynamic models. • New regressed parameters are presented for UNIFAC to account for nonidealities. - Abstract: The Differential Scanning Calorimetry (DSC) technique is used for measuring isobaric (vapour + liquid) equilibria for two binary mixtures: {monocaprylin + palmitic acid (system 1) or methyl stearate (system 2)} at two different pressures P = (1.20 and 2.50) kPa. The obtained PTx data are correlated by Wilson, NRTL and UNIQUAC models. The original UNIFAC group contribution method is also considered and new binary interaction parameters for the main groups CH 2 , CCOO, OH and COOH are regressed, to account for the non-idealities found in these lipid systems. Established thermodynamic consistency tests are applied and attest the quality of the measured data. In terms of relevance of the selected components, system 1 can be found in the purification and deodorization steps during the production of edible oils, while, system 2 can be found in the purification steps of biodiesel. It should be noted that no such data could be found in the open literature, not only for the specific components selected but also for the combination of the classes of components considered; that is, acylglycerol plus fatty acid or fatty ester.

Liquid assisted plasma enhanced chemical vapour deposition with a non-thermal plasma jet at atmospheric pressure

Czech Academy of Sciences Publication Activity Database

Schäfer, J.; Fricke, K.; Mika, Filip; Pokorná, Zuzana; Zajíčková, L.; Foest, R.

2017-01-01

Roč. 630, MAY 30 (2017), s. 71-78 ISSN 0040-6090 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : plasma jet * liquid assisted plasma enhanced chemical * vapour deposition * silicon oxide Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Coating and films Impact factor: 1.879, year: 2016

Pressure drop in two-phase He I natural circulation loop at low vapour quality

International Nuclear Information System (INIS)

Baudouy, B.

2003-01-01

Steady state pressure drop in a two-phase He I natural circulation loop has been measured at atmospheric pressure. Results are obtained up to 0.2 exit vapor quality for a 14-mm diameter copper tube heated over a length of 1.2 m. Pressure drop assessment, done with the momentum balance equation including subcooling, reveals that the homogeneous model and Friedel's friction multiplier associated with Huq and Loth's void fraction correlations predict data within 15%. (author)

Synthesis and investigation of saturated vapor pressure of lanthanum, praseodymium and neodymium tris-isopropylcyclopentadienyls

International Nuclear Information System (INIS)

Devyatykh, G.G.; Chernyaev, N.P.; Zverev, Yu.B.; Gavrishchuk, E.M.; Runovskaya, I.V.; Krupnova, Eh.F.; Chesnokova, S.G.

1980-01-01

Lanthanum, praseodymium and neodymium tris-isopropylcyclopentadienyls are synthesized with corresponding unhydrous chlorides in tetrahydrofuran solution. Saturated vapour pressure of substances obtained is studied in the 150-262 deg C range by the statistic method using a compensation zero-manometer. Vapour pressure of the compounds in question is shown to increase with the growth of the rare earth element number [ru

Measurement of the specific airway resistance by plethysmography in young children accompanied by an adult

DEFF Research Database (Denmark)

Klug, B; Bisgaard, H

1997-01-01

The purpose of this study was to evaluate a procedure for measurement of specific airway resistance (sRaw) by whole body plethysmography in young awake children accompanied by an adult. sRaw was measured by a single-step procedure, omitting the measurement of the thoracic gas volume. The frequency...... dependency of sRaw was investigated and the accuracy of simulating body temperature, atmospheric pressure and saturation with water vapour (BTPS) conditions by electronic compensation was assessed. One hundred and thirty one children with asthma were studied. In 57 children (mean (SD) age 5.6 (1.8) yrs) who....... In conclusion, the use of electronic compensation for simulating body temperature, atmospheric pressure and saturation with water vapour introduces a bias that affects the accuracy of the estimate of specific airway resistance. Nevertheless, plethysmographic measurements with and without an accompanying adult...

Medical cannabis use in Canada: vapourization and modes of delivery

Directory of Open Access Journals (Sweden)

Samantha Shiplo

2016-10-01

Full Text Available Abstract Background The mode of medical cannabis delivery—whether cannabis is smoked, vapourized, or consumed orally—may have important implications for its therapeutic efficacy and health risks. However, there is very little evidence on current patterns of use among Canadian medical cannabis users, particularly with respect to modes of delivery. The current study examined modes of medical cannabis delivery following regulatory changes in 2014 governing how Canadians access medical cannabis. Methods A total of 364 approved adult Canadian medical cannabis users completed an online cross-sectional survey between April and June 2015. The survey examined patterns of medical cannabis use, modes of delivery used, and reasons for use. Participants were recruited through a convenience sample from nine Health Canada licensed producers. Results Using a vapourizer was the most popular mode of delivery for medical cannabis (53 %, followed by smoking a joint (47 %. The main reason for using a vapourizer was to reduce negative health consequences associated with smoking. A majority of current vapourizer users reported using a portable vapourizer (67.2 %, followed by a stationary vapourizer (41.7 %, and an e-cigarette or vape pen (19.3 %. Current use of a vapourizer was associated with fewer respiratory symptoms (AOR = 1.28, 95 % CI 1.05–1.56, p = 0.01. Conclusions The findings suggest an increase in the popularity of vapourizers as the primary mode of delivery among approved medical users. Using vapourizers has the potential to prevent some of the adverse respiratory health consequences associated with smoking and may serve as an effective harm reduction method. Monitoring implications of such current and future changes to medical cannabis regulations may be beneficial to policymakers.

Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism

Directory of Open Access Journals (Sweden)

Adnan Mujahid

2010-05-01

Full Text Available Cholesteric liquid crystals (CLCs are used as sensitive coatings for the detection of organic solvent vapours for both polar and non-polar substances. The incorporation of different analyte vapours in the CLC layers disturbs the pitch length which changes the optical properties, i.e., shifting the absorption band. The engulfing of CLCs around non-polar solvent vapours such as tetrahedrofuran (THF, chloroform and tetrachloroethylene is favoured in comparison to polar ones, i.e., methanol and ethanol. Increasing solvent vapour concentrations shift the absorbance maximumto smaller wavelengths, e.g., as observed for THF. Additionally, CLCs have been coated on acoustic devices such as the quartz crystal microbalance (QCM to measure the frequency shift of analyte samples at similar concentration levels. The mass effect for tetrachloroethylene was about six times higher than chloroform. Thus, optical response can be correlated with intercalation in accordance to mass detection. The mechanical stability was gained by combining CLCs with imprinted polymers. Therefore, pre-concentration of solvent vapours was performed leading to an additional selectivity.

Pressure drop in two-phase He I natural circulation loop at low vapour quality

Energy Technology Data Exchange (ETDEWEB)

Baudouy, B

2003-01-01

Steady state pressure drop in a two-phase He I natural circulation loop has been measured at atmospheric pressure. Results are obtained up to 0.2 exit vapor quality for a 14-mm diameter copper tube heated over a length of 1.2 m. Pressure drop assessment, done with the momentum balance equation including subcooling, reveals that the homogeneous model and Friedel's friction multiplier associated with Huq and Loth's void fraction correlations predict data within 15%. (author)

Vapour pressures and osmotic coefficients of binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate and 1-ethyl-3-methylpyridinium ethylsulfate with alcohols at T = 323.15 K

International Nuclear Information System (INIS)

Calvar, Noelia; Gonzalez, Begona; Dominguez, Angeles; Macedo, Eugenia A.

2009-01-01

Osmotic coefficients of binary mixtures containing alcohols (ethanol, 1-propanol, and 2-propanol) and the ionic liquids 1-ethyl-3-methylimidazolium ethylsulfate and 1-ethyl-3-methylpyridinium ethylsulfate were determined at T = 323.15 K. Vapour pressure and activity coefficients of the studied systems were calculated from experimental data. The extended Pitzer model modified by Archer, and the modified NRTL model (MNRTL) were used to correlate the experimental data, obtaining standard deviations lower than 0.012 and 0.031, respectively. The mean molal activity coefficients and the excess Gibbs free energy of the studied binary mixtures were calculated from the parameters obtained with the extended Pitzer model of Archer.

Analysing the mechanisms of soil water and vapour transport in the desert vadose zone of the extremely arid region of northern China

Science.gov (United States)

Du, Chaoyang; Yu, Jingjie; Wang, Ping; Zhang, Yichi

2018-03-01

The transport of water and vapour in the desert vadose zone plays a critical role in the overall water and energy balances of near-surface environments in arid regions. However, field measurements in extremely dry environments face many difficulties and challenges, so few studies have examined water and vapour transport processes in the desert vadose zone. The main objective of this study is to analyse the mechanisms of soil water and vapour transport in the desert vadose zone (depth of ∼350 cm) by using measured and modelled data in an extremely arid environment. The field experiments are implemented in an area of the Gobi desert in northwestern China to measure the soil properties, daily soil moisture and temperature, daily water-table depth and temperature, and daily meteorological records from DOYs (Days of Year) 114-212 in 2014 (growing season). The Hydrus-1D model, which simulates the coupled transport of water, vapour and heat in the vadose zone, is employed to simulate the layered soil moisture and temperature regimes and analyse the transport processes of soil water and vapour. The measured results show that the soil water and temperatures near the land surface have visible daily fluctuations across the entire soil profile. Thermal vapour movement is the most important component of the total water flux and the soil temperature gradient is the major driving factor that affects vapour transport in the desert vadose zone. The most active water and heat exchange occurs in the upper soil layer (depths of 0-25 cm). The matric potential change from the precipitation mainly re-draws the spatio-temporal distribution of the isothermal liquid water in the soil near the land surface. The matric potential has little effect on the isothermal vapour and thermal liquid water flux. These findings offer new insights into the liquid water and vapour movement processes in the extremely arid environment.

No sodium in the vapour plumes of Enceladus.

Science.gov (United States)

Schneider, Nicholas M; Burger, Matthew H; Schaller, Emily L; Brown, Michael E; Johnson, Robert E; Kargel, Jeffrey S; Dougherty, Michele K; Achilleos, Nicholas A

2009-06-25

The discovery of water vapour and ice particles erupting from Saturn's moon Enceladus fuelled speculation that an internal ocean was the source. Alternatively, the source might be ice warmed, melted or crushed by tectonic motions. Sodium chloride (that is, salt) is expected to be present in a long-lived ocean in contact with a rocky core. Here we report a ground-based spectroscopic search for atomic sodium near Enceladus that places an upper limit on the mixing ratio in the vapour plumes orders of magnitude below the expected ocean salinity. The low sodium content of escaping vapour, together with the small fraction of salt-bearing particles, argues against a situation in which a near-surface geyser is fuelled by a salty ocean through cracks in the crust. The lack of observable sodium in the vapour is consistent with a wide variety of alternative eruption sources, including a deep ocean, a freshwater reservoir, or ice. The existing data may be insufficient to distinguish between these hypotheses.

Prediction of vapour-liquid and vapour-liquid-liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators

Science.gov (United States)

Narayanan, Vineed; Venkatarathnam, G.

2018-03-01

Nitrogen-hydrocarbon mixtures are widely used as refrigerants in J-T refrigerators operating with mixtures, as well as in natural gas liquefiers. The Peng-Robinson equation of state has traditionally been used to simulate the above cryogenic process. Multi parameter Helmholtz energy equations are now preferred for determining the properties of natural gas. They have, however, been used only to predict vapour-liquid equilibria, and not vapour-liquid-liquid equilibria that can occur in mixtures used in cryogenic mixed refrigerant processes. In this paper the vapour-liquid equilibrium of binary mixtures of nitrogen-methane, nitrogen-ethane, nitrogen-propane, nitrogen-isobutane and three component mixtures of nitrogen-methane-ethane and nitrogen-methane-propane have been studied with the Peng-Robinson and the Helmholtz energy equations of state of NIST REFPROP and compared with experimental data available in the literature.

Sampling system of atmospheric water vapour for analysis of the γ sub(D) relationship

International Nuclear Information System (INIS)

Foloni, L.L.; Villa Nova, N.A.; Salati, E.

1979-01-01

The development of a system to water vapour air, for natural isotopic composition analysis of hydrogen is presented. The system uses molecular sieve, type '4A', without cooling agent and permits the choice of a sampling time, variyng from a few minutes to many hours, through the control of the admission of vapour flux. The system has good performance in field conditions, with errors of the order of + -3,0 0 /00 in the γ sub(D)( 0 /00) measurements [pt

Optical measurements for the gaseous phase speciation of HIx mixtures: experiments and modelling

International Nuclear Information System (INIS)

Denis Doizi; Vincent Dauvois; Vincent Delanne; Jean Luc Roujou; Bruno Larousse; Olivier Hercher; Christophe Moulin; Pierre Fauvet; P Carles; Jean Michel Hartmann

2006-01-01

To design and optimize the efficiency of the reactive distillation column of HI we have proposed for the HI section of the I-S cycle, analytical optical 'online' techniques have been proposed to measure the partial and total pressures of the liquid vapour equilibrium of the ternary HI/I 2 /H 2 O mixtures: - FTIR spectrometry for the measurement of hydrogen iodide and water vapours, - Visible spectrometry for the measurement of iodine vapour. The use of these optical techniques has been validated in an experimental device around 130 C and 2 bars. This device is composed of a glass cell equipped with two optical path lengths and placed in a thermo-regulated oven to allow the optical measurements of the concentrations of the three species in the vapour phase. Using an experimental design analysis, the infrared spectra of hydrogen iodide and water have been measured in a selected wavelength range versus temperature and for different HI x compositions. The spectra are then analyzed in particular using a model especially developed for this objective. This model relies on the fitting of the experimental infrared data using a root mean square method and an appropriate spectroscopic database. The visible spectrum of iodine has also been measured. (authors)

Analysis of laser-induced evaporation of Al target under conditions of vapour plasma formation

International Nuclear Information System (INIS)

Mazhukin, V.I.; Nossov, V.V.; Smurov, I.

2004-01-01

The plasma-controlled evaporation of the Al target induced by the laser pulse with intensity of 10 9 W/cm 2 and wavelength of 1.06 μm is analysed with account for the two-dimensional effects. The self consistent model is applied, including the heat transfer equation in condensed medium, the equations of radiation gas dynamics in evaporated substance and the Knudsen layer model at the two media boundary. It is found that the phase transition at the target surface is controlled by the two factors: the surface temperature that depends on the transmitted radiation intensity, and the plasma pressure, governed by the expansion regime. The process comes through three characteristic stages, the sonic evaporation at the beginning, the condensation during the period of plasma formation and initial expansion, and finally, the re-start of evaporation in subsonic regime after the partial brightening of the plasma. During the subsonic evaporation stage the vapour flow and the mass removal rate are much higher near the beam boundaries than in the centre due to smaller plasma counter-pressure. The vapour plasma pattern is characterised by the dense hot zone near the surface where the absorption of laser energy occurs, and rapid decrease of density outside the zone due to three-dimensional expansion

Self-contained high-pressure chambers for study on the Moessbauer effect at low temperatures

International Nuclear Information System (INIS)

Stepanov, G.N.

1980-01-01

Designs of two high-pressure chambers intended for studying the Moessbauer effect at low temperatures are described. The high-pressure chamber of the Bridgman anvil type is made of non magnetic materials and intended for operation at helium temperatures. The chamber employs a superconducting pressure gage. A sample and superconducting pressure gage are surrounded with a liquid medium of a high pressure at a room temperature. Measurements of the pressure were taken during heating the chamber in the vapours of liquid helium according to the known dependence of the lead superconducting transition temperature on pressure. The other high-pressure chamber of the piston-to-cylinder type can be used to study the Moessbauer effect at temperatures ranging from 4 to 300 K. Pressure in the chamber is measured by means of the superconducting pressure gage. The maximum pressure obtained in the chamber constitutes 25 kbar

Ethanol vapour sensing properties of screen printed WO 3 thick films

Indian Academy of Sciences (India)

The ethanol vapour sensing properties of these thick films were investigated at different operating temperatures and ethanol vapour concentrations. The WO3 thick films exhibit excellent ethanol vapour sensing properties with a maximum sensitivity of ∼1424.6% at 400°C in air atmosphere with fast response and recovery ...

Near-infrared water vapour self-continuum at close to room temperature

International Nuclear Information System (INIS)

Ptashnik, I.V.; Petrova, T.M.; Ponomarev, Yu.N.; Shine, K.P.; Solodov, A.A.; Solodov, A.M.

2013-01-01

The gaseous absorption of solar radiation within near-infrared atmospheric windows in the Earth's atmosphere is dominated by the water vapour continuum. Recent measurements by Baranov et al. (2011) [17] in 2500 cm −1 (4 μm) window and by Ptashnik et al. (2011) [18] in a few near-infrared windows revealed that the self-continuum absorption is typically an order of magnitude stronger than given by the MT C KD continuum model prior to version 2.5. Most of these measurements, however, were made at elevated temperatures, which makes their application to atmospheric conditions difficult. Here we report new laboratory measurements of the self-continuum absorption at 289 and 318 K in the near-infrared spectral region 1300–8000 cm −1 , using a multipass 30 m base cell with total optical path 612 m. Our results confirm the main conclusions of the previous measurements both within bands and in windows. Of particular note is that we present what we believe to be the first near-room temperature measurement using Fourier Transform Spectrometry of the self-continuum in the 6200 cm −1 (1.6 μm) window, which provides tentative evidence that, at such temperatures, the water vapour continuum absorption may be as strong as it is in 2.1 μm and 4 μm windows and up to 2 orders of magnitude stronger than the MT C KD-2.5 continuum. We note that alternative methods of measuring the continuum in this window have yielded widely differing assessment of its strength, which emphasises the need for further measurements. -- Highlights: ► New lab measurements of the near-infrared water vapour self-continuum absorption. ► First room-temperature data on the self-continuum in the 1.6 μm window. ► In the 1.6 μm window the new data exceed MT C KD-2.5 model by 2 orders of magnitude

Determination and modelling of osmotic coefficients and vapour pressures of binary systems 1- and 2-propanol with CnMimNTf2 ionic liquids (n = 2, 3, and 4) at T = 323.15 K

International Nuclear Information System (INIS)

Calvar, Noelia; Gomez, Elena; Dominguez, Angeles; Macedo, Eugenia A.

2011-01-01

Highlights: → Osmotic coefficients of 1- and 2-propanol with C n MimNTf 2 (n = 2, 3, and 4) are determined. → Experimental data were correlated with extended Pitzer model of Archer and MNRTL. → Mean molal activity coefficients and excess Gibbs free energies were calculated. → Effect of the anion is studied comparing these results with literature. - Abstract: The osmotic and activity coefficients and vapour pressures of binary mixtures containing 1-propanol, or 2-propanol and imidazolium-based ionic liquids with bis(trifluoromethylsulfonyl)imide as anion (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, C 2 MimNTf 2 , 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, C 3 MimNTf 2 , and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, C 4 MimNTf 2 ) were determined at T = 323.15 K using the vapour pressure osmometry technique. The experimental osmotic coefficients were correlated using the extended Pitzer model modified by Archer and the MNRTL model, obtaining standard deviations lower than 0.033 and 0.064, respectively. The mean molal activity coefficients and the excess Gibbs free energy for the mixtures studied were calculated from the parameters of the extended Pitzer model modified by Archer. Besides the effect of the alkyl-chain of the cation, the effect of the anion can be assessed comparing the experimental results with those previously obtained for imidazolium ionic liquids with sulphate anions.

LOFT fuel rod pressure measurement

International Nuclear Information System (INIS)

Billeter, T.R.

1979-01-01

Pressure sensors selected for measuring fuel rod pressure within the LOFT reactor exhibited stable, repeatable operating characteristics during calibrations at temperatures up to 800 0 F and pressures to 2500 psig. All sensors have a nominal sensitivity of .5 millivolts per psi, decreasing monotonically with temperature. Output signal increases linearly with increasing pressure up to 2000 psig. For imposed slow and rapid temperature variations and for pressure applied during these tests, the sensor indicates a pressure at variance with the actual value by up to 15% of reading. However, the imposed temperature rates of change often exceeded the value of -10 0 F/sec. specified for LOFT. The series of tests in an autoclave permit creation of an environment most closely resembling sensor operating conditions within LOFT. For multiple blowdowns and for longtime durations the sensor continued to provide pressure-related output signals. For temperature rates up to -87 0 F/sec, the indicated pressure measurement error remained less than 13% of reading. Adverse effects caused by heating the 1/16 inch O.D. signal cable to 800 0 F contributed only insignificantly to the noted pressure measurement error

The volatile pivalates of Y, Ba and Cu as prospective precursors for metal-organic chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Iljina, E. (Dept. of Chemistry, Moscow State Univ. (Russian Federation)); Korjeva, A. (Dept. of Chemistry, Moscow State Univ. (Russian Federation)); Kuzmina, N. (Dept. of Chemistry, Moscow State Univ. (Russian Federation)); Troyanov, S. (Dept. of Chemistry, Moscow State Univ. (Russian Federation)); Dunaeva, K. (Dept. of Chemistry, Moscow State Univ. (Russian Federation)); Martynenko, L. (Dept. of Chemistry, Moscow State Univ. (Russian Federation))

1993-04-15

The volatile pivalates of Y, Ba and Cu were synthesized and characterized by chemical and thermogravimetric analysis, IR spectroscopy, X-ray diffraction and mass spectrometry. The volatilities of metal pivalates was studied; the vapour pressures, thermodynamic characteristics and rates of sublimation were investigated. The volatile pivalates of Y, Ba and Cu are new prospective accessible compounds. (orig.)

Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells

Science.gov (United States)

Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; Förste, Juliane; Danzl, Katarina; Messner, Barbara; Bernhard, David

2016-01-01

The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs) to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity. PMID:27351725

Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells.

Science.gov (United States)

Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; Förste, Juliane; Danzl, Katarina; Messner, Barbara; Bernhard, David

2016-01-01

The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs) to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity.

Vapours of US and EU Market Leader Electronic Cigarette Brands and Liquids Are Cytotoxic for Human Vascular Endothelial Cells.

Directory of Open Access Journals (Sweden)

Raphaela Putzhammer

Full Text Available The present study was conducted to provide toxicological data on e-cigarette vapours of different e-cigarette brands and liquids from systems viewed as leaders in the e-cigarette market and to compare e-cigarette vapour toxicity to the toxicity of conventional strong high-nicotine cigarette smoke. Using an adapted version of a previously constructed cigarette smoke constituent sampling device, we collected the hydrophilic fraction of e-cigarette vapour and exposed human umbilical vein endothelial cells (HUVECs to the mixture of compounds present in the vapour of 4 different single-use e-cigarettes, 6 different liquid vapours produced by the same refillable e-cigarette, and one e-cigarette with an exchangeable liquid cartridge. After incubation of cells with various concentrations and for various periods of time we analysed cell death induction, proliferation rates, the occurrence of intra-cellular reactive oxygen species, cell morphology, and we also measured e-cigarette heating coil temperatures. Overall, conventional cigarette smoke extract showed the most severe impact on endothelial cells. However, some e-cigarette vapour extracts showed high cytotoxicity, inhibition of cell proliferation, and alterations in cell morphology, which were comparable to conventional high-nicotine cigarettes. The vapours generated from different liquids using the same e-cigarette show substantial differences, pointing to the liquids as an important source for toxicity. E-cigarette vapour-mediated induction of oxidative stress was significant in one out of the 11 analysed vapours. There is a high variability in the acute cytotoxicity of e-cigarette vapours depending on the liquid and on the e-cigarettes used. Some products showed toxic effects close to a conventional high-nicotine cigarette. Liquid nicotine, menthol content, and the formation of acute intracellular reactive oxygen species do not seem to be the central elements in e-cigarette vapour toxicity.

Considering the use of polyethylene vapour barriers in temperate climates

Energy Technology Data Exchange (ETDEWEB)

Lawton, M.D. [Morrison Hershfield Ltd., Vancouver, BC (Canada); Brown, W.C. [Morrison Hershfield Ltd., Ottawa, ON (Canada)

2003-07-01

Most building envelope assemblies in Canada must include a vapour barrier in order to comply with Canadian building codes. The installation of sheet polyethylene between the studs and the interior sheathing has been the most common method because it provides more diffusion resistance than necessary to control condensation within a building envelope assembly. It has been suggested that the presence of a polyethylene vapour barrier on the warm-in-winter side of the insulation may actually cause moisture problems because a very low permeance material increases average moisture levels. This paper examined the theory that a vapour barrier at this location restricts drying of moisture that enters the building from outside. Pacific coastal regions of Canada and the United States were presented as examples. Other ways that a polyethylene vapour barrier affects wall performance were also presented. The advanced hygrothermal model HygIRC, developed by Canada's National Research Council, was used to simulate the performance of a wall assembly. Results indicate that eliminating the low permeance polyethylene vapour barrier does not necessarily reduce the risk of moisture problems. Removal of the vapour barrier may have some negative effects, such as increased risk of periodic moisture accumulation and mold growth on paper-faced gypsum board. 7 refs., 2 tabs., 7 figs.

