WorldWideScience

Sample records for water vapor o3

  1. Water-Vapor Sorption Processes in Nanoporous MgO-Al2O3 Ceramics: the PAL Spectroscopy Study.

    Science.gov (United States)

    Klym, Halyna; Ingram, Adam; Shpotyuk, Oleh; Hadzaman, Ivan; Solntsev, Viacheslav

    2016-12-01

    The water-vapor sorption processes in nanoporous MgO-Al2O3 ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60-70 ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5-1.8-nm radii. The first o-Ps decaying process includes "pick-off" annihilation in the "bubbles" of liquid water, while the second is based on o-Ps interaction with physisorbed water molecules at the walls of the pores. In addition, the water vapor modifies structural defects located at the grain boundaries in a vicinity of pores, this process being accompanied by void fragmentation during water adsorption and agglomeration during water desorption after drying.

  2. Water-Vapor Sorption Processes in Nanoporous MgO-Al2O3 Ceramics: the PAL Spectroscopy Study

    Science.gov (United States)

    Klym, Halyna; Ingram, Adam; Shpotyuk, Oleh; Hadzaman, Ivan; Solntsev, Viacheslav

    2016-03-01

    The water-vapor sorption processes in nanoporous MgO-Al2O3 ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60-70 ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5-1.8-nm radii. The first o-Ps decaying process includes "pick-off" annihilation in the "bubbles" of liquid water, while the second is based on o-Ps interaction with physisorbed water molecules at the walls of the pores. In addition, the water vapor modifies structural defects located at the grain boundaries in a vicinity of pores, this process being accompanied by void fragmentation during water adsorption and agglomeration during water desorption after drying.

  3. Water-Vapor Sorption Processes in Nanoporous MgO-Al2O3 Ceramics: the PAL Spectroscopy Study

    OpenAIRE

    Klym, Halyna; Ingram, Adam; Shpotyuk, Oleh; Hadzaman, Ivan; Solntsev, Viacheslav

    2016-01-01

    The water-vapor sorption processes in nanoporous MgO-Al2O3 ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60?70?ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5?1.8-nm radii. The first o-Ps decaying process include...

  4. Effects of water vapor on protectiveness of Cr2O3 scale at 1073 K

    Science.gov (United States)

    Arifin, S. K.; Hamid, M.; Berahim, A. N.; Ani, M. H.

    2018-01-01

    Fe-Cr alloy is commonly being used as boiler tube’s material. It is subjected to prolonged exposure to water vapor oxidation. The ability to withstand high temperature corrosion can normally be attributed to the formation of a dense and slow growing Cr-rich-oxide scale known as chromia, Cr2O3 scale. However, oxidation may limit the alloy’s service lifetime due to decreasing of its protectiveness capability. This paper is to presents an experimental study of thermo gravimetric and Fourier transform infrared analysis of Cr2O3 at 1073 K in dry and humid environment. Samples were used from commercially available Cr2O3 powder. It was cold-pressed into pellet shape of 12 mm diameter and 3 mm thick with hydraulic press for 40 min at 48 MPa. It then sintered at 1173 K in inert gas environment for 8 h. The samples are cooled and placed in 5 mm diameter platinum pan. It is subjected to reaction in dry and wet environment at 1073 K by applying 100%-Ar and Ar-5%H2 gas. Each reaction period is 48 h utilizing Thermo Gravimetric Analyzer, TGA to quantify the mass changes. After the reaction, the samples then characterized with Fourier Transform Infrared Spectroscopy, FT-IR and Field Emission Electron Scanning Microscopy, FE-SEM. The TGA result shows mass decreasing ratio of Cr2O3 in wet (PH2O = 9.5x105Pa) and dry environment is at a factor of 1.2 while parabolic rate at 1.4. FT-IR results confirmed that water vapor significantly broaden the peaks, thus promotes the volatilization of Cr2O3 in wet sample. FESEM shows mostly packed and intact in dry while in wet sample, slightly porous particle arrangement compare to dry. It is concluded that water vapor species decreased Cr2O3 protectiveness capability.

  5. Water vapor concentration dependence and temperature dependence of Li mass loss from Li{sub 2}TiO{sub 3} with excess Li and Li{sub 4}SiO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Shimozori, Motoki [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Katayama, Kazunari, E-mail: kadzu@nucl.kyushu-u.ac.jp [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Hoshino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuch, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Ushida, Hiroki; Yamamoto, Ryotaro; Fukada, Satoshi [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan)

    2015-10-15

    Highlights: • Li mass loss from Li{sub 2.11}TiO{sub 3} increased proportionally to water vapor pressure. • Li mass loss from Li{sub 2.11}TiO{sub 3} at 600 °C was significantly smaller than expected. • Differences of Li mass loss behavior from Li{sub 2.11}TiO{sub 3} and Li{sub 4}SiO{sub 4} were shown. - Abstract: In this study, weight reduction of Li{sub 2}TiO{sub 3} with excess Li and Li{sub 4}SiO{sub 4} at elevated temperatures under hydrogen atmosphere or water vapor atmosphere was investigated. The Li mass loss for the Li{sub 2}TiO{sub 3} at 900 °C was 0.4 wt% under 1000 Pa H{sub 2} atmosphere and 1.5 wt% under 50 Pa H{sub 2}O atmosphere. The Li mass loss for the Li{sub 2}TiO{sub 3} increased proportionally to the water vapor pressure in the range from 50 to 200 Pa at 900 °C and increased with increasing temperature from 700 to 900 °C although Li mass loss at 600 °C was significantly smaller than expected. It was found that water vapor concentration dependence and temperature dependence of Li mass loss for the Li{sub 2}TiO{sub 3} and the Li{sub 4}SiO{sub 4} used in this work were quite different. Water vapor is released from the ceramic breeder materials into the purge gas due to desorption of adsorbed water and water formation reaction. The released water vapor possibly promotes Li mass loss with the formation of LiOH on the surface.

  6. Vapor pressures of nitric acid and water in the systems HNO3-H2O and HNO3-Th(NO3)4-H2O at 50oC

    International Nuclear Information System (INIS)

    Lemire, R.J.; Brown, C.P.; Campbell, A.B.

    1985-01-01

    The equilibrium compositions of the vapor above nitric acid-water, thorium nitrate-water, and nitric acid-thorium nitrate-water mixtures at 50 o C have been studied as a function of solution concentration by using a transpiration technique. Nitric acid concentrations were varied from 0 to 20 m and thorium nitrate concentrations from 0 to 2.5 m. Our data for the nitric acid-water system have been combined with literature data to obtain parameters for Scatchard's ion-component model, and these parameters provide a satisfactory description of the system at 50 o C over a wide concentration range. The enhancement, at 50 o C, of the nitric acid vapor pressure by added thorium nitrate was found to be less than that previously determined at 25 o C. The data for the nitric acid-thorium nitrate-water system at 50 o C were fitted to a single multiparameter function. (author)

  7. Growth behavior of LiMn2O4 particles formed by solid-state reactions in air and water vapor

    International Nuclear Information System (INIS)

    Kozawa, Takahiro; Yanagisawa, Kazumichi; Murakami, Takeshi; Naito, Makio

    2016-01-01

    Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn 2 O 4 particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn 2 O 4 particles in air and water vapor atmospheres as model reactions; LiMn 2 O 4 is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO 3 precursor impregnated with LiOH, LiMn 2 O 4 spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled. - Graphical abstract: This study has demonstrated a new strategy towards achieving morphology control without the use of additives during conventional solid-state reactions by exploiting water vapor-induced particle growth. - Highlights: • A new strategy to control the morphology of LiMn 2 O 4 particles is proposed. • Water vapor-induced particle growth is exploited in solid-state reactions. • The microstructural evolution of LiMn 2 O 4 particles is investigated. • The shape, size and microstructure can be controlled by solid-state reactions.

  8. Experiment HFR-B1: A preliminary analysis of the water-vapor injection experiments in capsule 3

    International Nuclear Information System (INIS)

    Myers, B.F.

    1993-01-01

    A preliminary analysis of the response of uranium oxycarbide (UCO) fuel to water vapor addition in capsule 3 of experiment HFR-B1 (HFR-B1/3) has been conducted. The analysis provides an early indication of the behavior of fission gas release under a wider range of water-vapor pressures and of temperatures than heretofore studied. A preliminary analysis of selected aspects of the water-vapor injection tests in capsule 3 of experiment HFR-B1 is presented. The release of fission gas stored in bubbles and the diffusive release of fission-gas atoms are distinguished. The dependence of the release of stored fission gas ( 85m Kr) on water-vapor pressure, P(H 2 O), and temperature were established taking into account the contributing mechanisms of gaseous release, the effect of graphite hydrolysis, and the requirement of consistency with experiment HRB-17 in which similar water-vapor injection tests were conducted. The dependence on P(H 2 O) becomes weaker as temperatures increase above 770 degree C; the activation energy for release of stored-fission gas is 393 kJ/mol. Isorelease curves for the pressure-temperature plane were deduced from a derived functional relation. The stored-fission gas releases as a function of P(H 2 O) at a common temperature for experiments HFR-B1 and HRB-17 differ by a factor of 4; this discrepancy could be attributed to the differences in fission-rate density and neutron flux between the two experiments. Diffusive release of fission gas occurred during and after the release of stored gas. The ratio of diffusive release during water-vapor injection to that prior to injection varied in contrast to the results from HRB-17. The variation was attributed to the practice of injecting water vapor into HFR-B1 before sintering of the fuel, hydrolyzed in the previous test, was completed. The derived activation energy for diffusive release is 23.6 kJ/mol

  9. Experiment HFR-B1: A preliminary analysis of the water-vapor injection experiments in capsule 3

    Energy Technology Data Exchange (ETDEWEB)

    Myers, B.F.

    1993-08-01

    A preliminary analysis of the response of uranium oxycarbide (UCO) fuel to water vapor addition in capsule 3 of experiment HFR-B1 (HFR-B1/3) has been conducted. The analysis provides an early indication of the behavior of fission gas release under a wider range of water-vapor pressures and of temperatures than heretofore studied. A preliminary analysis of selected aspects of the water-vapor injection tests in capsule 3 of experiment HFR-B1 is presented. The release of fission gas stored in bubbles and the diffusive release of fission-gas atoms are distinguished. The dependence of the release of stored fission gas ({sup 85m}Kr) on water-vapor pressure, P(H{sub 2}O), and temperature were established taking into account the contributing mechanisms of gaseous release, the effect of graphite hydrolysis, and the requirement of consistency with experiment HRB-17 in which similar water-vapor injection tests were conducted. The dependence on P(H{sub 2}O) becomes weaker as temperatures increase above 770{degree}C; the activation energy for release of stored-fission gas is 393 kJ/mol. Isorelease curves for the pressure-temperature plane were deduced from a derived functional relation. The stored-fission gas releases as a function of P(H{sub 2}O) at a common temperature for experiments HFR-B1 and HRB-17 differ by a factor of 4; this discrepancy could be attributed to the differences in fission-rate density and neutron flux between the two experiments. Diffusive release of fission gas occurred during and after the release of stored gas. The ratio of diffusive release during water-vapor injection to that prior to injection varied in contrast to the results from HRB-17. The variation was attributed to the practice of injecting water vapor into HFR-B1 before sintering of the fuel, hydrolyzed in the previous test, was completed. The derived activation energy for diffusive release is 23.6 kJ/mol.

  10. SPADE H2O measurements and the seasonal cycle of statospheric water vapor

    Science.gov (United States)

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

    1994-01-01

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

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

    Science.gov (United States)

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

    1997-01-01

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

  12. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan

    2017-09-13

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  13. Polybenzimidazole-based mixed membranes with exceptional high water vapor permeability and selectivity

    KAUST Repository

    Akhtar, Faheem Hassan; Kumar, Mahendra; Villalobos, Luis Francisco; Shevate, Rahul; Vovusha, Hakkim; Schwingenschlö gl, Udo; Peinemann, Klaus-Viktor

    2017-01-01

    Polybenzimidazole (PBI), a thermal and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. Incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N2 selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO2 nanotubes yielded a water vapor permeability of 6.8×104 Barrer and a H2O/N2 selectivity of 3.9×106. The most permeable membrane with 1 wt% loading of carboxylated TiO2 nanoparticles had a 7.1×104 Barrer water vapor permeability and a H2O/N2 selectivity of 3.1×106. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.

  14. High Temperature Corrosion of Silicon Carbide and Silicon Nitride in Water Vapor

    Science.gov (United States)

    Opila, E. J.; Robinson, Raymond C.; Cuy, Michael D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Silicon carbide (SiC) and silicon nitride (Si3N4) are proposed for applications in high temperature combustion environments containing water vapor. Both SiC and Si3N4 react with water vapor to form a silica (SiO2) scale. It is therefore important to understand the durability of SiC, Si3N4 and SiO2 in water vapor. Thermogravimetric analyses, furnace exposures and burner rig results were obtained for these materials in water vapor at temperatures between 1100 and 1450 C and water vapor partial pressures ranging from 0.1 to 3.1 atm. First, the oxidation of SiC and Si3N4 in water vapor is considered. The parabolic kinetic rate law, rate dependence on water vapor partial pressure, and oxidation mechanism are discussed. Second, the volatilization of silica to form Si(OH)4(g) is examined. Mass spectrometric results, the linear kinetic rate law and a volatilization model based on diffusion through a gas boundary layer are discussed. Finally, the combined oxidation and volatilization reactions, which occur when SiC or Si3N4 are exposed in a water vapor-containing environment, are presented. Both experimental evidence and a model for the paralinear kinetic rate law are shown for these simultaneous oxidation and volatilization reactions.

  15. Growth behavior of LiMn{sub 2}O{sub 4} particles formed by solid-state reactions in air and water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Kozawa, Takahiro, E-mail: t-kozawa@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11–1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yanagisawa, Kazumichi [Research Laboratory of Hydrothermal Chemistry, Faculty of Science, Kochi University, 2–5-1 Akebono-cho, Kochi 780-8520 (Japan); Murakami, Takeshi; Naito, Makio [Joining and Welding Research Institute, Osaka University, 11–1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2016-11-15

    Morphology control of particles formed during conventional solid-state reactions without any additives is a challenging task. Here, we propose a new strategy to control the morphology of LiMn{sub 2}O{sub 4} particles based on water vapor-induced growth of particles during solid-state reactions. We have investigated the synthesis and microstructural evolution of LiMn{sub 2}O{sub 4} particles in air and water vapor atmospheres as model reactions; LiMn{sub 2}O{sub 4} is used as a low-cost cathode material for lithium-ion batteries. By using spherical MnCO{sub 3} precursor impregnated with LiOH, LiMn{sub 2}O{sub 4} spheres with a hollow structure were obtained in air, while angulated particles with micrometer sizes were formed in water vapor. The pore structure of the particles synthesized in water vapor was found to be affected at temperatures below 700 °C. We also show that the solid-state reaction in water vapor is a simple and valuable method for the large-scale production of particles, where the shape, size, and microstructure can be controlled. - Graphical abstract: This study has demonstrated a new strategy towards achieving morphology control without the use of additives during conventional solid-state reactions by exploiting water vapor-induced particle growth. - Highlights: • A new strategy to control the morphology of LiMn{sub 2}O{sub 4} particles is proposed. • Water vapor-induced particle growth is exploited in solid-state reactions. • The microstructural evolution of LiMn{sub 2}O{sub 4} particles is investigated. • The shape, size and microstructure can be controlled by solid-state reactions.

  16. Vapor-liquid equilibrium of the Mg(NO3)2-HNO3-H2O system

    International Nuclear Information System (INIS)

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

    1983-06-01

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

  17. Equilibrium water vapor pressures over polyvanadates M2V12O30.7·nH2O

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  18. Study of kinetics of reaction of lithium deuteride powder with O2, CO2 and water vapor

    International Nuclear Information System (INIS)

    Li Gan; Lu Guangda; Jing Wenyong; Qin Cheng

    2004-01-01

    The kinetics of reaction of lithium deuteride powder with O 2 , CO 2 and water vapor is studied. The experimental results show that lithium deuteride reacts with O 2 and CO 2 at very small reaction rate but with water vapor at comparatively larger rate at room temperature (≅28 degree C). The reaction process with water vapor could be described using the unreacted shrinking core model. The second-order kinetics is appropriate for the chemical reaction on the surface of lithium deuteride and reaction rate constant is 0.281 kPa -1 ·min -1

  19. Li vaporization property of two-phase material of Li{sub 2}TiO{sub 3} and Li{sub 2}SiO{sub 3} for tritium breeder

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Seiya [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Masuko, Yuki; Kato, Hirokazu; Yuyama, Hayato; Sakai, Yutaro [Department of Prime Mover Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Niwa, Eiki; Hashimoto, Takuya [Department of Physics, College of Humanities and Sciences, Nihon University, 3-8-1 Sakurajousui, Setagaya-ku, Tokyo 156-8550 (Japan); Mukai, Keisuke [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-8656 (Japan); Hosino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuch, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Sasaki, Kazuya, E-mail: k_sasaki@tokai-u.jp [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Department of Prime Mover Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Course of Mechanical Engineering and Aeronautics and Astronautics, Graduate School of Science and Technology, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

    2015-10-15

    Highlights: • We synthesized two phase materials based on Li{sub 2}SiO{sub 3} and Li{sub 2}TiO{sub 3}. • We investigated the Li vaporization property of the two-phase materials. • Li vaporization occurs significantly from only Li{sub 2}SiO{sub 3} grains in the vicinity of the surface of the pellets. • The Li vaporization is remarkable only for an early short time for the vaporization from Li{sub 2}SiO{sub 3} grains at the vicinity of the surface. • The second stable phase added functions effectively for inhibition of the Li vaporization. - Abstract: Li vaporization property of two-phase materials of Li{sub 2}TiO{sub 3} and Li{sub 2}SiO{sub 3} in a working condition for the solid tritium breeder used in the demonstration power plant of fusion reactor was investigated, and the suppression mechanism of the vaporization was considered. The Li vaporization rate from the specimen pellet was measured by gravimetric method, and the change of Li concentration distribution in the pellet was analyzed by time-of-flight secondary ion mass spectrometer. Li was vaporized only from the Li{sub 2}SiO{sub 3} at the vicinity of the surface of the pellet. The remarkable vaporization of Li arose only in an early short time. The inhibition of the vaporization from the Li{sub 2}SiO{sub 3} was successful by adding the small amount of the stable secondary phase of Li{sub 2}TiO{sub 3}.

  20. Water Vapor Permeation of Metal Oxide/Polymer Coated Plastic Films

    Science.gov (United States)

    Numata, Yukihiro; Oya, Toshiyuki; Kuwahara, Mitsuru; Ito, Katsuya

    Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how to control interfacial properties between each layer and film for good barrier performance. Several kinds of polymer coated materials were prepared for changing surface free energy of the films before and after depositing the ceramic layer. The ceramic layer, which is composed of mixed material of SiO2 and Al2O3, was adopted under the same conditions. The following results were obtained; 1) Water vapor permeation is not related to the surface energy of polymer coated films, 2) After depositing the ceramic layer, however, a strong correlation is observed between the water vapor permeation and surface free energy. 3) The phenomenon is considered that the polarity of the polymer layers plays a key role in changing the structure of ceramic coated layers.

  1. The Vaporization of B2O3(l) to B2O3(g) and B2O2(g)

    Science.gov (United States)

    Jacobson, Nathan S.; Myers, Dwight L.

    2011-01-01

    The vaporization of B2O3 in a reducing environment leads to formation of both B2O3(g) and B2O2(g). While formation of B2O3(g) is well understood, many questions about the formation of B2O2(g) remain. Previous studies using B(s) + B2O3(l) have led to inconsistent thermodynamic data. In this study, it was found that after heating, B(s) and B2O3(l) appear to separate and variations in contact area likely led to the inconsistent vapor pressures of B2O2(g). To circumvent this problem, an activity of boron is fixed with a two-phase mixture of FeB and Fe2B. Both second and third law enthalpies of formation were measured for B2O2(g) and B2O3(g). From these the enthalpies of formation at 298.15 K are calculated to be -479.9 +/- 41.5 kJ/mol for B2O2(g) and -833.4 +/- 13.1 kJ/mol for B2O3(g). Ab initio calculations to determine the enthalpies of formation of B2O2(g) and B2O3(g) were conducted using the W1BD composite method and show good agreement with the experimental values.

  2. Major Upgrades to the AIRS Version-6 Water Vapor Profile Methodology

    Science.gov (United States)

    Susskind, Joel; Blaisdell, John; Iredell, Lena

    2015-01-01

    This research is a continuation of part of what was shown at the last AIRS Science Team Meeting and the AIRS 2015 NetMeeting. AIRS Version 6 was finalized in late 2012 and is now operational. Version 6 contained many significant improvements in retrieval methodology compared to Version 5. Version 6 retrieval methodology used for the water vapor profile q(p) and ozone profile O3(p) retrievals is basically unchanged from Version 5, or even from Version 4. Subsequent research has made significant improvements in both water vapor and O3 profiles compared to Version 6.

  3. Dual effects of water vapor on ceria-supported gold clusters.

    Science.gov (United States)

    Li, Zhimin; Li, Weili; Abroshan, Hadi; Ge, Qingjie; Li, Gao; Jin, Rongchao

    2018-04-05

    Atomically precise nanocatalysts are currently being intensely pursued in catalysis research. Such nanocatalysts can serve as model catalysts for gaining fundamental insights into catalytic processes. In this work we report a discovery that water vapor provokes the mild removal of surface long-chain ligands on 25-atom Au25(SC12H25)18 nanoclusters in a controlled manner. Using the resultant Au25(SC12H25)18-x/CeO2 catalyst and CO oxidation as a probe reaction, we found that the catalytic activity of cluster/CeO2 is enhanced from nearly zero conversion of CO (in the absence of water) to 96.2% (in the presence of 2.3 vol% H2O) at the same temperature (100 °C). The cluster catalysts exhibit high stability during the CO oxidation process under moisture conditions (up to 20 vol% water vapor). Water vapor plays a dual role in gold cluster-catalyzed CO oxidation. FT-IR and XPS analyses in combination with density functional theory (DFT) simulations suggest that the "-SC12H25" ligands are easier to be removed under a water vapor atmosphere, thus generating highly active sites. Moreover, the O22- peroxide species constitutes the active oxygen species in CO oxidation, evidenced by Raman spectroscopy analysis and isotope experiments on the CeO2 and cluster/CeO2. The results also indicate the perimeter sites of the interface of Au25(SC12H25)18-x/CeO2 to be active sites for catalytic CO oxidation. The controlled exposure of active sites under mild conditions is of critical importance for the utilization of clusters in catalysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mun, S Y; Lee, H

    1999-12-01

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

  5. Low-Temperature Process for Atomic Layer Chemical Vapor Deposition of an Al2O3 Passivation Layer for Organic Photovoltaic Cells.

    Science.gov (United States)

    Kim, Hoonbae; Lee, Jihye; Sohn, Sunyoung; Jung, Donggeun

    2016-05-01

    Flexible organic photovoltaic (OPV) cells have drawn extensive attention due to their light weight, cost efficiency, portability, and so on. However, OPV cells degrade quickly due to organic damage by water vapor or oxygen penetration when the devices are driven in the atmosphere without a passivation layer. In order to prevent damage due to water vapor or oxygen permeation into the devices, passivation layers have been introduced through methods such as sputtering, plasma enhanced chemical vapor deposition, and atomic layer chemical vapor deposition (ALCVD). In this work, the structural and chemical properties of Al2O3 films, deposited via ALCVD at relatively low temperatures of 109 degrees C, 200 degrees C, and 300 degrees C, are analyzed. In our experiment, trimethylaluminum (TMA) and H2O were used as precursors for Al2O3 film deposition via ALCVD. All of the Al2O3 films showed very smooth, featureless surfaces without notable defects. However, we found that the plastic flexible substrate of an OPV device passivated with 300 degrees C deposition temperature was partially bended and melted, indicating that passivation layers for OPV cells on plastic flexible substrates need to be formed at temperatures lower than 300 degrees C. The OPV cells on plastic flexible substrates were passivated by the Al2O3 film deposited at the temperature of 109 degrees C. Thereafter, the photovoltaic properties of passivated OPV cells were investigated as a function of exposure time under the atmosphere.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  8. Nonlinear response of tropical lower-stratospheric temperature and water vapor to ENSO

    Science.gov (United States)

    Garfinkel, Chaim I.; Gordon, Amit; Oman, Luke D.; Li, Feng; Davis, Sean; Pawson, Steven

    2018-04-01

    A series of simulations using the NASA Goddard Earth Observing System Chemistry-Climate Model are analyzed in order to aid in the interpretation of observed interannual and sub-decadal variability in the tropical lower stratosphere over the past 35 years. The impact of El Niño-Southern Oscillation on temperature and water vapor in this region is nonlinear in boreal spring. While moderate El Niño events lead to cooling in this region, strong El Niño events lead to warming, even as the response of the large-scale Brewer-Dobson circulation appears to scale nearly linearly with El Niño. This nonlinearity is shown to arise from the response in the Indo-West Pacific to El Niño: strong El Niño events lead to tropospheric warming extending into the tropical tropopause layer and up to the cold point in this region, where it allows for more water vapor to enter the stratosphere. The net effect is that both strong La Niña and strong El Niño events lead to enhanced entry water vapor and stratospheric moistening in boreal spring and early summer. These results lead to the following interpretation of the contribution of sea surface temperatures to the decline in water vapor in the early 2000s: the very strong El Niño event in 1997/1998, followed by more than 2 consecutive years of La Niña, led to enhanced lower-stratospheric water vapor. As this period ended in early 2001, entry water vapor concentrations declined. This effect accounts for approximately one-quarter of the observed drop.

  9. Nonlinear response of tropical lower-stratospheric temperature and water vapor to ENSO

    Directory of Open Access Journals (Sweden)

    C. I. Garfinkel

    2018-04-01

    Full Text Available A series of simulations using the NASA Goddard Earth Observing System Chemistry–Climate Model are analyzed in order to aid in the interpretation of observed interannual and sub-decadal variability in the tropical lower stratosphere over the past 35 years. The impact of El Niño–Southern Oscillation on temperature and water vapor in this region is nonlinear in boreal spring. While moderate El Niño events lead to cooling in this region, strong El Niño events lead to warming, even as the response of the large-scale Brewer–Dobson circulation appears to scale nearly linearly with El Niño. This nonlinearity is shown to arise from the response in the Indo-West Pacific to El Niño: strong El Niño events lead to tropospheric warming extending into the tropical tropopause layer and up to the cold point in this region, where it allows for more water vapor to enter the stratosphere. The net effect is that both strong La Niña and strong El Niño events lead to enhanced entry water vapor and stratospheric moistening in boreal spring and early summer. These results lead to the following interpretation of the contribution of sea surface temperatures to the decline in water vapor in the early 2000s: the very strong El Niño event in 1997/1998, followed by more than 2 consecutive years of La Niña, led to enhanced lower-stratospheric water vapor. As this period ended in early 2001, entry water vapor concentrations declined. This effect accounts for approximately one-quarter of the observed drop.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  11. Water vapor emission from H II regions and infrared stars

    International Nuclear Information System (INIS)

    Cato, B.T.; Ronnang, B.O.; Rydbeck, O.E.H.; Lewin, P.T.; Yngvesson, K.S.; Cardiasmenos, A.G.; Shanley, J.F.

    1976-01-01

    The spatial structure of water vapor microwave line emission has been investigated with moderate angular resolution in several well-known H II regions. New H 2 O sources have been with infrared (1R) sources. One of these sources, IRC: 20411, has been investigated at optical wavelengths. It is found to be of spectral class M3-M5 and by indirect evidence the luminosity class is preliminarily determined to Ib. The distance is estimated to be approx.2 kpc, and the star must be in front of the dust complex which obscures W28 A2. In NGC 7538 new high-velocity features have been discovered. Two new weak water vapor masers, G30.1: 0.7 and G32.8: 0.3, have been detected in a search among eight class II OH/IR sources. H 2 O emission coinciding with the low-velocity OH features of VY Canis Majoris has also been detected. A search for local thermodynamic equilibrium (LTE) water-vapor line emission in molecular clouds associated with H II regions is also reported. No line was detected with the utilized sensitivity. The physical implications of this are discussed and an upper limit of the H 2 O column density has been estimated. Gaussian analysis of the strong, narrow feature in the spectrum of ON 1 indicates a possible presence of two hyperfine components, viz., F→F'=7→6 and 6→5

  12. Epitaxial Pb(Mg1/3Nb2/3)O3 thin films synthesized by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Bai, G. R.; Streiffer, S. K.; Baumann, P. K.; Auciello, O.; Ghosh, K.; Stemmer, S.; Munkholm, A.; Thompson, Carol; Rao, R. A.; Eom, C. B.

    2000-01-01

    Metal-organic chemical vapor deposition was used to prepare Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) thin films on (001) SrTiO 3 and SrRuO 3 /SrTiO 3 substrates, using solid Mg β-diketonate as the Mg precursor. Parameters including the precursor ratio in the vapor phase, growth temperature, growth rate, and reaction pressure in the reactor chamber were varied in order to determine suitable growth conditions for producing phase-pure, epitaxial PMN films. A cube-on-cube orientation relationship between the thin film and the SrTiO 3 substrate was found, with a (001) rocking curve width of 0.1 degree sign , and in-plane rocking-curve width of 0.8 degree sign . The root-mean-square surface roughness of a 200-nm-thick film on SrTiO 3 was 2 to 3 nm as measured by scanning probe microscopy. The zero-bias dielectric constant and loss measured at room temperature and 10 kHz for a 200-nm-thick film on SrRuO 3 /SrTiO 3 were approximately 1100 and 2%, respectively. The remnant polarization for this film was 16 μC/cm 2 . (c) 2000 American Institute of Physics

  13. HERSCHEL /HIFI OBSERVATIONS OF IRC+10216: WATER VAPOR IN THE INNER ENVELOPE OF A CARBON-RICH ASYMPTOTIC GIANT BRANCH STAR

    International Nuclear Information System (INIS)

    Neufeld, David A.; Gonzalez-Alfonso, Eduardo; Melnick, Gary J.; Szczerba, Ryszard; Schmidt, Miroslaw; Decin, Leen; De Koter, Alex; Schoeier, Fredrik; Cernicharo, Jose

    2011-01-01

    We report the results of observations of 10 rotational transitions of water vapor toward the carbon-rich asymptotic giant branch (AGB) star IRC+10216 (CW Leonis), carried out with Herschel's HIFI instrument. Each transition was securely detected by means of observations using the dual beam switch mode of HIFI. The measured line ratios imply that water vapor is present in the inner outflow at small distances (≤few x 10 14 cm) from the star, confirming recent results reported by Decin et al. from observations with Herschel's PACS and SPIRE instruments. This finding definitively rules out the hypothesis that the observed water results from the vaporization of small icy objects in circular orbits. The origin of water within the dense C-rich envelope of IRC+10216 remains poorly understood. We derive upper limits on the H 17 2 O/H 16 2 O and H 18 2 O/H 16 2 O isotopic abundance ratios of ∼5 x 10 -3 (3σ), providing additional constraints on models for the origin of the water vapor in IRC+10216.

  14. High-temperature mass spectrometric study of the vaporization processes and thermodynamic properties of melts in the PbO-B2O3-SiO2 system.

    Science.gov (United States)

    Stolyarova, V L; Lopatin, S I; Shilov, A L; Shugurov, S M

    2013-07-15

    The unique properties of the PbO-B2O3-SiO2 system, especially its extensive range of glass-forming compositions, make it valuable for various practical applications. The thermodynamic properties and vaporization of PbO-B2O3-SiO2 melts are not well established so far and the data obtained on these will be useful for optimization of technology and thermodynamic modeling of glasses. High-temperature Knudsen effusion mass spectrometry was used to study vaporization processes and to determine the partial pressures of components of the PbO-B2O3-SiO2 melts. Measurements were performed with a MS-1301 mass spectrometer. Vaporization was carried out using two quartz effusion cells containing the sample under study and pure PbO (reference substance). Ions were produced by electron ionization at an energy of 25 eV. To facilitate interpretation of the mass spectra, the appearance energies of ions were also measured. Pb, PbO and O2 were found to be the main vapor species over the samples studied at 1100 K. The PbO activities as a function of the composition of the system were derived from the measured PbO partial pressures. The B2O3 and SiO2 activities, the Gibbs energy of formation, the excess Gibbs energy of formation and mass losses in the samples studied were calculated. Partial pressures of the vapor species over PbO-B2O3-SiO2 melts were measured at 1100 K in the wide range of compositions using the Knudsen mass spectrometric method. The data enabled the PbO, B2O3, and SiO2 activities in these melts to be derived and provided evidence of their negative deviations from ideal behavior. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Vertical profiles of Mars 1.27 μm O2 dayglow from MRO CRISM limb spectra: Seasonal/global behaviors, comparisons to LMDGCM simulations, and a global definition for Mars water vapor profiles

    Science.gov (United States)

    Todd Clancy, R.; Smith, Michael D.; Lefèvre, Franck; McConnochie, Timothy H.; Sandor, Brad J.; Wolff, Michael J.; Lee, Steven W.; Murchie, Scott L.; Toigo, Anthony D.; Nair, Hari; Navarro, Thomas

    2017-09-01

    Since July of 2009, The Compact Reconnaissance Imaging Spectral Mapper (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) has periodically obtained pole-to-pole observations (i.e., full MRO orbits) of limb scanned visible/near IR spectra (λ = 0.4 - 4.0 μ m, △λ ∼ 10 nm- Murchie et al., 2007). These CRISM limb observations support the first seasonally and spatially extensive set of Mars 1.27 μm O2(1△g) dayglow profile retrievals (∼ 1100) over ≥ 8-80 km altitudes. Their comparison to Laboratoire de Météorologie Dynamique (LMD) global climate model (GCM) simulated O2(1△g) volume emission rate (VER) profiles, as a function of altitude, latitude, and season (solar longitude, Ls), supports several key conclusions regarding Mars atmospheric water vapor (which is derived from O2(1△g) emission rates), Mars O3, and the collisional de-excitation of O2(1△g) in the Mars CO2 atmosphere. Current (Navarro et al., 2014) LMDGCM simulations of Mars atmospheric water vapor fall 2-3 times below CRISM derived water vapor abundances at 20-40 km altitudes over low-to-mid latitudes in northern spring (Ls = 30-60°), and northern mid-to-high latitudes over northern summer (Ls = 60-140°). In contrast, LMDGCM simulated water vapor is 2-5 times greater than CRISM derived values at all latitudes and seasons above 40 km, within the aphelion cloud belt (ACB), and over high-southern to mid-southern latitudes in southern summer (Ls = 190-340°) at 15-35 km altitudes. Overall, the solstitial summer-to-winter hemisphere gradients in water vapor are reversed between the LMDGCM modeled versus the CRISM derived water vapor abundances above 10-30 km altitudes. LMDGCM-CRISM differences in water vapor profiles correlate with LMDGCM-CRISM differences in cloud mixing profiles; and likely reflect limitations in simulating cloud microphysics and radiative forcing, both of which restrict meridional transport of water from summer-to-winter hemispheres on Mars (Clancy et al., 1996

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

    International Nuclear Information System (INIS)

    Pequenin, Ana; Asensi, Juan Carlos; Gomis, Vicente

    2011-01-01

    Highlights: → Water-ethanol-cyclohexane-heptane and water-cyclohexane-heptane isobaric VLLE. → Isobaric experimental data were determined at 101.3 kPa. → A dynamic recirculating still with an ultrasonic homogenizer was used. → The quaternary system does not present quaternary azeotropes. - Abstract: Experimental isobaric (vapor + liquid + liquid) and (vapor + liquid) equilibrium data for the ternary system {water (1) + cyclohexane (2) + heptane (3)} and the quaternary system {water (1) + ethanol (2) + cyclohexane (3) + heptane (4)} were measured at 101.3 kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by Wisniak for testing the thermodynamic consistency of isobaric measurements was used to test the equilibrium data.

  17. Water Adsorption on a-Fe2O3(0001) at Near Ambient Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Susumu

    2011-08-19

    We have investigated hydroxylation and water adsorption on {alpha}-Fe{sub 2}O{sub 3}(0001) at water vapor pressures up to 2 Torr and temperatures ranging from 277 to 647 K (relative humidity (RH) {le} 34%) using ambient-pressure X-ray photoelectron spectroscopy (XPS). Hydroxylation occurs at the very low RH of 1 x 10{sup -7} % and precedes the adsorption of molecular water. With increasing RH, the OH coverage increases up to one monolayer (ML) without any distinct threshold pressure. Depth profiling measurements showed that hydroxylation occurs only at the topmost surface under our experimental conditions. The onset of molecular water adsorption varies from {approx}2 x 10{sup -5} to {approx} 4 x 10{sup -2} % RH depending on sample temperature and water vapor pressure. The coverage of water reaches 1 ML at {approx}15% RH and increases to 1.5 ML at 34% RH.

  18. An opacity-sampled treatment of water vapor

    Science.gov (United States)

    Alexander, David R.; Augason, Gordon C.; Johnson, Hollis R.

    1989-01-01

    Although the bands of H2O are strong in the spectra of cool stars and calculations have repeatedly demonstrated their significance as opacity sources, only approximate opacities are currently available, due both to the difficulty of accounting for the millions of lines involved and to the inadequacy of laboratory and theoretical data. To overcome these obstacles, a new treatment is presented, based upon a statistical representation of the water vapor spectrum derived from available laboratory data. This statistical spectrum of water vapor employs an exponential distribution of line strengths and random positions of lines whose overall properties are forced to reproduce the mean opacities observed in the laboratory. The resultant data set is then treated by the opacity-sampling method exactly as are all other lines, both molecular and atomic. Significant differences are found between the results of this improved treatment and the results obtained with previous treatments of water-vapor opacity.

  19. Analyses on Water Vapor Resource in Chengdu City

    Science.gov (United States)

    Liu, B.; Xiao, T.; Wang, C.; Chen, D.

    2017-12-01

    Chengdu is located in the Sichuan basin, and it is the most famous inland city in China. With suitable temperatures and rainfall, Chengdu is the most livable cities in China. With the development of urban economy and society, the population has now risen to 16 million, and it will up to 22 million in 2030. This will cause the city water resources demand, and the carrying capacity of water resources become more and more serious. In order to improve the contradiction between urban waterlogging and water shortage, sponge city planning was proposed by Chengdu government, and this is of great practical significance for promoting the healthy development of the city. Base on the reanalysis data from NCEP during 2007-2016, the characters of Water Vapor Resources was analyzed, and the main contents of this research are summarized as follows: The water vapor resource in Chengdu plain is more than that in Southeast China and less in Northwest China. The annual average water vapor resource is approximately 160 mm -320 mm, and the water vapor resource in summer can reach 3 times in winter. But the annual average precipitation in Chengdu is about 800 mm -1200 mm and it is far greater than the water vapor resource, this is because of the transport of water vapor. Using the formula of water vapor flux, the water vapor in Chengdu is comes from the west and the south, and the value is around 50kg/(ms). Base on the calculation of boundary vapor budget, the water vapor transport under 500hPa accounted for 97% of the total. Consider the water vapor transport, transformation and urban humidification effect, the Water Vapor Resource in Chengdu is 2500mm, and it can be used by artificial precipitation enhancement. Therefore, coordinated development of weather modification and sponge city construction, the shortage of water resources in Chengdu plain can be solved. Key words: Chengdu; Sponge city; Water vapor resource; Precipitation; Artificial precipitation enhancement Acknowledgements

  20. Water vapor absorption of carbon dioxide laser radiation

    Science.gov (United States)

    Shumate, M. S.; Menzies, R. T.; Margolis, J. S.; Rosengren, L.-G.

    1976-01-01

    An optoacoustic detector or spectrophone has been used to perform detailed measurements of the absorptivity of mixtures of water vapor in air. A (C-12) (O-16)2 laser was used as the source, and measurements were made at forty-nine different wavelengths from 9.2 to 10.7 microns. The details of the optoacoustic detector and its calibration are presented, along with a discussion of its performance characteristics. The results of the measurements of water vapor absorption show that the continuum absorption in the wavelength range covered is 5-10% lower than previous measurements.

  1. Modeling UTLS water vapor: Transport/Chemistry interactions

    International Nuclear Information System (INIS)

    Gulstad, Line

    2005-01-01

    This thesis was initially meant to be a study on the impact on chemistry and climate from UTLS water vapor. However, the complexity of the UTLS water vapor and its recent changes turned out to be a challenge by it self. In the light of this, the overall motivation for the thesis became to study the processes controlling UTLS water vapor and its changes. Water vapor is the most important greenhouse gas, involved in important climate feedback loops. Thus, a good understanding of the chemical and dynamical behavior of water vapor in the atmosphere is crucial for understanding the climate changes in the last century. Additionally, parts of the work was motivated by the development of a coupled climate chemistry model based on the CAM3 model coupled with the Chemical Transport Model Oslo CTM2. The future work will be concentrated on the UTLS water vapor impact on chemistry and climate. We are currently studying long term trends in UTLS water vapor, focusing on identification of the different processes involved in the determination of such trends. The study is based on natural as well as anthropogenic climate forcings. The ongoing work on the development of a coupled climate chemistry model will continue within our group, in collaboration with Prof. Wei-Chyung Wang at the State University of New York, Albany. Valuable contacts with observational groups are established during the work on this thesis. These collaborations will be continued focusing on continuous model validation, as well as identification of trends and new features in UTLS water vapor, and other tracers in this region. (Author)

  2. A Microdrop Generator for the Calibration of a Water Vapor Isotope Ratio Spectrometer

    NARCIS (Netherlands)

    Iannone, Rosario Q.; Romanini, Daniele; Kassi, Samir; Meijer, Harro A. J.; Kerstel, Erik R. Th.

    A microdrop generator is described that produces water vapor with a known isotopic composition and volume mixing ratio for the calibration of a near-infrared diode laser water isotope ratio spectrometer. The spectrometer is designed to measure in situ the water vapor deuterium and oxygen ((17)O and

  3. CO2 AND O3 ALTER PHOTOSYNTHESIS AND WATER VAPOR EXCHANGE FOR PINUS PONDEROSA NEEDLES

    Science.gov (United States)

    1. Effects of CO2 and O3 were determined for a key component of ecosystem carbon and water cycling: needle gas exchange (photosynthesis, conductance, transpiration and water use efficiency). The measurements were made on Pinus ponderosa seedlings grown in outdoor, sunlit, mesoc...

  4. Vaporization Rate Analysis of Primary Cooling Water from Reactor PUSPATI TRIGA (RTP) Tank

    International Nuclear Information System (INIS)

    Tonny Anak Lanyau; Mohd Fazli Zakaria; Yahya Ismail

    2011-01-01

    Primary cooling system consists of pumps, heat exchangers, probes, a nitrogen-16 diffuser and associated valves is connected to the reactor TRIGA PUSPATI (RTP) tank by aluminium pipes. Both the primary cooling system and the reactor tank is filled with demineralized light water (H 2 O), which serves as a coolant, moderator as well as shielding. During reactor operation, vaporization in the reactor tank will reduce the primary water and contribute to the formation of vapor in the reactor hall. The vaporization may influence the function of the water subsequently may affect the safety of the reactor operation. It is essential to know the vaporization rate of the primary water to ensure its functionality. This paper will present the vaporization rate of the primary cooling water from the reactor tank and the influence of temperature of the water in the reactor tank to the vaporization rate. (author)

  5. Preparation of hydrogenated-TiO2/Ti double layered thin films by water vapor plasma treatment

    International Nuclear Information System (INIS)

    Pranevicius, L.L.; Milcius, D.; Tuckute, S.; Gedvilas, K.

    2012-01-01

    Highlights: ► We investigated reaction of water plasma with nanocrystalline TiO 2 films. ► Simultaneous oxidation and hydrogenation of Ti was observed during plasma treatment. ► Water plasma treatment forms hydrogenated nanocrystalline TiO 2 in the shallow surface. - Abstract: We have investigated the structural and compositional variations in 200–500 nm thick Ti films deposited by magnetron sputter-deposition technique and treated in water vapor plasma at different processing powers. It was found that the upper layer of treated film with the thickness of 110 nm was changed into the black hydrogenated-TiO 2 with around 16 nm sized nanocystals during 10 min for dissipated power 200 W at room temperature. Analysis of the experimental results is used to obtain insights into the effects of water layer adsorbed on hydrophilic oxidized titanium surfaces exposed to plasma radiation.

  6. Desinfestação de substratos para produção de mudas, utilizando vapor de água Disinfesting substrate for transplants production employing hot water steam

    Directory of Open Access Journals (Sweden)

    João Bosco C. Silva

    2001-07-01

    Full Text Available O tratamento sanitário de substratos é uma operação importante no processo de produção de mudas e no cultivo de plantas em vasos ou outros contentores. Tradicionalmente tem-se utilizado o gás brometo de metila como agente desinfetante. Entretanto, a produção deste gás deverá ser abolida até o ano 2010, forçando-se a busca de novas opções. Desenvolveu-se na Embrapa Hortaliças um equipamento que utiliza o vapor de água à baixa pressão, produzido por uma caldeira industrial, com capacidade para evaporar 30 L/h de água, para aquecer o substrato contido em uma caixa metálica cilíndrica com capacidade de 2000 L. O vapor é aplicado no fundo da caixa que contém uma camada de brita coberta com uma tela metálica de malha de 2 mm, que favorece a distribuição uniforme do vapor por toda a massa de substrato. O tempo de aquecimento é de aproximadamente 3 horas e o calor armazenado durante este período mantém a massa de substrato aquecida a temperaturas pasteurizantes, por até 4 horas após a aplicação do vapor. Para testar a eficácia do sistema avaliou-se a sobrevivência dos patógenos Ralstonia solanacearum, Fusarium oxysporum, Sclerotinia sclerotiorum e Rhizoctonia solani. Aplicou-se vapor por uma hora, não considerando o período de aquecimento, e coletaram-se as amostras após uma, duas, três ou quatro horas o início da aplicação de vapor. O tratamento por uma hora, em adição ao período de aquecimento, resultou na eliminação dos patógenos.The disinfestation of substrate is an important process for transplanting production and for plant cultivation in pots or boxes. Traditionally, metyl bromide gas has been employed to eliminate microorganisms. However the production of bromide gas in Brazil will be interrupted by the year 2010 and it is necessary to search for new options. We have devised an equipment that utilizes hot steam water at low pressure produced into a boiler machine with the capacity of evaporating

  7. Unraveling the role of SiC or Si substrates in water vapor incorporation in SiO 2 films thermally grown using ion beam analyses

    Science.gov (United States)

    Corrêa, S. A.; Soares, G. V.; Radtke, C.; Stedile, F. C.

    2012-02-01

    The incorporation of water vapor in SiO 2 films thermally grown on 6H-SiC(0 0 0 1) and on Si (0 0 1) was investigated using nuclear reaction analyses. Water isotopically enriched in deuterium ( 2H or D) and in 18O was used. The dependence of incorporated D with the water annealing temperature and initial oxide thickness were inspected. The D amount in SiO 2/SiC structures increases continuously with temperature and with initial oxide thickness, being incorporated in the surface, bulk, and interface regions of SiO 2 films. However, in SiO 2/Si, D is observed mostly in near-surface regions of the oxide and no remarkable dependence with temperature or initial oxide thickness was observed. At any annealing temperature, oxygen from water vapor was incorporated in all depths of the oxide films grown on SiC, in contrast with the SiO 2/Si.

  8. Water vapor δ17O measurements using an off-axis integrated cavity output spectrometer and seasonal variation in 17O-excess of precipitation in the east-central United States

    Science.gov (United States)

    Tian, C.; Wang, L.; Novick, K. A.

    2016-12-01

    High-precision triple oxygen isotope analysis can be used to improve our understanding of multiple hydrological and meteorological processes. Recent studies focus on understanding 17O-excess variation of tropical storms, high-latitude snow and ice-core as well as spatial distribution of meteoric water (tap water). The temporal scale of 17O-excess variation in middle-latitude precipitation is needed to better understand which processes control on the 17O-excess variations. This study focused on assessing how the accuracy and precision of vapor δ17O laser spectroscopy measurements depend on vapor concentration, delta range, and averaging-time. Meanwhile, we presented 17O-excess data from two-year, event based precipitation sampling in the east-central United States. A Triple Water Vapor Isotope Analyzer (T-WVIA) was used to evaluate the accuracy and precision of δ2H, δ18O and δ17O measurements. GISP and SLAP2 from IAEA and four working standards were used to evaluate the sensitivity in the three factors. Overall, the accuracy and precision of all isotope measurements were sensitive to concentration, with higher accuracy and precision generally observed under moderate vapor concentrations (i.e., 10000-15000 ppm) for all isotopes. Precision was also sensitive to the range of delta values, though the effect was not as large when compared to the sensitivity to concentration. The precision was much less sensitive to averaging time when compared with concentration and delta range effects. The preliminary results showed that 17O-excess variation was lower in summer (23±17 per meg) than in winter (34±16 per meg), whereas spring values (30±21 per meg) was similar to fall (29±13 per meg). That means kinetic fractionation influences the isotopic composition and 17O-excess in different seasons.

  9. Airborne Observations of Water Vapor Deuterium Excess in the Mid-Latitude Lower Troposphere

    Science.gov (United States)

    Salmon, O. E.; Welp, L.; Shepson, P. B.; Stirm, B. H.

    2017-12-01

    Water vapor is responsible for over half of the natural atmospheric greenhouse effect. As global temperatures increase due to fossil fuel combustion, atmospheric water vapor concentrations are also expected to increase in positive feedback. Additionally, studies have shown that urban areas can influence humidity levels, and the frequency and intensity of precipitation events. It is thus important to understand anthropogenic modification of the hydrological cycle, particularly around urban areas, where over half of the world's population resides. Airborne measurements of water vapor isotopologues containing 2H and 18O were conducted to better understand processes influencing atmospheric moisture levels around urban areas. Airborne measurements were conducted around the Indianapolis and Washington, D.C.-Baltimore areas during afternoon hours in February and March 2016, using a Los Gatos Research Water Vapor Isotope Analyzer installed in Purdue University's experimental aircraft, the Airborne Laboratory for Atmospheric Research. The measurements of 2H and 18O allow for the calculation of deuterium excess (= δ2H - 8*δ18O), which provides information about non-equilibrium processes, such as kinetic effects, air parcel mixing, and transpiration. There are few studies that have reported observations of deuterium excess above the surface level ( 100 m). During the measurement campaign, vertical profiles were frequently conducted from 300 m above the ground to an altitude of approximately 1.5 km, effectively characterizing water vapor isotope profiles spanning the boundary layer and lower free troposphere. Measurements probed the transition from planetary boundary layer air to free troposphere air to provide high resolution deuterium excess information across this interface. Processes such as Rayleigh distillation, atmospheric mixing, and surface fluxes potentially impacting water vapor deuterium excess through the boundary layer and free troposphere with be discussed.

  10. Study on the interaction of lithium orthosilicate with water vapor and hydrogen

    International Nuclear Information System (INIS)

    Huber, S.

    1994-09-01

    The present work discusses the adsorption of H 2 O(g) as well as the reactions of D 2 O(g) and D 2 (g) with lithium orthosilicate (Li 4 SiO 4 ), a potential tritium breeding ceramic for future fusion reactors. An apparatus was constructed which permits H 2 O partial pressures as low as 1 μbar to be generated and subsequently measured with high accuracy and precision. Using the frontal analysis of gas chromatography, adsorption isotherms were determined at temperatures and water vapor pressures ranging from 653 to 1093 K and 1 to 10 μbar, respectively. Based upon the data, the tritium inventory at the surface of Li 4 SiO 4 (cr) can be estimated as function of temperature and water vapor concentration in the purge gas of a solid breeder blanket. The reactions of lithium orthosilicate with deuterium oxide and deuterium were studied at high temperature (1160 - 1420K) by means of Knudsen effusion mass spectrometry. In both cases the production of lithium hydroxide and the establishment of an equilibrium between LiOD(g) and D 2 O(g) were observed; D 2 O is derived from oxidation of deuterium, presumably under formation of a reduced surface layer. Equilibrium constants and reaction enthalpies were computed for the reaction of Li 4 SiO 4 (cr) with D 2 O(g). In addition, the vapor pressure of LiOD(g) above Li 4 SiO 4 (cr) was determined as function of temperature and deuterium oxide pressure. Further experiments with lithium orthosilicate were carried out under flowing hydrogen in order to analyze the effects of temperature, H 2 -concentration, gas flow, sample size and sample pretreatment on the formation of water vapor. The results confirm the mass spectrometric findings mentioned above. (orig.) [de

  11. Gas diffusion ultrabarriers on polymer substrates using Al2O3 atomic layer deposition and SiN plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Carcia, P. F.; McLean, R. S.; Groner, M. D.; Dameron, A. A.; George, S. M.

    2009-01-01

    Thin films grown by Al 2 O 3 atomic layer deposition (ALD) and SiN plasma-enhanced chemical vapor deposition (PECVD) have been tested as gas diffusion barriers either individually or as bilayers on polymer substrates. Single films of Al 2 O 3 ALD with thicknesses of ≥10 nm had a water vapor transmission rate (WVTR) of ≤5x10 -5 g/m 2 day at 38 deg. C/85% relative humidity (RH), as measured by the Ca test. This WVTR value was limited by H 2 O permeability through the epoxy seal, as determined by the Ca test for the glass lid control. In comparison, SiN PECVD films with a thickness of 100 nm had a WVTR of ∼7x10 -3 g/m 2 day at 38 deg. C/85% RH. Significant improvements resulted when the SiN PECVD film was coated with an Al 2 O 3 ALD film. An Al 2 O 3 ALD film with a thickness of only 5 nm on a SiN PECVD film with a thickness of 100 nm reduced the WVTR from ∼7x10 -3 to ≤5x10 -5 g/m 2 day at 38 deg. C/85% RH. The reduction in the permeability for Al 2 O 3 ALD on the SiN PECVD films was attributed to either Al 2 O 3 ALD sealing defects in the SiN PECVD film or improved nucleation of Al 2 O 3 ALD on SiN.

