Study of vapour pressure of lithium nitrate solutions in ethanol

Energy Technology Data Exchange (ETDEWEB)

Verevkin, Sergey [Abteilung Physikalische Chemie, Institut fuer Chemie, Universitaet Rostock, Hermannstrasse, 14, D-18055 Rostock (Germany); Safarov, Javid [Heat and Refrigeration Techniques, Azerbaijan Technical University, H. Javid Avn. 25, AZ1073 Baku (Azerbaijan)]. E-mail: javids@azdata.net; Bich, Eckard [Abteilung Physikalische Chemie, Institut fuer Chemie, Universitaet Rostock, Hermannstrasse, 14, D-18055 Rostock (Germany); Hassel, Egon [Lehrstuhl fuer Technische Thermodynamik, Fakultaet Maschinenbau und Schiffstechnik, Universitaet Rostock, Albert-Einstein-Str. 2, D-18059 Rostock (Germany); Heintz, Andreas [Abteilung Physikalische Chemie, Institut fuer Chemie, Universitaet Rostock, Hermannstrasse, 14, D-18055 Rostock (Germany)

2006-05-15

Vapour pressure p of (LiNO{sub 3} + C{sub 2}H{sub 5}OH) solutions at T = (298.15 to 323.15) K were measured, osmotic, activity coefficients ({phi}, {gamma}) and activity of solvent a {sub s} have been evaluated. The experiments were carried out in the molality range m = (0.19125 to 2.21552) mol . kg{sup -1}. The Antoine equation was used for the empirical description of the experimental vapour pressure results and the (Pitzer + Mayorga) model with inclusion of Archer's ionic strength dependence of the third virial coefficient for the calculated osmotic coefficients were used. The parameters of the Archer for the extended Pitzer model was used for the evaluation of activity coefficients.

Vapour pressure and enthalpy of vaporization of aliphatic poly-amines

International Nuclear Information System (INIS)

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

2010-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Thermodynamic properties of the liquid Hg-Tl alloys determined from vapour pressure measurements

Directory of Open Access Journals (Sweden)

Gierlotka W.

2002-01-01

Full Text Available The partial vapour pressure of mercury over liquid Hg-Tl liquid solutions were determined in the temperature range from 450 to 700 K by direct vapour pressure measurements carried out with the quartz gauge. From the measured ln pHg vs. T relationships activities of mercury were determined. Using Redlich-Kister formulas logarithms of the activity coefficients were described with the following equations: From which all thermodynamic functions in the solutions can be derived.

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.

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

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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.

Thermodynamic and kinetic studies in the systems alkali chloride-zinconium (or hafnium) tetrachloride: Part I. Vapour pressure measurements over hexachloro compounds and use of vapour pressure data in fractional decomposition

International Nuclear Information System (INIS)

Ray, H.S.; Bhat, B.G.; Reddy, G.S.; Biswas, A.K.

1978-01-01

A molten tin isoteniscope has been used to measure the vapour pressures over ZrCl 4 , HfCl 4 and the hexachlore zirconates (M 2 ZrCl 6 ) and the hexachloro hafnates (M 2 HfCl 6 ) of four alkali metals (M = Na,K,Rb,Cs). The method of preparation of these compounds and the effect of small amounts of residual alkali chlorides on the their vapour pressure are discussed. The pressure-temperature plots are examined in the light of some theoretical postulates. A scheme for separation of hafnium from zirconoium by multistage fractional decomposition of the hexachlore compounds of any alkali metal is described. The scheme, which is analogous to rectification in liquid-vapour systems, employs a countercurrent flow of Zr(Hf)Cl 4 in a gas stream and a moving bed of alkali chlorides. The separation is based on the difference in the dissociation equilibrium for zirconium and hafnium compounds. Stage calculations for such a scheme and the main conclusions of a computational work are presented. (author)

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

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

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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.

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

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

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Schick, Christoph

2007-01-01

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

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.

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.

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...

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).

Measurement and correlation of vapour pressures of pyridine and thiophene with [EMIM][SCN] ionic liquid

International Nuclear Information System (INIS)

Khelassi-Sefaoui, Asma; Mutelet, Fabrice; Mokbel, Ilham; Jose, Jacques; Negadi, Latifa

2014-01-01

Highlights: • VLE of (pyridine + [EMIM][SCN]), or (thiophene + [EMIM][SCN]) binary mixtures were measured. • The investigated temperatures are 273 K to 363 K. • The PC-SAFT equation of state has been used to correlate the vapour pressures of the binary systems. - Abstract: In this work (vapour + liquid) equilibrium (VLE) measurements were performed on binary systems of the ionic liquid 1-ethyl-3-methylimidazolium thiocynate [EMIM][SCN] with thiophene or pyridine at pressures close to the atmospheric pressure using a static device at temperatures between 273 K and 363 K. Experimental data were correlated by the PC-SAFT EoS. The binary interaction parameters k ij were optimised on experimental VLE data. The results obtained for the two binary mixtures studied in this paper indicate that the PC-SAFT EoS can be used to represent systems containing ionic liquids

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 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...

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...

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...

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)

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.

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

deficit and global radiation. In the model with all factors, Species was most important, and when Species was omitted, stomatal conductance was the most important determinant for leaf injury to occur, whereas mean relative growth rate was less important. With no plant-related factors included, air vapour pressure deficit and AOT40 were of highest importance. Only in eight species was a positive relationship found between these two factors during the five days before the onset of injury, indicating increasing protection from ozone with increasing air vapour pressure deficit in some but not all species. These data show that across a range of grassland species, leaf injury caused by elevated levels of ozone is most likely to occur in species with high stomatal conductance and that protection from ozone during dry periods is species-specific and depends on a reduction in stomatal conductance due to a decrease in soil moisture potential. Protection under increased vapour pressure deficit can occur in some but not all species, depending on the relationship between stomatal conductance and air vapour pressure deficit. (author)

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

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.

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

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.

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

A simple experimental arrangement for measuring the vapour pressures and sublimation enthalpies by the Knudsen effusion method: Application to DNA and RNA bases

International Nuclear Information System (INIS)

Barros, A.L.F. de; Medina, A.; Zappa, F.; Pereira, J.M.; Bessa, E.; Martins, M.H.P.; Coelho, L.F.S.; Wolff, W.; Castro Faria, N.V. de

2006-01-01

We measured the vapour pressure of several DNA and RNA bases-uracil, adenine, guanine, thymine and cytosine-in the 300-450 K range. In each case the sample mass loss rate was measured as function of temperature with a simple setup consisting of a commercial film deposition system and a homemade oven. Afterwards vapour pressure values were extracted from these data using the Knudsen effusion method. Sublimation enthalpy values, obtained from vapour pressure data by applying the Clausius-Clapeyron equation, are in very good agreement with literature values. The results suggest that crystal-based film thickness monitors may be useful in on-line cross-section measurements, monitoring the gas target thickness. They also show the viability of using this oven for producing a biomolecular gas target

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-...

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)

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

Directory of Open Access Journals (Sweden)

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.

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.)

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

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.

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 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

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

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.

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.

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

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

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-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.

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.

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

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

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.)

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

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...

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.

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.

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.).

Hydrogen termination of CVD diamond films by high-temperature annealing at atmospheric pressure

NARCIS (Netherlands)

Seshan, V.; Ullien, D.; Castellanos-Gomez, A.; Sachdeva, S.; Murthy, D.H.K.; Savenije, T.J.; Ahmad, H.A.; Nunney, T.S.; Janssens, S.D.; Haenen, K.; Nesládek, M.; Van der Zant, H.S.J.; Sudhölter, E.J.R.; De Smet, L.C.P.M.

2013-01-01

A high-temperature procedure to hydrogenate diamond films using molecular hydrogen at atmospheric pressure was explored. Undoped and doped chemical vapour deposited (CVD) polycrystalline diamond films were treated according to our annealing method using a H2 gas flow down to ?50 ml/min (STP) at

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....

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

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

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.

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)

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 -).

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....

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

(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

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

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.

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

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.)

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.

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

Results of a photographic study of subcooled forced-convection boiling of high-pressure water and Freon-12

International Nuclear Information System (INIS)

Macbeth, R.V.; Wood, R.W.

1980-06-01

The use of a 'Freon' to model high-pressure boiling water has been employed successfully in a number of applications. A prerequisite in modelling is that a well tried and proven basis for the modelling exists. This is not entirely the situation with subcooled boiling however, since past work had tended to concentrate on bulk boiling conditions. Since many of the questions that arise in the design of subcooled boiling systems are concerned with two-phase flow structure, it was decided to place emphasis on attempting to match photographs of subcooled two-phase conditions in high-pressure water (at 55.2 and 82.7 bar) with those of Freon-12 at the corresponding pressures (8.13 and 12.75 bar). A special test-section was constructed giving visual access to a vapour forming region and to an unheated region into which vapour bubbles were drawn by the flow of subcooled liquid. The photographs obtained show that close similarity of two-phase flow structure exists in water and in Freon at corresponding conditions as determined by a previously established modelling procedure. (U.K.)

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)

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)

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.

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

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...

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

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.

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.)

High-pressure phase equilibrium data for systems with carbon dioxide, α-humulene and trans-caryophyllene

International Nuclear Information System (INIS)

Michielin, Eliane M.Z.; Rosso, Sibele R.; Franceschi, Elton; Borges, Gustavo R.; Corazza, Marcos L.; Oliveira, J. Vladimir; Ferreira, Sandra R.S.

2009-01-01

The aim of this work is to report phase equilibrium data for the binary systems (CO 2 + α-humulene) and (CO 2 + trans-caryophyllene), and for the ternary system (CO 2 + α-humulene + trans-caryophyllene). Results from literature show that α-humulene and trans-caryophyllene are the main compounds responsible for the anti-inflammatory and anti-allergic characteristics attributed to the medicinal plant Cordia verbenacea D.C., hence giving importance to the phase behaviour investigation performed in this work. Phase equilibrium experiments were performed in a high-pressure, variable-volume view cell over the temperature range of T = (303 to 343) K and pressures up to 20 MPa. (Liquid + liquid) and (vapour + liquid + liquid) equilibrium were observed at T = 303 K, while (vapour + liquid) phase transitions were verified to occur from T = (313 to 343) K, for all systems studied. Thermodynamic modelling was performed using the Peng-Robinson equation of state and the classical quadratic mixing rules, with a satisfactory agreement between experimental and calculated values

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)

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...

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....

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...

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.

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)

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.

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.

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.

High-pressure phase equilibrium data for systems with carbon dioxide, {alpha}-humulene and trans-caryophyllene

Energy Technology Data Exchange (ETDEWEB)

Michielin, Eliane M.Z.; Rosso, Sibele R [EQA/UFSC, Chemical and Food Engineering Department, Federal University of Santa Catarina, C.P. 476, CEP 88040-900, Florianopolis, SC (Brazil); Franceschi, Elton; Borges, Gustavo R; Corazza, Marcos L; Oliveira, J Vladimir [Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS, 99700-000 (Brazil); Ferreira, Sandra R.S. [EQA/UFSC, Chemical and Food Engineering Department, Federal University of Santa Catarina, C.P. 476, CEP 88040-900, Florianopolis, SC (Brazil)], E-mail: sandra@enq.ufsc.br

2009-01-15

The aim of this work is to report phase equilibrium data for the binary systems (CO{sub 2} + {alpha}-humulene) and (CO{sub 2} + trans-caryophyllene), and for the ternary system (CO{sub 2} + {alpha}-humulene + trans-caryophyllene). Results from literature show that {alpha}-humulene and trans-caryophyllene are the main compounds responsible for the anti-inflammatory and anti-allergic characteristics attributed to the medicinal plant Cordia verbenacea D.C., hence giving importance to the phase behaviour investigation performed in this work. Phase equilibrium experiments were performed in a high-pressure, variable-volume view cell over the temperature range of T = (303 to 343) K and pressures up to 20 MPa. (Liquid + liquid) and (vapour + liquid + liquid) equilibrium were observed at T = 303 K, while (vapour + liquid) phase transitions were verified to occur from T = (313 to 343) K, for all systems studied. Thermodynamic modelling was performed using the Peng-Robinson equation of state and the classical quadratic mixing rules, with a satisfactory agreement between experimental and calculated values.

Generalized method for calculation and prediction of vapour-liquid equilibria at high pressures

Energy Technology Data Exchange (ETDEWEB)

Drahos, J; Wichterle, I; Hala, E

1978-02-01

Following the approaches of K.C. Chao and J.D. Seader (see Gas Abstr. 18,24 (1962) Jan.) and B.I. Lee, J.H. Erbar, and W.C. Edmister (see Gas Abst. 29, 73-0331), the Czechoslovak Academy of Sciences developed a generalized method for prediction of vapor-liquid equilibria in hydrocarbon mixtures containing some nonhydrocarbon gases at high pressures. The method proposed is based on three equations: (1) a generalized equation of state for vapor-phase calculations; (2) a generalized expression for the pure-liquid fugacity coefficient; and (3) an activity coefficient expression based on a surface modification of the regular solution model. The equations used contain only one partially generalized binary parameter, which was evaluated from experimental K-value data. Researchers tested the proposed method by computing K-values and pressures in binary and multicomponent systems consisting of 13 hydrocarbons and 3 nonhydrocarbon gases. The results show that the method is applicable over a wide range of conditions with a degree of accuracy comparable with that of more complicated methods.

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)

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)

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.

High temperature defect equilibrium in ZnS:Cu single crystals

Energy Technology Data Exchange (ETDEWEB)

Lott, K.; Shinkarenko, S.; Tuern, L.; Nirk, T.; Oepik, A. [Department of Materials Science, Tallinn University of Technology, Tallinn (Estonia); Kallavus, U. [Centre for Materials Research, Tallinn University of Technology, Tallinn (Estonia); Gorokhova, E. [Scientific Research and Technological Institute of Optical Material Science, S. I. Vavilov State Optical Institute, All-Russia Science Center, St. Petersburg (Russian Federation); Grebennik, A.; Vishnjakov, A. [Department of Physical Chemistry, D. Mendelejev University of Chemical Technology of Russia, Moscow (Russian Federation)

2010-07-15

High temperature investigations in ZnS:Cu crystals were performed under defined conditions. High temperature electrical conductivity and copper solubility data were obtained under different component vapour pressures and under different sample temperatures. The experimental data at sulphur vapour pressure can be explained by the inclusion of abnormal site occupation i.e. by antistructural disorder. Compensating association of copper with this antistructure defect may occur. Antistructure disorder disappears with increasing of zinc vapour pressure and with increasing role of holes in bipolar conductivity. The method for solving the system of quasichemical reactions without approximation was used to model high temperature defect equilibrium. This model contains antistructure disorder and copper solubility limitation. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

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.)

Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

Energy Technology Data Exchange (ETDEWEB)

Bykovskiy, D P; Petrovskii, V N; Uspenskiy, S A [National Research Nuclear University ' MEPhI' (Russian Federation)

2015-03-31

The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study. (interaction of laser radiation with matter)

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.

Robust microscale superlubricity under high contact pressure enabled by graphene-coated microsphere

Science.gov (United States)

Liu, Shu-Wei; Wang, Hua-Ping; Xu, Qiang; Ma, Tian-Bao; Yu, Gui; Zhang, Chenhui; Geng, Dechao; Yu, Zhiwei; Zhang, Shengguang; Wang, Wenzhong; Hu, Yuan-Zhong; Wang, Hui; Luo, Jianbin

2017-02-01

Superlubricity of graphite and graphene has aroused increasing interest in recent years. Yet how to obtain a long-lasting superlubricity between graphene layers, under high applied normal load in ambient atmosphere still remains a challenge but is highly desirable. Here, we report a direct measurement of sliding friction between graphene and graphene, and graphene and hexagonal boron nitride (h-BN) under high contact pressures by employing graphene-coated microsphere (GMS) probe prepared by metal-catalyst-free chemical vapour deposition. The exceptionally low and robust friction coefficient of 0.003 is accomplished under local asperity contact pressure up to 1 GPa, at arbitrary relative surface rotation angles, which is insensitive to relative humidity up to 51% RH. This ultralow friction is attributed to the sustainable overall incommensurability due to the multi-asperity contact covered with randomly oriented graphene nanograins. This realization of microscale superlubricity can be extended to the sliding between a variety of two-dimensional (2D) layers.

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

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.

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

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 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...

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)

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.

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.