Detection of polar vapours

International Nuclear Information System (INIS)

Blyth, D.A.

1980-01-01

Apparatus for monitoring for polar vapours in a gas consists of (i) a body member defining a passage through which a continuous stream of the gas passes; (ii) an ionising source associated with a region of the passage such that ionization of the gas stream takes place substantially only within the region and also any polar vapour molecules present therein will react with the gas formed to generate ion clusters; and (iii) an electrode for collecting ions carried by the gas stream, the electrode being positioned in the passage downstream of the region and separated from the region by a sufficient distance to ensure that no substantial number of the gas ions formed in said region remains in the gas stream at the collector electrode whilst ensuring that a substantial proportion of the ion clusters formed in the region does remain in the gas stream at the collector electrode. (author)

The millennium water vapour drop in chemistry–climate model simulations

Directory of Open Access Journals (Sweden)

S. Brinkop

2016-07-01

Full Text Available This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop" and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM EMAC (ECHAM/MESSy Atmospheric Chemistry Model. The model simulations differ with respect to the prescribed sea surface temperatures (SSTs and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer–Dobson circulation (BDC. We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST changes due to a coincidence with a preceding strong El Niño–Southern Oscillation event (1997/1998 followed by a strong La Niña event (1999/2000 and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO in 2000. Correct (observed SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics

Pulsed operation of high-pressure-sodium discharge lamps

International Nuclear Information System (INIS)

Guenther, K.; Kloss, H.G.; Lehmann, T.; Radtke, R.; Serick, F.

1990-01-01

Results of spectral and photometric measurements are presented for pulsed operated high-pressure-sodium lamps. Choosing for the colour temperature a value of 3000 K, the output spectrum was optimized with respect to colour rendition and lamp efficacy taking the pulse parameters, the sodium mole fraction, and the cold spot temperature as quantities to be varied. For the nominal rating of 70 W a maximum lamp efficacy of 70 lm/W and a colour rendering index of 40 can be obtained. Further improvements of the colour rendition require an enhanced sodium vapour pressure which can be achieved by operating the lamp at rised cold spot temperature. (orig.)

Pulsed operation of high-pressure-sodium discharge lamps

Energy Technology Data Exchange (ETDEWEB)

Guenther, K; Kloss, H G; Lehmann, T [Zentrum fuer Forschung und Technologie, Berlin (Germany, F.R.); Radtke, R; Serick, F [Zentralinstitut fuer Elektronenphysik, Berlin (Germany, F.R.)

1990-01-01

Results of spectral and photometric measurements are presented for pulsed operated high-pressure-sodium lamps. Choosing for the colour temperature a value of 3000 K, the output spectrum was optimized with respect to colour rendition and lamp efficacy taking the pulse parameters, the sodium mole fraction, and the cold spot temperature as quantities to be varied. For the nominal rating of 70 W a maximum lamp efficacy of 70 lm/W and a colour rendering index of 40 can be obtained. Further improvements of the colour rendition require an enhanced sodium vapour pressure which can be achieved by operating the lamp at rised cold spot temperature. (orig.).

Carbon structures formation in low current high voltage electrical discharge in hydrocarbon vapours

International Nuclear Information System (INIS)

Sobczyk, A T; Jaworek, A

2011-01-01

The properties of carbon fibers and other carbon structures produced from hydrocarbon vapours decomposed in electrically generated plasma at atmospheric pressure are studied in this paper. The electrical discharge was generated between a stainless steel needle and a plate made of nickel alloy. The carbon fiber has grown at the tip of the needle electrode, while other microflower-like deposits were built at the plate. The physical properties of carbon fibers were investigated by SEM, Raman spectroscopy, XRD, and EDS methods.

Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

Directory of Open Access Journals (Sweden)

N. David

2009-04-01

Full Text Available We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks.

Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition – many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both may also interfere with the ability to conduct accurate measurements.

We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements, the other in central Israel (29 measurements. The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences

Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

Science.gov (United States)

David, N.; Alpert, P.; Messer, H.

2009-04-01

We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements), the other in central Israel (29 measurements). The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences (RMSD) were 1.8 g/m3 and 3.4 g/m3 for

A lidar for water vapour measurements in daytime at Lampedusa, Italy

Directory of Open Access Journals (Sweden)

F. Marenco

2003-06-01

Full Text Available ENEA is planning to develop a lidar system for measurement of the vertical profi le of water vapour mixing ratio in daytime at a remote site, the Station for Climate Observations located in Lampedusa, Italy. The Raman lidar technique has been retained because of its experimental simplicity with respect to DIAL, and the UV spectral range has been chosen because Raman cross-sections and detector effi ciencies are larger. For a wavelength larger than ~ 300 nm the signal is limited in daytime by sky background, but extinction is acceptable, and the aims of the system can be reached with a strong laser source. The 355 nm wavelength of a frequency-tripled Nd:YAG laser has been retained as this laser source permits to reach a large pulse energy while keeping the system simple to operate. Geometrical form factor calculations need to be performed to evaluate the near-range overlap between the laser beam and the fi eld-of-view of the receiver. Among several options, a dual-receiver system has been retained to account for the several orders of magnitude expected in the backscattered signal intensity: a smaller receiver, with a primary mirror of 200 mm diameter for the 0.2-1 km range, and a larger 500 mm receiver for the 1-3 km range.

Analysis of a combined Rankine-vapour-compression refrigeration cycle

International Nuclear Information System (INIS)

Aphornratana, Satha; Sriveerakul, Thanarath

2010-01-01

This paper describes a theoretical analysis of a heat-powered refrigeration cycle, a combined Rankine-vapour-compression refrigeration cycle. This refrigeration cycle combines an Organic Rankine Cycle and a vapour-compression cycle. The cycle can be powered by low grade thermal energy as low as 60 deg. C and can produce cooling temperature as low as -10 deg. C. In the analysis, two combined Rankine-vapour-compression refrigeration cycles were investigated: the system with R22 and the system with R134a. Calculated COP values between 0.1 and 0.6 of both the systems were found.

Remediation of sandy soils contaminated with hydrocarbons and halogenated hydrocarbons by soil vapour extraction.

Science.gov (United States)

Albergaria, José Tomás; Alvim-Ferraz, Maria da Conceição M; Delerue-Matos, Cristina

2012-08-15

This paper presents the study of the remediation of sandy soils containing six of the most common contaminants (benzene, toluene, ethylbenzene, xylene, trichloroethylene and perchloroethylene) using soil vapour extraction (SVE). The influence of soil water content on the process efficiency was evaluated considering the soil type and the contaminant. For artificially contaminated soils with negligible clay contents and natural organic matter it was concluded that: (i) all the remediation processes presented efficiencies above 92%; (ii) an increase of the soil water content led to a more time-consuming remediation; (iii) longer remediation periods were observed for contaminants with lower vapour pressures and lower water solubilities due to mass transfer limitations. Based on these results an easy and relatively fast procedure was developed for the prediction of the remediation times of real soils; 83% of the remediation times were predicted with relative deviations below 14%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Measurements of Pressure of Extracorporeal Shock Wave Lithotripter Using Pressure-Sensitive Papers

Science.gov (United States)

Inose, Naoto; Ide, Masao

1993-05-01

This paper describes measurements of pressures at the focal region of the extracorporeal shock wave lithotripter (ESWL) using pressure-sensitive papers. At the focal region of ESWL, ordinary hydrophones are quickly damaged, because of very high pressures. Recently, measurements of pressure at the focal region of ESWL using pressure-sensitive paper have been advised. Therefore, we have studied the effectiveness of pressure-sensitive papers in the measurement of high acoustic pressures at the focal region of ESWL.

Measurements to check vapour recovery systems of public retail stations in Hamburg (Phase 1); Messaktion zur Ueberpruefung von Gasrueckfuehrungssystemen an oeffentlichen Tankstellen in der Freien und Hansestadt Hamburg (Phase 1)

Energy Technology Data Exchange (ETDEWEB)

Altmann, B.R. [Deutsche Wissenschaftliche Gesellschaft fuer Erdoel, Erdgas und Kohle e.V., Hamburg (Germany); Golgert, R. [Gesundheits- und Umweltamt, Hamburg (Germany). Bezirksamt Wandsbek; Okelmann, J. [Umweltbehoerde, Hamburg (Germany). Amt fuer Immissionsschutz und Betriebe; Schenck, H.G. [Gesundheits- und Umweltamt, Hamburg (Germany). Bezirksamt Eimsbuettel, Abt. fuer Umweltschutz

2000-06-01

DGMK jointly with the local authorities of health and environment, in close co-operation with the environmental authorities of the city of Hamburg, are thoroughly examining the vapour recovery systems at all public service stations in Hamburg. In phase I 50 sites were examined in August/September 1999 by several measuring methods called liquid-measurement, liquid-check, quick-check (UPA 50/Flo-Tester) and dry-measurement procedure. They delivered proportions and causes of bad performing and defective devices leading to appropriate maintenance. The dry-measurement procedure commonly used with regular checks by itself is not satisfactory to prove overall performance of the vapour recovery equipment. It should always be supplemented by a liquid-check procedure in order to ensure that the assigned vapour pumps work. As the dry-measurement procedure simulates a fuel flow it cannot detect such defects. Complete breakdowns of vapour recovery systems can be localised reliably with the quick check devices UPA 50/Flo-Tester. But due to high error tolerances, quick check devices are not suitable for quantitative measurement of vapour recovery rates on service stations. (orig.) [German] Die DGMK fuehrt unter Beteiligung der Umweltbehoerde Hamburg zusammen mit den Gesundheits- und Umweltaemtern der Bezirke und den Tankstellenbetreibern in einem Gemeinschaftsprojekt detaillierte Untersuchungen der Gasrueckfuehrungssysteme an allen Hamburger Tankstellen durch. Ziel der Untersuchung ist die Ueberpruefung und Verbesserung des technischen Zustandes der Gasrueckfuehrsysteme an allen Hamburger Tankstellen. Darueber hinaus sollen genaue Kenntnisse ueber die Verlaesslichkeit von gaengigen Messverfahren zur Ueberpruefung von Gasrueckfuehrsystemen erworben werden. In der Phase I wurden an 50 Tankstellen Messungen im August/September 1999 unter Anwendung des Nassmessverfahrens, des Trockenmessverfahrens, der Schnelltester (Flo-Tester und UPA 50) sowie der Nasskontrolle zur Ueberpruefung

Standard values of fugacity for sulfur which are self-consistent with the low-pressure phase diagram

Energy Technology Data Exchange (ETDEWEB)

Marriott, Robert A., E-mail: rob.marriott@ucalgary.ca [Alberta Sulphur Research Ltd., University of Calgary, Alberta (Canada); Wan, Herman H. [Alberta Sulphur Research Ltd., University of Calgary, Alberta (Canada)

2011-08-15

Highlights: > We have provided a method for calculating the fugacity for elemental sulfur. > Calculated sulfur fugacities can be used in sulfur equilibrium models. > The sulfur fugacities also can be used to locate the phase changes in the low-pressure phase diagram. > We have measured the 'natural' melting point of sulfur, and found it to be T = 388.5 {+-} 0.2 K. - Abstract: A method for calculating the fugacity of pure sulfur in the {alpha}-solid, {beta}-solid and liquid phase regions has been reported for application to industrial equilibrium conditions, e.g., high-pressure solubility of sulfur in sour gas. The fugacity calculations are self-consistent with the low-pressure phase diagram. As recently discussed by Ferreira and Lobo , empirical fitting of the experimental data does not yield consistent behaviour for the low-pressure phase diagram of elemental sulfur. In particular, there is a discrepancy between the vapour pressure of {beta}-solid (monoclinic) and liquid sulfur at the fusion temperature. We have provided an alternative semi-empirical approach which allows one to calculate values of the fugacity at conditions removed from the conditions of the pure sulfur phase transitions. For our approach, we have forced the liquid vapour pressure to equal the {beta}-solid vapour pressure at the {beta}-l-g triple point corresponding to the 'natural' fusion temperature for {beta}-solid. Many studies show a higher 'observed' fusion temperature for elemental sulfur. The non-reversible conditions for 'observed' fusion conditions for elemental sulfur result from a kinetically hindered melt which causes some thermodynamic measurements to be related to a metastable S{sub 8} liquid. We have measured the 'natural' fusion temperature, T{sub fus}{sup {beta}}(exp.)=(388.5{+-}0.2)K at p = 89.9 kPa, which is consistent with literature fusion data at higher-pressures. Using our semi-empirical approach, we have used or found the

Review of optimum temperature, humidity, and vapour pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review

Science.gov (United States)

Shamshiri, Redmond Ramin; Jones, James W.; Thorp, Kelly R.; Ahmad, Desa; Man, Hasfalina Che; Taheri, Sima

2018-04-01

Greenhouse technology is a flexible solution for sustainable year-round cultivation of Tomato (Lycopersicon esculentum Mill), particularly in regions with adverse climate conditions or limited land and resources. Accurate knowledge about plant requirements at different growth stages, and under various light conditions, can contribute to the design of adaptive control strategies for a more cost-effective and competitive production. In this context, different scientific publications have recommended different values of microclimate parameters at different tomato growth stages. This paper provides a detailed summary of optimal, marginal and failure air and root-zone temperatures, relative humidity and vapour pressure deficit for successful greenhouse cultivation of tomato. Graphical representations of the membership function model to define the optimality degrees of these three parameters are included with a view to determining how close the greenhouse microclimate is to the optimal condition. Several production constraints have also been discussed to highlight the short and long-term effects of adverse microclimate conditions on the quality and yield of tomato, which are associated with interactions between suboptimal parameters, greenhouse environment and growth responses.

Analysis of Water Vapour Flux Between Alpine Wetlands Underlying the Surface and Atmosphere in the Source Region of the Yellow River

Science.gov (United States)

Xie, Y.; Wen, J.; Liu, R.; Wang, X.; JIA, D.

2017-12-01

Wetland underlying surface is sensitive to climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Previous studies, which focused on the forest, grassland and farmland ecosystems, lack research on the alpine wetlands. In addition, research on the environmental control mechanism of latent heat flux is still qualitative and lacks quantitative evaluations and calculations. Using data from the observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors (solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows: Due to the diurnal variations of solar radiation and wind speed, the diurnal variations of the Ω factor present a trend in which the Ω factor are small in the morning and large in the evening. Due to the vegetation growing cycle, the seasonal variations of the Ω factor present a reverse "U" trend . These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over the latent heat flux. This conforms to omega theory. The values for average absolute atmospheric factor (surface factor or total ) control exercised by solar radiation and water vapour pressure are 0.20 (0.02 or 0.22 ) and 0.005 (-0.07 or -0.06) W·m-2·Pa-1, respectively.. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on the latent heat flux. The average Ω factor is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between the

Vapour transport growth of ZnO nanorods

Energy Technology Data Exchange (ETDEWEB)

Mofor, A.C.; Bakin, A.S.; Elshaer, A.; Waag, A. [Technical University Braunschweig, Institute of Semiconductor Technology, Braunschweig (Germany); Fuhrmann, D.; Hangleiter, A. [Technical University Braunschweig, Institute of Applied Physics, Braunschweig (Germany); Bertram, F.; Christen, J. [University of Magdeburg, Department of Solid State Physics, Magdeburg (Germany)

2007-07-15

The fabrication of low-dimensional ZnO structures has attracted enormous attention as such nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Many reported fabrication methods, especially for ZnO nanorods are mostly based on catalyst-assisted growth techniques that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on catalyst-free vapour-phase epitaxy growth of ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3} using purely elemental sources at relatively low temperatures and growth pressure. ZnO nanorods with widths of 80-900 nm and lengths of up to 12 {mu}m were obtained. Nanorod density on the order of 10{sup 9} cm{sup -2} with homogenous luminescence and high purity was also noted. (orig.)

Effect of paint on vapour resistivity in plaster

Directory of Open Access Journals (Sweden)

de Villanueva, L.

2008-12-01

Full Text Available The vapour resistivity of plaster coatings such as paint and their effectiveness as water repellents were studied in several types of plaster. To this end, painted, unpainted and pigmented specimens were tested. Experimental values were collected on diffusion and vapour permeability, or its inverse, water vapour resistivity.The data obtained were very useful for evaluating moisture exchange between plaster and the surrounding air, both during initial drying and throughout the life of the material. They likewise served as a basis for ensuring the proper evacuation of water vapour in walls, and use of the capacity of the porous network in plaster products to regulate moisture content or serve as a water vapour barrier to avoid condensation.Briefly, the research showed that pigments, water-based paints and silicon-based water repellents scantly raised vapour resistance. Plastic paints, enamels and lacquers, however, respectively induced five-, ten- and twenty-fold increases in vapour resistivity, on average.Se estudia el fenómeno de la resistividad al vapor de los de yeso y el efecto impermeabilizante que producen los recubrimientos de pintura sobre diversos tipos de yeso y escayola. Para ello, se ensayan probetas desnudas y recubiertas con distintos tipos de pintura, así como coloreados en masa. Se obtienen valores experimentales de la difusividad o permeabilidad al vapor o su inverso la resistividad al vapor de agua.Los datos obtenidos son muy útiles para valorar el fenómeno del intercambio de humedad entre el yeso y el ambiente, tanto durante el proceso de su secado inicial, como en el transcurso de su vida. Así como para disponer soluciones adecuadas para la evacuación del vapor de agua a través de los cerramientos, para utilizar la capacidad de regulación de la humedad, que proporciona el entramado poroso de los productos de yeso, o para impedir el paso del vapor de agua y evitar condensaciones.Como resumen de la investigación, se

Response of water vapour D-excess to land–atmosphere interactions in a semi-arid environment

KAUST Repository

Parkes, Stephen; McCabe, Matthew; Griffiths, Alan D.; Wang, Lixin; Chambers, Scott; Ershadi, Ali; Williams, Alastair G.; Strauss, Josiah; Element, Adrian

2017-01-01

The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour (d =δH-8× δO) can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (d). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (d) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime d values. The low d observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime d and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime d variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of d values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate d can generally be expected to show large spatial and temporal variability and to depend on the soil moisture state. For long periods between rain events, common in semi-arid environments, ET would be expected to impose negative forcing on the surface d. Spatial and temporal variability of D-excess in ET fluxes therefore needs to be considered when using d to study

Response of water vapour D-excess to land–atmosphere interactions in a semi-arid environment

KAUST Repository

Parkes, Stephen

2017-01-27

The stable isotopic composition of water vapour provides information about moisture sources and processes difficult to obtain with traditional measurement techniques. Recently, it has been proposed that the D-excess of water vapour (d =δH-8× δO) can provide a diagnostic tracer of continental moisture recycling. However, D-excess exhibits a diurnal cycle that has been observed across a variety of ecosystems and may be influenced by a range of processes beyond regional-scale moisture recycling, including local evaporation (ET) fluxes. There is a lack of measurements of D-excess in evaporation (ET) fluxes, which has made it difficult to assess how ET fluxes modify the Dexcess in water vapour (d). With this in mind, we employed a chamber-based approach to directly measure D-excess in ET (d) fluxes. We show that ET fluxes imposed a negative forcing on the ambient vapour and could not explain the higher daytime d values. The low d observed here was sourced from a soil water pool that had undergone an extended drying period, leading to low D-excess in the soil moisture pool. A strong correlation between daytime d and locally measured relative humidity was consistent with an oceanic moisture source, suggesting that remote hydrological processes were the major contributor to daytime d variability. During the early evening, ET fluxes into a shallow nocturnal inversion layer caused a lowering of d values near the surface. In addition, transient mixing of vapour with a higher D-excess from above the nocturnal inversion modified these values, causing large variability during the night. These results indicate d can generally be expected to show large spatial and temporal variability and to depend on the soil moisture state. For long periods between rain events, common in semi-arid environments, ET would be expected to impose negative forcing on the surface d. Spatial and temporal variability of D-excess in ET fluxes therefore needs to be considered when using d to study

Asphaltene precipitation and its effects on the vapour extraction (VAPEX) heavy oil recovery process

Energy Technology Data Exchange (ETDEWEB)

Luo, P.; Wang, X.; Gu, Y. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Regina Univ., SK (Canada). Petroleum Technology Research Centre; Zhang, H. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Core Laboratories Canada Ltd., Calgary, AB (Canada); Moghadam, L. [Fekete Associates Inc., Calgary, AB (Canada)

2008-10-15

One of the most important physical phenomena during the solvent vapour extraction (VAPEX) of heavy oil recovery is asphaltene precipitation. After the asphaltene precipitation occurs, the produced heavy oil is deasphalted in-situ, resulting in a lower viscosity and better quality. However, precipitated asphaltenes may plug some small pores of the reservoir formation, thus reducing its permeability. This paper examined the effects of three operating factors on the asphaltene precipitation during the VAPEX process, notably solvent type; operating pressure; and sand-pack permeability. Eight VAPEX tests were conducted to recover two different Lloydminster heavy oil samples from a rectangular sand-packed physical model with a butane mixture and propane as the respective solvents. The accumulative heavy oil and solvent production from the physical model were measured in the entire VAPEX process. The paper described the materials, experimental set-up, and experimental preparation. The VAPEX test was also explained. Results were presented for sand consolidation; solvent effect; pressure effect; and permeability effect. It was concluded that when the extracting solvent is in a liquid-gas state, asphaltene precipitation occurs and leads to in-situ deasphalting. 15 refs., 3 tabs., 6 figs.

Claims in vapour device (e-cigarette) regulation: A Narrative Policy Framework analysis.

Science.gov (United States)

O'Leary, Renée; Borland, Ron; Stockwell, Tim; MacDonald, Marjorie

2017-06-01

The electronic cigarette or e-cigarette (vapour device) is a consumer product undergoing rapid growth, and governments have been adopting regulations on the sale of the devices and their nicotine liquids. Competing claims about vapour devices have ignited a contentious debate in the public health community. What claims have been taken up in the state arena, and how have they possibly influenced regulatory outcomes? This study utilized Narrative Policy Framework to analyze the claims made about vapour devices in legislation recommendation reports from Queensland Australia, Canada, and the European Union, and the 2016 deeming rule legislation from the United States, and examined the claims and the regulatory outcomes in these jurisdictions. The vast majority of claims in the policy documents represented vapour devices as a threat: an unsafe product harming the health of vapour device users, a gateway product promoting youth tobacco uptake, and a quasi-tobacco product impeding tobacco control. The opportunity for vapour devices to promote cessation or reduce exposure to toxins was very rarely presented, and these positive claims were not discussed at all in two of the four documents studied. The dominant claims of vapour devices as a public health threat have supported regulations that have limited their potential as a harm reduction strategy. Future policy debates should evaluate the opportunities for vapour devices to decrease the health and social burdens of the tobacco epidemic. Copyright © 2017 Elsevier B.V. All rights reserved.

Retrieving mesospheric water vapour from observations of volume scattering radiances

Directory of Open Access Journals (Sweden)

P. Vergados

2009-02-01

Full Text Available This study examines the possibility for a theoretical approach in the estimation of water vapour mixing ratios in the vicinity of polar mesospheric clouds (PMC using satellite observations of Volume Scattering Radiances (VSR obtained at the wavelength of 553 nm. The PMC scattering properties perturb the underlying molecular Rayleigh scattered solar radiance of the background atmosphere. As a result, the presence of PMC leads to an enhancement in the observed VSR at the altitude of the layer; the PMC VSRs are superimposed on the exponentially decreasing with height Rayleigh VSR, of the PMC-free atmosphere. The ratio between the observed and the Rayleigh VSR of the background atmosphere is used to simulate the environment in which the cloud layer is formed. In addition, a microphysical model of ice particle formation is employed to predict the PMC VSRs. The initial water vapour profile is perturbed until the modelled VSRs match the observed, at which point the corresponding temperature and water vapour profiles can be considered as a first approximation of those describing the atmosphere at the time of the observations. The role of temperature and water vapour in the cloud formation is examined by a number of sensitivity tests suggesting that the water vapour plays a dominant role in the cloud formation in agreement with experimental results. The estimated water vapour profiles are compared with independent observations to examine the model capability in the context of this study. The results obtained are in a good agreement at the peak of the PMC layer although the radiance rapidly decreases with height below the peak. This simplified scenario indicates that the technique employed can give a first approximation estimate of the water vapour mixing ratio, giving rise to the VSR observed in the presence of PMC.

Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

Energy Technology Data Exchange (ETDEWEB)

Capan, I., E-mail: inci.capan@gmail.com [Balikesir University, Faculty of Art and Sciences, Department of Physics, Cagis Campus, 10145 Balikesir (Turkey); Tarimci, C., E-mail: Celik.Tarimci@eng.ankara.edu.tr [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Ankara (Turkey); Erdogan, M., E-mail: merdogan@balikesir.edu.tr [Balikesir University, Faculty of Art and Sciences, Department of Physics, Cagis Campus, 10145 Balikesir (Turkey); Hassan, A.K., E-mail: A.Hassan@shu.ac.uk [Materials and Engineering Research Institute, Sheffield Hallam University, Sheaf Building, Pond Street, Sheffield S1 1WB (United Kingdom)

2009-05-05

In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV-visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6-8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

Characterisation and vapour sensing properties of spin coated thin films of anthracene labelled PMMA polymer

International Nuclear Information System (INIS)

Capan, I.; Tarimci, C.; Erdogan, M.; Hassan, A.K.

2009-01-01

In the present article thin films of poly (methyl methacrylate) (PMMA) polymer labelled with anthracene (Ant-PMMA) prepared by spin coating are characterised by UV-visible spectroscopy, surface plasmon resonance (SPR), spectroscopic ellipsometry (SE) and Atomic Force Microscopy (AFM) and their organic vapour sensing properties are investigated. Ant-PMMA films' thickness are determined by performing theoretical fitting to experimental data measured using SPR and SE. Results obtained show that the spin-cast films are of good uniformity with an average thickness of 6-8 nm. Organic vapour sensing properties are studied using SPR technique during exposures to different volatile organic compounds (VOCs). Ant-PMMA films' response to the selected VOCs has been examined in terms of solubility parameters and molar volumes of the solvents, and the films were found to be largely sensitive to benzene vapour compared to other studied analytes.

In situ growth rate measurements during plasma-enhanced chemical vapour deposition of vertically aligned multiwall carbon nanotube films

International Nuclear Information System (INIS)

Joensson, M; Nerushev, O A; Campbell, E E B

2007-01-01

In situ laser reflectivity measurements are used to monitor the growth of multiwalled carbon nanotube (MWCNT) films grown by DC plasma-enhanced chemical vapour deposition (PECVD) from an iron catalyst film deposited on a silicon wafer. In contrast to thermal CVD growth, there is no initial increase in the growth rate; instead, the initial growth rate is high (as much as 10 μm min -1 ) and then drops off rapidly to reach a steady level (2 μm min -1 ) for times beyond 1 min. We show that a limiting factor for growing thick films of multiwalled nanotubes (MWNTs) using PECVD can be the formation of an amorphous carbon layer at the top of the growing nanotubes. In situ reflectivity measurements provide a convenient technique for detecting the onset of the growth of this layer

Evaporation of R134a in a horizontal herringbone microfin tube: heat transfer and pressure drop

Energy Technology Data Exchange (ETDEWEB)

Wellsandt, S; Vamling, L [Chalmers University of Technology, Gothenburg (Sweden). Department of Chemical Engineering and Environmental Science, Heat and Power Technology

2005-09-01

An experimental investigation of in-tube evaporation of R134a has been carried out for a 4 m long herringbone microfin tube with an outer diameter of 9.53 mm. Measured local heat transfer coefficients and pressure losses are reported for evaporation temperatures between -0.7 and 10.1 {sup o}C and mass flow rates between 162 and 366 kg m{sup -2} s{sup -1}. Results from this work are compared to experimental results from literature as well as predicted values from some available helical microfin correlations. Differences in heat transfer mechanisms between helical and herringbone microfin tubes are discussed, as heat transfer coefficients in the investigated herringbone tube tend to peak at lower vapour qualities compared to helical microfins. Correlations developed for helical microfin tubes generally predict experimental values within {+-}30% for vapour qualities below 50%. However, at higher qualities none of the correlations are able to reflect the early peak of heat transfer coefficients. Predicted pressure gradients reproduce measured values in general within {+-}20%. (author)

Modelling of blowdown of steam in the pressurized PPOOLEX facility

Energy Technology Data Exchange (ETDEWEB)

Paettikangas, T.; Niemi, J.; Timperi, A. (VTT Technical Research Centre of Finland (Finland))

2009-12-15

PPOOLEX experiment WLL-04-02 on condensation of vapour is studied with CFD simulations. Wall condensation model has been adapted to an Euler-Euler multiphase model of the Fluent CFD code for this purpose. In addition, a simple direct-contact condensation model has also been included in the code. The main focus of the CFD modelling work was on modelling condensation in the drywell. The amount of condensation found in the CFD calculation was in fair agreement with the experiment. The present simulation was so short that the gas flowing into the wetwell contained significant amount of air. The mole fraction of vapour at the outlet of the vent pipe had the maximum value of about 0.3. Therefore, the noncondensable gas strongly affected the direct-contact condensation in the water pool. Much longer simulations are needed in order to study jugging and condensation oscillations. FSI calculations of the experiments were performed by using the Star-CD, ABAQUS and MpCCI codes. An approximate method that makes possible numerically stable FSI calculations for the experimental facilities was used. The method is based on linear perturbation method which necessitates small structural deformations. The calculations showed that FSI has to be taken into account for the POOLEX facility which has relatively light structures. A way for determining the pressure source for the acoustic model from pressure measured at the pool bottom was also examined. Separation of the pressure component due to wall motion from the blowdown load was attempted by conducting a Fourier analysis on the measured displacement signal. The study showed that in practise sufficiently accurate acceleration signal cannot be obtained this way because the transformed signal gets easily out of phase. A measurement system was proposed which could be used for determining the pressure fluctuations. (author)

Modelling of blowdown of steam in the pressurized PPOOLEX facility

International Nuclear Information System (INIS)

Paettikangas, T.; Niemi, J.; Timperi, A.

2009-12-01

PPOOLEX experiment WLL-04-02 on condensation of vapour is studied with CFD simulations. Wall condensation model has been adapted to an Euler-Euler multiphase model of the Fluent CFD code for this purpose. In addition, a simple direct-contact condensation model has also been included in the code. The main focus of the CFD modelling work was on modelling condensation in the drywell. The amount of condensation found in the CFD calculation was in fair agreement with the experiment. The present simulation was so short that the gas flowing into the wetwell contained significant amount of air. The mole fraction of vapour at the outlet of the vent pipe had the maximum value of about 0.3. Therefore, the noncondensable gas strongly affected the direct-contact condensation in the water pool. Much longer simulations are needed in order to study jugging and condensation oscillations. FSI calculations of the experiments were performed by using the Star-CD, ABAQUS and MpCCI codes. An approximate method that makes possible numerically stable FSI calculations for the experimental facilities was used. The method is based on linear perturbation method which necessitates small structural deformations. The calculations showed that FSI has to be taken into account for the POOLEX facility which has relatively light structures. A way for determining the pressure source for the acoustic model from pressure measured at the pool bottom was also examined. Separation of the pressure component due to wall motion from the blowdown load was attempted by conducting a Fourier analysis on the measured displacement signal. The study showed that in practise sufficiently accurate acceleration signal cannot be obtained this way because the transformed signal gets easily out of phase. A measurement system was proposed which could be used for determining the pressure fluctuations. (author)

On-line pressure measurement using scanning systems

International Nuclear Information System (INIS)

Morss, A.G.; Watson, A.P.

1978-08-01

Data collection methods can be improved significantly by using pressure scanning systems in conjunction with transducers for the measurement of pressure distribution in fluid flow rigs. However, the response of pressure transducers to the slight random pressure fluctuations that occur in practice can cause some measurement problems, especially for accurate work. The nature of these pressure fluctuations is examined and suitable analysis techniques are recommended. Results obtained using these techniques are presented. It is concluded that by using the correct techniques pressure transducer systems can be used to measure pressure distributions accurately and are sufficiently sensitive to measure very small systematic effects with great precision. (author)

Chemical vapour deposition at atmospheric pressure of graphene on molybdenum foil: Effect of annealing time on characteristics and corrosion stability of graphene coatings

International Nuclear Information System (INIS)

Naghdi, Samira; Jevremović, Ivana; Mišković-Stanković, Vesna; Rhee, Kyong Yop

2016-01-01

Highlights: • Atmospheric pressure chemical vapor deposition of graphene on molybdenum foils. • Quality and domain size of graphene layers increased with longer annealing times. • The number of graphene layers decreased with longer annealing times. • Graphene coatings on molybdenum foils exhibited corrosion inhibitive properties. - Abstract: In this work, the effect of pre-annealing of Mo substrate on the quality of graphene layers grown by chemical vapour deposition was investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Moreover, different electrochemical techniques were employed to investigate the corrosion stability of the graphene coated Mo in 0.1 M NaCl. Longer annealing time resulted in less defective graphene coatings with fewer layers. Graphene coating on the annealed Mo provided better protection against corrosion during the initial exposure times, while after prolonged exposure times, both graphene coatings on annealed and non-annealed Mo exhibited nearly the same corrosion inhibitive properties.

Collisional effects on metastable atom population in vapour generated by electron beam heating

International Nuclear Information System (INIS)

Dikshit, B; Majumder, A; Bhatia, M S; Mago, V K

2008-01-01

The metastable atom population distribution in a free expanding uranium vapour generated by electron beam (e-beam) heating is expected to depart from its original value near the source due to atom-atom collisions and interaction with electrons of the e-beam generated plasma co-expanding with the vapour. To investigate the dynamics of the electron-atom and atom-atom interactions at different e-beam powers (or source temperatures), probing of the atomic population in ground (0 cm -1 ) and 620 cm -1 metastable states of uranium was carried out by the absorption technique using a hollow cathode discharge lamp. The excitation temperature of vapour at a distance ∼30 cm from the source was calculated on the basis of the measured ratio of populations in 620 to 0 cm -1 states and it was found to be much lower than both the source temperature and estimated translational temperature of the vapour that is cooled by adiabatic free expansion. This indicated relaxation of the metastable atoms by collisions with low energy plasma electrons was so significant that it brings the excitation temperature below the translational temperature of the vapour. So, with increase in e-beam power and hence atom density, frequent atom-atom collisions are expected to establish equilibrium between the excitation and translational temperatures, resulting in an increase in the excitation temperature (i.e. heating of vapour). This has been confirmed by analysing the experimentally observed growth pattern of the curve for excitation temperature with e-beam power. From the observed excitation temperature at low e-beam power when atom-atom collisions can be neglected, the total de-excitation cross section for relaxation of the 620 cm -1 state by interaction with low energy electrons was estimated and was found to be ∼10 -14 cm 2 . Finally using this value of cross section, the extent of excitational cooling and heating by electron-atom and atom-atom collisions are described at higher e-beam powers

Modification of Peng Robinson EOS for modelling (vapour + liquid) equilibria with electrolyte solutions

International Nuclear Information System (INIS)

Baseri, Hadi; Lotfollahi, Mohammad Nader

2011-01-01

Highlights: → Extended PR-EOS was presented for VLE of H 2 O/Salt/CO 2 systems at high pressure. → The proposed EPR-EOS is based upon contributions to the Helmholtz energy. → Born, Margules, and Debye-Huckel or mean spherical approximation terms were used. → Two different mixing rules Panagiotopoulos and Reid and Kwak and Mansoori (KM) were used. → A combination of KM mixing rule with DH term results more accurate VLE results. - Abstract: A modification of the extended Peng-Robinson equation of state (PR-EOS) is presented to describe the (vapour + liquid) equilibria of systems containing water and salts. The modification employs three additional terms including a Born term, a Margules term and two terms separately used for estimation of the long-range electrostatic interactions (the Debye-Huckel (DH) or the mean spherical approximation (MSA) terms). Effects of two mixing rules, first, the Panagiotopoulos and Reid mixing rule (PR) and, second, the Kwak and Mansoori mixing rule (KM), on the final values of VLE calculations are also investigated. The results show that the KM mixing rule is more appropriate than the PR mixing rule. The proposed equation of state is used to calculate the (vapour + liquid) equilibrium (VLE) of the systems containing (water + sodium sulphate + carbon dioxide) and (water + sodium chloride + carbon dioxide) at high pressure. The comparison of calculated results with the experimental data shows that a combination of KM mixing rule with the DH term results a more accurate VLE values.

Fission product vapour - aerosol interactions in the containment: simulant fuel studies

International Nuclear Information System (INIS)

Beard, A.M.; Benson, C.G.; Bowsher, B.R.

1988-12-01

Experiments have been conducted in the Falcon facility to study the interaction of fission product vapours released from simulant fuel samples with control rod aerosols. The aerosols generated from both the control rod and fuel sample were chemically distinct and had different deposition characteristics. Extensive interaction was observed between the fission product vapours and the control rod aerosol. The two dominant mechanisms were condensation of the vapours onto the aerosol, and chemical reactions between the two components; sorption phenomena were believed to be only of secondary importance. The interaction of fission product vapours and reactor materials aerosols could have a major impact on the transport characteristics of the radioactive emission from a degrading core. (author)

Sensing response of copper phthalocyanine salt dispersed glass with organic vapours

Energy Technology Data Exchange (ETDEWEB)

Ridhi, R.; Sachdeva, Sheenam; Saini, G. S. S.; Tripathi, S. K., E-mail: surya@pu.ac.in [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh-160 014 (INDIA) Fax: +91-172-2783336; Tel.:+91-172-2544362 (India)

2016-05-06

Copper Phthalocyanine and other Metal Phthalocyanines are very flexible and tuned easily to modify their structural, spectroscopic, optical and electrical properties by either functionalizing them with various substituent groups or by replacing or adding a ligand to the central metal atom in the phthalocyanine ring and accordingly can be made sensitive and selective to various organic species or gaseous vapours. In the present work, we have dispersed Copper Phthalocyanine Salt (CuPcS) in sol-gel glass form using chemical route sol-gel method and studied its sensing mechanism with organic vapours like methanol and benzene and found that current increases onto their exposure with vapours. A variation in the activation energies was also observed with exposure of vapours.

Hybrid chemical vapour and nanoceramic aerosol assisted deposition for multifunctional nanocomposite thin films

Energy Technology Data Exchange (ETDEWEB)

Warwick, Michael E.A.; Dunnill, Charles W.; Goodall, Josie; Darr, Jawwad A.; Binions, Russell, E-mail: uccarbi@ucl.ac.uk

2011-07-01

Hybrid atmospheric pressure chemical vapour and aerosol assisted deposition via the reaction of vanadium acetylacetonate and a suspension of preformed titanium dioxide or cerium dioxide nanoparticles, led to the production of vanadium dioxide nanocomposite thin films on glass substrates. The preformed nanoparticle oxides used for the aerosol were synthesised using a continuous hydrothermal flow synthesis route involving the rapid reaction of a metal salt solution with a flow of supercritical water in a flow reactor. Multifunctional nanocomposite thin films from the hybrid deposition process were characterised using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The functional properties of the films were evaluated using variable temperature optical measurements to assess thermochromic behaviour and methylene blue photodecolourisation experiments to assess photocatalytic activity. The tests show that the films are multifunctional in that they are thermochromic (having a large change in infra-red reflectivity upon exceeding the thermochromic transition temperature) and have significant photocatalytic activity under irradiation with 254 nm light.

Unsteady pressures on a blunt trailing edge measured with an embedded pressure scanner

Science.gov (United States)

Naughton, Jonathan; Nikoueeyan, Pourya; Hind, Michael; Strike, John; Dahland, Matz; Keeter, Steven

2017-11-01

Development of direct-mount pressure scanners can decrease the pneumatic tubing length required to connect the measurement ports to the scanner manifold resulting in improved dynamic range for unsteady pressure measurements. In this work, the performance of a direct-mount pressure scanner for time-resolved pressure measurement is demonstrated in a well-established flow; the pressure fluctuations near the base of flat plate is considered. The additive manufactured model is instrumented with a pressure scanner and flush-mounted high-speed pressure transducers. The configuration of the ports on the model allows for side-by-side comparison of the pressures measured via embedded pneumatic tubing routed to a pressure scanner with that measured by high-speed transducers. Prior to testing, the dynamic response of each embedded pressure port is dynamically calibrated via an in-situ calibration technique. Pressure data is then acquired for fixed angle-of-attack and different dynamic pitching conditions. The dynamic range of the measurements acquired via direct-mount scanner will be compared to those acquired by the high speed transducers for both static and dynamic pitching configurations. The uncertainties associated with Weiner deconvolution are also quantified for the measurements.

Measurement of intraocular pressure with pressure phosphene tonometry in children.

Science.gov (United States)

Fan, Dorothy S P; Chiu, Thomas Y H; Congdon, Nathan; Chan, Jeffrey C W; Cheung, Eva Y Y; Lam, Dennis S C

2011-01-01

To study the accuracy and acceptability of intraocular pressure (IOP) measurement by the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer in children. Fifty children (5 to 14 years old) participated in this prospective comparative study. IOP was measured with the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer by three different examiners who were masked to the results. The children were also asked to grade the degree of discomfort from 0 to 5 (0 = no discomfort; 5 = most discomfort). The mean IOPs measured by the Goldmann tonometer, pressure phosphene tonometer, and non-contact tonometer were 15.9 mm Hg (standard deviation [SD]: = 5.5 mm Hg; range: 10 to 36 mm Hg), 16.0 mm Hg (SD: 2.9 mm Hg; range: 12 to 25 mm Hg), and 15.7 mm Hg (SD = 5.1 mm Hg; range: 8 to 32 mm Hg), respectively (P = .722). The mean difference between pressure phosphene tonometer and Goldmann tonometer readings was 2.9 mm Hg and that between non-contact tonometer and Goldmann tonometer readings was 2.1 mm Hg. The 95% confidence interval of the mean difference between pressure phosphene tonometer and Goldmann tonometer readings was -1.07 and 1.19, and that between non-contact tonometer and Goldmann tonometer readings was -1.07 and 0.53. The mean discomfort ratings for the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer were 0.6, 2.0, and 2.3, respectively (P tonometer was less accurate than the non-contact tonometer compared with Goldmann tonometer, it gave a reasonably close estimate and had a high specificity of raised IOP. In addition, measurement by the pressure phosphene tonometer is most acceptable to children. The pressure phosphene tonometer can be considered as an alternative method of IOP measurement in children. Copyright 2011, SLACK Incorporated.

Experimental study of the thermal conductivity coefficients of Cesium and Mercury vapours and inert gases

International Nuclear Information System (INIS)

Zarkova, L.P.

1976-01-01

A general-purpose experimental setup is made to measure thermal conductivity coefficients lambda of inert gases and metal vapours in the range 1000-2500 K by means of the differential method. The setup can also be used to measure lambda of plasmas and reacting gases as well as the dependence of lambda on magnetic fields. A simple and reliable procedure to determine the filament temperature using values of the measured current and wire diameter is suggested. The influence of different factors such as the temperature jump at the boundary gas-filament, convective heat transfer, thermal expansion, excentricity and cold ends of filament on the measured values of the thermal conductivity is considered in details. A formula is deduced to calculate the temperature jump correction taking into account the dependence of the mean free path on the temperature. Expressions are also given to calculate the corrections for thermal expansion, eccentricity and cold ends of the filament. Thermal conductivity coefficients of inert gases are measured to check the method: Ne in the range 1100-2200 K, Ar in the range 1000-2200 K, Kr in the range 1300-2300 K and Xe in the range 1100-2200 K. The data for Ne and Xe in the range 1500 to 2200 K and for Kr at T=2000-2300 K are original. The thermal conductivity coefficient of monoatomic mercury vapour is measured in the range 1000-2300 K with 3% error. The thermal conductivity coefficient of monoatomic cesium vapour is also measured in the range 1000-1600 K with 4% error. (I.P.)

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

International Nuclear Information System (INIS)

Gnanakumari, P.; Venkatesu, P.; Hsieh, C.-T.; Rao, M.V. Prabhakara; Lee, M.-J.; Lin, Ho-mu

2009-01-01

The (vapour + liquid) equilibrium (VLE) and boiling temperature measurements have been determined at 95.3 kPa as a function of composition for the binary liquid mixtures of N-methyl-2-pyrrolidone (NMP) with branched alcohols using a Swietoslawski-ebulliometer. The branched alcohols include 2-propanol, 2-butanol, 2-methyl-l- propanol, 2-methyl-2-propanol, and 3-methyl-l-butanol. The experimental temperature-composition (T-x) results were used to estimate Wilson parameters and then used to calculate the equilibrium vapour compositions and the excess Gibbs free energy at T = 298.15 K. The experimental temperature-composition (T, x) results were correlated with the Wilson, the NRTL and the UNIQUAC models. The experimental results are interpreted in terms of intermolecular interactions between constituent molecules

Signal quality measures for unsupervised blood pressure measurement

International Nuclear Information System (INIS)

Abdul Sukor, J; Redmond, S J; Lovell, N H; Chan, G S H

2012-01-01

Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure

Phosphorus doping and deposition pressure effects on optical and electrical properties of polysilicon

International Nuclear Information System (INIS)

Zaghdoudi, M.; Abdelkrim, M.M.; Fathallah, M.; Mohammed-Brahim, T.; Rogel, R.

2006-01-01

The optical and electrical properties of amorphously deposited and then post-crystallized silicon films are studied as a function of the deposition pressure and the phosphorus doping. Amorphous silicon films are deposited in a high pressure regime by SAPCVD (Sub-Atmospheric Pressure Chemical Vapour Deposition) to study the effect of the deposition pressure. They are also deposited in a low pressure regime by LPCVD (Low Pressure Chemical Vapour Deposition) to study the effect of a low phosphorus doping. Both types of amorphous films are then crystallized in the solid phase at 600 deg. C. Using different optical and electrical characterization techniques, the beneficial effect of a high pressure as well as of a weak phosphorus doping on the decrease of the defect density is highlighted. These results give some ways to improve the quality of polysilicon enough to be used in photovoltaic or in thin film electronic devices

Modelling water vapour permeability through atomic layer deposition coated photovoltaic barrier defects

Energy Technology Data Exchange (ETDEWEB)

Elrawemi, Mohamed, E-mail: Mohamed.elrawemi@hud.ac.uk [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Blunt, Liam; Fleming, Leigh [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom); Bird, David, E-mail: David.Bird@uk-cpi.com [Centre for Process Innovation Limited, Sedgefield, County Durham (United Kingdom); Robbins, David [Centre for Process Innovation Limited, Sedgefield, County Durham (United Kingdom); Sweeney, Francis [EPSRC Centre for Innovative Manufacturing in Advanced Metrology, School of Computing and Engineering, University of Huddersfield, Huddersfield (United Kingdom)

2014-11-03

Transparent barrier films such as Al{sub 2}O{sub 3} used for prevention of oxygen and/or water vapour permeation are the subject of increasing research interest when used for the encapsulation of flexible photovoltaic modules. However, the existence of micro-scale defects in the barrier surface topography has been shown to have the potential to facilitate water vapour ingress, thereby reducing cell efficiency and causing internal electrical shorts. Previous work has shown that small defects (≤ 3 μm lateral dimension) were less significant in determining water vapour ingress. In contrast, larger defects (≥ 3 μm lateral dimension) seem to be more detrimental to the barrier functionality. Experimental results based on surface topography segmentation analysis and a model presented in this paper will be used to test the hypothesis that the major contributing defects to water vapour transmission rate are small numbers of large defects. The model highlighted in this study has the potential to be used for gaining a better understanding of photovoltaic module efficiency and performance. - Highlights: • A model of water vapour permeation through barrier defects is presented. • The effect of the defects on the water vapour permeability is investigated. • Defect density correlates with water vapour permeability. • Large defects may dominate the permeation properties of the barrier film.

Blood Pressure Measurement: Clinic, Home, Ambulatory, and Beyond

Science.gov (United States)

Drawz, Paul E.; Abdalla, Mohamed; Rahman, Mahboob

2014-01-01

Blood pressure has traditionally been measured in the clinic setting using the auscultory method and a mercury sphygmomanometer. Technological advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24 hour ambulatory blood pressures have improved our ability to evaluate risk for target organ damage and hypertension related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables the measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are two of the newer methods for assessing blood pressure and hypertension related target organ damage. PMID:22521624

Characterization of aqueous interactions of copper-doped phosphate-based glasses by vapour sorption.