  12. Atmospheric Hydrodeoxygenation of Biomass Fast Pyrolysis Vapor by MoO3

    DEFF Research Database (Denmark)

    Zhou, Guofeng; Jensen, Peter Arendt; Le, Duy Michael

    2016-01-01

    was not significant at temperatures below 400 °C. At 450 °C catalyst temperature and 93 vol % H2 concentration, the wood pyrolysis vapor was more active toward cracking forming gas species instead of performing the desired HDO forming hydrocarbons. The lignin pyrolysis vapor was more resistant to cracking and yielded...... 16.2 wt %daf organic liquid, while achieving 52% degree of deoxygenation at 450 °C catalyst temperature under 89 vol % H2 concentration. The corresponding energy recovery in the liquid phase was 23.5%. The spent catalyst showed two deactivation routes, coke formation and reduction of MoO3 to MoO2......, which is inactive in HDO. The catalyst experienced severe reduction at temperatures higher than 400 °C. The yields of coke relative to the fed biomass were in the range of 3–4 wt %daf for lignin and 5–6 wt %daf for wood. Compared to untreated bio-oil the upgraded lignin organic liquid showed improved...

  13. What Good is Raman Water Vapor Lidar?

    Science.gov (United States)

    Whitman, David

    2011-01-01

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

  14. Linkages Among Water Vapor Flows, Food Production, and Terrestrial Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Johan Rockström

    1999-12-01

    Full Text Available Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3/yr (ranging from 56,000 to 84,000 km3/yr. Of this flow, 90% is attributed to forests, including woodlands (40,000 km3/yr, wetlands (1400 km3/yr, grasslands (15,100 km3/yr, and croplands (6800 km3/yr. These terrestrial biomes sustain society with essential welfare-supporting ecosystem services, including food production. By analyzing the freshwater requirements of an increasing demand for food in the year 2025, we discover a critical trade-off between flows of water vapor for food production and for other welfare-supporting ecosystem services. To reduce the risk of unintentional welfare losses, this trade-off must become embedded in intentional ecohydrological landscape management.

  15. Water vapor profiling using microwave radiometry

    Science.gov (United States)

    Wang, J. R.; Wilheit, T. T.

    1988-01-01

    Water vapor is one of the most important constituents in the Earth's atmosphere. Its spatial and temporal variations affect a wide spectrum of meteorological phenomena ranging from the formation of clouds to the development of severe storms. The passive microwave technique offers an excellent means for water vapor measurements. It can provide both day and night coverage under most cloud conditions. Two water vapor absorption features, at 22 and 183 GHz, were explored in the past years. The line strengths of these features differ by nearly two orders of magnitude. As a consequence, the techniques and the final products of water vapor measurements are also quite different. The research effort in the past few years was to improve and extend the retrieval algorithm to the measurements of water vapor profiles under cloudy conditions. In addition, the retrieval of total precipitable water using 183 GHz measurements, but in a manner analogous to the use of 22 GHz measurements, to increase measurement sensitivity for atmospheres of very low moisture content was also explored.

  16. Synthesis and characterization of beta-Ga2O3 nanorod array clumps by chemical vapor deposition.

    Science.gov (United States)

    Shi, Feng; Wei, Xiaofeng

    2012-11-01

    beta-Ga2O3 nanorod array clumps were successfully synthesized on Si (111) substrates by chemical vapor deposition. The composition, microstructure, morphology, and light-emitting property of these clumps were characterized by X-ray diffraction, Fourier transform infrared spectrophotometry, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and photoluminescence. The results demonstrate that the sample synthesized at 1050 degrees C for 15 min was composed of monoclinic beta-Ga2O3 nanorod array clumps, where each single nanorod was about 300 nm in diameter with some nano-droplets on its tip. These results reveal that the growth mechanism agrees with the vapor-liquid-solid (VLS) process. The photoluminescence spectrum shows that the Ga2O3 nanorods have a blue emission at 438 nm, which may be attributed to defects, such as oxygen vacancies and gallium-oxygen vacancy pairs. Defect-energy aggregation confinement growth theory was proposed to explain the growth mechanism of Ga2O3 nanorod array clumps collaborated with the VLS mechanism.

  17. Kinetic Requirements for the Measurement of Mesospheric Water Vapor at 6.8 (microns) under Non-LTE Conditions

    Science.gov (United States)

    Zhou, Daniel K.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Russell, James M., III

    1999-01-01

    We present accuracy requirements for specific kinetic parameters used to calculate the populations and vibrational temperatures of the H2O(010) and H2O(020) states in the terrestrial mesosphere. The requirements are based on rigorous simulations of the retrieval of mesospheric water vapor profiles from measurements of water vapor infrared emission made by limb scanning instruments on orbiting satellites. Major improvements in the rate constants that describe vibration-to- vibration exchange between the H2O(010) and 02(1) states are required in addition to improved specification of the rate of quenching Of O2(1) by atomic oxygen (0). It is also necessary to more accurately determine the yield of vibrationally excited O2(l) resulting from ozone photolysis. A contemporary measurement of the rate of quenching of H2O(010) by N2 and O2 is also desirable. These rates are either highly uncertain or have never before been measured at atmospheric temperatures. The suggested improvements are necessary for the interpretation of water vapor emission measurements at 6.8 microns to be made from a new spaceflight experiment in less than 2 years. The approach to retrieving water vapor under non-LTE conditions is also presented.

  18. Depletion-mode vertical Ga2O3 trench MOSFETs fabricated using Ga2O3 homoepitaxial films grown by halide vapor phase epitaxy

    Science.gov (United States)

    Sasaki, Kohei; Thieu, Quang Tu; Wakimoto, Daiki; Koishikawa, Yuki; Kuramata, Akito; Yamakoshi, Shigenobu

    2017-12-01

    We developed depletion-mode vertical Ga2O3 trench metal-oxide-semiconductor field-effect transistors by using n+ contact and n- drift layers. These epilayers were grown on an n+ (001) Ga2O3 single-crystal substrate by halide vapor phase epitaxy. Cu and HfO2 were used for the gate metal and dielectric film, respectively. The mesa width and gate length were approximately 2 and 1 µm, respectively. The devices showed good DC characteristics, with a specific on-resistance of 3.7 mΩ cm2 and clear current modulation. An on-off ratio of approximately 103 was obtained.

  19. Isotopic equilibrium between precipitation and water vapor: evidence from continental rains in central Kenya

    Science.gov (United States)

    Soderberg, K.; Gerlein, C.; Kemeny, P. C.; Caylor, K. K.

    2013-12-01

    An accurate understanding of the relationships between the isotopic composition of liquid water and that of water vapor in the environment can help describe hydrologic processes across many scales. One such relationship is the isotopic equilibrium between falling raindrops and the surrounding vapor. The degree of equilibration is used to model the isotopic composition of precipitation in isotope-enable general circulation models and land-atmosphere exchange models. Although this equilibrium has been a topic of isotope hydrology research for more than four decades, few studies have included vapor measurements to validate modeling efforts. Recent advances in laser technology have allowed for in situ vapor measurements at high temporal resolution (e.g., >1 Hz). Here we present concomitant rain and vapor measurements for a series of 17 rain events during the 'Continental' rainy season (June through August) at Mpala Research Center in central Kenya. Rain samples (n=218) were collected at intervals of 2 to 35 minutes (median of 3 minutes) depending on the rain rate (0.4 to 10.5 mm/hr). The volume-weighted mean rain values for δ18O, δ2H and D-excess (δ2H - 8* δ18O) were 0.1 ‰, 10.7 ‰, and 10.1 ‰. These values are more enriched than the annual weighted means reported for the area (-2.2 ‰, -7.6 ‰, and 11.0 ‰, respectively). Vapor was measured continuously at ~2Hz (DLT-100, Los Gatos Research), with an inverted funnel intake 4m above the ground surface. The mean vapor isotopic composition during the rain events was -10.0 +/- 1.2 ‰ (1 σ) for δ18O and -73.9 +/- 7.0 ‰ for δ2H. The difference between the rain sample isotopic composition and that of liquid in isotopic equilibrium with the corresponding vapor at the ambient temperature was 0.8 +/- 2.2 ‰ for δ18O and 6.2 +/- 7.0 ‰ for δ2H. This disequilibrium was found to correlate with the natural log of rain rate (R2 of 0.26 for δ18O and 0.46 for δ2H), with lower rain rates having larger

  20. Distribution of tropical tropospheric water vapor

    Science.gov (United States)

    Sun, De-Zheng; Lindzen, Richard S.

    1993-01-01

    Utilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence that constrains the turbulent downgradient mixing to within the convective boundary layer and effectively dries the troposphere through downward advection, it also pumps hydrometeors into the upper troposphere, whose subsequent evaporation appears to be the major source of moisture for the large-scale subsiding motion. The development of upper-level clouds and precipitation from these clouds may also act to dry the outflow, thus explaining the low relative humidity near the tropopause. A one-dimensional model is developed to simulate the mean vertical structure of water vapor in the tropical troposphere. It is also shown that the horizontal variation of water vapor in the tropical troposphere above the trade-wind boundary layer can be explained by the variation of a moisture source that is proportional to the amount of upper-level clouds. Implications for the nature of water vapor feedback in global warming are discussed.

  1. Superconductor thin films: topotactic corrosion mechanism of YBa2Cu3O7 with water vapor

    International Nuclear Information System (INIS)

    Boerner, R.; Schoellhorn, R.; Kabius, B.; Schubert, J.

    1995-01-01

    Corrosion in high-T c superconductors (HTSC) caused by water vapor is examined. HTSC thin films prepared using the laser ablation technique are shown to lose their superconducting properties due to the topotactic formation of a new hydroxylated phase which is a result of the corrosion. The mechanism of the corrosion process, which could be important in future applications of HTSC, is discussed. (orig.)

  2. Trends of total water vapor column above the Arctic from satellites observations

    Science.gov (United States)

    Alraddawi, Dunya; Sarkissian, Alain; Keckhut, Philippe; Bock, Olivier; Claud, Chantal; Irbah, Abdenour

    2016-04-01

    Atmospheric water vapor (H2O) is the most important natural (as opposed to man-made) greenhouse gas, accounting for about two-thirds of the natural greenhouse effect. Despite this importance, its role in climate and its reaction to climate change are still difficult to assess. Many details of the hydrological cycle are poorly understood, such as the process of cloud formation and the transport and release of latent heat contained in the water vapor. In contrast to other important greenhouse gases like carbon dioxide (CO2) and methane, water vapor has a much higher temporal and spatial variability. Total precipitable water (TPW) or the total column of water vapor (TCWV) is the amount of liquid water that would result if all the water vapor in the atmospheric column of unit area were condensed. TCWV distribution contains valuable information on the vigor of the hydrological processes and moisture transport in the atmosphere. Measurement of TPW can be obtained based on atmospheric water vapor absorption or emission of radiation in the spectral range from UV to MW. TRENDS were found over the terrestrial Arctic by means of TCWV retrievals (using Moderate Resolution Imaging Spectro-radiometer (MODIS) near-infrared (2001-2015) records). More detailed approach was made for comparisons with ground based instruments over Sodankyla - Finland (TCWV from: SCIAMACHY 2003-2011, GOME-2A 2007-2011, SAOZ 2003-2011, GPS 2003-2011, MODIS 2003-2011)

  3. Global lower mesospheric water vapor revealed by LIMS observations

    Science.gov (United States)

    Gordley, L. L.; Russell, J. M., III; Remsberg, E. E.

    1985-01-01

    The Limb Infrared Monitor of the Stratospheric water vapor channel data analysis has been extended from the 1. mb level (about 48 km) to the .3 mb level (about 60 km) through a radiance averaging procedure and better understanding of systematic errors. The data show H2O mixing ratio peaks near the .5 mb level varying from 4 to 7 ppmv with latitude and season. Above this level the mixing ratio drops off quickly with altitude, but, due to experimental uncertainties, at an uncertain rate. The stratospheric results are virtually the same as determined from the archived LIMS results with a tropical hygropause and enhanced H2O concentration in the lower levels at high winter latitudes.

  4. MODIS/Terra Aerosol Cloud Water Vapor Ozone Monthly L3 Global 1Deg CMG V006

    Data.gov (United States)

    National Aeronautics and Space Administration — MODIS/Terra Aerosol Cloud Water Vapor Ozone Monthly L3 Global 1Deg CMG (MOD08_M3). MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am...

  5. Validation of MIPAS IMK/IAA temperature, water vapor, and ozone profiles with MOHAVE-2009 campaign measurements

    Directory of Open Access Journals (Sweden)

    G. P. Stiller

    2012-02-01

    Full Text Available MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT, Institute for Meteorology and Climate Research (IMK and CSIC, Instituto de Astrofísica de Andalucía (IAA and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infra-red (FTIR spectrometers. For MIPAS temperatures (version V4O_T_204, no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203 is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause, but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202 has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution

  6. Validation of MIPAS IMK-IAA Temperature, Water Vapor, and Ozone Profiles with MOHAVE-2009 Campaign Measurements

    Science.gov (United States)

    Stiller, Gabrielle; Kiefer, M.; Eckert, E.; von Clarmann, T.; Kellmann, S.; Garcia-Comas, M.; Funke, B.; Leblanc, T.; Fetzer, E.; Froidevaux, L.; hide

    2012-01-01

    MIPAS observations of temperature, water vapor, and ozone in October 2009 as derived with the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK) and CSIC, Instituto de Astrofisica de Andalucia (IAA) and retrieved from version 4.67 level-1b data have been compared to co-located field campaign observations obtained during the MOHAVE-2009 campaign at the Table Mountain Facility near Pasadena, California in October 2009. The MIPAS measurements were validated regarding any potential biases of the profiles, and with respect to their precision estimates. The MOHAVE-2009 measurement campaign provided measurements of atmospheric profiles of temperature, water vapor/relative humidity, and ozone from the ground to the mesosphere by a suite of instruments including radiosondes, ozonesondes, frost point hygrometers, lidars, microwave radiometers and Fourier transform infrared (FTIR) spectrometers. For MIPAS temperatures (version V4O_T_204), no significant bias was detected in the middle stratosphere; between 22 km and the tropopause MIPAS temperatures were found to be biased low by up to 2 K, while below the tropopause, they were found to be too high by the same amount. These findings confirm earlier comparisons of MIPAS temperatures to ECMWF data which revealed similar differences. Above 12 km up to 45 km, MIPAS water vapor (version V4O_H2O_203) is well within 10% of the data of all correlative instruments. The well-known dry bias of MIPAS water vapor above 50 km due to neglect of non-LTE effects in the current retrievals has been confirmed. Some instruments indicate that MIPAS water vapor might be biased high by 20 to 40% around 10 km (or 5 km below the tropopause), but a consistent picture from all comparisons could not be derived. MIPAS ozone (version V4O_O3_202) has a high bias of up to +0.9 ppmv around 37 km which is due to a non-identified continuum like radiance contribution. No further

  7. Chemical Vapor Transport Deposition of Molybdenum Disulfide Layers Using H2O Vapor as the Transport Agent

    Directory of Open Access Journals (Sweden)

    Shichao Zhao

    2018-02-01

    Full Text Available Molybdenum disulfide (MoS2 layers show excellent optical and electrical properties and have many potential applications. However, the growth of high-quality MoS2 layers is a major bottleneck in the development of MoS2-based devices. In this paper, we report a chemical vapor transport deposition method to investigate the growth behavior of monolayer/multi-layer MoS2 using water (H2O as the transport agent. It was shown that the introduction of H2O vapor promoted the growth of MoS2 by increasing the nucleation density and continuous monolayer growth. Moreover, the growth mechanism is discussed.

  8. MODIS/Terra Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG V006

    Data.gov (United States)

    National Aeronautics and Space Administration — MODIS/Terra Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG (MOD08_D3). MODIS was launched aboard the Terra satellite on December 18, 1999 (10:30 am equator...

  9. MODIS/Aqua Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG V006

    Data.gov (United States)

    National Aeronautics and Space Administration — MODIS/Aqua Aerosol Cloud Water Vapor Ozone Daily L3 Global 1Deg CMG (MYD08_D3). MODIS was launched aboard the Aqua satellite on May 04, 2002 (1:30 pm equator...

  10. Cumulus convection and the terrestrial water-vapor distribution

    Science.gov (United States)

    Donner, Leo J.

    1988-01-01

    Cumulus convection plays a significant role in determining the structure of the terrestrial water vapor field. Cumulus convection acts directly on the moisture field by condensing and precipitating water vapor and by redistributing water vapor through cumulus induced eddy circulations. The mechanisms by which cumulus convection influences the terrestrial water vapor distribution is outlined. Calculations using a theory due to Kuo is used to illustrate the mechanisms by which cumulus convection works. Understanding of these processes greatly aids the ability of researchers to interpret the seasonal and spatial distribution of atmospheric water vapor by providing information on the nature of sources and sinks and the global circulation.

  11. Mass spectrometric study of Nd2S3 vaporization

    International Nuclear Information System (INIS)

    Fenochka, B.V.

    1987-01-01

    The authors conduct a mass-spectrometric study of neodymium(III) sulfide vaporization. The chemical composition of the samples was stoichiometric and the samples were vaporized from tantalum effusion cells. When the vapor over Nd 2 S 3 is ionized by electrons the mass spectra shows monovalent cations of Nd, S, NdS, and NdO. The enthalpy of vaporization if Nd atoms from Nd 2 S 3 at average experimental temperatures and the standard enthalpy of reaction is shown. Also presented is the enthalpy of vaporization of NdS molecules from Nd 2 S 3 at average experimental temperatures and the standard enthalpy of reaction

  12. Zonally resolved impact of ENSO on the stratospheric circulation and water vapor entry values

    Science.gov (United States)

    Konopka, Paul; Ploeger, Felix; Tao, Mengchu; Riese, Martin

    2016-10-01

    Based on simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) for the period 1979-2013, with model transport driven by the ECMWF ERA-Interim reanalysis, we discuss the impact of the El Niño Southern Oscillation (ENSO) on the variability of the dynamics, water vapor, ozone, and mean age of air (AoA) in the tropical lower stratosphere during boreal winter. Our zonally resolved analysis at the 390 K potential temperature level reveals that not only (deseasonalized) ENSO-related temperature anomalies are confined to the tropical Pacific (180-300°E) but also anomalous wave propagation and breaking, as quantified in terms of the Eliassen-Palm (EP) flux divergence, with strongest local contribution during the La Niña phase. This anomaly is coherent with respective anomalies of water vapor (±0.5 ppmv) and ozone (±100 ppbv) derived from CLaMS being in excellent agreement with the Aura Microwave Limb Sounder observations. Thus, during El Niño a more zonally symmetric wave forcing drives a deep branch of the Brewer-Dobson (BD) circulation. During La Niña this forcing increases at lower levels (≈390 K) over the tropical Pacific, likely influencing the shallow branch of the BD circulation. In agreement with previous studies, wet (dry) and young (old) tape recorder anomalies propagate upward in the subsequent months following El Niño (La Niña). Using CLaMS, these anomalies are found to be around +0.3 (-0.2) ppmv and -4 (+4) months for water vapor and AoA, respectively. The AoA ENSO anomaly is more strongly affected by the residual circulation (≈2/3) than by eddy mixing (≈1/3).

  13. Raman study of the effect of water vapor during low-temperature annealing on the structure and electrophysical properties of YBa{sub 2}Cu{sub 3}O{sub y}

    Energy Technology Data Exchange (ETDEWEB)

    Bobylev, I.B., E-mail: bobylev@imp.uran.ru; Ponosov, Yu.S.; Zyuzeva, N.A.

    2015-11-01

    The effects of an interaction of YBa{sub 2}Cu{sub 3}O{sub y} (123) with water vapors at a temperature 200 °C on the structure and electrophysical properties of the compound have been examined by Raman spectroscopy. It has been found that the penetration of water into the 123-type causes the transition of the compound from an oxide to a hydride-oxide-hydroxide, which is accompanied with transformation to the 124 pseudotype phase. Direct evidence has been obtained for the incorporation of OH{sup −}-groups in the 123-structure. After the interaction with water, the materials with high oxygen content (y ≥ 6.5) retain their superconductivity and exhibit two-magnon scattering in Raman spectra, which is not typical for them. Short-term recovery annealing followed by oxidation removes the water from the compound structure, which leads to the disappearance of the spin fluctuation spectra. At the same time, the structural defects are partially preserved. These manifest themselves through some peculiarities in the Raman spectra and are apparently pinning centers of magnetic vortices. A model of a splitting of the Cu–O chains and a formation of the 124-like phase in water-intercalated 123-structure has been proposed. This mechanism supposes the dissociation of the OH{sup −}-groups and the filling in the copper vacancies by protons. - Highlights: • Absorbing water at 200 °C, the Y-123 ceramics transforms to H{sub x}YBa{sub 2}Cu{sub 3}O{sub y}(OH){sub z}. • The incorporation of water in the Y-123 (y ≥ 6.5) leads to the well magnetic peak. • For the Y-123 with y < 6.5 the OH{sup −}-groups occupy the vacancies of several types. • The OH{sup −}-groups are oriented along the c-axis.

  14. Optimization of GPS water vapor tomography technique with radiosonde and COSMIC historical data

    Directory of Open Access Journals (Sweden)

    S. Ye

    2016-09-01

    Full Text Available The near-real-time high spatial resolution of atmospheric water vapor distribution is vital in numerical weather prediction. GPS tomography technique has been proved effectively for three-dimensional water vapor reconstruction. In this study, the tomography processing is optimized in a few aspects by the aid of radiosonde and COSMIC historical data. Firstly, regional tropospheric zenith hydrostatic delay (ZHD models are improved and thus the zenith wet delay (ZWD can be obtained at a higher accuracy. Secondly, the regional conversion factor of converting the ZWD to the precipitable water vapor (PWV is refined. Next, we develop a new method for dividing the tomography grid with an uneven voxel height and a varied water vapor layer top. Finally, we propose a Gaussian exponential vertical interpolation method which can better reflect the vertical variation characteristic of water vapor. GPS datasets collected in Hong Kong in February 2014 are employed to evaluate the optimized tomographic method by contrast with the conventional method. The radiosonde-derived and COSMIC-derived water vapor densities are utilized as references to evaluate the tomographic results. Using radiosonde products as references, the test results obtained from our optimized method indicate that the water vapor density accuracy is improved by 15 and 12 % compared to those derived from the conventional method below the height of 3.75 km and above the height of 3.75 km, respectively. Using the COSMIC products as references, the results indicate that the water vapor density accuracy is improved by 15 and 19 % below 3.75 km and above 3.75 km, respectively.

  15. On the Quality of the Nimbus 7 LIMS Version 6 Water Vapor Profiles and Distributions

    Science.gov (United States)

    Remsberg, E. E.; Natarajan, M.; Lingenfelser, G. S.; Thompson, R. E.; Marshall, B. T.; Gordley, L. L.

    2009-01-01

    This report describes the quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) water vapor (H2O) profiles of 1978/79 that were processed with a Version 6 (V6) algorithm and archived in 2002. The V6 profiles incorporate a better knowledge of the instrument attitude for the LIMS measurements along its orbits, leading to improvements for its temperature profiles and for the registration of its water vapor radiances with pressure. As a result, the LIMS V6 zonal-mean distributions of H2O exhibit better hemispheric symmetry than was the case from the original Version 5 (V5) dataset that was archived in 1982. Estimates of the precision and accuracy of the V6 H2O profiles are developed and provided. Individual profiles have a precision of order 5% and an estimated accuracy of about 19% at 3 hPa, 14% at 10 hPa, and 26% at 50 hPa. Profile segments within about 2 km of the tropopause are often affected by emissions from clouds that appear in the finite field-of-view of the detector for the LIMS H2O channel. Zonally-averaged distributions of the LIMS V6 H2O are compared with those from the more recent Microwave Limb Sounder (MLS) satellite experiment for November, February, and May of 2004/2005. The patterns and values of their respective distributions are similar in many respects. Effects of a strengthened Brewer-Dobson circulation are indicated in the MLS distributions of the recent decade versus those of LIMS from 1978/79. A tropical tape recorder signal is present in the 7-month time series of LIMS V6 H2O with lowest values in February 1979, and the estimated, annually-averaged "entry-level" H2O is 3.5 to 3.8 ppmv. It is judged that this historic LIMS water vapor dataset is of good quality for studies of the near global-scale chemistry and transport for pressure levels from 3 hPa to about 70 to 100 hPa.

  16. Water vapor differential absorption lidar development and evaluation

    Science.gov (United States)

    Browell, E. V.; Wilkerson, T. D.; Mcllrath, T. J.

    1979-01-01

    A ground-based differential absorption lidar (DIAL) system is described which has been developed for vertical range-resolved measurements of water vapor. The laser transmitter consists of a ruby-pumped dye laser, which is operated on a water vapor absorption line at 724.372 nm. Part of the ruby laser output is transmitted simultaneously with the dye laser output to determine atmospheric scattering and attenuation characteristics. The dye and ruby laser backscattered light is collected by a 0.5-m diam telescope, optically separated in the receiver package, and independently detected using photomultiplier tubes. Measurements of vertical water vapor concentration profiles using the DIAL system at night are discussed, and comparisons are made between the water vapor DIAL measurements and data obtained from locally launched rawinsondes. Agreement between these measurements was found to be within the uncertainty of the rawinsonde data to an altitude of 3 km. Theoretical simulations of this measurement were found to give reasonably accurate predictions of the random error of the DIAL measurements. Confidence in these calculations will permit the design of aircraft and Shuttle DIAL systems and experiments using simulation results as the basis for defining lidar system performance requirements

  17. Sorption of water vapor in partially hydrolyzed poly(vinyl acetate)

    International Nuclear Information System (INIS)

    Spencer, H.G.; Honeycutt, S.C.

    1973-01-01

    The sorption kinetics of H 2 O and D 2 O in copolymers of partially hydrolyzed poly(vinyl acetate) were studied and compared with the sorption kinetics of vinyl acetate--vinyl alcohol copolymers, and poly(vinyl alcohol). The special measurement problems presented by transient-state sorption studies in water vapor--polymer systems and their effects on the results are discussed

  18. Portable device for generation of ultra-pure water vapor feeds

    Science.gov (United States)

    Velin, P.; Stenman, U.; Skoglundh, M.; Carlsson, P.-A.

    2017-11-01

    A portable device for the generation of co-feeds of water vapor has been designed, constructed, and evaluated for flexible use as an add-on component to laboratory chemical reactors. The vapor is formed by catalytic oxidation of hydrogen, which benefits the formation of well-controlled minute concentrations of ultra-pure water. Analysis of the effluent stream by on-line mass spectrometry and Fourier transform infrared spectroscopy confirms that water vapor can be, with high precision, generated both rapidly and steadily over extended periods in the range of 100 ppm to 3 vol. % (limited by safety considerations) using a total flow of 100 to 1500 ml/min at normal temperature and pressure. Further, the device has been used complementary to a commercial water evaporator and mixing system to span water concentrations up to 12 vol. %. Finally, an operando diffuse reflective infrared Fourier transform spectroscopic measurement of palladium catalysed methane oxidation in the absence and presence of up to 1.0 vol. % water has been carried out to demonstrate the applicability of the device for co-feeding well-controlled low concentrations of water vapor to a common type of spectroscopic experiment. The possibilities of creating isotopically labeled water vapor as well as using tracer gases for dynamic experiments are discussed.

  19. Controls on water vapor isotopes over Roorkee, India: Impact of convective activities and depression systems

    Science.gov (United States)

    Saranya, P.; Krishan, Gopal; Rao, M. S.; Kumar, Sudhir; Kumar, Bhishm

    2018-02-01

    The study evaluates the water vapor isotopic compositions and its controls with special reference to Indian Summer Monsoon (ISM) season at Roorkee, India. Precipitation is usually a discrete event spatially and temporally in this part of the country, therefore, the information provided is limited, while, the vapors have all time availability and have a significant contribution in the hydrological cycle locally or over a regional scale. Hence for understanding the processes altering the various sources, its isotopic signatures were studied. The Isotope Water Vapour Line (Iso Val) was drawn together with the Global Meteoric Water Line (GMWL) and the best fit line was δD = 5.42 * δ18O + 27.86. The precipitation samples were also collected during the study period and were best fitted with δD = 8.20(±0.18) * δ18O + 9.04(±1.16) in the Local Meteoric Water Line (LMWL). From the back trajectory analysis of respective vapor samples, it is unambiguous that three major sources viz; local vapor, western disturbance and monsoon vapor are controlling the fate of moisture over Roorkee. The d-excess in ground-level vapor (GLV) reveals the supply of recycled moisture from continental water bodies and evapo-transpiration as additional moisture sources to the study area. The intensive depletion in isotopic ratios was associated with the large-scale convective activity and low-pressure/cyclonic/depression systems formed over Bay of Bengal.

  20. Oxidative vaporization kinetics of Cr2O3 in oxygen from 1000 to 1300 C

    Science.gov (United States)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.

    1974-01-01

    Rates of oxidative vaporization of Cr2O3 on preoxidized resistively heated chromium were determined in flowing oxygen at a pressure of 0.115 Torr for temperatures from 1000 to 1300 C. Reaction controlled rates were obtained from experimental rates by a gold calibration technique, and these rates were shown to agree with those predicted by thermochemical analysis. The activation energy obtained for the oxidative vaporization reaction corresponded numerically with the thermochemical enthalpy of the reaction. A theoretical equation is given for calculating the rate from thermodynamic data using boundary-layer theory.

  1. Mars atmospheric water vapor abundance: 1996-1997

    Science.gov (United States)

    Sprague, A. L.; Hunten, D. M.; Doose, L. R.; Hill, R. E.

    2003-05-01

    Measurements of martian atmospheric water vapor made throughout Ls = 18.0°-146.4° (October 3, 1996-July 12, 1997) show changes in Mars humidity on hourly, daily, and seasonal time scales. Because our observing program during the 1996-1997 Mars apparition did not include concomitant measurement of nearby CO 2 bands, high northern latitude data were corrected for dust and aerosol extinction assuming an optical depth of 0.8, consistent with ground-based and HST imaging of northern dust storms. All other measurements with airmass greater than 3.5 were corrected using a total optical depth of 0.5. Three dominant results from this data set are as follows: (1) pre- and post-opposition measurements made with the slit crossing many hours of local time on Mars' Earth-facing disk show a distinct diurnal pattern with highest abundances around and slightly after noon with low abundances in the late afternoon, (2) measurements of water vapor over the Mars Pathfinder landing site (Carl Sagan Memorial Station) on July 12, 1997, found 21 ppt μm in the spatial sector centered near 19° latitude, 36° longitude while abundances around the site varied from as low as 6 to as high as 28 ppt μm, and (3) water vapor abundance is patchy on hourly and daily time scales but follows the usual seasonal trends.

  2. Fourier transform measurements of water vapor line parameters in the 4200-6600 cm{sup -1} region

    Energy Technology Data Exchange (ETDEWEB)

    Jenouvrier, Alain [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France)]. E-mail: alain.jenouvrier@univ-reims.fr; Daumont, Ludovic [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France); Regalia-Jarlot, Laurence [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France); Tyuterev, Vladimir G. [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France); Carleer, Michel [Service de Chimie Quantique et de Photophysique, CP 160/09, Universite Libre de Bruxelles, 50 Av. F.D. Roosevelt, B-1050 Brussels (Belgium); Vandaele, Ann Carine [Institut d' Aeronomie Spatiale de Belgique, Av. Circulaire 3, B-1180 Brussels (Belgium); Mikhailenko, Semen [Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, Russian Academy of Sciences, 1, Av. Akademichesskii, 634055 Tomsk (Russian Federation); Fally, Sophie [Service de Chimie Quantique et de Photophysique, CP 160/09, Universite Libre de Bruxelles, 50 Av. F.D. Roosevelt, B-1050 Brussels (Belgium)

    2007-06-15

    New high-resolution water vapor absorption spectra were obtained at room temperature in the 4200-6600 cm{sup -1} spectral region by combining Fourier transform spectrometers (FTS) with single and multiple reflection cells. With absorption paths from 0.3 to 1800 m in pure and air diluted water vapor, accurate measurements of about 10400 lines in an intensity range from 10{sup -29} to 10{sup -19} cm/molecule have been performed. Positions, intensities, self- and air-broadening coefficients and air-induced shifts were determined for the H{sub 2} {sup 16}O, H{sub 2} {sup 17}O, H{sub 2} {sup 18}O and HDO isotopologues. The rovibrational assignment of the observed lines was performed with the use of global variational predictions and allowed the identification of several new energy levels. One major contribution of this work consists of the identification of 3280 new weak lines. A very close agreement between the new measured parameters and those listed in the database is reported as well as between the observations and the most recent variational calculations for the positions and the intensities. The present parameters provide an extended and homogeneous data set for water vapor, which is shown to significantly improve the databases for atmospheric applications, especially in the transmission windows on both sides of the band centered at 5400 cm{sup -1}.

  3. Reaction of water vapor with a clean liquid uranium surface

    International Nuclear Information System (INIS)

    Siekhaus, W.

    1985-01-01

    To study the reaction of water vapor with uranium, we have exposed clean liquid uranium surfaces to H 2 O under UHV conditions. We have measured the surface concentration of oxygen as a function of exposure, and determined the maximum attainable surface oxygen concentration X 0 /sup s/ as a function of temperature. We have used these measurements to estimate, close to the melting point, the solubility of oxygen (X 0 /sup b/, -4 ) and its surface segregation coefficient β/sup s/(> 10 3 ). 8 refs., 5 figs., 1 tab

  4. Mass spectrometric study of vaporization of (U,Pu)O2 fuel simulating high burnup

    International Nuclear Information System (INIS)

    Maeda, Atsushi; Ohmichi, Toshihiko; Fukushima, Susumu; Handa, Muneo

    1985-08-01

    The vaporization behavior of (U,Pu)O 2 fuel simulatig high burnup was studied in the temperature range of 1,573 -- 2,173 K by high temperature mass spectrometry. The phases in the simulated fuel were examined by X-ray microprobe analysis. The relationship between chemical form and vaporization behavior of simulated fission product elements was discussed. Pd, Sr, Ba, Ce and actinide-bearing vapor species were observed, and it was clarified that Pd vapor originated from metallic inclusion and Sr and Ce vapors, from mixed oxide fuel matrix. The vaporization behavior of the actinide elements was somewhat similar to that of hypostoichiometric mixed oxide fuel. The behavior of Ba-bearing vapor species changed markedly over about 2,000 K. From the determination of BaO vapor pressures over simulated fuel and BaZrO 3 , it was revealed thermodynamically that the transformation of the chemical form of Ba about 2,000 K, i.e., dissolution of BaZrO 3 phase into fuel matrix, might be the reason of the observed vapor pressure change. (author)

  5. Liquids - vapor and liquids - solids equilibria in the system Th(NO3)4 - UO2(NO3)2 - HNO3 - H2O

    International Nuclear Information System (INIS)

    Volk, V.I.; Vakhrushin, A.Yu.; Mamaev, S.L.; Zhirnov, Yu.P.

    1999-01-01

    Liquids - vapor and liquids - solids equilibria in the system Th(NO 3 ) 4 - UO 2 (NO 3 ) 2 - HNO 3 - H 2 O were investigated. It was established that in this system thorium nitrate hexahydrate and uranyl nitrate hexa- and trihydrate are formed. Empiric equations of solubility isotherm at 25 deg C were found. Densities of liquid phases of the system were determined. It was established that uranyl nitrates and thorium nitrates salt out nitric acid in vapor phase just as separately so in the case of mutual presence. Empiric equation fixing relationship between nitric acid concentration in condensed phase and concentrations of all components in liquid phase was found

  6. Epitaxial growth of SrTiO3/YBa2Cu3O7 - x heterostructures by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Liang, S.; Chern, C. S.; Shi, Z. Q.; Lu, P.; Safari, A.; Lu, Y.; Kear, B. H.; Hou, S. Y.

    1994-06-01

    We report heteroepitaxial growth of SrTiO3 on YBa2Cu3O7-x/LaAlO3 substrates by plasma-enhanced metalorganic chemical vapor deposition. X-ray diffraction results indicated that SrTiO3 films were epitaxially grown on a (001) YBa2Cu3O7-x surface with [100] orientation perpendicular to the surface. The film composition, with Sr/Ti molar ratio in the range of 0.9 to 1.1, was determined by Rutherford backscattering spectrometry and energy dispersive spectroscopy. The thickness of the SrTiO3 films is 0.1-0.2 μm. The epitaxial growth was further evidenced by high-resolution transmission electron microscopy and selected area diffraction. Atomically abrupt SrTiO3/YBa2Cu3O7-x interface and epitaxial growth with [100]SrTiO3∥[001]YBa2Cu3O7-x were observed in this study. The superconducting transition temperature of the bottom YBa2Cu3O7-x layer, as measured by ac susceptometer, did not significantly degrade after the growth of overlayer SrTiO3. The capacitance-voltage measurements showed that the dielectric constant of the SrTiO3 films was as high as 315 at a signal frequency of 100 KHz. The leakage current density through the SrTiO3 films is about 1×10-6 A/cm2 at 2-V operation. Data analysis on the current-voltage characteristic indicated that the conduction process is related to bulk-limited Poole-Frenkel emission.

  7. MODIS/Aqua Aerosol Cloud Water Vapor Ozone 8-Day L3 Global 1Deg CMG V006

    Data.gov (United States)

    National Aeronautics and Space Administration — MODIS/Aqua Aerosol Cloud Water Vapor Ozone 8-Day L3 Global 1Deg CMG (MYD08_E3). MODIS was launched aboard the Aqua satellite on May 04, 2002 (1:30 pm equator...

  8. Cassini/CIRS Observations of Water Vapor in Titan's Stratosphere

    Science.gov (United States)

    Bjoraker, Gordon L.; Achterberg, R. K.; Anderson, C. M.; Samuelson, R. E.; Carlson, R. C.; Jennings, D. E.

    2008-01-01

    The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft has obtained spectra of Titan during most of the 44 flybys of the Cassini prime mission. Water vapor on Titan was first detected using whole-disk observations from the Infrared Space Observatory (Coustenis et al 1998, Astron. Astrophys. 336, L85-L89). CIRS data permlt the retrieval of the latitudinal variation of water on Titan and some limited information on its vertical profile. Emission lines of H2O on Titan are very weak in the CIRS data. Thus, large spectral averages as well as improvements in calibration are necessary to detect water vapor. Water abundances were retrieved in nadir spectra at 55 South, the Equator, and at 19 North. Limb spectra of the Equator were also modeled to constrain the vertical distribution of water. Stratospheric temperatures in the 0.5 - 4.0 mbar range were obtained by inverting spectra of CH4 in the v4 band centered at 1304/cm. The temperature in the lower stratosphere (4 - 20 mbar) was derived from fitting pure rotation lines of CH4 between 80 and 160/cm. The origin of H2O and CO2 is believed to be from the ablation of micrometeorites containing water ice, followed by photochemistry. This external source of water originates either within the Saturn system or from the interplanetary medium. Recently, Horst et al (J. Geophys. Res. 2008, in press) developed a photochemical model of Titan in which there are two external sources of oxygen. Oxygen ions (probably from Enceladus) precipitate into Titan's atmosphere to form CO at very high altitudes (1100 km). Water ice ablation at lower altitudes (700 km) forms H2O and subsequent chemistry produces CO2. CIRS measurements of CO, CO2, and now of H2O will provide valuable constraints to these photochemical models and - improve our understanding of oxygen chemistry on Titan.

  9. Vacuum distillation/vapor filtration water recovery

    Science.gov (United States)

    Honegger, R. J.; Neveril, R. B.; Remus, G. A.

    1974-01-01

    The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

  10. Water-vapor-enhanced growth of Ge-GeOx core-shell nanowires and Si1-xGexOy nanowires

    International Nuclear Information System (INIS)

    Hsu, T-J; Ko, C-Y; Lin, W-T

    2007-01-01

    The effects of moist Ar on the growth of Ge-GeO x core-shell nanowires (Ge-GeO x NWs) and Si 1-x Ge x O y nanowires (SiGeONWs) on Si substrates without adding a metal catalyst via the carbothermal reduction of GeO 2 powders at 1100 deg. C were studied. No significant nanowires were grown in dry Ar at a flow rate of 100-300 sccm until a bit of water in the range of 0.5-2 ml was loaded into the furnace. More water suppressed the growth of nanowires because of the exhaustion of more graphite powder. The growth of Ge-GeO x NWs and SiGeONWs follows the vapor-solid and vapor-liquid-solid processes, respectively. The present study showed that the water vapor serves as an oxidizer as well as a reducer at 1100 deg. C in enhancing the growth of SiGeONWs and Ge-GeO x NWs, respectively. The growth mechanisms of Ge-GeO x NWs and SiGeONWs are also discussed

  11. Water Vapor Remote Sensing Techniques: Radiometry and Solar Spectrometry

    Science.gov (United States)

    Somieski, A.; Buerki, B.; Cocard, M.; Geiger, A.; Kahle, H.-G.

    The high variability of atmospheric water vapor content plays an important role in space geodesy, climatology and meteorology. Water vapor has a strong influence on transatmospheric satellite signals, the Earth's climate and thus the weather forecasting. Several remote sensing techniques have been developed for the determination of inte- grated precipitable water vapor (IPWV). The Geodesy and Geodynamics Lab (GGL) utilizes the methods of Water Vapor Radiometry and Solar Spectrometry to quantify the amount of tropospheric water vapor and its temporal variations. The Water Vapor Radiometer (WVR) measures the radiation intensity of the atmosphere in a frequency band ranging from 20 to 32 GHz. The Solar Atmospheric MOnitoring Spectrome- ter (SAMOS) of GGL is designed for high-resolution measurements of water vapor absorption lines using solar radiation. In the framework of the ESCOMPTE (ExpÊrience sur Site pour COntraindre les Mod- Éles de Pollution atmosphÊrique et de Transport d'Emissions) field campaign these instruments have been operated near Marseille in 2001. They have aquired a long time series of integrated precipitable water vapor content (IPWV). The accuracy of IPWV measured by WVR and SAMOS is 1 kg/m2. Furthermore meteorological data from radiosondes were used to calculate the IPWV in order to provide comparisons with the results of WVR and SAMOS. The methods of Water Vapor Radiometry and So- lar Spectrometry will be discussed and first preliminary results retrieved from WVR, SAMOS and radiosondes during the ESCOMPTE field campaign will be presented.

  12. Evaluating the skills of isotope-enabled general circulation models against in situ atmospheric water vapor isotope observations

    DEFF Research Database (Denmark)

    Steen-Larsen, Hans Christian; Risi, C.; Werner, M.

    2017-01-01

    The skills of isotope-enabled general circulation models are evaluated against atmospheric water vapor isotopes. We have combined in situ observations of surface water vapor isotopes spanning multiple field seasons (2010, 2011, and 2012) from the top of the Greenland Ice Sheet (NEEM site: 77.45°N......: 2014). This allows us to benchmark the ability to simulate the daily water vapor isotope variations from five different simulations using isotope-enabled general circulation models. Our model-data comparison documents clear isotope biases both on top of the Greenland Ice Sheet (1-11% for δ18O and 4...... boundary layer water vapor isotopes of the Baffin Bay region show strong influence on the water vapor isotopes at the NEEM deep ice core-drilling site in northwest Greenland. Our evaluation of the simulations using isotope-enabled general circulation models also documents wide intermodel spatial...

  13. Investigation of tungsten mass transfer in rarefied air oxygen and water vapors

    International Nuclear Information System (INIS)

    Evsikov, A.S.; Makeev, A.A.; Lyubimova, L.L.; Sinyavskij, V.V.

    1989-01-01

    The results of experimental investigations of oxygen and water vapor effect on the rate of tungsten evaporation are presented. Methods for carrying out an experiment are presented. The experiments are carried out at the 2600 degC tungsten wire temperature and the pressure of oxygen and water vapors (2x10 -3 -5) Pa. Registration of final products of mass transfer is carried out by the DRON-2.0 diffractometer using a detachable substrate. Empirical dependence taking into account oxygen and water vapor effect on the rate of tungsten evaporation is suggested. It is marked that air oxygen and water vapor increase evaporation rate uniformly the difference is observed only in final products of interaction

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

    Science.gov (United States)

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

    2000-07-01

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

  15. Assessing Near-surface Heat, Water Vapor and Carbon Dioxide Exchange Over a Coastal Salt-marsh

    Science.gov (United States)

    Bogoev, I.; O'Halloran, T. L.; LeMoine, J.

    2017-12-01

    Coastal ecosystems play an important role in mitigating the effects of climate change by storing significant quantities of carbon. A growing number of studies suggest that vegetated estuarine habitats, specifically salt marshes, have high long-term rates of carbon sequestration, perhaps even higher than mature tropical and temperate forests. Large amounts of carbon, accumulated over thousands of years, are stored in the plant materials and sediment. Improved understanding of the factors that control energy and carbon exchange is needed to better guide restoration and conservation management practices. To that end, we recently established an observation system to study marsh-atmosphere interactions within the North Inlet-Winyah Bay National Estuarine Research Reserve. Near-surface fluxes of heat, water vapor (H2O) and carbon dioxide (CO2) were measured by an eddy-covariance system consisting of an aerodynamic open-path H2O / CO2 gas analyzer with a spatially integrated 3D sonic anemometer/thermometer (IRGASON). The IRGASON instrument provides co-located and highly synchronized, fast response H2O, CO2 and air- temperature measurements, which eliminates the need for spectral corrections associated with the separation between the sonic anemometer and the gas analyzer. This facilitates calculating the instantaneous CO2 molar mixing ratio relative to dry air. Fluxes computed from CO2 and H2O mixing ratios, which are conserved quantities, do not require post-processing corrections for air-density changes associated with temperature and water vapor fluctuations. These corrections are particularly important for CO2, because they could be even larger than the measured flux. Here we present the normalized frequency spectra of air temperature, water vapor and CO2, as well as their co-spectra with the co-located vertical wind. We also show mean daily cycles of sensible, latent and CO2 fluxes and analyze correlations with air/water temperature, wind speed and light availability.

  16. Monitoring tropospheric water vapor changes using radiosonde data

    International Nuclear Information System (INIS)

    Elliott, W.P.; Smith, M.E.; Angell, J.K.

    1990-01-01

    Significant increases in the water vapor content of the troposphere are expected to accompany temperature increases due to rising concentrations of the greenhouse gases. Thus it is important to follow changes in water vapor over time. There are a number of difficulties in developing a homogeneous data set, however, because of changes in radiosonde instrumentation and reporting practices. The authors report here on preliminary attempts to establish indices of water vapor which can be monitored. The precipitable water between the surface and 500 mb is the first candidate. They describe their method for calculating this quantity from radiosonde data for a network very similar to the network Angell uses for detecting temperature trends. Preliminary results suggest that the noise level is low enough to detect trends in water vapor at the individual stations. While a slight increase in global water vapor is hinted at in the data, and the data suggest there may have been a net transfer of water from the Southern Hemisphere to the Northern Hemisphere, these conclusions are tentative. The authors also discuss the future course of this investigation

  17. Tritium-gas/water-vapor monitor. Tests and evaluation

    International Nuclear Information System (INIS)

    Jalbert, R.A.

    1982-07-01

    A tritium gas/water-vapor monitor was designed and built by the Health Physics Group at the Los Alamos National Laboratory. In its prototype configuration, the monitor took the shape of two separate instruments: a (total) tritium monitor and a water-vapor monitor. Both instruments were tested and evaluated. The tests of the (total) tritium monitor, basically an improved version of the standard flow-through ion-chamber instrument, are briefly reported here and more completely elsewhere. The tests of the water-vapor monitor indicated that the novel approach used to condense water vapor for scintillation counting has a number of serious drawbacks and that further development of the instrument is unwarranted

  18. Water vapor retrieval over many surface types

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Clodius, W.C.; Johnson, J.

    1996-04-01

    In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

  19. Tank vapor characterization project - headspace vapor characterization of Hanford Waste Tank 241-C-107: Second comparison study results from samples collected on 3/26/96

    International Nuclear Information System (INIS)

    Evans, J.C.; Pool, K.H.; Thomas, B.L.

    1997-01-01

    This report describes the analytical results of vapor samples taken from the headspace of waste storage tank 241-C-107 (Tank C-107) at the Hanford Site in Washington State. The results described in this report is the second in a series comparing vapor sampling of the tank headspace using the Vapor Sampling System (VSS) and In Situ Vapor Sampling (ISVS) system without high efficiency particulate air (HEPA) prefiltration. The results include air concentrations of water (H 2 O) and ammonia (NH 3 ), permanent gases, total non-methane organic compounds (TO-12), and individual organic analytes collected in SUMMA trademark canisters and on triple sorbent traps (TSTs). Samples were collected by Westinghouse Hanford Company (WHC) and analyzed by Pacific Northwest National Laboratory (PNNL). Analyses were performed by the Vapor Analytical Laboratory (VAL) at PNNL. Analyte concentrations were based on analytical results and, where appropriate, sample volume measurements provided by WHC

  20. Tank vapor characterization project. Headspace vapor characterization of Hanford waste tank 241-BY-108: Second comparison study results from samples collected on 3/28/96

    International Nuclear Information System (INIS)

    Thomas, B.L.; Pool, K.H.; Evans, J.C.

    1997-01-01

    This report describes the analytical results of vapor samples taken from the headspace of waste storage tank 241-BY-108 (Tank BY-108) at the Hanford Site in Washington State. The results described in this report is the second in a series comparing vapor sampling of the tank headspace using the Vapor Sampling System (VSS) and In Situ Vapor Sampling (ISVS) system without high efficiency particulate air (HEPA) prefiltration. The results include air concentrations of water (H 2 O) and ammonia (NH 3 ), permanent gases, total non-methane organic compounds (TO-12), and individual organic analytes collected in SUMMA trademark canisters and on triple sorbent traps (TSTs). Samples were collected by Westinghouse Hanford Company (WHC) and analyzed by Pacific Northwest National Laboratory (PNNL). Analyses were performed by the Vapor Analytical Laboratory (VAL) at PNNL. Analyte concentrations were based on analytical results and, where appropriate, sample volume measurements provided by WHC

  1. Reduced water vapor transmission rates of low-temperature solution-processed metal oxide barrier films via ultraviolet annealing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seonuk; Jeong, Yong Jin; Baek, Yonghwa; Kim, Lae Ho; Jang, Jin Hyuk; Kim, Yebyeol [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); An, Tae Kyu [Department of Polymer Science & Engineering, Korea National University of Transportation, 50 Daehak-Ro, Chungju (Korea, Republic of); Nam, Sooji, E-mail: sjnam15@etri.re.kr [Information Control Device Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700 (Korea, Republic of); Kim, Se Hyun, E-mail: shkim97@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, North Gyeongsang 712-749 (Korea, Republic of); Jang, Jaeyoung, E-mail: jyjang15@hanyang.ac.kr [Department of Energy Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Chan Eon, E-mail: cep@postech.ac.kr [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2017-08-31

    Highlights: • Sol-gel-derived aluminum oxide thin films were prepared using ultraviolet (UV) annealing. • UV irradiation dramatically promoted the densification of AlO{sub x} during the annealing stage, thereby forming a close-packed AlO{sub x} film. • The resulting AlO{sub x} films deposited on polymer substrates exhibited good water vapor blocking properties with low water vapor transmission rates (WVTRs). - Abstract: Here, we report the fabrication of low-temperature sol-gel-derived aluminum oxide (AlO{sub x}) films via ultraviolet (UV) annealing and the investigation of their water vapor blocking properties by measuring the water vapor transmission rates (WVTRs). The UV annealing process induced the formation of a dense metal-oxygen-metal bond (Al-O-Al structure) at low temperatures (<200 °C) that are compatible with commercial plastic substrates. The density of the UV-annealed AlO{sub x} thin film at 180 °C was comparable to that of AlO{sub x} thin films that have been thermally annealed at 350 °C. Furthermore, the UV-annealed AlO{sub x} thin films exhibited a high optical transparency in the visible region (>99%) and good electrical insulating properties (∼10{sup −7} A/cm{sup 2} at 2 MV/cm). Finally, we confirmed that a dense AlO{sub x} thin film was successfully deposited onto the plastic substrate via UV annealing at low temperatures, leading to a substantial reduction in the WVTRs. The Ca corrosion test was used to measure the WVTRs of AlO{sub x} thin films deposited onto polyethylene naphthalate or polyimide substrates, determined to be 0.0095 g m{sup −2} day{sup −1} (25 °C, 50% relative humidity) and 0.26 g m{sup −2} day{sup −1}, respectively.

  2. Water-Vapor Raman Lidar System Reaches Higher Altitude

    Science.gov (United States)

    Leblanc, Thierry; McDermid, I. Stewart

    2010-01-01

    A Raman lidar system for measuring the vertical distribution of water vapor in the atmosphere is located at the Table Mountain Facility (TMF) in California. Raman lidar systems for obtaining vertical water-vapor profiles in the troposphere have been in use for some time. The TMF system incorporates a number of improvements over prior such systems that enable extension of the altitude range of measurements through the tropopause into the lower stratosphere. One major obstacle to extension of the altitude range is the fact that the mixing ratio of water vapor in the tropopause and the lower stratosphere is so low that Raman lidar measurements in this region are limited by noise. Therefore, the design of the TMF system incorporates several features intended to maximize the signal-to-noise ratio. These features include (1) the use of 355-nm-wavelength laser pulses having an energy (0.9 J per pulse) that is high relative to the laser-pulse energy levels of prior such systems, (2) a telescope having a large aperture (91 cm in diameter) and a narrow field of view (angular width .0.6 mrad), and (3) narrow-bandpass (wavelength bandwidth 0.6 nm) filters for the water-vapor Raman spectral channels. In addition to the large-aperture telescope, three telescopes having apertures 7.5 cm in diameter are used to collect returns from low altitudes.

  3. Water vapor movement in freezing aggregate base materials.

    Science.gov (United States)

    2014-06-01

    The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

  4. Simultaneous desulfurization and denitrification of flue gas by ·OH radicals produced from O2+ and water vapor in a duct.

    Science.gov (United States)

    Bai, Mindi; Zhang, Zhitao; Bai, Mindong

    2012-09-18

    In the present study, simultaneous flue gas desulfurization and denitrification are achieved with ·OH radicals generated from O(2)(+) reacting with water vapor in a duct. The O(2)(+) ions are generated by a strong ionization dielectric barrier discharge and then injected into the duct. Compared with conventional gas discharge treatment, the present method does not need a plasma reaction reactor, additional catalysts, reductants, or oxidants. The main recovered products are the liquids H(2)SO(4) and HNO(3), which can be used in many processes. Removal rates of 97% for NO and 82% for SO(2) are obtained under the following optimal experimental conditions: molar ratio of reactive oxygen species (O(2)(+), O(3)) to SO(2) and NO, 5; inlet flue gas temperature, 65 °C; reaction time, 0.94 s; and H(2)O volume fraction, 8%. Production of O(2)(+) and the plasma reaction mechanisms are discussed, and the recovered acid is characterized. The experimental results show that the present method performs better for denitrification than for desulfurization. Compared with conventional air discharge flue gas treatments, the present method has lower initial investment and operating costs, and the equipment is more compact.