A copper bromide vapour laser with a high pulse repetition rate

International Nuclear Information System (INIS)

Shiyanov, D V; Evtushenko, Gennadii S; Sukhanov, V B; Fedorov, V F

2002-01-01

The results of an experimental study of a copper bromide vapour laser with a discharge-channel diameter above 2.5 cm and a high pump-pulse repetition rate are presented. A TGU1-1000/25 high-power tacitron used as a switch made it possible to obtain for the first time a fairly high output radiation power for pump-pulse repetition rates exceeding 200 kHz. At a maximum pump-pulse repetition rate of 250 kHz achieved in a laser tube 2.6 cm in diameter and 76 cm long, the output power was 1.5 W. The output powers of 3 and 10.5 W were reached for pump-pulse repetition rates of 200 and 100 kHz, respectively. These characteristics were obtained without circulating a buffer gas and (or) low-concentration active impurities through the active volume. (active media. lasers)

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)

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.

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...

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

Effect of water vapour absorption on hydroxyl temperatures measured from Svalbard

Directory of Open Access Journals (Sweden)

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.

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)

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)

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'

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

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.

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.

A high current metal vapour vacuum arc ion source for ion implantation studies

International Nuclear Information System (INIS)

Evans, P.J.; Noorman, J.T.; Watt, G.C.; Cohen, D.D.; Bailey, G.M.

1989-01-01

The main features of the metal vapour vacuum arc(MEVA) as an ion source are presented. The technology utilizes the plasma production capabilities of a vacuum arc cathode. Some of the ions produced in this discharge flow through the anode and the 3 extraction grids to form an extracted ion beam. The high beam current and the potential for generating broad beams, make this technology suitable for implantation of large surface areas. The composition of the vacuum arc cathode determines the particular ions obtained from the MEVA source. 3 refs., 1 tab., 2 figs

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)

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

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

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.

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

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.

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)

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.

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

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.

Experimental study of the zirconium alloy oxidation under high pressure of steam and modelling of the mechanisms

International Nuclear Information System (INIS)

Dali, Yacoub

2007-01-01

The corrosion of the cladding materials used for the fuel rods is one of the limiting factor of their lifetime in light water reactors. In this field, the aim of the nuclear industry is today to increase the time and the number of cycles and to submit the claddings in zirconium alloys to higher corrosive conditions. In this way, new alloys devoted to replace the standard Zircaloy-4, for instance Nb containing alloys, have been recently developed and licensed and show better corrosion resistance. A better understanding of the corrosion mechanisms of the zirconium alloys is necessary to predict the corrosion behaviour of these materials. In this work, the oxidation rate of model alloys of two metallurgic families has been studied in steam in a pressure range between 100 milli-bars and 100 bars. The Zircaloy type alloys contain as alloying elements oxygen and/or tin and/or iron and chromium. For the Zr-Nb family, three niobium contents have been studied, respectively 0.2, 0.4 and 1 weight percent of niobium. Our objectives were to understand the variations of the reactivity between the low pressure and the high pressure range, in quantifying the dependency of the corrosion rate with the steam pressure and the alloying element concentrations. The segregation process of the niobium at the surface has also been studied on the Zr-Nb alloys. During this work, a magnetic suspension thermo-balance has been developed and used to follow in-situ the corrosion rate at high pressure of water vapour. The oxide layers have been characterized by many techniques, macro and micro-photo-electrochemistry, XRD, FEG-SEM, XPS, HR-TEM and SIMS. For the Zircaloy type alloys, we have confirmed the major role of the intermetallic precipitates Zr(Fe,Cr) 2 on the corrosion resistance. Unlike the standard Zircaloy-4, for which the oxidation rate does not depend on the pressure of the water vapour and is thus limited by the vacancy diffusion in the oxide layer, we have shown that the rate of the

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

[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.

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.)

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.

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.

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.)

Water Vapour Propulsion Powered by a High-Power Laser-Diode

Science.gov (United States)

Minami, Y.; Uchida, S.

Most of the laser propulsion schemes now being proposed and developed assume neither power supplies nor on-board laser devices and therefore are bound to remote laser stations like a kite via a laser beam “string”. This is a fatal disadvantage for a space vehicle that flies freely though it is often said that no need of installing an energy source is an advantage of a laser propulsion scheme. The possibility of an independent laser propulsion space vehicle that carries a laser source and a power supply on board is discussed. This is mainly due to the latest development of high power laser diode (LD) technology. Both high specific impulse-low thrust mode and high thrust-low specific impulse mode can be selected by controlling the laser output by using vapour or water as a propellant. This mode change can be performed by switching between a high power continuous wave (cw), LD engine for high thrust with a low specific impulse mode and high power LD pumping Q-switched Nd:YAG laser engine for low thrust with the high specific impulse mode. This paper describes an Orbital Transfer Vehicle equipped with the above-mentioned laser engine system and fuel cell that flies to the Moon from a space platform or space hotel in Earth orbit, with cargo shipment from lunar orbit to the surface of the Moon, including the possibility of a sightseeing trip.

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.

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

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.

Formation of calcium phosphates by vapour diffusion in highly concentrated ionic micro-droplets

Energy Technology Data Exchange (ETDEWEB)

Iafisco, M. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy); Universita del Piemonte Orientale, Dipartimento di Scienze Mediche, Via Solaroli 4, 28100 Novara (Italy); Delgado-Lopez, J.M.; Gomez-Morales, J.; Hernandez-Hernandez, M.A.; Rodriguez-Ruiz, I. [Laboratorio de Estudios Cristalograficos, IACT CSIC-UGR, Edificio Lopez Neyra, Avenida del Conocimiento, s/n 18100 Armilla (Spain); Roveri, N. [Alma Mater Studiorum Universita di Bologna, Dipartimento di Chimica ' ' G. Ciamician' ' , Via Selmi 2, 40126 Bologna (Italy)

2011-08-15

In this work we have used the sitting drop vapour diffusion technique, employing the ''crystallization mushroom '' to analyze the evolution of calcium phosphate crystallization in micro-droplets containing high initial concentrations of Ca{sup 2+} and HPO{sub 4}{sup 2-}. The decomposition of NH{sub 4}HCO{sub 3} solution produces vapours of NH{sub 3} and CO{sub 2} which diffuse through the droplets containing an aqueous solution of Ca(CH{sub 3}COO){sub 2} and (NH{sub 4}){sub 2}HPO{sub 4}. The result is the increase of pH by means of the diffusion of NH{sub 3} gas and the doping of the calcium phosphate with CO{sub 3}{sup 2-} ions by means of the diffusion of CO{sub 2} gas. The pH of the crystallization process is monitored and the precipitates at different times are characterized by XRD, FTIR, TGA, SEM and TEM techniques. The slow increase of pH and the high concentration of Ca{sup 2+} and HPO{sub 4}{sup 2-} in the droplets induce the crystallization of three calcium phosphate phases: dicalcium phosphate dihydrate (DCPD, brushite), octacalcium phosphate (OCP) and carbonate-hydroxyapatite (HA). The amount of HA nanocrystals with needle-like morphology and dimensions of about 100 nm, closely resembling the inorganic phase of bones, gradually increases, with the precipitation time up to 7 days, whereas the amount of DCPD, growing along the b axis, increases up to 3 days. Then, DCDP crystals start to hydrolyze yielding OCP nanoribbons and HA nanocrystals. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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.

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.

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.

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.

High pressure studies of as grown WX2-x single crystals

International Nuclear Information System (INIS)

Solanki, G.K.; Agarwal, M.K.; Patel, Yogesh A.

2011-01-01

The structural optical and transport properties of tungsten metal dichalogenides having layered structure have been extensively studied in the last two decades. These materials shows highly anisotropic behaviour and have been receiving considerable interest for a variety of applications. Several of these layered semiconductors have attracted attention as a new class of solar cell material. We present here the results of simultaneous resistivity and thermoelectric power (TEP) measurements upto 7 GPa on single crystals of WS 2 , WS 1.9 , WSe 2 and WSe 1.9 grown using Direct Vapour Transport (DVT) technique. The observations clearly shows WS 2 and WS 1.9 are more resistive compared to other two crystals. In all samples an exponential fall of resistivity on increases in pressure upto 2.1 GPa but after 2.2 GPa the resistivity decreases substantially with increases pressure. The TEP of WSe 2 increases steadily and reaches maximum at 0.65 GPa, while for WSe 1.9 TEP increases upto pressure 0.5 GPa. In both the cases after attaining the maximum TEP, then decreases monotonically with increase in pressure. TEP of WS 2 and WS 1.9 increase upto pressure 1.1 GPa, beyond 1.1 GPa pressure in both the cases TEP decreases steadily with further increase in pressure. In all the samples, the sign of TEP is positive indicating that all of them are p-type and remain p-type with increase in pressure. The variation of thermoelectric power factor with pressure has been thoroughly studied. An analysis of the data point out that perfectly stoichiometric crystals of WSe 2 work as superior thermoelectric materials. The results have been presented and implications have been discussed. (author)

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)

Copper vapour laser development for Silva

International Nuclear Information System (INIS)

Bettinger, A.; Neu, M.; Chatelet, J.

1993-01-01

The recent developments of the components for high power Copper Vapour Laser (CVL) have been oriented towards four main goals: high quality laser beam, mainly for the CVL oscillators, increase of the extracted energy out of the amplifying stage, fully integrated and monolithic design for oscillator and amplifier, extended lifetime and high reliability. A first step of this work, which is done under contract with CILAS (Compagnie Industrielle des Lasers) led to an injection seeded oscillator and a 100 Watts amplifier; the present step concerns development of a 400 Watts class amplifier

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.

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.

An in situ vapour phase hydrothermal surface doping approach for fabrication of high performance Co3O4 electrocatalysts with an exceptionally high S-doped active surface.

Science.gov (United States)

Tan, Zhijin; Liu, Porun; Zhang, Haimin; Wang, Yun; Al-Mamun, Mohammad; Yang, Hua Gui; Wang, Dan; Tang, Zhiyong; Zhao, Huijun

2015-04-04

A facile in situ vapour phase hydrothermal (VPH) surface doping approach has been developed for fabrication of high performance S-doped Co3O4 electrocatalysts with an unprecedentedly high surface S content (>47%). The demonstrated VPH doping approach could be useful for enrichment of surface active sites for other metal oxide electrocatalysts.

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.

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.

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.

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

Energy and exergy analysis of multi-effects distillation with thermo vapour compressor (MED-TVC) desalination system

Energy Technology Data Exchange (ETDEWEB)

Saffari, A.; Sayyaadi, H. [Khaje Nasir Toosi Univ. of Technology, Tehran (Iran, Islamic Republic of). Faculty of Mechanical Engineering, Energy Division; Alishiri, M. [Fan Niroo Co., Tehran (Iran, Islamic Republic of). Desalination and Water Solutions

2008-07-01

Countries around the world have a significant need for high-quality water. The desalination industry is especially important in ensuring the supply of high-quality water, especially the countries around the Persian Gulf such as Iran. A multiple-effect distiller (MED) with thermal vapor compression (TVC) system is more attractive than other thermal systems due to its effectiveness, easier operation and maintenance, and good economics. This paper presented a heat and mass balance relation and comprehensive exergy analysis of a typical MED with a thermal vapour compression desalination system. The purpose of the study was to provide a cost-effective tool that could be applied in the design, development and optimization of thermal desalination plants. The paper discussed the energy simulation, with particular reference to the temperatures for each effect; the condenser, gain output ratio, distillate production rate, brine outlet and feed water rates for each effect; steam consumption; coolant sea water and total sea water inlet rate; pressure distribution in the evaporators; and the entertained vapour rate at TVC. Exergy analysis revealed that the steam ejector and evaporators are the main sources of exergy destruction. It was also shown that lowering the temperature difference can minimize exergy losses. 21 refs., 4 tabs., 16 figs.

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.

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)

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 ...

Sorbent Film-Coated Passive Samplers for Explosives Vapour Detection Part A: Materials Optimisation and Integration with Analytical Technologies.

Science.gov (United States)

McEneff, Gillian L; Murphy, Bronagh; Webb, Tony; Wood, Dan; Irlam, Rachel; Mills, Jim; Green, David; Barron, Leon P

2018-04-11

A new thin-film passive sampler is presented as a low resource dependent and discrete continuous monitoring solution for explosives-related vapours. Using 15 mid-high vapour pressure explosives-related compounds as probes, combinations of four thermally stable substrates and six film-based sorbents were evaluated. Meta-aramid and phenylene oxide-based materials showed the best recoveries from small voids (~70%). Analysis was performed using liquid chromatography-high resolution accurate mass spectrometry which also enabled tentative identification of new targets from the acquired data. Preliminary uptake kinetics experiments revealed plateau concentrations on the device were reached between 3-5 days. Compounds used in improvised explosive devices, such as triacetone triperoxide, were detected within 1 hour and were stably retained by the sampler for up to 7 days. Sampler performance was consistent for 22 months after manufacture. Lastly, its direct integration with currently in-service explosives screening equipment including ion mobility spectrometry and thermal desorption mass spectrometry is presented. Following exposure to several open environments and targeted interferences, sampler performance was subsequently assessed and potential interferences identified. High-security building and area monitoring for concealed explosives using such cost-effective and discrete passive samplers can add extra assurance to search routines while minimising any additional burden on personnel or everyday site operation.

High Blood Pressure

Science.gov (United States)

... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

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.)

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.

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

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).

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

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 Dome for High-Pressure Electrolyzer

Science.gov (United States)

Norman, Timothy; Schmitt, Edwin

2012-01-01

A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

Preparation of hydrosol suspensions of elemental and core–shell nanoparticles by co-deposition with water vapour from the gas-phase in ultra-high vacuum conditions

International Nuclear Information System (INIS)

Binns, Chris; Prieto, Pilar; Baker, Stephen; Howes, Paul; Dondi, Ruggero; Burley, Glenn; Lari, Leonardo; Kröger, Roland; Pratt, Andrew; Aktas, Sitki; Mellon, John K.

2012-01-01

We report a new method to produce liquid suspensions of nanoparticles by co-deposition with water vapour from the gas-phase in ultra-high vacuum (UHV) conditions. The water is injected from outside the vacuum as a molecular beam onto a substrate maintained at 77 K and forms an ice layer with a UHV vapour pressure. Molecular dynamics simulations confirm that the nanoparticles are soft-landed close to the surface of the growing ice layer. We show that the un-agglomerated size distribution within the liquid is similar to the gas-phase size distribution and demonstrate that the inclusion of surfactants in the injected water prevents agglomeration. The method allows the flexibility and tight size control available with gas-phase production methods to be applied to making nanoparticle suspensions with any desired properties. This is important for practical applications, especially in medicine. We have extended the method to include core–shell nanoparticles, in which there is flexible control over the core size and shell thickness and free choice of the material in either. Here, we report the production of suspensions of Cu, Ag and Au elemental nanoparticles and Fe-Au and Fe-Fe-oxide core–shell nanoparticles with diameters in the range 5–15 nm. We demonstrate the power of the method in practical applications in the case of Fe-Fe-oxide nanoparticles, which have a specific absorption rate of an applied oscillating magnetic field that is significantly higher than available Fe-oxide nanoparticle suspensions and the highest yet reported. These will thus have a very high-performance in the treatment of tumours by magnetic nanoparticle hyperthermia.

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.

Development, production, and application of sealed-off copper and gold vapour lasers

International Nuclear Information System (INIS)

Lyabin, Nikolai A; Chursin, A D; Ugol'nikov, S A; Koroleva, M E; Kazaryan, M A

2001-01-01

An analysis is made of the current state of the art of scientific and engineering advances in the field of repetitively pulsed self-heating metal vapour (copper and gold) lasers based on industrial, sealed-off, high-temperature, metalceramic and metal-glass active elements. The major applications of these lasers are discussed. The energy, spatial, and time characteristics of the lasers and their dependence on the parameters and construction of the laser active elements (tubes) and optical resonators are considered. The ways for the development of new high-power industrial laser active elements with a high efficiency (1 - 2%) and a service life of 500 - 1000 h are analysed. An average output power of 80 W was realised with a laser tube 150 cm in length and 32 mm in diameter. When the pumping efficiency is improved by raising the voltage to 30 - 35 kV, this system in a copper vapour laser will allow an output power of 100 W to be obtained with one active element. The characteristics of industrial versions of metal vapour lasers manufactured in different countries are compared and discussed. (invited paper)

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

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.

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)

Distribution of tritium in water vapour and precipitation around Wolsung nuclear power plant.

Science.gov (United States)

Chae, Jung-Seok; Lee, Sang-Kuk; Kim, Yongjae; Lee, Jung-Min; Cho, Heung-Joon; Cho, Yong-Woo; Yun, Ju-Yong

2011-07-01

The distribution of tritium in water vapour and precipitation with discharge of tritiated water vapour and meteorological factors was studied around the Wolsung nuclear power plant (NPP) site during the period 2004-2008. The tritium concentrations in atmospheric water vapour and precipitation had a temporal variation with relatively high values in the early summer. Spatial distribution of tritium concentrations was affected by various factors such as distance from the NPP site, wind direction, tritium discharge into the atmosphere and atmospheric dispersion factor. The annual mean concentrations of atmospheric HTO and precipitation were correlated with the amount of gaseous tritium released from the Wolsung NPP. The tritium concentrations in precipitation decrease exponentially with an increase of the distance from the Wolsung NPP site.