Science.gov (United States)

Stähli, Christoph; Shah Mohammadi, Maziar; Waters, Kristian E; Nazhat, Showan N

2014-07-01

Owing to their adjustable dissolution properties, phosphate-based glasses (PGs) are promising materials for the controlled release of bioinorganics, such as copper ions. This study describes a vapour sorption method that allowed for the investigation of the kinetics and mechanisms of aqueous interactions of PGs of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0, 1, 5 and 10mol.%). Initial characterization was performed using (31)P magic angle spinning nuclear magnetic resonance and attenuated total reflectance-Fourier transform infrared spectroscopy. Increasing CuO content resulted in chemical shifts of the predominant Q(2) NMR peak and of the (POP)as and (PO(-)) Fourier transform infrared absorptions, owing to the higher strength of the POCu bond compared to PONa. Vapour sorption and desorption were gravimetrically measured in PG powders exposed to variable relative humidity (RH). Sorption was negligible below 70% RH and increased exponentially with RH from 70 to 90%, where it exhibited a negative correlation with CuO content. Vapour sorption in 0% and 1% CuO glasses resulted in phosphate chain hydration and hydrolysis, as evidenced by protonated Q(0)(1H) and Q(1)(1H) species. Dissolution rates in deionized water showed a linear correlation (R(2)>0.99) with vapour sorption. Furthermore, cation release rates could be predicted based on dissolution rates and PG composition. The release of orthophosphate and short polyphosphate species corroborates the action of hydrolysis and was correlated with pH changes. In conclusion, the agreement between vapour sorption and routine characterization techniques in water demonstrates the potential of this method for the study of PG aqueous reactions. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Micro packaged MEMS pressure sensor for intracranial pressure measurement

International Nuclear Information System (INIS)

Liu Xiong; Yao Yan; Ma Jiahao; Zhang Zhaohua; Zhang Yanhang; Wang Qian; Ren Tianling

2015-01-01

This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm 2 . It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm 2 . In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm 2 . Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10 −2 mV/kPa. (paper)

[Invasive arterial blood pressure measurement using an aneroid pressure system in cattle].

Science.gov (United States)

Mosing, M; Franz, S; Iff, I; Schwendenwein, I

2009-06-01

The aim of this study was to compare the results of invasive arterial blood pressure measurement using an electronic pressure transducer (EPT) or an aneroid pressure system (APS) in cattle. A catheter was placed in the auricular artery of 11 adult cattle and connected to a pressure transducer via pressure line. The aneroid system was connected to the same catheter using a three-way stop-cock in the pressure line. On five occasions three consecutive measurements were performed with the APS. The mean blood pressure values of the EPT were recorded before each individual measurement. Values from each device were compared using Passing and Bablok regression of agreement and a Bland and Altman difference plot. One hundred and forty-seven paired measurements were analysed. The average bias between the two methods (EPT vs. APS) was -1.6 mmHg (95 % confidence interval [CI]: -3.0 to -0.2 mmHg). The coefficient of correlation was 1.0084. The aneroid system showed an almost perfect agreement with the EPT. This study shows that it can be used in a clinical setting as well as under field conditions to measure arterial blood pressure in cattle.

Modelling (vapour + liquid) and (vapour + liquid + liquid) equilibria of {water (H2O) + methanol (MeOH) + dimethyl ether (DME) + carbon dioxide (CO2)} quaternary system using the Peng-Robinson EoS with Wong-Sandler mixing rule

International Nuclear Information System (INIS)

Ye Kongmeng; Freund, Hannsjoerg; Sundmacher, Kai

2011-01-01

Highlights: → Phase behaviour modelling of H 2 O-MeOH-DME under pressurized CO 2 (anti-solvent) using PRWS. → PRWS-UNIFAC-PSRK has better performance than PRWS-UNIFAC-Lby in general. → Reliable to extend the VLE and VLLE phase behaviour from binary to multicomponent systems. → Successful prediction of the VLE and VLLE of binary, ternary, and quaternary systems. → Potential to apply the model for designing new DME separation process. - Abstract: The (vapour + liquid) equilibria (VLE) and (vapour + liquid + liquid) equilibria (VLLE) binary data from literature were correlated using the Peng-Robinson (PR) equation of state (EoS) with the Wong-Sandler mixing rule (WS). Two group contribution activity models were used in the PRWS: UNIFAC-PSRK and UNIFAC-Lby. The systems were successfully extrapolated from the binary systems to ternary and quaternary systems. Results indicate that the PRWS-UNIFAC-PSRK generally displays a better performance than the PRWS-UNIFAC-Lby.

Commentary on differential-pressure measurements at high reference pressures

International Nuclear Information System (INIS)

Hasbrouck, R.T.; Noyes, R.P.

1981-01-01

Some practical approaches to the difficult problems in calibrating and implementing differential-pressure measurements are discussed. The data presented were gathered several years ago in separate investigations. An attempt is made to compare the results of these investigations to the common mode concept as described by Peter K. Stein in his publication, The Measurement of Differential Quantities - Problems and Approaches. Although one of these investigations involed a 10,000- to 20,000-psi reference-pressure gas measured at an ambient temperature and the other a classic /sup Δ/P flow measurement of cryogenic temperature, the problems encountered were the same

Some thermodynamic properties of hydrogen chloride and deuterium chloride

Energy Technology Data Exchange (ETDEWEB)

Henderson, C; Lewis, D G; Prichard, P C; Staveley, L A.K.; Fonseca, I M.A.; Lobo, L Q

1986-01-01

The molar volume of HCl has been measured from 162 to 236 K, and of DCl from 160 to 218 K. Direct measurements of the vapour pressure of HCl have been made from 159 to 220 K, and of DCl from 158 to 188 K. In addition, the difference in the vapour pressure of the two isotopic forms has been measured from 159 to 226 K. At lower temperatures, the vapour pressure of HCl exceeds that of DCl but above 223.35 K that position is reversed. The vapour pressure of each substance has been fitted to a Wagner equation. These equations have been used in conjunction with the Clapeyron equation to calculate the molar enthalpies of vaporization. If r is the ratio of the vapour pressure of HCl to that of DCl, the values of r conform very closely to the equation T ln r = - A + C/T, where A and C are constants.

Measurement of fast transient pressures

International Nuclear Information System (INIS)

Procaccia, Henri

1978-01-01

The accuracy, reliability and sensitivity of a pressure transducers define its principal static characteristics. When the quantity measured varies with time, the measurement carries a dynamic error and a delay depending on the frequency of this variation. Hence, when fast pressure changes in a fluid have to be determined, different kinds of pressure transducers can be used depending on their inherent dynamic characteristics which must be compared with those of the transient phenomenon to be analysed. The text describes the pressure transducers generally employed in industry for analysing such phenomenon and gives two practical applications developed in the EDF: the first submits the measurements and results of pump cavitation tests carried out at the Vitry II EDF power station; the second deals with hammer blows particularly noticed in nuclear power stations and required the use of transducers of exceptionally high performance such as strain gauge transducers and piezoelectric transducers (response time within 1m sec.) [fr

The speed of sound in a gas–vapour bubbly liquid

Science.gov (United States)

Prosperetti, Andrea

2015-01-01

In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model. PMID:26442146

The speed of sound in a gas-vapour bubbly liquid.

Science.gov (United States)

Prosperetti, Andrea

2015-10-06

In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model.

Two-phase pressure drop and heat transfer of sodium at forced convection

International Nuclear Information System (INIS)

Grieb, G.

1989-04-01

Experiments with sodium for the two-phase pressure drop in vertical tubes with upward flow (internal diameters 6 and 9 mm) performed at the Joint Research Centre (JRC) of the European Communities in Ispra, Italy, and at the Nuclear Research Centre in Karlsruhe (KfK) were evaluated and analysed. Furthermore, experiments for the single-phase and two-phase heat transfer in the grid spaced twelve-rod bundle (p d /d =1.3, rod diameter 8 mm) with flow in axial direction performed at the JRC were evaluated and analysed. The pressure drop measurements were carried out at moderate to high mass flow rates (30 to 4500 kg/(m 2 s)) and at moderate pressures (50 to 300 kPa, density ratio ρ f /ρ g = 950 to 5400). The measurements for the single-phase heat transfer at high heat fluxes (0.16 to 1.6 MW/m 2 ) were carried out in the Reynolds number region (3100 2 s)) and at high heat fluxes (0.46 to 1.6 MW/m 2 ) within the temperature range from 870 to 970 0 C. For the subsequent calculation of the experiments relating to the two-phase pressure drop a computer program was developed, which is based on the so-called slip model. It requires a friction pressure loss correlation and a slip correlation. The tested correlations were not suitable for describing the experimental measurements. Accordingly, simplified equations of momentum were used to develop a new slip correlation for the case of annular flow together with the annular-mist flow, the most important two-phase flow regimes for sodium in the measurement range. After the inception of the entrainment - transition from the annular flow to the annular-mist flow - an even larger fraction of liquid enters the vapour core in the form of droplets, as the vapour quality increases. An equation was formulated for the slip in this region and adapted to the experiments via coefficients. (orig./GL) [de

Drivers of radial growth and carbon isotope discrimination of bur oak (Quercus macrocarpa Michx.) across continental gradients in precipitation, vapour pressure deficit and irradiance.

Science.gov (United States)

Voelker, Steven L; Meinzer, Frederick C; Lachenbruch, Barbara; Brooks, J Renée; Guyette, Richard P

2014-03-01

Tree-ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary environmental controls on ring-width indices (RWIs) and carbon stable isotope discrimination (Δ(13) C) in tree-ring cellulose. Variation in Δ(13) C and RWI was more strongly related to leaf-to-air vapour pressure deficit (VPD) at the centre and western edge of the range compared with the northern and wettest regions. Among regions, Δ(13) C of tree-ring cellulose was closely predicted by VPD and light responses of canopy-level Δ(13) C estimated using a model driven by eddy flux and meteorological measurements (R(2)  = 0.96, P = 0.003). RWI and Δ(13) C were positively correlated in the drier regions, while they were negatively correlated in the wettest region. The strength and direction of the correlations scaled with regional VPD or the ratio of precipitation to evapotranspiration. Therefore, the correlation strength between RWI and Δ(13) C may be used to infer past wetness or aridity from paleo wood by determining the degree to which carbon gain and growth have been more limited by moisture or light. © 2013 John Wiley & Sons Ltd.

Isothermal vapour-liquid equilibrium data for the binary systems of (CHF3 or C2F6) and n-heptane

International Nuclear Information System (INIS)

Williams-Wynn, Mark D.; Naidoo, Paramespri; Ramjugernath, Deresh

2016-01-01

Highlights: • Isothermal static-analytic and static-synthetic phase equilibrium measurements. • Binary VLE data for (CHF3 or C 2 F 6 ) + n-heptane. • Thermodynamic models were fitted to the experimental data. • Critical locus estimation for the systems. - Abstract: Isothermal vapour-liquid equilibrium (VLE) values for two binary systems; trifluoromethane and n-heptane at temperatures between T = (272.9 and 313.2) K, and hexafluoroethane and n-heptane at temperatures between T = (293.0 and 313.2) K were measured with a static-analytic apparatus. Bubble pressures at temperatures between T = (293.0 and 313.2) K, at several compositions, were also measured with a variable-volume static-synthetic apparatus. Vapour-liquid-liquid equilibrium (VLLE) was found to occur for certain isotherms for both of the systems. The PR EOS, with the Mathias-Copeman (MC) alpha function, combined with either the classical mixing rule or the Wong-Sandler (WS) mixing rule was used to correlate the experimental results. Either the NRTL or the UNIQUAC activity coefficient model was used within the WS mixing rule. The indirect extended scaling laws of Ungerer et al. were used to extrapolate critical loci from the experimental coexistence data, and the calculation procedure of Heidemann and Khalil was employed to calculate the mixture critical locus curves at temperatures close to the refrigerant critical temperatures. At lower temperatures on the mixture critical curve, gas-liquid critical points occurred, whereas, at higher temperatures, the critical points occurred along a liquid-liquid locus curve. The two systems were categorised according to the van Konynenburg and Scott classification.

The thermotidal exciting function for water vapour absorption of solar radiation

Directory of Open Access Journals (Sweden)

M. BONAFEDE

1976-06-01

Full Text Available The thermotidal exciting function J is considered, for
the absorption of solar radiation by water vapour, according to the model
derived by Siebert. The Mugge-Moller formula for water vapour absorption
is integrated numerically, using experimental data for the water vapour
concentration in the troposphere and the stratosphere. It appears that
Siebort's formula is a reasonable approximation at low tropospheric levels
but it dramatically overestimates the water vapour thermotidal heating
in the upper troposphere and in the stratosphere. It seems thus possible
that, if the correct vertical profile is employed for J , the amplitudes and
phases of the diurnal temperature oscillations and of the tidal wind speeds
may suffer significant changes from those previously calculated and possibly explain the three hours delay of the observed phases from the computed values.

Pancreas tumor interstitial pressure catheter measurement

Science.gov (United States)

Nieskoski, Michael D.; Gunn, Jason; Marra, Kayla; Trembly, B. Stuart; Pogue, Brian W.

2016-03-01

This paper highlights the methodology in measuring interstitial pressure in pancreatic adenocarcinoma tumors. A Millar Mikrotip pressure catheter (SPR-671) was used in this study and a system was built to amplify and filter the output signal for data collection. The Millar pressure catheter was calibrated prior to each experiment in a water column at 37°C, range of 0 to 60 inH2O (112 mmHg), resulting in a calibration factor of 33 mV / 1 inH2O. The interstitial pressures measured in two orthotopically grown pancreatic adenocarcinoma tumor were 57 mmHg and 48 mmHg, respectively. Verteporfin uptake into the pancreatic adenocarcinoma tumor was measured using a probe-based experimental dosimeter.

[Comparison of invasive blood pressure measurement in the aorta with indirect oscillometric blood pressure measurement at the wrist and forearm].

Science.gov (United States)

Saul, F; Aristidou, Y; Klaus, D; Wiemeyer, A; Lösse, B

1995-09-01

Indirectly measured blood pressure at the wrist or upper arm was compared with directly measured values in the aortic arch during routinely performed diagnostic cardiac catheterization in 100 patients (31-80 years, mean 59.3 years, 60% males). The noninvasive measurements were carried out by oscillometric devices, NAiS Blood Pressure Watch for measurements at the wrist, and Hestia OZ80 at the upper arm. Systolic blood pressure measured at the wrist was 4.3 +/- 14.1 mm Hg, and the diastolic value 6.0 +/- 8.9 mm Hg higher than when measured at the aortic arch; the difference was significant in both cases. Correlation coefficients were 0.85 for systolic and 0.71 for diastolic blood pressure. In 16% of the patients the systolic blood pressure at the wrist differed more than +/- 20 mm Hg. The diastolic blood pressure at the wrist measured more than +/- 20 mm Hg higher than in the aorta in 5% of the patients. At the upper arm mean systolic values were not different to the aorta. The diastolic pressure was 9.3 +/- 9.8 mm Hg higher in the aorta than at the upper arm. To verify the accuracy of values measured with the NAiS Blood Pressure Watch compared with the standard technique at the upper arm, sequential measurements were made at wrist and ipsilateral upper arm in the same group of 100 patients. The systolic blood pressure at the left wrist was 3.4 +/- 13.3 mm Hg higher and the diastolic pressure 3.8 +/- 9.5 mm Hg lower than at the upper arm. Only 53% of systolic values lay within a range of +/- 10 mm Hg. The correspondence between wrist and upper arm values was better for diastolic blood pressure, the values differing by less than +/- 10 mm Hg in two-thirds of patients. Self-measurement of arterial blood pressure with an oscillometric device at the wrist can be recommended only in individual cases with a difference of simultaneously measured values at the upper arm of less than +/- 10 mm Hg for systolic and diastolic blood pressures. The standard method for indirectly

Computational estimation of logarithm of octanol/air partition coefficients and subcooled vapour pressures for each of 75 chloronaphtalene congeners

Energy Technology Data Exchange (ETDEWEB)

Puzyn, T.; Falandysz, J.; Rostkowski, P.; Piliszek, S.; Wilczyniska, A. [Univ. of Gdansk (Poland)

2004-09-15

Polychlorinated naphthalenes (PCNs, CNs) are known persistent organic pollutants, contaminating natural ecosystems in effect of technical human activity. Toxic effects induced by individual congers of PCNs are reported elsewhere. Great risk of these chemical compounds is additionally connected with theirs excellent ability to be transported via atmosphere from a source to the remote regions on the Glob. Chloronaphthalene congeners had been found in Arctic regions at significant level in spite of the fact, that they had never been synthesized there, and also thermal processes like municipal waste incineration or domestic heating (other possible sources of PCNs in the environment) were not so intensive there. In 1996 F. Wania and D. Mackay have formulated some empirical rules, which have been very useful in estimation and modeling of environmental transport processes of persistent organic pollutants like PCNs. Two very important physico-chemical parameters in the theory of global distillation and cold condensation are: logarithm of n-octanol/air partition coefficient (log K{sub OA}) and logarithm of subcooled vapour pressure (log P{sub L}). Values of log K{sub OA} and log P{sub L} in standard procedures are determined by means of chromatographic methods. In order to reduce costs and number of experiments, we have proposed simple computational method of estimation log K{sub OA} and log P{sub L}.

Development of graphene nanoplatelet embedded polymer microcantilever for vapour phase explosive detection applications

International Nuclear Information System (INIS)

Ray, Prasenjit; Pandey, Swapnil; Ramgopal Rao, V.

2014-01-01

In this work, a graphene based strain sensor has been reported for explosive vapour detection applications by exploiting the piezoresistive property of graphene. Instead of silicon based cantilevers, a low cost polymeric micro-cantilever platform has been used to fabricate this strain sensor by embedding the graphene nanoplatelet layer inside the beam. The fabricated devices were characterized for their mechanical and electromechanical behaviour. This device shows a very high gauge factor which is around ∼144. Also the resonant frequency of these cantilevers is high enough such that the measurements are not affected by environmental noise. These devices have been used in this work for reliable detection of explosive vapours such as 2,4,6-Trinitrotoluene down to parts-per-billion concentrations in ambient conditions.

Fast Neutral Pressure Measurements in NSTX

International Nuclear Information System (INIS)

R. Raman; H.W. Kugel; T. Provost; R. Gernhardt; T.R. Jarboe; M.G. Bell

2002-01-01

Several fast neutral pressure gauges have been installed on NSTX [National Spherical Torus Experiment] to measure the vessel and divertor pressure during inductive and coaxial helicity injected (CHI) plasma operations. Modified, PDX [Poloidal Divertor Experiment]-type Penning gauges have been installed on the upper and lower divertors. Neutral pressure measurements during plasma operations from these and from two shielded fast Micro ion gauges at different toroidal locations on the vessel mid-plane are described. A new unshielded ion gauge, referred to as the In-vessel Neutral Pressure (INP) gauge is under development

Ozone and water vapour in the austral polar stratospheric vortex and sub-vortex

Directory of Open Access Journals (Sweden)

E. Peet

2004-12-01

Full Text Available In-situ measurements of ozone and water vapour, in the Antarctic lower stratosphere, were made as part of the APE-GAIA mission in September and October 1999. The measurements show a distinct difference above and below the 415K isentrope. Above 415K, the chemically perturbed region of low ozone and water vapour is clearly evident. Below 415K, but still above the tropopause, no sharp meridional gradients in ozone and water vapour were observed. The observations are consistent with analyses of potential vorticity from the European Centre for Medium Range Weather Forecasting, which show smaller radial gradients at 380K than at 450K potential temperature. Ozone loss in the chemically perturbed region above 415K averages 5ppbv per day for mid-September to mid-October. Apparent ozone loss rates in the sub-vortex region are greater, at 7ppbv per day. The data support, therefore, the existence of a sub-vortex region in which meridional transport is more efficient than in the vortex above. The low ozone mixing ratios in the sub-vortex region may be due to in-situ chemical destruction of ozone or transport of ozone-poor air out of the bottom of the vortex. The aircraft data we use cannot distinguish between these two processes. Key words. Meteorology and atmospheric dynamics polar meteorology – Atmospheric composition and structure (middle atmosphere–composition and chemistry

Home blood pressure measurement in elderly patients with cognitive impairment: comparison of agreement between relative-measured blood pressure and automated blood pressure measurement.

Science.gov (United States)

Plichart, Matthieu; Seux, Marie-Laure; Caillard, Laure; Chaussade, Edouard; Vidal, Jean-Sébastien; Boully, Clémence; Hanon, Olivier

2013-08-01

Home blood pressure measurement (HBPM) is recommended by guidelines for hypertension management. However, this method might be difficult to use in elderly individuals with cognitive disorders. Our aim was to assess the agreement and the feasibility of HBPM by a relative as compared with 24-h ambulatory blood pressure monitoring (ABPM) in elderly patients with dementia. Sixty outpatients with dementia aged 75 years and older with office hypertension (≥140/90 mmHg) were subjected successively to HBPM by a trained relative and 24-h ABPM. The order of the two methods was randomized. Current guidelines' thresholds for the diagnosis of hypertension were used. The mean (SD) age of the patients was 80.8 (6.1) years (55% women) and the mean (SD) mini-mental state examination score was 20.1 (6.9). The feasibility of relative-HBPM was very high, with a 97% success rate (defined by ≥12/18 measurements reported). The blood pressure measurements were highly correlated between the two methods (r=0.75 and 0.64 for systolic blood pressure and diastolic blood pressure, respectively; Pmethods for the diagnosis of sustained hypertension and white-coat hypertension was excellent (overall agreement, 92%; κ coefficient, 0.81; 95% CI, 0.61-0.93). Similar results were found for daytime-ABPM. In cognitively impaired elderly patients, HBPM by a relative using an automated device was a good alternative to 24-h ABPM.

Antifungal Activity of Clove Essential Oil and its Volatile Vapour Against Dermatophytic Fungi

OpenAIRE

Chee, Hee Youn; Lee, Min Hee

2007-01-01

Antifungal activities of clove essential oil and its volatile vapour against dermatophytic fungi including Candida albicans, Epidermophyton floccosum. Microsporum audouinii, Trichophyton mentagrophytes, and Trichophyton rubrum were investigated. Both clove essential oil and its volatile vapour strongly inhibit spore germination and mycelial growth of the dermatophytic fungi tested. The volatile vapour of clove essential oil showed fungistatic activity whereas direct application of clove essen...

Comparison of Hexane Vapour Permeation in Two Different Polymeric Membranes via an Innovative In-line FID Detection Method

Directory of Open Access Journals (Sweden)

Z. Petrusová

2017-07-01

Full Text Available This manuscript presents a novel method for the analysis of vapour permeation through polymeric membranes based on in-line analysis of the permeate with an FID detector. The hexane vapour permeation was studied for two commercially available membranes, namely low-density polyethylene (LDPE and thin-film-composite polyamide (PA membrane. The hexane permeation was studied at temperatures of 25–45 °C, hexane vapour activity in the range of 0.2–0.8 and trans-membrane pressures of 5–50 kPa. Two fundamentally different membranes were chosen to demonstrate the potential and sensitivity of the permeation apparatus. Upon increasing the temperature from 25 to 45 °C, the flux in LDPE was found to increase almost fourfold over the whole activity range. The nonlinear increase of the flux with activity indicates plasticization of the polymer by hexane. Contrarily, the flux in the PA membrane increases almost linearly with activity, with only a minor upward curvature. Since the PA is far away from any phase transition, it is less temperature-dependent than LDPE. The activation energy for permeation demonstrates that the temperature dependence in the LDPE membrane is dominated by changes in diffusion, whereas it is dominated by changes in solubility in the PA membrane.

Phase equilibrium at high pressure of heavy oil fraction in propane and n-butane; Equilibrio de fases em alta pressao de fracoes pesadas do petroleo em propano e n-butano

Energy Technology Data Exchange (ETDEWEB)

Canziani, Daniel B.; Ndiaye, Papa M. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Oliveira, Jose V. de; Corazza, Marcos L. [Universidade Regional Integrada, Erechim, RS (Brazil)

2008-07-01

One of the biggest challenge of the oil industry is the preparation and adequacy of existing refineries for processing of heavy oil in large quantities. Specifically aims of this work is to measure phase equilibria date at high-pressure with systems involving GOP (Heavy Gasoil), RAT (Atmospheric Residue) and Marlim (crude oil) in n-butane and propane, using the static-synthetic method. The influence of the addition of methanol on the transition pressure is also investigated. With regard to tests made with the use of methanol as a co-solvent, those with higher levels of methanol (5% in mass fraction) had presented transition pressures a little higher than systems with 1% of methanol and systems without methanol. The systems without methanol showed similar pressures. All systems are PT diagrams of the type Lower Critical Solution Temperature (LCST). Among the solvents used the n-butane shown to be the most soluble for all solutes, in particular for the RAT. With the n-butane were observed only liquid-vapour equilibria, and with propane the liquid-liquid, liquid-liquid-vapour and liquid-liquid-fluid equilibria could be observed. The system Propane-5%Methanol-GOP presented liquid-liquid-vapour transitions, indicates be a diagram of the type V (according to the classification of van Konynenburg and Scott). (author)

Film boiling heat transfer and vapour film collapse for various geometries

International Nuclear Information System (INIS)

Jouhara, H.I.; Axcell, B.P.