  5. A tentative detection of the 183-GHz water vapor line in the martian atmosphere: Constraints upon the H2O abundance and vertical distribution

    Science.gov (United States)

    Encrenaz, TH.; Lellouch, E.; Cernicharo, J.; Paubert, G.; Gulkis, S.

    1995-01-01

    The 183-GHz water vapor line was tentatively detected on Mars in January 1991, with the IRAM 30-m millimeter antenna, under extremely dry atmospheric conditions. The measurement refers to the whole disk. The spectral line, although marginally detected, can be fit with a constant H2O mixing ratio of 1.0 x 10(exp -5), which corresponds to a water abundance of 1 pr-microns; in any case, an upper limit of 3 pr-microns is inferred. This value is comparable to the very small abundances measured by Clancy (1992) 5 weeks before our observation and seems to imply both seasonal and long-term variations in the martian water cycle.

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

    Science.gov (United States)

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

    2011-09-01

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

  7. Chemical and morphological modifications of single layer graphene submitted to annealing in water vapor

    Science.gov (United States)

    Rolim, Guilherme Koszeniewski; Corrêa, Silma Alberton; Galves, Lauren Aranha; Lopes, João Marcelo J.; Soares, Gabriel Vieira; Radtke, Cláudio

    2018-01-01

    Modifications of single layer graphene transferred to SiO2/Si substrates resulting from annealing in water vapor were investigated. Near edge X-ray absorption fine structure spectroscopy evidenced graphene puckering between 400 and 500 °C. Synchrotron radiation based X-ray photoelectron spectroscopy showed variation of sp2 and sp3C bonding configurations specially in this same temperature range. Moreover, oxygen related functionalities are formed as a result of water vapor annealing. Based on these results and complementary Raman and nuclear reaction analysis, one distinguishes three different regimes of water interaction with graphene concerning modifications of the graphene layer. In the low temperature range (200-400 °C), no prominent modification of graphene itself is observed. At higher temperatures (400-500 °C), to accommodate newly formed oxygen functionalities, the flat and continuous sp2 bonding network of graphene is disrupted, giving rise to a puckered layer. For 600 °C and above, shrinking of graphene domains and a higher doping level take place.

  8. Heteroepitaxial growth of Ba1 - xSrxTiO3/YBa2Cu3O7 - x by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Chern, C. S.; Liang, S.; Shi, Z. Q.; Yoon, S.; Safari, A.; Lu, P.; Kear, B. H.; Goodreau, B. H.; Marks, T. J.; Hou, S. Y.

    1994-06-01

    Epitaxial Ba1-xSrxTiO3(BST)/YBa2Cu3O7-x heterostructures with superior electrical and dielectric properties have been fabricated by plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD). Data of x-ray diffraction and high resolution transmission electron microscopy showed that oriented Ba1-xSrxTiO3 layers were epitaxially deposited on epitaxial (001) YBa2Cu3O7-x layers. The leakage current density through the Ba1-xSrxTiO3 films was about 10-7 A/cm2 at 2 V (about 2×105 V/cm) operation. Moreover, the results of capacitance-temperature measurements showed that the PE-MOCVD Ba1-xSrxTiO3 films had Curie temperatures of about 30 °C and a peak dielectric constant of 600 at zero bias voltage. The Rutherford backscattering spectrometry and x-ray diffraction results showed that the BST film composition was controlled between Ba0.75Sr0.25TiO3 and Ba0.8Sr0.2TiO3. The structural and electrical properties of the Ba1-xSrxTiO3/YBa2Cu3O7-x heterostructure indicated that conductive oxide materials with close lattice to Ba1-xSrxTiO3 can be good candidates for the bottom electrode.

  9. Millimeter-wave Radiometer for High Sensitivity Water Vapor Profiling in Arid Regions

    Energy Technology Data Exchange (ETDEWEB)

    Pazmany, Andrew

    2006-11-09

    Abstract - ProSensing Inc. has developed a G-band (183 GHz) water Vapor Radiometer (GVR) for long-term, unattended measurements of low concentrations of atmospheric water vapor and liquid water. Precipitable water vapor and liquid water path are estimated from zenith brightness temperatures measured from four double-sideband receiver channels, centered at 183.31 1, 3 and 7, and 14 GHz. A prototype ground-based version of the instrument was deployed at the DOE ARM program?s North Slope of Alaska site near Barrow AK in April 2005, where it collected data continuously for one year. A compact, airborne version of this instrument, packaged to operate from a standard 2-D PMS probe canister, has been tested on the ground and is scheduled for test flights in the summer of 2006. This paper presents design details, laboratory test results and examples of retrieved precipitable water vapor and liquid water path from measured brightness temperature data.

  10. Low-energy proton stopping power of N2, O2, and water vapor, and deviations from Bragg's rule

    International Nuclear Information System (INIS)

    Xu, Y.J.; Khandelwal, G.S.; Wilson, J.W.

    1984-01-01

    A modified local-plasma model, based on the works of Lindhard and Winther, and Bethe, Brown, and Walske is established. The Gordon-Kim model for molecular-electron density is used to calculate stopping power of N 2 , O 2 , and water vapor for protons of energy ranging from 40 keV to 2.5 MeV, resulting in good agreement with experimental data. Deviations from Bragg's rule are evaluated and are discussed under the present theoretical model

  11. Remote measurement of high preeruptive water vapor emissions at Sabancaya volcano by passive differential optical absorption spectroscopy

    Science.gov (United States)

    Kern, Christoph; Masias, Pablo; Apaza, Fredy; Reath, Kevin; Platt, Ulrich

    2017-01-01

    Water (H2O) is by far the most abundant volcanic volatile species and plays a predominant role in driving volcanic eruptions. However, numerous difficulties associated with making accurate measurements of water vapor in volcanic plumes have limited their use as a diagnostic tool. Here we present the first detection of water vapor in a volcanic plume using passive visible-light differential optical absorption spectroscopy (DOAS). Ultraviolet and visible-light DOAS measurements were made on 21 May 2016 at Sabancaya Volcano, Peru. We find that Sabancaya's plume contained an exceptionally high relative water vapor abundance 6 months prior to its November 2016 eruption. Our measurements yielded average sulfur dioxide (SO2) emission rates of 800–900 t/d, H2O emission rates of around 250,000 t/d, and an H2O/SO2 molecular ratio of 1000 which is about an order of magnitude larger than typically found in high-temperature volcanic gases. We attribute the high water vapor emissions to a boiling-off of Sabancaya's hydrothermal system caused by intrusion of magma to shallow depths. This hypothesis is supported by a significant increase in the thermal output of the volcanic edifice detected in infrared satellite imagery leading up to and after our measurements. Though the measurement conditions encountered at Sabancaya were very favorable for our experiment, we show that visible-light DOAS systems could be used to measure water vapor emissions at numerous other high-elevation volcanoes. Such measurements would provide observatories with additional information particularly useful for forecasting eruptions at volcanoes harboring significant hydrothermal systems.

  12. The Oxidation Rate of SiC in High Pressure Water Vapor Environments

    Science.gov (United States)

    Opila, Elizabeth J.; Robinson, R. Craig

    1999-01-01

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

  13. Low-Temperature Preparation of (111)-oriented Pb(Zr,Ti)O3 Films Using Lattice-Matched (111)SrRuO3/Pt Bottom Electrode by Metal-Organic Chemical Vapor Deposition

    Science.gov (United States)

    Kuwabara, Hiroki; Sumi, Akihiro; Okamoto, Shoji; Hoko, Hiromasa; Cross, Jeffrey S.; Funakubo, Hiroshi

    2009-04-01

    Pb(Zr0.35Ti0.65)O3 (PZT) films 170 nm thick were prepared at 415 °C by pulsed metal-organic chemical vapor deposition. The (111)-oriented PZT films with local epitaxial growth were obtained on (111)SrRuO3/(111)Pt/TiO2/SiO2/Si substrates and their ferroelectricities were ascertained. Ferroelectricity was improved by postannealing under O2 gas flow up to 550 °C. Larger remanent polarization and better fatigue endurance were obtained using a SrRuO3 top electrode compared to a Pt top electrode for PZT films after annealing at 500 °C.

  14. Eddy transport of water vapor in the Martian atmosphere

    Science.gov (United States)

    Murphy, J. R.; Haberle, Robert M.

    1993-01-01

    Viking orbiter measurements of the Martian atmosphere suggest that the residual north polar water-ice cap is the primary source of atmospheric water vapor, which appears at successively lower northern latitudes as the summer season progresses. Zonally symmetric studies of water vapor transport indicate that the zonal mean meridional circulation is incapable of transporting from north polar regions to low latitudes the quantity of water vapor observed. This result has been interpreted as implying the presence of nonpolar sources of water. Another possibility is the ability of atmospheric wave motions, which are not accounted for in a zonally symmetric framework, to efficiently accomplish the transport from a north polar source to the entirety of the Northern Hemisphere. The ability or inability of the full range of atmospheric motions to accomplish this transport has important implications regarding the questions of water sources and sinks on Mars: if the full spectrum of atmospheric motions proves to be incapable of accomplishing the transport, it strengthens arguments in favor of additional water sources. Preliminary results from a three dimensional atmospheric dynamical/water vapor transport numerical model are presented. The model accounts for the physics of a subliming water-ice cap, but does not yet incorporate recondensation of this sublimed water. Transport of vapor away from this water-ice cap in this three dimensional framework is compared with previously obtained zonally symmetric (two dimensional) results to quantify effects of water vapor transport by atmospheric eddies.

  15. Reactions of modulated molecular beams with pyrolytic graphite IV. Water vapor

    International Nuclear Information System (INIS)

    Olander, D.R.; Acharya, T.R.; Ullman, A.Z.

    1977-01-01

    The reaction of water vapor with the prism plane face of anneal pyrolytic graphite was investigated by modulated molecular beam--mass spectrometry methods. The equivalent water vapor pressure of the beam was approx.2 x 10 -5 Torr and the graphite temperature was varied from 300 to 2500 0 K. The mechanism was deduced from three types of experiments: isotope exchange utilizing modulated H 2 O and steady D 2 O beams; measurements of the phase difference between H 2 O and neon reflected from the surface from a mixed primary beam of these species; and reaction of a modulated H 2 O beam to produce CO and H 2 . Based upon the isotope exchange experiments chemisorption of water on graphite was found to be dissociative and reversible. Incident water molecules chemisorbed with a sticking probability of 0.15 +- 0.02 to form the complexes C--OH and C--H. Recombination of the surface complexes reverses the adsorption step and is responsible for the isotope exchange properties of the graphite surface. This process is unactivated. Reaction to produce CO and H 2 also results from collisions of the primary surface complexes, but this step has an activation energy of 170 kJ/mole. This reaction yields bound complexes tentatively identified as C--O and H--C--H, which then decompose to produce the stable reaction products. All of the above steps exhibit characteristic times on the order of milliseconds, and are therefore detectable by the modulated beam method. All surface intermediates are strongly affected by solution and diffusion in the bulk of the solid

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

    Science.gov (United States)

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

    1991-01-01

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

  17. Growth mechanism and elemental distribution of beta-Ga2O3 crystalline nanowires synthesized by cobalt-assisted chemical vapor deposition.

    Science.gov (United States)

    Wang, Hui; Lan, Yucheng; Zhang, Jiaming; Crimp, Martin A; Ren, Zhifeng

    2012-04-01

    Long beta-Ga2O3 crystalline nanowires are synthesized on patterned silicon substrates using chemical vapor deposition technique. Advanced electron microscopy indicates that the as-grown beta-Ga2O3 nanowires are consisted of poly-crystalline (Co, Ga)O tips and straight crystalline beta-Ga2O3 stems. The catalytic cobalt not only locates at the nanowire tips but diffuses into beta-Ga2O3 nanowire stems several ten nanometers. A solid diffusion growth mechanism is proposed based on the spatial elemental distribution along the beta-Ga2O3 nanowires at nanoscale.

  18. Water vapor estimation using digital terrestrial broadcasting waves

    Science.gov (United States)

    Kawamura, S.; Ohta, H.; Hanado, H.; Yamamoto, M. K.; Shiga, N.; Kido, K.; Yasuda, S.; Goto, T.; Ichikawa, R.; Amagai, J.; Imamura, K.; Fujieda, M.; Iwai, H.; Sugitani, S.; Iguchi, T.

    2017-03-01

    A method of estimating water vapor (propagation delay due to water vapor) using digital terrestrial broadcasting waves is proposed. Our target is to improve the accuracy of numerical weather forecast for severe weather phenomena such as localized heavy rainstorms in urban areas through data assimilation. In this method, we estimate water vapor near a ground surface from the propagation delay of digital terrestrial broadcasting waves. A real-time delay measurement system with a software-defined radio technique is developed and tested. The data obtained using digital terrestrial broadcasting waves show good agreement with those obtained by ground-based meteorological observation. The main features of this observation are, no need for transmitters (receiving only), applicable wherever digital terrestrial broadcasting is available and its high time resolution. This study shows a possibility to estimate water vapor using digital terrestrial broadcasting waves. In the future, we will investigate the impact of these data toward numerical weather forecast through data assimilation. Developing a system that monitors water vapor near the ground surface with time and space resolutions of 30 s and several kilometers would improve the accuracy of the numerical weather forecast of localized severe weather phenomena.

  19. Trace water vapor determination in nitrogen and corrosive gases using infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza, L.H.; Niemczyk, T.M. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemistry; Stallard, B.R.; Garcia, M.J. [Sandia National Labs., Albuquerque, NM (United States)

    1997-06-01

    The generation of particles in gas handling systems as a result of corrosion is a major concern in the microelectronics industry. The corrosion can be caused by the presence of trace quantities of water in corrosive gases such as HCl or HBr. FTIR spectroscopy has been shown to be a method that can be made compatible with corrosive gases and is capable of detecting low ppb levels of water vapor. In this report, the application of FTIR spectroscopy combined with classical least squares multivariate calibration to detect trace H{sub 2}O in N{sub 2}, HCl and HBr is discussed. Chapter 2 discusses the gas handling system and instrumentation required to handle corrosive gases. A method of generating a background spectrum useful to the measurements discussed in this report, as well as in other application areas such as gas phase environmental monitoring, is discussed in Chapter 3. Experimental results obtained with the first system are presented in Chapter 4. Those results made it possible to optimize the design options for the construction of a dedicate system for low ppb water vapor determination. These designs options are discussed in Chapter 5. An FTIR prototype accessory was built. In addition, a commercially available evacuable FTIR system was obtained for evaluation. Test results obtained with both systems are discussed in Chapter 6. Experiments dealing with the interaction between H{sub 2}O-HCl and potential improvements to the detection system are discussed in Chapter 7.

  20. Component activities in the system thorium nitrate-nitric acid-water at 25oC

    International Nuclear Information System (INIS)

    Lemire, R.J.; Brown, C.P.

    1982-01-01

    The equilibrium composition of the vapor above thorium nitrate-nitric acid-water mixtures has been studied as a function of the concentrations of thorium nitrate and nitric acid using a transpiration technique. At 25 o C, the thorium nitrate concentrations m T ranged from 0.1 to 2.5 molal and the nitric acid concentrations m N from 0.3 to 25 molal. The vapor pressure of the nitric acid was found to increase with increasing thorium nitrate concentration for a constant molality of nitric acid in aqueous solution. At constant m T , the nitric acid vapor pressure was particularly enhanced at low nitric acid concentrations. The water vapor pressures decreased regularly with increasing concentrations of both nitric acid and thorium nitrate. The experimental data were fitted to Scatchard's ion-component model, and to empirical multiparameter functions. From the fitting parameters, and available literature data for the nitric acid-water and thorium nitrate-water systems at 25 o C, expressions were calculated for the variation of water and thorium nitrate activities, as functions of the nitric acid and thorium nitrate concentrations, using the Gibbs-Duhem equation. Calculated values for the thorium nitrate activities were strongly dependent on the form of the function originally used to fit the vapor pressure data. (author)

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

    Science.gov (United States)

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

    2018-03-01

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

  2. A visual water vapor photonic crystal sensor with PVA/SiO2 opal structure

    Science.gov (United States)

    Yang, Haowei; Pan, Lei; Han, Yingping; Ma, Lihua; Li, Yao; Xu, Hongbo; Zhao, Jiupeng

    2017-11-01

    In study, we proposed a simple yet fast optical sensing motif based on thimbleful of polyvinyl alcohol (PVA) infiltrated photonic crystal (PC), which allows for high efficiency in vapor sensing through changes in their inter-layer space. Linear response to a broad dynamic range of vapor concentration was realized. Ultrafast response time (<1 s) and excellent recyclability were also demonstrated. Selective response to a vapor was exhibited, reflecting well the characteristic sorption properties of PVA, with which colorimetric reporting was readily achieved. These substantial improvements in performance are attributed to the efficacy of signal transduction and the enhanced signal transduction because of thimbleful PVA infiltrated space between adjacent SiO2 nanospheres.

  3. Diameter Tuning of β-Ga2O3 Nanowires Using Chemical Vapor Deposition Technique.

    Science.gov (United States)

    Kumar, Mukesh; Kumar, Vikram; Singh, R

    2017-12-01

    Diameter tuning of [Formula: see text]-Ga 2 O 3 nanowires using chemical vapor deposition technique have been investigated under various experimental conditions. Diameter of root grown [Formula: see text]-Ga 2 O 3 nanowires having monoclinic crystal structure is tuned by varying separation distance between metal source and substrate. Effect of gas flow rate and mixer ratio on the morphology and diameter of nanowires has been studied. Nanowire diameter depends on growth temperature, and it is independent of catalyst nanoparticle size at higher growth temperature (850-900 °C) as compared to lower growth temperature (800 °C). These nanowires show changes in structural strain value with change in diameter. Band-gap of nanowires increases with decrease in the diameter.

  4. Effect of sweep gas chemistry on vaporization of Li4SiO4

    International Nuclear Information System (INIS)

    Yamawaki, M.; Yamaguchi, K.

    1995-01-01

    Gas/solid equilibria in the system Li 4 SiO 4 -D 2 -D 2 O were studied by means of Knudsen effusion mass spectrometry. A Knudsen effusion mass spectrometer was modified to enable studies of reactions of hydrogen and/or water vapor with ceramic breeder materials. A gas inlet system was constructed to allow the introduction of gases into a platinum Knudsen cell, from which the equilibrated gaseous reaction products effuse. From the experimental results, it has been deduced that the equilibrium constants of vaporization reactions differ correspondingly to the nonstoichiometry of lithium orthosilicate. ((orig.))

  5. Nonstoichiometry and stability in water of undoped SrCeO3

    Directory of Open Access Journals (Sweden)

    Jurado, J. R.

    2003-10-01

    Full Text Available Strontium cerate is the parent phase of an important class of proton-conducting perovskites with various potential technological applications. Phase formation and structure of SrCeO3 with Sr:Ce nonstoichiometry have been investigated for the series, Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Analyses by EPMA (electron probe micro analysis and X-ray diffraction (XRD indicate that, for samples sintered at 1350°C, the main phase is Sr-rich for all x. The accommodation of excess SrO in the bulk phase and/or intergranular regions is discussed. The stability of nominally stoichiometric SrCeO3 was examined in an atmosphere of high water vapour partial pressure (pH2O for 2 hours, degrading to Sr(OH2.H2O and CeO2 for pH2O3.6atm.La fase SrCeO3 da origen a una importante familia de perovskitas conductoras protónicas con potenciales aplicaciones tecnológicas. En este trabajo se estudia la formación de la fase y la estructura de SrCeO3 con la relación Sr:Ce no estequiométrica para la serie Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Los análisis por microsonda (EPMA y difracción de rayos X (DRX indican que en las muestras sinterizadas a 1350°C, la fase principal es rica en estroncio para todo valor de x. Se discute la posible ubicación del exceso de SrO tanto en la región intergranular como en el propio grano. También se examina la estabilidad de la composición con estequiometría nominal SrCeO3 en una atmosfera con una alta presión de vapor de agua (pH2O, observándose que la degradación a Sr(OH2.H2O y CeO2 ocurre a pH2O3.6atm (expuesto durante 2 horas.

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

    Science.gov (United States)

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

    1974-01-01

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

  7. Water vapor permeation and dehumidification performance of poly(vinyl alcohol)/lithium chloride composite membranes

    KAUST Repository

    Bui, Duc Thuan

    2015-10-09

    Thin and robust composite membranes comprising stainless steel scaffold, fine and porous TiO2 and polyvinyl alcohol/lithium chloride were fabricated and studied for air dehumidification application. Higher hydrophilicity, sorption and permeation were observed for membranes with increased lithium chloride content up to 50%. The permeation and sorption properties of the membranes were investigated under different temperatures. The results provided a deeper insight into the membrane water vapor permeation process. It was specifically noted that lithium chloride significantly reduces water diffusion energy barrier, resulting in the change of permeation energy from positive to negative values. Higher water vapor permeance was observed for the membrane with higher LiCl content at lower temperature. The isothermal air dehumidification tests show that the membrane is suitable for dehumidifying air in high humid condition. Additionally, results also indicate a trade-off between the humidity ratio drop with the water vapor removal rate when varying air flowrate.

  8. Correlations between water-soluble organic aerosol and water vapor: a synergistic effect from biogenic emissions?

    Science.gov (United States)

    Hennigan, Christopher J; Bergin, Michael H; Weber, Rodney J

    2008-12-15

    Ground-based measurements of meteorological parameters and water-soluble organic carbon in the gas(WSOCg) and particle (WSOCp) phases were carried out in Atlanta, Georgia, from May to September 2007. Fourteen separate events were observed throughout the summer in which WSOCp and water vapor concentrations were highly correlated (average WSOCp-water vapor r = 0.92); however, for the entire summer, no well-defined relationship existed between the two. The correlation events, which lasted on average 19 h, were characterized by a wide range of WSOCp and water vapor concentrations. Several hypotheses for the correlation are explored, including heterogeneous liquid phase SOA formation and the co-emission of biogenic VOCs and water vapor. The data provide supporting evidence for contributions from both and suggest the possibility of a synergistic effect between the co-emission of water vapor and VOCs from biogenic sources on SOA formation. Median WSOCp concentrations were also correlated with elemental carbon (EC), although this correlation extended over the entire summer. Despite the emission of water vapor from anthropogenic mobile sources and the WSOCp-EC correlation, mobile sources were not considered a potential cause for the WSOCp-water vapor correlations because of their low contribution to the water vapor budget. Meteorology could perhaps have influenced the WSOCp-EC correlation, but other factors are implicated as well. Overall, the results suggest that the temperature-dependent co-emission of water vapor through evapotranspiration and SOA precursor-VOCs by vegetation may be an important process contributing to SOA in some environments.

  9. Synthesis of metallic ReO3 nanowires

    International Nuclear Information System (INIS)

    Myung, Dongshin; Lee, Yumin; Lee, Jaeyeon; Kim, Myung Hwa; Yu, Hak Ki; Lee, Jong-Lam; Baik, Jeong Min; Kim, Woong

    2010-01-01

    We present the synthesis of highly crystalline metallic rhenium trioxide (ReO 3 ) nanowires via a simple physical vapor transport at 300 C for the first time. Based on HRTEM, the ReO 3 nanowires exhibit a core of perfect cubic perovskite-type single crystal structure with a shell of thin amorphous and disordered structures of less than 2 nm in the near surface layers. Possibly this is due to proton intercalation induced by the surface reaction of single crystal ReO 3 with water. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. H2SO4-HNO3-H2O ternary system in the stratosphere

    Science.gov (United States)

    Kiang, C. S.; Hamill, P.

    1974-01-01

    Estimation of the equilibrium vapor pressure over the ternary system H2SO4-HNO3-H2O to study the possibility of stratospheric aerosol formation involving HNO3. It is shown that the vapor pressures for the ternary system H2SO4-HNO3-H2O with weight composition around 70-80% H2SO4, 10-20% HNO3, 10-20% H2O at -50 C are below the order of 10 to the minus 8th mm Hg. It is concluded that there exists more than sufficient nitric acid and water vapor in the stratosphere to participate in ternary system aerosol formation at -50 C. Therefore, HNO3 should be present in stratospheric aerosols, provided that H2SO4 is also present.

  11. Investigation of SiO{sub 2} film growth on 4H-SiC by direct thermal oxidation and postoxidation annealing techniques in HNO{sub 3} and H{sub 2}O vapor at varied process durations

    Energy Technology Data Exchange (ETDEWEB)

    Poobalan, Banu [Electronic Materials Research Group, School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Seberang Perai Selatan, Penang (Malaysia); Moon, Jeong Hyun; Kim, Sang-Cheol; Joo, Sung-Jae; Bahng, Wook; Kang, In Ho; Kim, Nam-Kyun [Power Semiconductor Research Centre, Korea Electrotechnology Research Institute, PO Box 20, Changwon, Gyungnam 641120 (Korea, Republic of); Cheong, Kuan Yew, E-mail: cheong@eng.usm.my [Electronic Materials Research Group, School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Seberang Perai Selatan, Penang (Malaysia)

    2014-11-03

    This study has revealed that HNO{sub 3} and H{sub 2}O vapors can be utilized as direct thermal oxidation or postoxidation annealing agents at a temperature above 1000 °C; as they play a major role in simultaneous oxidation/nitridation/hydrogenation processes at the bulk oxide and SiO{sub 2}/SiC interface. The varied process durations of the above-mentioned techniques contribute to the development of thicker gate oxides for high power device applications with improved electrical properties, lower interface-state density and higher breakdown voltage as compared to oxides grown through a more conventional wet (H{sub 2}O vapor only) oxidation technique. The study highlights the effects of hydrogen and nitrogen species on the passivation of structural defects at the bulk oxide and the SiO{sub 2}/SiC interface, which are revealed through the use of Time-of-Flight Secondary Ion Mass Spectroscopy and X-ray Photoelectron Spectroscopy. The physical properties of the substrate after oxide removal show that the surface roughness decreases as the process durations increase with longer hours of H{sub 2}O and HNO{sub 3} vapor exposures on the samples, which is mainly due to the significant reduction of carbon content at the SiO{sub 2}/SiC interface. - Highlights: • Direct thermal oxidation and postoxidation annealing techniques in HNO{sub 3}/H{sub 2}O vapor • SiO{sub 2} film growth in H{sub 2}O/HNO{sub 3}vapor at varied process durations • Thicker SiO{sub 2} film growth via annealing than direct growth in HNO{sub 3}/H{sub 2}O vapor • Nitrogen and hydrogen as passivation elements in SiO{sub 2}/SiC interface and SiO{sub 2} bulk • Significant reduction of carbon and Si-dangling bonds at the SiC/SiO{sub 2} interface.

  12. Space-Time Variations in Water Vapor as Observed by the UARS Microwave Limb Sounder

    Science.gov (United States)

    Elson, Lee S.; Read, William G.; Waters, Joe W.; Mote, Philip W.; Kinnersley, Jonathan S.; Harwood, Robert S.

    1996-01-01

    Water vapor in the upper troposphere has a significant impact on the climate system. Difficulties in making accurate global measurements have led to uncertainty in understanding water vapor's coupling to the hydrologic cycle in the lower troposphere and its role in radiative energy balance. The Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite is able to retrieve water vapor concentration in the upper troposphere with good sensitivity and nearly global coverage. An analysis of these preliminary retrievals based on 3 years of observations shows the water vapor distribution to be similar to that measured by other techniques and to model results. The primary MLS water vapor measurements were made in the stratosphere, where this species acts as a conserved tracer under certain conditions. As is the case for the upper troposphere, most of the stratospheric discussion focuses on the time evolution of the zonal mean and zonally varying water vapor. Stratospheric results span a 19-month period and tropospheric results a 36-month period, both beginning in October of 1991. Comparisons with stratospheric model calculations show general agreement, with some differences in the amplitude and phase of long-term variations. At certain times and places, the evolution of water vapor distributions in the lower stratosphere suggests the presence of meridional transport.

  13. A FGGE water vapor wind data set

    Science.gov (United States)

    Stewart, Tod R.; Hayden, Christopher M.

    1985-01-01

    It has been recognized for some time that water vapor structure visible in infrared imagery offers a potential for obtaining motion vectors when several images are considered in sequence (Fischer et al., 1981). A study evaluating water vapor winds obtained from the VISSR atmospheric sounder (Stewart et al., 1985) has confirmed the viability of the approach. More recently, 20 data sets have been produced from METEOSAT water vapor imagery for the FGGE period of 10-25 November 1979. Where possible, two data sets were prepared for each day at 0000 and 1200 GMT and compared with rawinsondes over Europe, Africa, and aircraft observations over the oceans. Procedures for obtaining winds were, in general, similar to the earlier study. Motions were detected both by a single pixel tracking and a cross correlation method by using three images individually separated by one hour. A height assignment was determined by matching the measured brightness temperature to the temperature structure represented by the FGGE-IIIB analyses. Results show that the METEOSAT water vapor winds provide uniform horizontal coverage of mid-level flow over the globe with good accuracy.

  14. Uranium/water vapor reactions in gaseous atmospheres

    International Nuclear Information System (INIS)

    Jackson, R.L.; Condon, J.B.; Steckel, L.M.

    1977-07-01

    Experiments have been performed to determine the effect of varying humidities, gaseous atmospheres, and temperatures on the uranium/water vapor reaction. A balance, which allowed continuous in-system weighings, was used to determine the rates of the uranium/water vapor reactions at water vapor pressures of 383, 1586, and 2853 Pa and at temperatures of 80, 100, and 150 0 C in atmospheres of hydrogen, argon, or argon/oxygen mixtures. Based on rate data, the reactions were characterized as hydriding or nonhydriding. Hydriding reactions were found to be preferred in moist hydrogen systems at the higher temperatures and the lower humidities. The presence of hydrogen in hydriding systems was found to initially inhibit the reaction, but causes an acceleration of the rate in the final stages. In general, reaction rates of hydriding systems approached the hydriding rates calculated and observed in dry hydrogen. Hydriding and nonhydriding reaction rates showed a positive correlation to temperature and water vapor pressure. Final reaction rates in moist argon/oxygen mixtures of 1.93, 4.57, and 9.08 mole percent oxygen were greater than the rates observed in moist hydrogen or argon. Final reaction rates were negatively correlated to the oxygen concentration

  15. Detection of water vapor on Jupiter

    Science.gov (United States)

    Larson, H. P.; Fink, U.; Treffers, R.; Gautier, T. N., III

    1975-01-01

    High-altitude (12.4 km) spectroscopic observations of Jupiter at 5 microns from the NASA 91.5 cm airborne infrared telescope have revealed 14 absorptions assigned to the rotation-vibration spectrum of water vapor. Preliminary analysis indicates a mixing ratio about 1 millionth for the vapor phase of water. Estimates of temperature (greater than about 300 K) and pressure (less than 20 atm) suggest observation of water deep in Jupiter's hot spots responsible for its 5 micron flux. Model-atmosphere calculations based on radiative-transfer theory may change these initial estimates and provide a better physical picture of Jupiter's atmosphere below the visible cloud tops.

  16. Effect of Water Vapor on High-Temperature Corrosion under Conditions Mimicking Biomass Firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    The variable flue gas composition in biomass-fired plants, among other parameters, contributes to the complexityof high-temperature corrosion of materials. Systematic parameter studies are thus necessary to understand the underlyingcorrosion mechanisms. This paper investigates the effect of water...... (H2O) vapor content in the flue gas on the high-temperaturecorrosion of austenitic stainless steel (TP 347H FG) under laboratory conditions, to improve the understanding of corrosionmechanisms. Deposit-coated and deposit-free samples were isothermally exposed for 72 h in a synthetic flue gas...... previouslyreported findings suggest that an increase in the water vapor content will cause competitive adsorption on active sites....

  17. SnO2 thin film synthesis for organic vapors sensing at ambient temperature

    Directory of Open Access Journals (Sweden)

    N.H. Touidjen

    2016-12-01

    Full Text Available The present work is a study of tin dioxide (SnO2 based thin sensitive layer dedicated to organic vapors detection at ambient temperature. SnO2 thin film was deposited by chemical spray pyrolysis technique. The glass substrate temperature was kept to 400 °C, using a starting solution of 0.1 M tin (II dichloride dihydrate (SnCl2, 2H2O. Films structural and morphological properties were characterized using X-ray diffraction (XRD, scanning electron microscopy (SEM and atomic force microscope (AFM respectively. Films optical characteristics were studied using UV-VIS spectrophotometer. XRD revealed the presence of pure SnO2 polycrystalline thin film with a tetragonal rutile structure. The SEM and AFM observations confirmed the granular morphology with presence of pores in the film surface. The prepared film was tested in various organic vapors (ethanol, methanol and acetone at ambient operating temperature (25 °C ± 2 °C. The obtained results suggested that SnO2 is more sensitive to ethanol vapor with a maximum sensitivity of 35% higher than to methanol and acetone vapors (1% and 3%. The realized SnO2 based sensor demonstrated fast response and recovery times as revealed by the values of 2 s to 3 s towards 47 ppm of ethanol vapor. Keywords: SnO2 thin film, Sensitivity, XRD, SEM, AFM, UV–visible

  18. Monolithic microwave integrated circuit water vapor radiometer

    Science.gov (United States)

    Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

    1991-01-01

    A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

  19. Water vapor and Gas Transport through Polymeric Membranes

    NARCIS (Netherlands)

    Metz, S.J.

    2003-01-01

    Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

  20. Enhanced Performance of Photoelectrochemical Water Splitting with ITO@α-Fe2O3 Core-Shell Nanowire Array as Photoanode.

    Science.gov (United States)

    Yang, Jie; Bao, Chunxiong; Yu, Tao; Hu, Yingfei; Luo, Wenjun; Zhu, Weidong; Fu, Gao; Li, Zhaosheng; Gao, Hao; Li, Faming; Zou, Zhigang

    2015-12-09

    Hematite (α-Fe2O3) is one of the most promising candidates for photoelectrodes in photoelectrochemical water splitting system. However, the low visible light absorption coefficient and short hole diffusion length of pure α-Fe2O3 limits the performance of α-Fe2O3 photoelectrodes in water splitting. Herein, to overcome these drawbacks, single-crystalline tin-doped indium oxide (ITO) nanowire core and α-Fe2O3 nanocrystal shell (ITO@α-Fe2O3) electrodes were fabricated by covering the chemical vapor deposited ITO nanowire array with compact thin α-Fe2O3 nanocrystal film using chemical bath deposition (CBD) method. The J-V curves and IPCE of ITO@α-Fe2O3 core-shell nanowire array electrode showed nearly twice as high performance as those of the α-Fe2O3 on planar Pt-coated silicon wafers (Pt/Si) and on planar ITO substrates, which was considered to be attributed to more efficient hole collection and more loading of α-Fe2O3 nanocrystals in the core-shell structure than planar structure. Electrochemical impedance spectra (EIS) characterization demonstrated a low interface resistance between α-Fe2O3 and ITO nanowire arrays, which benefits from the well contact between the core and shell. The stability test indicated that the prepared ITO@α-Fe2O3 core-shell nanowire array electrode was stable under AM1.5 illumination during the test period of 40,000 s.

  1. Cold Water Vapor in the Barnard 5 Molecular Cloud

    Science.gov (United States)

    Wirstrom, E. S.; Charnley, S. B.; Persson, C. M.; Buckle, J. V.; Cordiner, M. A.; Takakuwa, S.

    2014-01-01

    After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold ((is) approximately 10 K) water vapor has been detected-L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work-likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 110-101) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

  2. COLD WATER VAPOR IN THE BARNARD 5 MOLECULAR CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Wirström, E. S.; Persson, C. M. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden); Charnley, S. B.; Cordiner, M. A. [Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States); Buckle, J. V. [Astrophysics Group, Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Takakuwa, S., E-mail: eva.wirstrom@chalmers.se [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China)

    2014-06-20

    After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold (∼10 K) water vapor has been detected—L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work—likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H{sub 2}O (J = 1{sub 10}-1{sub 01}) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

  3. Advancements in water vapor electrolysis technology. [for Space Station ECLSS

    Science.gov (United States)

    Chullen, Cinda; Heppner, Dennis B.; Sudar, Martin

    1988-01-01

    The paper describes a technology development program whose goal is to develop water vapor electrolysis (WVE) hardware that can be used selectively as localized topping capability in areas of high metabolic activity without oversizing the central air revitalization system on long-duration manned space missions. The WVE will be used primarily to generate O2 for the crew cabin but also to provide partial humidity control by removing water vapor from the cabin atmosphere. The electrochemically based WVE interfaces with cabin air which is controlled in the following ranges: dry bulb temperature of 292 to 300 K; dew point temperature of 278 to 289 K; relative humidity of 25 to 75 percent; and pressure of 101 + or - 1.4 kPa. Design requirements, construction details, and results for both single-cell and multicell module testing are presented, and the preliminary sizing of a multiperson subsystem is discussed.

  4. β-Ga2O3 versus ε-Ga2O3: Control of the crystal phase composition of gallium oxide thin film prepared by metal-organic chemical vapor deposition

    Science.gov (United States)

    Zhuo, Yi; Chen, Zimin; Tu, Wenbin; Ma, Xuejin; Pei, Yanli; Wang, Gang

    2017-10-01

    Gallium oxide thin films of β and ε phase were grown on c-plane sapphire using metal-organic chemical vapor deposition and the phase compositions were analyzed using X-ray diffraction. The epitaxial phase diagram was constructed as a function of the growth temperature and VI/III ratio. A low growth temperature and low VI/III ratio were beneficial for the formation of hexagonal-type ε-Ga2O3. Further structure analysis revealed that the epitaxial relationship between ε-Ga2O3 and c-plane sapphire is ε-Ga2O3 (0001) || Al2O3 (0001) and ε-Ga2O3 || Al2O3 . The structural evolution of the mixed-phase sample during film thickening was investigated. By reducing the growth rate, the film evolved from a mixed phase to the energetically favored ε phase. Based on these results, a Ga2O3 thin film with a phase-pure ε-Ga2O3 upper layer was successfully obtained.

  5. Homoepitaxial growth of a-plane GaN layers by reaction between Ga2O vapor and NH3 gas

    International Nuclear Information System (INIS)

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

    2015-01-01

    Growth of high-quality a-plane GaN layers was performed by reaction between Ga 2 O vapor and NH 3 gas at a high temperature. Smooth a-plane GaN epitaxial layers were obtained on a-plane GaN seed substrates sliced from thick c-plane GaN crystals. Growth rate increased with increasing Ga 2 O partial pressure. An a-plane GaN layer with a growth rate of 48 μm/h was obtained. The X-ray rocking curve (XRC) measurement showed that the full widths at half maximum (FWHMs) of GaN(112-bar0) with the incident beam parallel and perpendicular to the [0001] direction were 29–43 and 29–42 arcsec, respectively. Secondary ion mass spectrometry (SIMS) measurement revealed that oxygen concentration decreased at a high temperature. These results suggest that growth of a-GaN layers using Ga 2 O vapor and NH 3 gas at a high temperature enables the generation of high-quality crystals. (author)

  6. Water-vapor pressure control in a volume

    Science.gov (United States)

    Scialdone, J. J.

    1978-01-01

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

  7. Temporal Variations of Water Vapor in the Coma of 67P/Churyumov-Gerasimenko as Observed by Rosetta’s Alice FUV Spectrograph

    Science.gov (United States)

    Steffl, Andrew J.; Feaga, Lori M.; A'Hearn, Michael; Bertaux, Jean-Loup; Feldman, Paul D.; Keeney, Brian A.; Knight, Matthew M.; Medina, Richard; Noonan, John; Parker, Joel Wm.; Pineau, Jon; Schindhelm, Eric; Stern, S. Alan; Versteeg, Maarten H.; Vervack, Ronald J.; Weaver, Harold A.

    2017-10-01

    During the Rosetta mission, the Alice far-ultraviolet (FUV) imaging spectrograph obtained spatially-resolved spectra of the coma and nucleus of comet 67P/Churyumov-Gerasimenko over the wavelength range of 700-2050Å. Typically, Alice detected emissions from the neutral atomic daughter and granddaughter products (H, O, C, and S) of the primary molecular species in the coma: H2O, CO2, CO, and O2. However, during a six-month period centered near perihelion, Alice directly detected water vapor in absorption of sunlight reflected from the nucleus. We present here analyses of the water vapor column density as measured by the Alice FUV spectrograph. Alice is sensitive to water vapor at column densities greater than ~1016 cm-2 along the sum of the Sun-nucleus and nucleus-spacecraft lines of sight. Due to the excellent temporal coverage provided by the Alice instrument (exposures were typically obtained every 5-10 minutes), we are able to show variations of water vapor in the coma caused by the changing heliocentric distance of the comet, the comet’s ~12-hour rotation period, and short-term outbursts. We compare our water vapor column densities to those derived from other instruments aboard the Rosetta spacecraft and use models to estimate the water production rate.Rosetta is an ESA mission with contributions from its member states and NASA. The Alice team acknowledges continuing support from NASA’s Jet Propulsion Laboratory through contract 1336850 to the Southwest Research Institute.

  8. Energetic particle induced desorption of water vapor cryo-condensate

    International Nuclear Information System (INIS)

    Menon, M.M.; Owen, L.W.; Simpkins, J.E.; Uckan, T.; Mioduszewski, P.K.

    1990-01-01

    An in-vessel cryo-condensation pump is being designed for the Advanced Divertor configuration of the DIII-D tokamak. To assess the importance of possible desorption of water vapor from the cryogenic surfaces of the pump due to impingement of energetic particles from the plasma, a 77 K surface on which a thin layer of water vapor was condensed was exposed to a tenuous plasma (density = 2 x 10 10 cm -3 , electron temperature = 3 eV). Significant desorption of the condensate occurred, suggesting that impingement of energeticparticles (10 eV) at flux levels of ∼10 16 cm 2 s -1 on cryogenic surfaces could potentially induce impurity problems in the tokamak plasma. A pumping configuration is presented in which this problem is minimized without sacrificing the pumping speed

  9. Optimization of band-pass filtering parameters of a Raman lidar detecting atmospheric water vapor

    International Nuclear Information System (INIS)

    Cao, Kai-Fa; Hu, Shun-Xing; Wang, Ying-jian

    2012-01-01

    It is very important for daytime Raman lidar measurement of water vapor to determine the parameters of a band-pass filter, which are pertinent to the lidar signal to noise ratio (SNR). The simulated annealing (SA) algorithm method has an advantage in finding the extremum of a certain cost function. In this paper, the Raman spectrum of water vapor is simulated and then a first realization of a simulated annealing algorithm in the optimization of a band-pass filter of a Raman lidar system designed to detect daytime water vapor is presented. The simulated results indicate that the narrow band-pass filter has higher SNR than the wide filter does but there would be an increase in the temperature sensitivity of a narrowband Raman water vapor lidar in the upper troposphere. The numerical simulation indicates that the magnitude of the temperature dependent effect can reach 3.5% or more for narrow band-pass Raman water vapor measurements so it is necessary to consider a new water vapor Raman lidar equation that permits the temperature sensitivity of these equations to be confined to a single term. (paper)

  10. Synthesis of highly efficient Mn2O3 catalysts for CO oxidation derived from Mn-MIL-100

    Science.gov (United States)

    Zhang, Xiaodong; Li, Hongxin; Hou, Fulin; Yang, Yang; Dong, Han; Liu, Ning; Wang, Yuxin; Cui, Lifeng

    2017-07-01

    In this work, metal-organic frameworks (MOFs) Mn-MIL-100 were first prepared, which were next used as templates to obtain the irregular porous Mn2O3 cubes through calcination with air at different temperature. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), H2-temperature program reduction (H2-TPR) and X-ray photoelectron spectroscopic (XPS). The catalytic activity for CO oxidation over Mn2O3 catalysts was investigated. It was found that calcination temperature had a strong effect on the structure and catalytic activity of Mn2O3 catalyst. Mn2O3 catalyst obtained by calcined at 700 °C (Mn2O3-700) showed a smaller specific surface area, but displayed a high catalytic activity and excellent stability with a complete CO conversion temperature (T98) of 240 °C, which was attributed to the unique structure, a high quantity of surface active oxygen species, smaller particle size, oxygen vacancies and good low temperature reduction behavior. The effect of water vapor on catalytic activity was also examined. The introduction of water vapor to the feedstock induced a positive effect on CO oxidation over Mn2O3-700 catalyst. Furthermore, no obvious drop is observed in activity over catalysts even in the presence of water vapor during 48 h.

  11. Exchange reaction between tritiated hydrogen and water vapor

    International Nuclear Information System (INIS)

    Yamada, Koichi; Takano, Kenichi; Watanabe, Tamaki.

    1979-01-01

    Exchange reaction of tritiated hydrogen to water vapor under the condition of tritium gas concentration between 1 μCi/l and 1 mCi/l was studied. Tritium gas with hydrogen gas of 5 Torr and water of 20 mg were enclosed in a Pyrex glass ampule with volume of about 100 ml. The mixed gas with water vapor was heated with electric furnace. The heating time was between 2 and 100 hr, and the temperature was 776, 725, 675, 621, and 570.5 0 K. After heating, tritiated water was trapped with liquid nitrogen, and counted with a liquid scintillation counter. The radioactive concentration of initial tritiated hydrogen was measured with a calibrated ionization chamber. The main results obtained are as follows; 1) the concentration of produced tritiated water is well proportioned to that of initial tritiated hydrogen, 2) the activation energy of exchange reaction from tritiated hydrogen to tritiated water is 26.2 kcal/mol and that of inverse reaction is 27.4 kcal/mol, 3) the reaction rate at room temperature which calculated with activation energy is 1.04 x 10 -13 day -1 , and then exchange reaction at room temperature is negligible. (author)

  12. Water vapor permeabilities through polymers: diffusivities from experiments and simulations

    International Nuclear Information System (INIS)

    Seethamraju, Sindhu; Ramamurthy, Praveen Chandrashekarapura; Madras, Giridhar

    2014-01-01

    This study experimentally determines water vapor permeabilities, which are subsequently correlated with the diffusivities obtained from simulations. Molecular dynamics (MD) simulations were used for determining the diffusion of water vapor in various polymeric systems such as polyethylene, polypropylene, poly (vinyl alcohol), poly (vinyl acetate), poly (vinyl butyral), poly (vinylidene chloride), poly (vinyl chloride) and poly (methyl methacrylate). Cavity ring down spectroscopy (CRDS) based methodology has been used to determine the water vapor transmission rates. These values were then used to calculate the diffusion coefficients for water vapor through these polymers. A comparative analysis is provided for diffusivities calculated from CRDS and MD based results by correlating the free volumes. (paper)

  13. The vertical distribution of Mars water vapor

    Science.gov (United States)

    Davies, D. W.

    1979-01-01

    Analysis of observations made from the Viking 1 Orbiter indicates that the water vapor over the Viking 1 landing site is uniformly mixed with the atmosphere and not concentrated near the surface. The analysis incorporates the effects of atmospheric scattering and explains why previous earth-based observations showed a strong diurnal variation in water content. It also explains the lack of an early morning fog and removes the necessity of daily exchange of large amounts of water between the surface and the atmosphere. A water vapor volume mixing ratio of 1.5 x 10 to the -4th is inferred for the Viking 1 site in late summer.

  14. Differential Absorption Radar: An Emerging Technology for Remote Sounding of Water Vapor Within Clouds

    Science.gov (United States)

    Lebsock, M. D.; Millan Valle, L. F.; Cooper, K. B.; Siles, J.; Monje, R.

    2017-12-01

    We present the results of our efforts to build and demonstrate the first Differential Absorption Radar (DAR), which will provide unique capabilities to remotely sound for water vapor within cloudy and precipitating atmospheres. The approach leverages multiple radar channels located near the 183 GHz water vapor absorption feature to simultaneously derive microphysical and water vapor profiles. The DAR technique has the potential to neatly complement existing water vapor sounding techniques such as infrared and microwave sounding and GPS radio occultation. These precisions rival those of existing water vapor remote sensing instruments. The approach works best from above clouds because the water vapor burden and line width increases towards the Earth surface allowing increased sampling from the top-down compared with bottom-up. From an airborne or satellite platform channels can be selected that target either upper-tropospheric or lower-tropospheric clouds. Our theoretical studies suggest that the water vapor concentration can be retrieved to within 1-3 gm-3 and the column integrated water vapor can be retrieved to within 1 kgm-2. The high-frequency radar is only recently enabled by technological advances that have allowed us to demonstrate 0.5 W of continuous power near 183 GHz. We are currently developing an airborne DAR using a Frequency Modulated Continuous Wave (FMCW) architecture with a quasi-optical duplexer providing 80 dB of transmit/receive isolation. A prototype of this instrument recently made the first ever range resolved DAR measurements of humidity out to several hundred meters during a light rain event at JPL. The spectral dependence of the attenuation was in excellent agreement with the predicted attenuation based on nearby weather stations, proving for the first time the feasibility of the concept. A major impediment to implementing DAR is the international regulation of radio-frequency transmissions below 300 GHz. The major roadblocks and potential

  15. Open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water

    International Nuclear Information System (INIS)

    Hou Shaobo; Li Huacong; Zhang Hefei

    2007-01-01

    This paper presents an open air-vapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6 o C. Its refrigeration depends mainly on both air and vapor, more efficient than a conventional air cycle, and the use of turbo-machinery makes this possible. This system could use the cool in the cool water, which could not be used to cool air directly. Also, the heat rejected from this system could be used to heat cool water to 33-40 o C. The sensitivity analysis of COP to η c and η t and the simulated results T 4 , T 7 , T 8 , q 1 , q 2 and W m of the cycle are given. The simulations show that the COP of this system depends mainly on T 7 , η c and η t and varies with T 3 or T wet and that this cycle is feasible in some regions, although the COP is sensitive to the efficiencies of the axial compressor and turbine. The optimum pressure ratio in this system could be lower, and this results in a fewer number of stages of the axial compressor. Adjusting the rotation speed of the axial compressor can easily control the pressure ratio, mass flow rate and the refrigerating capacity. The adoption of this cycle will make the air conditioned room more comfortable and reduce the initial investment cost because of the obtained very low temperature air. Humid air is a perfect working fluid for central air conditioning and no cost to the user. The system is more efficient because of using cool water to cool the air before the turbine. In addition, pinch technology is a good method to analyze the wet air heat exchange with water

  16. Study and mitigation of calibration factor instabilities in a water vapor Raman lidar

    Directory of Open Access Journals (Sweden)

    L. David

    2017-07-01

    Full Text Available We have investigated calibration variations in the Rameau water vapor Raman lidar. This lidar system was developed by the Institut National de l'Information Géographique et Forestière (IGN together with the Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS. It aims at calibrating Global Navigation Satellite System (GNSS measurements for tropospheric wet delays and sounding the water vapor variability in the lower troposphere. The Rameau system demonstrated good capacity in retrieving water vapor mixing ratio (WVMR profiles accurately in several campaigns. However, systematic short-term and long-term variations in the lidar calibration factor pointed to persistent instabilities. A careful testing of each subsystem independently revealed that these instabilities are mainly induced by mode fluctuations in the optic fiber used to couple the telescope to the detection subsystem and by the spatial nonuniformity of the photomultiplier photocathodes. Laboratory tests that replicate and quantify these instability sources are presented. A redesign of the detection subsystem is presented, which, combined with careful alignment procedures, is shown to significantly reduce the instabilities. Outdoor measurements were performed over a period of 5 months to check the stability of the modified lidar system. The calibration changes in the detection subsystem were monitored with lidar profile measurements using a common nitrogen filter in both Raman channels. A short-term stability of 2–3 % and a long-term drift of 2–3 % per month are demonstrated. Compared to the earlier Development of Methodologies for Water Vapour Measurement (DEMEVAP campaign, this is a 3-fold improvement in the long-term stability of the detection subsystem. The overall water vapor calibration factors were determined and monitored with capacitive humidity sensor measurements and with GPS zenith wet delay (ZWD data. The changes in the water vapor calibration factors

  17. Precipitable water and vapor flux between Belem and Manaus

    International Nuclear Information System (INIS)

    Marques, J.

    1977-01-01

    The water vapor flux and precipitable water was computated over the natural Amazon forest in the stretch between Belem and Manaus for 1972. The atmospheric branch of hidrological cycle theory was applied and the most significant conclusions on an annual basis are: Atlantic Ocean water vapor contributes 52% to the regional precipitation and is significant the role played by local evapotranspiration in the precipitation in the area; there were signs of the phenomenon of water vapor recycling nearly throughout the year. Evapotranspiration contributes to 48% of the precipitations in the area studied. The real evapotranspiration estimated by this method was 1,000mm year - 1 [pt

  18. Isobaric (vapor + liquid) equilibria for the ternary system of (ethanol + water + 1,3-propanediol) and three constituent binary systems at P = 101.3 kPa

    International Nuclear Information System (INIS)

    Lai, Hung-Sheng; Lin, Yi-Feng; Tu, Chein-Hsiun

    2014-01-01

    Highlights: • We report VLE data at 101.3 kPa for mixtures of ethanol, water, and 1,3-propanediol. • The VLE data were correlated by the Wilson, NRTL, and UNIQUAC models. • The ternary VLE data were predicted from binary VLE data using the three models. • The VLE effect of 1,3-propanediol on the azeotropic ethanol + water mixture was studied. • The azeotropic point of ethanol + water disappears at 30 wt% of 1,3-propanediol. -- Abstract: Isobaric (vapor + liquid) equilibrium (VLE) at P = 101.3 kPa have been measured for the ternary system of (ethanol + water + 1,3-propanediol) and for the corresponding binary systems of (ethanol + water), (ethanol + 1,3-propanediol), and (water + 1,3-propnaediol) using a Hunsmann-type equilibrium still with circulation of both vapor and liquid phases. The ternary mixtures were prepared by mixing ethanol and pure water with three concentrations (10, 30, and 50) wt% of 1,3-propanediol in the overall liquid mixtures in order to study the effect of 1,3-propanediol on the VLE of (ethanol + water). The equilibrium compositions of mixtures were analyzed by gas–liquid chromatography. The relative volatilities of ethanol with respect to water were also determined. The results of the investigation indicate the disappearance of the binary azeotrope between ethanol and water when the concentration of 1,3-propanediol is up to 30 wt%. The liquid activity coefficients were calculated using the modified Raoult’s law. The thermodynamic consistency of the VLE data was performed for the three binary systems using Van Ness direct test. The new binary and ternary VLE data were successfully correlated using the Wilson, NRTL, and UNIQUAC models, for which the binary interaction parameters are reported

  19. The reaction kinetics of lithium salt with water vapor

    International Nuclear Information System (INIS)

    Balooch, M.; Dinh, L.N.; Calef, D.F.