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.

Hypertension (High Blood Pressure)

Science.gov (United States)

... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Teens / Hypertension (High Blood Pressure) What's ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

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.

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

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.

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

Spatial Heterodyne Observations of Water (SHOW) vapour in the upper troposphere and lower stratosphere from a high altitude aircraft: Modelling and sensitivity analysis

Science.gov (United States)

Langille, J. A.; Letros, D.; Zawada, D.; Bourassa, A.; Degenstein, D.; Solheim, B.

2018-04-01

A spatial heterodyne spectrometer (SHS) has been developed to measure the vertical distribution of water vapour in the upper troposphere and the lower stratosphere with a high vertical resolution (∼500 m). The Spatial Heterodyne Observations of Water (SHOW) instrument combines an imaging system with a monolithic field-widened SHS to observe limb scattered sunlight in a vibrational band of water (1363 nm-1366 nm). The instrument has been optimized for observations from NASA's ER-2 aircraft as a proof-of-concept for a future low earth orbit satellite deployment. A robust model has been developed to simulate SHOW ER-2 limb measurements and retrievals. This paper presents the simulation of the SHOW ER-2 limb measurements along a hypothetical flight track and examines the sensitivity of the measurement and retrieval approach. Water vapour fields from an Environment and Climate Change Canada forecast model are used to represent realistic spatial variability along the flight path. High spectral resolution limb scattered radiances are simulated using the SASKTRAN radiative transfer model. It is shown that the SHOW instrument onboard the ER-2 is capable of resolving the water vapour variability in the UTLS from approximately 12 km - 18 km with ±1 ppm accuracy. Vertical resolutions between 500 m and 1 km are feasible. The along track sampling capability of the instrument is also discussed.

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.

Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

CERN Document Server

Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

2002-01-01

The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

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.

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 ...

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.

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.

High-pressure apparatus

NARCIS (Netherlands)

Schepdael, van L.J.M.; Bartels, P.V.; Berg, van den R.W.

1999-01-01

The invention relates to a high-pressure device (1) having a cylindrical high-pressure vessel (3) and prestressing means in order to exert an axial pressure on the vessel. The vessel (3) can have been formed from a number of layers of composite material, such as glass, carbon or aramide fibers which

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.)

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.

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

Specific features of an interaction between laser radiation and matter at high pressures of an ambient medium

Energy Technology Data Exchange (ETDEWEB)

Rykalin, N N; Uglov, A A; Nizametdinov, M M [AN SSSR, Moscow. Inst. Metallurgii

1975-08-01

Study of the development of a plasma cloud in the vicinity of the target in nitrogen has been performed. The mechanism of discharge propagation is discussed. Variations of physical characteristics of targets exposed to radiation are considered. Experimental data concerning interaction of a neodymium laser radiation with materials (metals, dielectrics) under high pressure are given. It is demonstrated that the environmental pressure increase over the range 30-100 atm with the flux density 10/sup 6/-10/sup 7/ w/cm/sup 2/ results in a nearly complete screening of the target by the plasma cloud. The primary mechanism of zone formation of the laser radiation absorption in a cold gas under high pressures near the target is thermal emission (when the evaporation is insignificant) and the breakdown in the vapours of the evaporated substance. The major mechanism of sustaining the plasma cloud at flux densities of 1-10 Mw/cm/sup 2/ is slow burning. It is noted that the periodic variation of brightness of plasma after the radiation effect on dielectrics has terminated can be associated with the energy production in a chemical reaction, the development of which is determined by the time of reaching the temperature that depends on the particle size. The target characteristics in the interaction zone are considered, which depend on the radiation flux density and the gas pressure in the chamber.

Pressure pressure-balanced pH sensing system for high temperature and high pressure water

International Nuclear Information System (INIS)

Tachibana, Koji

1995-01-01

As for the pH measurement system for high temperature, high pressure water, there have been the circumstances that first the reference electrodes for monitoring corrosion potential were developed, and subsequently, it was developed for the purpose of maintaining the soundness of metallic materials in high temperature, high pressure water in nuclear power generation. In the process of developing the reference electrodes for high temperature water, it was clarified that the occurrence of stress corrosion cracking in BWRs is closely related to the corrosion potential determined by dissolved oxygen concentration. As the types of pH electrodes, there are metal-hydrogen electrodes, glass electrodes, ZrO 2 diaphragm electrodes and TiO 2 semiconductor electrodes. The principle of pH measurement using ZrO 2 diaphragms is explained. The pH measuring system is composed of YSZ element, pressure-balanced type external reference electrode, pressure balancer and compressed air vessel. The stability and pH response of YSZ elements are reported. (K.I.)

Economical surface treatment of die casting dies to prevent soldering in high pressure casting

International Nuclear Information System (INIS)

Fraser, D.T.; Jahedi, M.Z.

2001-01-01

This paper describes the use of a gas oxidation treatment of H13 tool steel to develop a compact iron oxide layer at the surface of core pins to prevent soldering in high pressure die casting. The performance of oxide layers in the protection of die steel against soldering during high pressure die casting was tested in a specially designed die using removable core pins and Al-11 Si-3 Cu casting alloy. The gas oxidation treatment can be applied at low temperatures and to large areas of the die surface. In addition this process is very cost effective compared to other coating processes such as physical vapour deposition (PVD), or thermo-reactive diffusion (TRD) coatings. This work demonstrated that surface treatment producing pure magnetite (Fe 3 O 4 ) layers are more protective than oxide layers containing a combination of Fe 3 O 4 (magnetite) and Fe 3 O 3 (haematite). The magnetite layer acts as a barrier between the die steel/casting alloy interface and prevents the formation of inter-metallic phases. Optical microscopy and scanning electron microscope were used to determine the thickness of the oxide layer, while X-ray diffraction was performed to determine the oxide phase structure

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

OpenAIRE

Putzhammer, Raphaela; Doppler, Christian; Jakschitz, Thomas; Heinz, Katharina; F?rste, 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 endothe...

PFS/Mars Express first results: water vapour and carbon monoxide global distribution

Science.gov (United States)

Ignatiev, N. I.; Titov, D. V.; Formisano, V.; Moroz, V. I.; Lellouch, E.; Encrenaz, Th.; Fouchet, T.; Grassi, D.; Giuranna, M.; Atreya, S.; Pfs Team

Planetary Fourier Spectrometer onboard Mars Express, with its wide spectral range (1.2--45 um) and high spectral resolution (1.4 cm-1), makes it possible to study in a self-consistent manner the Martian atmosphere by means of simultaneous analysis of spectral features in several spectral regions. As concerned small species, we observe 30--50, 6.3, 2.56, 1.87 and 1.38 μ m H2O bands, and 4.7 and 2.35 μ m CO bands. The most favourable, with respect to the instrument performance, 2.56 μ m H2O and 4.7 μ m CO bands, are used to study the variations of column abundance of water vapour and carbon monoxide on a global scale from pole to pole. All necessary atmospheric parameters, namely temperature profiles, surface pressure, and dust density are obtained from the same spectra, whenever possible.

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.

High Blood Pressure Facts

Science.gov (United States)

... Stroke Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir On ... Top of Page CDC Fact Sheets Related to High Blood Pressure High Blood Pressure Pulmonary Hypertension Heart Disease Signs ...

High Blood Pressure (Hypertension)

Science.gov (United States)

... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

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.

Carbon coated Fe, Co and Ni Nanoparticles produced by high pressure CVD and their potential for medical applications

Energy Technology Data Exchange (ETDEWEB)

El-Gendy, A.A.; Ibrahim, E.M.M.; Khavrus, V.; Krupskaya, Y.; Leonhardt, A.; Klingeler, R.; Buechner, B. [Leibniz Institute for Solid State and Materials Research (IFW), Dresden (Germany)

2009-07-01

Fe rate at C, Co rate at C and Ni rate at C nanocapsules have been produced by high pressure chemical vapour deposition (HPCVD). Scanning electron microscopy images prove that most of the particles are coated with carbon. High resolution transmission electron microscopy imaging confirms that these particles have a broad size distribution and a core/shell structure. In addition, individual nanoparticles are found inside a carbon capsule as well as several particles together in one shell. X-ray diffraction confirms the phases and allows calculating the average particle size from the width of the peaks. Our magnetisation studies confirm that the coated particles are ferromagnetic up to 400 K. AC magnetic heating studies have been performed which imply the potential of carbon coated nanomagnets for applications in hyperthermia therapies.

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.

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

High pressure effect for high-Tc superconductors

International Nuclear Information System (INIS)

Takahashi, Hiroki; Tomita, Takahiro

2011-01-01

A number of experimental and theoretical studies have been performed to understand the mechanism of high-T c superconductivity and to enhance T c . High-pressure techniques have played a very important role for these studies. In this paper, the high-pressure techniques and physical properties of high-T c superconductor under high pressure are presented. (author)

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.

3D imaging of vapour and liquid inclusions from the Mole Granite, Australia, using helical fluorescence tomography

Energy Technology Data Exchange (ETDEWEB)

Cauzid, J. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble Cedex (France)], E-mail: jean.cauzid@esrf.fr; Philippot, P. [Geobiosphere Actuelle et Primitive, Institut de Physique du Globe de Paris, CNRS and Universite Denis Diderot, Case 89, 4 place Jussieu, 75252 Paris Cedex 05 (France); Bleuet, P. [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble Cedex (France); Simionovici, A. [Laboratoire de Geophysique Interne et Tectonophysique, BP 53, 38041 Grenoble Cedex 9 (France); Somogyi, A. [Synchrotron Soleil, DiffAbs beamline, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette Cedex (France); Golosio, B. [Instituto di Matematica e Fisica, Universita di Sassari, 2 via Vienna, 07100 Sassari (Italy)

2007-08-15

World class Cu resources are concentrated in porphyry and epithermal ore deposits. Their formation remains partially understood, however, due to a lack of constraints on the partitioning properties of trace elements in general, and Cu in particular, between vapour and liquid phases evolved from boiling fluids at depth in the Earth's crust. Immiscible liquid and vapour fluid inclusions coexisting in a single quartz grain have been imaged in three dimensions by X-ray Fluorescence Computed Tomography (XFCT). Elemental spatial distributions confirm that Cu, and to a lesser extent As, partition into the vapour phase, whereas Mn, Fe, Zn, Br, Rb, Sr and Pb concentrate in the liquid inclusion. High resolution mapping of the vapour inclusions revealed that Cu is heterogeneously distributed at the scale of a single inclusion and is mostly concentrated as tiny daughter crystals.

3D imaging of vapour and liquid inclusions from the Mole Granite, Australia, using helical fluorescence tomography

Science.gov (United States)

Cauzid, J.; Philippot, P.; Bleuet, P.; Simionovici, A.; Somogyi, A.; Golosio, B.

2007-08-01

World class Cu resources are concentrated in porphyry and epithermal ore deposits. Their formation remains partially understood, however, due to a lack of constraints on the partitioning properties of trace elements in general, and Cu in particular, between vapour and liquid phases evolved from boiling fluids at depth in the Earth's crust. Immiscible liquid and vapour fluid inclusions coexisting in a single quartz grain have been imaged in three dimensions by X-ray Fluorescence Computed Tomography (XFCT). Elemental spatial distributions confirm that Cu, and to a lesser extent As, partition into the vapour phase, whereas Mn, Fe, Zn, Br, Rb, Sr and Pb concentrate in the liquid inclusion. High resolution mapping of the vapour inclusions revealed that Cu is heterogeneously distributed at the scale of a single inclusion and is mostly concentrated as tiny daughter crystals.

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.

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.

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

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.

Reduced Pressure-Chemical Vapour Deposition of Si/SiGe heterostructures for nanoelectronics

International Nuclear Information System (INIS)

Hartmann, J.M.; Andrieu, F.; Lafond, D.; Ernst, T.; Bogumilowicz, Y.; Delaye, V.; Weber, O.; Rouchon, D.; Papon, A.M.; Cherkashin, N.

2008-01-01

We have first of all quantified the impact of pressure on Si and SiGe growth kinetics. Definite growth rate and Ge concentration increases with the pressure have been evidenced at low temperatures (650-750 deg. C). By contrast, the high temperature (950-1050 deg. C) Si growth rate either increases or decreases with pressure (gaseous precursor depending). We have then described the selective epitaxial growth process we use to form Si or Si 0.7 Ge 0.3 :B raised sources and drains on ultra-thin patterned Silicon-On-Insulator (SOI) substrates. We have afterwards presented the specifics of SiGe virtual substrates and of the tensile-strained Si layers grown on top (used as templates for the elaboration of tensily strained-SOI wafers). The tensile strain, which can be tailored from 1.3 up to 3 GPa, leads to an electron mobility gain by a factor of 2 in n-Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) built on top. High Ge content SiGe virtual substrates can also be used for the elaboration of compressively strained Ge channels, with impressive hole mobility gains (x9) compared to bulk Si. After that, we have described the main structural features of thick Ge layers grown directly on Si (that can be used as donor wafers for the elaboration of GeOI wafers or as the active medium of near infrared photo-detectors). Finally, we have shown how Si/SiGe multilayers can be used for the formation of high performance 3D devices such as multi-bridge channel or nano-beam gate-all-around FETs, the SiGe sacrificial layers being removed thanks to plasma dry etching, wet etching or in situ gaseous HCl etching

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.

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

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.

High pressure solubility data of carbon dioxide in (tri-iso-butyl(methyl)phosphonium tosylate + water) systems

Energy Technology Data Exchange (ETDEWEB)

Ventura, Sonia P.M. [CICECO, Departamento de Quimica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Pauly, Jerome; Daridon, Jean L. [Laboratoire Haute Pression Centre Universitaire de Recherche Scientifique, Universite de Pau, Avenue de l' Universite, 64000 Pau (France); Lopes da Silva, J.A.; Marrucho, Isabel M. [CICECO, Departamento de Quimica, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Dias, Ana. M.A. [IBB-Instituto de Biotecnologia e Bioengenharia, Centro de Engenharia Biologica, Universidade do Minho, Campus de Gualtar, 4710-553 Braga (Portugal); Coutinho, Joao A.P. [CICECO, Departamento de Quimica, Universidade de Aveiro, 3810-193 Aveiro (Portugal)], E-mail: jcoutinho@ua.pt

2008-08-15

Ionic liquids are attracting great attention nowadays due to their interesting properties which make them useful in a broad range of applications including reaction media or separation/capture of environmentally hazardous gases such as carbon dioxide. In many cases, for practical and/or economical reasons, the use of aqueous solutions of ILs would be preferable to their use as pure compounds. In this work, high pressure equilibrium data for the {l_brace}carbon dioxide (CO{sub 2}) + tri-iso-butyl(methyl)phosphonium tosylate [iBu{sub 3}MeP][TOS] + water system were measured at temperatures ranging from (276 to 370) K and pressures up to 100 MPa. Measurements were performed using a high-pressure cell with a sapphire window that allows direct observation of the liquid-vapour transition. Mixtures with different IL concentrations were studied in order to check the influence of the amount of IL on the solubility of CO{sub 2} in the aqueous mixture. The results show that the presence of IL enhances the solubility of CO{sub 2} in the (IL + water) system revealing a salting-in effect of the IL on the solubility of CO{sub 2}. The appearance of a three phase region was observed for IL concentrations higher than 4 mol% of IL in water when working at pressures between 4 and 8 MPa and temperatures between (280 and 305) K. In this range, the upper limit of the VLE region observed is shown to increase with the temperature being almost independent of the IL initial concentration in the mixture.

High pressure X-ray studies

International Nuclear Information System (INIS)

Sikka, S.K.

1981-01-01

High pressure research has already led to new insights in the physical properties of materials and at times to the synthesis of new ones. In all this, X-ray diffraction has been a valuable diagnostic experimental tool. In particular, X-rays in high pressure field have been used (a) for crystallographic identification of high pressure polymorphs and (b) for study of the effect of pressure on lattice parameters and volume under isothermal conditions. The results in the area (a) are reviewed. The techniques of applying high pressures are described. These include both static and dynamic shockwave X-ray apparatus. To illustrate the effect of pressure, some of the pressure induced phase transitions in pure metals are described. It has been found that there is a clear trend for elements in any group of the periodic table to adopt similar structures at high pressures. These studies have enabled to construct generalized phase diagrams for many groups. In the case of alloys, the high pressure work done on Ti-V alloys is presented. (author)

High Blood Pressure (Hypertension) (For Parents)

Science.gov (United States)

... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Parents / Hypertension (High Blood Pressure) What's ... High Blood Pressure) Treated? Print What Is Hypertension (High Blood Pressure)? Blood pressure is the pressure of blood against ...