2005-01-01

Full text of publication follows: Film boiling heat transfer has application to the safe operation of water-cooled nuclear reactors under fault conditions and it has been studied using nickel-plated copper specimens in transient and steady state experiments. In the transient tests the specimens were held in a water flow; in the steady state investigation a specimen was mounted in an essentially quiescent pool of water. The transient investigation was conducted on two spheres with different diameters, two cylindrical specimens of different lengths in parallel flow, a short cylinder in cross flow and two flat plates with different lengths. The heat transfer coefficient, vapour film thickness (which was estimated from the heat transfer coefficient) and heat flux followed a similar behaviour with changing experimental conditions for all specimens studied. The heat transfer coefficient increased and the vapour film thickness and heat flux decreased as the specimen temperature decreased. As the water subcooling increased the heat transfer coefficient and the heat flux increased while the vapour film thickness decreased. The water velocity was found to have little influence on the film boiling heat transfer results except for the short cylinder in cross flow. The sphere diameter was found to affect the heat transfer results; the heat transfer coefficient and the heat flux were larger, for the larger sphere. No significant effect of the cylinder length on the heat transfer data was observed. However, the heat transfer coefficient was higher (and the average vapour film thinner) for the longer plate than for the shorter plate. Three vapour/liquid interface types were observed namely: 'smooth', 'rippled' and 'turbulent' depending largely on specimen and water temperatures. For all specimens, the maximum heat transfer coefficient, minimum heat flux and minimum film boiling temperature, occurring just before vapour film collapse, were found to increase as the water subcooling

Measuring sub-bandage pressure: comparing the use of pressure monitors and pulse oximeters.

Science.gov (United States)

Satpathy, A; Hayes, S; Dodds, S R

2006-03-01

To test the use of low-cost sub-bandage pressure monitors and pulse oximeters as part of a quality-control measure for graduated compression bandaging in leg ulcer clinics. Twenty-five healthy volunteers (mean age 40 years) providing 50 limbs were bandaged with a four-layer compression bandaging system. The ankle systolic pressure (ASP) was measured using a pulse oximeter (Nellcor NBP-40) before applying the graduated compression bandages. Interface pressure was measured by placing pressure sensors on the skin at three points (2cm above the medial malleolus; the widest part of the calf; and a point midway between them) in the supine and standing positions. The ASP was measured again with the pulse oximeter after the bandage had been applied, and the effect of the bandage on the ASP was recorded. The actual pressure created by the bandage was compared with the required pressure profile. Interface pressures varied with change of position and movement. With the operator blinded to the pressure monitors while applying the bandages, the target pressure of 35-40mmHg at the ankle was achieved in only 36% of limbs ([mean +/- 95% confidence interval]; 32.3 +/- 1.6mmHg [supine]; 38.4 +/- 2.4mmHg [standing position]). With the help of the pressure monitors, the target pressure was achieved in 78% of the limbs. There was no correlation between the pressure monitors and pulse oximeter pressures, demonstrating that the pulse oximeter is not a useful tool for measuring sub-bandage pressures. The results suggest a tool (interface pressure monitors) that is easy to operate should be available as part of quality assurance for treatment, training of care providers and education.

Accuracy assessment of water vapour measurements from in situ and remote sensing techniques during the DEMEVAP 2011 campaign at OHP

Directory of Open Access Journals (Sweden)

O. Bock

2013-10-01

Full Text Available The Development of Methodologies for Water Vapour Measurement (DEMEVAP project aims at assessing and improving humidity sounding techniques and establishing a reference system based on the combination of Raman lidars, ground-based sensors and GPS. Such a system may be used for climate monitoring, radiosonde bias detection and correction, satellite measurement calibration/validation, and mm-level geodetic positioning with Global Navigation Satellite Systems. A field experiment was conducted in September–October 2011 at Observatoire de Haute-Provence (OHP. Two Raman lidars (IGN mobile lidar and OHP NDACC lidar, a stellar spectrometer (SOPHIE, a differential absorption spectrometer (SAOZ, a sun photometer (AERONET, 5 GPS receivers and 4 types of radiosondes (Vaisala RS92, MODEM M2K2-DC and M10, and Meteolabor Snow White participated in the campaign. A total of 26 balloons with multiple radiosondes were flown during 16 clear nights. This paper presents preliminary findings from the analysis of all these data sets. Several classical Raman lidar calibration methods are evaluated which use either Vaisala RS92 measurements, point capacitive humidity measurements, or GPS integrated water vapour (IWV measurements. A novel method proposed by Bosser et al. (2010 is also tested. It consists in calibrating the lidar measurements during the GPS data processing. The methods achieve a repeatability of 4–5%. Changes in the calibration factor of IGN Raman lidar are evidenced which are attributed to frequent optical re-alignments. When modelling and correcting the changes as a linear function of time, the precision of the calibration factors improves to 2–3%. However, the variations in the calibration factor, and hence the absolute accuracy, between methods and types of reference data remain at the level of 7%. The intercomparison of radiosonde measurements shows good agreement between RS92 and Snow White measurements up to 12 km. An overall dry bias is found

A microwave pressure sounder. [for remote measurement of atmospheric pressure

Science.gov (United States)

Peckham, G. E.; Flower, D. A.

1981-01-01

A technique for the remote measurement of atmospheric surface pressure will be described. Such measurements could be made from a satellite in polar orbit and would cover many areas for which conventional meteorological data are not available. An active microwave instrument is used to measure the strength of return echoes from the ocean surface at a number of frequencies near the 60 GHz oxygen absorption band. Factors which affect the accuracy with which surface pressure can be deduced from these measurements will be discussed and an instrument designed to test the method by making measurements from an aircraft will be described.

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.

Rate Constants for the Reactions of OH with CO, NO and NO2, and of HO2 with NO2 in the Presence of Water Vapour at Lower-Tropospheric Conditions

Science.gov (United States)

Rolletter, Michael; Fuchs, Hendrik; Novelli, Anna; Ehlers, Christian; Hofzumahaus, Andreas

2016-04-01

Recent studies have shown that the chemistry of gaseous nitrous acid (HONO) in the lower troposphere is not fully understood. Aside from heterogenous reactions, the daytime HONO formation in the gas-phase is not well understood (Li et al., Science, 2014). For a better understanding of HONO in the gas-phase, we have reinvestigated the reaction rate constants of important tropospheric reactions of the HOx radical family (OH and HO2) with nitrogen oxides at realistic conditions of the lower troposphere (at ambient temperature/pressure and in humid air). In this study we apply a direct pump and probe technique with high accuracy, using small radical concentrations to avoid secondary chemistry. Pulsed laser photolysis/laser-induced fluorescence (LP/LIF) was used to investigate the reaction rate constants of OH with CO, NO, NO2, and HO2 with NO2 in synthetic air at different water vapor concentrations (up to 5 x 1017 molecules cm-3). Photolysis of ozone in the presence of gaseous water was the source of OH. The reactions took place in a flow-tube at room temperature and atmospheric pressure. The chemical decay of the radicals was monitored by laser-induced fluorescence detection in a low-pressure cell, which sampled air continuously from the end of the flow-tube. Knowing the reactant concentrations subsequently allowed to calculate the bimolecular reaction rate constants at 1 atm from the pseudo-first-order decays. In order to observe HO2 reactions, OH was converted into HO2 with an excess of CO in the flow-tube. The newly measured rate constants for OH with CO, NO and NO2 agree very well with current recommendations by NASA/JPL and IUPAC and have an improved accuracy (uncertainty < 5%). These rate coefficients are independent of the presence of water vapour. The measured rate constant of HO2 with NO2 was found to depend significantly on the water-vapour concentration (probably due to formation of HO2*H2O complexes) and to exceed current recommendations by NASA/JPL and

Terminal drought-tolerant pearl millet [Pennisetum glaucum (L.) R. Br.] have high leaf ABA and limit transpiration at high vapour pressure deficit.

Science.gov (United States)

Kholová, Jana; Hash, C T; Kumar, P Lava; Yadav, Rattan S; Kocová, Marie; Vadez, Vincent

2010-03-01

It was previously shown that pearl millet genotypes carrying a terminal drought tolerance quantitative trait locus (QTL) had a lower transpiration rate (Tr; g cm(-2) d(-1)) under well-watered conditions than sensitive lines. Here experiments were carried out to test whether this relates to leaf abscisic acid (ABA) and Tr concentration at high vapour pressure deficit (VPD), and whether that leads to transpiration efficiency (TE) differences. These traits were measured in tolerant/sensitive pearl millet genotypes, including near-isogenic lines introgressed with a terminal drought tolerance QTL (NIL-QTLs). Most genotypic differences were found under well-watered conditions. ABA levels under well-watered conditions were higher in tolerant genotypes, including NIL-QTLs, than in sensitive genotypes, and ABA did not increase under water stress. Well-watered Tr was lower in tolerant than in sensitive genotypes at all VPD levels. Except for one line, Tr slowed down in tolerant lines above a breakpoint at 1.40-1.90 kPa, with the slope decreasing >50%, whereas sensitive lines showed no change in that Tr response across the whole VPD range. It is concluded that two water-saving (avoidance) mechanisms may operate under well-watered conditions in tolerant pearl millet: (i) a low Tr even at low VPD conditions, which may relate to leaf ABA; and (ii) a sensitivity to higher VPD that further restricts Tr, which suggests the involvement of hydraulic signals. Both traits, which did not lead to TE differences, could contribute to absolute water saving seen in part due to dry weight increase differences. This water saved would become critical for grain filling and deserves consideration in the breeding of terminal drought-tolerant lines.

Some thermodynamic properties of liquid ammonia and trideuteroammonia

International Nuclear Information System (INIS)

Streatfield, M.H.; Henderson, C.; Staveley, L.A.K.

1987-01-01

The orthobaric density of liquid NH 3 has been measured from about 200 to 287 K, and for liquid ND 3 from about 205 to 273 K. The molar volume of liquid NH 3 exceeds that of ND 3 by between 0.8 and 0.9 per cent. The difference of the vapour pressures of the two compounds has been measured from about 200 to 266 K, and the vapour pressure of NH 3 from the triple-point temperature to 234 K. Liquid NH 3 has the higher vapour pressure, the difference being relatively large for a pair of isotopic compounds. At 200 K, the ratio of the vapour pressure of NH 3 to that of ND 3 is about 1.2. The available vapour pressures for NH 3 have been fitted to a Wagner equation. By combining vapour pressures derived from this equation with the differential measurements, values for the vapour pressure of ND 3 have been obtained. These values have likewise been fitted to a Wagner equation. The material presented in this paper has been used to estimate the molar enthalpies of vaporization of NH 3 (l) and of ND 3 (l) from the triple-point temperatures to 290 K. The molar enthalpy of vaporization of ND 3 exceeds that of NH 3 throughout this range. The difference amounts to about 3.5 per cent at the triple-point temperatures, and decreases with rising temperature. (author)

Void fraction measurement in two-phase flow with X-rays

International Nuclear Information System (INIS)

Hufschmidt, W.; Clercq, E. de.

1984-01-01

The exact knowledge of the void fraction in two-phase flow systems with water and vapour is of great importance for water-reactors. A mesurement method not disturbing the fluid flow is the absorption technique X-rays. This method has been tested for the present case of small absorption lengths (about 16mm). In collaboration with the 'Lehrstuhl fuer elektronische Schaltungen' of the Ruhruniversitaet, Bochum (FRG), a rapid measurement device has been developed using ionization chambers. At present steady-state fluid in vertical tubes with homogeneous distribution of the two-phases water-vapour are tested at pressures in the range from 70 to 150 bars and rather good agreements with calculated values are found

Antifungal activity of clove essential oil and its volatile vapour against dermatophytic fungi.

Science.gov (United States)

Chee, Hee Youn; Lee, Min Hee

2007-12-01

Antifungal activities of clove essential oil and its volatile vapour against dermatophytic fungi including Candida albicans, Epidermophyton floccosum. Microsporum audouinii, Trichophyton mentagrophytes, and Trichophyton rubrum were investigated. Both clove essential oil and its volatile vapour strongly inhibit spore germination and mycelial growth of the dermatophytic fungi tested. The volatile vapour of clove essential oil showed fungistatic activity whereas direct application of clove essential oil showed fungicidal activity.

Influence of water vapour and permanent gases on the atmospheric optical depths and transmittance

Science.gov (United States)

Badescu, V.

1991-05-01

The influence of the atmospheric state on the extinction of direct solar radiation has been studied by using a four layer atmospheric model. Simple analytical formulae are established for the spectral optical depths of permanent gases and water vapour. These formulae use the ground level values of air pressure, temperature and relative huniidity. An additional parameter, related to the vertical distribution of the hunmidity content, is used for a better estimation of the water vapour optical depth. Good agreement between theory and measurements is found. The paper shows the dependence of the atmospheric spectral transmittance on the above mentioned parameters. L'influence de l'état atmosphérique sur l'extinction de la radiation solaire directe a été étudiée à l'aide d'un modèle atmosphérique développé antérieurement par l'auteur. Des formules simples ont été établies pour l'épaisseur optique spectrale des gaz et de la vapeur d'eau. Ces formules utilisent les valeurs de la pression atmosphérique, de la température et de l'humidité relative, mesurées au niveau du sol. Un paramètre supplémentaire, lié à la distribution verticale du contenu d'humidité, est utilisé pour calculer l'épaisseur optique due à la vapeur d'eau. La théorie est en bon accord avec les résultats des mesures. Le travail montre la dépendance de la transmittance atmosphérique spectrale en fonction des paramètres spécifiés ci-dessus.

A whole-air relaxed eddy accumulation measurement system for sampling vertical vapour exchange of elemental mercury

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Jonas Sommar

2013-11-01

Full Text Available An apparatus relying on relaxed eddy accumulation (REA methodology has been designed and developed for continuous-field measurements of vertical Hg0 fluxes over cropland ecosystems. This micro-meteorological technique requires sampling of turbulent eddies into up- and downdraught channels at a constant flow rate and accurate timing, based on a threshold involving the sign of vertical wind component (w. The fully automated system is of a whole-air type drawing air at a high velocity to the REA sampling apparatus and allowing for the rejection of samples associated with w-fluctuations around zero. Conditional sampling was executed at 10-Hz resolution on a sub-stream by two fast-response three-way solenoid switching valves connected in parallel to a zero Hg0 air supply through their normally open ports. To suppress flow transients resulting from switching, pressure differentials across the two upstream ports of the conditional valves were minimised using a control unit. The Hg0 concentrations of the up- and downdraught channel were sequentially (each by two consecutive 5-minute gas samples determined after enhancement collection onto gold traps by an automated cold vapour atomic fluorescence spectrophotometer (CVAFS instrument. A protocol of regular reference sampling periods was implemented during field campaigns to continuously adjust for bias that may exist between the two conditional sampling channels. Using a 5-minute running average was conditional threshold, nearly-constant relaxation coefficients (β s of ~0.56 were determined during two bi-weekly field deployments when turbulence statistics were assured for good quality, in accordance with previously reported estimates. The fully developed REA-CVAFS system underwent Hg0 flux field trial runs at a winter wheat cropland located in the North China Plain. Over a 15-d period during early May 2012, dynamic, often bi-directional, fluxes were observed during the course of a day with a tendency of

Blood pressure and anthropometric measurements in healthy ...

African Journals Online (AJOL)

Methods. We measured the blood pressures of 650 healthy, randomly ... In addition, blood pressure measurement should be a part of the routine clinical examination of children. ... familial risk factors.2 ... common cause of elevated blood pressure in children.4 They ... sphygmomanometer (Accoson, hospital model BS 274,.

Global distributions of water vapour isotopologues retrieved from IMG/ADEOS data

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H. Herbin

2007-07-01

Full Text Available The isotopologic composition of water vapour in the atmosphere provides valuable information on many climate, chemical and dynamical processes. The accurate measurements of the water isotopologues by remote-sensing techniques remains a challenge, due to the large spatial and temporal variations. Simultaneous profile retrievals of the main water isotopologues (i.e. H₂¹⁶O, H₂¹⁸O and HDO and their ratios are presented here for the first time, along their retrieved global distributions. The results are obtained by exploiting the high resolution infrared spectra recorded by the Interferometric Monitor for Greenhouse gases (IMG instrument, which has operated in the nadir geometry onboard the ADEOS satellite between 1996 and 1997. The retrievals are performed on cloud-free radiances, measured during ten days of April 1997, considering two atmospheric windows (1205–1228 cm⁻¹; 2004–2032 cm⁻¹ and using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM. Characterizations in terms of vertical sensitivity and error budget are provided. We show that a relatively high vertical resolution is achieved for H₂¹⁶O (~4–5 km, and that the retrieved profiles are in fair agreement with local sonde measurements, at different latitudes. The retrieved global distributions of H₂¹⁶O, H₂¹⁸O, HDO and their ratios are presented and found to be consistent with previous experimental studies and models. The Ocean-Continent difference, the latitudinal and vertical dependence of the water vapour amount and the isotopologic depletion are notably well reproduced. Others trends, possibly related to small-scale variations in the vertical profiles are also discussed. Despite the difficulties encountered for computing accurately the isotopologic ratios, our results demonstrate the ability

Swelling behaviour of Early Jurassic shales when exposed to water vapour

Science.gov (United States)

Houben, Maartje; Barnhoorn, Auke; Peach, Colin; Drury, Martyn

2017-04-01

The presence of water in mudrocks has a largely negative impact on production of gas, due to the fact that water causes swelling of the rock. Removing the water from the mudrock on the other hand could potentially shrink the rock and increase the matrix permeability. Investigation of the swelling/shrinkage behaviour of the rock during exposure to water vapour is of key importance in designing and optimizing unconventional production strategies. We have used outcrop samples of the Whitby Mudstone and the Posidonia shale [1], potential unconventional sources for gas in North-western Europe, to measure the swelling and shrinkage behaviour. Subsamples, 1 mm cubes, were prepared by the Glass Workshop at Utrecht University using a high precision digitally controlled diamond wafering saw cooled by air. The mm cubes were then exposed to atmospheres with different relative humidities either in an Environmental Scanning Electron Microscope (ESEM) or in a 3D dilatometer. So that the sample responses to exposure of water vapour could be measured. Parallel to the bedding we found a swelling strain between 0.5 and 1.5 %, perpendicular to the bedding though swelling strain varied between 1 and 3.5%. Volumetric swelling strain varied between 1 and 2% at a maximum relative humidity of 95%. Volumetric swelling strains measured in the Early Toarcian Shales are similar to the ones found in coal [2], where the results suggest that it might be possible to increase permeability in the reservoir by decreasing the in-situ water activity due to shrinkage of the matrix. [1] M.E. Houben, A. Barnhoorn, L. Wasch, J. Trabucho-Alexandre, C. J. Peach, M.R. Drury (2016). Microstructures of Early Jurassic (Toarcian) shales of Northern Europe, International Journal of Coal Geology, 165, 76-89. [2] Jinfeng Liu, Colin J. Peach, Christopher J. Spiers (2016). Anisotropic swelling behaviour of coal matrix cubes exposed to water vapour: Effects of relative humidity and sample size, International Journal of

A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

International Nuclear Information System (INIS)

Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

2016-01-01

In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere

Directory of Open Access Journals (Sweden)

V. Barabash

2014-03-01

Full Text Available Mesospheric water vapour concentration effects on the ion composition and electron density in the lower ionosphere under quiet geophysical conditions were examined. Water vapour is an important compound in the mesosphere and the lower thermosphere that affects ion composition due to hydrogen radical production and consequently modifies the electron number density. Recent lower-ionosphere investigations have primarily concentrated on the geomagnetic disturbance periods. Meanwhile, studies on the electron density under quiet conditions are quite rare. The goal of this study is to contribute to a better understanding of the ionospheric parameter responses to water vapour variability in the quiet lower ionosphere. By applying a numerical D region ion chemistry model, we evaluated efficiencies for the channels forming hydrated cluster ions from the NO+ and O2+ primary ions (i.e. NO+.H2O and O2+.H2O, respectively, and the channel forming H+(H2On proton hydrates from water clusters at different altitudes using profiles with low and high water vapour concentrations. Profiles for positive ions, effective recombination coefficients and electrons were modelled for three particular cases using electron density measurements obtained during rocket campaigns. It was found that the water vapour concentration variations in the mesosphere affect the position of both the Cl2+ proton hydrate layer upper border, comprising the NO+(H2On and O2+(H2On hydrated cluster ions, and the Cl1+ hydrate cluster layer lower border, comprising the H+(H2On pure proton hydrates, as well as the numerical cluster densities. The water variations caused large changes in the effective recombination coefficient and electron density between altitudes of 75 and 87 km. However, the effective recombination coefficient, αeff, and electron number density did not respond even to large water vapour concentration variations occurring at other altitudes in the mesosphere. We determined the water

The Seasonal Cycle of Water Vapour on Mars from Assimilation of Thermal Emission Spectrometer Data

Science.gov (United States)

Steele, Liam J.; Lewis, Stephen R.; Patel, Manish R.; Montmessin, Franck; Forget, Francois; Smith, Michael D.

2014-01-01

We present for the first time an assimilation of Thermal Emission Spectrometer (TES) water vapour column data into a Mars global climate model (MGCM). We discuss the seasonal cycle of water vapour, the processes responsible for the observed water vapour distribution, and the cross-hemispheric water transport. The assimilation scheme is shown to be robust in producing consistent reanalyses, and the global water vapour column error is reduced to around 2-4 pr micron depending on season. Wave activity is shown to play an important role in the water vapour distribution, with topographically steered flows around the Hellas and Argyre basins acting to increase transport in these regions in all seasons. At high northern latitudes, zonal wavenumber 1 and 2 stationary waves during northern summer are responsible for spreading the sublimed water vapour away from the pole. Transport by the zonal wavenumber 2 waves occurs primarily to the west of Tharsis and Arabia Terra and, combined with the effects of western boundary currents, this leads to peak water vapour column abundances here as observed by numerous spacecraft. A net transport of water to the northern hemisphere over the course of one Mars year is calculated, primarily because of the large northwards flux of water vapour which occurs during the local dust storm around L(sub S) = 240-260deg. Finally, outlying frost deposits that surround the north polar cap are shown to be important in creating the peak water vapour column abundances observed during northern summer.

Comparison of interaction mechanisms of copper phthalocyanine and nickel phthalocyanine thin films with chemical vapours

Science.gov (United States)

Ridhi, R.; Singh, Sukhdeep; Saini, G. S. S.; Tripathi, S. K.

2018-04-01

The present study deals with comparing interaction mechanisms of copper phthalocyanine and nickel phthalocyanine with versatile chemical vapours: reducing, stable aromatic and oxidizing vapours namely; diethylamine, benzene and bromine. The variation in electrical current of phthalocyanines with exposure of chemical vapours is used as the detection parameter for studying interaction behaviour. Nickel phthalocyanine is found to exhibit anomalous behaviour after exposure of reducing vapour diethylamine due to alteration in its spectroscopic transitions and magnetic states. The observed sensitivities of copper phthalocyanine and nickel phthalcyanine films are different in spite of their similar bond numbers, indicating significant role of central metal atom in interaction mechanism. The variations in electronic transition levels after vapours exposure, studied using UV-Visible spectroscopy confirmed our electrical sensing results. Bromine exposure leads to significant changes in vibrational bands of metal phthalocyanines as compared to other vapours.

Assessing pharmacy students' ability to accurately measure blood pressure using a blood pressure simulator arm.

Science.gov (United States)

Bottenberg, Michelle M; Bryant, Ginelle A; Haack, Sally L; North, Andrew M

2013-06-12

To compare student accuracy in measuring normal and high blood pressures using a simulator arm. In this prospective, single-blind, study involving third-year pharmacy students, simulator arms were programmed with prespecified normal and high blood pressures. Students measured preset normal and high diastolic and systolic blood pressure using a crossover design. One hundred sixteen students completed both blood pressure measurements. There was a significant difference between the accuracy of high systolic blood pressure (HSBP) measurement and normal systolic blood pressure (NSBP) measurement (mean HSBP difference 8.4 ± 10.9 mmHg vs NSBP 3.6 ± 6.4 mmHg; pdifference between the accuracy of high diastolic blood pressure (HDBP) measurement and normal diastolic blood pressure (NDBP) measurement (mean HDBP difference 6.8 ± 9.6 mmHg vs. mean NDBP difference 4.6 ± 4.5 mmHg; p=0.089). Pharmacy students may need additional instruction and experience with taking high blood pressure measurements to ensure they are able to accurately assess this important vital sign.