    2002-01-01

    The interaction of lithium salt (LiH and/or LiD) with water vapor in the partial pressure range of 10 -5 -2657 Pa has been investigated. The reaction probability of water with LiH cleaved in an ultra high vacuum environment was obtained using the modulated molecular beam technique. This probability was 0.11 and independent of LiH surface temperature, suggesting a negligible activation energy for the reaction in agreement with quantum chemical calculations. The value gradually reduced, however, to 0.007 as the surface concentration of oxygen containing product approached full coverage. As the film grew beyond a monolayer, the phase lag of hydrogen product increased from 0 deg. C to 20 deg. C and the reaction probability reduced further until it approached our detection limit (∼10 -4 ). This phase lag was attributed to a diffusion-limited process in this regime. For micrometer thick hydroxide films grown in high moisture concentration environment on LiD and LiH, the reaction probability reduced to ∼4x10 -7 and was independent of exposure time. In this regime of thick hydroxide films (LiOH and/or LiOD), microcracks generated in the films to release stress provided easier pathways for moisture to reach the interface. A modified microscope, capable of both atomic force microscopy and nanoindentation, was also employed to investigate the surface morphology of hydroxide monohydrate (LiOH · H 2 O and/or LiOD · H 2 O) grown on hydroxide at high water vapor partial pressures and the kinetics of this growth

  20. Effect of phase interaction on catalytic CO oxidation over the SnO_2/Al_2O_3 model catalyst

    International Nuclear Information System (INIS)

    Chai, Shujing; Bai, Xueqin; Li, Jing; Liu, Cheng; Ding, Tong; Tian, Ye; Liu, Chang; Xian, Hui; Mi, Wenbo; Li, Xingang

    2017-01-01

    Highlights: • Activity for CO oxidation is greatly enhanced by interaction between SnO_2 and Al_2O_3. • Interaction between SnO_2 and Al_2O_3 phases can generate oxygen vacancies. • Oxygen vacancies play an import role for catalytic CO oxidation. • Sn"4"+ cations are the effective sites for catalytic CO oxidation. • Langmuir-Hinshelwood model is preferred for catalytic CO oxidation. - Abstract: We investigated the catalytic CO oxidation over the SnO_2/Al_2O_3 model catalysts. Our results show that interaction between the Al_2O_3 and SnO_2 phases results in the significantly improved catalytic activity because of the formation of the oxygen vacancies. The oxygen storage capacity of the SnO_2/Al_2O_3 catalyst prepared by the physically mixed method is nearly two times higher than that of the SnO_2, which probably results from the change of electron concentration on the interface of the SnO_2 and Al_2O_3 phases. Introducing water vapor to the feeding gas would a little decrease the activity of the catalysts, but the reaction rate could completely recover after removal of water vapor. The kinetics results suggest that the surface Sn"4"+ cations are effective CO adsorptive sites, and the surface adsorbed oxygen plays an important role upon CO oxidation. The reaction pathways upon the SnO_2-based catalysts for CO oxidation follow the Langmuir-Hinshelwood model.

  1. Absorption coefficients for water vapor at 193 nm from 300 to 1073 K

    Science.gov (United States)

    Kessler, W. J.; Carleton, K. L.; Marinelli, W. J.

    1993-01-01

    Measurements of the water absorption coefficient at 193 nm from 300 to 1073 K are reported. The measurements were made using broadband VUV radiation and a monochromator-based detection system. The water vapor was generated by a saturator and metered into a flowing, 99 cm absorption cell via a water vapor mass flow meter. The 193 nm absorption coefficient measurements are compared to room temperature and high temperature shock tube measurements with good agreement. The absorption can be parameterized by a nu3 vibrational mode reaction coordinate and the thermal population of the nu3 mode.

  2. Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region

    Science.gov (United States)

    Thankamani Akhil Raj, Sivan; Venkat Ratnam, Madineni; Narayana Rao, Daggumati; Venkata Krishna Murthy, Boddam

    2018-01-01

    We have investigated the long-term trends in and variabilities of stratospheric ozone, water vapor and temperature over the Indian monsoon region using the long-term data constructed from multi-satellite (Upper Atmosphere Research Satellite (UARS MLS and HALOE, 1993-2005), Aura Microwave Limb Sounder (MLS, 2004-2015), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER, 2002-2015) on board TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics)) observations covering the period 1993-2015. We have selected two locations, namely, Trivandrum (8.4° N, 76.9° E) and New Delhi (28° N, 77° E), covering northern and southern parts of the Indian region. We also used observations from another station, Gadanki (13.5° N, 79.2° E), for comparison. A decreasing trend in ozone associated with NOx chemistry in the tropical middle stratosphere is found, and the trend turned to positive in the upper stratosphere. Temperature shows a cooling trend in the stratosphere, with a maximum around 37 km over Trivandrum (-1.71 ± 0.49 K decade-1) and New Delhi (-1.15 ± 0.55 K decade-1). The observed cooling trend in the stratosphere over Trivandrum and New Delhi is consistent with Gadanki lidar observations during 1998-2011. The water vapor shows a decreasing trend in the lower stratosphere and an increasing trend in the middle and upper stratosphere. A good correlation between N2O and O3 is found in the middle stratosphere (˜ 10 hPa) and poor correlation in the lower stratosphere. There is not much regional difference in the water vapor and temperature trends. However, upper stratospheric ozone trends over Trivandrum and New Delhi are different. The trend analysis carried out by varying the initial year has shown significant changes in the estimated trend.

  3. O3 fast and simple treatment-enhanced p-doped in Spiro-MeOTAD for CH3NH3I vapor-assisted processed CH3NH3PbI3 perovskite solar cells

    Institute of Scientific and Technical Information of China (English)

    En-Dong Jia; Xi Lou; Chun-Lan Zhou; Wei-Chang Hao; Wen-Jing Wang

    2017-01-01

    We demonstrate a simple and fast post-deposition treatment with high process compatibility on the hole transport material (HTM) Spiro-MeOTAD in vapor-assisted solution processed methylammonium lead triiodide (CH3NH3PbI3)-based solar cells.The prepared Co-doped p-type Spiro-MeOTAD films are treated by O3 at room temperature for 5 min,10 min,and 20 min,respectively,prior to the deposition of the metal electrodes.Compared with the traditional oxidation of Spiro-MeOTAD films overnight in dry air,our fast O3 treatment of HTM at room temperature only needs just 10 min,and a relative 40.3% increment in the power conversion efficiency is observed with respect to the result of without-treated perovskite solar cells.This improvement of efficiency is mainly attributed to the obvious increase of the fill factor and short-circuit current density,despite a slight decrease in the open-circuit voltage.Ultraviolet photoelectron spectroscopy (UPS) and Hall effect measurement method are employed in our study to determine the changes of properties after O3 treatment in HTM.It is found that after the HTM is exposed to O3,its p-type doping level is enhanced.The enhancement of conductivity and Hall mobility of the film,resulting from the improvement in p-doping level of HTM,leads to better performances of perovskite solar cells.Best power conversion efficiencies (PCEs) of 13.05% and 16.39% are achieved with most properly optimized HTM via CH3NH3I vapor-assisted method and traditional single-step method respectively.

  4. Importance Profiles for Water Vapor

    Science.gov (United States)

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

    2017-11-01

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

  5. Atmospheric water vapor: Distribution and Empirical estimation in the atmosphere of Thailand

    Science.gov (United States)

    Phokate, S.

    2017-09-01

    Atmospheric water vapor is a crucial component of the Earth’s atmosphere, which is shown by precipitable water vapor. It is calculated from the upper air data. In Thailand, the data were collected from four measuring stations located in Chiang Mai, Ubon Ratchathani, Bangkok, and Songkhla during the years 1998-2013. The precipitable water vapor obtained from this investigation were used to define an empirical model associated with the vapor pressure, which is a surface data at the same stations. The result shows that the relationship has a relatively high level of reliability. The precipitable water vapor obtained from the upper air data is nearly equal to the value from the model. The model was used to calculate the precipitable water vapor from the surface data 85 stations across the country. The result shows that seasonal change of the precipitable water vapor was low in the dry season (November-April) and high in the rainy season (May-October). In addition, precipitable water vapor varies along the latitudes of the stations. The high value obtains for low latitudes, but it is low for high latitudes.

  6. Water Vapor in the Middle Atmosphere of Venus from the Data of the Venera-15 IR Fourier Spectrometer

    Science.gov (United States)

    Ignat'ev, N. I.; Moroz, V. I.; Zasova, L. V.; Khatuntsev, I. V.

    In 1983, the Fourier spectrometer experiment onboard Venera-15 returned spectra of IR radiation (6-50 micron) of the Venusian atmosphere which contained information about temperature, aerosols, and minor constituents, including water vapor. The currently available techniques of radiation-transfer modeling and the H2O-abundance reconstruction allowed us to reanalyze these data, and the most recent results of this analysis are presented here. Most of the measurements are in the range 5-15 ppm. Temporal and spatial variations of the water-vapor abundance were measured. The estimates of H2O abundance calculated from the spectra refer to a certain altitude approximately determined by the level where the optical depth tau in the aerosol continuum near the H2O bands region is close to unity. This altitude varies from 62.5 +/- 2 km at low latitudes to 56 +/- 2 km at high altitudes, but the mean measured water-vapor abundance is found to be roughly the same for both areas, about 10 ppm. At low and middle latitudes, the H2O mixing ratio is maximum on the dayside of the planet and minimum on the nightside. Although the direct reconstruction of the H2O vertical profile from the spectra failed, its indirect estimates confirming the decrease of the mixing ratio with altitude were obtained.

  7. Correlation of vapor - liquid equilibrium data for acetic acid - isopropanol - water - isopropyl acetate mixtures

    Directory of Open Access Journals (Sweden)

    B. A. Mandagarán

    2006-03-01

    Full Text Available A correlation procedure for the prediction of vapor - liquid equilibrium of acetic acid - isopropanol - water - isopropyl acetate mixtures has been developed. It is based on the NRTL model for predicting liquid activity coefficients, and on the Hayden-O'Connell second virial coefficients for predicting the vapor phase of systems containing association components. When compared with experimental data the correlation shows a good agreement for binary and ternary data. The correlation also shows good prediction for reactive quaternary data.

  8. The annual cycle of stratospheric water vapor in a general circulation model

    Science.gov (United States)

    Mote, Philip W.

    1995-01-01

    The application of general circulation models (GCM's) to stratospheric chemistry and transport both permits and requires a thorough investigation of stratospheric water vapor. The National Center for Atmospheric Research has redesigned its GCM, the Community Climate Model (CCM2), to enable studies of the chemistry and transport of tracers including water vapor; the importance of water vapor to the climate and chemistry of the stratosphere requires that it be better understood in the atmosphere and well represented in the model. In this study, methane is carried as a tracer and converted to water; this simple chemistry provides an adequate representation of the upper stratospheric water vapor source. The cold temperature bias in the winter polar stratosphere, which the CCM2 shares with other GCM's, produces excessive dehydration in the southern hemisphere, but this dry bias can be ameliorated by setting a minimum vapor pressure. The CCM2's water vapor distribution and seasonality compare favorably with observations in many respects, though seasonal variations including the upper stratospheric semiannual oscillation are generally too small. Southern polar dehydration affects midlatitude water vapor mixing ratios by a few tenths of a part per million, mostly after the demise of the vortex. The annual cycle of water vapor in the tropical and northern midlatitude lower stratosphere is dominated by drying at the tropical tropopause. Water vapor has a longer adjustment time than methane and had not reached equilibrium at the end of the 9 years simulated here.

  9. Surface termination structure of α-Ga{sub 2}O{sub 3} film grown by mist chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tamba, Daiki; Kubo, Osamu, E-mail: okubo@eei.eng.osaka-u.ac.jp; Osaka, Shun; Takahashi, Kazuki; Tabata, Hiroshi; Katayama, Mitsuhiro [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan); Oda, Masaya [Photonics and Electronics Science and Engineering Center, Graduate School of Engineering, Kyoto University, Kyoto 615-8520 (Japan); FLOSFIA Inc., 1-36 Goryoohara, Kyoto 615-8245 (Japan); Kaneko, Kentaro; Fujita, Shizuo [Photonics and Electronics Science and Engineering Center, Graduate School of Engineering, Kyoto University, Kyoto 615-8520 (Japan)

    2016-06-20

    The surface structure of α-Ga{sub 2}O{sub 3}(0001) grown on an α-Al{sub 2}O{sub 3}(0001) substrate by mist chemical vapor deposition was studied by coaxial impact-collision ion scattering spectroscopy (CAICISS) and atomic force microscopy (AFM). The minimum step height observed in the AFM image was 0.21 ± 0.01 nm, coinciding with the height of three atomic layers of α-Ga{sub 2}O{sub 3}(0001). It was revealed by CAICISS analysis that the surface of α-Ga{sub 2}O{sub 3}(0001) is terminated by a Ga layer followed by an O layer, which is consistent with the surface termination of α-Al{sub 2}O{sub 3}(0001). A structural model taking surface relaxation into account was also constructed by fitting the simulated curve for the azimuth angle dependence of the Ga intensity to the experimental dependence. The resultant structural model is similar to the model of an α-Al{sub 2}O{sub 3}(0001) surface, which indicates analogous behavior in corundum crystals.

  10. Development of an Airborne Micropulse Water Vapor DIAL

    Science.gov (United States)

    Nehrir, A. R.; Ismail, S.

    2012-12-01

    Water vapor plays a key role in many atmospheric processes affecting both weather and climate. Airborne measurements of tropospheric water vapor profiles have been a longstanding observational need to not only the active remote sensing community but also to the meteorological, weather forecasting, and climate/radiation science communities. Microscale measurements of tropospheric water vapor are important for enhancing near term meteorological forecasting capabilities while mesoscale and synopticscale measurements can lead to an enhanced understanding of the complex coupled feedback mechanisms between water vapor, temperature, aerosols, and clouds. To realize tropospheric measurements of water vapor profiles over the microscale-synopticscale areas of meteorological interest, a compact and cost effective airborne micropulse differential absorption lidar (DIAL) is being investigated using newly emerging semiconductor based laser technology. Ground based micropulse DIAL (MPD) measurements of tropospheric water vapor and aerosol profiles up to 6 km and 15 km, respectively, have been previously demonstrated using an all semiconductor based laser transmitter. The DIAL transmitter utilizes a master oscillator power amplifier (MOPA) configuration where two semiconductor seed lasers are used to seed a single pass traveling wave tapered semiconductor optical amplifier (TSOA), producing up to 7μJ pulse energies over a 1 μs pulse duration at a 10 kHz pulse repetition frequency (PRF). Intercomparisons between the ground based instrument measurements and radiosonde profiles demonstrating the MPD performance under varying atmospheric conditions will be presented. Work is currently ongoing to expand upon the ground based MPD concept and to develop a compact and cost effective system capable of deployment on a mid-low altitude aircraft such as the NASA Langley B200 King Air. Initial lab experiments show that a two-three fold increase in the laser energy compared to the ground

  11. Effects of water vapor on flue gas conditioning in the electric fields with corona discharge

    Energy Technology Data Exchange (ETDEWEB)

    Liqiang, QI, E-mail: qi_liqiang@163.com; Yajuan, Zhang

    2013-07-15

    Highlights: • The influence mechanism of water vapor humidification on SO{sub 2} oxidation was analyzed. •The effects of water vapor on the specific resistance in fly ash in ESPs were reported. • The effects of water vapor on the size distribution and specific surface area of fly ash were discussed. • The adhesive characteristic of fly ash in different water vapor was experimented. -- Abstract: Sulfur dioxide (SO{sub 2}) removal via pulsed discharge nonthermal plasma in the absence of ammonia was investigated to determine how electrostatic precipitators (ESPs) can effectively collect particulate matter less than 2.5 μm in diameter from flue gas. SO{sub 2} removal increased as water vapor concentration increased. In a wet-type plasma reactor, directing a gas-phase discharge plasma toward the water film surface significantly enhanced the liquid-phase oxidation of HSO{sub 3}{sup −} to SO{sub 4}{sup 2−}. Comparisons of various absorbents revealed that the hydroxyl radical is a key factor in plasma-induced liquid-phase reactions. The resistivity, size distribution, and cohesive force of fly ash at different water vapor contents were measured using a Bahco centrifuge, which is a dust electrical resistivity test instrument, as well as a cohesive force test apparatus developed by the researchers. When water vapor content increased by 5%, fly ash resistivity in flue gas decreased by approximately two orders of magnitude, adhesive force and size increased, and specific surface area decreased. Therefore, ESP efficiency increased.

  12. Nanostructured Fe2O3/Al2O3 Adsorbent for removal of As (V from water

    Directory of Open Access Journals (Sweden)

    Faranak Akhlaghian

    2017-04-01

    Full Text Available The presence of arsenate in drinking water causes adverse health effects including skin lesions, diabetes, cancer, damage to the nervous system, and cardiovascular diseases. Therefore, the removal of As (V from water is necessary. In this work, nanostructured adsorbent Fe2O3/Al2O3 was synthesized via the sol-gel method and applied to remove arsenate from polluted waters. First, the Fe2O3 load of the adsorbent was optimized. The Fe2O3/Al2O3 adsorbent was characterized by means of XRF, XRD, ASAP, and SEM techniques. The effects of the operating conditions of the batch process of As (V adsorption such as pH, adsorbent dose, contact time, and initial concentration of As (V solution were studied, and optimized. The thermodynamic study of the process showed that arsenate adsorption was endothermic. The kinetic model corresponded to the pseudo-second-order model. The Langmuir adsorption isotherm was better fitted to the experimental data. The Fe2O3/Al2O3 adsorbent was immobilized on leca granules and applied for As (V adsorption. The results showed that the immobilization of Fe2O3/Al2O3 on leca particles improved the As (V removal efficiency.

  13. Vaporization of fault water during seismic slip

    Science.gov (United States)

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

    2017-06-01

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

  14. Core-shell SrTiO3/graphene structure by chemical vapor deposition for enhanced photocatalytic performance

    Science.gov (United States)

    He, Chenye; Bu, Xiuming; Yang, Siwei; He, Peng; Ding, Guqiao; Xie, Xiaoming

    2018-04-01

    Direct growth of high quality graphene on the surface of SrTiO3 (STO) was realized through chemical vapor deposition (CVD), to construct few-layer 'graphene shell' on every STO nanoparticle. The STO/graphene composite shows significantly enhanced UV light photocatalytic activity compared with the STO/rGO reference. Mechanism analysis confirms the role of special core-shell structure and chemical bond (Tisbnd C) for rapid interfacial electron transfer and effective electron-hole separation.

  15. Visualization of Atmospheric Water Vapor Data for SAGE

    Science.gov (United States)

    Kung, Mou-Liang; Chu, W. P. (Technical Monitor)

    2000-01-01

    The goal of this project was to develop visualization tools to study the water vapor dynamics using the Stratospheric Aerosol and Gas Experiment 11 (SAGE 11) water vapor data. During the past years, we completed the development of a visualization tool called EZSAGE, and various Gridded Water Vapor plots, tools deployed on the web to provide users with new insight into the water vapor dynamics. Results and experiences from this project, including papers, tutorials and reviews were published on the main Web page. Additional publishing effort has been initiated to package EZSAGE software for CD production and distribution. There have been some major personnel changes since Fall, 1998. Dr. Mou-Liang Kung, a Professor of Computer Science assumed the PI position vacated by Dr. Waldo Rodriguez who was on leave. However, former PI, Dr. Rodriguez continued to serve as a research adviser to this project to assure smooth transition and project completion. Typically in each semester, five student research assistants were hired and trained. Weekly group meetings were held to discuss problems, progress, new research direction, and activity planning. Other small group meetings were also held regularly for different objectives of this project. All student research assistants were required to submit reports for conference submission.

  16. Experimental evidence of hydrogen–oxygen decoupled diffusion into BaZr0.6Ce0.25Y0.15O3−δ

    International Nuclear Information System (INIS)

    Lim, D.-K.; Im, H.-N.; Jeon, S.-Y.; Park, J.-Y.; Song, S.-J.

    2013-01-01

    The electrical properties of BaZr 0.6 Ce 0.25 Y 0.15 O 3−δ (BZCY) were studied as a function of both oxygen partial pressure (-2.65⩽log(P O 2 atm -1 )⩽-0.62) and water vapor activity (-3.33⩽log(P H 2 O atm -1 ⩽-1.3)) in the temperature range of 973–1073 K. The total conductivity slightly increased in reducing atmospheres with increasing water vapor activity because of the relative contribution to the total conductivity by the redox reaction at the given thermodynamic conditions. The partial conductivities of protons, holes and oxygen vacancies were successfully calculated, and the activation energy determined for proton transport was 0.3 ± 0.1 eV. The chemical diffusivity of oxygen at a fixed water vapor activity, D ∼ vO , could only be evaluated from Fick’s second law during oxidation and reduction at the fixed water vapor activity. However, twofold nonmonotonic conductivity relaxation behaviors were clearly confirmed in the temperature range investigated during hydration/dehydration. If P O 2 represents the fixed oxygen partial pressure, D ∼ iH is the hydrogen chemical diffusivity at P O 2 and D ∼ vH is the oxygen chemical diffusivity at P O 2 , it was observed that D ∼ iH >D ∼ vH at all experimental conditions, suggesting that the hydrogen chemical diffusion is always faster than oxygen on hydration/dehydration in the temperature range studied

  17. Adsorption of radon and water vapor on commercial activated carbons

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  18. Water vapor absorption in the atmospheric window at 239 GHz

    Science.gov (United States)

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

    1995-01-01

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

  19. An evaluation of absorption spectroscopy to monitor YBa2Cu3O7-x precursors for metal organics chemical vapor deposition processing

    International Nuclear Information System (INIS)

    Matthew Edward Thomas

    1999-01-01

    Absorption spectroscopy was evaluated as a technique to monitor the metal organics chemical vapor deposition (MOCVD) process for forming YBa 2 Cu 3 O 7-x superconducting coated conductors. Specifically, this study analyzed the feasibility of using absorption spectroscopy to monitor the MOCVD supply vapor concentrations of the organic ligand 2,2,6,6-tetramethyl-3,5-heptanedionate (TMHD) metal chelates of barium, copper, and yttrium. Ba(TMHD) 2 , Cu(TMHD) 2 , and Y(TMHD) 3 compounds have successfully been vaporized in the MOCVD processing technique to form high temperature superconducting ''coated conductors,'' a promising technology for wire fabrication. The absorption study of the barium, copper, and yttrium (TMHD) precursors was conducted in the ultraviolet wavelength region from 200nm to 400nm. To simulate the MOCVD precursor flows the Ba(TMHD) 2 , Cu(TMHD) 2 , and Y(TMHD) 3 complexes were vaporized at vacuum pressures of (0.03--10)Torr. Spectral absorption scans of each precursor were conducted to examine potential measurement wavelengths for determining vapor concentrations of each precursor via Beer's law. The experimental results show that under vacuum conditions the barium, copper, and yttrium (TMHD) precursors begin to vaporize between 90 C and 135 C, which are considerably lower vaporization temperatures than atmospheric thermal gravimetric analyses indicate. Additionally, complete vaporization of the copper and yttrium (TMHD) precursors occurred during rapid heating at temperatures between 145 C and 195 C and after heating at constant temperatures between 90 C and 125 C for approximately one hour, whereas the Ba(TMHD) 2 precursor did not completely vaporize. At constant temperatures, near constant vaporization levels for each precursor were observed for extended periods of time. Detailed spectroscopic scans at stable vaporization conditions were conducted

  20. Contrasting Effects of Central Pacific and Eastern Pacific El Nino on Stratospheric Water Vapor

    Science.gov (United States)

    Garfinkel, Chaim I.; Hurwitz, Margaret M.; Oman, Luke D.; Waugh, Darryn W.

    2013-01-01

    Targeted experiments with a comprehensive chemistry-climate model are used to demonstrate that seasonality and the location of the peak warming of sea surface temperatures dictate the response of stratospheric water vapor to El Nino. In spring, El Nino events in which sea surface temperature anomalies peak in the eastern Pacific lead to a warming at the tropopause above the warm pool region, and subsequently to more stratospheric water vapor (consistent with previous work). However, in fall and in early winter, and also during El Nino events in which the sea surface temperature anomaly is found mainly in the central Pacific, the response is qualitatively different: temperature changes in the warm pool region are nonuniform and less water vapor enters the stratosphere. The difference in water vapor in the lower stratosphere between the two variants of El Nino approaches 0.3 ppmv, while the difference between the winter and spring responses exceeds 0.5 ppmv.

  1. GOES WATER VAPOR TRANSPORT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products spanning the 1987/1988 El Nino Southern Oscillation (ENSO)...

  2. Effect of deuterium addition the vaporization of Li{sub 2}ZrO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Tonegawa, Masahisa; Suzuki, Atsushi; Yasumoto, Masaru; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ. (Japan); Roux, N

    1998-03-01

    It has been proposed to add a small amount of H{sub 2} to inert purge gas for the purpose of enhancing the release of tritium from ceramic breeder materials. However, it is pointed out that the total pressure of the lithium-containing species becomes very large by addition of H{sub 2}. In this study, the partial pressures of vapor spices under D{sub 2} addition were measured by means of high temperature mass spectrometry. When D{sub 2} was introduced the formation of LiOD(g) was observed and the total pressure of lithium-containing species was higher than the case without D{sub 2} admission. From the measured partial pressures, the enthalpy of LiOD forming reaction; Li{sub 2}ZrO{sub 3}(s) + D{sub 2}O(g) = LiOD(g) + ZrO{sub 2}(s) was calculated. Moreover, the change of the total pressure of lithium-containing species under the condition that the He + 0.1 using the pressure of D{sub 2} and D{sub 2}O as parameters. (author)

  3. Methanol reformer with water vapor and oxygen in catalysts of Cu/CeO2-ZrO2 to generate H2

    International Nuclear Information System (INIS)

    Aguila M, M.M.

    2007-01-01

    The environmental pollution is one of the problems more important to solve in the present time because its affect the quality of the alive beings' life. For such a reason alternatives have been looked for to diminish the percentage of air pollution (NO x , CO x , SO x , etc.), for they have been developed it the well-known catalytic converters. Another possibility is the energy use through fuel cells in vehicles using H 2 as fuel free of CO (smaller concentration to 10 ppm). Processes exist for the production of H 2 starting from the methanol and in this work the one was used reformed of methanol with water vapor and oxygen (OSRM) as the main reaction of this work. The primordial objective of this work consists on studying the catalytic properties of the copper (Cu) supported in mixed oxides (ZrO 2 -CeO 2 ) in the reaction of having reformed of methanol with water vapor and oxygen for the production of H 2 . Zirconia is synthesized (ZrO 2 ) and mixed oxides ZrO 2 -CeO 2 (with different relationship Zr/Ce) for the sol-gel method and the one cerium oxide (CeO 2 ) by direct combustion of the cerium nitrate. The oxides were stabilized thermally at 600 C by 5h. The catalysts were prepared by classic impregnation using copper acetate, the nominal concentration was of 3% in weight. The catalysts were roasted at 350 C and later on reduced in flow from H 2 to 350 C for 1h. The characterization of the catalytic materials is carried out through different techniques as: adsorption-desorption of nitrogen to determine the surface area BET, scanning electron microscopy (SEM) to determine the final morphology of the catalysts, X-ray diffraction (XRD) to identify the crystalline phases of the catalytic materials and reduction to programmed temperature (TPR) to evidence the interaction metal-support. The catalytic properties of the catalysts were studied in the reaction CH 3 OH + H 2 O + O 2 , to determine the activity and selectivity. The surface area of the mixed oxides was

  4. Potassium permanganate for mercury vapor environmental control

    Science.gov (United States)

    Kuivinen, D. E.

    1972-01-01

    Potassium permanganate (KMnO4) was evaluated for application in removing mercury vapor from exhaust air systems. The KMnO4 may be used in water solution with a liquid spray scrubber system or as a solid adsorber bed material when impregnated onto a zeolite. Air samples contaminated with as much as 112 mg/cu m of mercury were scrubbed to 0.06mg/cum with the KMnO4-impregnated zeolite (molecular sieve material). The water spray solution of permanganate was also found to be as effective as the impregnated zeolite. The KMnO4-impregnated zeolite was applied as a solid adsorber material to (1) a hardware decontamination system, (2) a model incinerator, and (3) a high vacuum chamber for ion engine testing with mercury as the propellant. A liquid scrubber system was also applied in an incinerator system. Based on the results of these experiments, it is concluded that the use of KMnO4 can be an effective method for controlling noxious mercury vapor.

  5. GOES WATER VAPOR TRANSPORT V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOES Water Vapor Transport CD contains nineteen months of geostationary satellite-derived products from the GOES-8 satellite spanning the 1987-1988 El Nino...

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

    Science.gov (United States)

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

    1995-01-01

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

  7. Vapor compression distiller and membrane technology for water revitalization

    Science.gov (United States)

    Ashida, A.; Mitani, K.; Ebara, K.; Kurokawa, H.; Sawada, I.; Kashiwagi, H.; Tsuji, T.; Hayashi, S.; Otsubo, K.; Nitta, K.

    1987-01-01

    Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied: one is absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation, able to easily produce condensed water under zero gravity, was investigated experimentally and through simulated calculation. The vapor compression distiller was studied experimentally and it offers significant energy savings for evaporation of water.

  8. Water vapor-nitrogen absorption at CO2 laser frequencies

    Science.gov (United States)

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

    1979-01-01

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

  9. Effects of argon and oxygen flow rate on water vapor barrier properties of silicon oxide coatings deposited on polyethylene terephthalate by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Kim, Sung-Ryong; Choudhury, Moinul Haque; Kim, Won-Ho; Kim, Gon-Ho

    2010-01-01

    Plasma polymer coatings were deposited from hexamethyldisiloxane on polyethylene terephthalate (PET) substrates while varying the operating conditions, such as the Ar and O 2 flow rates, at a fixed radio frequency power of 300 W. The water vapor transmission rate (WVTR) of the untreated PET was 54.56 g/m 2 /day and was decreased after depositing the silicon oxide (SiO x ) coatings. The minimum WVTR, 0.47 g/m 2 /day, was observed at Ar and O 2 flow rates of 4 and 20 sccm, respectively, with a coating thickness of 415.44 nm. The intensity of the peaks for the Si-O-Si bending at 800-820 cm -1 and Si-O-Si stretching at 1000-1150 cm -1 varied depending on the Ar and O 2 flow rates. The contact angle of the SiO x coated PET increased as the Ar flow rate was increased from 2 to 8 sccm at a fixed O 2 flow rate of 20 sccm. It decreased gradually as the oxygen flow rate increased from 12 to 28 sccm at a fixed Ar carrier gas flow rate. The examination by atomic force microscopy revealed a correlation of the SiO x morphology and the water vapor barrier performance with the Ar and O 2 flow rates. The roughness of the deposited coatings increased when either the O 2 or Ar flow rate was increased.

  10. Observation of Mountain Lee Waves with MODIS NIR Column Water Vapor

    Science.gov (United States)

    Lyapustin, A.; Alexander, M. J.; Ott, L.; Molod, A.; Holben, B.; Susskind, J.; Wang, Y.

    2014-01-01

    Mountain lee waves have been previously observed in data from the Moderate Resolution Imaging Spectroradiometer (MODIS) "water vapor" 6.7 micrometers channel which has a typical peak sensitivity at 550 hPa in the free troposphere. This paper reports the first observation of mountain waves generated by the Appalachian Mountains in the MODIS total column water vapor (CWV) product derived from near-infrared (NIR) (0.94 micrometers) measurements, which indicate perturbations very close to the surface. The CWV waves are usually observed during spring and late fall or some summer days with low to moderate CWV (below is approx. 2 cm). The observed lee waves display wavelengths from3-4 to 15kmwith an amplitude of variation often comparable to is approx. 50-70% of the total CWV. Since the bulk of atmospheric water vapor is confined to the boundary layer, this indicates that the impact of thesewaves extends deep into the boundary layer, and these may be the lowest level signatures of mountain lee waves presently detected by remote sensing over the land.

  11. Reaction rate constant for uranium in water and water vapor

    Energy Technology Data Exchange (ETDEWEB)

    TRIMBLE, D.J.

    1998-11-09

    The literature on uranium oxidation in water and oxygen free water vapor was reviewed. Arrhenius rate equations were developed from the review data. These data and equations will be used as a baseline from which to compare reaction rates measured for K Basin fuel.

  12. Metalorganic chemical vapor deposition of Er{sub 2}O{sub 3} thin films: Correlation between growth process and film properties

    Energy Technology Data Exchange (ETDEWEB)

    Giangregorio, Maria M. [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM sez. Bari, Via Orabona 4, 70125 Bari (Italy)], E-mail: michelaria.giangregorio@ba.imip.cnr.it; Losurdo, Maria; Sacchetti, Alberto; Capezzuto, Pio; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM sez. Bari, Via Orabona 4, 70125 Bari (Italy)

    2009-02-27

    Er{sub 2}O{sub 3} thin films have been grown by metalorganic chemical vapor deposition (MOCVD) at 600 deg. C on different substrates, including glass, Si (100) and sapphire (0001) using tris(isopropylcyclopentadienyl)erbium and O{sub 2}. The effects of growth parameters such as the substrate, the O{sub 2} plasma activation and the temperature of organometallic precursor injection, on the nucleation/growth kinetics and, consequently, on film properties have been investigated. Specifically, very smooth (111)-oriented Er{sub 2}O{sub 3} thin films (the root mean square roughness is 0.3 nm) are achieved on Si (100), {alpha}-Al{sub 2}O{sub 3} (0001) and amorphous glass by MOCVD. Growth under O{sub 2} remote plasma activation results in an increase in growth rate and in (100)-oriented Er{sub 2}O{sub 3} films with high refractive index and transparency in the visible photon energy range.

  13. The Planck-Benzinger thermal work function in the condensation of water vapor

    Science.gov (United States)

    Chun, Paul W.

    Based on the Planck-Benzinger thermal work function using Chun's method, the innate temperature-invariant enthalpy at 0 K, ?H0(T0), for the condensation of water vapor as well as the dimer, trimer, tetramer, and pentamer form in the vapor phase, was determined to be 0.447 kcal mol-1 for vapor, 1.127 for the dimer, 0.555 for the trimer, 0.236 for the tetramer, and 0.079 kcal mol-1 for the pentamer using ?G(T) data reported by Kell et al. in 1968 and Kell and McLaurin in 1969. These results suggest that the predominant dimeric form is the most stable of these n-mers. Using Nemethy and Scheraga's 1962 data for the Helmholtz free energy of liquid water, the value of ?H0(T0) was determined to be 1.21 kcal mol-1. This is very close to the value for the energy of the hydrogen bond EH of 1.32 kcal mol-1 reported by Nemethy and Scheraga, using statistical thermodynamics. It seems clear that very little energy is required for interconversion between the hypothetical supercooled water vapor and glassy water at 0 K. A hypothetical supercooled water vapor at 0 K is apparently almost as highly associated as glassy water at that temperature, suggesting a dynamic equilibrium between vapor and liquid. This water vapor condensation is highly similar in its thermodynamic behavior to that of sequence-specific pairwise (dipeptide) hydrophobic interaction, except that the negative Gibbs free energy change minimum at ?Ts?, the thermal setpoint for vapor condensation, where T?S = 0, occurs at a considerably lower temperature, 270 K (below 0°C) compared with ?350 K. The temperature of condensation ?Tcond? at which ?G(T) = 0, where water vapor begins to condense, was found to be 383 K. In the case of a sequence-specific pairwise hydrophobic interaction, the melting temperature, ?Tm?, where ?G(Tm) = 0 was found to be 460 K. Only between two temperature limits, ?Th? = 99 K and ?Tcond? = 383 K, where ?G(Tcond) = 0, is the net chemical driving force favorable for polymorphism of glassy water

  14. Ground-based observations of Mars and Venus water vapor during 1972 and 1973

    International Nuclear Information System (INIS)

    Barker, E.S.

    1974-01-01

    The Venus water vapor line at 8197.71 A has been monitored at several positions on the disk of Venus and at phase angles between 22 0 and 91 0 . Variations in the abundance have been found with both position and time. The total two-way transmission has varied from less than 5 to 77 μ of water vapor. Comparisons are made between water vapor abundance, presence of UV features and the CO 2 abundance determined from near simultaneous observations of CO 2 bands at the same position on the disk of Venus. The amount of Martian atmospheric water vapor has been monitored during the past two years at McDonald Observatory using the echelle coude scanner of the 272cm reflector. Two periods of the Martain year have been monitored. The first period was during and after the great 1971 dust storm (Lsub(s)=290 0 to 20 0 or summer in the southern hemisphere). The results obtained are compared to the Mariner 9 IRIS and Mars 3 observations made during the same period. During the second period (Lsub(s)=124 0 to 266 0 ) observations were made to follow the seasonal latitudinal and diurnal changes in the water abundance in the Martian atmosphere. Studies of the latitudinal and diurnal vapor distributions indicate the location of maximum and minimum abundances for this season are positively correlated with surface temperature variations. (Auth.)

  15. NASA Experiment on Tropospheric-Stratospheric Water Vapor Transport in the Intertropical Convergence Zone

    Science.gov (United States)

    Page, William A.

    1982-01-01

    transported somehow through the tropopause, the vapor pressure being controlled by the temperature at the tops of the clouds; the dryness of the stratosphere could be explained if most of the transport occurs in connection with very high clouds in regions with very high and cold tropopause. (3) Cumulo-nimbus anvils act as terrestrial-radiation shields allowing the ice particle temperatures near cloud tops to cool radiatively below the supersaturation point; this cooling would cause a vapor deposition on the ice particles which will settle out and thus act as water scavengers. The experiment was designed to collect information on these detailed physical processes near and above the tropopause in order to assess their importance and the role they play in controlling stratospheric water vapor humidity.

  16. A differential absorption technique to estimate atmospheric total water vapor amounts

    Science.gov (United States)

    Frouin, Robert; Middleton, Elizabeth

    1990-01-01

    Vertically integrated water-vapor amounts can be remotely determined by measuring the solar radiance reflected by the earth's surface with satellites or aircraft-based instruments. The technique is based on the method by Fowle (1912, 1913) and utilizes the 0.940-micron water-vapor band to retrieve total-water-vapor data that is independent of surface reflectance properties and other atmospheric constituents. A channel combination is proposed to provide more accurate results, the SE-590 spectrometer is used to verify the data, and the effects of atmospheric photon backscattering is examined. The spectrometer and radiosonde data confirm the accuracy of using a narrow and a wide channel centered on the same wavelength to determine water vapor amounts. The technique is suitable for cloudless conditions and can contribute to atmospheric corrections of land-surface parameters.

  17. Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region

    Directory of Open Access Journals (Sweden)

    S. T. Akhil Raj

    2018-01-01

    Full Text Available We have investigated the long-term trends in and variabilities of stratospheric ozone, water vapor and temperature over the Indian monsoon region using the long-term data constructed from multi-satellite (Upper Atmosphere Research Satellite (UARS MLS and HALOE, 1993–2005, Aura Microwave Limb Sounder (MLS, 2004–2015, Sounding of the Atmosphere using Broadband Emission Radiometry (SABER, 2002–2015 on board TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics observations covering the period 1993–2015. We have selected two locations, namely, Trivandrum (8.4° N, 76.9° E and New Delhi (28° N, 77° E, covering northern and southern parts of the Indian region. We also used observations from another station, Gadanki (13.5° N, 79.2° E, for comparison. A decreasing trend in ozone associated with NOx chemistry in the tropical middle stratosphere is found, and the trend turned to positive in the upper stratosphere. Temperature shows a cooling trend in the stratosphere, with a maximum around 37 km over Trivandrum (−1.71 ± 0.49 K decade−1 and New Delhi (−1.15 ± 0.55 K decade−1. The observed cooling trend in the stratosphere over Trivandrum and New Delhi is consistent with Gadanki lidar observations during 1998–2011. The water vapor shows a decreasing trend in the lower stratosphere and an increasing trend in the middle and upper stratosphere. A good correlation between N2O and O3 is found in the middle stratosphere (∼ 10 hPa and poor correlation in the lower stratosphere. There is not much regional difference in the water vapor and temperature trends. However, upper stratospheric ozone trends over Trivandrum and New Delhi are different. The trend analysis carried out by varying the initial year has shown significant changes in the estimated trend.

  18. The Zugspitze radiative closure experiment for quantifying water vapor absorption over the terrestrial and solar infrared – Part 3: Quantification of the mid- and near-infrared water vapor continuum in the 2500 to 7800 cm−1 spectral range under atmospheric conditions

    Directory of Open Access Journals (Sweden)

    A. Reichert

    2016-09-01

    Full Text Available We present a first quantification of the near-infrared (NIR water vapor continuum absorption from an atmospheric radiative closure experiment carried out at the Zugspitze (47.42° N, 10.98° E; 2964 m a.s.l.. Continuum quantification is achieved via radiative closure using radiometrically calibrated solar Fourier transform infrared (FTIR absorption spectra covering the 2500 to 7800 cm−1 spectral range. The dry atmospheric conditions at the Zugspitze site (IWV 1.4 to 3.3 mm enable continuum quantification even within water vapor absorption bands, while upper limits for continuum absorption can be provided in the centers of window regions. Throughout 75 % of the 2500 to 7800 cm−1 spectral range, the Zugspitze results agree within our estimated uncertainty with the widely used MT_CKD 2.5.2 model (Mlawer et al., 2012. In the wings of water vapor absorption bands, our measurements indicate about 2–5 times stronger continuum absorption than MT_CKD, namely in the 2800 to 3000 cm−1 and 4100 to 4200 cm−1 spectral ranges. The measurements are consistent with the laboratory measurements of Mondelain et al. (2015, which rely on cavity ring-down spectroscopy (CDRS, and the calorimetric–interferometric measurements of Bicknell et al. (2006. Compared to the recent FTIR laboratory studies of Ptashnik et al. (2012, 2013, our measurements are consistent within the estimated errors throughout most of the spectral range. However, in the wings of water vapor absorption bands our measurements indicate typically 2–3 times weaker continuum absorption under atmospheric conditions, namely in the 3200 to 3400, 4050 to 4200, and 6950 to 7050 cm−1 spectral regions.

  19. Conformal coverage of poly(3,4-ethylenedioxythiophene) films with tunable nanoporosity via oxidative chemical vapor deposition

    NARCIS (Netherlands)

    Im, S.G.; Kusters, D.J.N.; Choi, W.; Baxamusa, S.H.; Sanden, van de M.C.M.; Gleason, K.K.

    2008-01-01

    Novel nanoporous poly(3,4-ethylenedioxythiophene) (PEDOT) films with basalt-like surface morphology are successfully obtained via a one-step, vapor phase process of oxidative chemical vapor deposition (oCVD) by introducing a new oxidant, CuCl2, The substrate temperature of the oCVD process is a

  20. Upper limits for absorption by water vapor in the near-UV

    International Nuclear Information System (INIS)

    Wilson, Eoin M.; Wenger, John C.; Venables, Dean S.

    2016-01-01

    There are few experimental measurements of absorption by water vapor in the near-UV. Here we report the results of spectral measurements of water vapor absorption at ambient temperature and pressure from 325 nm to 420 nm, covering most tropospherically relevant short wavelengths. Spectra were recorded using a broadband optical cavity in the chemically controlled environment of an atmospheric simulation chamber. No absorption attributable to the water monomer (or the dimer) was observed at the 0.5 nm resolution of our system. Our results are consistent with calculated spectra and recent DOAS field observations, but contradict a report of significant water absorption in the near-UV. Based on the detection limit of our instrument, we report upper limits for the water absorption cross section of less than 5×10 −26 cm 2 molecule −1 at our instrument resolution. For a typical, indicative slant column density of 4×10 23 cm 2 , we calculate a maximum optical depth of 0.02 arising from absorption of water vapor in the atmosphere at wavelengths between 340 nm and 420 nm, with slightly higher maximum optical depths below 340 nm. The results of this work, together with recent atmospheric observations and computational results, suggest that water vapor absorption across most of the near-UV is small compared to visible and infrared wavelengths. - Highlights: • The absorption cross section of water vapor was studied from 325 to 420 nm. • The upper limit was 5×10 −26 cm 2 molecule −1 above 340 nm at 0.5 nm resolution. • Our result contradicts a recent report of appreciable absorption by water vapor.

  1. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    Energy Technology Data Exchange (ETDEWEB)

    Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration Environmental Technology Laboratoy, Boulder, CO (United States); Rye, B.J. [Univ. of Colorado, Boulder, CO (United States)

    1996-04-01

    The development and verification of realistic climate model parameterizations for clouds and net radiation balance and the correction of other site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. In this study, we develop system performance models and examine the potential of infrared differential absoroption lidar (DIAL) to determine the concentration of water vapor.

  2. The AquaVIT-1 intercomparison of atmospheric water vapor measurement techniques

    Science.gov (United States)

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

    2014-09-01

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

  3. Synthesis, Crystal Structure and Water Vapor Adsorption Properties of a Porous Supramolecular Architecture

    Directory of Open Access Journals (Sweden)

    Rui Qiao

    2017-10-01

    Full Text Available A new complex, [Cu4(HL4(H2O14] (1, H3L·HCl = 5-((4-carboxypiperidin-1-ylmethylisophthalic acid hydrochloride, has been prepared and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and powder X-ray diffraction (PXRD. The result of the X-ray diffraction analysis reveals that the complex crystallizes in monoclinic, space group C2/c and three unique Cu(II atoms that are connected by partially deprotonated HL2− anion to form a cyclic structure. The rich hydrogen bonding and π-π non-covalent packing interactions extend cyclic units into a three-dimensional (3D supramolecular polymer. Moreover, the thermogravimetric (TG analysis and water vapor adsorption property of 1 were also discussed.

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

    African Journals Online (AJOL)

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

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  6. The SPARC water vapor assessment II: intercomparison of satellite and ground-based microwave measurements

    Science.gov (United States)

    Nedoluha, Gerald E.; Kiefer, Michael; Lossow, Stefan; Gomez, R. Michael; Kämpfer, Niklaus; Lainer, Martin; Forkman, Peter; Christensen, Ole Martin; Oh, Jung Jin; Hartogh, Paul; Anderson, John; Bramstedt, Klaus; Dinelli, Bianca M.; Garcia-Comas, Maya; Hervig, Mark; Murtagh, Donal; Raspollini, Piera; Read, William G.; Rosenlof, Karen; Stiller, Gabriele P.; Walker, Kaley A.

    2017-12-01

    As part of the second SPARC (Stratosphere-troposphere Processes And their Role in Climate) water vapor assessment (WAVAS-II), we present measurements taken from or coincident with seven sites from which ground-based microwave instruments measure water vapor in the middle atmosphere. Six of the ground-based instruments are part of the Network for the Detection of Atmospheric Composition Change (NDACC) and provide datasets that can be used for drift and trend assessment. We compare measurements from these ground-based instruments with satellite datasets that have provided retrievals of water vapor in the lower mesosphere over extended periods since 1996. We first compare biases between the satellite and ground-based instruments from the upper stratosphere to the upper mesosphere. We then show a number of time series comparisons at 0.46 hPa, a level that is sensitive to changes in H2O and CH4 entering the stratosphere but, because almost all CH4 has been oxidized, is relatively insensitive to dynamical variations. Interannual variations and drifts are investigated with respect to both the Aura Microwave Limb Sounder (MLS; from 2004 onwards) and each instrument's climatological mean. We find that the variation in the interannual difference in the mean H2O measured by any two instruments is typically ˜ 1%. Most of the datasets start in or after 2004 and show annual increases in H2O of 0-1 % yr-1. In particular, MLS shows a trend of between 0.5 % yr-1 and 0.7 % yr-1 at the comparison sites. However, the two longest measurement datasets used here, with measurements back to 1996, show much smaller trends of +0.1 % yr-1 (at Mauna Loa, Hawaii) and -0.1 % yr-1 (at Lauder, New Zealand).

  7. The SPARC water vapor assessment II: intercomparison of satellite and ground-based microwave measurements

    Directory of Open Access Journals (Sweden)

    G. E. Nedoluha

    2017-12-01

    Full Text Available As part of the second SPARC (Stratosphere–troposphere Processes And their Role in Climate water vapor assessment (WAVAS-II, we present measurements taken from or coincident with seven sites from which ground-based microwave instruments measure water vapor in the middle atmosphere. Six of the ground-based instruments are part of the Network for the Detection of Atmospheric Composition Change (NDACC and provide datasets that can be used for drift and trend assessment. We compare measurements from these ground-based instruments with satellite datasets that have provided retrievals of water vapor in the lower mesosphere over extended periods since 1996. We first compare biases between the satellite and ground-based instruments from the upper stratosphere to the upper mesosphere. We then show a number of time series comparisons at 0.46 hPa, a level that is sensitive to changes in H2O and CH4 entering the stratosphere but, because almost all CH4 has been oxidized, is relatively insensitive to dynamical variations. Interannual variations and drifts are investigated with respect to both the Aura Microwave Limb Sounder (MLS; from 2004 onwards and each instrument's climatological mean. We find that the variation in the interannual difference in the mean H2O measured by any two instruments is typically  ∼  1%. Most of the datasets start in or after 2004 and show annual increases in H2O of 0–1 % yr−1. In particular, MLS shows a trend of between 0.5 % yr−1 and 0.7 % yr−1 at the comparison sites. However, the two longest measurement datasets used here, with measurements back to 1996, show much smaller trends of +0.1 % yr−1 (at Mauna Loa, Hawaii and −0.1 % yr−1 (at Lauder, New Zealand.

  8. Coupling catalytic hydrolysis and oxidation on Mn/TiO2-Al2O3 for HCN removal

    Science.gov (United States)

    Wang, Langlang; Wang, Xueqian; Cheng, Jinhuan; Ning, Ping; Lin, Yilong

    2018-05-01

    The manganese-modified titania-alumina (Mn/TiO2-Al2O3) catalyst synthesized by sol-gol method was used to remove hydrogen cyanide (HCN) from simulated flue gas. Further, effects of the mass ratios of Ti/Al, Mn loading, calcination temperature, and relative humidity on HCN conversion efficiency and catalytic activity were systematically investigated. The results indicated that the Mn/TiO2-Al2O3 catalyst exhibited significantly enhanced HCN removal efficiency, and the maximum yield of N2 increased to 68.02% without the participation of water vapor. When water vapor was added into the flue gas, the yield of N2 decreased and the formation of NOx was also inhibited. The XRD and XPS results indicated that Mn was mainly present in the form of Mn2+, Mn3+, and Mn4+ on the surface of catalyst and chemisorbed oxygen played a major role in the HCN catalytic oxidation process. The results of DSC-TGA analysis and H2-TPR indicated that the catalyst also exhibited a good thermal and chemical stability. NH3-TPD and CO2-TPD indicated that the surface of the catalyst mainly contained acidic sites. During the reaction, part of NH3 was adsorbed by Brönsted and Lewis acid sites. NH3 adsorbed on Lewis acid sites participated in NH3-SCR, which reduced the amount of NOx produced and resulted in a high N2 yield.

  9. Use of water vapor for suppressing the growth of unstable low-κ interlayer in HfTiO gate-dielectric Ge metal-oxide-semiconductor capacitors with sub-nanometer capacitance equivalent thickness

    International Nuclear Information System (INIS)

    Xu, J.P.; Zou, X.; Lai, P.T.; Li, C.X.; Chan, C.L.

    2009-01-01

    Annealing of high-permittivity HfTiO gate dielectric on Ge substrate in different gases (N 2 , NH 3 , NO and N 2 O) with or without water vapor is investigated. Analysis by transmission electron microscopy indicates that the four wet anneals can greatly suppress the growth of a GeO x interlayer at the dielectric/Ge interface, and thus decrease interface states, oxide charges and gate leakage current. Moreover, compared with the wet N 2 anneal, the wet NH 3 , NO and N 2 O anneals decrease the equivalent permittivity of the gate dielectric due to the growth of a GeO x N y interlayer. Among the eight anneals, the wet N 2 anneal produces the best dielectric performance with an equivalent relative permittivity of 35, capacitance equivalent thickness of 0.81 nm, interface-state density of 6.4 x 10 11 eV -1 cm -2 and gate leakage current of 2.7 x 10 -4 A/cm 2 at V g = 1 V

  10. Evaluation of corrosivity of the vapor-phase environments to sterilized water with chlorine; Enso kei mekkin shorisui no kisho kankyo no fushokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Michio. [Nippon Steel Corp. Yamaguchi (Japan). Technical Development Bureau

    1999-08-15

    Corrosivity of vapor-phase aenvironments in indoor pool, water thank, and water purification plants was investigated. Sodium hypochlorite (NaClO) was used as a sterilizing agent in indoor pool, while chlorine gas was used in water tank and water purification plants. It was found that Cl{sup -} ion were concentrated in the dew formed in the indoor pool. H{sup +} ions as well as Cl{sup -} ions were accumulated in the dew dormed in the water tank ans water purification plants. Thus, the corrosion condition was varied with the type of sterilizing agents used. Through the investigation of water tanl, the relationship between pH and Cl{sup -} ion concentration was given as follow; pH=-1.09-2.19 log [Cl{sup -}] (mol/L). Corrosivity of vapor-phase enviroments in sterilizing water systems would be characterized by the exstence of oxidizing chemical agents such as ClO{sup -} and HClO, the shift of corrosion potenrial of the thin water film, and the accumulation of H{sup +} and/or Cl{sup -} ions in the dew. (author)

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

    Science.gov (United States)

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

    2016-01-01

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

  12. Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth J.

    1994-01-01

    The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

  13. Determination of water vapor and aerosol densities in the tropospheric atmosphere from nitrogen and water vapor raman signals

    CERN Document Server

    Kim, D H; Lee, J M; Yeon, K H; Choi, S C

    1998-01-01

    A Raman lidar system has been developed for the measurement of the water-vapor mixing ratio and the aerosol backscatter and extinction coefficients. To suppress the elastic scattering from the XeCl excimer laser, an acetone edge filter and narrow-band interference filters are used. By using independently calculated backscatter and extinction coefficients, we calculate the lidar ratios (extinction coefficient divided by the backscatter coefficient). The obtained ratios between 30 and 50 sr explain the special characteristics of the aerosol existing in the atmosphere. These ratios are also used as important parameters in the lidar inversion program. We have also obtained the water-vapor mixing ratio and find that big differences exist between the ratios inside the boundary layer and those of other regions.

  14. Bias polarization study of steam electrolysis by composite oxygen electrode Ba0.5Sr0.5Co0.8Fe0.2O3-δ/BaCe0.4Zr0.4Y0.2O3

    Science.gov (United States)

    Yang, Tao; Shaula, Aliaksandr; Pukazhselvan, D.; Ramasamy, Devaraj; Deng, Jiguang; da Silva, E. L.; Duarte, Ricardo; Saraiva, Jorge A.