High-pressure crystallography

Science.gov (United States)

Katrusiak, A.

2008-01-01

The history and development of high-pressure crystallography are briefly described and examples of structural transformations in compressed compounds are given. The review is focused on the diamond-anvil cell, celebrating its 50th anniversary this year, the principles of its operation and the impact it has had on high-pressure X-ray diffraction.

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.

Cryogenic, Absolute, High Pressure Sensor

Science.gov (United States)

Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

2001-01-01

A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

Cryogenic High Pressure Sensor Module

Science.gov (United States)

Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

1999-01-01

A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

High-Tc superconductors under very high pressure

International Nuclear Information System (INIS)

Wijngaarden, R.J.; Scholtz, J.J.; Eenige, E.N. van; Griessen, R.

1991-01-01

High pressure has played a crucial role in the short history of high T c superconductors. Soon after the discovery of superconductivity by Bednorz and Muller in La-Ba-Cu-O, Chu et al. showed that the critical temperature T c could be significantly increased by pressure. This observation led to the discovery of YBa 2 Cu 3 O 7 by Wu et al. with a T c above 90 K. Incidentally, this high T c is probably also due to the fact that YBa 2 Cu 3 O 7 has two CuO 2 layers per unit cell instead of a single one in La-Ba-Cu-O. The authors discuss the high pressure dependence of the oxide superconductors, particularly at pressures above 10 GPa, and the nonmonotonic dependence of transition temperature on pressure

Experimental study to distinguish the effects of methanol slip and water vapour on a high temperature PEM fuel cell at different operating conditions

DEFF Research Database (Denmark)

Thomas, Sobi; Vang, Jakob Rabjerg; Araya, Samuel Simon

2017-01-01

The objective of this paper is to separate out the effects of methanol and water vapour on a high temperature polymer electrolyte membrane fuel cell under different temperatures (160°C and 180°C) and current densities (0.2Acm-2, 0.4Acm-2 and 0.6Acm-2). The degradation rates at the different curre...

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.

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.

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.

Thermalisation of high energy electrons and positrons in water vapour

Science.gov (United States)

Munoz, A.; Blanco, F.; Limao-Vieira, P.; Thorn, P. A.; Brunger, M. J.; Buckman, S. J.; Garcia, G.

2008-07-01

In this study we describe a method to simulate single electron tracks of electrons in molecular gases, particularly in water vapour, from relatively high energies, where Born (Inokuti 1971) approximation is supposed to be valid, down to thermal energies paying special attention to the low energy secondary electrons which are abundantly generated along the energy degradation procedure. Experimental electron scattering cross sections (Munoz et al. 2007) and energy loss spectra (Thorn et al. 2007) have been determined, where possible, to be used as input parameters of the simulating program. These experimental data have been complemented with optical potential calculation (Blanco and Garcia 2003) providing a complete set of interaction probability functions for each type of collision which could take place in the considered energy range: elastic, ionization, electronic excitation, vibrational and rotational excitation. From the simulated track structure (Munoz et al. 2005) information about energy deposition and radiation damage at the molecular level can be derived. A similar procedure is proposed to the study of single positron tracks in gases. Due to the lack of experimental data for positron interaction with molecules, especially for those related to energy loss and excitation cross sections, some distribution probability data have been derived from those of electron scattering by introducing positron characteristics as positroniun formation. Preliminary results for argon are presented discussing also the utility of the model to biomedical applications based on positron emitters.

Controlling your high blood pressure

Science.gov (United States)

... medlineplus.gov/ency/patientinstructions/000101.htm Controlling your high blood pressure To use the sharing features on this page, ... JavaScript. Hypertension is another term used to describe high blood pressure. High blood pressure can lead to: Stroke Heart ...

Phase behaviour of pseudo-binary systems of pressurized ((propane + L,L-lactide)) at different ethanol to L,L-lactide mole ratios

International Nuclear Information System (INIS)

Bender, João P.; Tres, Marcus V.; Corazza, Marcos L.; Ferreira, Sandra R.S.; Oliveira, J. Vladimir

2014-01-01

Highlights: • Phase equilibrium data of (propane + L,L-lactide) system at different ethanol to monomer mole ratios. • Static synthetic method from (323 to 353) K and pressures up to 3.3 MPa. • (Vapour + liquid) (VLE) was observed with bubble point (BP) type transitions. • Experimental modelled using the Peng–Robinson (PR) equation with the Wong–Sandler (PR–WS) rule. - Abstract: This work reports phase equilibrium data of pressurized (propane + L,L-lactide) system at different ethanol to monomer mole ratios (9:1; 7:1; 5:1). Phase equilibrium experiments were accomplished in a high-pressure variable-volume view cell employing the static synthetic method. (Vapour + liquid) equilibrium data for the pseudo-binary systems were determined within the temperature range from (323 to 353) K and pressures up to 3.3 MPa. For the systems investigated, (vapour + liquid) equilibrium (VLE) was visually recorded. It was observed that an increase in temperature or in propane concentration led to a pronounced rise in pressure transition values. On the other hand, an increase in the ethanol to L,L-lactide mole ratio led to a reduction in pressure transitions, whereas a reduction in ethanol concentration complicates the achievement of one-phase homogeneous system. Thus, rapid complete miscibility of the system can be controlled by the amount of ethanol added as a co-solvent. The experimental results were modelled using the Peng–Robinson (PR) equation of state with the Wong–Sandler (PR–WS) mixing rule, providing a good representation of the experimental phase transition points

High pressure study of high-temperature superconductors

Energy Technology Data Exchange (ETDEWEB)

Souliou, Sofia-Michaela

2014-09-29

The current thesis studies experimentally the effect of high external pressure on high-T{sub c} superconductors. The structure and lattice dynamics of several members of the high-T{sub c} cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa{sub 2}Cu{sub 3}O{sub 6.55} samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa{sub 2}Cu{sub 4}O{sub 8}. A clear renormalization of some of the Raman phonons is seen below T{sub c} as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B{sub 1g}-like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa{sub 2}Cu{sub 3}O{sub 6+x}. At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group

High pressure study of high-temperature superconductors

International Nuclear Information System (INIS)

Souliou, Sofia-Michaela

2014-01-01

The current thesis studies experimentally the effect of high external pressure on high-T c superconductors. The structure and lattice dynamics of several members of the high-T c cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T c superconductor YBa 2 Cu 3 O 6+x have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa 2 Cu 3 O 6.55 samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa 2 Cu 4 O 8 . A clear renormalization of some of the Raman phonons is seen below T c as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B 1g -like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa 2 Cu 3 O 6+x . At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group Imm2). The structural transition is clearly reflected in the high pressure

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}.

High blood pressure - children

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... this page: //medlineplus.gov/ency/article/007696.htm High blood pressure - children To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

High blood pressure - infants

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/007329.htm High blood pressure - infants To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

High blood pressure medications

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

WATER VAPOUR PERMEABILITY PROPERTIES OF CELLULAR WOOD MATERIAL AND CONDENSATION RISK OF COMPOSITE PANEL WALLS

Directory of Open Access Journals (Sweden)

Janis IEJAVS

2016-09-01

Full Text Available Invention of light weight cellular wood material (CWM with a trade mark of Dendrolight is one of innovations in wood industry of the last decade. The aim of the research was to define the water vapour permeability properties of CWM and to analyse the condensation risk of various wall envelopes where solid wood cellular material is used. To determine the water vapour permeability of CWM, test samples were produced in the factory using routine production technology and tested according to the standard EN 12086:2014. Water vapour permeability factor (μ and other properties of six different configurations of CWM samples were determined. Using the experimental data the indicative influence of geometrical parameters such as lamella thickness, number of lamellas and material direction were investigated and evaluated. To study the condensation risk within the wall envelope containing CWM calculation method given in LVS EN ISO 13788:2012 was used. To ease the calculation process previously developed JavaScript calculation software that had only capability to calculate thermal transmittance was extended so that condensation risk in multi-layer composite walls can be analysed. Water vapour permeability factor in CWM is highly direction dependant. If parallel and perpendicular direction of CWM is compared the value of water vapour permeability factor can differentiate more than two times. Another significant factor for condensation risk analysis is overall thickness of CWM since it directly influences the equivalent air layer thickness. The influence of other factors such as lamella thickness, or groove depth is minor when water vapour permeability properties are compared. From the analysis of CWM performance in building envelope it can be concluded that uninsulated CWM panels used during winter months will pose the risk of condensation damage to structure, but the risk can be reduced or prevented if insulation layer is applied to the CWM panel wall

"Secrets" of High Pressure Phase Equilibrium Experiment.

Czech Academy of Sciences Publication Activity Database

Wichterle, Ivan

2005-01-01

Roč. 54, č. 11 (2005), s. 477-479 ISSN 0022-9830 Institutional research plan: CEZ:AV0Z40720504 Keywords : vapour-liquid equilibrium * experimental work Subject RIV: CF - Physical ; Theoretical Chemistry

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...

High-pressure tritium

International Nuclear Information System (INIS)

Coffin, D.O.

1976-01-01

Some solutions to problems of compressing and containing tritium gas to 200 MPa at 700 0 K are discussed. The principal emphasis is on commercial compressors and high-pressure equipment that can be easily modified by the researcher for safe use with tritium. Experience with metal bellows and diaphragm compressors has been favorable. Selection of materials, fittings, and gauges for high-pressure tritium work is also reviewed briefly

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

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.

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

High-pressure boron hydride phases

International Nuclear Information System (INIS)

Barbee, T.W. III; McMahan, A.K.; Klepeis, J.E.; van Schilfgaarde, M.

1997-01-01

The stability of boron-hydrogen compounds (boranes) under pressure is studied from a theoretical point of view using total-energy methods. We find that the molecular forms of boranes known to be stable at ambient pressure become unstable at high pressure, while structures with extended networks of bonds or metallic bonding are energetically favored at high pressures. If such structures are metastable on return to ambient pressure, they would be energetic as well as dense hydrogen storage media. An AlH 3 -like structure of BH 3 is particularly interesting in that it may be accessible by high-pressure diamond anvil experiments, and should exhibit both second-order structural and metal-insulator transitions at lower pressures. copyright 1997 The American Physical Society

Preparation and mass spectrometrical high temperature investigations on compounds of the quasi-ternary system Cs2O-Al2O3-SiO2

International Nuclear Information System (INIS)

Odoj, R.; Hilpert, K.; Nuernberg, H.W.

1977-09-01

Additions of aluminium oxide and silicen oxide to ceramic fuel for pyrocarbon-coated nuclear fuel paticles counteract a release of fission-cesium by compound formation. The vapourization tests carried out here using samples from the quasi-ternary system cesium-oxide-aluminium-oxide-silicon-oxide by means of high-temperature mass spectroscopy using a Knudsen cell served the optimization of this retention effect. The aim of the apparative changes on the knudsen cell were to shield heat radiation on the temperature measuring borehole through the tungsten wire cathode in order to be able to perform exact temperature measurements even below 1,000 0 C. A new method of preparation was developed to obtain defined cesium aluminium silicates whose composition was determined by Guinier and goniometer pictures as well as by microscopic investigations. According to the latter, 3 ternary compounds are present in the system investigated: CsAlSiO 4 , CsAlSi 2 O 6 and CsAlSi 5 O 12 . Their lattice constants were determined from goniometric measurements; the vapour pressure equection were set up from the measured cesium vapour pressure values over each sample and the enthalpies of the vapourization reactions were found to be 84 kcal for CsAlSiO 4 at 1,400 0 K, 100 kcal for CsAlSi 2 O 6 at 1,550 0 K and 122 kcal for CsAlSi 5 O 12 at 1,650 0 K. The cesium vapour pressures of the glas phases investigated of the system are above the Cs partial pressures of the solid crystalline phases of the same composition. The results of the work explain the causes of the reduction of the Cs release and show that the vapour pressure can be lowered by more than 10 orders of magnitude at reactor relevant temperatures by compound formation. (RB) [de

Psoriasis and high blood pressure.

Science.gov (United States)

Salihbegovic, Eldina Malkic; Hadzigrahic, Nermina; Suljagic, Edin; Kurtalic, Nermina; Sadic, Sena; Zejcirovic, Alema; Mujacic, Almina

2015-02-01

Psoriasis is a chronic skin ailment which can be connected with an increased occurrence of other illnesses, including high blood pressure. A prospective study has been conducted which included 70 patients affected by psoriasis, both genders, older than 18 years. Average age being 47,14 (SD= ±15,41) years, from that there were 36 men or 51,43 and 34 women or 48,57%. Average duration of psoriasis was 15,52 (SD=±12,54) years. Frequency of high blood pressure in those affected by psoriasis was 54,28%. Average age of the patients with psoriasis and high blood pressure was 53,79 year (SD=±14,15) and average duration of psoriasis was 17,19 years (SD=±13,51). Average values of PASI score were 16,65. Increase in values of PASI score and high blood pressure were statistically highly related (r=0,36, p=0,0001). Psoriasis was related to high blood pressure and there was a correlation between the severity of psoriasis and high blood pressure.

High-pressure torsion of hafnium

International Nuclear Information System (INIS)

Edalati, Kaveh; Horita, Zenji; Mine, Yoji

2010-01-01

Pure Hf (99.99%) is processed by high-pressure torsion (HPT) under pressures of 4 and 30 GPa to form an ultrafine-grained structure with a gain size of ∼180 nm. X-ray diffraction analysis shows that, unlike Ti and Zr, no ω phase formation is detected after HPT processing even under a pressure of 30 GPa. A hydride formation is detected after straining at the pressure of 4 GPa. The hydride phase decomposes either by application of a higher pressure as 30 GPa or by unloading for prolong time after HPT processing. Microhardness, tensile and bending tests show that a high hardness (360 Hv) and an appreciable ductility (8%) as well as high tensile and bending strength (1.15 and 2.75 GPa, respectively) are achieved following the high-pressure torsion.

Preventing High Blood Pressure

Science.gov (United States)

... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

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.)

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.

Can painted glass felt or glass fibre cloth be used as vapour barrier?

DEFF Research Database (Denmark)

El-Khattam, Amira; Andersen, Mie Them; Hansen, Kurt Kielsgaard

2014-01-01

In most Nordic homes the interior surfaces of walls and ceilings have some kind of surface treatment for aesthetical reasons. The treatments can for example be glass felt or glass fibre cloth which are painted afterwards. To evaluate the hygrothermal performance of walls and ceilings...... treatments. The surface treatments were glass felt or glass fibre cloth with different types of paints or just paint. The paint types were acrylic paint and silicate paint. The results show that the paint type has high influence on the water vapour resistance while the underlay i.e. glass felt or glass fibre...... acrylic paint on glass felt or glass fibre cloth cannot be used instead of a vapour barrier....

High sensitivity of a carbon nanowall-based sensor for detection of organic vapours

Czech Academy of Sciences Publication Activity Database

Slobodian, P.; Cvelbar, U.; Říha, Pavel; Olejník, R.; Matyáš, J.; Filipič, G.; Watanabe, H.; Tajima, S.; Kondo, H.; Sekine, M.; Hori, M.

2015-01-01

Roč. 110, č. 5 (2015), s. 90515-90520 ISSN 2046-2069 Grant - others:Ministerstvo školství, mládeže a tělovýchovy (MŠMT)(CZ) LO1504; Slovenian Research Agency(SI) L2-6769; Slovenian Research Agency(SI) Bi-JAP-2015-2017-3; JSPS Grant-in-Aid for Exploratory Research(JP) 25600123 Institutional research plan: CEZ:AV0Z20600510 Institutional support: RVO:67985874 Keywords : carbon nanowalls * sensing properties * volatile organic vapours Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 3.289, year: 2015

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

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.

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.

Phase transitions in solids under high pressure

CERN Document Server

Blank, Vladimir Davydovich

2013-01-01

Phase equilibria and kinetics of phase transformations under high pressureEquipment and methods for the study of phase transformations in solids at high pressuresPhase transformations of carbon and boron nitride at high pressure and deformation under pressurePhase transitions in Si and Ge at high pressure and deformation under pressurePolymorphic α-ω transformation in titanium, zirconium and zirconium-titanium alloys Phase transformations in iron and its alloys at high pressure Phase transformations in gallium and ceriumOn the possible polymorphic transformations in transition metals under pressurePressure-induced polymorphic transformations in АIBVII compoundsPhase transformations in AIIBVI and AIIIBV semiconductor compoundsEffect of pressure on the kinetics of phase transformations in iron alloysTransformations during deformation at high pressure Effects due to phase transformations at high pressureKinetics and hysteresis in high-temperature polymorphic transformations under pressureHysteresis and kineti...