Assessing Pharmacy Students’ Ability to Accurately Measure Blood Pressure Using a Blood Pressure Simulator Arm

Science.gov (United States)

Bryant, Ginelle A.; Haack, Sally L.; North, Andrew M.

2013-01-01

Objective. To compare student accuracy in measuring normal and high blood pressures using a simulator arm. Methods. In this prospective, single-blind, study involving third-year pharmacy students, simulator arms were programmed with prespecified normal and high blood pressures. Students measured preset normal and high diastolic and systolic blood pressure using a crossover design. Results. One hundred sixteen students completed both blood pressure measurements. There was a significant difference between the accuracy of high systolic blood pressure (HSBP) measurement and normal systolic blood pressure (NSBP) measurement (mean HSBP difference 8.4 ± 10.9 mmHg vs NSBP 3.6 ± 6.4 mmHg; pdifference between the accuracy of high diastolic blood pressure (HDBP) measurement and normal diastolic blood pressure (NDBP) measurement (mean HDBP difference 6.8 ± 9.6 mmHg vs. mean NDBP difference 4.6 ± 4.5 mmHg; p=0.089). Conclusions. Pharmacy students may need additional instruction and experience with taking high blood pressure measurements to ensure they are able to accurately assess this important vital sign. PMID:23788809

Automated measurement of pressure injury through image processing.

Science.gov (United States)

Li, Dan; Mathews, Carol

2017-11-01

To develop an image processing algorithm to automatically measure pressure injuries using electronic pressure injury images stored in nursing documentation. Photographing pressure injuries and storing the images in the electronic health record is standard practice in many hospitals. However, the manual measurement of pressure injury is time-consuming, challenging and subject to intra/inter-reader variability with complexities of the pressure injury and the clinical environment. A cross-sectional algorithm development study. A set of 32 pressure injury images were obtained from a western Pennsylvania hospital. First, we transformed the images from an RGB (i.e. red, green and blue) colour space to a YC b C r colour space to eliminate inferences from varying light conditions and skin colours. Second, a probability map, generated by a skin colour Gaussian model, guided the pressure injury segmentation process using the Support Vector Machine classifier. Third, after segmentation, the reference ruler - included in each of the images - enabled perspective transformation and determination of pressure injury size. Finally, two nurses independently measured those 32 pressure injury images, and intraclass correlation coefficient was calculated. An image processing algorithm was developed to automatically measure the size of pressure injuries. Both inter- and intra-rater analysis achieved good level reliability. Validation of the size measurement of the pressure injury (1) demonstrates that our image processing algorithm is a reliable approach to monitoring pressure injury progress through clinical pressure injury images and (2) offers new insight to pressure injury evaluation and documentation. Once our algorithm is further developed, clinicians can be provided with an objective, reliable and efficient computational tool for segmentation and measurement of pressure injuries. With this, clinicians will be able to more effectively monitor the healing process of pressure

Water vapour retrieval using the Precision Solar Spectroradiometer

Science.gov (United States)

Raptis, Panagiotis-Ioannis; Kazadzis, Stelios; Gröbner, Julian; Kouremeti, Natalia; Doppler, Lionel; Becker, Ralf; Helmis, Constantinos

2018-02-01

The Precision Solar Spectroradiometer (PSR) is a new spectroradiometer developed at Physikalisch-Meteorologisches Observatorium Davos - World Radiation Center (PMOD-WRC), Davos, measuring direct solar irradiance at the surface, in the 300-1020 nm spectral range and at high temporal resolution. The purpose of this work is to investigate the instrument's potential to retrieve integrated water vapour (IWV) using its spectral measurements. Two different approaches were developed in order to retrieve IWV: the first one uses single-channel and wavelength measurements, following a theoretical water vapour high absorption wavelength, and the second one uses direct sun irradiance integrated at a certain spectral region. IWV results have been validated using a 2-year data set, consisting of an AERONET sun-photometer Cimel CE318, a Global Positioning System (GPS), a microwave radiometer profiler (MWP) and radiosonde retrievals recorded at Meteorological Observatorium Lindenberg, Germany. For the monochromatic approach, better agreement with retrievals from other methods and instruments was achieved using the 946 nm channel, while for the spectral approach the 934-948 nm window was used. Compared to other instruments' retrievals, the monochromatic approach leads to mean relative differences up to 3.3 % with the coefficient of determination (R2) being in the region of 0.87-0.95, while for the spectral approach mean relative differences up to 0.7 % were recorded with R2 in the region of 0.96-0.98. Uncertainties related to IWV retrieval methods were investigated and found to be less than 0.28 cm for both methods. Absolute IWV deviations of differences between PSR and other instruments were determined the range of 0.08-0.30 cm and only in extreme cases would reach up to 15 %.

Impact of major volcanic eruptions on stratospheric water vapour

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M. Löffler

2016-05-01

Full Text Available Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry–climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg – Modular Earth Submodel System (ECHAM/MESSy Atmospheric Chemistry (EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño–Southern Oscillation (ENSO are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

Spontaneuos and Parametric Processes in Warm Rubidium Vapours

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Dąbrowski M.

2014-12-01

Full Text Available Warm rubidium vapours are known to be a versatile medium for a variety of experiments in atomic physics and quantum optics. Here we present experimental results on producing the frequency converted light for quantum applications based on spontaneous and stimulated processes in rubidium vapours. In particular, we study the efficiency of spontaneously initiated stimulated Raman scattering in the Λ-level configuration and conditions of generating the coherent blue light assisted by multi-photon transitions in the diamond-level configuration. Our results will be helpful in search for new types of interfaces between light and atomic quantum memories.

Development of a test method for distillation of diesel-biodiesel-alcohols mixtures at reduced pressure

Science.gov (United States)

Niculescu, R.; Iosub, I.; Clenci, A.; Zaharia, C.; Iorga-Simăn, V.

2017-10-01

Increased environmental awareness and depletion of fossil petroleum resources are driving the automotive industry to seek out and use alternative fuels. For instance, the biofuel is a major renewable energy source to supplement declining fossil fuel resources. The addition of alcohols like methanol and ethanol is practical in biodiesel blends due to its miscibility with the pure biodiesel. Alcohols also improve physico-chemical properties of biodiesel blends, which lead to improved combustion efficiency. Proper volatility of fuels is critical to the operation of internal combustion engines with respect to both performance and emissions. Volatility may be characterised by various measurements, the most common of which are vapour pressure, distillation and the vapour/liquid ratio. The presence of ethanol or other oxygenates may affect these properties and, as a result, performance and emissions, as well. However, in the case of diesel-biodiesel-alcohols mixtures, the variance of component volatility makes difficult the analysis of the overall volatility. Thus, the paper presents an experimental method of distilling diesel-biodiesel-alcohols mixtures by adjusting the boiler pressure of an i-Fischer Dist equipment.

Developing a western Siberia reference site for tropospheric water vapour isotopologue observations obtained by different techniques (in situ and remote sensing

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K. Gribanov

2014-06-01

water cycle, affected by changes in air mass origin, non-convective and convective processes and continental recycling. Novel remote sensing and in situ measuring techniques have recently offered opportunities for monitoring atmospheric water vapour isotopic composition. Recently developed infrared laser spectrometers allow for continuous in situ measurements of surface water vapour δDv and δ18Ov. So far, very few intercomparisons of measurements conducted using different techniques have been achieved at a given location, due to difficulties intrinsic to the comparison of integrated with local measurements. Nudged simulations conducted with high-resolution isotopically enabled general circulation models (GCMs provide a consistent framework for comparison with the different types of observations. Here, we compare simulations conducted with the ECHAM5-wiso model with two types of water vapour isotopic data obtained during summer 2012 at the forest site of Kourovka, western Siberia: hourly ground-based FTIR total atmospheric columnar δDv amounts, and in situ hourly Picarro δDv measurements. There is an excellent correlation between observed and predicted δDv at surface while the comparison between water column values derived from the model compares well with FTIR estimates.

Development of a Blood Pressure Measurement Instrument with Active Cuff Pressure Control Schemes

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Chung-Hsien Kuo

2017-01-01

Full Text Available This paper presents an oscillometric blood pressure (BP measurement approach based on the active control schemes of cuff pressure. Compared with conventional electronic BP instruments, the novelty of the proposed BP measurement approach is to utilize a variable volume chamber which actively and stably alters the cuff pressure during inflating or deflating cycles. The variable volume chamber is operated with a closed-loop pressure control scheme, and it is activated by controlling the piston position of a single-acting cylinder driven by a screw motor. Therefore, the variable volume chamber could significantly eliminate the air turbulence disturbance during the air injection stage when compared to an air pump mechanism. Furthermore, the proposed active BP measurement approach is capable of measuring BP characteristics, including systolic blood pressure (SBP and diastolic blood pressure (DBP, during the inflating cycle. Two modes of air injection measurement (AIM and accurate dual-way measurement (ADM were proposed. According to the healthy subject experiment results, AIM reduced 34.21% and ADM reduced 15.78% of the measurement time when compared to a commercial BP monitor. Furthermore, the ADM performed much consistently (i.e., less standard deviation in the measurements when compared to a commercial BP monitor.

The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding

Energy Technology Data Exchange (ETDEWEB)

N' Dri Koffi, Ernest; Maetzler, Christian [Bern Univ. (Switzerland). Inst. of Applied Physics; Graham, Edward [Bern Univ. (Switzerland). Inst. of Applied Physics; University of the Highlands and Islands, Stornoway, Scotland (United Kingdom). Lews Castle College

2013-10-15

The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the 'Swiss box') to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 x 10{sup 7} kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the Swiss box 'import' more water vapour than it 'exports', but the amount gained remains only a small fraction (1% to 5%) of the total available water vapour passing by. High inward water vapour fluxes are not necessarily linked to high precipitation episodes. The water vapour flux during the August 2005 floods, which caused severe damage in central Switzerland, is examined and an assessment is made of the computed water vapour fluxes compared to high spatio-temporal rain gauge and radar observations. About 25% of the incoming water vapour flux was stored in Switzerland. The computed water vapour fluxes from ECMWF data compare well with the mean rain gauge observations and the combined rain-gauge radar precipitation products. (orig.)

The water vapour continuum in near-infrared windows - Current understanding and prospects for its inclusion in spectroscopic databases

Science.gov (United States)

Shine, Keith P.; Campargue, Alain; Mondelain, Didier; McPheat, Robert A.; Ptashnik, Igor V.; Weidmann, Damien

2016-09-01

Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth's atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm-1) and include reference to the window centred on 2600 cm-1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback - cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum - as an example, we

Pressure measurements in harsh environments

International Nuclear Information System (INIS)

Cook, C.W.; Ames, E.S.

1979-01-01

A fluid coupled plate (FCP) gage was designed which allows pressure measurements to be made in harsh environments (including debris) using conventional pressure transducers. The pressure transducer is isolated by means of a rigid force plate which is supported by a bellows having one corrugation. This portion of the gage is machined from a single piece of material. The interior of the gage is filled with a phenol fluid which has a low compressibility

Retrieval of total water vapour in the Arctic using microwave humidity sounders

Science.gov (United States)

Cristian Scarlat, Raul; Melsheimer, Christian; Heygster, Georg

2018-04-01

Quantitative retrievals of atmospheric water vapour in the Arctic present numerous challenges because of the particular climate characteristics of this area. Here, we attempt to build upon the work of Melsheimer and Heygster (2008) to retrieve total atmospheric water vapour (TWV) in the Arctic from satellite microwave radiometers. While the above-mentioned algorithm deals primarily with the ice-covered central Arctic, with this work we aim to extend the coverage to partially ice-covered and ice-free areas. By using modelled values for the microwave emissivity of the ice-free sea surface, we develop two sub-algorithms using different sets of channels that deal solely with open-ocean areas. The new algorithm extends the spatial coverage of the retrieval throughout the year but especially in the warmer months when higher TWV values are frequent. The high TWV measurements over both sea-ice and open-water surfaces are, however, connected to larger uncertainties as the retrieval values are close to the instrument saturation limits.This approach allows us to apply the algorithm to regions where previously no data were available and ensures a more consistent physical analysis of the satellite measurements by taking into account the contribution of the surface emissivity to the measured signal.

Measuring Viscosities of Gases at Atmospheric Pressure

Science.gov (United States)

Singh, Jag J.; Mall, Gerald H.; Hoshang, Chegini

1987-01-01

Variant of general capillary method for measuring viscosities of unknown gases based on use of thermal mass-flowmeter section for direct measurement of pressure drops. In technique, flowmeter serves dual role, providing data for determining volume flow rates and serving as well-characterized capillary-tube section for measurement of differential pressures across it. New method simple, sensitive, and adaptable for absolute or relative viscosity measurements of low-pressure gases. Suited for very complex hydrocarbon mixtures where limitations of classical theory and compositional errors make theoretical calculations less reliable.

measurements and analysis of some meteorological elements in ...

African Journals Online (AJOL)

Measurements of relative humidity, dew point and vapour pressure at Uturu (Lat. 05.33°N and 06.03°N, and long, 07.10°E and 07.29°E) were carried out. The data were collected in a synoptic hour, that is at 3 hours interval starting from 9am to 6pm each day for the months of February, March, and July using whirling ...

Seasonally-Active Water on Mars: Vapour, Ice, Adsorbate, and the Possibility of Liquid

Science.gov (United States)

Richardson, M. I.

2002-12-01

southern caps. Similar climate-models of the water cycle also do not need much exchangeable adsorbed water in order to explain the observed vapour distributions. The possibility of liquid water is tantalizing, but difficult to definitively judge. On scales greater than a meter or so, Mars is most definitely well away from the water triple point--although the surface pressure can exceed 6.1 mbars, the partial pressure of water vapor (to which the triple point refers) is at best orders of magnitude lower. Several careful studies have shown, however, that locally transient (meta-stable) liquid is possible, if the net heating of ice deposits is high enough. This process is aided if the total surface pressure exceeds 6.1mbar (this prevents boiling, or the explosive loss of vapour into the atmosphere) or if the liquid is covered by a thin ice shell, and is only possible if surface temperatures exceed 273K (for pure water, or the appropriate eutectic for brines) and if ice is present. The former challenge is much easier to meet than the latter. The melt scenario requires that ice deposited in winter must be protected from sublimation as surface temperatures increase in spring, but then exposed to the peak of solar heating in summer. Available spacecraft observations of seasonal water will be discussed with the aid of GCM model simulations, and examined in the context of water distributions and phases.

Study of the Quantum Efficiency of CsI Photocathodes Exposed to Oxygen and Water Vapour

CERN Document Server

Di Mauro, A; Piuz, François; Schyns, E M; Van Beelen, J B; Williams, T D

2000-01-01

The operation of CsI photocathodes in gaseous detectors requires special attention to the purity of the applied gas mixtures.We have studied the influence of oxygen and water vapour contaminations on the performance of CsI photocathodes for theALICE HMPID RICH prototype. Measurements were done through comparison of Cherenkov rings obtained from beamtests. Increased levels of oxygen and water vapour did not show any effect on the performance. The results of this studyfound a direct application in the way of storing CsI photocathodes over long periods nad in particular in the shipment of theHMPID prototype from CERN to the STAR experiment at BNL. (Abstract only available,full text to follow)

Pressure measurements in magnetic-fusion devices

International Nuclear Information System (INIS)

Dylla, H.F.

1981-11-01

Accurate pressure measurements are important in magnetic fusion devices for: (1) plasma diagnostic measurements of particle balance and ion temperature; (2) discharge cleaning optimization; (3) vacuum system performance; and (4) tritium accountability. This paper reviews the application, required accuracy, and suitable instrumentation for these measurements. Demonstrated uses of ionization-type and capacitance-diaphragm gauges for various pressure and gas-flow measurements in tokamaks are presented, with specific reference to the effects of magnetic fields on gauge performance and the problems associated with gauge calibration

Pressure measurements in magnetic-fusion devices

Energy Technology Data Exchange (ETDEWEB)

Dylla, H.F.

1981-11-01

Accurate pressure measurements are important in magnetic fusion devices for: (1) plasma diagnostic measurements of particle balance and ion temperature; (2) discharge cleaning optimization; (3) vacuum system performance; and (4) tritium accountability. This paper reviews the application, required accuracy, and suitable instrumentation for these measurements. Demonstrated uses of ionization-type and capacitance-diaphragm gauges for various pressure and gas-flow measurements in tokamaks are presented, with specific reference to the effects of magnetic fields on gauge performance and the problems associated with gauge calibration.

Factors affecting release of ethanol vapour in active modified atmosphere packaging systems for horticultural products

Directory of Open Access Journals (Sweden)

Weerawate Utto

2014-04-01

Full Text Available The active modified atmosphere packaging (active MAP system , which provides interactive postharvest control , using ethanol vapour controlled release, is one of the current interests in the development of active packaging for horticultural products. A number of published research work have discussed the relationship between the effectiveness of ethanol vapour and its concentration in the package headspace, including its effect on postharvest decay and physiological controls. This is of importance because a controlled release system should release and maintain ethanol vapour at effective concentrations during the desired storage period. A balance among the mass transfer processes of ethanol vapour in the package results in ethanol vapour accumulation in the package headspace. Key factors affecting these processes include ethanol loading, packaging material, packaged product and storage environment (temperature and relative h umidity. This article reviews their influences and discusses future work required to better understand their influences on ethanol vapour release and accumulations in active MAP.

Intraocular pressure measurement in patients with previous LASIK surgery using pressure phosphene tonometer.

Science.gov (United States)

Cheng, Arthur C K; Leung, Dexter Y L; Cheung, Eva Y Y; Fan, Dorothy S P; Law, Ricky W K; Lam, Dennis S C

2005-04-01

To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry. Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t-test, Pearson's correlation test and Bland-Altman plotting. There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean +/-SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 +/- 2.77 mmHg (P contact tonometry significantly underestimated IOP measurement by 9.96 +/- 2.25 mmHg (P < 0.001). Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients.

Organic Vapour Sensing Properties of Area-Ordered and Size-Controlled Silicon Nanopillar

Directory of Open Access Journals (Sweden)

Wei Li

2016-11-01

Full Text Available Here, a silicon nanopillar array (Si-NPA was fabricated. It was studied as a room-temperature organic vapour sensor, and the ethanol and acetone gas sensing properties were detected with I-V curves. I-V curves show that these Si-NPA gas sensors are sensitive to ethanol and acetone organic vapours. The turn-on threshold voltage is about 0.5 V and the operating voltage is 3 V. With 1% ethanol gas vapour, the response time is 5 s, and the recovery time is 15 s. Furthermore, an evaluation of the gas sensor stability for Si-NPA was performed. The gas stability results are acceptable for practical detections. These excellent sensing characteristics can mainly be attributed to the change of the overall dielectric constant of Si-NPA caused by the physisorption of gas molecules on the pillars, and the filling of the gas vapour in the voids.

Axial mercury segregation in direct current operated low-pressure argon-mercury gas discharge: Part II. Model

International Nuclear Information System (INIS)

Gielen, John W A M; Groot, Simon de; Dijk, Jan van; Mullen, Joost J A M van der

2004-01-01

In a previous paper we had presented experimental results on mercury segregation due to cataphoresis in direct current operated low-pressure argon-mercury gas discharges. In this paper, we present our model to describe cataphoretic segregation in argon (or another noble gas)-mercury discharges. The model is based on the balance equations for mass and momentum and includes electrophoresis effects of electrons on mercury. Good agreement is found between the experimental results and model calculations. The model confirms our experimental observation that the mercury vapour pressure gradient depends on the local mercury vapour pressure. Furthermore, the model predicts the reversal of the direction of the transport of mercury under certain conditions (the phenomenon known as retrograde cataphoresis)

Intrinsic stress of bismuth oxide thin films: effect of vapour chopping and air ageing

International Nuclear Information System (INIS)

Patil, R B; Puri, R K; Puri, V

2008-01-01

Bismuth oxide thin films of thickness 1000 A 0 have been prepared by thermal oxidation (in air) of vacuum evaporated bismuth thin films (on glass substrate) at different oxidation temperatures and duration. Both the vapour chopped and nonchopped bismuth oxide thin films showed polycrystalline and polymorphic structure. The monoclinic bismuth oxide was found to be predominant in both the cases. The effect of vapour chopping and air exposure for 40 days on the intrinsic stress of bismuth oxide thin films has been studied. The vapour chopped films showed low (3.92 - 4.80 x 10 9 N/m 2 ) intrinsic stress than those of nonchopped bismuth oxide thin films (5.77 - 6.74 x 10 9 N/m 2 ). Intrinsic stress was found to increase due to air ageing. The effect of air ageing on the vapour chopped films was found low. The vapour chopped films showed higher packing density. Higher the packing density, lower the film will age. The process of chopping vapour flow creates films with less inhomogenety i.e. a low concentration of flaws and non-planar defects which results in lower intrinsic stress

Development of a custom on-line ultrasonic vapour analyzer and flow meter for the ATLAS inner detector, with application to Cherenkov and gaseous charged particle detectors

Science.gov (United States)

Alhroob, M.; Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Bozza, G.; Crespo-Lopez, O.; Degeorge, C.; Deterre, C.; DiGirolamo, B.; Doubek, M.; Favre, G.; Godlewski, J.; Hallewell, G.; Hasib, A.; Katunin, S.; Langevin, N.; Lombard, D.; Mathieu, M.; McMahon, S.; Nagai, K.; O'Rourke, A.; Pearson, B.; Robinson, D.; Rossi, C.; Rozanov, A.; Strauss, M.; Vacek, V.; Zwalinski, L.

2015-03-01

Precision sound velocity measurements can simultaneously determine binary gas composition and flow. We have developed an analyzer with custom microcontroller-based electronics, currently used in the ATLAS Detector Control System, with numerous potential applications. Three instruments monitor C3F8 and CO2 coolant leak rates into the nitrogen envelopes of the ATLAS silicon microstrip and Pixel detectors. Two further instruments will aid operation of the new thermosiphon coolant recirculator: one of these will monitor air leaks into the low pressure condenser while the other will measure return vapour flow along with C3F8/C2F6 blend composition, should blend operation be necessary to protect the ATLAS silicon tracker under increasing LHC luminosity. We describe these instruments and their electronics.

Modern gas-based temperature and pressure measurements

CERN Document Server

Pavese, Franco

2013-01-01

This 2nd edition volume of Modern Gas-Based Temperature and Pressure Measurements follows the first publication in 1992. It collects a much larger set of information, reference data, and bibliography in temperature and pressure metrology of gaseous substances, including the physical-chemical issues related to gaseous substances. The book provides solutions to practical applications where gases are used in different thermodynamic conditions. Modern Gas-Based Temperature and Pressure Measurements, 2nd edition is the only comprehensive survey of methods for pressure measurement in gaseous media used in the medium-to-low pressure range closely connected with thermometry. It assembles current information on thermometry and manometry that involve the use of gaseous substances which are likely to be valid methods for the future. As such, it is an important resource for the researcher. This edition is updated through the very latest scientific and technical developments of gas-based temperature and pressure measurem...

On output measurements via radiation pressure

DEFF Research Database (Denmark)

Leeman, S.; Healey, A.J.; Forsberg, F.

1990-01-01

It is shown, by simple physical argument, that measurements of intensity with a radiation pressure balance should not agree with those based on calorimetric techniques. The conclusion is ultimately a consequence of the circumstance that radiation pressure measurements relate to wave momentum, while...... calorimetric methods relate to wave energy. Measurements with some typical ultrasound fields are performed with a novel type of hydrophone, and these allow an estimate to be made of the magnitude of the discrepancy to be expected between the two types of output measurement in a typical case....

Boiling point measurements on liquid UO2

International Nuclear Information System (INIS)

Bober, M.; Singer, J.; Trapp, M.

1986-01-01

In analogy to the classic boiling point method, a quasi-stationary millisecond laser-heating technique was applied to measure the saturated-vapour pressure curve of liquid UO 2 in the temperature range of 3500 to 4500 K. The result is represented by log p(MPa) 5.049 -23042/T(K) according to an average heat of vaporization of 441 kJ/mol and a normal boiling point of 3808 K. Besides, spectral emissivities of liquid UO 2 were measured at the pyrometer wavelengths of 752 and 1064 nm. (author)

Evaluation of blast wave damage from very large unconfined vapour cloud explosions

International Nuclear Information System (INIS)

Munday, G.