    2017-12-01

    The polarization behavior of Ba0.5Sr0.5Co0.8Fe0.2O3-δ-BaCe0.4Zr0.4Y0.2O3-δ (BSCF-BCZY) electrode under steam electrolysis conditions was studied in detail. The composite oxygen electrode supported by BCZY electrolyzer has been assessed as a function of temperature (T), water vapor partial pressures (pH2O), and bias polarization voltage for electrodes of comparable microstructure. The Electrochemical impedance spectra show two depressed arcs in general without bias polarization. And the electrode resistance became smaller with the increase of the bias polarization under the same water vapor partial pressures. The total resistance of the electrode was shown to be significantly affected by temperature, with the same level of pH2O and bias polarization voltage. This result highlights BSCF-BCZY as an effective oxygen electrode under moderate polarization and pH2O conditions.

  15. Surface characterization of U(AlxSi1-x)3 alloy and its interaction with O2 and H2O, at room temperature

    Science.gov (United States)

    Matmor, M.; Cohen, S.; Rafailov, G.; Vaknin, M.; Shamir, N.; Gouder, T.; Zalkind, S.

    2018-02-01

    Surface characterization and the interactions of U(AlxSi1-x)3 alloy (x = 0.57) with oxygen and water vapor were studied, utilizing X-Ray Photoelectron Spectroscopy and Direct Recoil Spectrometry, at room temperature. The U 4f spectrum of U(AlxSi1-x)3 alloy exhibits weak correlation satellites, suggesting an itinerant description of the U 5f states for this compound. The Al and Si 2p lines are chemically shifted to lower binding energies. Exposing the alloy to oxygen and water vapor results in oxidation of mainly the uranium and aluminum components, while silicon is only slightly oxidized. Oxygen was found to be a stronger oxidizer than water vapor and the trend is consistent with the more negative enthalpies of formation of metal oxides produced by the O2 reaction, as compared to H2O. During oxygen exposure, fast oxidation occurs by oxide islands nucleation and lateral growth, followed by oxidation of the sub-surface, up to ∼4 nm, at 1000 L exposure. Water initially reacts with the surface by full dissociation and oxide islands formation, which is then covered by hydroxides. Only a minor increase in the oxide thickness of up to ∼2.5 nm, was observed after coalescence.

  16. A Plant-Based Proxy for the Oxygen Isotope Ratio of Atmospheric Water Vapor

    Science.gov (United States)

    Helliker, B.

    2007-12-01

    Atmospheric water vapor is a major component of the global hydrological cycle, but the isotopic balance of vapor is largely unknown. It is shown here that the oxygen isotope ratio of leaf water in the epiphytic Crassulacean acid metabolism (CAM) plant Tillandsia usneoides (Spanish Moss) is controlled by the oxygen isotope ratio of atmospheric water vapor in both field and lab studies. Assuming that the leaf-water isotopic signature (and hence the atmospheric water vapor signature) is recorded in plant organic material, the atmospheric water vapor oxygen isotope ratios for Miami, Florida (USA) were reconstructed for several years from 1878 to 2005 using contemporary and herbarium specimens. T. usneoides ranges from Virginia, USA southwards through the tropics to Argentina, and the CAM epiphytic lifeform is widespread in other species. Therefore, epiphytes may be used to reconstruct the isotope ratio of atmospheric water for spatial scales that span over 60° of latitude and temporal scales that cover the last century of global temperature increase.

  17. Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2005-01-01

    Full Text Available A transient model simulation of the 40-year time period 1960 to 1999 with the coupled climate-chemistry model (CCM ECHAM4.L39(DLR/CHEM shows a stratospheric water vapor increase over the last two decades of 0.7 ppmv and, additionally, a short-term increase after major volcanic eruptions. Furthermore, a long-term decrease in global total ozone as well as a short-term ozone decline in the tropics after volcanic eruptions are modeled. In order to understand the resulting effects of the water vapor changes on lower stratospheric ozone chemistry, different perturbation simulations were performed with the CCM ECHAM4.L39(DLR/CHEM feeding the water vapor perturbations only to the chemistry part. Two different long-term perturbations of lower stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months were applied. An additional stratospheric water vapor amount of 1 ppmv results in a 5–10% OH increase in the tropical lower stratosphere between 100 and 30 hPa. As a direct consequence of the OH increase the ozone destruction by the HOx cycle becomes 6.4% more effective. Coupling processes between the HOx-family and the NOx/ClOx-family also affect the ozone destruction by other catalytic reaction cycles. The NOx cycle becomes 1.6% less effective, whereas the effectiveness of the ClOx cycle is again slightly enhanced. A long-term water vapor increase does not only affect gas-phase chemistry, but also heterogeneous ozone chemistry in polar regions. The model results indicate an enhanced heterogeneous ozone depletion during antarctic spring due to a longer PSC existence period. In contrast, PSC formation in the northern hemisphere polar vortex and therefore heterogeneous ozone depletion during arctic spring are not affected by the water vapor increase, because of the less PSC activity. Finally, this study shows that 10% of the global total ozone decline in the transient model run

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

    Science.gov (United States)

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

    1987-01-01

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

  19. Material gap membrane distillation: A new design for water vapor flux enhancement

    KAUST Repository

    Francis, Lijo

    2013-08-19

    A new module design for membrane distillation, namely material gap membrane distillation (MGMD), for seawater desalination has been proposed and successfully tested. It has been observed that employing appropriate materials between the membrane and the condensation plate in an air gap membrane distillation (AGMD) module enhanced the water vapor flux significantly. An increase in the water vapor flux of about 200-800% was observed by filling the gap with sand and DI water at various feed water temperatures. However, insulating materials such as polypropylene and polyurethane have no effect on the water vapor flux. The influence of material thickness and characteristics has also been investigated in this study. An increase in the water gap width from 9. mm to 13. mm increases the water vapor flux. An investigation on an AGMD and MGMD performance comparison, carried out using two different commercial membranes provided by different manufacturers, is also reported in this paper. © 2013 Elsevier B.V.

  20. Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based...

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

    Science.gov (United States)

    Tucker, George F.

    1995-01-01

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

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

    International Nuclear Information System (INIS)

    Dan, Ho Jin; Lee, Joon Sik

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Ho Jin; Lee, Joon Sik [Seoul National University, Seoul (Korea, Republic of)

    2016-03-15

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

  4. Synthesis of highly efficient Mn{sub 2}O{sub 3} catalysts for CO oxidation derived from Mn-MIL-100

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaodong, E-mail: fatzhxd@126.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Li, Hongxin; Hou, Fulin; Yang, Yang; Dong, Han; Liu, Ning [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China); Wang, Yuxin [Institute of Applied Biotechnology, Taizhou Vocation & Technical College, Taizhou, Zhejiang 318000 (China); Cui, Lifeng, E-mail: lifeng.cui@gmail.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2017-07-31

    Highlights: • The morphology of porous Mn{sub 2}O{sub 3} cubes was inherited from Mn-MIL-100 template. • Mn{sub 2}O{sub 3} obtained at calcined temperature of 700 °C displayed high activity. • Enhanced activity is attributed to surface active oxygen, and reduction behavior. - Abstract: In this work, metal-organic frameworks (MOFs) Mn-MIL-100 were first prepared, which were next used as templates to obtain the irregular porous Mn{sub 2}O{sub 3} cubes through calcination with air at different temperature. The catalysts were characterized by N{sub 2} adsorption-desorption, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), H{sub 2}-temperature program reduction (H{sub 2}-TPR) and X-ray photoelectron spectroscopic (XPS). The catalytic activity for CO oxidation over Mn{sub 2}O{sub 3} catalysts was investigated. It was found that calcination temperature had a strong effect on the structure and catalytic activity of Mn{sub 2}O{sub 3} catalyst. Mn{sub 2}O{sub 3} catalyst obtained by calcined at 700 °C (Mn{sub 2}O{sub 3}-700) showed a smaller specific surface area, but displayed a high catalytic activity and excellent stability with a complete CO conversion temperature (T{sub 98}) of 240 °C, which was attributed to the unique structure, a high quantity of surface active oxygen species, smaller particle size, oxygen vacancies and good low temperature reduction behavior. The effect of water vapor on catalytic activity was also examined. The introduction of water vapor to the feedstock induced a positive effect on CO oxidation over Mn{sub 2}O{sub 3}-700 catalyst. Furthermore, no obvious drop is observed in activity over catalysts even in the presence of water vapor during 48 h.

  5. The Intrinsic Variability in the Water Vapor Saturation Ratio due to Turbulence

    Science.gov (United States)

    Anderson, J. C.; Cantrell, W. H.; Chandrakar, K. K.; Kostinski, A. B.; Niedermeier, D.; Shaw, R. A.

    2017-12-01

    In the atmosphere, the concentration of water vapor plays an important role in Earth's weather and climate. The mean concentration of water vapor is key to its efficiency as a greenhouse gas; the fluctuations about the mean are important for heat fluxes near the surface of earth. In boundary layer clouds, fluctuations in the water vapor concentration are linked to turbulence. Conditions representative of boundary layer clouds are simulated in Michigan Tech's multiphase, turbulent reaction chamber, the ∏ chamber, where the boundary conditions are controlled and repeatable. Measurements for temperature and water vapor concentration were recorded under forced Rayleigh-Bénard convection. As expected, the distributions for temperature and water vapor concentration broaden as the turbulence becomes more vigorous. From these two measurements the saturation ratio can be calculated. The fluctuations in the water vapor concentration are more important to the variability in the saturation ratio than fluctuations in temperature. In a cloud, these fluctuations in the saturation ratio can result in some cloud droplets experiencing much higher supersaturations. Those "lucky" droplets grow by condensation at a faster rate than other cloud droplets. The difference in the droplet growth rate could contribute to a broadened droplet distribution, which leads to the onset of collision-coalescence. With more intense turbulence these effect will become more pronounced as the fluctuations about the mean saturation ratio become more pronounced.

  6. Effect of metabolic gases and water vapor, perfluorocarbon emulsions, and nitric oxide on tissue bubbles during decompression sickness.

    Science.gov (United States)

    Randsøe, Thomas

    2016-05-01

    In aviation and diving, fast decrease in ambient pressure, such as during accidental loss of cabin pressure or when a diver decompresses too fast to sea level, may cause nitrogen (N2) bubble formation in blood and tissue resulting in decompression sickness (DCS). Conventional treatment of DCS is oxygen (O2) breathing combined with recompression.  However, bubble kinetic models suggest, that metabolic gases, i.e. O2 and carbon dioxide (CO2), and water vapor contribute significantly to DCS bubble volume and growth at hypobaric altitude exposures. Further, perfluorocarbon emulsions (PFC) and nitric oxide (NO) donors have, on an experimental basis, demonstrated therapeutic properties both as treatment and prophylactic intervention against DCS. The effect was ascribed to solubility of respiratory gases in PFC, plausible NO elicited nuclei demise and/or N2 washout through enhanced blood flow rate. Accordingly, by means of monitoring injected bubbles in exposed adipose tissue or measurements of spinal evoked potentials (SEPs) in anaesthetized rats, the aim of this study was to: 1) evaluate the contribution of metabolic gases and water vapor to bubble volume at different barometrical altitude exposures, 2) clarify the O2 contribution and N2 solubility from bubbles during administration of PFC at normo- and hypobaric conditions and, 3) test the effect of different NO donors on SEPs during DCS upon a hyperbaric air dive and, to study the influence of  NO on tissue bubbles at high altitude exposures. The results support the bubble kinetic models and indicate that metabolic gases and water vapor contribute significantly to bubble volume at 25 kPa (~10,376 m above sea level) and constitute a threshold for bubble stabilization or decay at the interval of 47-36 kPa (~6,036 and ~7,920 m above sea level). The effect of the metabolic gases and water vapor seemed to compromise the therapeutic properties of both PFC and NO at altitude, while PFC significantly increased bubble

  7. Muonium formation and the 'missing fraction' in vapors

    International Nuclear Information System (INIS)

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

    1983-06-01

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

  8. Effects of oxidation-nitridation in the presence of water vapor on ASTM A335 P92 steel using SEM-EDS and XPS characterization techniques

    Science.gov (United States)

    Orozco, J. C.; Kafarov, V.; Y Peña, D.; Alviz, A.

    2017-12-01

    This research studies the physical and chemical changes in steel ASTM A335 P92, produced from a typical refinery corrosion environment. The environment evaluated was oxidation-nitridation with the presence of water vapor. In this study five (5) exposure times were selected: 1, 20, 50, 100 and 200 hours; As well as two (2) analysis temperatures: 450 and 550°C. The working pressure used was one (1) atmosphere. Bearing in mind the kinetic study, the behaviour shown in ASTM A335 P92 steel describes an accelerated growth until 50 hours, after this time growth is less. For the tests carried out at 450°C, the kinetic constant was 2x10-8g2mm-4h-1, as well as for 550°C the calculated kinetic constant was 3.1×10-7g2mm-4h-1 through the SEM-EDS characterization techniques, it was possible to appreciate a good adhesion and homogeneity of the layers formed on the metal matrix until a time of exposure of 100 hours at 450 and 550°C, different from that evidenced to 200 hours of exposure where the layer formed near to the substrate showed detachment, this is attributed to the formation of hydroxides product of water vapor. Among the results obtained are the elemental composition, the presence of nitrides such as Si3N4, also NSiO2 and NSi2O, molybdenum oxides: MoO2 and MoO3 and iron oxides: FeO and Fe2O3 can be evidenced.

  9. Airborne differential absorption lidar system for water vapor investigations

    Science.gov (United States)

    Browell, E. V.; Carter, A. F.; Wilkerson, T. D.

    1981-01-01

    Range-resolved water vapor measurements using the differential-absorption lidar (DIAL) technique is described in detail. The system uses two independently tunable optically pumped lasers operating in the near infrared with laser pulses of less than 100 microseconds separation, to minimize concentration errors caused by atmospheric scattering. Water vapor concentration profiles are calculated for each measurement by a minicomputer, in real time. The work is needed in the study of atmospheric motion and thermodynamics as well as in forestry and agriculture problems.

  10. Application of an automatic cloud tracking technique to Meteosat water vapor and infrared observations

    Science.gov (United States)

    Endlich, R. M.; Wolf, D. E.

    1980-01-01

    The automatic cloud tracking system was applied to METEOSAT 6.7 micrometers water vapor measurements to learn whether the system can track the motions of water vapor patterns. Data for the midlatitudes, subtropics, and tropics were selected from a sequence of METEOSAT pictures for 25 April 1978. Trackable features in the water vapor patterns were identified using a clustering technique and the features were tracked by two different methods. In flat (low contrast) water vapor fields, the automatic motion computations were not reliable, but in areas where the water vapor fields contained small scale structure (such as in the vicinity of active weather phenomena) the computations were successful. Cloud motions were computed using METEOSAT infrared observations (including tropical convective systems and midlatitude jet stream cirrus).

  11. GPS Water Vapor Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters

    Science.gov (United States)

    Champollion, C.; Masson, F.; Bock, O.; Bouin, M.; Walpersdorf, A.; Doerflinger, E.; van Baelen, J.; Brenot, H.

    2003-12-01

    The Global Positioning System (GPS) is now a common technique for the retrieval of zenithal integrated water vapor (IWV). Further applications in meteorology need also slant integrated water vapor (SIWV) which allow to precisely define the high variability of tropospheric water vapor at different temporal and spatial scales. Only precise estimations of IWV and horizontal gradients allow the estimation of accurate SIWV. We present studies developed to improve the estimation of tropospheric water vapor from GPS data. Results are obtained from several field experiments (MAP, ESCOMPTE, OHM-CV, IHOP, .). First IWV are estimated using different GPS processing strategies and results are compared to radiosondes. The role of the reference frame and the a priori constraints on the coordinates of the fiducial and local stations is generally underestimated. It seems to be of first order in the estimation of the IWV. Second we validate the estimated horizontal gradients comparing zenith delay gradients and single site gradients. IWV, gradients and post-fit residuals are used to construct slant integrated water delays. Validation of the SIWV is under progress comparing GPS SIWV, Lidar measurements and high resolution meteorological models (Meso-NH). A careful analysis of the post-fit residuals is needed to separate tropospheric signal from multipaths. The slant tropospheric delays are used to study the 3D heterogeneity of the troposphere. We develop a tomographic software to model the three-dimensional distribution of the tropospheric water vapor from GPS data. The software is applied to the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers operated in southern France. Three inversions have been successfully compared to three successive radiosonde launches. Good resolution is obtained up to heights of 3000 m.

  12. Molybdenum Doped SnO2 Thin Films as a Methanol Vapor Sensor

    Directory of Open Access Journals (Sweden)

    Patil Shriram B.

    2013-02-01

    Full Text Available The molybdenum doped SnO2 thin films were synthesized by conventional spray pyrolysis route and has been investigated for the methanol vapor sensing. The structural and elemental composition analysis of thin films was carried out by X- ray diffraction and Scanning Electron Microscopy (SEM and Energy Dispersive X-ray spectroscopy (EDAX.The XRD spectrum revealed that the thin films have the polycrystalline nature with a mixed phase comprising of SnO2 and MoO3. The scanning Electron Microscopy (SEM clears that the surface morphology observed to be granular, uniformly covering the entire surface area of the thin film. The methanol vapor sensing studies were performed in dry air at the different temperatures. The influence of the concentration of Molybdenum and operating temperature on the sensor performance has been investigated.

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

    Data.gov (United States)

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

  14. Atmospheric pre-corrected differential absorption techniques to retrieve columnar water vapor: Application to AVIRIS 91/95 data

    Energy Technology Data Exchange (ETDEWEB)

    Schlaepfer, D. [Univ. of Zuerich (Switzerland). Dept. of Geography; Borel, C.C. [Los Alamos National Lab., NM (United States); Keller, J. [Paul Scherrer Institut, Villigen (Switzerland)] [and others

    1996-03-01

    Water vapor is one of the main forces for weather development as well as for mesoscale air transport processes. The monitoring of water vapor is therefore an important aim in remote sensing of the atmosphere. Current operational systems for water vapor detection use primarily the emission in the thermal infrared (AVHRR, GOES, ATSR, Meteosat) or in the microwave radiation bands (DMSP). The disadvantage of current satellite systems is either a coarse spatial (horizontal) resolution ranging from one to tens of kilometers or a limited insight into the lower atmosphere. Imaging spectrometry on the other hand measures total column water vapor contents at a high spatial horizontal resolution and has therefore the potential of filling these gaps. The sensors of the AVIRIS instrument are capable of acquiring hyperspectral data in 224 bands located in the visible and near infrared at 10 run resolution. This data includes information on constituents of the earth`s surface as well as of the atmosphere. The optical measurement of water vapor can be performed using sensor channels located in bands or lines of the absorption spectrum. The AVIRIS sensor has been used to retrieve water vapor and with less accuracy carbon dioxide, oxygen and ozone. To retrieve the water vapor amount, the so called differential absorption technique has been applied. The goal of this technique is to eliminate background factors by taking a ratio between channels within the absorption band and others besides the band. Various rationing methods on the basis of different channels and calculation techniques were developed. The influence of a trace gas of interest on the radiance at the sensor level is usually simulated by using radiative transfer codes. In this study, spectral transmittance and radiance are calculated by MODTRAN3 simulations with the new DISORT option. This work testS the best performing differential absorption techniques for imaging spectrometry of tropospheric water vapor.

  15. The influence of water vapor on atmospheric exchange measurements with an ICOS* based Laser absorption analyzer

    Science.gov (United States)

    Bunk, Rüdiger; Quan, Zhi; Wandel, Matthias; Yi, Zhigang; Bozem, Heiko; Kesselmeier, Jürgen

    2014-05-01

    Carbonyl sulfide and carbon monoxide are both atmospheric trace gases of high interest. Recent advances in the field of spectroscopy have enabled instruments that measure the concentration of the above and other trace gases very fast and with good precision. Increasing the effective path length by reflecting the light between two mirrors in a cavity, these instruments reach impressive sensitivities. Often it is possible to measure the concentration of more than one trace gas at the same time. The OCS/CO2 Analyzer by LGR (Los Gatos Research, Inc.) measures the concentration of water vapor [H2O], carbonyl sulfide [COS], carbon dioxide [CO2] and carbon monoxide [CO] simultaneously. For that the cavity is saturated with light, than the attenuation of light is measured as in standard absorption spectroscopy. The instrument proved to be very fast with good precision and to be able to detect even very low concentrations, especially for COS (as low as 30ppt in the case of COS). However, we observed a rather strong cross sensitivity to water vapor. Altering the water vapor content of the sampled air with two different methods led to a change in the perceived concentration of COS, CO and CO2. This proved especially problematic for enclosure (cuvette) measurements, where the concentrations of one of the above species in an empty cuvette are compared to the concentration of another cuvette containing a plant whose exchange of trace gases with the atmosphere is of interest. There, the plants transpiration leads to a large difference in water vapor content between the cuvettes and that in turn produces artifacts in the concentration differences between the cuvettes for the other above mentioned trace gases. For CO, simultaneous measurement with a UV-Emission Analyzer (AL 5002, Aerolaser) and the COS/CO Analyzer showed good agreement of perceived concentrations as long as the sample gas was dry and an increasing difference in perceived concentration when the sample gas was

  16. Tritiated water vapor in the surface air at Tokyo

    International Nuclear Information System (INIS)

    Inoue, Hisayuki; Katsuragi, Yukio; Shigehara, Koji

    1984-01-01

    Tritium concentration in water vapor in the air near the surface and in the precipitation at Tokyo was measured during the period from 9 August to 20 November in 1974. From August to the middle of October, tritium mixing ratios in the surface air had relatively higher values except those in air masses which were associated with a typhoon. The mixing ratios of tritium in the air decreased abruptly at the middle of October, which indicates the decrease of tritium influx from aloft. These data exhibit the salient feature that variations in tritium concentration in TR are linear to the reciprocal of the content of water vapor during each period. Tritium concentrations in vapor and rain water collected simultaneously show nearly equal values. One of the reasons for the good correlation of tritium concentration between falling drops and ambient air is considered to be the result of the rapid isotopic exchange. (author)

  17. Temperature Dependences of Mechanisms Responsible for the Water-Vapor Continuum Absorption

    Science.gov (United States)

    Ma, Qiancheng

    2014-01-01

    The water-vapor continuum absorption plays an important role in the radiative balance in the Earth's atmosphere. It has been experimentally shown that for ambient atmospheric conditions, the continuum absorption scales quadratically with the H2O number density and has a strong, negative temperature dependence (T dependence). Over the years, there have been three different theoretical mechanisms postulated: far-wings of allowed transition lines, water dimers, and collision-induced absorption. The first mechanism proposed was the accumulation of absorptions from the far-wings of the strong allowed transition lines. Later, absorption by water dimers was proposed, and this mechanism provides a qualitative explanation for the continuum characters mentioned above. Despite the improvements in experimental data, at present there is no consensus on which mechanism is primarily responsible for the continuum absorption.

  18. Low-temperature growth of highly crystalline β-Ga2O3 nanowires by solid-source chemical vapor deposition.

    Science.gov (United States)

    Han, Ning; Wang, Fengyun; Yang, Zaixing; Yip, SenPo; Dong, Guofa; Lin, Hao; Fang, Ming; Hung, TakFu; Ho, Johnny C

    2014-01-01

    Growing Ga2O3 dielectric materials at a moderately low temperature is important for the further development of high-mobility III-V semiconductor-based nanoelectronics. Here, β-Ga2O3 nanowires are successfully synthesized at a relatively low temperature of 610°C by solid-source chemical vapor deposition employing GaAs powders as the source material, which is in a distinct contrast to the typical synthesis temperature of above 1,000°C as reported by other methods. In this work, the prepared β-Ga2O3 nanowires are mainly composed of Ga and O elements with an atomic ratio of approximately 2:3. Importantly, they are highly crystalline in the monoclinic structure with varied growth orientations in low-index planes. The bandgap of the β-Ga2O3 nanowires is determined to be 251 nm (approximately 4.94 eV), in good accordance with the literature. Also, electrical characterization reveals that the individual nanowire has a resistivity of up to 8.5 × 10(7) Ω cm, when fabricated in the configuration of parallel arrays, further indicating the promise of growing these highly insulating Ga2O3 materials in this III-V nanowire-compatible growth condition. 77.55.D; 61.46.Km; 78.40.Fy.

  19. Effect of phase interaction on catalytic CO oxidation over the SnO{sub 2}/Al{sub 2}O{sub 3} model catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Shujing [Collaborative Innovation Center of Chemical Science & Engineering (Tianjin), Tianjin Key Laboratory of Applied Catalysis Science & Technology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300354 (China); The Institute of Seawater Desalination and Miltipurpose Utilization, State Oceanic Administration, Tianjin 300192 (China); Bai, Xueqin; Li, Jing; Liu, Cheng; Ding, Tong; Tian, Ye; Liu, Chang [Collaborative Innovation Center of Chemical Science & Engineering (Tianjin), Tianjin Key Laboratory of Applied Catalysis Science & Technology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300354 (China); Xian, Hui [Tianjin Polytechnic University, School of Computer Science & Software Engineering, Tianjin 300387 (China); Mi, Wenbo [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Faculty of Science, Tianjin University, Tianjin 300354 (China); Li, Xingang, E-mail: xingang_li@tju.edu.cn [Collaborative Innovation Center of Chemical Science & Engineering (Tianjin), Tianjin Key Laboratory of Applied Catalysis Science & Technology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300354 (China)

    2017-04-30

    Highlights: • Activity for CO oxidation is greatly enhanced by interaction between SnO{sub 2} and Al{sub 2}O{sub 3}. • Interaction between SnO{sub 2} and Al{sub 2}O{sub 3} phases can generate oxygen vacancies. • Oxygen vacancies play an import role for catalytic CO oxidation. • Sn{sup 4+} cations are the effective sites for catalytic CO oxidation. • Langmuir-Hinshelwood model is preferred for catalytic CO oxidation. - Abstract: We investigated the catalytic CO oxidation over the SnO{sub 2}/Al{sub 2}O{sub 3} model catalysts. Our results show that interaction between the Al{sub 2}O{sub 3} and SnO{sub 2} phases results in the significantly improved catalytic activity because of the formation of the oxygen vacancies. The oxygen storage capacity of the SnO{sub 2}/Al{sub 2}O{sub 3} catalyst prepared by the physically mixed method is nearly two times higher than that of the SnO{sub 2}, which probably results from the change of electron concentration on the interface of the SnO{sub 2} and Al{sub 2}O{sub 3} phases. Introducing water vapor to the feeding gas would a little decrease the activity of the catalysts, but the reaction rate could completely recover after removal of water vapor. The kinetics results suggest that the surface Sn{sup 4+} cations are effective CO adsorptive sites, and the surface adsorbed oxygen plays an important role upon CO oxidation. The reaction pathways upon the SnO{sub 2}-based catalysts for CO oxidation follow the Langmuir-Hinshelwood model.

  20. The measurement of water vapor permeability of glove materials using dilute tritiated water

    International Nuclear Information System (INIS)

    Doughty, D.H.

    1982-01-01

    As fusion technology progresses, there will be an increasing need to handle tritium and tritiated compounds. Protective clothing, especially drybox gloves, must be an effective barrier to minimize worker exposure. The water vapor permeability of glove materials and finished glove constructions is a crucial property of drybox gloves and is not sufficiently well characterized. We have built an apparatus that measures water vapor permeability of elastomers using dilute tritiated water. The technique is more sensitive than other methods currently available and allows us to make measurements on materials and under conditions previously inaccessible. In particular, we present results on laminated drybox gloves for which data is not currently available. (orig.)

  1. Quality and Control of Water Vapor Winds

    Science.gov (United States)

    Jedlovec, Gary J.; Atkinson, Robert J.

    1996-01-01

    Water vapor imagery from the geostationary satellites such as GOES, Meteosat, and GMS provides synoptic views of dynamical events on a continual basis. Because the imagery represents a non-linear combination of mid- and upper-tropospheric thermodynamic parameters (three-dimensional variations in temperature and humidity), video loops of these image products provide enlightening views of regional flow fields, the movement of tropical and extratropical storm systems, the transfer of moisture between hemispheres and from the tropics to the mid- latitudes, and the dominance of high pressure systems over particular regions of the Earth. Despite the obvious larger scale features, the water vapor imagery contains significant image variability down to the single 8 km GOES pixel. These features can be quantitatively identified and tracked from one time to the next using various image processing techniques. Merrill et al. (1991), Hayden and Schmidt (1992), and Laurent (1993) have documented the operational procedures and capabilities of NOAA and ESOC to produce cloud and water vapor winds. These techniques employ standard correlation and template matching approaches to wind tracking and use qualitative and quantitative procedures to eliminate bad wind vectors from the wind data set. Techniques have also been developed to improve the quality of the operational winds though robust editing procedures (Hayden and Veldon 1991). These quality and control approaches have limitations, are often subjective, and constrain wind variability to be consistent with model derived wind fields. This paper describes research focused on the refinement of objective quality and control parameters for water vapor wind vector data sets. New quality and control measures are developed and employed to provide a more robust wind data set for climate analysis, data assimilation studies, as well as operational weather forecasting. The parameters are applicable to cloud-tracked winds as well with minor

  2. Effects of 1997-1998 El Nino on Tropospheric Ozone and Water Vapor

    Science.gov (United States)

    Chandra, S.; Ziemke, J. R.; Min, W.; Read, W. G.

    1998-01-01

    This paper analyzes the impact of the 1997-1998 El Nino on tropospheric column ozone and tropospheric water vapor derived respectively from the Total Ozone Mapping Spectrometer (TOMS) on Earth Probe and the Microwave Limb Scanning instrument on the Upper Atmosphere Research Satellite. The 1997-1998 El Nino, characterized by an anomalous increase in sea-surface temperature (SST) across the eastern and central tropical Pacific Ocean, is one of the strongest El Nino Southern Oscillation (ENSO) events of the century, comparable in magnitude to the 1982-1983 episode. The major impact of the SST change has been the shift in the convection pattern from the western to the eastern Pacific affecting the response of rain-producing cumulonimbus. As a result, there has been a significant increase in rainfall over the eastern Pacific and a decrease over the western Pacific and Indonesia. The dryness in the Indonesian region has contributed to large-scale burning by uncontrolled wildfires in the tropical rainforests of Sumatra and Borneo. Our study shows that tropospheric column ozone decreased by 4-8 Dobson units (DU) in the eastern Pacific and increased by about 10-20 DU in the western Pacific largely as a result of the eastward shift of the tropical convective activity as inferred from National Oceanic and Atmospheric Administration (NOAA) outgoing longwave radiation (OLR) data. The effect of this shift is also evident in the upper tropospheric water vapor mixing ratio which varies inversely as ozone (O3). These conclusions are qualitatively consistent with the changes in atmospheric circulation derived from zonal and vertical wind data obtained from the Goddard Earth Observing System data assimilation analyses. The changes in tropospheric column O3 during the course of the 1997-1998 El Nino appear to be caused by a combination of large-scale circulation processes associated with the shift in the tropical convection pattern and surface/boundary layer processes associated with

  3. Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup

    2012-01-01

    This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed....... A long-term durability test of around 1250 h was performed, in which the concentrations of methanol-water vapor mixture in the anode feed gas were varied. The fuel cell showed a continuous performance decay in the presence of vapor mixtures of methanol and water of 5% and 8% by volume in anode feed...

  4. Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

    Science.gov (United States)

    McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; Bender, Steve; Lemmon, Mark; Wiens, Roger C.; Maurice, Sylvestre; Gasnault, Olivier; Lasue, Jeremie; Meslin, Pierre-Yves; Harri, Ari-Matti; Genzer, Maria; Kemppinen, Osku; Martínez, Germán M.; DeFlores, Lauren; Blaney, Diana; Johnson, Jeffrey R.; Bell, James F.

    2018-06-01

    We derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 Ls = 291° (March 30, 2013) to Mars Year 33 Ls= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model, using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO2 absorptions and the known CO2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large scale circulations and thus

  5. Characterization of Cr2O3 thin films obtained by chemical vapor deposition

    International Nuclear Information System (INIS)

    Pillis, M.F.; Galego, E.; Serna, M.M.; Correa, O.V.; Ramanathan, L.V.; Franco, A.C.

    2010-01-01

    The goal of this work was the synthesis and characterization of Cr 2 O 3 thin films, obtained by chemical vapor deposition, using chromium acetylacetonate as chromium precursor. The growth of the films was carried out in a conventional horizontal MOCVD equipment, under pressures varying from 2 to 10 mbar, and temperature of 600 deg C. It was observed that the growth of the films only occurs when oxygen is present in the atmosphere. Under growth pressures of 2 and 5 mbar the growth takes place but under 10 mbar of pressure the precursor is dragged and the growth does not occur. The characterization of the films was performed by using scanning electron microscopy and X-ray diffraction. The films presented a columnar structure, and thickness varying from 40 to 250 nm. The influence of some process parameters is discussed. (author)

  6. Use of water vapor for suppressing the growth of unstable low-{kappa} interlayer in HfTiO gate-dielectric Ge metal-oxide-semiconductor capacitors with sub-nanometer capacitance equivalent thickness

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.P. [Department of Electronic Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074 (China); Zou, X. [School of Electromachine and Architecture Engineering, Jianghan University, Wuhan, 430056 (China); Lai, P.T. [Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)], E-mail: laip@eee.hku.hk; Li, C.X.; Chan, C.L. [Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)

    2009-03-02

    Annealing of high-permittivity HfTiO gate dielectric on Ge substrate in different gases (N{sub 2}, NH{sub 3}, NO and N{sub 2}O) with or without water vapor is investigated. Analysis by transmission electron microscopy indicates that the four wet anneals can greatly suppress the growth of a GeO{sub x} interlayer at the dielectric/Ge interface, and thus decrease interface states, oxide charges and gate leakage current. Moreover, compared with the wet N{sub 2} anneal, the wet NH{sub 3}, NO and N{sub 2}O anneals decrease the equivalent permittivity of the gate dielectric due to the growth of a GeO{sub x}N{sub y} interlayer. Among the eight anneals, the wet N{sub 2} anneal produces the best dielectric performance with an equivalent relative permittivity of 35, capacitance equivalent thickness of 0.81 nm, interface-state density of 6.4 x 10{sup 11} eV{sup -1} cm{sup -2} and gate leakage current of 2.7 x 10{sup -4} A/cm{sup 2} at V{sub g} = 1 V.

  7. In-situ water vaporization improves bitumen production during electrothermal processes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. [Calgary Univ., AB (Canada); McGee, B. [E-T Energy, Calgary, AB (Canada); Kantzas, A. [Calgary Univ., AB (Canada). Tomographic Imaging and Porous Media Laboratory

    2008-10-15

    Electro-thermal processes are now being considered as an alternative or complementary process to steam injection processes. This study used an in situ vaporized water process to optimize electrothermal processes for steam injection enhanced oil recovery (EOR). A simulation tool was used to model electro-thermal processes in an Athabasca oil sands reservoir. Incremental oil recovery was estimated based on a 3-block conceptual model. A field scale model was then used to investigate the effects of electrode spacing, water injection rates, and electrical heating rates on bitumen recovery. Results of the simulation studies were then analyzed using a statistical tool in order to determine optimal conditions for maximizing bitumen production. Results of the study showed that incremental recovery using the water vaporization technique resulted in oil recovery rates of 25 per cent original oil in place (OOIP). Sensitivity analyses showed that medium electrical heating rates, low water injection rates, and small spacings between electrodes maximized bitumen production rates. It was concluded that the technique can be used alone or combined with other methods to economically produce bitumens. 2 refs., 7 tabs., 9 figs.

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

    Science.gov (United States)

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

    2018-02-01

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

  9. Diode-laser-based water vapor differential absorption lidar (DIAL) profiler evaluation

    Science.gov (United States)

    Spuler, S.; Weckwerth, T.; Repasky, K. S.; Nehrir, A. R.; Carbone, R.

    2012-12-01

    We are in the process of evaluating the performance of an eye-safe, low-cost, diode-laser-based, water vapor differential absorption lidar (DIAL) profiler. This class of instrument may be capable of providing continuous water vapor and aerosol backscatter profiles at high vertical resolution in the atmospheric boundary layer (ABL) for periods of months to years. The technology potentially fills a national long term observing facility gap and could greatly benefit micro- and meso-meteorology, water cycle, carbon cycle and, more generally, biosphere-hydrosphere-atmosphere interaction research at both weather and climate variability time scales. For the evaluation, the Montana State University 3rd generation water vapor DIAL was modified to enable unattended operation for a period of several weeks. The performance of this V3.5 version DIAL was tested at MSU and NCAR in June and July of 2012. Further tests are currently in progress with Howard University at Beltsville, Maryland; and with the National Weather Service and Oklahoma University at Dallas/Fort Worth, Texas. The presentation will include a comparison of DIAL profiles against meteorological "truth" at the aforementioned locations including: radiosondes, Raman lidars, microwave and IR radiometers, AERONET and SUOMINET systems. Instrument reliability, uncertainty, systematic biases, detection height statistics, and environmental complications will be evaluated. Performance will be judged in the context of diverse scientific applications that range from operational weather prediction and seasonal climate variability, to more demanding climate system process studies at the land-canopy-ABL interface. Estimating the extent to which such research and operational applications can be satisfied with a low cost autonomous network of similar instruments is our principal objective.

  10. Validation of GPS atmospheric water vapor with WVR data in satellite tracking mode

    Science.gov (United States)

    Shangguan, M.; Heise, S.; Bender, M.; Dick, G.; Ramatschi, M.; Wickert, J.

    2015-01-01

    Slant-integrated water vapor (SIWV) data derived from GPS STDs (slant total delays), which provide the spatial information on tropospheric water vapor, have a high potential for assimilation to weather models or for nowcasting or reconstruction of the 3-D humidity field with tomographic techniques. Therefore, the accuracy of GPS STD is important, and independent observations are needed to estimate the quality of GPS STD. In 2012 the GFZ (German Research Centre for Geosciences) started to operate a microwave radiometer in the vicinity of the Potsdam GPS station. The water vapor content along the line of sight between a ground station and a GPS satellite can be derived from GPS data and directly measured by a water vapor radiometer (WVR) at the same time. In this study we present the validation results of SIWV observed by a ground-based GPS receiver and a WVR. The validation covers 184 days of data with dry and wet humidity conditions. SIWV data from GPS and WVR generally show good agreement with a mean bias of -0.4 kg m-2 and an rms (root mean square) of 3.15 kg m-2. The differences in SIWV show an elevation dependent on an rms of 7.13 kg m-2 below 15° but of 1.76 kg m-2 above 15°. Nevertheless, this elevation dependence is not observed regarding relative deviations. The relation between the differences and possible influencing factors (elevation angles, pressure, temperature and relative humidity) are analyzed in this study. Besides the elevation, dependencies between the atmospheric humidity conditions, temperature and the differences in SIWV are found.

  11. The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer

    Science.gov (United States)

    Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

  12. Carbothermic Reduction Kinetics of Phosphorous Vaporization from Tri-calcium Phosphate (TCP) Under Microwave Rapid Heating With/Without the Presence of Fe3O4

    Science.gov (United States)

    Yoshikawa, Noboru; Sunako, Manami; Kawahira, Keita; Suzuki, Koki; Miyamoto, Kazunori; Taniguchi, Shoji

    2018-06-01

    The kinetics of vapor phase dephosphorization from tri-calcium phosphate (TCP) by carbothermic reduction was studied with and without the presence of Fe3O4. Microwave heating was utilized to obtain large variations in the heating rate (HR). In the reduction of TCP alone, the phosphorous removal fraction (RF; equal to ΔP2O5/P2O 5 0 , where ΔP2O5 is the weight change and P2O 5 0 is the P2O5 weight before heating) decreased as the HR increased. In other words, a shorter residence time at a high temperature resulted in a smaller reduction fraction of TCP. An apparently third-order reaction was postulated to account for the kinetics using a fitting simulation based on the additive law of the reaction progress. On the other hand, the phosphorous removal (dephosphorization) rate (RR; equal to ΔP2O3/ t MW, where tMW is the microwave heating time period) increased as the HR increased above 1200 °C. The reduction ratio of Fe3O4 above 1100 °C is higher than 97 pct regardless of the heating rate. The reduction of TCP in the presence of Fe3O4 showed that RF increased slightly with increasing HR despite a shorter residence time at a high temperature. The RR also increased with the HR even though RF decreased to half of the values observed in the cases without Fe3O4 for temperatures above 1200 °C. The practicality and optimal operation conditions of phosphorus vapor removal were discussed.

  13. Carbothermic Reduction Kinetics of Phosphorous Vaporization from Tri-calcium Phosphate (TCP) Under Microwave Rapid Heating With/Without the Presence of Fe3O4

    Science.gov (United States)

    Yoshikawa, Noboru; Sunako, Manami; Kawahira, Keita; Suzuki, Koki; Miyamoto, Kazunori; Taniguchi, Shoji

    2018-03-01

    The kinetics of vapor phase dephosphorization from tri-calcium phosphate (TCP) by carbothermic reduction was studied with and without the presence of Fe3O4. Microwave heating was utilized to obtain large variations in the heating rate (HR). In the reduction of TCP alone, the phosphorous removal fraction (RF; equal to ΔP2O5/P2O5 0 , where ΔP2O5 is the weight change and P2O5 0is the P2O5 weight before heating) decreased as the HR increased. In other words, a shorter residence time at a high temperature resulted in a smaller reduction fraction of TCP. An apparently third-order reaction was postulated to account for the kinetics using a fitting simulation based on the additive law of the reaction progress. On the other hand, the phosphorous removal (dephosphorization) rate (RR; equal to ΔP2O3/t MW, where tMW is the microwave heating time period) increased as the HR increased above 1200 °C. The reduction ratio of Fe3O4 above 1100 °C is higher than 97 pct regardless of the heating rate. The reduction of TCP in the presence of Fe3O4 showed that RF increased slightly with increasing HR despite a shorter residence time at a high temperature. The RR also increased with the HR even though RF decreased to half of the values observed in the cases without Fe3O4 for temperatures above 1200 °C. The practicality and optimal operation conditions of phosphorus vapor removal were discussed.

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

    Science.gov (United States)

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

    2018-05-01

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

  15. Advancements in oxygen generation and humidity control by water vapor electrolysis

    Science.gov (United States)

    Heppner, D. B.; Sudar, M.; Lee, M. C.

    1988-01-01

    Regenerative processes for the revitalization of manned spacecraft atmospheres or other manned habitats are essential for realization of long-term space missions. These processes include oxygen generation through water electrolysis. One promising technique of water electrolysis is the direct conversion of the water vapor contained in the cabin air to oxygen. This technique is the subject of the present program on water vapor electrolysis development. The objectives were to incorporate technology improvements developed under other similar electrochemical programs and add new ones; design and fabricate a mutli-cell electrochemical module and a testing facility; and demonstrate through testing the improvements. Each aspect of the water vapor electrolysis cell was reviewed. The materials of construction and sizing of each element were investigated analytically and sometime experimentally. In addition, operational considerations such as temperature control in response to inlet conditions were investigated. Three specific quantitative goals were established.

  16. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line and...

  17. Water-containing derivative phases of the Srn+1FenO3n+1 series

    International Nuclear Information System (INIS)

    Lehtimaeki, M.; Hirasa, A.; Matvejeff, M.; Yamauchi, H.; Karppinen, M.

    2007-01-01

    The n=1, 2, 3 and ∞ members of the homologous series Sr n+1 Fe n O 3n+1 of layered iron oxides are investigated for their tendency to accept additional layers of water in their crystals. The phases possess a Ruddlesden-Popper-type SrO-(SrO-FeO 2 ) n crystal structure, where the n=∞ limit is nothing but the perovskite structure. It is revealed that the n=1, 2 and 3 phases readily accommodate one or two layers of water between adjacent SrO layers, whereas the n=∞ member which lacks the SrO-SrO double-layer unit remains intact in the presence of water. The speed of the water intercalation process is found to decrease with increasing n. Among the layered water derivatives, the n=2 phase with two water molecules per formula unit, i.e. Sr 3 Fe 2 O 7 .2H 2 O, was found to be most stable. - Graphical abstract: Water-containing derivative phases obtained from the homologous series of Sr n+1 Fe n O 3n+1 Ruddlesden-Popper phases through topotactic water intercalation

  18. Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach

    Science.gov (United States)

    Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

    2013-01-01

    Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

  19. Sorption and desorption of tritiated water vapor on piping materials of nuclear fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Satoru; Ohmori, Rumi [Tokyo Univ. (Japan). Faculty of Engineering

    1996-10-01

    Sorption and desorption of D{sub 2}O on Cr{sub 2}O{sub 3}, NiO, SS316 powders were studied at ambient temperature. When D{sub 2}O were contacted with samples after drying at 303K, broad peak was observed at 2100-2700cm{sup -1} on Cr{sub 2}O{sub 3} and NiO. Sorption and desorption rate depended on wave numbers. Isotope exchange rate with H{sub 2}O vapor was faster than dry desorption rate. By heating pretreatment, sorption amount and desorption rate for Cr{sub 2}O{sub 3} and NiO decreased. For SS316, broad peak was observed only after heating pretreatment at 673K. (author)

  20. Characterization of a Compact Water Vapor Radiometer

    Science.gov (United States)

    Gill, Ajay; Selina, Rob

    2018-01-01

    We report on laboratory test results of the Compact Water Vapor Radiometer (CWVR) prototype for the Karl G. Jansky Very Large Array (VLA), a five-channel design centered around the 22 GHz water vapor line. Fluctuations in perceptible water vapor cause fluctuations in atmospheric brightness emission, which are assumed to be proportional to phase fluctuations of the astronomical signal seen by an antenna. The design is intended to support empirical radiometric phase corrections for each baseline in the array.The dynamic range, channel isolation, and gain stability of the device were characterized. The device has a useful dynamic range of order 18 dB after calibration, and the CWVR channel isolation requirement of test, the diode detectors were operated in the square-law region, and a K-band noise diode was used as the broadband input power source to the CWVR over a period of 64 hours. Results indicate that the fluctuations in output counts are negatively correlated to the CWVR enclosure ambient temperature, with a change of ~ 405 counts per 1° C change in temperature.A correction for the CWVR ambient temperature makes a considerable improvement in stability for τ > 102.6 sec. With temperature corrections, the single channel and channel difference gain stability per channel is test results indicate that the CWVR meets required specifications for dynamic range, channel isolation, and gain stability in order to proceed with testing on a pair of VLA antennas.

  1. Macroscopic modeling for heat and water vapor transfer in dry snow by homogenization.

    Science.gov (United States)

    Calonne, Neige; Geindreau, Christian; Flin, Frédéric

    2014-11-26

    Dry snow metamorphism, involved in several topics related to cryospheric sciences, is mainly linked to heat and water vapor transfers through snow including sublimation and deposition at the ice-pore interface. In this paper, the macroscopic equivalent modeling of heat and water vapor transfers through a snow layer was derived from the physics at the pore scale using the homogenization of multiple scale expansions. The microscopic phenomena under consideration are heat conduction, vapor diffusion, sublimation, and deposition. The obtained macroscopic equivalent model is described by two coupled transient diffusion equations including a source term arising from phase change at the pore scale. By dimensional analysis, it was shown that the influence of such source terms on the overall transfers can generally not be neglected, except typically under small temperature gradients. The precision and the robustness of the proposed macroscopic modeling were illustrated through 2D numerical simulations. Finally, the effective vapor diffusion tensor arising in the macroscopic modeling was computed on 3D images of snow. The self-consistent formula offers a good estimate of the effective diffusion coefficient with respect to the snow density, within an average relative error of 10%. Our results confirm recent work that the effective vapor diffusion is not enhanced in snow.

  2. Field campaign LINEX 96/1 - possibilities of water vapor observation in the free atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Steinhagen, H.; Dier, H.; Engelbart, D.; Goersdorf, U.; Lehmann, V.; Leiterer, U.; Neisser, J. [Deutscher Wetterdienst, Lindenberg (Germany). Meteorologisches Observatorium; Bakan, S. [Hamburg Univ. (Germany). Meteorologisches Inst.; Boesenberg, J.; Jansen, F.; Wulfmeyer, V. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Fischer, J. [Freie Univ. Berlin (Germany). Inst. fuer Weltraumwissenschaften; Gendt, G. [GeoForschungsZentrum Potsdam (Germany); Gueldner, J. [Deutscher Wetterdienst, Potsdam (Germany). Meteorologisches Observatorium

    1998-12-01

    LINEX 96/1 was a field experiment to assess information content, accuracy, and availability for different remote sensing techniques measuring water vapor. An important goal of LINEX 96/1 was the test of a new differential absorption lidar (DIAL) developed by the MPI fuer meteorologie Hamburg. Comparisons of DIAL with rawinsonde and tethersonde measurements showed an excellent accuracy of the DIAL method in the determination of water vapor with high vertical and temporal resolution. The operation of the microwave radiometer WVR-1100 showed a high availability of water vapor and liquid water column content measurements except during rain. Microwave radiometers are reliable systems to measure the precipitable water vapor and liquid water content under unattended operational conditions with high accuracy and temporal resolution. Measurements of the water vapor column content by ground-based GPS receivers proved highly reliable. Comparisons with corresponding values of the microwave radiometer showed a bias less than 0.6 mm and a standard deviation less than 0.9 mm. The main problem of an operational use of this new information is that the evaluated data are not available in real-time because, at present, the data have to be postprocessed in a ground control center. During LINEX 96/1, possibilities for estimation of water vapor column content from sun and star photometer measurements were also demonstrated. The comparison of the precipitable water vapor content measurements of sun and star photometers, microwave radiometer, and rawinsondes RS 80 showed a good agreement. Unfortunately, the use of optical methods like sun and star photometers is restricted by cloudy conditions. 28 refs.

  3. Heavy-water (D2O) take-up-induced lattice expansion in the high-temperature proton conductor Ba3Ca1.18Nb1.82O9-δ

    International Nuclear Information System (INIS)

    Papathanassopoulos, K.; Wenzl, H.; Schober, T.

    1997-01-01

    Dimensional changes of the high-temperature proton conductor Ba 3 Ca 1.18 Nb 1.82 O 9-δ , when exposed to D 2 O vapor, were investigated using length-change and precision density measurements. Such information is essential for possible applications of proton conductors in solid oxide fuel cells and humidity and hydrogen sensors. A linear increase of the sample lengths with increases in the deuterium content was observed. Comparison of the present D 2 O data with those that were previously obtained for H 2 O showed that there was a small isotope effect in the lattice expansion. The fact that the length-change-versus-hydrogen-isotope-concentration curves were almost isotope independent supported the validity of the take-up reaction H 2 O(g) + V sm-bulletsm-bullet O + O x O right-reversible 2OH sm-bullet O , where V O is the vacancies in the oxygen sublattice and OH sm-bullet O is the proton that are embedded in the electron cloud of an oxygen atom. In regard to the latter equation, it was found that small islands of silver, palladium, nickel, and platinum act as catalytic promoters of the reaction and lead, for given heavy-water-steam exposure conditions, to an increase of water absorption of up to 100%, when compared with samples without the catalytic surface layers

  4. Improved waste water vapor compression distillation technology. [for Spacelab

    Science.gov (United States)

    Johnson, K. L.; Nuccio, P. P.; Reveley, W. F.

    1977-01-01

    The vapor compression distillation process is a method of recovering potable water from crewman urine in a manned spacecraft or space station. A description is presented of the research and development approach to the solution of the various problems encountered with previous vapor compression distillation units. The design solutions considered are incorporated in the preliminary design of a vapor compression distillation subsystem. The new design concepts are available for integration in the next generation of support systems and, particularly, the regenerative life support evaluation intended for project Spacelab.

  5. Development and Validation of Water Vapor Tracers as Diagnostics for the Atmospheric Hydrologic Cycle

    Science.gov (United States)

    Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding of the local and remote sources of water vapor can be a valuable diagnostic in understanding the regional atmospheric hydrologic cycle. In the present study, we have implemented passive tracers as prognostic variables to follow water vapor evaporated in predetermined regions until the water tracer precipitates. The formulation of the sources and sinks of tracer water is generally proportional to the prognostic water vapor variable. Because all water has been accounted for in tracers, the water vapor variable provides the validation of the tracer water and the formulation of the sources and sinks. The tracers have been implemented in a GEOS General Circulation Model (GCM) simulation consisting of several summer periods to determine the source regions of precipitation for the United States and India. The recycling of water and interannual variability of the sources of water will be examined. Potential uses in GCM sensitivity studies, predictability studies and data assimilation will be discussed.

  6. Water Vapor Tacers as Diagnostics of the Regional Atmospheric Hydrologic Cycle

    Science.gov (United States)

    Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Understanding of the local and remote sources of water vapor can be a valuable diagnostic in understanding the regional atmospheric hydrologic cycle, especially in North America where moisture transport and local evaporation are important sources of water for precipitation. In the present study, we have implemented passive tracers as prognostic variables to follow water vapor evaporated in predetermined regions until the water tracer precipitates. All evaporative sources of water are accounted for by tracers, and the water vapor variable provides the validation of the tracer water and the formulation of the sources and sinks. The Geostationary Operational Environmental Satellites General Circulation Model (GEOS GCM) is used to simulate several summer periods to determine the source regions of precipitation for the United States and India. Using this methodology, a detailed analysis of the recycling of water, interannual variability of the sources of water and links to the Great Plains low-level jet and North American monsoon will be presented. Potential uses in GCM sensitivity studies, predictability studies and data assimilation especially regarding the North American monsoon and GEWEX America Prediction Project (GAPP) will be discussed.

  7. Site of water vapor absorption in the desert cockroach, Arenivaga investigata.

    Science.gov (United States)

    O'Donnell, M J

    1977-01-01

    The desert cockroach, Arenivaga investigata, can gain weight by absorption of water-vapor from unsaturated atmospheres above 82.5% relative humidity. Blocking the anus or the dorsal surface with wax does not prevent water vapor uptake, but interference with movements of the mouthparts or blocking the mouth with wax-prevents such uptake. Weight gains are associated with the protrusion from the mouth of two bladder-like extensions of the hypopharynx. During absorption these structures are warmer than the surrounding mouthparts, their surface temperature increasing with relative humidity. This suggests that the surfaces of the bladder-like structures function at least as sites for condensation of water vapor, but the precise location of its transfer into the hemolymph has not yet been identified. Images PMID:266217

  8. Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

    Science.gov (United States)

    Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Padolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Mahoney, Michael J.; Richard, Erik

    2002-01-01

    This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE III-Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999/2000 winter season. Aircraft-based water vapor, carbon monoxide, and ozone measurements were analyzed so as to establish how deeply tropospheric air mixes into the Arctic lowermost stratosphere and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to-stratosphere exchange extends into the Arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases with altitude most rapidly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of above 5ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20% of the parcels which have ozone values of 300-350 ppbv experiencing ice saturation in a given 10 day period. Third, during early spring, temperatures at the troposphere are cold enough so that 5-10% of parcels experience relative humidities above 100%, even if the water content is as low as 5 ppmv. The implication is that during this period, dynamical processes near the Arctic tropopause can dehydrate air and keep the Arctic tropopause region very dry during early spring.