High Blood Pressure (Hypertension)

Science.gov (United States)

... other risk factors, like diabetes, you may need treatment. How does high blood pressure affect pregnant women? A few women will get ... HIV, Birth Control Heart Health for Women Pregnancy Menopause More Women's Health ... High Blood Pressure--Medicines to Help You Women and Diabetes Heart ...

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.

Pressure-Drop Considerations in the Characterization of Dew-Point Transfer Standards at High Temperatures

Science.gov (United States)

Mitter, H.; Böse, N.; Benyon, R.; Vicente, T.

2012-09-01

During calibration of precision optical dew-point hygrometers (DPHs), it is usually necessary to take into account the pressure drop induced by the gas flow between the "point of reference" and the "point of use" (mirror or measuring head of the DPH) either as a correction of the reference dew-point temperature or as part of the uncertainty estimation. At dew-point temperatures in the range of ambient temperature and below, it is sufficient to determine the pressure drop for the required gas flow, and to keep the volumetric flow constant during the measurements. In this case, it is feasible to keep the dry-gas flow into the dew-point generator constant or to measure the flow downstream the DPH at ambient temperature. In normal operation, at least one DPH in addition to the monitoring DPH are used, and this operation has to be applied to each instrument. The situation is different at high dew-point temperatures up to 95 °C, the currently achievable upper limit reported in this paper. With increasing dew-point temperatures, the reference gas contains increasing amounts of water vapour and a constant dry-gas flow will lead to a significant enhanced volume flow at the conditions at the point of use, and therefore, to a significantly varying pressure drop depending on the applied dew-point temperature. At dew-point temperatures above ambient temperature, it is also necessary to heat the reference gas and the mirror head of the DPH sufficiently to avoid condensation which will additionally increase the volume flow and the pressure drop. In this paper, a method is provided to calculate the dry-gas flow rate needed to maintain a known wet-gas flow rate through a chilled mirror for a range of temperature and pressures.

Fundamentals of high pressure adsorption

Energy Technology Data Exchange (ETDEWEB)

Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

2009-12-15

High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

Impact of major volcanic eruptions on stratospheric water vapour

Directory of Open Access Journals (Sweden)

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

Directory of Open Access Journals (Sweden)

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.

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

Heat and water mass transfer in unsaturated swelling clay based buffer: discussion on the effect of the thermal gradient and on the diffusion of water vapour

Energy Technology Data Exchange (ETDEWEB)

Robinet, J.O. [Euro-Geomat-Consulting (France)]|[Institut National des Sciences Appliquees (INSA), 35 - Rennes (France); Plas, F. [Agence Nationale pour la Gestion des Dechets Radioactifs (ANDRA), 92 - Chatenay Malabry (France)

2005-07-01

The modelling of heat, mass transfer and the behaviour coupled thermo-hydro-mechanical in swelling clay require the development of appropriate constitutive laws as well as experimental data. This former approach, allows the quantitative validation of the theoretical models. In general modelling approaches consider dominant mechanisms, (i) Fourier law for diffusion of heat, (ii) generalized Darcy law for convection of liquid water, (iii) Flick law for diffusion of water vapour, and elastic-plastic models wit h hydric hardening and thermal damage/expansion for strain-stress behaviour. Transfer of dry air and water under thermal gradient and capillary (e.g. suction) gradient in unsaturated compacted swelling clays consider evaporation, migration and condensation. These transfers take into account the capillary effect. This effect is an evaporation of liquid water in the hot part for temperature higher than 100 C associated with a, diffusion of water vapor towards cold part then condensation, and convection of liquid water with gradient of suction in the opposite direction of the water vapour diffusion. High values of the diffusion coefficient of the vapour water are considered about 10{sup -7}m{sup 2}/s. Some thermal experiments related (i) low values of the water vapour diffusion coefficient in compacted swelling clays, 2004) and (ii) a significant drying associated with a water transfer even for temperature lower than 100 C. Other enhancement phenomena are used to explain these data and observations: the vaporization is a continuous process. At short term the mechanism of drying at short term is the thermal effect on the capillary pressure (e.g. surface tension depending of temperature); the thermal gradient is a driving force. When a temperature gradient is applied, diffusion occurs in order to reach equilibrium, e.g. to make the chemical potential (m) of each component uniform throughout. This mechanism is called thermal diffusion. This paper proposes a discussion

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

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.

Introducing zinc cations into zeolite Y via the reduction of HY with zinc metal vapour

Science.gov (United States)

Seidel, A.; Boddenberg, B.

1996-01-01

Zeolites HY and NaY which were contacted with zinc metal vapour at 420°C were investigated by carbon monoxide and xenon adsorption as well as 129Xe NMR spectroscopy. The reaction of zeolite HY results in the incorporation of Zn 2+ cations which are shown to populate the supercage positions S II and S III to an unusually high extent. The supercage zinc cation concentration strongly decreases when the material is saturated with water and subsequently dehydrated at 400°C. The zeolite NaY turns out to be inert towards the reaction with zinc metal vapour.

Evaluation of high temperature pressure sensors

International Nuclear Information System (INIS)

Choi, In-Mook; Woo, Sam-Yong; Kim, Yong-Kyu

2011-01-01

It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.

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.

Automated high pressure cell for pressure jump x-ray diffraction.

Science.gov (United States)

Brooks, Nicholas J; Gauthe, Beatrice L L E; Terrill, Nick J; Rogers, Sarah E; Templer, Richard H; Ces, Oscar; Seddon, John M

2010-06-01

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

Automated high pressure cell for pressure jump x-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M. [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Terrill, Nick J. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Rogers, Sarah E. [ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom)

2010-06-15

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

Automated high pressure cell for pressure jump x-ray diffraction

International Nuclear Information System (INIS)

Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M.; Terrill, Nick J.; Rogers, Sarah E.

2010-01-01

A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

African Americans and High Blood Pressure

Science.gov (United States)

ANSWERS by heart Lifestyle + Risk Reduction High Blood Pressure What About African Americans and High Blood Pressure? African Americans in the U.S. have a higher prevalence of high blood pressure (HBP) than ...

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

High pressure metrology for industrial applications

Science.gov (United States)

Sabuga, Wladimir; Rabault, Thierry; Wüthrich, Christian; Pražák, Dominik; Chytil, Miroslav; Brouwer, Ludwig; Ahmed, Ahmed D. S.

2017-12-01

To meet the needs of industries using high pressure technologies, in traceable, reliable and accurate pressure measurements, a joint research project of the five national metrology institutes and the university was carried out within the European Metrology Research Programme. In particular, finite element methods were established for stress-strain analysis of elastic and nonlinear elastic-plastic deformation, as well as of contact processes in pressure-measuring piston-cylinder assemblies, and high-pressure components at pressures above 1 GPa. New pressure measuring multipliers were developed and characterised, which allow realisation of the pressure scale up to 1.6 GPa. This characterisation is based on research including measurements of material elastic constants by the resonant ultrasound spectroscopy, hardness of materials of high pressure components, density and viscosity of pressure transmitting liquids at pressures up to 1.4 GPa and dimensional measurements on piston-cylinders. A 1.6 GPa pressure system was created for operation of the 1.6 GPa multipliers and calibration of high pressure transducers. A transfer standard for 1.5 GPa pressure range, based on pressure transducers, was built and tested. Herewith, the project developed the capability of measuring pressures up to 1.6 GPa, from which industrial users can calibrate their pressure measurement devices for accurate measurements up to 1.5 GPa.

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 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.

What Is High Blood Pressure?

Science.gov (United States)

... Disease Venous Thromboembolism Aortic Aneurysm More What is High Blood Pressure? Updated:Feb 27,2018 First, let’s define high ... resources . This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

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.

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

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.

Wavelength dependence four-wave mixing spectroscopy in a micrometric atomic vapour

International Nuclear Information System (INIS)

Yuan-Yuan, Li; Li, Li; Yan-Peng, Zhang; Si-Wen, Bi

2010-01-01

This paper presents a theoretical study of wavelength dependence four-wave-mixing (FWM) spectroscopy in a micrometric thin atomic vapour. It compares three cases termed as mismatched case I, matched case and mismatched case II for the probe wavelength less, equal and greater than the pump wavelength respectively. It finds that Dicke-narrowing can overcome width broadening induced by Doppler effects and polarisation interference of thermal atoms, and high resolution FWM spectra can be achieved both in matched and mismatched wavelength for many cases. It also finds that the magnitude of the FWM signal can be dramatically modified to be suppressed or to be enhanced in comparison with that of matched wavelength in mismatched case I or II. The width narrowing and the magnitude suppression or enhancement can be demonstrated by considering enhanced contribution of slow atoms induced by atom-wall collision and transient effect of atom-light interaction in a micrometric thin vapour. (general)

Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour.

Science.gov (United States)

Nagai, Masatsugu; Nakanishi, Kazuhiro; Takahashi, Hiraku; Kato, Hiromitsu; Makino, Toshiharu; Yamasaki, Satoshi; Matsumoto, Tsubasa; Inokuma, Takao; Tokuda, Norio

2018-04-27

Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

High Pressure Biomass Gasification

Energy Technology Data Exchange (ETDEWEB)

Agrawal, Pradeep K [Georgia Tech Research Corporation, Atlanta, GA (United States)

2016-07-29

According to the Billion Ton Report, the U.S. has a large supply of biomass available that can supplement fossil fuels for producing chemicals and transportation fuels. Agricultural waste, forest residue, and energy crops offer potential benefits: renewable feedstock, zero to low CO₂ emissions depending on the specific source, and domestic supply availability. Biomass can be converted into chemicals and fuels using one of several approaches: (i) biological platform converts corn into ethanol by using depolymerization of cellulose to form sugars followed by fermentation, (ii) low-temperature pyrolysis to obtain bio-oils which must be treated to reduce oxygen content via HDO hydrodeoxygenation), and (iii) high temperature pyrolysis to produce syngas (CO + H₂). This last approach consists of producing syngas using the thermal platform which can be used to produce a variety of chemicals and fuels. The goal of this project was to develop an improved understanding of the gasification of biomass at high pressure conditions and how various gasification parameters might affect the gasification behavior. Since most downstream applications of synags conversion (e.g., alcohol synthesis, Fischer-Tropsch synthesis etc) involve utilizing high pressure catalytic processes, there is an interest in carrying out the biomass gasification at high pressure which can potentially reduce the gasifier size and subsequent downstream cleaning processes. It is traditionally accepted that high pressure should increase the gasification rates (kinetic effect). There is also precedence from coal gasification literature from the 1970s that high pressure gasification would be a beneficial route to consider. Traditional approach of using thermogravimetric analyzer (TGA) or high-pressure themogravimetric analyzer (PTGA) worked well in understanding the gasification kinetics of coal gasification which was useful in designing high pressure coal gasification processes. However

High pressure phase transformations revisited

Science.gov (United States)

Levitas, Valery I.

2018-04-01

High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

High pressure phase transformations revisited.

Science.gov (United States)

Levitas, Valery I

2018-04-25

High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

High blood pressure - adults

Science.gov (United States)

... pressure is found. This is called essential hypertension. High blood pressure that is caused by another medical condition or medicine you are taking is called secondary hypertension. Secondary hypertension may be due to: Chronic ...

High blood pressure - medicine-related

Science.gov (United States)

Drug-induced hypertension is high blood pressure caused by using a chemical substance or medicine. ... of the arteries There are several types of high blood pressure : Essential hypertension has no cause that can be ...

Evaluation of electrical conductivity in high-pressure plasmas formed in xenon with sodium as additive

Energy Technology Data Exchange (ETDEWEB)

Novakovic, N V [Faculty of Philosophy, Nis (Yugoslavia); Stojilkovic, S M [Faculty of Electronics, Nis (Yugoslavia); Milic, B S [Dept. of Physics and Meteorology, Faculty of Natural and Mathematical Sciences, Belgrade (Yugoslavia)

1990-02-01

Results of a numerical evaluation of the electrical conductivity in high-pressure plasmas of intermediate degrees of ionization formed in xenon with, respectively, 1% and 10% of sodium are presented, for temperatures between 2000 K and 20 000 K, and for pressures ranging from the normal atmospheric value p{sub atm} = 0.1 MPa up to 2.5 MPa. The equilibrium plasma composition, necessary for the evaluations, was determined on the ground of the Saha equations combined with the charge conservation relation and the assumption that the pressure remained constant in the course of temperature variations. The ionization energy lowering, required in conjunction with the Saha equations, was obtained with the aid of a modified expression for the plasma Debye radius proposed previously. The electron elastic collisions with the charged particles were described by the Spitzer-Haerm (or, rather, Rutherford) formula, and those with the neutrals were taken into account by a polynomial formula interpolating some selected experimental results. The evaluated electrical conductivity is found to increase with the pressure at fixed temperature (except in the mixture with 10% of sodium, in which case an indistinct maximum at p = 10 p{sub atm} can be seen for 6000 K). This feature is opposite to what is found in pure xenon plasma and, except in the upper part of the temperature range analysed, agrees well with the behaviour of pure alkaline vapours. The numerical values obtained for the electrical conductivity are smaller than the figures resulting from the approximate formulae commonly used in numerical estimates of this transport coefficient in moderately non-ideal plasmas of intermediate degrees of ionization, much in accordance with the trends suggested by the experiment. (orig.).

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

High-pressure microbiology

National Research Council Canada - National Science Library

Michiels, Chris; Bartlett, Douglas Hoyt; Aertsen, Abram

2008-01-01

... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. High Hydrostatic Pressure Effects in the Biosphere: from Molecules to Microbiology * Filip Meersman and Karel Heremans . . . . . . . . . . . . 2. Effects...

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

High-purity aluminium creep under high hydrostatic pressure

International Nuclear Information System (INIS)

Zajtsev, V.I.; Lyafer, E.I.; Tokij, V.V.

1977-01-01

The effect of the hydrostatic pressure on the rate of steady-state creep of high-purity aluminium was investigated. It is shown that the hydrostatic pressure inhibits the creep. The activation volume of the creep is independent of the direction in the range of (4.7-6.2) kg/mm 2 and of the pressure in the range of (1-7.8000) atm. It is concluded that self-diffusion does not control the creep of high-purity aluminium at room temperature in the investigated stress and pressure range

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,.

High pressure experimental water loop

International Nuclear Information System (INIS)

Grenon, M.

1958-01-01

A high pressure experimental water loop has been made for studying the detection and evolution of cladding failure in a pressurized reactor. The loop has been designed for a maximum temperature of 360 deg. C, a maximum of 160 kg/cm 2 and flow rates up to 5 m 3 /h. The entire loop consists of several parts: a main circuit with a canned rotor circulation pump, steam pressurizer, heating tubes, two hydro-cyclones (one de-gasser and one decanter) and one tubular heat exchanger; a continuous purification loop, connected in parallel, comprising pressure reducing valves and resin pots which also allow studies of the stability of resins under pressure, temperature and radiation; following the gas separator is a gas loop for studying the recombination of the radiolytic gases in the steam phase. The preceding circuits, as well as others, return to a low pressure storage circuit. The cold water of the low pressure storage flask is continuously reintroduced into the high pressure main circuit by means of a return pump at a maximum head of 160 kg /cm 2 , and adjusted to the pressurizer level. This loop is also a testing bench for the tight high pressure apparatus. The circulating pump and the connecting flanges (Oak Ridge type) are water-tight. The feed pump and the pressure reducing valves are not; the un-tight ones have a system of leak recovery. To permanently check the tightness the circuit has been fitted with a leak detection system (similar to the HRT one). (author) [fr

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)

Common High Blood Pressure Myths

Science.gov (United States)

... Disease Venous Thromboembolism Aortic Aneurysm More Common High Blood Pressure Myths Updated:May 4,2018 Knowing the facts ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

Medications for High Blood Pressure

Science.gov (United States)

... Consumers Home For Consumers Consumer Updates Medications for High Blood Pressure Share Tweet Linkedin Pin it More sharing options ... age and you cannot tell if you have high blood pressure by the way you feel, so have your ...

High blood pressure and diet

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/007483.htm High blood pressure and diet To use the sharing features on ... diet is a proven way to help control high blood pressure . These changes can also help you lose weight ...