1975-01-01

A mathematical model is described for estimating the damage potential from unconfined vapour cloud explosions. An attempt has been made to cover the salient details of the explosive phenomenon including finite flame accelerations and finite vapour cloud sizes. The model has been evaluated against two industrial incidents and the results extrapolated to large-volume vapour clouds. The authors conclude, on the evidence of this model, that great care must be taken in the evaluation of the explosion hazard from the probable occurrence of very large unconfined explosions even at distances in excess of 1 km from the centre of initiation. (author)

The mechanical vapour compression process applied to seawater desalination

International Nuclear Information System (INIS)

Murat, F.; Tabourier, B.

1984-01-01

The authors present the mechanical vapour compression process applied to sea water desalination. As an example, the paper presents the largest unit so far constructed by SIDEM using this process : a 1,500 m3/day unit installed in the Nuclear Power Plant of Flamanville in France which supplies a high quality process water to that plant. The authors outline the advantages of this process and present also the serie of mechanical vapour compression unit that SIDEM has developed in a size range in between 25 m3/day and 2,500 m3/day

Desalination using spray tower and vapour compression refrigeration system

International Nuclear Information System (INIS)

Sathish Kumar, S.; Mani, A.

2006-01-01

A desalination system using a spray tower and Vapour Compression Refrigeration (VCR) system is proposed for obtaining fresh water from brackish water. In the spray tower, simultaneous heat and mass transfer take place between the brackish water and air, which results in the evaporation of the brackish water and humidification of the air. Fresh water is obtained from the humidified air by condensing the water vapour using a VCR system. Parametric studies were carried out to study the effect of various operational parameters on the fresh water production rate. (author)

Influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces

International Nuclear Information System (INIS)

Bresme, Fernando; Gonzalez-Melchor, Minerva; Alejandre, Jose

2005-01-01

The influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces is investigated using molecular dynamics simulations of the soft primitive model. Ion size asymmetry results in charge separation at the liquid-vapour interface and therefore in a local violation of the electroneutrality condition. For moderate size asymmetries the electrostatic potential at the interface can reach values of the order of 0.1 V. Size asymmetry plays a very important role in determining ion adsorption at the liquid-vapour interface of ionic mixtures. The interfacial adsorption of the bigger component results in an increase of the electrostatic potential, and a reduction of the interfacial surface tension. Our results show that ionic mixtures provide a very efficient way to tune the electrostatics and surface properties of ionic liquid-vapour interfaces

Influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces

Energy Technology Data Exchange (ETDEWEB)

Bresme, Fernando [Department of Chemistry, Imperial College London, London SW7 2AZ (United Kingdom); Gonzalez-Melchor, Minerva [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco 186, Colonia Vicentina, 09340 Mexico D.F. (Mexico); Alejandre, Jose [Departamento de QuImica, Universidad Autonoma Metropolitana-Iztapalapa, Avenida San Rafael Atlixco 186, Colonia Vicentina, 09340 Mexico D.F. (Mexico)

2005-11-16

The influence of ion size asymmetry on the properties of ionic liquid-vapour interfaces is investigated using molecular dynamics simulations of the soft primitive model. Ion size asymmetry results in charge separation at the liquid-vapour interface and therefore in a local violation of the electroneutrality condition. For moderate size asymmetries the electrostatic potential at the interface can reach values of the order of 0.1 V. Size asymmetry plays a very important role in determining ion adsorption at the liquid-vapour interface of ionic mixtures. The interfacial adsorption of the bigger component results in an increase of the electrostatic potential, and a reduction of the interfacial surface tension. Our results show that ionic mixtures provide a very efficient way to tune the electrostatics and surface properties of ionic liquid-vapour interfaces.

A sensor of alcohol vapours based on thin polyaniline base film and quartz crystal microbalance.

Science.gov (United States)

Ayad, Mohamad M; El-Hefnawey, Gad; Torad, Nagy L

2009-08-30

Thin films of polyaniline base, emeraldine base (EB), coating on the quartz crystal microbalance (QCM) electrode were used as a sensitive layer for the detection of a number of primary aliphatic alcohols such as ethanol, methanol, 2-propanol and 1-propanol vapours. The frequency shifts (Deltaf) of the QCM were increased due to the vapour adsorption into the EB film. Deltaf were found to be linearly correlated with the concentrations of alcohols vapour in part per million (ppm). The sensitivity of the sensor was found to be governed by the chemical structure of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusions of different alcohols vapour were studied and the diffusion coefficients (D) were calculated. It is concluded that the diffusion of the vapours into the EB film follows Fickian kinetics.

Dislocations limited electronic transport in hydride vapour phase epitaxy grown GaN templates: A word of caution for the epitaxial growers

Energy Technology Data Exchange (ETDEWEB)

Chatterjee, Abhishek, E-mail: cabhishek@rrcat.gov.in; Khamari, Shailesh K.; Kumar, R.; Dixit, V. K.; Oak, S. M.; Sharma, T. K., E-mail: tarun@rrcat.gov.in [Semiconductor Physics and Devices Laboratory, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2015-01-12

GaN templates grown by hydride vapour phase epitaxy (HVPE) and metal organic vapour phase epitaxy (MOVPE) techniques are compared through electronic transport measurements. Carrier concentration measured by Hall technique is about two orders larger than the values estimated by capacitance voltage method for HVPE templates. It is learnt that there exists a critical thickness of HVPE templates below which the transport properties of epitaxial layers grown on top of them are going to be severely limited by the density of charged dislocations lying at layer-substrate interface. On the contrary MOVPE grown templates are found to be free from such limitations.

[Contemporary possibilities of intraocular pressure measurement].

Science.gov (United States)

Hornová, J; Baxant, A

2013-10-01

Authors introduced current possibilities of measuring intraocular pressure (IOP). A list of available methods of monitoring IOP is published; contact measurement method IOP directly on the cornea, but also over upper lid, methodology of minimal contact and non-contact measurement. Following contact methods are described; former measurements of IOP by impression Schiotz tonometer and the current methodology applanation. So far as the gold standard measurement Goldmann applanation tonometer (GAT) is considered, another methodology with applanation measurements are compared: Pascal dynamic contoured tonometer (DCT ), BioResonator - resonant applanation tonometer (ART ), digital applanation tonometer Tonopen and last hit: continuous measurement of IOP by Sensimed Triggerfish. Orientation and rapid assessment is palpation pressure control over the lid and measuring by tonometer Diaton. Rebound tonometer (RBT) iCare belongs to measurements with minimal contact, no need anesthetic drops and fluorescein, therefore a self - home version of IOP measurements (Icare ONE) is developed. Non-contact measurement of IOP by different pneumotonometers is popular for screening assessment of IOP. Reichert Ocular Response Analyzer (ORA) is a non-contact applanation IOP measurement and reveals additional properties of the cornea. In the discussion of a range methodology is evaluated, the experience of other authors and their own experience is compared. For monitoring of patients is necessary to select the most suitable methodology, measure repeatedly and accurately to allow long-term monitoring of intraocular pressure.

Measurement of pressure pulsations in Francis turbines

Energy Technology Data Exchange (ETDEWEB)

Kobro, Einar

2010-11-15

The work presented in this thesis involves preparation and execution of measurements on Francis runners. The measurements were performed by means of onboard measuring equipment both in model runners and full-scale prototype runners. Also, analysis of the measured data, and the discussion of the results, is presented. The measurements resulted in large data sets. These data sets were used by the author to investigate the dynamic pressure and strain in the runners. The results of the analysis can be used as input in future turbine design. Andritz Hydro AG has used the data for verification of their numerical simulation tools. In connection with the refurbishment of Tokke power plant, two model runners were made available for onboard pressure measurements. To investigate the dynamic pressure in these runners, methods for integration of pressure transducers in the runner blades needed to be developed. After initial difficulties during the preparation, successful measurements were obtained from both model runners. At Tokke power plant, both the original and replacement runners were made accessible for onboard pressure and strain gauge measurements. On the original Kvaerner Brug AS runner, the test was prepared and performed by the author. This test failed, due to water intrusion in the logging chain. The second test was performed on the Andritz Hydro AG replacement runner. This test was prepared and performed by the author in close cooperation with Andritz Hydro AG, and the results were successful. The analysis results from both model and prototype runners show that the wake leaving the guide vanes is the most severe source of dynamic pressure in the runner. The draft tube vortex rope pulsation propagates upstream the runner, but does not appear as a significant frequency in the runner strain measurements. (Author)

Context-aware patient guidance during blood pressure self-measurement

DEFF Research Database (Denmark)

Sandager, Puk; Lindahl, Camilla; Schlütter, Jacob Mørup

2013-01-01

The importance of accurate measurement of blood pressure in the screening and management of hypertension during pregnancy is well established. Blood pressure levels can be measured manually by healthcare staff or by using a blood pressure self-measurement device, either at home or in the clinic...... the blood pressure self-measurement process. Preliminary results indicate that such active and context-aware guidance leads to more reliable measurements by inhibiting non-adherent patient behavior...

The role of water-vapour photodissociation on the formation of a deep minimum in mesopause ozone

Directory of Open Access Journals (Sweden)

I. M. Vardavas

1998-02-01

Full Text Available A one-dimensional atmospheric photochemical model with an altitude grid of about 1.5 km was used to examine the structure of the global mean vertical ozone profile and its night-time-to-daytime variation in the upper atmosphere. Two distinct ozone layers are predicted, separated by a sharp drop in the ozone concentration near the mesopause. This naturally occurring mesopause ozone deep minimum is primarily produced by the rapid increase in the destruction of water vapour, and hence increase in HOx, at altitudes between 80 and 85 km, a region where water-vapour photodissociation by ultraviolet radiation of the solar Lyman-alpha line is significant, and where the supply of water vapour is maintained by methane oxidation even for very dry conditions at the tropospheric-stratospheric exchange region. The model indicates that the depth of the mesopause ozone minimum is limited by the efficiency with which inactive molecular hydrogen is produced, either by the conversion of atomic hydrogen to molecular hydrogen via one of the reaction channels of H with HO2, or by Lyman-alpha photodissociation of water vapour via the channel that leads to the production of molecular hydrogen. The ozone concentration rapidly recovers above 85 km due to the rapid increase in O produced by the photodissociation of O2 by absorption of ultraviolet solar radiation in the Schumann-Runge bands and continuum. Above 90 km, there is a decrease in ozone due to photolysis as the production of ozone through the three-body recombination of O2 and O becomes slower with decreasing pressure. The model also predicts two peaks in the night-time/daytime ozone ratio, one near 75 km and the other near 110 km, plus a strong peak in the night-time/daytime ratio of OH near 110 km. Recent observational evidence supports the predictions of the model.Key words. Atmospheric composition and structure · Middle atmosphere · Thermosphere · Transmission and scattering of radiation

Palpatory method of measuring diastolic blood pressure

Directory of Open Access Journals (Sweden)

Dinesh Sahu

2010-01-01

Conclusion: The palpatory method would be very useful where frequent blood pressure measurement are being done manually like in wards, in busy OPD, patient on treadmill and also whenever stethoscope is not available. The blood pressure can be measured in noisy environment too.

Venera 15: Water vapour in the middle atmosphere of Venus

Science.gov (United States)

Ignatiev, N. I.; Moroz, V. I.; Zasova, L. V.; Khatuntsev, I. V.

1999-01-01

In 1983, spectra of Venus in the region of 6-40 μm were measured by means of the Fourier Spectrometer aboard the Venera 15 orbiter. It covered local solar times from 4 a.m. to 10 a.m. and from 4 p.m. to 10 p.m. in the latitude range from -65° up to 87°. The results of an extended processing and analysis of these data are presented. Time and spatial variations of the water vapour were found. Most of the measurements fall in the range of 5-15 ppm, which is close to the early results. The effective altitude of sounding is approximately equal to the altitude where the optical depth τ = 1. Two latitude regions can be distinguished: (A) 20° 60°, which are characterised by different altitudes of the level of τ = 1: 62 and 55 km respectively. Mean mixing ratios near this level in the two regions are almost the same, but the partial pressures and mass densities in region (B) are 2-4 times greater than those in region (A). In region (A) a weak dayside maximum and a nightside minimum were observed. Region (B) is of inhomogeneous structure, and the retrieved mixing ratio has greater uncertainty and may probably change from the detection limit of 1 ppm up to 30 ppm. Although the retrieval of H2O mixing ratio altitude profile from the Venera 15 data appeared to be impossible, indirect indications were found that at least in region (A) the mixing ratio decreases with altitude.

Volatile times for the very first ionic liquid: understanding the vapor pressures and enthalpies of vaporization of ethylammonium nitrate.

Science.gov (United States)

Emel'yanenko, Vladimir N; Boeck, Gisela; Verevkin, Sergey P; Ludwig, Ralf

2014-09-08

A hundred years ago, Paul Walden studied ethyl ammonium nitrate (EAN), which became the first widely known ionic liquid. Although EAN has been investigated extensively, some important issues still have not been addressed; they are now tackled in this communication. By combining experimental thermogravimetric analysis with time of flight mass spectrometry (TGA-ToF-MS) and transpiration method with theoretical methods, we clarify the volatilisation of EAN from ambient to elevated temperatures. It was observed that up to 419 K, EAN evaporates as contact-ion pairs leading to very low vapour pressures of a few Pascal. Starting from 419 K, the decomposition to nitric acid and ethylamine becomes more thermodynamically favourable than proton transfer. This finding was supported by DFT calculations, which provide the free energies of all possible gas-phase species, and show that neutral molecules dominate over ion pairs above 500 K, an observation that is in nearly prefect agreement with the experimental boiling point of 513 K. This result is crucial for the ongoing practical applications of protic ionic liquids such as electrolytes for batteries and fuel cells because, in contrast to high-boiling conventional solvents, EAN exhibits no significant vapour pressure below 419 K and this property fulfils the requirements for the thermal behaviour of safe electrolytes. Overall, EAN shows the same barely measurable vapour pressures as typical aprotic ionic liquids at temperatures only 70 K lower. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

psychrometry: from partial pressures to mole fractions

African Journals Online (AJOL)

ES Obe

1980-03-01

Mar 1, 1980 ... as an ideal gas mixture. Partial pressures then become identical: to mole fractions and sets of psychometric parameters result from rather elementary thermodynamic relations. Search for more accurate data has long led to the realization that neither dry air nor pure water vapour behaves like an ideal gas,.

Lidar observations of low-level wind reversals over the Gulf of Lion and characterization of their impact on the water vapour variability

Science.gov (United States)

Di Girolamo, Paolo; Flamant, Cyrille; Cacciani, Marco; Summa, Donato; Stelitano, Dario; Richard, Evelyne; Ducrocq, Véronique; Fourrie, Nadia; Said, Frédérique

2017-02-01

Water vapour measurements from a ground-based Raman lidar and an airborne differential absorption lidar, complemented by high resolution numerical simulations from two mesoscale models (Arome-WMED and MESO-NH), are considered to investigate transition events from Mistral/Tramontane to southerly marine flow taking place over the Gulf of Lion in Southern France in the time frame September-October 2012, during the Hydrological Cycle in the Mediterranean Experiment (HyMeX) Special Observation Period 1 (SOP1). Low-level wind reversals associated with these transitions are found to have a strong impact on water vapour transport, leading to a large variability of the water vapour vertical and horizontal distribution. The high spatial and temporal resolution of the lidar data allow to monitor the time evolution of the three-dimensional water vapour field during these transitions from predominantly northerly Mistral/Tramontane flow to a predominantly southerly flow, allowing to identify the quite sharp separation between these flows, which is also quite well captured by the mesoscale models.

Pressure History Measurement in a Microwave Beaming Thruster

International Nuclear Information System (INIS)

Oda, Yasuhisa; Ushio, Masato; Komurasaki, Kimiya; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi

2006-01-01

In a microwave beaming thruster with a 1-dimensional nozzle, plasma and shock wave propagates in the nozzle absorbing microwave power. In this study, pressure histories in the thruster are measured using pressure gauges. Measured pressure history at the thruster wall shows constant pressure during plasma propagation in the nozzle. The result of measurement of the propagating velocities of shock wave and plasma shows that both propagate in the same velocity. These result shows that thrust producing model of analogy of pulse detonation engine is successful for the 1D thruster

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)

Behaviour of carbon dioxide and water vapour flux densities from a disturbed raised peat bog

NARCIS (Netherlands)

Nieveen, J.P.; Jacobs, A.F.G.

2002-01-01

Measurements of carbon dioxide and water vapour flux densities were carried out for a disturbed raised peat bog in the north of the Netherlands during an 18 month continuous experiment. Tussock grass (sp. Molinea caerulae) mainly dominated the vegetation of the bog area. The maximum leaf area index

Water vapour in the middle atmosphere of Venus:. An improved treatment of the Venera 15 ir spectra

Science.gov (United States)

Ignatiev, N. i.; Moroz, V. i.; Zasova, L. V.; Khatuntsev, I. v.

1999-08-01

In 1983, spectra of Venus in the region of 6-40 μm were measured by means of the Fourier Spectrometer aboard the Venera 15 orbiter. It covered local solar times from 4 am to 10 am and from 4 pm to 10 pm in the latitude range from 65°S up to 87°N. The results of an extended processing and analysis of these data are presented. Time and spatial variations of the water vapour were found. Most of the measurements fall in the range of 5-15 ppm, which is close to earlier results. The effective altitude of sounding is approximately equal to the altitude where the optical depth τ = 1. In the northern hemisphere, which was mainly covered by the measurements, two latitude regions can be distinguished; (A) 20° 60°, which are characterised by different altitudes of the level of τ = 1, 62 and 55 km respectively. Mean mixing ratios near this level in the two regions are almost the same, but the partial pressures and mass densities in the region (B) are 2-4 times greater than those in region (A). In region (A) a weak maximum was detected near 10 am local solar time (17 ppm at φ = 35°) and a minimum-near 10 pm (2ppm at φ = 30°). Region (B) is of inhomogeneous structure, and the retrieved mixing ratio has greater uncertainty and may probably change from the low values up to 30 ppm. In region (A) the water vapour mass density at the level of τ = 1 is 2-4 times greater than the mean density of the water contained in aerosol particles, while in region (B) this ratio may vary in the limits 0.5-5. Although the retrieval of H2O mixing ratio altitude profile from the Venera 15 data appeared to be impossible, indirect indications were found that at least in region (A) the mixing ratio decreases with altitude.

Ethylene vinylacetate copolymer and nanographite composite as chemical vapour sensor

International Nuclear Information System (INIS)

Stepina, Santa; Sakale, Gita; Knite, Maris

2013-01-01

Polymer-nanostructured carbon composite as chemical vapour sensor is described, made by the dissolution method of a non-conductive polymer, ethylene vinylacetate copolymer, mixed with conductive nanographite particles (carbon black). Sensor exhibits relative electrical resistance change in chemical vapours, like ethanol and toluene. Since the sensor is relatively cheap, easy to fabricate, it can be used in air quality monitoring and at industries to control hazardous substance concentration in the air, for example, to protect workers from exposure to chemical spills

Effect of ionic liquids, 1-butyl-3-methyl imidazolium bromide and 1-hexyl-3-methyl imidazolium bromide on the vapour – Liquid equilibria of the aqueous D-fructose solutions at 298.15 K and atmospheric pressure using isopiestic method

International Nuclear Information System (INIS)

Zafarani-Moattar, Mohammed Taghi; Shekaari, Hemayat; Mazaher Haji Agha, Elnaz

2017-01-01

Highlights: • VLE data for aqueous fructose + [BMIm]Br or [HMIm]Br systems were measured. • Performances of different local composition models were tested in fitting VLE data. • Molal activity coefficients were calculated. • The results were discussed on basis of water, IL and sugar interactions. - Abstract: In this study, water activity measurements have been carried out by the isopiestic method for the systems (D-fructose + 1-butyl-3-methyl imidazolium bromide + H 2 O) and (D-fructose + 1-hexyl-3-methyl imidazolium bromide + H 2 O) at 298.15 K and atmospheric pressure. Vapour pressures and osmotic coefficients of the solutions have been determined from the experimental measured water activity results. The experimental water activity values were satisfactorily correlated with segment-based local composition models of the Wilson, NRTL, modified NRTL, NRF-NRTL and UNIQUAC. Then, using the parameters obtained from these models, the unsymmetrical molal activity coefficients of the D-fructose and ionic liquids in the binary and D-fructose in ternary aqueous solutions have been calculated. Furthermore, the activity coefficients of D-fructose in binary and ternary solutions were used to calculate the Gibbs energy of transfer for D-fructose from water to aqueous ionic liquid solutions. An application of McMillan-Mayer theory of solutions through virial expansion of transfer Gibbs energy was made to get pair and triplet interaction parameters and salting constant values. From the sign and magnitude of these parameters and salting constants and also from the magnitude of activity coefficients some information about solute-solute and solute-solvent interactions are obtained.

Pressure field in measurement section of wind tunnel

Directory of Open Access Journals (Sweden)

Hnidka Jakub

2017-01-01

Full Text Available The University of Defence in Brno has a new low-speed wind tunnel. In order to confirm the quality of the wind inside of the measurement section, several measurements of the dynamic pressure have been performed with the Pitot-static tube. The pressure fields are then analysed and quality of the field is evaluated. Measurement of a pressure drop on the body of a standing helicopter was conducted.

Operating experience of RAPSODIE and PHENIX relating to sodium aerosols and vapours

Energy Technology Data Exchange (ETDEWEB)

Delisle, J P; Reboul, M; Elie, X [DRNR/STRS - Centre de Cadarache, Saint-Paul-lez-Durance (France)

1977-01-01

The main difficulties resulting from sodium aerosols and vapours in the cover gas which have been encountered for 10 years in RAPSODIE and for 3 years in PHENIX are reviewed: condensation of sodium in annular spaces; plugging in primary gas pipes; plugging of filters and vapour traps. All those problems were easily overcome. (author)

Partitioning understory evapotranspiration in semi-arid ecosystems in Namibia using the isotopic composition of water vapour

Science.gov (United States)

de Blécourt, Marleen; Gaj, Marcel; Holtorf, Kim-Kirsten; Gröngröft, Alexander; Brokate, Ralph; Himmelsbach, Thomas; Eschenbach, Annette

2016-04-01

In dry environments with a sparse vegetation cover, understory evapotranspiration is a major component of the ecosystem water balance. Consequently, knowledge on the size of evapotranspiration fluxes and the driving factors is important for our understanding of the hydrological cycle. Understory evapotranspiration is made up of soil evaporation and plant transpiration. Soil evaporation can be measured directly from patches free of vegetation. However, when understory vegetation is present distinguishing between soil evaporation and plant transpiration is challenging. In this study, we aim to partition understory evapotranspiration based on an approach that combines the measurements of water-vapour fluxes using the closed chamber method with measurements of the isotopic composition of water vapour. The measurements were done in the framework of SASSCAL (Southern African Science Service Centre for Climate Change and Adaptive Land Management). The study sites were located in three different semi-arid ecosystems in Namibia: thornbush savanna, Baikiaea woodland and shrubland. At each site measurements were done under tree canopies as well as at unshaded areas between the canopies. We measured evaporation from the bare soil and evapotranspiration from patches covered with herbaceous species and shrubs using a transparent chamber connected with an infrared gas analyser (LI-8100A, LICOR Inc.). The stable isotope composition of water vapour inside the chamber and depth profiles of soil water stable isotopes were determined in-situ using a tuneable off-axis integrated cavity output spectroscope (OA-ICOS, Los Gatos Research, DLT 100). Xylem samples were extracted using the cryogenic vacuum extraction method and the isotopic composition of the extracted water was measured subsequently with a cavity-ring-down spectrometer (CRDS L2120-i, Picarro Inc.). We will present the quantified fluxes of understory evapotranspiration measured in the three different ecosystems, show the

Alcohol vapours sensor based on thin polyaniline salt film and quartz crystal microbalance.

Science.gov (United States)

Ayad, Mohamad M; Torad, Nagy L

2009-06-15

A sensor based on the quartz crystal microbalance (QCM) technique was developed for detection of a number of primary aliphatic alcohols such as ethanol, methanol, 1-propanol, and 2-propanol vapours. Detection was based on a sensitive and a thin film of polyaniline, emeraldine salt (ES), coated the QCM electrode. The frequency shifts (Delta f) of the QCM were increased due to the vapour absorption into the ES film. The values of Delta f were found to be linearly correlated with the concentrations of alcohols vapour in mg L(-1). The changes in frequency are due to the hydrophilic character of the ES and the electrostatic interaction as well as the type of the alcohol. The sensor shows a good reproducibility and reversibility. The diffusion and diffusion coefficient (D) of different alcohols vapour were determined. It was found that the sensor follows Fickian kinetics.