  9. Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone

    Science.gov (United States)

    Milly, Paul C.D.

    1996-01-01

    The response of water in the unsaturated zone to seasonal changes of temperature (T) is determined analytically using the theory of nonisothermal water transport in porous media, and the solutions are tested against field observations of moisture potential and bomb fallout isotopic (36Cl and 3H) concentrations. Seasonally varying land surface temperatures and the resulting subsurface temperature gradients induce thermal vapor diffusion. The annual mean vertical temperature gradient is close to zero; however, the annual mean thermal vapor flux is downward, because the temperature‐dependent vapor diffusion coefficient is larger, on average, during downward diffusion (occurring at high T) than during upward diffusion (low T). The annual mean thermal vapor flux is shown to decay exponentially with depth; the depth (about 1 m) at which it decays to e−1of its surface value is one half of the corresponding decay depth for the amplitude of seasonal temperature changes. This depth‐dependent annual mean flux is effectively a source of water, which must be balanced by a flux divergence associated with other transport processes. In a relatively humid environment the liquid fluxes greatly exceed the thermal vapor fluxes, so such a balance is readily achieved without measurable effect on the dynamics of water in the unsaturated zone. However, if the mean vertical water flux through the unsaturated zone is very small (theoretical prediction is supported by long‐term field measurements in the Chihuahuan Desert. The analysis also makes predictions, confirmed by the field observations, regarding the seasonal variations of matric potential at a given depth. The conceptual model of unsaturated zone water transport developed here implies the possibility of near‐surface trapping of any aqueous constituent introduced at the surface.

  10. Microwave measurements of water vapor partial pressure at high temperatures

    International Nuclear Information System (INIS)

    Latorre, V.R.

    1991-01-01

    One of the desired parameters in the Yucca Mountain Project is the capillary pressure of the rock comprising the repository. This parameter is related to the partial pressure of water vapor in the air when in equilibrium with the rock mass. Although there are a number of devices that will measure the relative humidity (directly related to the water vapor partial pressure), they generally will fail at temperatures on the order of 150C. Since thee author has observed borehole temperatures considerably in excess of this value in G-Tunnel at the Nevada Test Site (NTS), a different scheme is required to obtain the desired partial pressure data at higher temperatures. This chapter presents a microwave technique that has been developed to measure water vapor partial pressure in boreholes at temperatures up to 250C. The heart of the system is a microwave coaxial resonator whose resonant frequency is inversely proportional to the square root of the real part of the complex dielectric constant of the medium (air) filling the resonator. The real part of the dielectric constant of air is approximately equal to the square of the refractive index which, in turn, is proportional to the partial pressure of the water vapor in the air. Thus, a microwave resonant cavity can be used to measure changes in the relative humidity or partial pressure of water vapor in the air. Since this type of device is constructed of metal, it is able to withstand very high temperatures. The actual limitation is the temperature limit of the dielectric material in the cable connecting the resonator to its driving and monitoring equipment-an automatic network analyzer in our case. In the following sections, the theory of operation, design, construction, calibration and installation of the microwave diagnostics system is presented. The results and conclusions are also presented, along with suggestions for future work

  11. Atmospheric Pre-Corrected Differential Absorption Techniques to Retrieve Columnar Water Vapor: Application to AVIRIS 91/95 Data

    Science.gov (United States)

    Schlaepfer, Daniel; Borel, Christoph C.; Keller, Johannes; Itten, Klaus I.

    1996-01-01

    Water vapor is one of the main forces for weather development as well as for mesoscale air transport processes. The monitoring of water vapor is therefore an important aim in remote sensing of the atmosphere. Current operational systems for water vapor detection use primarily the emission in the thermal infrared (AVHRR, GOES, ATSR, Meteosat) or in the microwave radiation bands (DMSP). The disadvantage of current satellite systems is either a coarse spatial (horizontal) resolution ranging from one to tens of kilometers or a limited insight into the lower atmosphere. Imaging spectrometry on the other hand measures total column water vapor contents at a high spatial horizontal resolution and has therefore the potential of filling these gaps. The sensors of the AVIRIS instrument are capable of acquiring hyperspectral data in 224 bands located in the visible and near infrared at 10 nm resolution. This data includes the information on constituents of the earth's surface as well as of the atmosphere. The optical measurement of water vapor can be performed using sensor channels located in bands or lines of the absorption spectrum. The AVIRIS sensor has been used to retrieve water vapor and with less accuracy carbon dioxide, oxygen and ozone. To retrieve the water vapor amount, the so called differential absorption technique has been applied. The goal of this technique is to eliminate background factors by taking a ratio between channels within the absorption band and others besides the band. Various ratioing methods on the basis of different channels and calculation techniques were developed. The influence of a trace gas of interest on the radiance at the sensor level is usually simulated by using radiative transfer codes. In this study, the spectral transmittance and radiance are calculated by MODTRAN3 simulations with the new DISORT option. The objective of this work is to test the best performing differential absorption techniques for imaging spectrometry of

  12. Water adsorption induced in-plane domain switching on BaTiO{sub 3} surface

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Bai, Y.; Su, Y. J., E-mail: yjsu@ustb.edu.cn [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Wang, B. C. [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Multiscale Materials Modelling group, Department of Materials and Engineering, Royal Institute of Technology, SE-10044 Stockholm (Sweden)

    2015-09-07

    In this study, the influences of the adsorption of water molecules on the changes in the atomic and electric structures of BaTiO{sub 3} surface were investigated using ab initio calculation. Water molecules are molecularly and dissociatively adsorbed on the BaTiO{sub 3} surface, which makes electrons transfer from water molecules to the BaTiO{sub 3} surface. The redistribution of electrons in the BaTiO{sub 3} surface layers weakens the Ba-O interactions and strengthens the Ti-O interactions, so that the Ti atom shifts in TiO{sub 2} plane, i.e., an in-plane domain switching. The adsorption of water molecules on BaTiO{sub 3} surfaces also results in a reduction in the surface rumpling.

  13. GROUND WATER SAMPLING OF VOCS IN THE WATER/CAPILLARY FRINGE AREA FOR VAPOR INTRUSION ASSESSMENT

    Science.gov (United States)

    Vapor intrusion has recently been considered a major pathway for increased indoor air contamination from certain volatile organic contaminants (VOCs). The recent Draft EPA Subsurface Vapor Intrusion Guidance Document states that ground water samples should be obtained from the u...

  14. Laser absorption spectroscopy of water vapor confined in nanoporous alumina: wall collision line broadening and gas diffusion dynamics.

    Science.gov (United States)

    Svensson, Tomas; Lewander, Märta; Svanberg, Sune

    2010-08-02

    We demonstrate high-resolution tunable diode laser absorption spectroscopy (TDLAS) of water vapor confined in nanoporous alumina. Strong multiple light scattering results in long photon pathlengths (1 m through a 6 mm sample). We report on strong line broadening due to frequent wall collisions (gas-surface interactions). For the water vapor line at 935.685 nm, the HWHM of confined molecules are about 4.3 GHz as compared to 2.9 GHz for free molecules (atmospheric pressure). Gas diffusion is also investigated, and in contrast to molecular oxygen (that moves rapidly in and out of the alumina), the exchange of water vapor is found very slow.

  15. Investigation of OH dynamics in the argon sensitized pulse radiolysis of water vapor

    International Nuclear Information System (INIS)

    Bera, R.K.; Hanrahan, R.J.

    1986-01-01

    Reactions of OH radical were studied in systems containing 650 torr Ar and from 0.5 to 9 torr H 2 O using the method of pulse radiolysis-absorption spectroscopy. It was found that initial concentrations of OH radical increased as a function of water vapor pressure. Although loss of OH with time followed approximate second order kinetics, the raw data were fitted arbitrarily to a first order rate expression, because a second order fit requires knowledge of absolute initial OH concentrations. These can be computed from measured initial OH absorption if the extinction coefficient is known, but an accurate value was not available initially. The half-life for OH loss decreased at higher water pressures. Dependence of OH half-life on OH concentration occurs because homogeneous OH loss processes are second order in reaction intermediates, whose concentration increases with added H 2 O. A contribution by water in chaperoning OH/OH and OH/H combination is also important

  16. Beeswax–chitosan emulsion coated paper with enhanced water vapor barrier efficiency

    International Nuclear Information System (INIS)

    Zhang, Weiwei; Xiao, Huining; Qian, Liying

    2014-01-01

    Graphical abstract: - Highlights: • The water vapor barrier efficiency of paper was enhanced via green-based emulsion coating. • Extremely high lipid content in the emulsion coating layer was firstly utilized to reduce WVTR in emulsion-based film. • A controlled WVTR of beeswax–chitosan emulsion coating could be obtained by dying at specific temperature. - Abstract: For lipid–hydrocolloid emulsion based film, the increase of lipid amount would improve its water vapor barrier property, but also reduce the mechanical strength of the film in the meantime thus leading to a compromised lipid content in the film. However, when the emulsion is coated on paper surface, more lipid could be used for emulsion preparation to enhance the moisture resistance without considering the weakened strength of the film induced by lipid, because the mechanical properties of emulsion coated paper is mainly governed by the strength of base paper instead of the coating layer. In this study, beeswax–chitosan emulsion was first prepared and then coated on paper surface to improve paper's water vapor barrier and water resistance properties. The range and variance analysis of orthogonal test design showed that the order of priorities of the factors accordingly was beeswax solid content, drying temperature and chitosan concentration. The effect of drying temperature on water vapor transmission rate (WVTR) and water contact angle of coated paper was further investigated using 1.2 wt% chitosan and 96% beeswax solid content in the coating layer. The results indicated that water vapor barrier property was in accordance with the density of the coating layer. Atomic force microscope (AFM) was also used to characterize the surface morphology and explain the hydrophobicity of beeswax–chitosan coated paper. It was found that surface beeswax particles melted to wrinkle at high drying temperatures, while roughness values maintained at micro-scale over the temperature range investigated

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

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  18. Impact of groundwater levels on evaporation and water-vapor fluxes in highly saline soils

    Science.gov (United States)

    Munoz, J. F.; Hernández, M. F.; Braud, I.; Gironas, J. A.; Suarez, F. I.

    2012-12-01

    In aquifers of arid and hyper-arid zones, such as those occurring in the Chilean Andes high plateau, it is important to determine both the quantity and location of water discharges at the temporal scales of interest to close the basin's water budget and thus, to manage the water resource properly. In zones where shallow aquifers are the main source of water, overexploitation of the water resource changes the dynamics of water, heat and solute transport in the vadose zone. As aquifers are exploited, fluctuations in depth to groundwater are exacerbated. These fluctuations modify both soil structure and evaporation from the ground, which is typically the most important discharge from the water budget and is very difficult to estimate. Therefore, a correct quantification of evaporation from these soils is essential to improve the accuracy of the water balance estimation. The objective of this study was to investigate the evaporation processes and water-vapor fluxes in a soil column filled with a saline soil from the Salar del Huasco basin, Chile. Water content, electrical conductivity and temperature at different depths in the soil profile were monitored to determine the liquid and vapor fluxes within the soil column. The results showed that evaporation is negligible when the groundwater table is deeper than 1 m. For shallower groundwater levels, evaporation increases in an exponential fashion reaching a value of 3 mm/day when the groundwater table is near the surface of the ground. These evaporation rates are on the same order of magnitude than the field measurements, but slightly lower due to the controlled conditions maintained in the laboratory. Isothermal fluid fluxes were predominant over the non-isothermal fluid and water vapor fluxes. The net flux for all the phreatic levels tested in the laboratory showed different behaviors, with ascending or descending flows as a consequence of changes in water content and temperature distribution within the soil. It was

  19. An interim reference model for the variability of the middle atmosphere water vapor distribution

    Science.gov (United States)

    Remsberg, E. E.; Russell, J. M., III; Wu, C.-Y.

    1990-01-01

    A reference model for the middle atmosphere water vapor distribution for some latitudes and seasons was developed using two data sets. One is the seven months of Nimbus LIMS data obtained during November 1978 to May 1979 over the range 64 deg S - 84 deg N latitude and from about 100-mb to 1-mb altitude, and the other is represented by water vapor profiles from 0.2 mb to 0.01 mb in the mid-mesosphere, measured on ground at several fixed mid-latitude sites in the Northern Hemisphere, using microwave-emission techniques. This model provides an interim water vapor profile for the entire vertical range of the middle atmosphere, with accuracies of better than 25 percent. The daily variability of stratospheric water vapor profiles about the monthly mean is demonstrated, and information is provided on the longitudinal variability of LIMS water vapor profiles about the daily, weekly, and monthly zonal means.

  20. CFD modeling of condensation process of water vapor in supersonic flows

    DEFF Research Database (Denmark)

    Yang, Yan; Walther, Jens Honore; Yan, Yuying

    2017-01-01

    The condensation phenomenon of vapor plays an important role in various industries, such as the steam flow in turbines and refrigeration system. A mathematical model is developed to predict the spontaneous condensing phenomenon in the supersonic flows using the nucleation and droplet growth...... theories. The numerical approach is validated with the experimental data, which shows a good agreement between them. The condensation characteristics of water vapor in the Laval nozzle are described in detail. The results show that the condensation process is a rapid variation of the vapor-liquid phase...... change both in the space and in time. The spontaneous condensation of water vapor will not appear immediately when the steam reaches the saturation state. Instead, it occurs further downstream the nozzle throat, where the steam is in the state of supersaturation....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-09

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  3. Study of the effect of water vapor on a resistive plate chamber with glass electrodes

    CERN Document Server

    Sakai, H H; Teramoto, Y; Nakano, E E; Takahashi, T T

    2002-01-01

    We studied the effects of water vapor on the efficiencies of resistive plate chambers with glass electrodes, operated in the streamer mode. With moisture in the chamber gas that has freon as a component (water vapor approx 1000 ppm), a decrease in the efficiency (approx 20%) has been observed after operating for a period of several weeks to a few months. From our study, the cause of the efficiency decrease was identified as a change on the cathode surface. In addition, a recovery method was found: flushing for 1 day with argon bubbled through water containing >=3% ammonia, followed by a few weeks of training with dry gas.

  4. Relative spectral absorption of solar radiation by water vapor and cloud droplets

    Science.gov (United States)

    Davies, R.; Ridgway, W. L.

    1983-01-01

    A moderate (20/cm) spectral resolution model which accounts for both the highly variable spectral transmission of solar radiation through water vapor within and above cloud, as well as the more slowly varying features of absorption and anisotropic multiple scattering by the cloud droplets, is presented. Results from this model as applied to the case of a typical 1 km thick stratus cloud in a standard atmosphere, with cloud top altitude of 2 km and overhead sun, are discussed, showing the relative importance of water vapor above the cloud, water vapor within the cloud, and cloud droplets on the spectral absorption of solar radiation.

  5. Photo-induced current and its degradation in Al{sub 4}C{sub 3}/Al{sub 2}O{sub 3} (0001) grown by metalorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dohyung, E-mail: kim@ee.tokushima-u.ac.jp [Graduate School of Advanced Technology and Science, The University of Tokushima, 2-1 Minami-josanjima, Tokushima 770-8506 (Japan); Onishi, Yuya; Oki, Ryuji [Graduate School of Advanced Technology and Science, The University of Tokushima, 2-1 Minami-josanjima, Tokushima 770-8506 (Japan); Sakai, Shiro [Institute of Technology Science, The University of Tokushima, 2-1 Minami-josanjima, Tokushima 770-8506 (Japan)

    2014-04-30

    Al{sub 4}C{sub 3} layers have been grown on Al{sub 2}O{sub 3} (0001) by metalorganic chemical vapor deposition. Trimethylaluminum and methane were used as source materials for aluminum and carbon, respectively. Depending on the growth conditions, the growth rate was significantly changed. The most suitable growth temperature was 1150 °C. Fresh samples had a yellowish color. Peaks at 32 and 35° observed by 2θ–ω mode X-ray diffraction scans confirmed the presence of hexagonal Al{sub 4}C{sub 3}. Experiments detected photo-induced current (PIC). PIC measured at 30 V dc was observed at Al{sub 4}C{sub 3}/Al{sub 2}O{sub 3} (0001) at the 10 nA scale. PIC in Al{sub 4}C{sub 3} increased with a decrease in the irradiated wavelength. This phenomenon was also observed in absorption coefficient experiments. It was also verified that the electrical conductivity of Al{sub 4}C{sub 3} significantly deteriorated due to oxidation. PIC was also continuously reduced during Al{sub 4}C{sub 3} oxidation. After a certain period of time, it was observed that the Al{sub 4}C{sub 3} layer separated from the Al{sub 2}O{sub 3} (0001) substrate. These results suggest that PIC can be useful in photodetectors that can be used in vacuum or in other gases that do not contain oxygen. - Highlights: • Al{sub 4}C{sub 3} layers had been grown on Al{sub 2}O{sub 3} (0001) by metalorganic chemical vapor deposition. • The growth rate abruptly increased above the temperature of 1100 °C. • Photo-induced current (PIC) was observed when the light was incident of the devices. • PIC was unrelated to the presence of a metal–semiconductor junction. • PIC was decreased during Al{sub 4}C{sub 3} oxidation process.

  6. Tritium inventory in Li2ZrO3 blanket

    International Nuclear Information System (INIS)

    Nishikawa, M.; Baba, A.

    1998-01-01

    Recently, we have presented the way to estimate the tritium inventory in a solid breeder blanket considering effects of diffusion of tritium in the grain, absorption of water in the bulk of grain, and adsorption of water on the surface of grain, together with two types of isotope exchange reactions. It is reported in our previous paper that the estimated tritium inventory for a LiAlO 2 blanket agrees well with data observed in various in situ experiments when the effective diffusivity of tritium from the EXOTIC-6 experiment is used and that the better agreement is obtained when existence of some water vapor is assumed in the purge gas. The same way as used for a LiAlO 2 blanket is applied to a Li 2 ZrO 3 blanket in this study and the estimated tritium inventory shows a good agreement with data obtained in such in situ experiments as MOZART, EXOTIC-6 and TRINE experiments. (orig.)

  7. An efficient method for computing the absorption of solar radiation by water vapor

    Science.gov (United States)

    Chou, M.-D.; Arking, A.

    1981-01-01

    Chou and Arking (1980) have developed a fast but accurate method for computing the IR cooling rate due to water vapor. Using a similar approach, the considered investigation develops a method for computing the heating rates due to the absorption of solar radiation by water vapor in the wavelength range from 4 to 8.3 micrometers. The validity of the method is verified by comparison with line-by-line calculations. An outline is provided of an efficient method for transmittance and flux computations based upon actual line parameters. High speed is achieved by employing a one-parameter scaling approximation to convert an inhomogeneous path into an equivalent homogeneous path at suitably chosen reference conditions.

  8. Water Vapor Tracers as Diagnostics of the Regional Hydrologic Cycle

    Science.gov (United States)

    Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Numerous studies suggest that local feedback of surface evaporation on precipitation, or recycling, is a significant source of water for precipitation. Quantitative results on the exact amount of recycling have been difficult to obtain in view of the inherent limitations of diagnostic recycling calculations. The current study describes a calculation of the amount of local and remote geographic sources of surface evaporation for precipitation, based on the implementation of three-dimensional constituent tracers of regional water vapor sources (termed water vapor tracers, WVT) in a general circulation model. The major limitation on the accuracy of the recycling estimates is the veracity of the numerically simulated hydrological cycle, though we note that this approach can also be implemented within the context of a data assimilation system. In the WVT approach, each tracer is associated with an evaporative source region for a prognostic three-dimensional variable that represents a partial amount of the total atmospheric water vapor. The physical processes that act on a WVT are determined in proportion to those that act on the model's prognostic water vapor. In this way, the local and remote sources of water for precipitation can be predicted within the model simulation, and can be validated against the model's prognostic water vapor. As a demonstration of the method, the regional hydrologic cycles for North America and India are evaluated for six summers (June, July and August) of model simulation. More than 50% of the precipitation in the Midwestern United States came from continental regional sources, and the local source was the largest of the regional tracers (14%). The Gulf of Mexico and Atlantic regions contributed 18% of the water for Midwestern precipitation, but further analysis suggests that the greater region of the Tropical Atlantic Ocean may also contribute significantly. In most North American continental regions, the local source of precipitation is

  9. The Effect of Cirrus Clouds on Water Vapor Transport in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Lei, L.; McCormick, M. P.; Anderson, J.

    2017-12-01

    Water vapor plays an important role in the Earth's radiation budget and stratospheric chemistry. It is widely accepted that a large percentage of water vapor entering the stratosphere travels through the tropical tropopause and is dehydrated by the cold tropopause temperature. The vertical transport of water vapor is also affected by the radiative effects of cirrus clouds in the tropical tropopause layer. This latter effect of cirrus clouds was investigated in this research. The work focuses on the tropical and mid-latitude region (50N-50S). Water vapor data from the Microwave Limb Sounder (MLS) and cirrus cloud data from the Cloud-Aerosol Lidar and Infrared pathfinder Satellite Observation (CALIPSO) instruments were used to investigate the relationship between the water vapor and the occurrence of cirrus cloud. A 10-degree in longitude by 10-degree in latitude resolution was chosen to bin the MLS and CALIPSO data. The result shows that the maximum water vapor in the upper troposphere (below 146 hPa) is matched very well with the highest frequency of cirrus cloud occurrences. Maximum water vapor in the lower stratosphere (100 hPa) is partly matched with the maximum cirrus cloud occurrence in the summer time. The National Oceanic and Atmospheric Administration Interpolated Outgoing Longwave Radiation data and NCEP-DOE Reanalysis 2 wind data were used also to investigate the relationship between the water vapor entering the stratosphere, deep convection, and wind. Results show that maximum water vapor at 100 hPa coincides with the northern hemisphere summer-time anticyclone. The effects from both single-layer cirrus clouds and cirrus clouds above the anvil top on the water vapor entering the stratosphere were also studied and will be presented.

  10. Monitoring middle-atmospheric water vapor over Seoul by using a 22 GHz ground-based radiometer SWARA

    Science.gov (United States)

    Ka, Soohyun; de Wachter, Evelyn; Kaempfer, Niklaus; Oh, Jung Jin

    2010-10-01

    Water vapor is the strongest natural greenhouse gas in the atmosphere. It is most abundant in the troposphere at low altitudes, due to evaporation at the ocean surface, with maximum values of around 6 g/kg. The amount of water vapor reaches a minimum at tropopause level and increases again in the middle atmosphere through oxidation of methane and vertical transport. Water vapor has both positive and negative effects on global warming, and we need to study how it works on climate change by monitoring water vapor concentration in the middle atmosphere. In this paper, we focus on the 22 GHz ground-based radiometer called SWARA (Seoul Water vapor Radiometer) which has been operated at Sookmyung women's university in Seoul, Korea since Oct. 2006. It is a joint project of the University of Bern, Switzerland, and the Sookmyung Women's University of Seoul, South Korea. The SWARA receives 22.235 GHz emitted from water vapor spontaneously and converts down to 1.5 GHz with +/- 0.5 GHz band width in 61 kHz resolution. To represent 22.235 GHz water vapor spectrum precisely, we need some calibration methods because the signal shows very weak intensity in ~0.1 K on the ground. For SWARA, we have used the balancing and the tipping curve methods for a calibration. To retrieve the water vapor profile, we have applied ARTS and Qpack software. In this paper, we will present the calibration methods and water vapor variation over Seoul for the last 4 years.

  11. Removal of diethyl phthalate from water solution by adsorption, photo-oxidation, ozonation and advanced oxidation process (UV/H2O2, O3/H2O2 and O3/activated carbon)

    International Nuclear Information System (INIS)

    Medellin-Castillo, Nahum A.; Ocampo-Pérez, Raúl; Leyva-Ramos, Roberto; Sanchez-Polo, Manuel; Rivera-Utrilla, José; Méndez-Díaz, José D.

    2013-01-01

    The objective of this work was to compare the effectiveness of conventional technologies (adsorption on activated carbon, AC, and ozonation) and technologies based on advanced oxidation processes, AOPs, (UV/H 2 O 2 , O 3 /AC, O 3 /H 2 O 2 ) to remove phthalates from aqueous solution (ultrapure water, surface water and wastewater). Diethyl phthalate (DEP) was chosen as a model pollutant because of its high water solubility (1080 mg/L at 293 K) and toxicity. The activated carbons showed a high adsorption capacity to adsorb DEP in aqueous solution (up to 858 mg/g), besides the adsorption mechanism of DEP on activated carbon is governed by dispersive interactions between π electrons of its aromatic ring with π electrons of the carbon graphene planes. The photodegration process showed that the pH solution does not significantly affect the degradation kinetics of DEP and the first-order kinetic model satisfactorily fitted the experimental data. It was observed that the rate of decomposition of DEP with the O 3 /H 2 O 2 and O 3 /AC systems is faster than that with only O 3 . The technologies based on AOPs (UV/H 2 O 2 , O 3 /H 2 O 2 , O 3 /AC) significantly improve the degradation of DEP compared to conventional technologies (O 3 , UV). AC adsorption, UV/H 2 O 2 , O 3 /H 2 O 2 , and O 3 /AC showed a high yield to remove DEP; however, the disadvantage of AC adsorption is its much longer time to reach maximum removal. The best system to treat water (ultrapure and natural) polluted with DEP is the O 3 /AC one since it achieved the highest DEP degradation and TOC removal, as well as the lower water toxicity. -- Highlights: ► Activated carbons showed a high adsorption capacity (up to 858 mg/g) to remove DEP. ► The pH solution did not significantly affect the photodegradation kinetics of DEP. ► The O 3 /H 2 O 2 and O 3 /AC systems were more efficient than O 3 to degrade DEP. ► The generation of HO • from O 3 was enhanced by ACs, mainly by those of basic nature. ► O

  12. Water vapor stable isotope observations from tropical Australia

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    The response of the tropical hydrological cycle to anthropogenically induced changes in radiative forcing is one of the largest discrepancies between climate models. Paleoclimate archives of the stable isotopic composition of precipitation in the tropics indicate a relationship with precipitation amount that could be exploited to study past hydroclimate and improve our knowledge of how this region responds to changes in climate forcing. Recently modelling studies of convective parameterizations fitted with water isotopes and remote sensing of water vapor isotopes in the tropics have illustrated uncertainty in the assumed relationship with rainfall amount. Therefore there is a need to collect water isotope data in the tropics that can be used to evaluate these models and help identify the relationships between the isotopic composition of meteoric waters and rainfall intensity. However, data in this region is almost non-existent. Here we present in-situ water vapor isotopic measurements and the HDO retrievals from the co-located Total Column Carbon Observing Network (TCCON) site at Darwin in Tropical Australia. The Darwin site is interestingly placed within the tropical western pacific region and is impacted upon by a clear monsoonal climate, and key climate cycles including ENSO and Madden Julian Oscillations. The analysis of the data illustrated relationships between water vapor isotopes and humidity which demonstrated the role of precipitation processes in the wet season and air mass mixing during the dry season. Further the wet season observations show complex relationships between humidity and isotopes. A simple Rayleigh distillation model was not obeyed, instead the importance of rainfall re-evaporation in generating the highly depleted signatures was demonstrated. These data potentially provide a useful tool for evaluating model parameterizations in monsoonal regions as they demonstrate relationships with precipitation processes that cannot be observed with

  13. Cellulose acetate-based SiO2/TiO2 hybrid microsphere composite aerogel films for water-in-oil emulsion separation

    Science.gov (United States)

    Yang, Xue; Ma, Jianjun; Ling, Jing; Li, Na; Wang, Di; Yue, Fan; Xu, Shimei

    2018-03-01

    The cellulose acetate (CA)/SiO2-TiO2 hybrid microsphere composite aerogel films were successfully fabricated via water vapor-induced phase inversion of CA solution and simultaneous hydrolysis/condensation of 3-aminopropyltrimethoxysilane (APTMS) and tetrabutyl titanate (TBT) at room temperature. Micro-nano hierarchical structure was constructed on the surface of the film. The film could separate nano-sized surfactant-stabilized water-in-oil emulsions only under gravity. The flux of the film for the emulsion separation was up to 667 L m-2 h-1, while the separation efficiency was up to 99.99 wt%. Meanwhile, the film exhibited excellent stability during multiple cycles. Moreover, the film performed excellent photo-degradation performance under UV light due to the photocatalytic ability of TiO2. Facile preparation, good separation and potential biodegradation maked the CA/SiO2-TiO2 hybrid microsphere composite aerogel films a candidate in oil/water separation application.

  14. Propelling a water drop with the vapor-mediated Marangoni effect

    Science.gov (United States)

    Kim, Seungho; Kim, Ho-Young

    2013-11-01

    We show that a water drop on solid surfaces can be propelled just by placing a volatile alcohol drop nearby. It is found to be because the water-air interface near the alcohol drop mixes with alcohol vapor, thereby locally lowering the surface tension. The surface-tension-gradient induces the motion of the water drop, enabling the trajectory control of water drops through the motion of remote alcohol drops. This vapor-mediated Marangoni effect also gives rise to other interesting interfacial flow phenomena, such as nucleation of holes on a water film and ballooning of a water drop hanging from a syringe needle with the approach of an alcohol drop. We visualize such interfacial dynamics with a high-speed camera and rationalize their salient features by scaling analysis. This work was supported by the National Research Foundation of Korea (grant no. 2012-008023).

  15. Theoretical study of adsorption of water vapor on surface of metallic uranium

    CERN Document Server

    Xiong Bi Tao; Xue Wei Dong; Zhu Zheng He; Jiang Gang; Wang Hong Yan; Gao Tao

    2002-01-01

    According to the experimental data, there is an intermediate substance that formed in the initial stage of oxidation reaction when water vapor is absorbed onto the metallic uranium. The minimum energy of UOH sub 2 witch C sub 2 subupsilon configuration is obtained in the state of sup 5 A sub 1 by B3LYP method of the density function theory (DFT), which is consistent with that by statics of atoms and molecules reaction (AMRS) and group theory. The results from calculations indicate that the adsorption of water vapor on the metallic uranium is an exothermic reaction and that the adsorbed amount decreases with the elevated temperatures. The adsorptive heat at 1 atm is -205.4747 kJ centre dot mol sup - sup 1 , which indicates a typical chemical adsorption

  16. The ESA GOME-Evolution "Climate" water vapor product: a homogenized time series of H2O columns from GOME, SCIAMACHY, and GOME-2

    Science.gov (United States)

    Beirle, Steffen; Lampel, Johannes; Wang, Yang; Mies, Kornelia; Dörner, Steffen; Grossi, Margherita; Loyola, Diego; Dehn, Angelika; Danielczok, Anja; Schröder, Marc; Wagner, Thomas

    2018-03-01

    We present time series of the global distribution of water vapor columns over more than 2 decades based on measurements from the satellite instruments GOME, SCIAMACHY, and GOME-2 in the red spectral range. A particular focus is the consistency amongst the different sensors to avoid jumps from one instrument to another. This is reached by applying robust and simple retrieval settings consistently. Potentially systematic effects due to differences in ground pixel size are avoided by merging SCIAMACHY and GOME-2 observations to GOME spatial resolution, which also allows for a consistent treatment of cloud effects. In addition, the GOME-2 swath is reduced to that of GOME and SCIAMACHY to have consistent viewing geometries.Remaining systematic differences between the different sensors are investigated during overlap periods and are corrected for in the homogenized time series. The resulting Climate product v2.2 (https://doi.org/10.1594/WDCC/GOME-EVL_water_vapor_clim_v2.2" target="_blank">https://doi.org/10.1594/WDCC/GOME-EVL_water_vapor_clim_v2.2) allows the study of the temporal evolution of water vapor over the last 20 years on a global scale.

  17. PRINCÍPIOS BÁSICOS DE ESTERILIZAÇÃO A VAPOR

    Directory of Open Access Journals (Sweden)

    Celina Assumpção

    1973-02-01

    Full Text Available RESUMO O microrganismo é ser vivo que tem suas leis de crescimento e morte. Como todos os seres vivos, sua luta pela sobrevivência é grande e muitos são os meios com que a natureza os dotou para preservarem sua espécie diante de agentes nocivos. A sua resistência ao calor e umidade varia de acordo com as diferentes espécies, o que dificulta a sua destruição. Muitos foram os estudiosos que pesquizarem os meios pelos quais podem ser destruídos e conseguiram estabelecer pirincípios e normas a serem seguidos a fim de provocar a morte dos microrganismos pelo calor e umidade. Para se obter uma esterilização pelo vapor, é condição "sine qua non" que os princípios como de calor latente, contacto com o vapor, pressão atmosférica, Lei de Charles e outros sejam seguidos.

  18. Continuous Water Vapor Profiles from Operational Ground-Based Active and Passive Remote Sensors

    Science.gov (United States)

    Turner, D. D.; Feltz, W. F.; Ferrare, R. A.

    2000-01-01

    The Atmospheric Radiation Measurement program's Southern Great Plains Cloud and Radiation Testbed site central facility near Lamont, Oklahoma, offers unique operational water vapor profiling capabilities, including active and passive remote sensors as well as traditional in situ radiosonde measurements. Remote sensing technologies include an automated Raman lidar and an automated Atmospheric Emitted Radiance Interferometer (AERI), which are able to retrieve water vapor profiles operationally through the lower troposphere throughout the diurnal cycle. Comparisons of these two water vapor remote sensing methods to each other and to radiosondes over an 8-month period are presented and discussed, highlighting the accuracy and limitations of each method. Additionally, the AERI is able to retrieve profiles of temperature while the Raman lidar is able to retrieve aerosol extinction profiles operationally. These data, coupled with hourly wind profiles from a 915-MHz wind profiler, provide complete specification of the state of the atmosphere in noncloudy skies. Several case studies illustrate the utility of these high temporal resolution measurements in the characterization of mesoscale features within a 3-day time period in which passage of a dryline, warm air advection, and cold front occurred.

  19. CONDENSATION OF WATER VAPOR IN A VERTICAL TUBE CONDENSER

    Directory of Open Access Journals (Sweden)

    Jan Havlík

    2015-10-01

    Full Text Available This paper presents an analysis of heat transfer in the process of condensation of water vapor in a vertical shell-and-tube condenser. We analyze the use of the Nusselt model for calculating the condensation heat transfer coefficient (HTC inside a vertical tube and the Kern, Bell-Delaware and Stream-flow analysis methods for calculating the shell-side HTC from tubes to cooling water. These methods are experimentally verified for a specific condenser of waste process vapor containing air. The operating conditions of the condenser may be different from the assumptions adopted in the basic Nusselt theory. Modifications to the Nusselt condensation model are theoretically analyzed.

  20. Preparation of 2-in.-diameter (001) β-Ga2O3 homoepitaxial wafers by halide vapor phase epitaxy

    Science.gov (United States)

    Thieu, Quang Tu; Wakimoto, Daiki; Koishikawa, Yuki; Sasaki, Kohei; Goto, Ken; Konishi, Keita; Murakami, Hisashi; Kuramata, Akito; Kumagai, Yoshinao; Yamakoshi, Shigenobu

    2017-11-01

    The homoepitaxial growth of thick β-Ga2O3 layers on 2-in.-diameter (001) wafers was demonstrated by halide vapor phase epitaxy. Growth rates of 3 to 4 µm/h were confirmed for growing intentionally Si-doped n-type layers. A homoepitaxial layer with an average thickness and carrier concentration of 10.9 µm and 2.7 × 1016 cm-3 showed standard deviations of 1.8 µm (16.5%) and 0.5 × 1016 cm-3 (19.7%), respectively. Ni Schottky barrier diodes fabricated directly on a 5.3-µm-thick homoepitaxial layer with a carrier concentration of 3.4 × 1016 cm-3 showed reasonable reverse and forward characteristics, i.e., breakdown voltages above 200 V and on-resistances of 3.8-7.7 mΩ cm2 at room temperature.

  1. Effects of water vapor on flue gas conditioning in the electric fields with corona discharge.

    Science.gov (United States)

    Liqiang, Qi; Yajuan, Zhang

    2013-07-15

    Sulfur dioxide (SO2) removal via pulsed discharge nonthermal plasma in the absence of ammonia was investigated to determine how electrostatic precipitators (ESPs) can effectively collect particulate matter less than 2.5μm in diameter from flue gas. SO2 removal increased as water vapor concentration increased. In a wet-type plasma reactor, directing a gas-phase discharge plasma toward the water film surface significantly enhanced the liquid-phase oxidation of HSO3(-) to SO4(2-). Comparisons of various absorbents revealed that the hydroxyl radical is a key factor in plasma-induced liquid-phase reactions. The resistivity, size distribution, and cohesive force of fly ash at different water vapor contents were measured using a Bahco centrifuge, which is a dust electrical resistivity test instrument, as well as a cohesive force test apparatus developed by the researchers. When water vapor content increased by 5%, fly ash resistivity in flue gas decreased by approximately two orders of magnitude, adhesive force and size increased, and specific surface area decreased. Therefore, ESP efficiency increased. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols

    Science.gov (United States)

    Carter, Arlen F.; Allen, Robert J.; Mayo, M. Neale; Butler, Carolyn F.; Grossman, Benoist E.; Ismail, Syed; Grant, William B.; Browell, Edward V.; Higdon, Noah S.; Mayor, Shane D.; hide

    1994-01-01

    An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H2O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and greater than 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H2O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H2O absorption-line parameters were performed to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H2O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H2O radiosondes. The H2O distributions measured with the DIAL system differed by less than 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions.

  3. Partitioning Water Vapor and Carbon Dioxide Fluxes using Correlation Analysis

    Science.gov (United States)

    Scanlon, T. M.

    2008-12-01

    A variety of methods are currently available to partition water vapor fluxes (into components of transpiration and direct evaporation) and carbon dioxide fluxes (into components of photosynthesis and respiration), using chambers, isotopes, and regression modeling approaches. Here, a methodology is presented that accounts for correlations between high-frequency measurements of water vapor (q) and carbon dioxide (c) concentrations being influenced by their non-identical source-sink distributions and the relative magnitude of their constituent fluxes. Flux-variance similarity assumptions are applied separately to the stomatal and the non-stomatal exchange, and the flux components are identified by considering the q-c correlation. Water use efficiency for the vegetation, and how it varies with respect to vapor pressure deficit, is the only input needed for this approach that uses standard eddy covariance measurements. The method is demonstrated using data collected over a corn field throughout a growing season. In particular, the research focuses on the partitioning of the water flux with the aim of improving how direct evaporation is handled in soil-vegetation- atmosphere transfer models over the course of wetting and dry-down cycles.

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

    Science.gov (United States)

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

    2005-11-15

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

  5. Waste storage in the vadose zone affected by water vapor condensation and leaching

    International Nuclear Information System (INIS)

    Cary, J.W.; Gee, G.W.; Whyatt, G.A.

    1990-08-01

    One of the major concerns associated with waste storage in the vadose zone is that toxic materials may somehow be leached and transported by advecting water down to the water table and reach the accessible environment through either a well or discharge to a river. Consequently, care is taken to provide barriers over and around the storage sites to reduce contact between infiltrating water and the buried waste form. In some cases, it is important to consider the intrusion of water vapor as well as water in the liquid phase. Water vapor diffuses through porous material along vapor pressure gradients. A slightly low temperature, or the presence of water-soluble components in the waste, favors water condensation resulting in leaching of the waste form and advection of water-soluble components to the water table. A simple analysis is presented that allows one to estimate the rate of vapor condensation as a function of waste composition and backfill materials. An example using a waste form surrounded by concrete and gravel layers is presented. The use of thermal gradients to offset condensation effects of water-soluble components in the waste form is discussed. Thermal gradients may be controlled by design factors that alter the atmospheric energy exchange across the soil surface or that interrupt the geothermal heat field. 7 refs., 2 figs., 1 tab

  6. Constraining the 0-20 km Vertical Profile of Water Vapor in the Martian Atmosphere with MGS-TES Limb Sounding

    Science.gov (United States)

    McConnochie, T. H.; Smith, M. D.; McDonald, G. D.

    2016-12-01

    water vapor profile results that we obtain by: 1) investigating simplified parameterizations of the profile; 2) addressing Nyquist-frequency correlated-noise in the TES spectra; 3) combining nadir and limb sounding to better resolve the bottom scale height.

  7. Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model.

    Science.gov (United States)

    Bauer, Brad A; Patel, Sandeep

    2009-08-28

    We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of T(c)=623 K, rho(c)=0.351 g/cm(3), and P(c)=250.9 atm, which are in good agreement with experimental values of T(c)=647.1 K, rho(c)=0.322 g/cm(3), and P(c)=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (T(c)=631 K and rho(c)=0.308 g/cm(3)). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300-450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase

  8. Sensitive coating for water vapors detection based on thermally sputtered calcein thin films.

    Science.gov (United States)

    Kruglenko, I; Shirshov, Yu; Burlachenko, J; Savchenko, A; Kravchenko, S; Manera, M G; Rella, R

    2010-09-15

    In this paper the adsorption properties of thermally sputtered calcein thin films towards water and other polar molecules vapors are studied by different characterization techniques: quartz crystal microbalance, surface plasmon resonance and visible spectroscopy. Sensitivity of calcein thin films to water vapors resulted much higher as compared with those of a number of dyes whose structure was close to that of calcein. All types of sensors with calcein coatings have demonstrated linear concentration dependences in the wide range of water vapor pressure from low concentrations up to 27,000 ppm (close to saturation). At higher concentrations of water vapor all sensors demonstrate the abrupt increase of the response (up to two orders). A theoretical model is advanced explaining the adsorption properties of calcein thin films taking into account their chemical structure and peculiarities of molecular packing. The possibility of application of thermally sputtered calcein films in sensing technique is discussed. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  9. Rapid extraction of uranium from sea water using Fe{sub 3}O{sub 4} and humic acid coated Fe{sub 3}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Singhal, Pallavi, E-mail: psinghal@barc.gov.in [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Jha, Sanjay K. [Homi Bhabha National Institute, Mumbai 400094 (India); Health Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Pandey, Shailaja P. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Neogy, Suman [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2017-08-05

    Highlights: • Uranium extraction using Fe{sub 3}O{sub 4} and HA coated Fe{sub 3}O{sub 4} NPs has been demonstrated. • Result indicates uranium extraction from both water and sea water matrix. • With increase in HA coating uranium extraction increases. • Fe{sub 3}O{sub 4}/HA 1 is the best material among synthesized one for uranium extraction. - Abstract: Uranium is one of the most toxic elements present in the environment and a number of methods have been developed for its extraction. Herein we have demonstrated a new method using magnetic nanoparticles (NPs) that can be used for uranium extraction from water and sea water matrix. Fe{sub 3}O{sub 4} and humic acid (HA) coated Fe{sub 3}O{sub 4} NPs with different amount of HA coating were synthesized and uranium sorption from water and sea water matrix was demonstrated. It was observed that sorption increases with increase in amount of HA coating. NPs settlement in presence of magnetic field was monitored where only bare Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}/HA 1 NPs settles while no settlement was observed for Fe{sub 3}O{sub 4}/HA 2 and Fe{sub 3}O{sub 4}/HA 3 NPs. Considering both sorption and particle separation from the matrix Fe{sub 3}O{sub 4}/HA 1 NPs are the best among synthesized ones with maximum sorption capacity of 10.5 mg of U/g of NPs. The results presented here reveal the exceptional potential of magnetic NPs and functionalized magnetic NPs for environmental remediation of uranium and to extract uranium from sea water on which to the best of our knowledge no report is available till now.

  10. The effect of molten salt on high temperature behavior of stainless steel and titanium alloy with the presence of water vapor

    Science.gov (United States)

    Baharum, Azila; Othman, Norinsan Kamil; Salleh, Emee Marina

    2018-04-01

    The high temperature oxidation experiment was conducted to study the behavior of titanium alloy Ti6A14V and stainless steel 316 in Na2SO4-50%NaCl + Ar-20%O2 (molten salt) and Na2SO4-50%NaCl + Ar-20%O2 + 12% H2O (molten salt + water vapor) environment at 900°C for 30 hours using horizontal tube furnace. The sample then was investigated using weight change measurement analysis and X-ray diffraction (XRD) analysis to study the weight gained and the phase oxidation that occurred. The weight gained of the titanium alloy was higher in molten salt environment compared to stainless steel due to the rapid growth in the oxide scale but showed almost no change of weight gained upon addition of water vapor. This is due to the alloy was fully oxidized. Stainless steel showed more protection and better effect in molten salt environment compared to mixed environment showed by slower weight gain and lower oxidation rate. Meanwhile, the phase oxidation test of the samples showed that the titanium alloy consist of multi oxide layer of rutile (TiO2) and Al2O3 on the surface of the exposed sample. While stainless steel show the formation of both protective Cr-rich oxide and non-protective Fe-rich oxide layer. This can be concluded that stainless steel is better compared to Ti alloy due to slow growing of chromia oxide. Therefore it is proven that stainless steel has better self-protection upon high temperature exposure.

  11. Relationship between changes in the upper and lower tropospheric water vapor: A revisit

    Science.gov (United States)

    Yang, M.; Sun, D. Z.; Zhang, G. J.

    2017-12-01

    Upper tropospheric water vapor response to enhanced greenhouse gas forcing is as important as the lower tropospheric water vapor response in determining climate sensitivity. Early studies using older versions of climate models have suggested that the upper- and lower-troposphere water vapor changes are more strongly coupled in the climate models than in the observations. Here we reexamine this issue using a state-of-the-art climate model—the NCAR community model CAM5. Specifically, we have calculated the correlations between interannual variations of specific humidity in all levels of the troposphere with that at the surface in CAM5 and in the observations (as represented by the updated ERA-Interim and NCEP reanalysis). It is found that the previously noted biases in how strongly upper tropospheric water vapor and lower troposphere water vapor are linked still exist in CAM5—the change in the tropical averaged upper tropospheric water vapor is more strongly correlated with the change in the surface. However, this bias disappears in the averaged correlation obtained by averaging the point-by-point correlations over the tropics. The spatial pattern of the point-by-point correlations reveals that the better agreement between the model and the observations is related to the opposite model biases in different regions: the correlation is weaker in the model in the western Pacific, but stronger in the central and eastern Pacific. Further analysis of precipitation fields suggests that the weaker (stronger) coupling between tropospheric water vapor and surface moisture over western (central-eastern) Pacific in model is related to weaker (stronger) simulated convective activities in these regions. More specifically, during El Nino, the model has excessive deep convection in the central Pacific, but too littler deep convection in western Pacific. Implications of the results are discussed in the context of climate change as well as in the context of how to improve the model

  12. Comparing electrical characteristics of in situ and ex situ Al2O3/GaN interfaces formed by metalorganic chemical vapor deposition

    Science.gov (United States)

    Chan, Silvia H.; Bisi, Davide; Tahhan, Maher; Gupta, Chirag; DenBaars, Steven P.; Keller, Stacia; Zanoni, Enrico; Mishra, Umesh K.

    2018-04-01

    Al2O3/n-GaN MOS-capacitors grown by metalorganic chemical vapor deposition with in-situ- and ex-situ-formed Al2O3/GaN interfaces were characterized. Capacitors grown entirely in situ exhibited ˜4 × 1012 cm-2 fewer positive fixed charges and up to ˜1 × 1013 cm-2 eV-1 lower interface-state density near the band-edge than did capacitors with ex situ oxides. When in situ Al2O3/GaN interfaces were reformed via the insertion of a 10-nm-thick GaN layer, devices exhibited behavior between the in situ and ex situ limits. These results illustrate the extent to which an in-situ-formed dielectric/GaN gate stack improves the interface quality and breakdown performance.

  13. Nanoscale leakage current measurements in metal organic chemical vapor deposition crystalline SrTiO3 films

    International Nuclear Information System (INIS)

    Rozier, Y.; Gautier, B.; Hyvert, G.; Descamps, A.; Plossu, C.; Dubourdieu, C.; Ducroquet, F.

    2009-01-01

    The properties of SrTiO 3 thin films, grown by liquid injection metal organic chemical vapor deposition on Si/SiO 2 , using a mixture of precursors, have been investigated at the nanoscale using an Atomic Force Microscope in the so-called Conductive Atomic Force Microscopy mode. Maps of the leakage currents with a nanometric resolution have been obtained on films elaborated at different temperatures and stoichiometries in order to discriminate the role of each parameter on the onset of leakage currents in the resulting layers. It appears that the higher the deposition temperature, the higher the leakage currents of the films. The mapping with a nanometric precision allows to show a heterogeneous behaviour of the surface with leaky grains and insulating boundaries. The study of films elaborated at the same temperature with different compositions supports the assumption that the leakage currents on Ti-rich layers are far higher than on Sr-rich layers

  14. ZnO:Al Thin Film Gas Sensor for Detection of Ethanol Vapor

    Directory of Open Access Journals (Sweden)

    Min Hsiung Hon

    2006-10-01

    Full Text Available The ZnO:Al thin films were prepared by RF magnetron sputtering on Si substrateusing Pt as interdigitated electrodes. The structure was characterized by XRD and SEManalyses, and the ethanol vapor gas sensing as well as electrical properties have beeninvestigated and discussed. The gas sensing results show that the sensitivity for detecting400 ppm ethanol vapor was ~20 at an operating temperature of 250°C. The high sensitivity,fast recovery, and reliability suggest that ZnO:Al thin film prepared by RF magnetronsputtering can be used for ethanol vapor gas sensing.

  15. Combined ground- and satellite-based profiling of temperature and water vapor

    International Nuclear Information System (INIS)

    Stankov, B.B.; Westwater, E.R.; Snider, J.B.; Churnside, J.H.

    1994-01-01

    The fusion or integration of meteorological and radiative data from a range of instrumentation into a representative picture of temperature, water vapor, and clouds over a CART domain will be a challenging task for four-dimensional data assimilation models. In the work reported here, we have summarized work supported by DOE's algorithm development program including combined RASS and TIROS Operational Vertical Sounder (TOVS) temperature sensing, water vapor profiles from dual-channel radiometers, and neural network radiometric temperature retrievals

  16. In Situ Water Vapor Measurements Using Coupled UV Fragment Fluorescence/Absorption Spectroscopy in Support of CRYSTAL-FACE

    Science.gov (United States)

    Anderson, James G.

    2004-01-01

    Understanding the coupling of dynamics, chemistry, and radiation within the context of the NASA Earth Science Enterprise (ESE) and the national Climate Change Science Program (CCSP) requires, as a first-order priority, high spatial resolution, high-accuracy observations of water in its various phases. Given the powerful diagnostic importance of the condensed phases of water for dynamics and the impact of phase changes in water on the radiation field, the accurate, in situ observation of water vapor is of central importance to CRYSTAL FACE (CF). This is clear both from the defined scientific objectives of the NRA and from developments in the coupled fields of stratosphere/troposphere exchange, cirrus cloud formation/removal and mechanisms for the distribution of water vapor in the middle/upper troposphere. Accordingly, we were funded under NASA Grant NAG5-11548 to perform the following tasks for the CF mission: 1. Prepare the water vapor instrument for integration into the WB57F and test flights scheduled for Spring 2002. 2. Calibrate and prepare the water vapor instrument for the Summer 2002 CF science flights based in Jacksonville, Florida. 3. Provide both science and engineering support for the above-mentioned efforts. 4. Analyze and interpret the CF data in collaboration with other mission scientists. 5. Attend the science workshop in Spring 2003. 6. Publish the data and analysis in peer-reviewed journals.

  17. Temperature/pressure and water vapor sounding with microwave spectroscopy

    Science.gov (United States)

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

    1992-01-01

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

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

    Science.gov (United States)

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

    2018-05-01

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

  19. Relating tropical ocean clouds to moist processes using water vapor isotope measurements

    Directory of Open Access Journals (Sweden)

    J. Lee

    2011-01-01

    Full Text Available We examine the co-variations of tropospheric water vapor, its isotopic composition and cloud types and relate these distributions to tropospheric mixing and distillation models using satellite observations from the Aura Tropospheric Emission Spectrometer (TES over the summertime tropical ocean. Interpretation of these process distributions must take into account the sensitivity of the TES isotope and water vapor measurements to variations in cloud, water, and temperature amount. Consequently, comparisons are made between cloud-types based on the International Satellite Cloud Climatology Project (ISSCP classification; these are clear sky, non-precipitating (e.g., cumulus, boundary layer (e.g., stratocumulus, and precipitating clouds (e.g. regions of deep convection. In general, we find that the free tropospheric vapor over tropical oceans does not strictly follow a Rayleigh model in which air parcels become dry and isotopically depleted through condensation. Instead, mixing processes related to convection as well as subsidence, and re-evaporation of rainfall associated with organized deep convection all play significant roles in controlling the water vapor distribution. The relative role of these moisture processes are examined for different tropical oceanic regions.

  20. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Turner, David, D.; Ferrare, Richard, A.

    2011-07-06

    The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

  1. Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available Fluorine-containing hydrophobic mesoporous material (MFS with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1 and 0.74 cm3 g−1 with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1 at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

  2. Summer carbon dioxide and water vapor fluxes across a range of northern peatlands

    Science.gov (United States)

    Humphreys, Elyn R.; Lafleur, Peter M.; Flanagan, Lawrence B.; Hedstrom, Newell; Syed, Kamran H.; Glenn, Aaron J.; Granger, Raoul

    2006-12-01

    Northern peatlands are a diverse group of ecosystems varying along a continuum of hydrological, chemical, and vegetation gradients. These ecosystems contain about one third of the global soil carbon pool, but it is uncertain how carbon and water cycling processes and response to climate change differ among peatland types. This study examines midsummer CO2 and H2O fluxes measured using the eddy covariance technique above seven northern peatlands including a low-shrub bog, two open poor fens, two wooded moderately rich fens, and two open extreme-rich fens. Gross ecosystem production and ecosystem respiration correlated positively with vegetation indices and with each other. Consequently, 24-hour net ecosystem CO2 exchange was similar among most of the sites (an average net carbon sink of 1.5 ± 0.2 g C m-2 d-1) despite large differences in water table depth, water chemistry, and plant communities. Evapotranspiration was primarily radiatively driven at all sites but a decline in surface conductance with increasing water vapor deficit indicated physiological restrictions to transpiration, particularly at the peatlands with woody vegetation and less at the peatlands with 100% Sphagnum cover. Despite these differences, midday evapotranspiration ranged only from 0.21 to 0.34 mm h-1 owing to compensation among the factors controlling evapotranspiration. Water use efficiency varied among sites primarily as a result of differences in productivity and plant functional type. Although peatland classification includes a great variety of ecosystem characteristics, peatland type may not be an effective way to predict the magnitude and characteristics of midsummer CO2 and water vapor exchanges.