Solubility of natural gases in water under high pressure; Solubilite des gaz naturels dans l`eau a pression elevee

Energy Technology Data Exchange (ETDEWEB)

Dhima, A

1998-10-08

Under high pressure (up to 1200 bar) and high temperature (up to 200 deg C) petroleum reservoir conditions the hydrocarbon-water mutual solubilities may become important. Under such conditions, the prediction of hydrocarbon water solubilities is a challenge for petroleum engineers. Indeed, very few studies have been done ar pressures higher that 700 bars. New solubility data for methane, ethane, n-butane, CO{sub 2} and their mixtures in pure water were obtained at 344.25 K and from 2.5 to 100 MPa. The results agree very well with those of the literature in the case of pure hydrocarbons in water, but differ for the hydrocarbon mixtures. A rigorous thermodynamic analysis allows the elaboration of a model that combines a cubic equation of state (Peng-Robinson with k{sub ij} given in literature) with the Henry`s law approach. The (P,T) functional form of Henry`s constant is given by the Krichevsky-Kasarnovsky equation which involves two important parameters: partial molar volume at infinite dilution and Henry`s constant at the vapour pressure of water. For a given solute both parameters are only functions of temperature. A critical selection of binary solubility data for a large number of solutes has been used as a basis for a new correlation for calculating both this partial molar volume and the corresponding Henry`s constants as a function of temperature. (author) 169 refs.

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

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

Hydrogen production with fully integrated fuel cycle gas and vapour core reactors

International Nuclear Information System (INIS)

Anghaie, S.; Smith, B.

2004-01-01

This paper presents results of a conceptual design study involving gas and vapour core reactors (G/VCR) with a combined scheme to generate hydrogen and power. The hydrogen production schemes include high temperature electrolysis as well as two dominant thermochemical hydrogen production processes. Thermochemical hydrogen production processes considered in this study included the calcium-bromine process and the sulphur-iodine processes. G/VCR systems are externally reflected and moderated nuclear energy systems fuelled by stable uranium compounds in gaseous or vapour phase that are usually operated at temperatures above 1500 K. A gas core reactor with a condensable fuel such as uranium tetrafluoride (UF 4 ) or a mixture of UF 4 and other metallic fluorides (BeF 2 , LiF, KF, etc.) is commonly known as a vapour core reactor (VCR). The single most relevant and unique feature of gas/vapour core reactors is that the functions of fuel and coolant are combined into one. The reactor outlet temperature is not constrained by solid fuel-cladding temperature limits. The maximum fuel/working fluid temperature in G/VCR is only constrained by the reactor vessel material limits, which is far less restrictive than the fuel clad. Therefore, G/VCRs can potentially provide the highest reactor and cycle temperature among all existing or proposed fission reactor designs. Gas and vapour fuel reactors feature very low fuel inventory and fully integrated fuel cycle that provide for exceptional sustainability and safety characteristics. With respect to fuel utilisation, there is no fuel burn-up limit for gas core reactors due to continuous recycling of the fuel. Owing to the flexibility in nuclear design characteristics of cavity reactors, a wide range of conversion ratio from completely burner to breeder is achievable. The continuous recycling of fuel in G/VCR systems allow for complete burning of actinides without removing and reprocessing of the fuel. The only waste products at the back

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)

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.

Prediction of vapour-liquid equilibria for the kinetic study of processes based on synthesis gas

Energy Technology Data Exchange (ETDEWEB)

Di Serio, M.; Tesser, R.; Cozzolino, M.; Santacesaria, E. [Naples Univ., Napoli (Italy). Dept. of Chemistry

2006-07-01

Syngas is normally used in the production of a broad range of chemicals and fuels. In many of these processes multiphase reactors, gas-liquid or gas-liquid-solid are used. Kinetic studies in multiphase systems are often complicated by the non-ideal behaviour of reagents and/or products that are consistently partitioned between the liquid and the vapour phase. Moreover, as often kinetic data are collected in batch conditions for the liquid phase, activity coefficients of the partitioned components can consistently change during the time as a consequence of changing the composition of the reaction mixture. Therefore, it is necessary, in these cases, to known the vapor-liquid equilibria (VLE) in order to collect and to interpret correctly the kinetic data. The description of phase equilibria, at high pressures, is usually performed by means of an EOS (Equation of State) allowing the calculation of fugacity coefficients, for each component, in both phases and determining the partition coefficients but the EOS approach involves the experimental determination of the interaction parameters for all the possible binary system of the mixture. For multicomponent mixtures a complete experimental determination of vapourliquid equilibria is very hard, also considering the high pressure and temperatures used. Some predictive group contribution methods have been recently developed. In this paper, we will describe in detail the application of these methods to the methanol homologation, as an example, with the scope of determining more reliable kinetic parameters for this reaction. (orig.)

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.

Thermal plasma properties for Ar–Al, Ar–Fe and Ar–Cu mixtures used in welding plasmas processes: I. Net emission coefficients at atmospheric pressure

International Nuclear Information System (INIS)

Cressault, Y; Gleizes, A

2013-01-01

This article is devoted to the calculation of the net emission coefficient (NEC) of Ar–Al, Ar–Fe and Ar–Cu mixtures at atmospheric pressure for arc welding processes. The results are given in data tables for temperatures between 3 kK and 30 kK, for five plasma thicknesses (0, 0.5, 1, 2, 5 mm) and ten concentrations of metallic vapours (pure gas, 0.01%, 0.1%, 1%, 5%, 10%, 25%, 50%, 75% and pure metal vapours in mass proportions). The results are in good agreement with most of the works published on the subject for such mixtures. They highlight the influence of three parameters on the radiation of the plasma: the NEC is directly related to temperature and inversely related to plasma radius and is highly sensitive to the presence of metal vapours. Finally, numerical data are supplied in tables in order to develop accurate computational modelling of welding arc and to estimate both qualitatively and quantitatively the influence of each metallic vapour on the size and on the shape of the weld pool. (paper)

High pressure effects on fruits and vegetables

NARCIS (Netherlands)

Timmermans, R.A.H.; Matser, A.M.

2016-01-01

The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure

Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

Science.gov (United States)

Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

2015-07-03

The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

High-pressure high-temperature experiments: Windows to the Universe

International Nuclear Information System (INIS)

Santaria-Perez, D.

2011-01-01

From Earth compositional arguments suggested by indirect methods, such as the propagation of seismic waves, is possible to generate in the laboratory pressure and temperature conditions similar to those of the Earth or other planet interiors and to study how these conditions affect to a certain metal or mineral. These experiments are, therefore, windows to the Universe. The aim of this chapter is to illustrate the huge power of the experimental high-pressure high-temperature techniques and give a global overview of their application to different geophysical fields. Finally, we will introduce the MALTA Consolider Team, which gather most of the Spanish high-pressure community, and present their available high-pressure facilities. (Author) 28 refs.

Mixture distribution in a multi-valve twin-spark ignition engine equipped with high-pressure multi-hole injectors

International Nuclear Information System (INIS)

Mitroglou, N; Arcoumanis, C; Mori, K; Motoyama, Y

2006-01-01

Laser-induced fluorescence has been mainly used to characterise the two-dimensional fuel vapour concentration inside the cylinder of a multi-valve twin-spark ignition engine equipped with high-pressure multi-hole injectors. The effects of injection timing, in-cylinder charge motion and injector tip layout have been quantified. The flexibility in nozzle design of the multi-hole injectors has proven to be a powerful tool in terms of matching overall spray cone angle and number of holes to specific engine configurations. Injection timing was found to control spray impingement on the piston and cylinder wall, thus contributing to quick and efficient fuel evaporation. It was confirmed that in-cylinder charge motion plays a major role in engine's stable operation by assisting in the transportation of the air-fuel mixture towards the ignition locations (i.e. spark-plugs) in the way of a uniformly distributed charge or by preserving stratification of the charge depending on operating mode of the engine

Nuclear magnetic resonance studies at high pressures

International Nuclear Information System (INIS)

Jonas, J.

1980-01-01

Recent advances in the field of NMR spectroscopy at high pressure are reviewed. After a brief discussion of two novel experimental techniques, the main focus of this review is on several specific studies which illustrate the versatility and power of this high pressure field. Experimental aspects of NMR measurements at high pressure and high temperature and the techniques for the high resolution NMR spectroscopy at high pressure are discussed. An overview of NMR studies of the dynamic structure of simple polyatomic liquids and hydrogen bonded liquids is followed by a discussion of high resolution spectroscopy at high pressure. Examples of NMR studies of disordered organic solids and polymers conclude the review. (author)

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.)

High pressure effects on fruits and vegetables

OpenAIRE

Timmermans, R.A.H.; Matser, A.M.

2016-01-01

The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure treatment can be used for product modification through pressure gelatinization of starch and pressure denaturation of proteins. Key pressure–thermal treatment effects on vitamin, enzymes, flavor, co...

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.

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 ...

High-temperature, Knudsen cell-mass spectroscopic studies on lanthanum oxide/uranium dioxide solid solutions

International Nuclear Information System (INIS)

Sunder, S.; McEachern, R.; LeBlanc, J.C.

2001-01-01

Knudsen cell-mass spectroscopic experiments were carried out with lanthanum oxide/uranium oxide solid solutions (1%, 2% and 5% (metal at.% basis)) to assess the volatilization characteristics of rare earths present in irradiated nuclear fuel. The oxidation state of each sample used was conditioned to the 'uranium dioxide stage' by heating in the Knudsen cell under an atmosphere of 10% CO 2 in CO. The mass spectra were analyzed to obtain the vapour pressures of the lanthanum and uranium species. It was found that the vapour pressure of lanthanum oxide follows Henry's law, i.e., its value is directly proportional to its concentration in the solid phase. Also, the vapour pressure of lanthanum oxide over the solid solution, after correction for its concentration in the solid phase, is similar to that of uranium dioxide. (authors)

High Blood Pressure - Multiple Languages

Science.gov (United States)

... Being 8 - High Blood Pressure - Amarɨñña / አማርኛ (Amharic) MP3 Siloam Family Health Center Arabic (العربية) Expand Section ... Being 8 - High Blood Pressure - myanma bhasa (Burmese) MP3 Siloam Family Health Center Chinese, Simplified (Mandarin dialect) ( ...

Utility of DMSP-SSM/I for integrated water vapour over the Indian seas

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging Solutions)

Recent algorithms for Special Sensor Microwave/Imager (DMSP-SSM/I) satellite data are used for estimating integrated water vapour over the Indian seas. Integrated water vapour obtained from these algorithms is compared with that derived from radiosonde observations at Minicoy and Port. Blair islands. Algorithm-3 of ...

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.

On the pressure drop in Plate Heat Exchangers used as desorbers in absorption chillers

International Nuclear Information System (INIS)

Garcia-Hernando, N.; Almendros-Ibanez, J.A.; Ruiz, G.; Vega, M. de

2011-01-01

The influence of the pressure drop in Plate Heat Exchangers (PHE) in the boiling temperature of LiBr-H 2 O and NH 3 -H 2 O solutions is studied. For the NH 3 -H 2 O solution, the pressure drop-temperature saturation relationship estates that high pressure drops can be allowed in the solution with negligible changes in the saturation temperature, and in the PHE performance. Besides, in the case of the LiBr-H 2 O solution, as the working pressure is usually very low, the analysis of the pressure drop must be taken as a main limiting parameter for the use of Plate Heat Exchangers as vapour generators. In this case, the pressure drop may considerably change the boiling temperature of the solution entering the heat exchanger and therefore a higher heating fluid temperature may be required. A guideline to design these systems is proposed.

Anxiety: A Cause of High Blood Pressure?

Science.gov (United States)

... of high blood pressure? Can anxiety cause high blood pressure? Answers from Sheldon G. Sheps, M.D. Anxiety doesn't cause long-term high blood pressure (hypertension). But episodes of anxiety can cause dramatic, ...

Water vapour solubility and conductivity study of the proton conductor BaCe(0.9 − x)ZrxY0.1O(3 − δ)

DEFF Research Database (Denmark)

Ricote, Sandrine; Bonanos, Nikolaos; Caboche, G:

2009-01-01

The perovskite BaCe(0.9 − x)ZrxY0.1O(3 − δ) has been prepared by solid state reaction at 1400 °C and conventional sintering at 1700 °C. Water uptake experiments performed between 400 and 600 °C, at a water vapour pressure of 0.02 atm, provide data on the concentration of protons incorporated in t...

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

Science.gov (United States)

2010-10-01

... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

High-Performance Pressure Sensor for Monitoring Mechanical Vibration and Air Pressure

Directory of Open Access Journals (Sweden)

Yancheng Meng

2018-05-01

Full Text Available To realize the practical applications of flexible pressure sensors, the high performance (sensitivity and response time as well as more functionalities are highly desired. In this work, we fabricated a piezoresistive pressure sensor based on the micro-structured composites films of multi-walled carbon nanotubes (MWCNTs and poly (dimethylsiloxane (PDMS. In addition, we establish efficient strategies to improve key performance of our pressure sensor. Its sensitivity is improved up to 474.13 kPa−1 by minimizing pressure independent resistance of sensor, and response time is shorten as small as 2 μs by enhancing the elastic modulus of polymer elastomer. Benefiting from the high performance, the functionalities of sensors are successfully extended to the accurate detection of high frequency mechanical vibration (~300 Hz and large range of air pressure (6–101 kPa, both of which are not achieved before.

Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

Science.gov (United States)

Cieśla, Jolanta; Sokołowska, Zofia; Witkowska-Walczak, Barbara; Skic, Kamil

2018-01-01

Water vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0-1 range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

Regularities of growth, condensation, solution of vapour and gaseous bubbles in turbulent flows

International Nuclear Information System (INIS)

Avdeev, A.A.

1988-01-01

Corrections for interphase transfer exchange intensity and for bubbles dynamics in the forced turbulent flow as well are obtained on the basis of the surface periodical restoration model. Analysis of the effects, caused by turbulence additional generation due to bubbles floating-up within gravity field, is carried out. Formulae for calculating interphase heat and mass transfer at bubbling are suggested. Application limits for the developed model are determined. Comparison of calculation results according to the derived universal dependence with experimental data on growth rates and condensation of vapour bubble, and on solution rates of gaseous bubbles in water (Re=8x10 3 -2x10 6 ; Pr0.83-568, pressure up to 10 MPa) has revealed their good agreeme nt

Terbium oxide at high pressures

International Nuclear Information System (INIS)

Dogra, Sugandha; Sharma, Nita Dilawar; Singh, Jasveer; Bandhyopadhyay, A.K.

2011-01-01

In this work we report the behaviour of terbium oxide at high pressures. The as received sample was characterized at ambient by X-ray diffraction and Raman spectroscopy. The X-ray diffraction showed the sample to be predominantly cubic Tb 4 O 7 , although a few peaks also match closely with Tb 2 O 3 . In fact in a recent study done on the same sample, the sample has been shown to be a mixture of Tb 4 O 7 and Tb 2 O 3 . The sample was subjected to high pressures using a Mao-Bell type diamond anvil cell upto a pressure of about 42 GPa with ruby as pressure monitor

High-pressure phase transitions of strontianite

Science.gov (United States)

Speziale, S.; Biedermann, N.; Reichmann, H. J.; Koch-Mueller, M.; Heide, G.

2015-12-01

Strontianite (SrCO3) is isostructural to aragonite, a major high-pressure polymorph of calcite. Thus it is a material of interest to investigate the high-pressure phase behavior of aragonite-group minerals. SrCO3 is a common component of natural carbonates and knowing its physical properties at high pressures is necessary to properly model the thermodynamic properties of complex carbonates, which are major crustal minerals but are also present in the deep Earth [Brenker et al., 2007] and control carbon cycling in the Earth's mantle. The few available high-pressure studies of SrCO3 disagree regarding both pressure stability and structure of the post-aragonite phase [Lin & Liu, 1997; Ono et al., 2005; Wang et al. 2015]. To clarify such controversies we investigated the high-pressure behavior of synthetic SrCO3 by Raman spectroscopy. Using a diamond anvil cell we compressed single-crystals or powder of strontianite (synthesized at 4 GPa and 1273 K for 24h in a multi anvil apparatus), and measured Raman scattering up to 78 GPa. SrCO3 presents a complex high-pressure behavior. We observe mode softening above 20 GPa and a phase transition at 25 - 26.9 GPa, which we interpret due to the CO3 groups rotation, in agreement with Lin & Liu [1997]. The lattice modes in the high-pressure phase show dramatic changes which may indicate a change from 9-fold coordinated Sr to a 12-fold-coordination [Ono, 2007]. Our results confirm that the high-pressure phase of strontianite is compatible with Pmmn symmetry. References Brenker, F.E. et al. (2007) Earth and Planet. Sci. Lett., 260, 1; Lin, C.-C. & Liu, L.-G. (1997) J. Phys. Chem. Solids, 58, 977; Ono, S. et al. (2005) Phys. Chem. Minerals, 32, 8; Ono, S. (2007) Phys. Chem. Minerals, 34, 215; Wang, M. et al. (2015) Phys Chem Minerals 42, 517.