Persistent negative temperature response of mesophyll conductance in red raspberry (Rubus idaeus L.) leaves under both high and low vapour pressure deficits: a role for abscisic acid?

Science.gov (United States)

Qiu, Changpeng; Ethier, Gilbert; Pepin, Steeve; Dubé, Pascal; Desjardins, Yves; Gosselin, André

2017-09-01

The temperature dependence of mesophyll conductance (g m ) was measured in well-watered red raspberry (Rubus idaeus L.) plants acclimated to leaf-to-air vapour pressure deficit (VPDL) daytime differentials of contrasting amplitude, keeping a fixed diurnal leaf temperature (T leaf ) rise from 20 to 35 °C. Contrary to the great majority of g m temperature responses published to date, we found a pronounced reduction of g m with increasing T leaf irrespective of leaf chamber O 2 level and diurnal VPDL regime. Leaf hydraulic conductance was greatly enhanced during the warmer afternoon periods under both low (0.75 to 1.5 kPa) and high (0.75 to 3.5 kPa) diurnal VPDL regimes, unlike stomatal conductance (g s ), which decreased in the afternoon. Consequently, the leaf water status remained largely isohydric throughout the day, and therefore cannot be evoked to explain the diurnal decrease of g m . However, the concerted diurnal reductions of g m and g s were well correlated with increases in leaf abscisic acid (ABA) content, thus suggesting that ABA can induce a significant depression of g m under favourable leaf water status. Our results challenge the view that the temperature dependence of g m can be explained solely from dynamic leaf anatomical adjustments and/or from the known thermodynamic properties of aqueous solutions and lipid membranes.​. © 2017 John Wiley & Sons Ltd.

Blood pressure measurement in obese patients: comparison between upper arm and forearm measurements.

Science.gov (United States)

Pierin, Angela M G; Alavarce, Débora C; Gusmão, Josiane L; Halpern, Alfredo; Mion, Décio

2004-06-01

It is well known that blood pressure measurement with a standard 12-13 cm wide cuff is erroneous for large arms. To compare arm blood pressure measurements with an appropriate cuff and forearm blood pressure measurements (BPM) with a standard cuff, and both measurements by the Photopletismography (Finapres) method. One hundred and twenty-nine obese patients were studied (body mass index=40+/-7 kg/m2). The patients had three arm BPM taken by an automatic oscillometric device using an appropriate cuff and three forearm BPM with a standard cuff in the sitting position after a five-minute rest. Data were analysed by the analysis of variance. The correction values were obtained by the linear regression test. Systolic and diastolic arm BPM with an appropriate cuff were significantly lower (pforearm BPM with a standard cuff. The measurements obtained by Finapres were significantly lower (pforearm systolic and diastolic blood pressures and upper arm diastolic blood pressure. The equation to correct BPM in forearm in obese patients with arm circumference between 32-44 cm was: systolic BPM=33.2+/-0.68 x systolic forearm BPM, and diastolic BPM=25.2+0.59 x forearm diastolic BPM. This study showed that forearm blood pressure measurement overestimates the values of arm blood pressure measurement. In addition, it is possible to correct forearm BPM with an equation.

Various high precision measurements of pressure in atomic energy industry

International Nuclear Information System (INIS)

Aritomi, Masanori; Inoue, Akira; Hosoma, Takashi; Tanaka, Izumi; Gabane, Tsunemichi.

1987-01-01

As for the pressure measurement in atomic energy industry, it is mostly the measurement using differential pressure transmitters and pressure transmitters for process measurement with the general accuracy of measurement of 0.2 - 0.5 % FS/year. However, recently for the development of nuclear fusion reactors and the establishment of nuclear fuel cycle accompanying new atomic energy technology, there are the needs of the pressure measurement having higher accuracy of 0.01 % FS/year and high resolution, and quartz vibration type pressure sensors appeared. New high accuracy pressure measurement techniques were developed by the advance of data processing and the rationalization of data transmission. As the results, the measurement of the differential pressure of helium-lithium two-phase flow in the cooling system of nuclear fusion reactors, the high accuracy measuring system for the level of plutonium nitrate and other fuel substance in tanks in fuel reprocessing and conversion, the high accuracy measurement of atmospheric pressure and wind velocity in ducts, chimneys and tunnels in nuclear facilities and so on became feasible. The principle and the measured data of quartz vibration type pressure sensors are shown. (Kako, I.)

Hepatic venous pressure gradients measured by duplex ultrasound

International Nuclear Information System (INIS)

Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M.

2002-01-01

AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P -2 provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

Evaluating measurement uncertainty in fluid phase equilibrium calculations

Science.gov (United States)

van der Veen, Adriaan M. H.

2018-04-01

The evaluation of measurement uncertainty in accordance with the ‘Guide to the expression of uncertainty in measurement’ (GUM) has not yet become widespread in physical chemistry. With only the law of the propagation of uncertainty from the GUM, many of these uncertainty evaluations would be cumbersome, as models are often non-linear and require iterative calculations. The methods from GUM supplements 1 and 2 enable the propagation of uncertainties under most circumstances. Experimental data in physical chemistry are used, for example, to derive reference property data and support trade—all applications where measurement uncertainty plays an important role. This paper aims to outline how the methods for evaluating and propagating uncertainty can be applied to some specific cases with a wide impact: deriving reference data from vapour pressure data, a flash calculation, and the use of an equation-of-state to predict the properties of both phases in a vapour-liquid equilibrium. The three uncertainty evaluations demonstrate that the methods of GUM and its supplements are a versatile toolbox that enable us to evaluate the measurement uncertainty of physical chemical measurements, including the derivation of reference data, such as the equilibrium thermodynamical properties of fluids.

A vapourized Δ(9)-tetrahydrocannabinol (Δ(9)-THC) delivery system part II: comparison of behavioural effects of pulmonary versus parenteral cannabinoid exposure in rodents.

Science.gov (United States)

Manwell, Laurie A; Ford, Brittany; Matthews, Brittany A; Heipel, Heather; Mallet, Paul E

2014-01-01

Studies of the rewarding and addictive properties of cannabinoids using rodents as animal models of human behaviour often fail to replicate findings from human studies. Animal studies typically employ parenteral routes of administration, whereas humans typically smoke cannabis, thus discrepancies may be related to different pharmacokinetics of parenteral and pulmonary routes of administration. Accordingly, a novel delivery system of vapourized Δ(9)-tetrahydrocannabinol (Δ(9)-THC) was developed and assessed for its pharmacokinetic, pharmacodynamic, and behavioural effects in rodents. A commercially available vapourizer was used to assess the effects of pulmonary (vapourized) administration of Δ(9)-THC and directly compared to parenteral (intraperitoneal, IP) administration of Δ(9)-THC. Sprague-Dawley rats were exposed to pure Δ(9)-THC vapour (1, 2, 5, 10, and 20mg/pad), using a Volcano® vapourizing device (Storz and Bickel, Germany) or IP-administered Δ(9)-THC (0.1, 0.3, 0.5, 1.0mg/kg), and drug effects on locomotor activity, food and water consumption, and cross-sensitization to morphine (5mg/kg) were measured. Vapourized Δ(9)-THC significantly increased feeding during the first hour following exposure, whereas IP-administered Δ(9)-THC failed to produce a reliable increase in feeding at all doses tested. Acute administration of 10mg of vapourized Δ(9)-THC induced a short-lasting stimulation in locomotor activity compared to control in the first of four hours of testing over 7days of repeated exposure; this chronic exposure to 10mg of vapourized Δ(9)-THC did not induce behavioural sensitization to morphine. These results suggest vapourized Δ(9)-THC administration produces behavioural effects qualitatively different from those induced by IP administration in rodents. Furthermore, vapourized Δ(9)-THC delivery in rodents may produce behavioural effects more comparable to those observed in humans. We conclude that some of the conflicting findings in animal

TMX-U neutral pressure measurement diagnostic systems

International Nuclear Information System (INIS)

Pickles, W.L.; Allen, S.L.; Hill, D.N.; Hunt, A.L.; Simonen, T.C.

1984-01-01

The Tandem Mirror Experiment-Upgrade (TMX-U) has a large and complex system of Baird Alpert, magnetron, and Penning gauges, in addition to mass spectrometers (RGA), all of which measure neutral pressures in the many internal regions of TMX-U. These pressure measurements are used as part of the confinement physics data base as well as for management of the TMX-U vacuum system. Dynamic pressures are modeled by a coupled-volumes simulation code, which includes wall reflus, getter pumping, and plasma pumping

Pirani pressure sensor with distributed temperature measurement

NARCIS (Netherlands)

de Jong, B.R.; Bula, W.P.; Zalewski, D.R.; van Baar, J.J.J.; Wiegerink, Remco J.

2003-01-01

Surface micro-machined distributed Pirani pressure gauges, with designed heater-to-heat sink distances (gap-heights) of 0.35 μm and 1.10 μm, are successfully fabricated, modeled and characterized. Measurements and model response correspond within 5% of the measured value in a pressure range of 10 to

Long-term series of tropospheric water vapour amounts and HDO/H2O ratio profiles above Jungfraujoch.

Science.gov (United States)

Lejeune, B.; Mahieu, E.; Schneider, M.; Hase, F.; Servais, C.; Demoulin, P.

2012-04-01

Water vapour is a crucial climate variable involved in many processes which widely determine the energy budget of our planet. In particular, water vapour is the dominant greenhouse gas in the Earth's atmosphere and its radiative forcing is maximum in the middle and upper troposphere. Because of the extremely high variability of water vapour concentration in time and space, it is challenging for the available relevant measurement techniques to provide a consistent data set useful for trend analyses and climate studies. Schneider et al. (2006a) showed that ground-based Fourier Transform Infrared (FTIR) spectroscopy, performed from mountain observatories, allows for the detection of H2O variabilities up to the tropopause. Furthermore, the FTIR measurements allow the retrieval of HDO amounts and therefore the monitoring of HDO/H2O ratio profiles whose variations act as markers for the source and history of the atmospheric water vapour. In the framework of the MUSICA European project (Multi-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water, http://www.imk-asf.kit.edu/english/musica.php), a new approach has been developed and optimized by M. Schneider and F. Hase, using the PROFFIT algorithm, to consistently retrieve tropospheric water vapour profiles from high-resolution ground-based infrared solar spectra and so taking benefit from available long-term data sets of ground-based observations. The retrieval of the water isotopologues is performed on a logarithmic scale from 14 micro-windows located in the 2600-3100 cm-1 region. Other important features of this new retrieval strategy are: a speed dependant Voigt line shape model, a joint temperature profile retrieval and an interspecies constraint for the HDO/H2O profiles. In this contribution, we will combine the quality of the MUSICA strategy and of our observations, which are recorded on a regular basis with FTIR spectrometers, under clear-sky conditions, at the NDACC site

Comparison of Lyman-alpha and LI-COR infrared hygrometers for airborne measurement of turbulent fluctuations of water vapour

Science.gov (United States)

Lampert, Astrid; Hartmann, Jörg; Pätzold, Falk; Lobitz, Lennart; Hecker, Peter; Kohnert, Katrin; Larmanou, Eric; Serafimovich, Andrei; Sachs, Torsten

2018-05-01

To investigate if the LI-COR humidity sensor can be used as a replacement of the Lyman-alpha sensor for airborne applications, the measurement data of the Lyman-alpha and several LI-COR sensors are analysed in direct intercomparison flights on different airborne platforms. One vibration isolated closed-path and two non-isolated open-path LI-COR sensors were installed on a Dornier 128 twin engine turbo-prop aircraft. The closed-path sensor provided absolute values and fluctuations of the water vapour mixing ratio in good agreement with the Lyman-alpha. The signals of the two open-path sensors showed considerable high-frequency noise, and the absolute value of the mixing ratio was observed to drift with time in this vibrational environment. On the helicopter-towed sensor system Helipod, with very low vibration levels, the open-path LI-COR sensor agreed very well with the Lyman-alpha sensor over the entire frequency range up to 3 Hz. The results show that the LI-COR sensors are well suited for airborne measurements of humidity fluctuations, provided that a vibrationless environment is given, and this turns out to be more important than close sensor spacing.

Validation of water vapour profiles (version 13 retrieved by the IMK/IAA scientific retrieval processor based on full resolution spectra measured by MIPAS on board Envisat

Directory of Open Access Journals (Sweden)

M. Milz

2009-07-01

Full Text Available Vertical profiles of stratospheric water vapour measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS with the full resolution mode between September 2002 and March 2004 and retrieved with the IMK/IAA scientific retrieval processor were compared to a number of independent measurements in order to estimate the bias and to validate the existing precision estimates of the MIPAS data. The estimated precision for MIPAS is 5 to 10% in the stratosphere, depending on altitude, latitude, and season. The independent instruments were: the Halogen Occultation Experiment (HALOE, the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS, the Improved Limb Atmospheric Spectrometer-II (ILAS-II, the Polar Ozone and Aerosol Measurement (POAM III instrument, the Middle Atmospheric Water Vapour Radiometer (MIAWARA, the Michelson Interferometer for Passive Atmospheric Sounding, balloon-borne version (MIPAS-B, the Airborne Microwave Stratospheric Observing System (AMSOS, the Fluorescent Stratospheric Hygrometer for Balloon (FLASH-B, the NOAA frostpoint hygrometer, and the Fast In Situ Hygrometer (FISH. For the in-situ measurements and the ground based, air- and balloon borne remote sensing instruments, the measurements are restricted to central and northern Europe. The comparisons to satellite-borne instruments are predominantly at mid- to high latitudes on both hemispheres. In the stratosphere there is no clear indication of a bias in MIPAS data, because the independent measurements in some cases are drier and in some cases are moister than the MIPAS measurements. Compared to the infrared measurements of MIPAS, measurements in the ultraviolet and visible have a tendency to be high, whereas microwave measurements have a tendency to be low. The results of χ²-based precision validation are somewhat controversial among the comparison estimates. However, for comparison instruments whose error budget also includes

Using pressure square-like wave to measure the dynamic characteristics of piezoelectric pressure sensor

International Nuclear Information System (INIS)

Han, L-L; Tsung, T-T; Chen, L-C; Chang Ho; Jwo, C-S

2005-01-01

Piezoelectric pressure sensors are commonly used to measuring the dynamic characteristics in a hydraulic system. The dynamic measurements require a pressure sensor which has a high response rate. In this paper, we proposed use of a pressure square wave to excite the piezoelectric pressure sensor. Experimental frequencies are 0.5, 1.0, 1.5, and 2.0 kHz at 10, 15, 20 bar, respectively. Results show that the waveform of time-domain and frequencydomain response are quite different under above testing conditions. The higher the frequencies tested, the faster the pressure-rise speeds obtained. Similarly, the higher the testing pressure, the shorter the rise time attained

Measurement and modelling of high pressure density and interfacial tension of (gas + n-alkane) binary mixtures

International Nuclear Information System (INIS)

Pereira, Luís M.C.; Chapoy, Antonin; Burgass, Rod; Tohidi, Bahman

2016-01-01

Highlights: • (Density + IFT) measurements are performed in synthetic reservoir fluids. • Measured systems include CO_2, CH_4 and N_2 with n-decane. • Novel data are reported for temperatures up to 443 K and pressures up to 69 MPa. • Predictive models are tested in 16 (gas + n-alkane) systems. • Best modelling results are achieved with the Density Gradient Theory. - Abstract: The deployment of more efficient and economical extraction methods and processing facilities of oil and gas requires the accurate knowledge of the interfacial tension (IFT) of fluid phases in contact. In this work, the capillary constant a of binary mixtures containing n-decane and common gases such as carbon dioxide, methane and nitrogen was measured. Experimental measurements were carried at four temperatures (313, 343, 393 and 442 K) and pressures up to 69 MPa, or near the complete vaporisation of the organic phase into the gas-rich phase. To determine accurate IFT values, the capillary constants were combined with saturated phase density data measured with an Anton Paar densitometer and correlated with a model based on the Peng–Robinson 1978 equation of state (PR78 EoS). Correlated density showed an overall percentage absolute deviation (%AAD) to measured data of (0.2 to 0.5)% for the liquid phase and (1.5 to 2.5)% for the vapour phase of the studied systems and P–T conditions. The predictive capability of models to accurately describe both the temperature and pressure dependence of the saturated phase density and IFT of 16 (gas + n-alkane) binary mixtures was assessed in this work by comparison with data gathered from the literature and measured in this work. The IFT models considered include the Parachor, the Linear Gradient Theory (LGT) and the Density Gradient Theory (DGT) approaches combined with the Volume-Translated Predictive Peng–Robinson 1978 EoS (VT-PPR78 EoS). With no adjustable parameters, the VT-PPR78 EoS allowed a good description of both solubility and

Full scale measurement of wind induced pressures : 1 configuration of wind induced pressures

NARCIS (Netherlands)

Geurts, C.P.W.; Wijen, H.L.M.

1994-01-01

A research project 10 the spectral characteristics of wind induced pressures is in progress in Eindhoven. This project includes both wind tunnel and full scale measurements. Wind induced pressures are measured in full scale at the main building of Eindhoven University of Technology. This paper

Fuel reactivity and release of pollutants and alkali vapours in pressurized combustion for combined cycle power generation

Energy Technology Data Exchange (ETDEWEB)

Aho, M.; Haemaelaeinen, J.; Paakkinen, K.; Rantanen, J. [VTT Energy, Jyvaeskylae (Finland); Hernberg, R.; Haeyrinen, V.; Joutsenoja, T. [Tampere Univ. of Technology (Finland). Lab. of Plasma Technology

1996-12-01

This project forms a part of the overall Pressurized Power Coal Combustion Project Area (PPFC) which aims at an assessment of the viability and technical merits of pressurized pulverized coal combustion, in an atmosphere of recycled flue gas and oxygen in a coordinated and harmonized programme. The objective of the research at Technical Research Centre of Finland (VTT) and Tampere University of Technology (TUT) is aimed at determining the consequences of solid fuel burning in a mixture of oxygen and recycled flue gases. Combustion conditions of a pressurized entrained flow of pulverized coal and char particles in PEFR are determined with high precision. The effects of experimental parameters on the formation of nitrogen oxides (N{sub 2}O, NO and NO{sub 2}) and gaseous alkali compounds (indicated as NaX(g) and KX(g)) are studied. An effective on-line analysis method for vaporised Na and K compounds was developed. The dependency between particle temperatures and the vaporisation of Na and K was measured with three coals. The results show that alkali removal before gas turbines is always necessary with these coals if combusted in combined cycles. Pressure decreases the formation of NO and has usually no clear effect on the formation of N{sub 2}O. The order of NO/N{sub 2}O ratios correspond to fuel-O/fuel-N ratios. Increase of PO{sub 2} (oxygen concentration) of combustion gas increases the formation of NO{sub 2}. Remarkable concentrations of NO{sub 2} were often measured at high PO{sub 2} at 800-850 deg C. Therefore, NO{sub 2} should be measured from pressurized fluidized bed reactors. Some trends of the formation of NO{sub 2} with coal differ clearly from those with its parent char: N{sub 2}O formation is not strongly temperature dependent with char, and the concentrations of N{sub 2}O formed from char are much lower than those of coal. PO{sub 2} does not effect on the formation of NO from char in the studied range

Properties of low-pressure drift chambers

International Nuclear Information System (INIS)

Breskin, A.; Trautner, N.

1976-01-01

Drift chambers operated with methylal vapour or ethylene at pressures in the range of 10-110 torr are described. A systematic study of position resolution, pulse height and rise time shows that especially for ethylene they are strongly influenced by electron diffusion. Intrinsic position resolution was found to be at least as good as found at atmospheric pressure. A relative pulse height resolution of 10% was obtained with 5.5 MeV alpha-particles. A simple mathematical model which can describe the processes in the drift chamber is presented. (Auth.)

Effect of cooling tower vapours on agriculture in the environment of power plants

International Nuclear Information System (INIS)

Seemann, J.

1976-01-01

The effect of cooling tower vapours according to investigations made so far are mainly noticeable regarding solar radiation, and this is practically merely in the immediate neighbourhood of the power plant. The effective influence on photosynthesis should be hardly detectable even in this limited area around the power plant. The effect on the temperature is minimum, the influence on the relative moisture is so small that it lies within the margin of error of measuring, with the exception of the few cases in which the vapours are pressed down to the ground. One need not reckon with an increased fungoid growth and bad drying conditions. Rainfall could be additionally increased if the weather situation is likely to rain or if it is raining anyway. Regarding fog frequency, one may assume that there might be a certain increase in fog. So far no cases are known in which fog would occur where there is no general tendency for fog formation. (orig.) [de

Procedure for the reversible confinement of gases or vapours in a natural or synthetic zeolite

International Nuclear Information System (INIS)

1980-01-01

The zeolite is treated with silane at a temperature of 100-140 0 C to silanise it in the H-form. This narrows the pores in the zeolite and the grains bind together creating cavities. The silanised zeolite and the material to be confined are brought into contact at high pressure, for example at an excess pressure of 0.5 atm. Contact is continued until the required quantity of gas or vapour has been adsorbed by the zeolite. Under the same high pressure water is added to the system which causes further narrowing of the pores. Preferably the process of silanising and treating with water is then repeated one or more times to close the pores and ensure confinement. The process is reversed by heating the product above 300 0 C. The bonds formed by silanising are then broken and the confined material is liberated. This process has applications in the confinement of valuable gases such as enriched isotopes, and of dangerous gases such as radioactive waste gases. (Th.W.P.)

Investigation of Raman bands vapour of contours of trichloroethylene at high pressure

International Nuclear Information System (INIS)

Zaleskaya, G.A.; Ikramov, M.; Shukurov, T.

1989-01-01

Investigation of high-pressure extraneous gas on contour comb. band, spreading trichloroethylene steams are in given article. Increasing of extraneous gas pressure brings to decreasing free molecule circling time is shown

Preparation of carbon nanotubes with different morphology by microwave plasma enhanced chemical vapour deposition

Energy Technology Data Exchange (ETDEWEB)

Duraia, El-Shazly M. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan); Mansurov, Zulkhair [Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Tokmoldin, S.Zh. [Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan)

2010-04-15

In this work we present a part of our results about the preparation of carbon nanotube with different morphologies by using microwave plasma enhanced chemical vapour deposition MPECVD. Well aligned, curly, carbon nanosheets, coiled carbon sheets and carbon microcoils have been prepared. We have investigated the effect of the different growth condition parameters such as the growth temperature, pressure and the hydrogen to methane flow rate ratio on the morphology of the carbon nanotubes. The results showed that there is a great dependence of the morphology of carbon nanotubes on these parameters. The yield of the carbon microcoils was high when the growth temperature was 700 C. There is a linear relation between the growth rate and the methane to hydrogen ratio. The effect of the gas pressure on the CNTs was also studied. Our samples were investigated by scanning electron microscope and Raman spectroscopy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

The Effect of Sloshing on a Tank Pressure Build-up Unit

OpenAIRE

Banne, Håvard Bolstad

2017-01-01

This thesis work has aimed to identify how sloshing will affect a liquefied natural gas (LNG) fuel tank. The physical nature of LNG means it needs to be kept cooled and pressurized in order to remain in a liquid state. By implementing a pressure build-up unit (PBU) it is possible to pressurize the tank vaporizing the tank’s contents, for the vapour then to return to tank in a loop, building pressure in the process. A tank pressure build-up unit has been built in the laboratory ...

Blood pressure measurement: one arm or both arm?

Science.gov (United States)

Kulkarni, Prasad K; Shekhar, Susheela; Reddy, B N; Nirmala, B C

2011-09-01

Guidelines for measuring blood pressure includes measurement of blood pressure on both arms but it is often ignored. Our case report aims at highlighting the need follow the guidelines. A 60 year old 59 kg weighing male asymptomatic patient without any comobidities was posted for bilateral inguinal hernia repair. The interarm blood pressure difference was discovered incidentally during his preanaesthetic evalution. On further evaluation patient was found to be having subclavian stenosis on left side which was asymptomatic. Intraoperative and post operative period was uneventful. Blood pressure measurement should be done in accordance with the stipulated guidelines. Inter arm blood pressure difference should be noted in all patients as not only for diagnosis and treatment of hypertension but also as a tool to diagnose asymptomatic peripheral vascular disesase.

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

Science.gov (United States)

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; Croteau, Philip; Canagaratna, Manjula R.; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose L.

2017-08-01

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH4)2SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ˜ 200-800 °C) on the detected fragments, CE and size distributions are investigated. A Tv of 500-550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH4NO3) and comparable to or higher than the SV for less-volatile species (e.g. (NH4)2SO4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the

Modelling of gas-metal arc welding taking into account metal vapour

Energy Technology Data Exchange (ETDEWEB)