  3. Catalyst-free vapor-phase transport growth of vertically aligned ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-03-15

    ZnO nanostructures are expected to pave the way for many interesting applications in optoelectronics, spin electronics gas sensor technology and biomedicine. Fabrication methods, especially for nanorods have been based mostly on catalyst-assisted growth methods that employ metal-organic sources and other contaminating agents like graphite to grow ZnO nanorods at relatively high temperatures. We report on the growth of ZnO nanorods on 6H-SiC and (11-20)Al{sub 2}O{sub 3} using purely elemental sources, without catalysis and at relatively low temperatures and growth pressure in a specially designed vapor-phase transport system. ZnO nanorods with widths of 80-900 nm and lengths of 4-12 {mu}m were obtained. Nanorod concentrations of up to 10{sup 9} cm{sup -2} with homogenous luminescence and high purity were noted. (orig.)

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

    Science.gov (United States)

    Ponsardin, Patrick; Browell, Edward V.

    1995-01-01

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

  5. Assessment of water vapor content from MIVIS TIR data

    Directory of Open Access Journals (Sweden)

    V. Tramutoli

    2006-06-01

    Full Text Available The main objective of land remotely sensed images is to derive biological, chemical and physical parameters by inverting sample sets of spectral data. For the above aim hyperspectral scanners on airborne platform are a powerful remote sensing instrument for both research and environmental applications because of their spectral resolution and the high operability of the platform. Fine spectral information by MIVIS (airborne hyperspectral scanner operating in 102 channels ranging from VIS to TIR allows researchers to characterize atmospheric parameters and their effects on measured data which produce undesirable features on surface spectral signatures. These effects can be estimated (and remotely sensed radiances corrected if atmospheric spectral transmittance is known at each image pixel. Usually ground-based punctual observations (atmospheric sounding balloons, sun photometers, etc. are used to estimate the main physical parameters (like water vapor and temperature profiles which permit us to estimate atmospheric spectral transmittance by using suitable radiative transfer model and a specific (often too strong assumption which enable atmospheric properties measured only in very few points to be extended to the whole image. Several atmospheric gases produce observable absorption features, but only water vapor strongly varies in time and space. In this work the authors customize a self-sufficient «split-window technique» to derive (at each image pixel atmospheric total columnar water vapor content (TWVC using only MIVIS data collected by the fourth MIVIS spectrometer (Thermal Infrared band. MIVIS radiances have been simulated by means of MODTRAN4 radiative transfer code and the coefficients of linear regression to estimate TWVC from «split-windows» MIVIS radiances, based on 450 atmospheric water vapor profiles obtained by radiosonde data provided by NOAANESDIS. The method has been applied to produce maps describing the spatial variability of

  6. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Science.gov (United States)

    Periolatto, M.; Sangermano, M.; Spena, P. Russo

    2016-05-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  7. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Periolatto, M.; Spena, P. Russo [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano (Italy); Sangermano, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino (Italy)

    2016-05-18

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  8. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    International Nuclear Information System (INIS)

    Periolatto, M.; Spena, P. Russo; Sangermano, M.

    2016-01-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  9. Flame-Sprayed Y2O3 Films with Metal-EDTA Complex Using Various Cooling Agents

    Science.gov (United States)

    Komatsu, Keiji; Toyama, Ayumu; Sekiya, Tetsuo; Shirai, Tomoyuki; Nakamura, Atsushi; Toda, Ikumi; Ohshio, Shigeo; Muramatsu, Hiroyuki; Saitoh, Hidetoshi

    2017-01-01

    In this study, yttrium oxide (Y2O3) films were synthesized from a metal-ethylenediaminetetraacetic (metal-EDTA) complex by employing a H2-O2 combustion flame. A rotation apparatus and various cooling agents (compressed air, liquid nitrogen, and atomized purified water) were used during the synthesis to control the thermal history during film deposition. An EDTA·Y·H complex was prepared and used as the staring material for the synthesis of Y2O3 films with a flame-spraying apparatus. Although thermally extreme environments were employed during the synthesis, all of the obtained Y2O3 films showed only a few cracks and minor peeling in their microstructures. For instance, the Y2O3 film synthesized using the rotation apparatus with water atomization units exhibited a porosity of 22.8%. The maximum film's temperature after deposition was 453 °C owing to the high heat of evaporation of water. Cooling effects of substrate by various cooling units for solidification was dominated to heat of vaporization, not to unit's temperatures.

  10. Deuterium- and 18O-content in the cooling water of power station cooling towers

    International Nuclear Information System (INIS)

    Heimbach, H.; Dongmann, G.

    1976-09-01

    The 0-18/0-16 and D/H isotope ratios of water from two different cooling towers were determined by mass spectrometry. The observed isotope fractionation corresponds to that known from natural evaporation or transpiration processes: cooling tower I: delta(D) = 46.8 per thousand, delta( 18 O) = 7.6 per thousand cooling tower II: delta(D) = 33.9 per thousand delta( 18 O) = 5.7 per thousand Evaluation of simple compartment models of a cooling tower and a distillation device suggests that there exists some isotope discrimination within the open trickling unit of a cooling tower analogous to that in a rectification column. In a real cooling tower, however, this effect is compensated largely by the recycling of the cooling water, resulting only in a small enrichment of the heavy isotopes. This can be understood as the result of three partial effects: 1) a fractionation in the vapor pressure equilibrium, 2) a kinetic effect due to diffusion of the water vapor into a turbulent atmosphere, and 3) an exchange effect which is proportional to relative humidity. This low enrichment of the heavy isotope excludes the technical use of cooling towers as isotope separation devices. (orig.) [de

  11. Structure and Dynamics in Formamide-(H2O)3: A Water Pentamer Analogue.

    Science.gov (United States)

    Blanco, Susana; Pinacho, Pablo; López, Juan Carlos

    2017-12-21

    Water self-association dominates the formation of microsolvated molecular clusters which may give rise to complex structures resembling those of pure water clusters. We present a rotational study of the complex formamide-(H 2 O) 3 formed in a supersonic jet and several monosubstituted isotopologues. Formamide and water molecules form a four-body sequential cycle through N-H···O, O-H···O, and O-H···O═C hydrogen bonds, resulting in a chiral structure with a nonplanar skeleton that can be overlapped to that of water pentamer. The analysis of the 14 N-nucleus quadrupole coupling effects shows the depletion of the electron density of the N atom lone pair with respect to the bare formamide that affects the amide group C-N and C═O distances. The study of the observed tunneling doublets shows that formamide-(H 2 O) 3 follows a path to invert its structure driven by the flipping of water subunits and passing through successive nonplanar configurations, a motion reminiscent of the pseudorotation of water pentamer.

  12. Volatilized tritiated water vapor in the vicinity of exposed tritium contaminated groundwater

    International Nuclear Information System (INIS)

    Dunn, D.L.; Carlton, B.; Hunter, C.; McAdams, T.

    1994-01-01

    Water vapor tritium concentrations in air above a known source of tritiated water can be estimated. Estimates should account for the mechanisms of evaporation and condensation at the water surface and water species exchange, and are typically applicable under a broad range of wind, temperature and humidity conditions. An estimate of volatilized tritium water vapor was made for a known outcropping of tritium contaminated groundwater at the Savannah River Site (SRS) old F-Area effluent stream. In order to validate this estimate and the associated dose calculation, sampling equipment was fabricated, tested, and installed at the effluent stream. The estimate and the dose calculation were confirmed using data from samples collected

  13. Carbon-Electrode-Tailored All-Inorganic Perovskite Solar Cells To Harvest Solar and Water-Vapor Energy.

    Science.gov (United States)

    Duan, Jialong; Hu, Tianyu; Zhao, Yuanyuan; He, Benlin; Tang, Qunwei

    2018-05-14

    Moisture is the worst enemy for state-of-the-art perovskite solar cells (PSCs). However, the flowing water vapor within nanoporous carbonaceous materials can create potentials. Therefore, it is a challenge to integrate water vapor and solar energies into a single PSC device. We demonstrate herein all-inorganic cesium lead bromide (CsPbBr 3 ) solar cells tailored with carbon electrodes to simultaneously harvest solar and water-vapor energy. Upon interfacial modification and plasma treatment, the bifunctional PSCs yield a maximum power conversion efficiency up to 9.43 % under one sun irradiation according to photoelectric conversion principle and a power output of 0.158 μW with voltage of 0.35 V and current of 0.45 μA in 80 % relative humidity through the flowing potentials at the carbon/water interface. The initial efficiency is only reduced by 2 % on exposing the inorganic PSC with 80 % humidity over 40 days. The successful realization of physical proof-of-concept multi-energy integrated solar cells provides new opportunities of maximizing overall power output. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. SEPARATION OF WATER VAPORS FROM AIR BY SORPTION ON SOME COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    OANA HAUTĂ

    2014-01-01

    Full Text Available This work presents an experimental investigation of the kinetics of water vapor sorption on two composites synthesized by impregnating activated carbon and activated alumina respectively with lithium bromide (named as MCA2 and MCC2 respectively. The obtained results showed an increase in water amount adsorbed on both composite materials. Due to different chemical natures of the host matrices, the water sorption kinetics on MCC2 is faster compared to that of MCA2. The presence of calcium chloride instead of lithium bromide in alumina pores will determine a shorter breakthrough time and a higher adsorption rate of water vapors.

  15. A Water Vapor Differential Absorption LIDAR Design for Unpiloted Aerial Vehicles

    Science.gov (United States)

    DeYoung, Russell J.; Mead, Patricia F.

    2004-01-01

    This system study proposes the deployment of a water vapor Differential Absorption LIDAR (DIAL) system on an Altair unmanned aerial vehicle (UAV) platform. The Altair offers improved payload weight and volume performance, and longer total flight time as compared to other commercial UAV's. This study has generated a preliminary design for an Altair based water vapor DIAL system. The design includes a proposed DIAL schematic, a review of mechanical challenges such as temperature and humidity stresses on UAV deployed DIAL systems, an assessment of the available capacity for additional instrumentation (based on the proposed design), and an overview of possible weight and volume improvements associated with the use of customized electronic and computer hardware, and through the integration of advanced fiber-optic and laser products. The results of the study show that less than 17% of the available weight, less than 19% of the volume capacity, and approximately 11% of the electrical capacity is utilized by the proposed water vapor DIAL system on the Altair UAV.

  16. Hierarchical FeTiO3-TiO2 hollow spheres for efficient simulated sunlight-driven water oxidation.

    Science.gov (United States)

    Han, Taoran; Chen, Yajie; Tian, Guohui; Wang, Jian-Qiang; Ren, Zhiyu; Zhou, Wei; Fu, Honggang

    2015-10-14

    Oxygen generation is the key step for the photocatalytic overall water splitting and considered to be kinetically more challenging than hydrogen generation. Here, an effective water oxidation catalyst of hierarchical FeTiO3-TiO2 hollow spheres are prepared via a two-step sequential solvothermal processes and followed by thermal treatment. The existence of an effective heterointerface and built-in electric field in the surface space charge region in FeTiO3-TiO2 hollow spheres plays a positive role in promoting the separation of photoinduced electron-hole pairs. Surface photovoltage, transient-state photovoltage, fluorescence and electrochemical characterization are used to investigate the transfer process of photoinduced charge carriers. The photogenerated charge carriers in the hierarchical FeTiO3-TiO2 hollow spheres with a proper molar ratio display much higher separation efficiency and longer lifetime than those in the FeTiO3 alone. Moreover, it is suggested that the hierarchical porous hollow structure can contribute to the enhancement of light utilization, surface active sites and material transportation through the framework walls. This specific synergy significantly contributes to the remarkable improvement of the photocatalytic water oxidation activity of the hierarchical FeTiO3-TiO2 hollow spheres under simulated sunlight (AM1.5).

  17. Atmospheric Pre-Corrected Differential Absorption Techniques to Retrieve Columnar Water Vapor: Theory and Simulations

    Science.gov (United States)

    Borel, Christoph C.; Schlaepfer, Daniel

    1996-01-01

    Two different approaches exist to retrieve columnar water vapor from imaging spectrometer data: (1) Differential absorption techniques based on: (a) Narrow-Wide (N/W) ratio between overlapping spectrally wide and narrow channels; (b) Continuum Interpolated Band Ratio (CIBR) between a measurement channel and the weighted sum of two reference channels. (2) Non-linear fitting techniques which are based on spectral radiative transfer calculations. The advantage of the first approach is computational speed and of the second, improved retrieval accuracy. Our goal was to improve the accuracy of the first technique using physics based on radiative transfer. Using a modified version of the Duntley equation, we derived an "Atmospheric Pre-corrected Differential Absorption" (APDA) technique and described an iterative scheme to retrieve water vapor on a pixel-by-pixel basis. Next we compared both, the CIBR and the APDA using the Duntley equation for MODTRAN3 computed irradiances, transmissions and path radiance (using the DISORT option). This simulation showed that the CIBR is very sensitive to reflectance effects and that the APDA performs much better. An extensive data set was created with the radiative transfer code 6S over 379 different ground reflectance spectra. The calculated relative water vapor error was reduced significantly for the APDA. The APDA technique had about 8% (vs. over 35% for the CIBR) of the 379 spectra with a relative water vapor error of greater than +5%. The APDA has been applied to 1991 and 1995 AVIRIS scenes which visually demonstrate the improvement over the CIBR technique.

  18. Atmospheric pre-corrected differential absorption techniques to retrieve columnar water vapor: Theory and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Borel, C.C.; Schlaepfer, D.

    1996-03-01

    Two different approaches exist to retrieve columnar water vapor from imaging spectrometer data: (1) Differential absorption techniques based on: (a) Narrow-Wide (N/W) ratio between overlapping spectrally wide and narrow channels (b) Continuum Interpolated Band Ratio (CIBR) between a measurement channel and the weighted sum of two reference channels; and (2) Non-linear fitting techniques which are based on spectral radiative transfer calculations. The advantage of the first approach is computational speed and of the second, improved retrieval accuracy. Our goal was to improve the accuracy of the first technique using physics based on radiative transfer. Using a modified version of the Duntley equation, we derived an {open_quote}Atmospheric Pre-corrected Differential Absorption{close_quote} (APDA) technique and described an iterative scheme to retrieve water vapor on a pixel-by-pixel basis. Next we compared both, the CIBR and the APDA using the Duntley equation for MODTRAN3 computed irradiances, transmissions and path radiance (using the DISORT option). This simulation showed that the CIBR is very sensitive to reflectance effects and that the APDA performs much better. An extensive data set was created with the radiative transfer code 6S over 379 different ground reflectance spectra. The calculated relative water vapor error was reduced significantly for the APDA. The APDA technique had about 8% (vs. over 35% for the CIBR) of the 379 spectra with a relative water vapor error of greater than {+-}5%. The APDA has been applied to 1991 and 1995 AVIRIS scenes which visually demonstrate the improvement over the CIBR technique.

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

    Science.gov (United States)

    Wheeler, Tobias D; Stroock, Abraham D

    2009-07-07

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

  20. Climatic Analysis of Oceanic Water Vapor Transports Based on Satellite E-P Datasets

    Science.gov (United States)

    Smith, Eric A.; Sohn, Byung-Ju; Mehta, Vikram

    2004-01-01

    Understanding the climatically varying properties of water vapor transports from a robust observational perspective is an essential step in calibrating climate models. This is tantamount to measuring year-to-year changes of monthly- or seasonally-averaged, divergent water vapor transport distributions. This cannot be done effectively with conventional radiosonde data over ocean regions where sounding data are generally sparse. This talk describes how a methodology designed to derive atmospheric water vapor transports over the world oceans from satellite-retrieved precipitation (P) and evaporation (E) datasets circumvents the problem of inadequate sampling. Ultimately, the method is intended to take advantage of the relatively complete and consistent coverage, as well as continuity in sampling, associated with E and P datasets obtained from satellite measurements. Independent P and E retrievals from Special Sensor Microwave Imager (SSM/I) measurements, along with P retrievals from Tropical Rainfall Measuring Mission (TRMM) measurements, are used to obtain transports by solving a potential function for the divergence of water vapor transport as balanced by large scale E - P conditions.

  1. alpha-Fe2O3 versus beta-Fe2O3: Controlling the Phase of the Transformation Product of epsilon-Fe2O3 in the Fe2O3/SiO2 System

    Czech Academy of Sciences Publication Activity Database

    Brázda, Petr; Kohout, J.; Bezdička, Petr; Kmjec, T.

    2014-01-01

    Roč. 14, č. 3 (2014), s. 1039-1046 ISSN 1528-7483 R&D Projects: GA ČR GAP204/10/0035 Institutional support: RVO:61388980 Keywords : CHEMICAL-VAPOR-DEPOSITION * OXIDE THIN-FILMS * X-RAY * GAMMA-FE2O3 NANOPARTICLES * THERMAL-DECOMPOSITION Subject RIV: CA - Inorganic Chemistry Impact factor: 4.891, year: 2014

  2. Effects of convective ice evaporation on interannual variability of tropical tropopause layer water vapor

    Science.gov (United States)

    Ye, Hao; Dessler, Andrew E.; Yu, Wandi

    2018-04-01

    Water vapor interannual variability in the tropical tropopause layer (TTL) is investigated using satellite observations and model simulations. We break down the influences of the Brewer-Dobson circulation (BDC), the quasi-biennial oscillation (QBO), and the tropospheric temperature (ΔT) on TTL water vapor as a function of latitude and longitude using a two-dimensional multivariate linear regression. This allows us to examine the spatial distribution of the impact of each process on TTL water vapor. In agreement with expectations, we find that the impacts from the BDC and QBO act on TTL water vapor by changing TTL temperature. For ΔT, we find that TTL temperatures alone cannot explain the influence. We hypothesize a moistening role for the evaporation of convective ice from increased deep convection as the troposphere warms. Tests using a chemistry-climate model, the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM), support this hypothesis.

  3. Improved lifetime of chitosan film in converting water vapor to electrical power by adding carboxymethyl cellulose

    Science.gov (United States)

    Nasution, T. I.; Balyan, M.; Nainggolan, I.

    2018-02-01

    A Water vapor cell based on chitosan film has been successfully fabricated in film form to convert water vapor to electrical power. In order to improve the lifetime of water vapor cell, Carboxymethyl Cellulose (CMC) was added into 1% chitosan solution within concentration variations of 0.01, 0.05, 0.1 and 0.5%. The result showed that the lifetime of water vapor cell increased higher by adding the higher concentration of Carboxymethyl cellulose. The highest lifetime was evidenced by adding 0.5%CMC which maintained for 48 weeks. However, the average electrical power became lower to 4.621 µW. This electrical power lower than the addition of 0.1%CMC which maintained for 5.167 µW. While, the lifetime of chitosan-0.1%CMC film of 44 weeks is shorter compared to chitosan-0.5%CMC film. Based on FTIR characterization, it was founded that the chitosan structure did not change until the addition of 0.1%CMC. This caused the electrical power of water vapor cell degenerated. Therefore, chitosan-0.5%CMC film has excellent lifetime in converting water vapor to electrical power.

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

    International Nuclear Information System (INIS)

    Knox, R.J.

    1975-01-01

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

  5. Influence of absorption by environmental water vapor on radiation transfer in wildland fires

    Science.gov (United States)

    D. Frankman; B. W. Webb; B. W. Butler

    2008-01-01

    The attenuation of radiation transfer from wildland flames to fuel by environmental water vapor is investigated. Emission is tracked from points on an idealized flame to locations along the fuel bed while accounting for absorption by environmental water vapor in the intervening medium. The Spectral Line Weighted-sum-of-gray-gases approach was employed for treating the...

  6. Colorimetric Detection of Water Vapor Using Metal-Organic Framework Composites.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Purpose: Water vapor trapped in encapsulation materials or enclosed volumes leads to corrosion issues for critical NW components. Sandia National Laboratories has created a new diagnostic to indicate the presence of water in weapon systems. Impact: Component exposure to water now can be determined instantly, without need for costly, time-consuming analytical methods.

  7. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Science.gov (United States)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  8. Water Vapor on Titan: The Stratospheric Vertical Profile from Cassini/CIRS Infrared Spectra

    Science.gov (United States)

    Cottini, V.; Jennings, D. E.; Nixon, C. A.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Achterberg, R. K.; Teanby, N. A.; deKok, R.; hide

    2012-01-01

    Water vapor in Titan's middle atmosphere has previously been detected only by disk-average observations from the Infrared Space Observatory (Coustenis et al., 1998). We report here the successful detection of stratospheric water vapor using the Cassini Composite Infrared Spectrometer (CIRS, Flasar et al., 2004) following an earlier null result (de Kok et al., 2007a). CIRS senses water emissions in the far-infrared spectral region near 50 microns, which we have modeled using two independent radiative transfer and inversion codes (NEMESIS, Irwin et al 2008 and ART, Coustenis et al., 2010). From the analysis of nadir spectra we have derived a mixing ratio of (0.14 plus or minus 0.05) ppb at 100 km, corresponding to a column abundance of approximately (3.7 plus or minus 1.3) x 10(exp 14) moles per square centimeter. Using limb observations, we obtained mixing ratios of (0.13 plus or minus 0.04) ppb at 125 km and (0.45 plus or minus 0.15) ppb at 225 km of altitude, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. In the latitude range (80 deg. S - 30 deg. N) we see no evidence for latitudinal variations in these abundances within the error bars.

  9. Significant Features of Warm Season Water Vapor Flux Related to Heavy Rainfall and Draught in Japan

    Science.gov (United States)

    Nishiyama, Koji; Iseri, Yoshihiko; Jinno, Kenji

    2009-11-01

    In this study, our objective is to reveal complicated relationships between spatial water vapor inflow patterns and heavy rainfall activities in Kyushu located in the western part of Japan, using the outcomes of pattern recognition of water vapor inflow, based on the Self-Organizing Map. Consequently, it could be confirmed that water vapor inflow patterns control the distribution and the frequency of heavy rainfall depending on the direction of their fluxes and the intensity of Precipitable water. Historically serious flood disasters in South Kyushu in 1993 were characterized by high frequency of the water vapor inflow patterns linking to heavy rainfall. On the other hand, severe draught in 1994 was characterized by inactive frontal activity that do not related to heavy rainfall.

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

    Science.gov (United States)

    Tucker, George F.

    1994-01-01

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

  11. Measurements and modeling of absorption by CO2 + H2O mixtures in the spectral region beyond the CO2 ν3-band head

    Science.gov (United States)

    Tran, H.; Turbet, M.; Chelin, P.; Landsheere, X.

    2018-05-01

    In this work, we measured the absorption by CO2 + H2O mixtures from 2400 to 2600 cm-1 which corresponds to the spectral region beyond the ν3 band head of CO2. Transmission spectra of CO2 mixed with water vapor were recorded with a high-resolution Fourier-transform spectrometer for various pressure, temperature and concentration conditions. The continuum absorption by CO2 due to the presence of water vapor was determined by subtracting from measured spectra the contribution of local lines of both species, that of the continuum of pure CO2 as well as of the self- and CO2-continua of water vapor induced by the H2O-H2O and H2O-CO2 interactions. The obtained results are in very good agreement with the unique previous measurement (in a narrower spectral range). They confirm that the H2O-continuum of CO2 is significantly larger than that observed for pure CO2. This continuum thus must be taken into account in radiative transfer calculations for media involving CO2+ H2O mixture. An empirical model, using sub-Lorentzian line shapes based on some temperature-dependent correction factors χ is proposed which enables an accurate description of the experimental results.

  12. Compact Raman Lidar Measurement of Liquid and Vapor Phase Water Under the Influence of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Shiina Tatsuo

    2016-01-01

    Full Text Available A compact Raman lidar has been developed for studying phase changes of water in the atmosphere under the influence of ionization radiation. The Raman lidar is operated at the wavelength of 349 nm and backscattered Raman signals of liquid and vapor phase water are detected at 396 and 400 nm, respectively. Alpha particles emitted from 241Am of 9 MBq ionize air molecules in a scattering chamber, and the resulting ions lead to the formation of liquid water droplets. From the analysis of Raman signal intensities, it has been found that the increase in the liquid water Raman channel is approximately 3 times as much as the decrease in the vapor phase water Raman channel, which is consistent with the theoretical prediction based on the Raman cross-sections. In addition, the radius of the water droplet is estimated to be 0.2 μm.

  13. Water vapor as a perspective coolant for fast reactors

    International Nuclear Information System (INIS)

    Kalafati, D.D.; Petrov, S.I.

    1978-01-01

    Based on analysis of foreign projects of nuclear power plants with steam-cooled fast reactors, it is shown that low breeding ratio and large doubling time were caused by using nickel alloys, high vapor pressure and small volume heat release. The possibility is shown of obtaining doubling time in the necessary limits of T 2 =10-12 years when the above reasons for steam-cooled reactors are eliminated. Favourable combination of thermophysical and thermodynamic properties of water vapor makes it perspective coolant for power fast reactors

  14. Water vapor changes under global warming and the linkage to present-day interannual variabilities in CMIP5 models

    Science.gov (United States)

    Takahashi, Hanii; Su, Hui; Jiang, Jonathan H.

    2016-12-01

    The fractional water vapor changes under global warming across 14 Coupled Model Intercomparison Project Phase 5 simulations are analyzed. We show that the mean fractional water vapor changes under global warming in the tropical upper troposphere between 300 and 100 hPa range from 12.4 to 28.0 %/K across all models while the fractional water vapor changes are about 5-8 %/K in other regions and at lower altitudes. The "upper-tropospheric amplification" of the water vapor change is primarily driven by a larger temperature increase in the upper troposphere than in the lower troposphere per degree of surface warming. The relative contributions of atmospheric temperature and relative humidity changes to the water vapor change in each model vary between 71.5 to 131.8 % and 24.8 to -20.1 %, respectively. The inter-model differences in the water vapor change is primarily caused by differences in temperature change, except over the inter-tropical convergence zone within 10°S-10°N where the model differences due to the relative humidity change are significant. Furthermore, we find that there is generally a positive correlation between the rates of water vapor change for long-tem surface warming and those on the interannual time scales. However, the rates of water vapor change under long-term warming have a systematic offset from those on the inter-annual time scales and the dominant contributor to the differences also differs for the two time scales, suggesting caution needs to be taken when inferring long-term water vapor changes from the observed interannual variations.

  15. Raman scattering temperature measurements for water vapor in nonequilibrium dispersed two-phase flow

    International Nuclear Information System (INIS)

    Anastasia, C.M.; Neti, S.; Smith, W.R.; Chen, J.C.

    1982-09-01

    The objective of this investigation was to determine the feasibility of using Raman scattering as a nonintrusive technique to measure vapor temperatures in dispersed two-phase flow. The Raman system developed for this investigation is described, including alignment of optics and optimization of the photodetector for photon pulse counting. Experimentally obtained Raman spectra are presented for the following single- and two-phase samples: liquid water, atmospheric nitrogen, superheated steam, nitrogen and water droplets in a high void fraction air/water mist, and superheated water vapor in nonequilibrium dispersed flow

  16. Improved cell for water-vapor electrolysis

    Science.gov (United States)

    Aylward, J. R.

    1981-01-01

    Continuous-flow electrolytic cells decompose water vapor in steam and room air into hydrogen and oxygen. Sintered iridium oxide catalytic anode coating yields dissociation rates hundredfold greater than those obtained using platinum black. Cell consists of two mirror-image cells, with dual cathode sandwiched between two anodes. Gas traverses serpentine channels within cell and is dissociated at anode. Oxygen mingles with gas stream, while hydrogen migrates through porous matrix and is liberated as gas at cathode.

  17. Determination of the δ15N and δ18O of nitrate in water; RSIL lab code 2900

    Science.gov (United States)

    Coplen, Tyler B.; Qi, Haiping; Revesz, Kinga; Casciotti, Karen; Hannon, Janet E.

    2007-01-01

    The purpose of the Reston Stable Isotope Laboratory (RSIL) lab code 2900 is to determine the δ15N and δ18O of nitrate (NO3-) in water. The δ15N and δ18O of the dissolved NO3- are analyzed by converting the NO3- to nitrous oxide (N2O), which serves as the analyte for mass spectrometry. A culture of denitrifying bacteria is used in the enzymatic conversion of the NO3- to N2O, which follows the pathway shown in equation 1: NO3- → NO2- → NO → 1/2 N2O (1) Because the bacteria Pseudomonas aureofaciens lack N2O reductive activity, the reaction stops at N2O, unlike the typical denitrification reaction that goes to N2. After several hours, the conversion is complete, and the N2O is extracted from the vial, separated from volatile organic vapor and water vapor by an automated -65 °C isopropanol-slush trap, a Nafion drier, a CO2 and water removal unit (Costech #021020 carbon dioxide absorbent with Mg(ClO4)2), and trapped in a small-volume trap immersed in liquid nitrogen with a modified Finnigan MAT (now Thermo Scientific) GasBench 2 introduction system. After the N2O is released, it is further purified by gas chromatography before introduction to the isotope-ratio mass spectrometer (IRMS). The IRMS is a Thermo Scientific Delta V Plus continuous flow IRMS (CF-IRMS). It has a universal triple collector, consisting of two wide cups with a narrow cup in the middle; it is capable of simultaneously measuring mass/charge (m/z) of the N2O molecule 44, 45, and 46. The ion beams from these m/z values are as follows: m/z = 44 = N2O = 14N14N16O; m/z = 45 = N2O = 14N15N16O or 14N14N17O; m/z = 46 = N2O = 14N14N18O. The 17O contributions to the m/z 44 and m/z 45 ion beams are accounted for before δ15N values are reported.

  18. Pebax®1657/Graphene oxide composite membranes for improved water vapor separation

    KAUST Repository

    Akhtar, Faheem Hassan; Kumar, Mahendra; Peinemann, Klaus-Viktor

    2016-01-01

    In this study composite mixed matrix membranes containing hydrophilic microphase-separated block copolymer (Pebax® 1657) and graphene oxide nanosheets were prepared using a dip coating method. Water vapor and N2 gas permeation were measured as a function of different parameters: (i) layer thickness, (ii) content of graphene oxide (GO), and (iii) content of reduced GO. Surprisingly, a concentration of only 2 wt% of GO nanosheets well dispersed in the Pebax layer boosted the selectivity 8 times by decreasing the water vapor permeance by only 12% whereas N2 gas permeance decreased by 70%. Using reduced GO instead, the water vapor permeance declined by up to 16% with no influence on the N2 gas permeance. We correlated the permeation properties of the mixed matrix membranes with different models and found, that both the modified Nielsen model and the Cussler model give good correlation with experimental findings.

  19. Pebax®1657/Graphene oxide composite membranes for improved water vapor separation

    KAUST Repository

    Akhtar, Faheem Hassan

    2016-11-02

    In this study composite mixed matrix membranes containing hydrophilic microphase-separated block copolymer (Pebax® 1657) and graphene oxide nanosheets were prepared using a dip coating method. Water vapor and N2 gas permeation were measured as a function of different parameters: (i) layer thickness, (ii) content of graphene oxide (GO), and (iii) content of reduced GO. Surprisingly, a concentration of only 2 wt% of GO nanosheets well dispersed in the Pebax layer boosted the selectivity 8 times by decreasing the water vapor permeance by only 12% whereas N2 gas permeance decreased by 70%. Using reduced GO instead, the water vapor permeance declined by up to 16% with no influence on the N2 gas permeance. We correlated the permeation properties of the mixed matrix membranes with different models and found, that both the modified Nielsen model and the Cussler model give good correlation with experimental findings.

  20. Preprototype vapor compression distillation subsystem. [recovering potable water from wastewater

    Science.gov (United States)

    Ellis, G. S.; Wynveen, R. A.; Schubert, F. H.

    1979-01-01

    A three-person capacity preprototype vapor compression distillation subsystem for recovering potable water from wastewater aboard spacecraft was designed, assembled, and tested. The major components of the subsystem are: (1) a distillation unit which includes a compressor, centrifuge, central shaft, and outer shell; (2) a purge pump; (3) a liquids pump; (4) a post-treat cartridge; (5) a recycle/filter tank; (6) an evaporator high liquid level sensor; and (7) the product water conductivity monitor. A computer based control monitor instrumentation carries out operating mode change sequences, monitors and displays subsystem parameters, maintains intramode controls, and stores and displays fault detection information. The mechanical hardware occupies 0.467 m3, requires 171 W of electrical power, and has a dry weight of 143 kg. The subsystem recovers potable water at a rate of 1.59 kg/hr, which is equivalent to a duty cycle of approximately 30% for a crew of three. The product water has no foul taste or odor. Continued development of the subsystem is recommended for reclaiming water for human consumption as well as for flash evaporator heat rejection, urinal flushing, washing, and other on-board water requirements.

  1. Electric field effects in graphene/LaAlO3/SrTiO3 heterostructures and nanostructures

    Directory of Open Access Journals (Sweden)

    Mengchen Huang

    2015-06-01

    Full Text Available We report the development and characterization of graphene/LaAlO3/SrTiO3 heterostructures. Complex-oxide heterostructures are created by pulsed laser deposition and are integrated with graphene using both mechanical exfoliation and transfer from chemical-vapor deposition on ultraflat copper substrates. Nanoscale control of the metal-insulator transition at the LaAlO3/SrTiO3 interface, achieved using conductive atomic force microscope lithography, is demonstrated to be possible through the graphene layer. LaAlO3/SrTiO3-based electric field effects using a graphene top gate are also demonstrated. The ability to create functional field-effect devices provides the potential of graphene-complex-oxide heterostructures for scientific and technological advancement.

  2. CdS Nanoparticle-Modified α-Fe2O3/TiO2 Nanorod Array Photoanode for Efficient Photoelectrochemical Water Oxidation.

    Science.gov (United States)

    Yin, Ruiyang; Liu, Mingyang; Tang, Rui; Yin, Longwei

    2017-09-02

    In this work, we demonstrate a facile successive ionic layer adsorption and reaction process accompanied by hydrothermal method to synthesize CdS nanoparticle-modified α-Fe 2 O 3 /TiO 2 nanorod array for efficient photoelectrochemical (PEC) water oxidation. By integrating CdS/α-Fe 2 O 3 /TiO 2 ternary system, light absorption ability of the photoanode can be effectively improved with an obviously broadened optical-response to visible light region, greatly facilitates the separation of photogenerated carriers, giving rise to the enhancement of PEC water oxidation performance. Importantly, for the designed abnormal type-II heterostructure between Fe 2 O 3 /TiO 2 , the conduction band position of Fe 2 O 3 is higher than that of TiO 2 , the photogenerated electrons from Fe 2 O 3 will rapidly recombine with the photogenerated holes from TiO 2 , thus leads to an efficient separation of photogenerated electrons from Fe 2 O 3 /holes from TiO 2 at the Fe 2 O 3 /TiO 2 interface, greatly improving the separation efficiency of photogenerated holes within Fe 2 O 3 and enhances the photogenerated electron injection efficiency in TiO 2 . Working as the photoanodes of PEC water oxidation, CdS/α-Fe 2 O 3 /TiO 2 heterostucture electrode exhibits improved photocurrent density of 0.62 mA cm - 2 at 1.23 V vs. reversible hydrogen electrode (RHE) in alkaline electrolyte, with an obviously negatively shifted onset potential of 80 mV. This work provides promising methods to enhance the PEC water oxidation performance of the TiO 2 -based heterostructure photoanodes.

  3. Investigation of catalytic oxidation of diamond by water vapor and carbon dioxide in the presence of alkali melts of some rare earth oxides

    International Nuclear Information System (INIS)

    Kulakova, I.I.; Rudenko, A.P.; Sulejmenova, A.S.; Tolstopyatova, A.A.

    1978-01-01

    The results of an investigation of the catalytic oxydation of diamond by carbon dioxide and water vapors at 906 deg C in the presence of melts of some rare earth oxides in potassium hydroxide are given. The ion La 3+ was shown to possess the most catalytic activity. The earlier proposed mechanisms of the diamond oxidation by CO 2 and H 2 O were corroborated. The ions of rare earth elements were found to accelerate the different stages of the process

  4. Distribution of binding energies of a water molecule in the water liquid-vapor interface

    Energy Technology Data Exchange (ETDEWEB)

    Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV

    2008-01-01

    Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

  5. Partitioning the effects of Global Warming on the Hydrological Cycle with Stable Isotopes in Water Vapor

    Science.gov (United States)

    Dee, S. G.; Russell, J. M.; Nusbaumer, J. M.; Konecky, B. L.; Buenning, N. H.; Lee, J. E.; Noone, D.

    2016-12-01

    General circulation models (GCMs) suggest that much of the global hydrological cycle's response to anthropogenic warming will be caused by increased lower-tropospheric water vapor concentrations and associated feedbacks. However, fingerprinting changes in the global hydrological cycle due to anthropogenic warming remains challenging. Held and Soden (2006) predicted that as lower-tropospheric water vapor increases, atmospheric circulation will weaken as climate warms to maintain the surface energy budget. Unfortunately, the strength of this feedback and the fallout for other branches of the hydrological cycle is difficult to constrain in situ or with GCMs alone. We demonstrate the utility of stable hydrogen isotope ratios in atmospheric water vapor to quantitatively trace changes in atmospheric circulation and convective mass flux in a warming world. We compare water isotope-enabled GCM experiments for control (present-day) CO2 vs. high CO2(2x, 4x) atmospheres in two GCMs, IsoGSM and iCAM5. We evaluate changes in the distribution of water vapor, vertical velocity (omega), and the stream function between these experiments in order to identify spatial patterns of circulation change over the tropical Pacific (where vertical motion is strong) and map the δD of water vapor associated with atmospheric warming. We also probe the simulations to isolate isotopic signatures associated with water vapor residence time, precipitation efficiency, divergence, and cloud physics. We show that there are robust mechanisms that moisten the troposphere and weaken convective mass flux, and that these mechanisms can be tracked using the δD of water vapor. Further, we find that these responses are most pronounced in the upper troposphere. These findings provide a framework to develop new metrics for the detection of global warming impacts to the hydrological cycle. Further, currently available satellite missions measure δD in the atmospheric boundary layer, the free atmosphere, or the

  6. P-channel transparent thin-film transistor using physical-vapor-deposited NiO layer

    Science.gov (United States)

    Lin, Chiung-Wei; Chung, Wei-Chieh; Zhang, Zhao-De; Hsu, Ming-Chih

    2018-01-01

    The effect of oxygen (O) content on the electrical properties of physical-vapor-deposited nickel oxide (PVD-NiO) was studied. When the NiO target was sputtered, introducing O2 can lead to the formation of Ni3+ ions in the deposited film. These Ni3+ ions can act as acceptors. However, there were too many Ni3+ ions that were obtained following the introduction of O atoms. It resulted in intensive p-type conduction and made the O2-introduced PVD-NiO behave as a conductor. Thus, it was possible to reduce the O content of PVD-NiO to obtain a p-type semiconductor. In this study, a transparent PVD-NiO film with a carrier concentration of 1.62 × 1017 cm-3 and a resistivity of 3.74 Ω cm was sputter-deposited within pure argon plasma. The thin-film transistor (TFT) employing this proposed PVD-NiO can result in good current switching, and even operated at very low drain-source voltage. The ON/OFF current ratio, field-effect carrier mobility, and threshold voltage of the proposed NiO TFT were 3.61 × 104, 1.09 cm2 V-1 s-1 and -3.31 V, respectively.

  7. Computer simulation of the NASA water vapor electrolysis reactor

    Science.gov (United States)

    Bloom, A. M.

    1974-01-01

    The water vapor electrolysis (WVE) reactor is a spacecraft waste reclamation system for extended-mission manned spacecraft. The WVE reactor's raw material is water, its product oxygen. A computer simulation of the WVE operational processes provided the data required for an optimal design of the WVE unit. The simulation process was implemented with the aid of a FORTRAN IV routine.

  8. Raman scattering studies of YBa2Cu3O7-x thin films grown by chemical vapor deposition and metal-organic deposition

    International Nuclear Information System (INIS)

    Lee, E.; Yoon, S.; Um, Y.M.; Jo, W.; Seo, C.W.; Cheong, H.; Kim, B.J.; Lee, H.G.; Hong, G.W.

    2007-01-01

    We present results of Raman scattering studies of superconducting YBa 2 Cu 3 O 7-x (YBCO) films grown by chemical vapor deposition and metal-organic deposition methods. It is shown by X-ray diffraction that all the as-grown YBCO films have a highly c-axis oriented and in-plane aligned texture. Raman scattering measurements were used to investigate optical phonon modes, oxygen contents, structural properties, and second-phases of the YBCO coated conductors. Raman spectra of YBCO films with lower-transport qualities exhibit additional phonon modes at ∼300 cm -1 , ∼600 cm -1 , and ∼630 cm -1 , which are related to second-phases such as Ba 2 Cu 3 O 5.9 and BaCuO 2 . Our results strongly suggest that Raman scattering be useful for optimizing YBCO film growth conditions

  9. Water vapor measurements at ALOMAR over a solar cycle compared with model calculations by LIMA

    Science.gov (United States)

    Hartogh, P.; Sonnemann, G. R.; Grygalashvyly, M.; Song, Li; Berger, U.; Lübken, F.-J.

    2010-01-01

    Microwave water vapor measurements between 40 and 80 km altitude over a solar cycle (1996-2006) were carried out in high latitudes at Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) (69.29°N, 16.03°E), Norway. Some smaller gaps and three interruptions of monitoring in the winters 1996/1997 and 2005/2006 and from spring 2001 to spring 2002 occurred during this period. The observations show a distinct year-to-year variability not directly related to solar Lyman-α radiation. In winter the water vapor mixing ratios in the upper domain were anticorrelated to the solar activity, whereas in summer, minima occurred in the years after the solar maximum in 2000/2001. In winter, sudden stratospheric warmings (SSWs) modulated the water vapor mixing ratios. Within the stratopause region a middle atmospheric water vapor maximum was observed, which results from the methane oxidation and is a regular feature there. The altitude of the maximum increased by approximately 5 km as summer approached. The largest mixing ratios were monitored in autumn. During the summer season a secondary water vapor maximum also occurred above 65 km most pronounced in late summer. The solar Lyman-α radiation impacts the water vapor mixing ratio particularly in winter above 65 km. In summer the correlation is positive below 70 km. The correlation is also positive in the lower mesosphere/stratopause region in winter due to the action of sudden stratospheric warmings, which occur more frequently under the condition of high solar activity and the enhancing the humidity. A strong day-to-day variability connected with planetary wave activity was found throughout the entire year. Model calculations by means of Leibniz-Institute Middle Atmosphere model (LIMA) reflect the essential patterns of the water vapor variation, but the results also show differences from the observations, indicating that exchange processes between the troposphere and stratosphere not modeled by LIMA could have

  10. Vacuum distillation/vapor filtration water recovery, phases 1 and 2

    Science.gov (United States)

    Honegger, R. J.; Remus, G. A.; Krug, E. K.

    1973-01-01

    The research is reported on the development of an evaporator for vacuum distillation/vapor filtration VD/VF water reclamation system for use on manned space flights. The design, fabrication, and tests of a six-man evaporator are described. It is concluded that: (1) A condenser with an internal rotating impeller and coolant surfaces directly opposite the condensing surfaces is an effective condenser. (2) The VD/VF evaporator, catalyst unit and condenser function satisfactorily based on thermal, mechanical and recovery performance during a 145-hour evaluation test. (3) The quality of recovered water, as measured by analyses for total organic carbon, pH, conductivity, turbidity, and viable bacteria density was within established limits for potability.

  11. Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle

    KAUST Repository

    Kim, Youngdeuk

    2014-07-01

    The adsorption characteristics of microporous ferroaluminophosphate adsorbent (FAM-Z01, Mitsubishi Plastics) are evaluated for possible application in adsorption desalination and cooling (AD) cycles. A particular interest is its water vapor uptake behavior at assorted adsorption temperatures and pressures whilst comparing them to the commercial silica gels of AD plants. The surface characteristics are first carried out using N2 gas adsorption followed by the water vapor uptake analysis for temperature ranging from 20°C to 80°C. We propose a hybrid isotherm model, composing of the Henry and the Sips isotherms, which can be integrated to satisfactorily fit the experimental data of water adsorption on the FAM-Z01. The hybrid model is selected to fit the unusual isotherm shapes, that is, a low adsorption in the initial section and followed by a rapid vapor uptake leading to a likely micropore volume filling by hydrogen bonding and cooperative interaction in micropores. It is shown that the equilibrium adsorption capacity of FAM-Z01 can be up to 5 folds higher than that of conventional silica gels. Owing to the quantum increase in the adsorbate uptake, the FAM-Z01 has the potential to significantly reduce the footprint of an existing AD plant for the same output capacity. © 2014 Elsevier B.V.

  12. ZnO/SnO{sub 2} nanoflower based ZnO template synthesized by thermal chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sin, N. D. Md., E-mail: diyana0366@johor.uitm.edu.my; Amalina, M. N., E-mail: amalina0942@johor.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Fakulti Kejuruteraan Elektrik, Universiti Teknologi MARA Cawangan Johor, Kampus Pasir Gudang, 81750 Masai, Johor (Malaysia); Ismail, Ahmad Syakirin, E-mail: kyrin-samaxi@yahoo.com; Shafura, A. K., E-mail: shafura@ymail.com; Ahmad, Samsiah, E-mail: samsiah.ahmad@johor.uitm.edu.my; Mamat, M. H., E-mail: mhmamat@salam.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); Rusop, M., E-mail: rusop@salam.uitm.edu.my [NANO-ElecTronic Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia)

    2016-07-06

    The ZnO/SnO{sub 2} nanoflower like structures was grown on a glass substrate deposited with seed layer using thermal chemical vapor deposition (CVD) with combining two source materials. The ZnO/SnO{sub 2} nanoflower like structures had diameter in the range 70 to 100 nm. The atomic percentage of ZnO nanoparticle , SnO{sub 2} nanorods and ZnO/SnO{sub 2} nanoflower was taken using EDS. Based on the FESEM observations, the growth mechanism is applied to describe the growth for the synthesized nanostructures.

  13. Classification of cassava starch films by physicochemical properties and water vapor permeability quantification by FTIR and PLS.

    Science.gov (United States)

    Henrique, C M; Teófilo, R F; Sabino, L; Ferreira, M M C; Cereda, M P

    2007-05-01

    Cassava starches are widely used in the production of biodegradable films, but their resistance to humidity migration is very low. In this work, commercial cassava starch films were studied and classified according to their physicochemical properties. A nondestructive method for water vapor permeability determination, which combines with infrared spectroscopy and multivariate calibration, is also presented. The following commercial cassava starches were studied: pregelatinized (amidomax 3550), carboxymethylated starch (CMA) of low and high viscosities, and esterified starches. To make the films, 2 different starch concentrations were evaluated, consisting of water suspensions with 3% and 5% starch. The filmogenic solutions were dried and characterized for their thickness, grammage, water vapor permeability, water activity, tensile strength (deformation force), water solubility, and puncture strength (deformation). The minimum thicknesses were 0.5 to 0.6 mm in pregelatinized starch films. The results were treated by means of the following chemometric methods: principal component analysis (PCA) and partial least squares (PLS) regression. PCA analysis on the physicochemical properties of the films showed that the differences in concentration of the dried material (3% and 5% starch) and also in the type of starch modification were mainly related to the following properties: permeability, solubility, and thickness. IR spectra collected in the region of 4000 to 600 cm(-1) were used to build a PLS model with good predictive power for water vapor permeability determination, with mean relative errors of 10.0% for cross-validation and 7.8% for the prediction set.

  14. The Effect of Water Vapor on the Thermal Decomposition of Pyrite in N2 Atmosphere

    Directory of Open Access Journals (Sweden)

    Nesrin BOYABAT

    2009-03-01

    Full Text Available In this study, the effect of water vapor on the thermal decomposition of pyrite mineral in nitrogen atmosphere has been investigated in a horizontal tube furnace. Temperature, time and water vapor concentration were used as experimental parameters. According to the data obtained at nitrogen/ water vapor environment, it was observed that the water vapor on the decomposition of pyrite increased the decomposition rate. The decomposition reaction is well represented by the "shrinking core" model and can be divided into two regions with different rate controlling step. The rate controlling steps were determined from the heat transfer through the gas film for the low conversions, while it was determined from the mass transfer through product ash layer for the high conversions. The activation energies of this gas and ash film mechanisms were found to be 77 and 81 kJ/mol-1, respectively.

  15. DETERMINING HOW VAPOR PHASE MTBE REACHES GROUND WATER

    Science.gov (United States)

    EPA Region 2 and ORD have funded a RARE project for FY 2005/2006 to evaluate the prospects that MTBE (and other fuel components) in vapors that escape from an underground storage tank (UST) can find its way to ground water produced by monitoring wells at a gasoline filling statio...

  16. Water vapor increase in the northern hemispheric lower stratosphere by the Asian monsoon anticyclone observed during TACTS campaign in 2012

    Science.gov (United States)

    Rolf, Christian; Vogel, Bärbel; Hoor, Peter; Günther, Gebhard; Krämer, Martina; Müller, Rolf; Müller, Stephan; Riese, Martin

    2017-04-01

    Water vapor plays a key role in determining the radiative balance in the upper troposphere and lower stratosphere (UTLS) and thus the climate of the Earth (Forster and Shine, 2002; Riese et al., 2012). Therefore a detailed knowledge about transport pathways and exchange processes between troposphere and stratosphere is required to understand the variability of water vapor in this region. The Asian monsoon anticyclone caused by deep convection over and India and east Asia is able to transport air masses from the troposphere into the nothern extra-tropical stratosphere (Müller et al. 2016, Vogel et al. 2016). These air masses contain pollution but also higher amounts of water vapor. An increase in water vapor of about 0.5 ppmv in the extra-tropical stratosphere above a potential temperature of 380 K was detected between August and September 2012 by in-situ instrumentation above the European northern hemisphere during the HALO aircraft mission TACTS. Here, we investigated the origin of this water vapor increase with the help of the 3D Lagrangian chemistry transport model CLaMS (McKenna et al., 2002). We can assign an origin of the moist air masses in the Asian region (North and South India and East China) with the help of model origin tracers. Additionally, back trajectories of these air masses with enriched water vapor are used to differentiate between transport from the Asia monsoon anticyclone and the upwelling of moister air in the tropics particularly from the Pacific and Southeast Asia.

  17. The Observed Relationship Between Water Vapor and Ozone in the Tropical Tropopause Saturation Layer and the Influence of Meridional Transport

    Science.gov (United States)

    Selkirk, Henry B.; Schoeberl, M. R.; Olsen, M. A.; Douglass, A. R.

    2011-01-01

    We examine balloonsonde observations of water vapor and ozone from three Ticosonde campaigns over San Jose, Costa Rica [10 N, 84 W] during northern summer and a fourth during northern winter. The data from the summer campaigns show that the uppermost portion of the tropical tropopause layer between 360 and 380 K, which we term the tropopause saturation layer or TSL, is characterized by water vapor mixing ratios from proximately 3 to 15 ppmv and ozone from approximately 50 ppbv to 250 ppbv. In contrast, the atmospheric water vapor tape recorder at 380 K and above displays a more restricted 4-7 ppmv range in water vapor mixing ratio. From this perspective, most of the parcels in the TSL fall into two classes - those that need only additional radiative heating to rise into the tape recorder and those requiring some combination of additional dehydration and mixing with drier air. A substantial fraction of the latter class have ozone mixing ratios greater than 150 ppbv, and with water vapor greater than 7 ppmv this air may well have been transported into the tropics from the middle latitudes in conjunction with high-amplitude equatorial waves. We examine this possibility with both trajectory analysis and transport diagnostics based on HIRDLS ozone data. We apply the same approach to study the winter season. Here a very different regime obtains as the ozone-water vapor scatter diagram of the sonde data shows the stratosphere and troposphere to be clearly demarcated with little evidence of mixing in of middle latitude air parcels.

  18. Nanotextured Spikes of α-Fe2O3/NiFe2O4 Composite for Efficient Photoelectrochemical Oxidation of Water.

    Science.gov (United States)

    Hussain, Shabeeb; Tavakoli, Mohammad Mahdi; Waleed, Aashir; Virk, Umar Siddique; Yang, Shihe; Waseem, Amir; Fan, Zhiyong; Nadeem, Muhammad Arif

    2018-03-27

    We demonstrate for the first time the application of p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe 2 O 4 and Fe 2 O 3 ) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe 2 O 4 /n-Fe 2 O 3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured p-NiFe 2 O 4 /n-Fe 2 O 3 device with equal molar 1:1 ratio of NiFe 2 O 4 and Fe 2 O 3 was found to be highly efficient for PEC water oxidation as compared with pure hematite, 1:2 and 1:3 molar ratios of composite. The photocurrent density of 1:1 composite thin film on planar substrate was equal to 1.07 mA/cm 2 at 1.23 V RHE , which was 1.7 times higher current density as compared with pure hematite device (0.63 mA/cm 2 at 1.23 V RHE ). The performance of p-NiFe 2 O 4 /n-Fe 2 O 3 composites in PEC water oxidation was further enhanced by their deposition over 3D-NSP substrate. The highest photocurrent density of 2.1 mA/cm 2 at 1.23 V RHE was obtained for the 1:1 molar ratio p-NiFe 2 O 4 /n-Fe 2 O 3 composite on NSP (NF1-NSP), which was 3.3 times more photocurrent density than pure hematite. The measured applied bias photon-to-current efficiency (ABPE) value of NF1-NSP (0.206%) was found to be 1.87 times higher than that of NF1-P (0.11%) and 4.7 times higher than that of pure hematite deposited on FTO-coated glass (0.044%). The higher PEC water oxidation activity of p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin film as compared with pure hematite is attributed to the Z-path scheme and better separation of electrons and holes. The increased surface area and greater light

  19. Vapor-liquid equilibria for the acetone-ethanol-n-propanol-tert-butanol-water system

    Energy Technology Data Exchange (ETDEWEB)

    Tochigi, K.; Uchida, K.; Kojima, K.

    1981-12-01

    This study deals with the measurement of vapor-liquid equilibria for the five-component system acetone-ethanol-n-propanol-tert-butanol-water at 760 mmHg and prediction of vapor-liquid equilibria by the ASOG group contribution method. The five-component system in this work is composed of a part of the components obtained during ethanol production by vapor-phase hydration of ethylene. 6 refs.