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

Pressure suppression system for a nuclear reactor

International Nuclear Information System (INIS)

Jost, N.

1977-01-01

The invention pertains to a pressure suppression system for PWR reactors where the parts enclosing the primary coolant are contained in two pressure-tight separate chambers. According to the invention, these chambers are partly filled with water and are connected with each other below the water surface. This way, gases cannot escape from the containment, not even if a valve and a line are damaged at the same time, as the vapours released condensate in the water of at least one of the other chambers. (HP) [de

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

Nicotine content of electronic cigarettes, its release in vapour and its consistency across batches: regulatory implications.

Science.gov (United States)

Goniewicz, Maciej L; Hajek, Peter; McRobbie, Hayden

2014-03-01

Electronic cigarettes (EC) may have a potential for public health benefit as a safer alternative to smoking, but questions have been raised about whether EC should be licensed as a medicine, with accurate labelling of nicotine content. This study determined the nicotine content of the cartridges of the most popular EC brands in the United Kingdom and the nicotine levels they deliver in the vapour, and estimated the safety and consistency of nicotine delivery across batches of the same product as a proxy for quality control for individual brands and within the industry. We studied five UK brands (six products) with high internet popularity. Two samples of each brand were purchased 4 weeks apart, and analysed for nicotine content in the cartridges and nicotine delivery in vapour. The nicotine content of cartridges within the same batch varied by up to 12% relative standard deviation (RSD) and the mean difference between different batches of the same brand ranged from 1% [95% confidence interval (CI) = -5 to 7%] to 20% (95% CI=14-25%) for five brands and 31% (95% CI=21-39%) for the sixth. The puffing schedule used in this study vaporized 10-81% of the nicotine present in the cartridges. The nicotine delivery from 300 puffs ranged from ∼2 mg to ∼15 mg and was not related significantly to the variation of nicotine content in e-liquid (r=0.06, P=0.92). None of the tested products allowed access to e-liquid or produced vapour nicotine concentrations as high as conventional cigarettes. There is very little risk of nicotine toxicity from major electronic cigarette (EC) brands in the United Kingdom. Variation in nicotine concentration in the vapour from a given brand is low. Nicotine concentration in e-liquid is not well related to nicotine in vapour. Other EC brands may be of lower quality and consumer protection regulation needs to be implemented, but in terms of accuracy of labelling of nicotine content and risks of nicotine overdose, regulation over and above

High-Pressure Polymorphism in Orthoamphiboles

Science.gov (United States)

Finkelstein, G. J.; Zhang, D.; Shelton, H.; Dera, P.

2017-12-01

Amphiboles are double-chain silicate minerals that are the structurally hydrated counterpart to single-chain, anhydrous pyroxenes. They may play an important role in the earth as a carrier for volatiles in subduction zones, as well as a generator for seismic anisotropy in the upper mantle. Recent work has described previously unrecognized high-pressure polymorphism at low temperatures in a variety of pyroxene minerals, which may be relevant for the structure and dynamics of thick, cold, subducted slabs. However, high-pressure polymorphism in amphiboles above a few GPa in pressure has not been well explored, and if similar polymorphism to pyroxenes exists in this mineral family, it may affect the extent and depth of volatile transport in amphiboles, as well as their rheological properties. At low temperatures and high pressures, orthopyroxenes undergo crystal structure transitions at lower pressures than clinopyroxenes (10-30 GPa vs. > 50 GPa), so for this study we have investigated polymorphism in the anthophyllite-gedrite (Al-free and Al rich) orthoamphibole solid solution series. Using neon gas-loaded diamond anvil cells, we compressed both phases to a maximum pressure of 31 GPa, and observed transitions to new monoclinic structures in both endmembers. In this presentation, we will discuss the details of these transitions and implications for the earth's interior.

Application and possible benefits of high hydrostatic pressure or high-pressure homogenization on beer processing: A review.

Science.gov (United States)

Santos, Lígia Mr; Oliveira, Fabiano A; Ferreira, Elisa Hr; Rosenthal, Amauri

2017-10-01

Beer is the most consumed beverage in the world, especially in countries such as USA, China and Brazil.It is an alcoholic beverage made from malted cereals, and the barley malt is the main ingredient, added with water, hops and yeast. High-pressure processing is a non-traditional method to preserve food and beverages. This technology has become more interesting compared to heat pasteurization, due to the minimal changes it brings to the original nutritional and sensory characteristics of the product, and it comprises two processes: high hydrostatic pressure, which is the most industrially used process, and high-pressure homogenization. The use of high pressure almost does not affect the molecules that are responsible for the aroma and taste, pigments and vitamins compared to the conventional thermal processes. Thus, the products processed by high-pressure processing have similar characteristics compared to fresh products, including beer. The aim of this paper was to review what has been investigated about beer processing using this technology regarding the effects on physicochemical, microbiology and sensory characteristics and related issues. It is organized by processing steps, since high pressure can be applied to malting, mashing, boiling, filtration and pasteurization. Therefore, the beer processed with high-pressure processing may have an extended shelf-life because this process can inactivate beer spoilage microorganisms and result in a superior sensory quality related to freshness and preservation of flavors as it does to juices that are already commercialized. However, beyond this application, high-pressure processing can modify protein structures, such as enzymes that are present in the malt, like α- and β-amylases. This process can activate enzymes to promote, for example, saccharification, or instead inactivate at the end of mashing, depending on the pressure the product is submitted, besides being capable of isomerizing hops to raise beer bitterness

Surface polish of PLA parts in FDM using dichloromethane vapour

Directory of Open Access Journals (Sweden)

Jin Yifan

2017-01-01

Full Text Available Fused deposition modelling has become one of the most diffused rapid prototyping techniques, which is widely used to fabricate prototypes. However, further application of this technology is severely limited by poor surface roughness. Thus it is necessary to adopt some operations to improve surface quality. Chemical finishing is typically employed to finish parts in fused deposition modelling (FDM. The purpose of this paper is to decrease the surface roughness for polylactic acid (PLA parts in FDM. The chemical reaction mechanism during the treating process is analysed. Then NaOH solution and dichloromethane vapour are used to treat FDM specimens respectively. A 3D laser microscope has been applied to assess the effects in terms of surface topography and roughness. The experimental results show that treatment using dichloromethane vapour performs much better than NaOH solution. Compared with the untreated group, surface roughness obtained through vapour treatment decreases by 88 per cent. This research has been conducted to provide a better method to treat PLA parts using chemical reagents.

High Blood Pressure: Medicines to Help You

Science.gov (United States)

... For Consumers Consumer Information by Audience For Women High Blood Pressure--Medicines to Help You Share Tweet Linkedin Pin ... Click here for the Color Version (PDF 533KB) High blood pressure is a serious illness. High blood pressure is ...

High-pressure oxidation of methane

DEFF Research Database (Denmark)

Hashemi, Hamid; Christensen, Jakob Munkholt; Gersen, Sander

2016-01-01

Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly...... diluted in nitrogen. It was found that under the investigated conditions, the onset temperature for methane oxidation ranged from 723 K under reducing conditions to 750 K under stoichiometric and oxidizing conditions. The RCM experiments were carried out at pressures of 15–80 bar and temperatures of 800......–1250 K under stoichiometric and fuel-lean (Φ=0.5) conditions. Ignition delays, in the range of 1–100 ms, decreased monotonically with increasing pressure and temperature. A chemical kinetic model for high-pressure methane oxidation was established, with particular emphasis on the peroxide chemistry...

Advances in high pressure science and technology: proceedings of the fourth national conference on high pressure science and technology

International Nuclear Information System (INIS)

Yousuf, Mohammad; Subramanian, N.; Govinda Rajan, K.

1997-09-01

The proceedings of the fourth National Conference on High Pressure Science and Technology covers a wide area of research and development activities in the field of high pressure science and technology, broadly classified into the following themes: mechanical behaviour of materials; instrumentation and methods in high pressure research; pressure calibration, standards and safety aspects; phase transitions; shock induced reactions; mineral science, geophysics, geochemistry and planetary sciences; optical, electronic and transport properties; synthesis of materials; soft condensed matter physics and liquid crystals; computational methods in high pressure research. Papers relevant to INIS are indexed separately

Synthesis and characterization of Bi.sub.1-x./sub.Nd.sub.x./sub.FeO.sub.3./sub. thin films deposited using a high throughput physical vapour deposition technique

Czech Academy of Sciences Publication Activity Database

Darby, M.S.B.; Karpinsky, D.V.; Pokorný, Jan; Guerin, D.; Kholkin, A. L.; Miao, S.; Haydn, B.E.; Reaney, I. M.

2013-01-01

Roč. 531, MAR (2013), s. 56-60 ISSN 0040-6090 Institutional support: RVO:68378271 Keywords : bismuth ferrite * piezoelectric * neodymium doped * high throughput * combinatorial * physical vapour deposition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.867, year: 2013 http://www.sciencedirect.com/science/article/pii/S004060901201646X

Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

Science.gov (United States)

Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

2016-01-01

A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

Application of High Pressure in Food Processing

Directory of Open Access Journals (Sweden)

Herceg, Z.

2011-01-01

Full Text Available In high pressure processing, foods are subjected to pressures generally in the range of 100 – 800 (1200 MPa. The processing temperature during pressure treatments can be adjusted from below 0 °C to above 100 °C, with exposure times ranging from a few seconds to 20 minutes and even longer, depending on process conditions. The effects of high pressure are system volume reduction and acceleration of reactions that lead to volume reduction. The main areas of interest regarding high-pressure processing of food include: inactivation of microorganisms, modification of biopolymers, quality retention (especially in terms of flavour and colour, and changes in product functionality. Food components responsible for the nutritive value and sensory properties of food remain unaffected by high pressure. Based on the theoretical background of high-pressure processing and taking into account its advantages and limitations, this paper aims to show its possible application in food processing. The paper gives an outline of the special equipment used in highpressure processing. Typical high pressure equipment in which pressure can be generated either by direct or indirect compression are presented together with three major types of high pressure food processing: the conventional (batch system, semicontinuous and continuous systems. In addition to looking at this technology’s ability to inactivate microorganisms at room temperature, which makes it the ultimate alternative to thermal treatments, this paper also explores its application in dairy, meat, fruit and vegetable processing. Here presented are the effects of high-pressure treatment in milk and dairy processing on the inactivation of microorganisms and the modification of milk protein, which has a major impact on rennet coagulation and curd formation properties of treated milk. The possible application of this treatment in controlling cheese manufacture, ripening and safety is discussed. The opportunities

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

Directory of Open Access Journals (Sweden)

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

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.

Different physiological and behavioural effects of e-cigarette vapour and cigarette smoke in mice.

Science.gov (United States)

Ponzoni, L; Moretti, M; Sala, M; Fasoli, F; Mucchietto, V; Lucini, V; Cannazza, G; Gallesi, G; Castellana, C N; Clementi, F; Zoli, M; Gotti, C; Braida, D

2015-10-01

Nicotine is the primary addictive substance in tobacco smoke and electronic cigarette (e-cig) vapour. Methodological limitations have made it difficult to compare the role of the nicotine and non-nicotine constituents of tobacco smoke. The aim of this study was to compare the effects of traditional cigarette smoke and e-cig vapour containing the same amount of nicotine in male BALB/c mice exposed to the smoke of 21 cigarettes or e-cig vapour containing 16.8 mg of nicotine delivered by means of a mechanical ventilator for three 30-min sessions/day for seven weeks. One hour after the last session, half of the animals were sacrificed for neurochemical analysis, and the others underwent mecamylamine-precipitated or spontaneous withdrawal for the purposes of behavioural analysis. Chronic intermittent non-contingent, second-hand exposure to cigarette smoke or e-cig vapour led to similar brain cotinine and nicotine levels, similar urine cotinine levels and the similar up-regulation of α4β2 nicotinic acetylcholine receptors in different brain areas, but had different effects on body weight, food intake, and the signs of mecamylamine-precipitated and spontaneous withdrawal episodic memory and emotional responses. The findings of this study demonstrate for the first time that e-cig vapour induces addiction-related neurochemical, physiological and behavioural alterations. The fact that inhaled cigarette smoke and e-cig vapour have partially different dependence-related effects indicates that compounds other than nicotine contribute to tobacco dependence. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

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.

Effect of Organic Vapour on Porous Alumina Based Moisture Sensor in Dry Gases

Directory of Open Access Journals (Sweden)

Saakshi DHANEKAR

2009-08-01

Full Text Available A capacitive porous alumina based trace moisture sensor in the range of 50 to 500 ppm (V was fabricated by low cost sol-gel technique. The cross-sensitivities due to the presence of organic vapours like ethanol, methanol, acetone and benzene were studied. The change in response and recovery time with ppm for moisture sensing was also calculated. The experimental results conclude that moisture sensor is responsive to the polar organic vapours but has almost negligible response to the nonpolar molecules like benzene. Response of the sensor to the organic vapours as compared to the moisture sensitivity is very less. The effect of ambient temperature was found to be negligible.

Direct dimethyl ether high temperature polymer electrolyte membrane fuel cells

DEFF Research Database (Denmark)

Vassiliev, Anton; Jensen, Jens Oluf; Li, Qingfeng

and suffers from low DME solubility in water. When the DME - water mixture is fed as vapour miscibility is no longer a problem. The increased temperature is more beneficial for the kinetics of the direct oxidation of DME than of methanol. The Open Circuit Voltage (OCV) with DME operation was 50 to 100 m......A high temperature polybenzimidazole (PBI) polymer fuel cell was fed with dimethyl ether (DME) and water vapour mixture on the anode at ambient pressure with air as oxidant. A peak power density of 79 mW/cm2 was achieved at 200°C. A conventional polymer based direct DME fuel cell is liquid fed......V higher than that of methanol, indicating less fuel crossover....

High Blood Pressure

Science.gov (United States)

... factors Diabetes High blood pressure Family history Obesity Race/ethnicity Full list of causes and risk factors ... give Give monthly Memorials and tributes Donate a car Donate gently used items Stock donation Workplace giving ...

High Blood Pressure

Science.gov (United States)

... kidney disease, diabetes, or metabolic syndrome Read less Unhealthy lifestyle habits Unhealthy lifestyle habits can increase the risk of high blood pressure. These habits include: Unhealthy eating patterns, such as eating too much sodium ...

Chemical vapour deposition of vanadium oxide thermochromic thin films

Science.gov (United States)

Piccirillo, Clara

Thermochromic materials change optical properties, such as transmittance or reflectance, with a variation in temperature. An ideal intelligent (smart) material will allow solar radiation in through a window in cold conditions, but reflect that radiation in warmer conditions. The variation in the properties is often associated with a phase change, which takes place at a definite temperature, and is normally reversible. Such materials are usually applied to window glass as thin films. This thesis presents the work on the development of thermochromic vanadium (IV) oxide (VO2) thin films - both undoped and doped with tungsten, niobium and gold nanoparticles - which could be employed as solar control coatings. The films were deposited using Chemical Vapour Deposition (CVD), using improved Atmospheric Pressure (APCVD), novel Aerosol Assisted (AACVD) and novel hybrid AP/AACVD techniques. The effects of dopants on the metalto- semiconductor transition temperature and transmittance/reflectance characteristics were also investigated. This work significantly increased the understanding of the mechanisms behind thermochromic behaviour, and resulted in thermochromic materials based on VO2 with greatly improved properties.

Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites.

Science.gov (United States)

Kierys, Agnieszka; Krasucka, Patrycja; Grochowicz, Marta

2017-11-01

The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS). The polymers selected for this study were poly(TRIM) and poly(HEMA- co -TRIM) produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM)-IBS and/or poly(HEMA- co -TRIM)-IBS) with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites

Directory of Open Access Journals (Sweden)

Agnieszka Kierys

2017-11-01

Full Text Available The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS. The polymers selected for this study were poly(TRIM and poly(HEMA-co-TRIM produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM-IBS and/or poly(HEMA-co-TRIM-IBS with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

The magnetic vapour shield effect at divertor plates during plasma disruptions

International Nuclear Information System (INIS)

Piazza, G.; Goel, B.; Hoebel, W.; Wuerz, H.; Landman, I.

1995-01-01

Hard disruptions in a TOKAMAK cause a large thermal load on the divertor plates with an instantaneous ablation of a part of the heated material. The produced vapour cloud screens the plasma facing component from the direct interaction with the disrupting plasma (vapour shield effect). In order to quantify the damage to the divertor the magneto-hydrodynamic behaviour of the expanding vapour cloud has been investigated using an extended version of the 1-dimensional Lagrangian hydrodynamic code KATACO. Modelling of the magnetic field effects on the expanding plasma takes into account that the magnetic field is oblique to the divertor (1 1/2 dimensional model). The ''Radiation Heat Conduction Approximation'' has been used for describing the radiative energy transport. In this paper results are presented assuming graphite as divertor material, irradiated with a proton beam of an energy density of 12MJ/m 2 and a duration of 100μs. (orig.)

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour.

Science.gov (United States)

Martin, T L; Coe, C; Bagot, P A J; Morrall, P; Smith, G D W; Scott, T; Moody, M P

2016-07-12

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

Science.gov (United States)

Martin, T. L.; Coe, C.; Bagot, P. A. J.; Morrall, P.; Smith, G. D. W.; Scott, T.; Moody, M. P.

2016-07-01

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (~5 nm) interfacial layer of uranium hydride was observed at the oxide-metal interface. Exposure to deuterated water vapour produced an equivalent deuteride signal at the metal-oxide interface, confirming the hydride as originating via the water vapour oxidation mechanism. Hydroxide ions were detected uniformly throughout the oxide, yet showed reduced prominence at the metal interface. These results support a proposed mechanism for the oxidation of uranium in water vapour environments where the transport of hydroxyl species and the formation of hydride are key to understanding the observed behaviour.

Evolution of polarization in an atomic vapour with negative refractive index

International Nuclear Information System (INIS)

Zhuang Fei; Shen Jianqi

2006-01-01

A three-level Lambda-configuration atomic vapour may exhibit simultaneously negative permittivity and permeability in the optical frequency band, and an isotropic left-handed vapour medium could therefore be realized within the framework of quantum optics. One of the most remarkable features of the present scheme is that both the refractive index and the photon helicity reversal inside the vapour can be controllably manipulated by an external coupling light field. The phenomenological Hamiltonian that describes the process of helicity reversal is constructed and the time-dependent Schroedinger equation governing the time evolution of the polarization states of the lightwave is solved by means of the Lewis-Riesenfeld invariant theory. The transition between the polarization states (and hence the accompanied photon helicity reversal), which is exactly analogous to the transition operation between bits in digital circuit, may be valuable for the development of new techniques in quantum optics and would have potential applications in information technology

MEDUSA: The ExoMars experiment for in-situ monitoring of dust and water vapour

Science.gov (United States)

Colangeli, L.; Lopez-Moreno, J. J.; Nørnberg, P.; Della Corte, V.; Esposito, F.; Mazzotta Epifani, E.; Merrison, J.; Molfese, C.; Palumbo, P.; Rodriguez-Gomez, J. F.; Rotundi, A.; Visconti, G.; Zarnecki, J. C.; The International Medusa Team

2009-07-01

Dust and water vapour are fundamental components of the Martian atmosphere. In view of tracing the past environmental conditions on Mars, that possibly favoured the appearing of life forms, it is important to study the present climate and its evolution. Here dust and water vapour have (and have had) strong influence. Of major scientific interest is the quantity and physical, chemical and electrical properties of dust and the abundance of water vapour dispersed in the atmosphere and their exchange with the surface. Moreover, in view of the exploration of the planet with automated systems and in the future by manned missions, it is of primary importance to analyse the hazards linked to these environmental factors. The Martian Environmental Dust Systematic Analyser (MEDUSA) experiment, included in the scientific payload of the ESA ExoMars mission, accommodates a complement of sensors, based on optical detection and cumulative mass deposition, that aims to study dust and water vapour in the lower Martian atmosphere. The goals are to study, for the first time, in-situ and quantitatively, physical properties of the airborne dust, including the cumulative dust mass flux, the dust deposition rate, the physical and electrification properties, the size distribution of sampled particles and the atmospheric water vapour abundance versus time.

High-pressure system for Compton scattering experiments

International Nuclear Information System (INIS)

Oomi, G.; Honda, F.; Kagayama, T.; Itoh, F.; Sakurai, H.; Kawata, H.; Shimomura, O.

1998-01-01

High-pressure apparatus for Compton scattering experiments has been developed to study the momentum distribution of conduction electrons in metals and alloys at high pressure. This apparatus was applied to observe the Compton profile of metallic Li under pressure. It was found that the Compton profile at high pressure could be obtained within several hours by using this apparatus and synchrotron radiation. The result on the pressure dependence of the Fermi momentum of Li obtained here is in good agreement with that predicted from the free-electron model

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 %.

High-pressure applications in medicine and pharmacology

Energy Technology Data Exchange (ETDEWEB)

Silva, Jerson L; Foguel, Debora; Suarez, Marisa; Gomes, Andre M O; Oliveira, Andrea C [Centro Nacional de Ressonancia Magnetica Nuclear, Departamento de Bioquimica Medica, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590 (Brazil)

2004-04-14

High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic.

High-pressure applications in medicine and pharmacology

International Nuclear Information System (INIS)

Silva, Jerson L; Foguel, Debora; Suarez, Marisa; Gomes, Andre M O; Oliveira, Andrea C

2004-01-01

High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic

Probabilistic risk assessment for six vapour intrusion algorithms

NARCIS (Netherlands)

Provoost, J.; Reijnders, L.; Bronders, J.; Van Keer, I.; Govaerts, S.

2014-01-01

A probabilistic assessment with sensitivity analysis using Monte Carlo simulation for six vapour intrusion algorithms, used in various regulatory frameworks for contaminated land management, is presented here. In addition a deterministic approach with default parameter sets is evaluated against

What Is High Blood Pressure Medicine?

Science.gov (United States)

... a medicine calendar. • Set a reminder on your smartphone. What types of medicine may be prescribed? One ... High Blood Pressure Medicine? What are their side effects? For many people, high blood pressure medicine can ...

High Blood Pressure in Pregnancy

Science.gov (United States)

... of the baby. Controlling your blood pressure during pregnancy and getting regular prenatal care are important for ... your baby. Treatments for high blood pressure in pregnancy may include close monitoring of the baby, lifestyle ...

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

On the pressure drop in Plate Heat Exchangers used as desorbers in absorption chillers

Energy Technology Data Exchange (ETDEWEB)

Garcia-Hernando, N.; de Vega, M. [Energy System Engineering (ISE), Departamento de Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad, 30, 28911 Leganes, Madrid (Spain); Almendros-Ibanez, J.A. [Escuela de Ingenieros Industriales de Albacete, Departamento de Mecanica Aplicada e Ingenieria de Proyectos, Universidad de Castilla La Mancha, Campus Universitario s/n, 02071 Albacete (Spain); Renewable Energy Research Institute, c/de la Investigacion s/n, 02071 Albacete (Spain); Ruiz, G. [Energy Efficiency and Renewables Department, Tecnicas Reunidas S.A., C/Arapiles No. 13, 10a, 28015 Madrid (Spain)

2011-02-15

The influence of the pressure drop in Plate Heat Exchangers (PHE) in the boiling temperature of LiBr-H{sub 2}O and NH{sub 3}-H{sub 2}O solutions is studied. For the NH{sub 3}-H{sub 2}O solution, the pressure drop-temperature saturation relationship estates that high pressure drops can be allowed in the solution with negligible changes in the saturation temperature, and in the PHE performance. Besides, in the case of the LiBr-H{sub 2}O solution, as the working pressure is usually very low, the analysis of the pressure drop must be taken as a main limiting parameter for the use of Plate Heat Exchangers as vapour generators. In this case, the pressure drop may considerably change the boiling temperature of the solution entering the heat exchanger and therefore a higher heating fluid temperature may be required. A guideline to design these systems is proposed. (author)

On high-pressure melting of tantalum

Science.gov (United States)

Luo, Sheng-Nian; Swift, Damian C.

2007-01-01

The issues related to high-pressure melting of Ta are discussed within the context of diamond-anvil cell (DAC) and shock wave experiments, theoretical calculations and common melting models. The discrepancies between the extrapolations of the DAC melting curve and the melting point inferred from shock wave experiments, cannot be reconciled either by superheating or solid-solid phase transition. The failure to reproduce low-pressure DAC melting curve by melting models such as dislocation-mediated melting and the Lindemann law, and molecular dynamics and quantum mechanics-based calculations, undermines their predictions at moderate and high pressures. Despite claims to the contrary, the melting curve of Ta (as well as Mo and W) remains inconclusive at high pressures.

Density profiles and collective excitations of a trapped two-component Fermi vapour

International Nuclear Information System (INIS)

Amoruso, M.; Meccoli, I.; Minguzzi, A.; Tosi, M.P.

1999-08-01

We discuss the ground state and the small-amplitude excitations of a degenerate vapour of fermionic atoms placed in two hyperfine states inside a spherical harmonic trap. An equations-of-motion approach is set up to discuss the hydrodynamic dissipation processes from the interactions between the two components of the fluid beyond mean-field theory and to emphasize analogies with spin dynamics and spin diffusion in a homogeneous Fermi liquid. The conditions for the establishment of a collisional regime via scattering against cold-atom impurities are analyzed. The equilibrium density profiles are then calculated for a two-component vapour of 40 K atoms: they are little modified by the interactions for presently relevant values of the system parameters, but spatial separation of the two components will spontaneously arise as the number of atoms in the trap is increased. The eigenmodes of collective oscillation in both the total particle number density and the concentration density are evaluated analytically in the special case of a symmetric two-component vapour in the collisional regime. The dispersion relation of the surface modes for the total particle density reduces in this case to that of a one-component Fermi vapour, whereas the frequencies of all other modes are shifted by the interactions. (author)

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

Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

Directory of Open Access Journals (Sweden)

Zengling Ran

2014-08-01

Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure.

Science.gov (United States)

Ran, Zengling; Liu, Shan; Liu, Qin; Huang, Ya; Bao, Haihong; Wang, Yanjun; Luo, Shucheng; Yang, Huiqin; Rao, Yunjiang

2014-08-07

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

Techniques in high pressure neutron scattering

CERN Document Server

Klotz, Stefan

2013-01-01

Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

High blood pressure and eye disease

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/000999.htm High blood pressure and eye disease To use the sharing features on this page, please enable JavaScript. High blood pressure can damage blood vessels in the retina . The ...

Magnetic and Superconducting Materials at High Pressures

Energy Technology Data Exchange (ETDEWEB)

Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

2015-03-24

The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

High Blood Pressure: Unique to Older Adults

Science.gov (United States)

... our e-newsletter! Aging & Health A to Z High Blood Pressure Hypertension Unique to Older Adults This section provides ... Pressure Targets are Different for Very Old Adults High blood pressure (also called hypertension) increases your chance of having ...

Transportable, small high-pressure preservation vessel for cells

International Nuclear Information System (INIS)

Kamimura, N; Sotome, S; Shimizu, A; Nakajima, K; Yoshimura, Y

2010-01-01

We have previously reported that the survival rate of astrocytes increases under high-pressure conditions at 4 0 C. However, pressure vessels generally have numerous problems for use in cell preservation and transportation: (1) they cannot be readily separated from the pressurizing pump in the pressurized state; (2) they are typically heavy and expensive due the use of materials such as stainless steel; and (3) it is difficult to regulate pressurization rate with hand pumps. Therefore, we developed a transportable high-pressure system suitable for cell preservation under high-pressure conditions. This high-pressure vessel has the following characteristics: (1) it can be easily separated from the pressurizing pump due to the use of a cock-type stop valve; (2) it is small and compact, is made of PEEK and weighs less than 200 g; and (3) pressurization rate is regulated by an electric pump instead of a hand pump. Using this transportable high-pressure vessel for cell preservation, we found that astrocytes can survive for 4 days at 1.6 MPa and 4 0 C.

Probing the Gas-Phase Dynamics of Graphene Chemical Vapour Deposition using in-situ UV Absorption Spectroscopy

DEFF Research Database (Denmark)

Shivayogimath, Abhay; Mackenzie, David; Luo, Birong

2017-01-01

The processes governing multilayer nucleation in the chemical vapour deposition (CVD) of graphene are important for obtaining high-quality monolayer sheets, but remain poorly understood. Here we show that higher-order carbon species in the gas-phase play a major role in multilayer nucleation...

Electric strength of metal-ceramic brazed units of thermionic energy converters in cesium vapours

International Nuclear Information System (INIS)

Belousenko, A.P.; Vasilchenko, A.V.; Nikolaev, Y.V.

1989-01-01

The investigation of electric strength characteristics of the hollow metal-ceramic brazed units of thermionic energy converters with the insulator 1 = 10-50 mm from polycrystal aluminum oxide at the temperature T = 450-750 degrees and the cesium vapour pressure P Cs = 10 - 1 -10 3 Pa has been carried out. The experimental dependencies of the break-down voltage of the brazed units on the temperature, parameter P Cs · 1 and the value of surface electric resistance of the insulators are given as well as the empiric equations obtained with the help of experimental data for calculating the break-down voltage. A mechanism of ceramic insulator influence on electric strength characteristics of the cesium gap is investigated. A breakdown model explaining this influence is proposed

Chemical vapour deposition growth and Raman characterization of graphene layers and carbon nanotubes

Science.gov (United States)

Lai, Y.-C.; Rafailov, P. M.; Vlaikova, E.; Marinova, V.; Lin, S. H.; Yu, P.; Yu, S.-C.; Chi, G. C.; Dimitrov, D.; Sveshtarov, P.; Mehandjiev, V.; Gospodinov, M. M.

2016-02-01

Single-layer graphene films were grown by chemical vapour deposition (CVD) on Cu foil. The CVD process was complemented by plasma enhancement to grow also vertically aligned multiwalled carbon nanotubes using Ni nanoparticles as catalyst. The obtained samples were characterized by Raman spectroscopy analysis. Nature of defects in the samples and optimal growth conditions leading to achieve high quality of graphene and carbon nanotubes are discussed.

Chronic psychological effects of exposure to mercury vapour among chlorine-alkali plant workers.

Science.gov (United States)

Pranjić, N; Sinanović, O; Jakubović, R

2003-01-01

Quantitative assessment of nervous system function is essential in characterising the nature and extent of impairment in individuals experiencing symptoms following work-place mercury vapour exposure. The purpose of this study was the application of standardised tests of behavioural, psychomotor and memory function to understand the neuropsychological effects of mercury in occupationally exposed chlorine-alkali plant workers. The study comprised 45 workers at a chlorine-alkali plant with the mean age of 39.36 +/- 5.94 years, who had been exposed to daily inhalation of mercury vapour over long-term employment of 16.06 +/- 4.29 years. The cumulative mercury index was 155.32 +/- 95.02 micrograms/g creatinine, the mean of urinary mercury concentrations on the first day of the study was 119.50 +/- 157.24 micrograms/g creatinine, and the mean of urinary mercury concentrations 120 days after cessation of exposure was 21.70 +/- 26.07 micrograms/g creatinine. The analysis included tests of behavioural, psychomotor and memory function. The behavioural test battery consisted of: Environmental Worry Scale (EWS), Minnesota Modified Personal Inventory (MMPI-2), Purdue standard 25 minute test, and adapted, 10 minutes test, Bender's Visual-Motor Gestalt test (BGT), and Eysenck Personality Inventory (EPQ). The data were compared to a control group of 32 not directly exposed workers. In the mercury vapour exposed workers with relatively high level exposure to inorganic mercury vapour (TWA/TLV = 0.12 mg/m3/0.025 mg/m3) we identified somatic depression-hypochondria symptoms with higher scores for scales: hysteria (P introvert behaviour (EPQ, MMPI-2). The cognitive disturbances in mercury-exposed workers were identified as: concentration difficulty, psychomotor, perceptual and motor coordination disturbances, and brain effects. We identified fine tremor of the hands in 34 out of 45 mercury-exposed workers (BGT). The results point to a relationship between the duration of mercury

Physical-chemical and technological aspects of the preparation of think layers of the high temperature superconductors Bi-Sr-Ca-Cu-O by method of metal organic vapour phase epitaxy

International Nuclear Information System (INIS)

Stejskal, J.; Nevriva, M.; Leitner, J.

1995-01-01

The method of metal organic vapour phase epitaxy (MO VPE) was used for preparation of think layers of the high temperature superconductors Bi-Sr-Ca-Cu-O. The suitable chemical precursors (β-diketonates) on the literature data and of the own thermodynamic calculations were selected. The optimal thermodynamic data and thermodynamic stability of the prepared samples were determined

High-pressure high-temperature phase diagram of organic crystal paracetamol

Science.gov (United States)

Smith, Spencer J.; Montgomery, Jeffrey M.; Vohra, Yogesh K.

2016-01-01

High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped heating diamond anvil. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in five different experiments. Solid state phase transitions from monoclinic Form I  →  orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II  →  unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. This new data is combined with previous ambient temperature high-pressure Raman and x-ray diffraction data to create the first HPHT phase diagram of paracetamol.