  20. The compositional, structural, and magnetic properties of a Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN spin injecting hetero-structure grown by metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhonghua; Huang, Shimin [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Tang, Kun, E-mail: ktang@nju.edu.cn [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Gu, Shulin, E-mail: slgu@nju.edu.cn [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Zhu, Shunming [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Ye, Jiandong [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China); Nanjing University Institute of Optoelectronics at Yangzhou, Yangzhou 225009 (China); Xu, Mingxiang [Department of Physics, Southeast University, Nanjing 210096 (China); Wang, Wei; Zheng, Youdou [Nanjing National Laboratory of Microstructures and School of Electronic Science and Engineering, Nanjing University, Nanjing 210023 (China)

    2016-12-01

    Highlights: • The Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN hetero-structure has been fabricated by MOCVD successfully. • The formation mechanism of different layers in sample was revealed in details. • The properties of the hetero-structure have been presented and discussed extensively. • The effect of Ga diffusion on the magnetic properties of Fe{sub 3}O{sub 4} film has been shown. - Abstract: In this article, the authors have designed and fabricated a Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN spin injecting hetero-structure by metal-organic chemical vapor deposition. The compositional, structural, and magnetic properties of the hetero-structure have been characterized and discussed. From the characterizations, the hetero-structure has been successfully grown generally. However, due to the unintentional diffusion of Ga ions from Ga{sub 2}O{sub 3}/GaN layers, the most part of the nominal Fe{sub 3}O{sub 4} layer is actually in the form of Ga{sub x}Fe{sub 3−x}O{sub 4} with gradually decreased x values from the Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3} interface to the Fe{sub 3}O{sub 4} surface. Post-annealing process can further aggravate the diffusion. Due to the similar ionic radius of Ga and Fe, the structural configuration of the Ga{sub x}Fe{sub 3−x}O{sub 4} does not differ from that of pure Fe{sub 3}O{sub 4}. However, the ferromagnetism has been reduced with the incorporation of Ga into Fe{sub 3}O{sub 4}, which has been explained by the increased Yafet-Kittel angles in presence of considerable amount of Ga incorporation. A different behavior of the magnetoresistance has been found on the as-grown and annealed samples, which could be modelled and explained by the competition between the spin-dependent and spin-independent conduction channels. This work has provided detailed information on the interfacial properties of the Fe{sub 3}O{sub 4}/Ga{sub 2}O{sub 3}/GaN spin injecting hetero-structure, which is the solid basis for further improvement and application of

  1. Applying the Water Vapor Radiometer to Verify the Precipitable Water Vapor Measured by GPS

    Directory of Open Access Journals (Sweden)

    Ta-Kang Yeh

    2014-01-01

    Full Text Available Taiwan is located at the land-sea interface in a subtropical region. Because the climate is warm and moist year round, there is a large and highly variable amount of water vapor in the atmosphere. In this study, we calculated the Zenith Wet Delay (ZWD of the troposphere using the ground-based Global Positioning System (GPS. The ZWD measured by two Water Vapor Radiometers (WVRs was then used to verify the ZWD that had been calculated using GPS. We also analyzed the correlation between the ZWD and the precipitation data of these two types of station. Moreover, we used the observational data from 14 GPS and rainfall stations to evaluate three cases. The offset between the GPS-ZWD and the WVR-ZWD ranged from 1.31 to 2.57 cm. The correlation coefficient ranged from 0.89 to 0.93. The results calculated from GPS and those measured using the WVR were very similar. Moreover, when there was no rain, light rain, moderate rain, or heavy rain, the flatland station ZWD was 0.31, 0.36, 0.38, or 0.40 m, respectively. The mountain station ZWD exhibited the same trend. Therefore, these results have demonstrated that the potential and strength of precipitation in a region can be estimated according to its ZWD values. Now that the precision of GPS-ZWD has been confirmed, this method can eventually be expanded to the more than 400 GPS stations in Taiwan and its surrounding islands. The near real-time ZWD data with improved spatial and temporal resolution can be provided to the city and countryside weather-forecasting system that is currently under development. Such an exchange would fundamentally improve the resources used to generate weather forecasts.

  2. Atomic layer deposition of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}/TiO{sub 2} barrier coatings to reduce the water vapour permeability of polyetheretherketone

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadzada, Tamkin, E-mail: tahm4852@uni.sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); McKenzie, David R.; James, Natalie L.; Yin, Yongbai [School of Physics, University of Sydney, NSW 2006 (Australia); Li, Qing [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia)

    2015-09-30

    We demonstrate significantly enhanced barrier properties of polyetheretherketone (PEEK) against water vapour penetration by depositing Al{sub 2}O{sub 3} or Al{sub 2}O{sub 3}/TiO{sub 2} nanofilms grown by atomic layer deposition (ALD). Nanoindentation analysis revealed good adhesion strength of a bilayer Al{sub 2}O{sub 3}/TiO{sub 2} coating to PEEK, while the single layer Al{sub 2}O{sub 3} coating displayed flaking and delamination. We identified three critical design parameters for achieving the optimum barrier properties of ALD Al{sub 2}O{sub 3}/TiO{sub 2} coatings on PEEK. These are a minimum total thickness dependent on the required water vapour transmission rate, the use of an Al{sub 2}O{sub 3}/TiO{sub 2} bilayer coating and the application of the coating to both sides of the PEEK film. Using these design parameters, we achieved a reduction in moisture permeability of PEEK of over two orders of magnitude while maintaining good adhesion strength of the polymer–thin film system. - Highlights: • Atomic layer deposition of Al{sub 2}O{sub 3}/TiO{sub 2} coatings reduced water vapour permeability. • Bilayer coatings reduced the permeability more than single layer coatings. • Bilayer coatings displayed higher adhesion strength than the single layer coatings. • Double-sided coatings performed better than single-sided coatings. • Correlation was found between total thickness and reduced water vapour permeability.

  3. Small-scale experimental study of vaporization flux of liquid nitrogen released on water.

    Science.gov (United States)

    Gopalaswami, Nirupama; Olewski, Tomasz; Véchot, Luc N; Mannan, M Sam

    2015-10-30

    A small-scale experimental study was conducted using liquid nitrogen to investigate the convective heat transfer behavior of cryogenic liquids released on water. The experiment was performed by spilling five different amounts of liquid nitrogen at different release rates and initial water temperatures. The vaporization mass fluxes of liquid nitrogen were determined directly from the mass loss measured during the experiment. A variation of initial vaporization fluxes and a subsequent shift in heat transfer mechanism were observed with changes in initial water temperature. The initial vaporization fluxes were directly dependent on the liquid nitrogen spill rate. The heat flux from water to liquid nitrogen determined from experimental data was validated with two theoretical correlations for convective boiling. It was also observed from validation with correlations that liquid nitrogen was found to be predominantly in the film boiling regime. The substantial results provide a suitable procedure for predicting the heat flux from water to cryogenic liquids that is required for source term modeling. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Zero photoelastic and water durable ZnO-SnO-P2O5-B2O3 glasses

    Science.gov (United States)

    Saitoh, Akira; Nakata, Kohei; Tricot, Grégory; Chen, Yuanyuan; Yamamoto, Naoki; Takebe, Hiromichi

    2015-04-01

    We report properties of zero birefringent xZnO-(67-x)SnO-(33-y)P2O5-y B2O3 glasses, within 18.5 ≤ x ≤ 22 and y = 0, 3, and 10 mol. %. These compositions of boro-phosphate glasses provide both zero photoelastic constant (PEC) and improved water durability. x = 19 and y = 3 compositions show minimum PEC of -0.002 × 10-12 Pa-1, which can contribute to candidate material for fiber current sensor devise without lead. The structures of zero photoelastic glasses were investigated by Raman scattering and nuclear magnetic resonance spectroscopies. Compositions of zero PEC glasses are explained by the empirical model proposed by Zwanziger et al. [Chem. Mater. 19, 286-290 (2007)].

  5. 557 GHz Observations of Water Vapor Outflow from VY Canis Majoris and W Hydrae

    Science.gov (United States)

    Harwit, Martin; Bergin, Edwin A.

    2002-02-01

    We report the first detection of thermal water vapor emission in the 557 GHz, 110-101 ground-state transition of ortho-H2O toward VY Canis Majoris. In observations obtained with the Submillimeter Wave Astronomy Satellite, we measured a flux of ~450 Jy, in a spectrally resolved line centered on a velocity vLSR=25 km s-1 with an FWHM of ~35 km s-1, somewhat dependent on the assumed line shape. We analyze the line shape in the context of three different radial outflow models for which we provide analytical expressions. We also detected a weaker 557 GHz emission line from W Hydrae. We find that these and other H2O emission-line strengths scale as suggested by Zubko and Elitzur.

  6. Generation of real-time mode high-resolution water vapor fields from GPS observations

    Science.gov (United States)

    Yu, Chen; Penna, Nigel T.; Li, Zhenhong

    2017-02-01

    Pointwise GPS measurements of tropospheric zenith total delay can be interpolated to provide high-resolution water vapor maps which may be used for correcting synthetic aperture radar images, for numeral weather prediction, and for correcting Network Real-time Kinematic GPS observations. Several previous studies have addressed the importance of the elevation dependency of water vapor, but it is often a challenge to separate elevation-dependent tropospheric delays from turbulent components. In this paper, we present an iterative tropospheric decomposition interpolation model that decouples the elevation and turbulent tropospheric delay components. For a 150 km × 150 km California study region, we estimate real-time mode zenith total delays at 41 GPS stations over 1 year by using the precise point positioning technique and demonstrate that the decoupled interpolation model generates improved high-resolution tropospheric delay maps compared with previous tropospheric turbulence- and elevation-dependent models. Cross validation of the GPS zenith total delays yields an RMS error of 4.6 mm with the decoupled interpolation model, compared with 8.4 mm with the previous model. On converting the GPS zenith wet delays to precipitable water vapor and interpolating to 1 km grid cells across the region, validations with the Moderate Resolution Imaging Spectroradiometer near-IR water vapor product show 1.7 mm RMS differences by using the decoupled model, compared with 2.0 mm for the previous interpolation model. Such results are obtained without differencing the tropospheric delays or water vapor estimates in time or space, while the errors are similar over flat and mountainous terrains, as well as for both inland and coastal areas.

  7. Mass spectrometric study of vaporization of cesium tellurate and tellurite

    International Nuclear Information System (INIS)

    Semenov, G.A.; Fokina, L.A.; Mouldagalieva, R.A.

    1994-01-01

    The process of vaporization of cesium tellurate and tellurite was studied by the Knudsen effusion method with a mass spectrometric analysis of the vapor composition. The thermal dissociation of Cs 2 TeO 4 to Cs 2 TeO 3 and the congruent vaporization of Cs 2 TeO 3 were established. Thermodynamic functions for gaseous Cs 2 TeO 3 have been calculated. The standard enthalpy of sublimation Δ s H (298.15)=268.1±13.0 kJ mol -1 was determined by the 2nd and 3rd laws of thermodynamics. The enthalpy of formation Δ f H (298.15)=-725.1±13.0 kJ mol -1 for gaseous Cs 2 TeO 3 and the enthalpy of atomization Δ at H (298.15)=1841.3±15.0 kJ mol -1 have been computed. ((orig.))

  8. Evolution of the Water Vapor Plume over Eastern Europe during Summer 2010 Atmospheric Blocking

    Directory of Open Access Journals (Sweden)

    Sergei A. Sitnov

    2014-01-01

    Full Text Available We present an analysis of water vapor (WV plume evolution over Eastern Europe (EE during atmospheric blocking in the summer of 2010, carried out on the basis of satellite (MODIS and MLS instruments, aerological, and NCEP/NCAR reanalysis data. The obtained results show that the development of blocking was accompanied by the development of a positive anomaly of total column water vapor (TCWV content over the northern part of EE. Local TCWV content from 28 July to 6 August 2010 reached 3.35 cm, a value that exceeded by 3.3 times its content before the block. The surplus of WV was mainly conditioned by the advection of WV due to transfer of moist air from the Atlantic Ocean and the Mediterranean Sea into northern EE and also due to increased evaporation from the surface enriched with water due to increased temperature and wind. We hypothesize that the influx of latent heat in the block area can contribute to the energy supply of the blocking anticyclone and prolong the existence of block. Strong humidification of the troposphere and some dehumidification of the lower stratosphere during the block were accompanied by warming of the troposphere and cooling of the lower stratosphere.

  9. Chemically vapor deposited coatings for multibarrier containment of nuclear wastes

    International Nuclear Information System (INIS)

    Rusin, J.M.; Shade, J.W.; Kidd, R.W.; Browning, M.F.

    1981-01-01

    Chemical vapor deposition (CVD) was selected as a feasible method to coat ceramic cores, since the technology has previously been demonstrated for high-temperature gas-cooled reactor (HTGR) fuel particles. CVD coatings, including SiC, PyC (pyrolytic carbon), SiO 2 , and Al 2 O 3 were studied. This paper will discuss the development and characterization of PyC and Al 2 O 3 CVD coatings on supercalcine cores. Coatings were applied to 2 mm particles in either fluidized or vibrating beds. The PyC coating was deposited in a fluidized bed with ZrO 2 diluent from C 2 H 2 at temperatures between 1100 and 1200 0 C. The Al 2 O 3 coatings were deposited in a vibrated bed by a two-stage process to minimize loss of PyC during the overcoating operation. This process involved applying 10 μm of Al 2 O 3 using water vapor hydrolysis of AlCl 3 and then switching to the more surface-controlled hydrolysis via the H 2 + CO 2 reaction (3CO 2 + 3H 2 + 2AlCl 3 = Al 2 O 3 + 6HCl + 3CO). Typically, 50 to 80 μm Al 2 O 3 coatings were applied over 30 to 40 μm PyC coatings. The coatings were evaluated by metallographic examination, PyC oxidation tests, and leach resistance. After air oxidation for 100 hours at 750 0 C, the duplex PyC/Al 2 O 3 coated particles exhibited a weight loss of 0.01 percent. Leach resistance is being determined for temperatures from 50 to 150 0 C in various solutions. Typical results are given for selected ions. The leach resistance of supercalcine cores is significantly improved by the application of PyC and/or Al 2 O 3 coatings

  10. Role of Water Vapor Content in the Effects of Aerosol on the Electrification of Thunderstorms: A Numerical Study

    Directory of Open Access Journals (Sweden)

    Pengguo Zhao

    2016-10-01

    Full Text Available We explored the role of the water vapor content below the freezing level in the response of idealized supercell storm electrical processes to increased concentrations of cloud condensation nuclei (CCN. Using the Weather Research and Forecasting model coupled with parameterizations electrification and discharging, we performed 30 simulations by varying both the CCN concentration and water vapor content below the freezing level. The sensitivity simulations showed a distinct response to increased concentrations of CCN, depending on the water vapor content below the freezing level. Enhancing CCN concentrations increased electrification processes of thunderstorms and produced a new negative charge region above the main positive charge center when there were ample amounts of water vapor below the freezing level. Conversely, there were weak effects on electrification and the charge structure in numerical experiments initialized with lower water vapor content below the freezing level.

  11. GPS Water Vapor Tomography: First results from the ESCOMPTE Field Experiment

    Science.gov (United States)

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

    2003-04-01

    We develop a tomographic software to model the spatial distribution of the tropospheric water vapor from GPS data. First we present simulations based on a real GPS station distribution and simple tropospheric models, which prove the potentiality of the method. Second we apply the software to the ESCOMPTE data. During the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers has been operated for two weeks within a 20 km x 20 km area around Marseille (Southern France). The network extends from the sea level to the top of the Etoile chain (~700 m high). The input data are the slant delay values obtained by combining the estimated zenith delay values with the horizontal gradients. The effect of the initial tropospheric water vapor model, the number and thickness of the layers of the model, the a priori model and data covariance and some other parameters will be discussed. Simultaneously water vapor radiometer, solar spectrometer, Raman lidar and radiosondes have been deployed to get a data set usable for comparison with the tomographic inversion results and validation of the method. Comparison with meteorological models (MesoNH - Meteo-France) will be shown.

  12. Measurements of upper atmosphere water vapor made in situ with a new moisture sensor

    Science.gov (United States)

    Chleck, D.

    1979-01-01

    A new thin-film aluminum oxide sensor, Aquamax II, has been developed for the measurement of stratospheric and upper tropospheric water vapor levels. The sensor is briefly described with attention given to its calibration and performance. Data obtained from six balloon flights are presented; almost all the results show a constant water vapor mixing ratio, in agreement with other data from midlatitude regions.

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

    Science.gov (United States)

    Grant, William B.

    1991-01-01

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

  14. Optoacoustic measurements of water vapor absorption at selected CO laser wavelengths in the 5-micron region

    Science.gov (United States)

    Menzies, R. T.; Shumate, M. S.

    1976-01-01

    Measurements of water vapor absorption were taken with a resonant optoacoustical detector (cylindrical pyrex detector, two BaF2 windows fitted into end plates at slight tilt to suppress Fabry-Perot resonances), for lack of confidence in existing spectral tabular data for the 5-7 micron region, as line shapes in the wing regions of water vapor lines are difficult to characterize. The measurements are required for air pollution studies using a CO laser, to find the differential absorption at the wavelengths in question due to atmospheric constituents other than water vapor. The design and performance of the optoacoustical detector are presented. Effects of absorption by ambient NO are considered, and the fixed-frequency discretely tunable CO laser is found suitable for monitoring urban NO concentrations in a fairly dry climate, using the water vapor absorption data obtained in the study.

  15. Adsorption characteristics of water vapor on ferroaluminophosphate for desalination cycle

    KAUST Repository

    Kim, Youngdeuk; Thu, Kyaw; Ng, Kim Choon

    2014-01-01

    The adsorption characteristics of microporous ferroaluminophosphate adsorbent (FAM-Z01, Mitsubishi Plastics) are evaluated for possible application in adsorption desalination and cooling (AD) cycles. A particular interest is its water vapor uptake

  16. Plasticized Starch Based Bionanocomposites Containing Cellulose Nanowhiskers and Titanium Dioxide Nanoparticles: Study of Structure and Water Vapor Permeability

    Directory of Open Access Journals (Sweden)

    Nasrin Jamshidi Kaljahi

    2014-08-01

    Full Text Available The starch-based films have some disadvantages such as weak mechanical and poor water barrier properties that restrict their applications in food packaging. In the present research, to improve the properties of the starch films, a constant level of citric acid and polyvinyl alcohol (PVA (10% with different amounts of glycerol (GLY as a lubricating agent, crystal nanowhiskers (CNW and titanium dioxide (TiO2 nanoparticles were used together. Finally, the effects of these compounds on permeability properties of the obtained starch-based bionanocomposites were studied and their optimum values were determined by central composite design of response surface methodology (RSM. The results of X-Ray diffraction (XRD test showed that at low levels of TiO2 and CNW there was no diffractogram peak obtained. However, at high levels of TiO2 and CNW there emerged distinct and sharp peak which was attributed to greater crystalline region and probably non-homogeneity in particle distribution. The Fourier transmission infrared (FTIR data showed that addition of CNW and TiO2 increased hydrogen binding between the nanofillers and biopolymer matrix. The effects of TiO2 and CNW concentrations as quadratic and glycerol concentration as linear and quadratic were significant on water vapor permeability (WVP. The optimum levels of TiO2, CNW and GLY for obtaining minimum WVP corresponded to 0.118, 0.3 g and 1.06 mL, respectively.

  17. Satellite- and ground-based observations of atmospheric water vapor absorption in the 940 nm region

    International Nuclear Information System (INIS)

    Albert, P.; Smith, K.M.; Bennartz, R.; Newnham, D.A.; Fischer, J.

    2004-01-01

    Ground-based measurements of direct absorption of solar radiation between 9000 and 13,000 cm -1 (770-1100 nm) with a spectral resolution of 0.05 cm -1 are compared with line-by-line simulations of atmospheric absorption based on different molecular databases (HITRAN 2000, HITRAN 99, HITRAN 96 and ESA-WVR). Differences between measurements and simulations can be reduced to a great amount by scaling the individual line intensities with spectral and database dependent scaling factors. Scaling factors are calculated for the selected databases using a Marquardt non-linear least-squares fit together with a forward model for 100 cm -1 wide intervals between 10,150 and 11,250 cm -1 as well as for the water vapor absorption channels of the Medium Resolution Imaging Spectrometer (MERIS) onboard the European Space Agency's (ESA) ENVISAT platform and the Modular Optoelectronic Scanner (MOS) on the Indian IRSP-3 platform, developed by the German Aerospace Centre (DLR). For the latter, the scaling coefficients are converted into correction factors for retrieved total columnar water vapor content and used for a comparison of MOS-based retrievals of total columnar atmospheric water vapor above cloud-free land surfaces with radio soundings. The scaling factors determined for 100 cm -1 wide intervals range from 0.85 for the ESA-WVR molecular database to 1.15 for HITRAN 96. The best agreement between measurements and simulations is achieved with HITRAN 99 and HITRAN 2000, respectively, using scaling factors between 0.9 and 1. The effects on the satellite-based retrievals of columnar atmospheric water vapor range from 2% (HITRAN 2000) to 12% (ESA-WVR)

  18. Water vapor radiative effects on short-wave radiation in Spain

    Science.gov (United States)

    Vaquero-Martínez, Javier; Antón, Manuel; Ortiz de Galisteo, José Pablo; Román, Roberto; Cachorro, Victoria E.

    2018-06-01

    In this work, water vapor radiative effect (WVRE) is studied by means of the Santa Barbara's Disort Radiative Transfer (SBDART) model, fed with integrated water vapor (IWV) data from 20 ground-based GPS stations in Spain. Only IWV data recorded during cloud-free days (selected using daily insolation data) were used in this study. Typically, for SZA = 60.0 ± 0.5° WVRE values are around - 82 and - 66 Wm-2 (first and third quartile), although it can reach up - 100 Wm-2 or decrease to - 39 Wm-2. A power dependence of WVRE on IWV and cosine of solar zenith angle (SZA) was found by an empirical fit. This relation is used to determine the water vapor radiative efficiency (WVEFF = ∂WVRE/∂IWV). Obtained WVEFF values range from - 9 and 0 Wm-2 mm-1 (- 2.2 and 0% mm-1 in relative terms). It is observed that WVEFF decreases as IWV increases, but also as SZA increases. On the other hand, when relative WVEFF is calculated from normalized WVRE, an increase of SZA results in an increase of relative WVEFF. Heating rates were also calculated, ranging from 0.2 Kday-1 to 1.7 Kday-1. WVRE was also calculated at top of atmosphere, where values ranged from 4 Wm-2 to 37 Wm-2.

  19. Correction Technique for Raman Water Vapor Lidar Signal-Dependent Bias and Suitability for Water Wapor Trend Monitoring in the Upper Troposphere

    Science.gov (United States)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; hide

    2012-01-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper

  20. Compact Water Vapor Exchanger for Regenerative Life Support Systems

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Anderson, Molly; Hodgson, Edward

    2012-01-01

    Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Regenerative CO2 removal systems are attractive for these missions because they do not use consumable CO2 absorbers. However, these systems also absorb and vent water to space along with carbon dioxide. This paper describes an innovative device designed to minimize water lost from regenerative CO2 control systems. Design studies and proof-of-concept testing have shown the feasibility of a compact, efficient membrane water vapor exchanger (WVX) that will conserve water while meeting challenging requirements for operation on future spacecraft. Compared to conventional WVX designs, the innovative membrane WVX described here has the potential for high water recovery efficiency, compact size, and very low pressure losses. The key innovation is a method for maintaining highly uniform flow channels in a WVX core built from water-permeable membranes. The proof-of-concept WVX incorporates all the key design features of a prototypical unit, except that it is relatively small scale (1/23 relative to a unit sized for a crew of six) and some components were fabricated using non-prototypical methods. The proof-of-concept WVX achieved over 90% water recovery efficiency in a compact core in good agreement with analysis models. Furthermore the overall pressure drop is very small (less than 0.5 in. H2O, total for both flow streams) and meets requirements for service in environmental control and life support systems on future spacecraft. These results show that the WVX provides very uniform flow through flow channels for both the humid and dry streams. Measurements also show that CO2 diffusion through the water-permeable membranes will have negligible effect on the CO2 partial pressure in the spacecraft atmosphere.

  1. Galactic water vapor emission: further observations of variability.

    Science.gov (United States)

    Knowles, S H; Mayer, C H; Sullivan, W T; Cheung, A C

    1969-10-10

    Recent observations of the 1.35-centimeter line emission of water vapor from galactic sources show short-term variability in the spectra of several sources. Two additional sources, Cygnus 1 and NGC 6334N, have been observed, and the spectra of W49 and VY Canis Majoris were measured over a wider range of radial velocity.

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

    Science.gov (United States)

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

    1999-01-01

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

  3. Retrieval of water vapor vertical distributions in the upper troposphere and the lower stratosphere from SCIAMACHY limb measurements

    Directory of Open Access Journals (Sweden)

    A. Rozanov

    2011-05-01

    Full Text Available This study describes the retrieval of water vapor vertical distributions in the upper troposphere and lower stratosphere (UTLS altitude range from space-borne observations of the scattered solar light made in limb viewing geometry. First results using measurements from SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY aboard ENVISAT (Environmental Satellite are presented here. In previous publications, the retrieval of water vapor vertical distributions has been achieved exploiting either the emitted radiance leaving the atmosphere or the transmitted solar radiation. In this study, the scattered solar radiation is used as a new source of information on the water vapor content in the UTLS region. A recently developed retrieval algorithm utilizes the differential absorption structure of the water vapor in 1353–1410 nm spectral range and yields the water vapor content in the 11–25 km altitude range. In this study, the retrieval algorithm is successfully applied to SCIAMACHY limb measurements and the resulting water vapor profiles are compared to in situ balloon-borne observations. The results from both satellite and balloon-borne instruments are found to agree typically within 10 %.

  4. Water vapor mass balance method for determining air infiltration rates in houses

    Science.gov (United States)

    David R. DeWalle; Gordon M. Heisler

    1980-01-01

    A water vapor mass balance technique that includes the use of common humidity-control equipment can be used to determine average air infiltration rates in buildings. Only measurements of the humidity inside and outside the home, the mass of vapor exchanged by a humidifier/dehumidifier, and the volume of interior air space are needed. This method gives results that...

  5. An Accurate Method for Computing the Absorption of Solar Radiation by Water Vapor

    Science.gov (United States)

    Chou, M. D.

    1980-01-01

    The method is based upon molecular line parameters and makes use of a far wing scaling approximation and k distribution approach previously applied to the computation of the infrared cooling rate due to water vapor. Taking into account the wave number dependence of the incident solar flux, the solar heating rate is computed for the entire water vapor spectrum and for individual absorption bands. The accuracy of the method is tested against line by line calculations. The method introduces a maximum error of 0.06 C/day. The method has the additional advantage over previous methods in that it can be applied to any portion of the spectral region containing the water vapor bands. The integrated absorptances and line intensities computed from the molecular line parameters were compared with laboratory measurements. The comparison reveals that, among the three different sources, absorptance is the largest for the laboratory measurements.

  6. Availability of MCNP and MATLAB for reconstructing the water-vapor two-phase flow pattern in neutron radiography

    International Nuclear Information System (INIS)

    Feng Qixi; Feng Quanke; Takeshi, K.

    2008-01-01

    The China Advanced Research Reactor (CARR) is scheduled to be operated in the autumn of 2008. In this paper, we report preparations for installing the neutron radiography instrument (NRI) and for utilizing it efficiently. The 2-D relative neutron intensity profiles for the water-vapor two-phase flow inside the tube were obtained using the MCNP code without influence of γ-ray and electronic-noise. The MCNP simulation of the 2-D neutron intensity profile for the water-vapor two-phase flow was demonstrated. The simulated 2-D neutron intensity profiles could be used as the benchmark data base by calibrating part of the data measured by the CARR-NRI. The 3-D objective images allow us to understand the flow pattern more clearly and it is reconstructed using the MATLAB through the threshold transformation techniques. And thus it is concluded that the MCNP code and the MATLAB are very useful for constructing the benchmark data base for the investigation of the water-vapor two-phase flow using the CARR-NRI. (authors)

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

    Science.gov (United States)

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

    2017-11-01

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

  8. Liquid-phase and vapor-phase dehydration of organic/water solutions

    Science.gov (United States)

    Huang, Yu [Palo Alto, CA; Ly, Jennifer [San Jose, CA; Aldajani, Tiem [San Jose, CA; Baker, Richard W [Palo Alto, CA

    2011-08-23

    Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

  9. Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Westwater, Edgeworth

    2011-05-06

    The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of

  10. Trajectory mapping of middle atmospheric water vapor by a mini network of NDACC instruments

    Directory of Open Access Journals (Sweden)

    M. Lainer

    2015-08-01

    Full Text Available The important task to observe the global coverage of middle atmospheric trace gases like water vapor or ozone usually is accomplished by satellites. Climate and atmospheric studies rely upon the knowledge of trace gas distributions throughout the stratosphere and mesosphere. Many of these gases are currently measured from satellites, but it is not clear whether this capability will be maintained in the future. This could lead to a significant knowledge gap of the state of the atmosphere. We explore the possibilities of mapping middle atmospheric water vapor in the Northern Hemisphere by using Lagrangian trajectory calculations and water vapor profile data from a small network of five ground-based microwave radiometers. Four of them are operated within the frame of NDACC (Network for the Detection of Atmospheric Composition Change. Keeping in mind that the instruments are based on different hardware and calibration setups, a height-dependent bias of the retrieved water vapor profiles has to be expected among the microwave radiometers. In order to correct and harmonize the different data sets, the Microwave Limb Sounder (MLS on the Aura satellite is used to serve as a kind of traveling standard. A domain-averaging TM (trajectory mapping method is applied which simplifies the subsequent validation of the quality of the trajectory-mapped water vapor distribution towards direct satellite observations. Trajectories are calculated forwards and backwards in time for up to 10 days using 6 hourly meteorological wind analysis fields. Overall, a total of four case studies of trajectory mapping in different meteorological regimes are discussed. One of the case studies takes place during a major sudden stratospheric warming (SSW accompanied by the polar vortex breakdown; a second takes place after the reformation of stable circulation system. TM cases close to the fall equinox and June solstice event from the year 2012 complete the study, showing the high

  11. X-ray studies of the liquid/vapor interface: Water and polymer and fatty acid monolayers on water

    International Nuclear Information System (INIS)

    Schlossman, M.L.; Schwartz, D.K.; Kawamoto, E.H.; Kellogg, G.J.; Pershan, P.S.; Ocko, B.M.; Kim, M.W.; Chung, T.C.

    1989-01-01

    X-ray specular reflectivity is used to study the liquid-vapor interface of pure water and of fatty acid and polymer monolayers at that interface. For the pure water surface the reflectivity was measured for three different spectrometer resolutions and simultaneous fits with only one free parameter to all of the data are in excellent agreement with the prediction of capillary wave theory for the RMS surface roughness. Diffuse scattering away from the specular condition, at wavevectors corresponding to those of the capillary waves, yields intensities and line shapes in agreement with theory with no significant adjustable parameters. Reflectivity from separate monolayers of co-poly 1, 2-butadiene/butyl alcohol (50% random substitution) and lignoceric acid (CH 3 (CH 2 ) 22 COOH) at the water/vapor interface are interpreted to obtain profiles of the average electron density ρ(z) as a function of distance z along the surface normal. For the polymer monolayer we find the following: (1) a local maximum in the electron density approximately 10% larger than that of the bulk polymer and (2) the RMS roughness of the vapor/polymer interface agrees with capillary wave theory predictions for the lower surface pressures. For the highest surface pressure the RMS roughness exceeds the value predicted by the capillary wave model. Measurements of reflectivity from a lignoceric acid monolayer, as a function of surface pressure throughout an isotherm (near room temperature), reveal the following behavior: (1) the overall thickness of the monolayer increases with increasing pressure and (2) the head groups occupy a progressively larger region along the surface normal as the pressure increases, indicating that they rearrange normal to the interface. 15 refs., 5 figs., 2 tabs

  12. Characterization of photoluminescent (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3} thin-films prepared by metallorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    McKittrick, J.; Bacalski, C.F.; Hirata, G.A. [Univ. of California, San Diego, La Jolla, CA (United States); Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1998-12-01

    Europium doped yttrium oxide, (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3}, thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y{sub 2}O{sub 3}, grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y{sub 2}O{sub 3}:Eu{sup 3+} was observed in x-ray diffraction for deposition temperatures {ge}600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra.

  13. Water Vapor Adsorption on Biomass Based Carbons under Post-Combustion CO2 Capture Conditions: Effect of Post-Treatment

    Directory of Open Access Journals (Sweden)

    Nausika Querejeta

    2016-05-01

    Full Text Available The effect of post-treatment upon the H2O adsorption performance of biomass-based carbons was studied under post-combustion CO2 capture conditions. Oxygen surface functionalities were partially replaced through heat treatment, acid washing, and wet impregnation with amines. The surface chemistry of the final carbon is strongly affected by the type of post-treatment: acid treatment introduces a greater amount of oxygen whereas it is substantially reduced after thermal treatment. The porous texture of the carbons is also influenced by post-treatment: the wider pore volume is somewhat reduced, while narrow microporosity remains unaltered only after acid treatment. Despite heat treatment leading to a reduction in the number of oxygen surface groups, water vapor adsorption was enhanced in the higher pressure range. On the other hand acid treatment and wet impregnation with amines reduce the total water vapor uptake thus being more suitable for post-combustion CO2 capture applications.

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

    Science.gov (United States)

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

    2010-01-01

    LASE (Lidar Atmospheric Sensing Experiment) on-board the NASA DC-8 measured high resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern North Atlantic during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment. These measurements were used to study African easterly waves (AEWs), tropical cyclones (TCs), and the Saharan Air Layer(s) (SAL). Interactions between the SAL and tropical air were observed during the early stages of the TC development. These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its impact on AEWs and TCs. Examples of profile measurements of aerosol scattering ratios, aerosol extinction coefficients, aerosol optical thickness, water vapor mixing ratios, RH, and temperature are presented to illustrate their characteristics in SAL, convection, and clear air regions. LASE data suggest that the SAL suppresses low-altitude convection at the convection-SAL interface region. Mid-level convection associated with the AEW and transport are likely responsible for high water vapor content observed in the southern regions of the SAL on August 20, 2008. This interaction is responsible for the transfer of about 7 x 10(exp 15) J latent heat energy within a day to the SAL. Measurements of lidar extinction-to-backscatter ratios in the range 36+/-5 to 45+/-5 are within the range of measurements from other lidar measurements of dust. LASE aerosol extinction and water vapor profiles are validated by comparison with onboard in situ aerosol measurements and GPS dropsonde water vapor soundings, respectively.

  15. Nano-phases of ZrO2 doped with Y2O3

    International Nuclear Information System (INIS)

    Duteanu, Narcis; Monty, Claude

    2001-01-01

    This work reports the method of obtaining oxygen sensors by using nano-phases of ZrO 2 doped with Y 2 O 3 95% molar in thin layers. In the first phase it is necessary to prepare a substratum based on La 1-x Sr 30 MnO 3 . This substratum is obtained by grinding powders of base, followed by mixing and then by baking of the product. The nano-phases of ZrO 2 doped with Y 2 O 3 95% molar are obtained using solar energy in a solar furnace; in the focus the temperature has value of 3000 deg. C. Such temperatures are enough to realize the process of vapor condensation. The nano-phases obtained will have used in thin layers, representing the active element. This layers are obtained directly through the process of vapor condensation in solar focus or using the spray method. The goal of this work was obtaining oxygen sensors which function at low temperatures (below 300 deg. C), because the sensors which are found on market, operate at a temperature of 800 deg. C. Those sensors are used to obtain a good combustion with engines with internal combustion. (authors)

  16. Atmospheric solar heating rate in the water vapor bands

    Science.gov (United States)

    Chou, Ming-Dah

    1986-01-01

    The total absorption of solar radiation by water vapor in clear atmospheres is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are computed for individual absorption bands and for the total near-infrared region. The parameterization is based upon monochromatic calculations and follows essentially the scaling approximation of Chou and Arking, but the effect of temperature variation with height is taken into account in order to enhance the accuracy. Furthermore, the spectral range is extended to cover the two weak bands centered at 0.72 and 0.82 micron. Comparisons with monochromatic calculations show that the atmospheric heating rate and the surface radiation can be accurately computed from the parameterization. Comparisons are also made with other parameterizations. It is found that the absorption of solar radiation can be computed reasonably well using the Goody band model and the Curtis-Godson approximation.

  17. African and Atlantic short-term climatic variations described from Meteosat water vapor channel

    Directory of Open Access Journals (Sweden)

    L. Picon

    1995-07-01

    Full Text Available Pluriannual series of Meteosat-2 water vapor (WV images are used to build average maps of decadal and monthly brightness temperatures in the 6.3 µm channel. This processing is applied to all the 3-hourly scenes, clear or cloudy, for July 1983 to July 1987. The ISCCP cloudiness analyses confirm that the warmest spots in the monthly WV images correspond to scenes either clear or covered with low clouds, whereas the coldest areas correspond to scenes where cloud tops above 440 hPa frequently occur. The WV statistics are then used to characterize seasonal and interannual variations of both the ITCZ (InterTropical Convergence Zone and the warm (dry areas, corresponding to subtropical subsidence. Thanks mainly to the seasonal variations, relationships between the variations in the ITCZ and in dry subtropical areas can be studied. It is shown that, for the Meteosat sector, a wetter subtropical high troposphere is associated with an enhanced activity of the ITCZ, and vice versa. For this area where the north-south assymetry is large, the negative water vapor feedback previously proposed seems not to occur.

  18. Scanning Raman lidar for tropospheric water vapor profiling and GPS path delay correction

    Science.gov (United States)

    Tarniewicz, Jerome; Bock, Olivier; Pelon, Jacques R.; Thom, Christian

    2002-01-01

    The design of a ground based and transportable combined Raman elastic-backscatter lidar for the remote sensing of lower tropospheric water vapor and nitrogen concentration is described. This lidar is intended to be used for an external calibration of the wet path delay of GPS signals. A description of the method used to derive water vapor and nitrogen profiles in the lower troposphere is given. The instrument has been tested during the ESCOMPTE campaign in June 2001 and first measurements are presented.

  19. Removal of diethyl phthalate from water solution by adsorption, photo-oxidation, ozonation and advanced oxidation process (UV/H{sub 2}O{sub 2}, O{sub 3}/H{sub 2}O{sub 2} and O{sub 3}/activated carbon)

    Energy Technology Data Exchange (ETDEWEB)

    Medellin-Castillo, Nahum A. [Centro de Investigacion y Estudios de Posgrado, Facultad de Ingenieria, Universidad Autonoma de San Luis Potosi, Av. Dr. M. Nava No.6, San Luis de Potosi, 78290 (Mexico); Ocampo-Perez, Raul [Centro de Investigacion y Estudios de Posgrado, Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, San Luis Potosi, 78290 (Mexico); Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain); Leyva-Ramos, Roberto [Centro de Investigacion y Estudios de Posgrado, Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, San Luis Potosi, 78290 (Mexico); Sanchez-Polo, Manuel [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain); Rivera-Utrilla, Jose, E-mail: jrivera@ugr.es [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain); Mendez-Diaz, Jose D. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Granada, 18071, Granada (Spain)

    2013-01-01

    The objective of this work was to compare the effectiveness of conventional technologies (adsorption on activated carbon, AC, and ozonation) and technologies based on advanced oxidation processes, AOPs, (UV/H{sub 2}O{sub 2}, O{sub 3}/AC, O{sub 3}/H{sub 2}O{sub 2}) to remove phthalates from aqueous solution (ultrapure water, surface water and wastewater). Diethyl phthalate (DEP) was chosen as a model pollutant because of its high water solubility (1080 mg/L at 293 K) and toxicity. The activated carbons showed a high adsorption capacity to adsorb DEP in aqueous solution (up to 858 mg/g), besides the adsorption mechanism of DEP on activated carbon is governed by dispersive interactions between {pi} electrons of its aromatic ring with {pi} electrons of the carbon graphene planes. The photodegration process showed that the pH solution does not significantly affect the degradation kinetics of DEP and the first-order kinetic model satisfactorily fitted the experimental data. It was observed that the rate of decomposition of DEP with the O{sub 3}/H{sub 2}O{sub 2} and O{sub 3}/AC systems is faster than that with only O{sub 3}. The technologies based on AOPs (UV/H{sub 2}O{sub 2}, O{sub 3}/H{sub 2}O{sub 2}, O{sub 3}/AC) significantly improve the degradation of DEP compared to conventional technologies (O{sub 3}, UV). AC adsorption, UV/H{sub 2}O{sub 2}, O{sub 3}/H{sub 2}O{sub 2}, and O{sub 3}/AC showed a high yield to remove DEP; however, the disadvantage of AC adsorption is its much longer time to reach maximum removal. The best system to treat water (ultrapure and natural) polluted with DEP is the O{sub 3}/AC one since it achieved the highest DEP degradation and TOC removal, as well as the lower water toxicity. -- Highlights: Black-Right-Pointing-Pointer Activated carbons showed a high adsorption capacity (up to 858 mg/g) to remove DEP. Black-Right-Pointing-Pointer The pH solution did not significantly affect the photodegradation kinetics of DEP. Black

  20. High performance LiNi0.5Mn1.5O4 cathode by Al-coating and Al3+-doping through a physical vapor deposition method

    International Nuclear Information System (INIS)

    Sun, Peng; Ma, Ying; Zhai, Tianyou; Li, Huiqiao

    2016-01-01

    Highlights: • Metal Al was used as an electrical conductive coating material for LiNi 0.5 Mn 1.5 O 4 . • The uniform surface coating layer of metal Al was successfully achieved with adjusted thickness through a physical vapor deposition technology. • Al 3+ -doped LiNi 0.5 Mn 1.5 O 4 can be easily obtained by further directly annealing of Al-coated LiNi 0.5 Mn 1.5 O 4 in air. • The conductive Al-coating layer can greatly improve the rate performance and cycle stability of LiNi 0.5 Mn 1.5 O 4 . - Abstract: In this work, spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) hollow microspheres are synthesized by an impregnation method using microsphere MnO 2 as both the precursor and template. To enhance the electrical conductivity of LNMO, metal Al was employed for the first time as a coating material for LNMO. Though an Electron-beam Vapor Deposition approach, the surface of LNMO can be easily coated by a tight layer of Al nanoparticles with adjusted thickness. Further annealing the Al-coated sample at 800 °C in air, the Al 3+ -doped LNMO can be obtained. The effects of Al-coating and Al 3+ -doping on the sample morphology and structure are investigated by SEM, TEM, XRD and FT-IR. The electrochemical properties of Al-coated LNMO and Al 3+ -doped LNMO are measured with comparison of bare LNMO by charge/discharge tests and electrochemical impedance spectroscopy (EIS). The results show that both Al-coating and Al 3+ -doping can greatly enhance the cycle performance and rate capability of LNMO. Especially for Al-coated LNMO, it shows the lowest battery impedance due to the existence of conductive Al coating layer, thus delivers the best rate performance among the three. The physical coating procedure used in this work may provide a new facile modification approach for other cathode materials.

  1. Condensation heat transfer correlation for water-ethanol vapor mixture flowing through a plate heat exchanger

    Science.gov (United States)

    Zhou, Weiqing; Hu, Shenhua; Ma, Xiangrong; Zhou, Feng

    2018-04-01

    Condensation heat transfer coefficient (HTC) as a function of outlet vapor quality was investigated using water-ethanol vapor mixture of different ethanol vapor concentrations (0%, 1%, 2%, 5%, 10%, 20%) under three different system pressures (31 kPa, 47 kPa, 83 kPa). A heat transfer coefficient was developed by applying multiple linear regression method to experimental data, taking into account the dimensionless numbers which represents the Marangoni condensation effects, such as Re, Pr, Ja, Ma and Sh. The developed correlation can predict the condensation performance within a deviation range from -22% to 32%. Taking PHE's characteristic into consideration and bringing in Ma number and Sh number, a new correlation was developed, which showed a much more accurate prediction, within a deviation from -3.2% to 7.9%.

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

    Science.gov (United States)

    Tsai, C. Y.

    1998-01-01

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

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

    Science.gov (United States)

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

    1977-01-01

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

  4. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  5. On the cross-sensitivity between water vapor mixing ratio and stable isotope measurements of in-situ analyzers

    KAUST Repository

    Parkes, Stephen; Wang,  Lixin; McCabe, Matthew

    2015-01-01

    In recent years there has been an increasing amount of water vapor stable isotope data collected using in-situ instrumentation. A number of papers have characterized the performance of these in-situ analyzers and suggested methods for calibrating raw measurements. The cross-sensitivity of the isotopic measurements on the mixing ratio has been shown to be a major uncertainty and a variety of techniques have been suggested to characterize this inaccuracy. However, most of these are based on relating isotopic ratios to water vapor mixing ratios from in-situ analyzers when the mixing ratio is varied and the isotopic composition kept constant. An additional correction for the span of the isotopic ratio scale is then applied by measuring different isotopic standards. Here we argue that the water vapor cross-sensitivity arises from different instrument responses (span and offset) of the parent H2O isotope and the heavier isotopes, rather than spectral overlap that could cause a true variation in the isotopic ratio with mixing ratio. This is especially relevant for commercial laser optical instruments where absorption lines are well resolved. Thus, the cross-sensitivity determined using more conventional techniques is dependent on the isotopic ratio of the standard used for the characterization, although errors are expected to be small. Consequently, the cross-sensitivity should be determined by characterizing the span and zero offset of each isotope mixing ratio. In fact, this technique makes the span correction for the isotopic ratio redundant. In this work we model the impact of changes in the span and offset of the heavy and light isotopes and illustrate the impact on the cross-sensitivity of the isotopic ratios on water vapor. This clearly shows the importance of determining the zero offset for the two isotopes. The cross-sensitivity of the isotopic ratios on water vapor is then characterized by determining the instrument response for the individual isotopes for a

  6. Assessing interactions of hydrophilic nanoscale TiO{sub 2} with soil water

    Energy Technology Data Exchange (ETDEWEB)

    Priester, John H.; Ge, Yuan; Chang, Vivian [University of California, Santa Barbara, Bren School of Environmental Science and Management (United States); Stoimenov, Peter K. [University of California, Santa Barbara, Department of Chemistry and Biochemistry (United States); Schimel, Joshua P. [University of California, Santa Barbara, Earth Research Institute (United States); Stucky, Galen D. [University of California, Santa Barbara, UC Center for the Environmental Implications of Nanotechnology (United States); Holden, Patricia A., E-mail: holden@bren.ucsb.edu [University of California, Santa Barbara, Bren School of Environmental Science and Management (United States)

    2013-09-15

    The implications of manufactured nanoscale materials (MNMs) in unsaturated soil are mostly unknown. Owing to its widespread use, nanoscale (n) TiO{sub 2} is expected to enter soils where its accumulation could impact soil processes. Yet fundamental information is lacking regarding nTiO{sub 2} in situ wettability, i.e., interactions with soil water that relate to nTiO{sub 2} exposure and bioavailability. To probe nTiO{sub 2} interactions with soil water, we amended a natural soil with 20 mg per g of P25 nTiO{sub 2}, a high-production, hydrophilic MNM that, based on its small size (25 nm nominal), provides ample specific surface area (SSA) for water sorption. We then measured nTiO{sub 2}-amended soil SSA, and conducted a dynamic water vapor conditioning experiment. Early time-course water sorption into soil, with and without nTiO{sub 2}, was clearly diffusional. Over 9 months, soil water content asymptotically equilibrated. However, despite amending with nTiO{sub 2} levels that increased the soil SSA by 16 %, measured water sorption rates and endpoint soil water contents were mostly unchanged by P25 nTiO{sub 2}. Our results indicate that as-manufactured hydrophilic P25 nTiO{sub 2} was hydrophobic in soil, a finding relevant to nTiO{sub 2} bioavailability and transport.

  7. Using JPSS Retrievals to Implement a Multisensor, Synoptic, Layered Water Vapor Product for Forecasters

    Science.gov (United States)

    Forsythe, J. M.; Jones, A. S.; Kidder, S. Q.; Fuell, K.; LeRoy, A.; Bikos, D.; Szoke, E.

    2015-12-01

    Forecasters have been using the NOAA operational blended total precipitable water (TPW) product, developed by the Cooperative Institute for Research in the Atmosphere (CIRA), since 2009. Blended TPW has a wide variety of uses related to heavy precipitation and flooding, such as measuring the amount of moisture in an atmospheric river originating in the tropics. But blended TPW conveys no information on the vertical distribution of moisture, which is relevant to a variety of forecast concerns. Vertical profile information is particularly lacking over the oceans for landfalling storms. A blended six-satellite, four-layer, layered water vapor product demonstrated by CIRA and the NASA Short-term Prediction Research and Transition Center (SPoRT) in allows forecasters to see the vertical distribution of water vapor in near real-time. National Weather Service (NWS) forecaster feedback indicated that this new, vertically-resolved view of water vapor has a substantial impact on forecasts. This product uses NOAA investments in polar orbiting satellite sounding retrievals from passive microwave radiances, in particular, the Microwave Integrated Retrieval System (MIRS). The product currently utilizes data from the NOAA-18 and -19 spacecraft, Metop-A and -B, and the Defense Meteorological Program (DMSP) F18 spacecraft. The sounding instruments onboard the Suomi-NPP and JPSS spacecraft will be cornerstone instruments in the future evolution of this product. Applications of the product to heavy rain cases will be presented and compared to commonly used data such as radiosondes and Geostationary Operational Environmental Satellite (GOES) water vapor channel imagery. Research is currently beginning to implement advective blending, where model winds are used to move the water vapor profiles to a common time. Interactions with the NOAA Satellite Analysis Branch (SAB), National Center for Environmental Prediction (NCEP) centers including the Ocean Prediction Center (OPC) and Weather

  8. A decadal time series of water vapor and D / H isotope ratios above Zugspitze: transport patterns to central Europe

    Science.gov (United States)

    Hausmann, Petra; Sussmann, Ralf; Trickl, Thomas; Schneider, Matthias

    2017-06-01

    We present vertical soundings (2005-2015) of tropospheric water vapor (H2O) and its D / H isotope ratio (δD) derived from ground-based solar Fourier transform infrared (FTIR) measurements at Zugspitze (47° N, 11° E, 2964 m a.s.l.). Beside water vapor profiles with optimized vertical resolution (degrees of freedom for signal, DOFS, = 2.8), {H2O, δD} pairs with consistent vertical resolution (DOFS = 1.6 for H2O and δD) applied in this study. The integrated water vapor (IWV) trend of 2.4 [-5.8, 10.6] % decade-1 is statistically insignificant (95 % confidence interval). Under this caveat, the IWV trend estimate is conditionally consistent with the 2005-2015 temperature increase at Zugspitze (1.3 [0.5, 2.1] K decade-1), assuming constant relative humidity. Seasonal variations in free-tropospheric H2O and δD exhibit amplitudes of 140 and 50 % of the respective overall means. The minima (maxima) in January (July) are in agreement with changing sea surface temperature of the Atlantic Ocean. Using extensive backward-trajectory analysis, distinct moisture pathways are identified depending on observed δD levels: low column-based δD values (δDcol 95th percentile: 46° N, 4.6 km). Backward-trajectory classification indicates that {H2O, δD} observations are influenced by three long-range-transport patterns towards Zugspitze assessed in previous studies: (i) intercontinental transport from North America (TUS; source region: 25-45° N, 70-110° W, 0-2 km altitude), (ii) intercontinental transport from northern Africa (TNA; source region: 15-30° N, 15° W-35° E, 0-2 km altitude), and (iii) stratospheric air intrusions (STIs; source region: > 20° N, above zonal mean tropopause). The FTIR data exhibit significantly differing signatures in free-tropospheric {H2O, δD} pairs (5 km a.s.l.) - given as the mean with uncertainty of ±2 standard error (SE) - for TUS (VMRH2O = 2.4 [2.3, 2.6] × 103 ppmv, δD = -315 [-326, -303] ‰), TNA (2.8 [2.6, 2.9] × 103 ppmv, -251 [-257

  9. Characterization of Pb(Zr, Ti)O sub 3 thin films prepared by metal-organic chemical-vapor deposition using a solid delivery system

    CERN Document Server

    Shin, J C; Hwang, C S; Kim, H J; Lee, J M

    1999-01-01

    Pb(Zr, Ti)O sub 3 (PZT) thin films were deposited on Pt/SiO sub 2 /Si substrates by metal-organic chemical-vapor deposition technique using a solid delivery system to improve the reproducibility of the deposition. The self-regulation mechanism, controlling the Pb-content of the film, was observed to work above a substrate temperature of 620 .deg. C. Even with the self-regulation mechanism, PZT films having low leakage current were obtained only when the molar mixing ratio of the input precursors was 1

  10. Water liquid-vapor interface subjected to various electric fields: A molecular dynamics study

    Science.gov (United States)

    Nikzad, Mohammadreza; Azimian, Ahmad Reza; Rezaei, Majid; Nikzad, Safoora

    2017-11-01

    Investigation of the effects of E-fields on the liquid-vapor interface is essential for the study of floating water bridge and wetting phenomena. The present study employs the molecular dynamics method to investigate the effects of parallel and perpendicular E-fields on the water liquid-vapor interface. For this purpose, density distribution, number of hydrogen bonds, molecular orientation, and surface tension are examined to gain a better understanding of the interface structure. Results indicate enhancements in parallel E-field decrease the interface width and number of hydrogen bonds, while the opposite holds true in the case of perpendicular E-fields. Moreover, perpendicular fields disturb the water structure at the interface. Given that water molecules tend to be parallel to the interface plane, it is observed that perpendicular E-fields fail to realign water molecules in the field direction while the parallel ones easily do so. It is also shown that surface tension rises with increasing strength of parallel E-fields, while it reduces in the case of perpendicular E-fields. Enhancement of surface tension in the parallel field direction demonstrates how the floating water bridge forms between the beakers. Finally, it is found that application of external E-fields to the liquid-vapor interface does not lead to uniform changes in surface tension and that the liquid-vapor interfacial tension term in Young's equation should be calculated near the triple-line of the droplet. This is attributed to the multi-directional nature of the droplet surface, indicating that no constant value can be assigned to a droplet's surface tension in the presence of large electric fields.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  12. Climate Change Intensification of Horizontal Water Vapor Transport in CMIP5

    Science.gov (United States)

    Lavers, D. A.; Ralph, F. M.; Waliser, D. E.; Gershunov, A.; Dettinger, M. D.

    2015-12-01

    The global water cycle is hypothesized to intensify with a warming Earth's atmosphere. To determine associated hydrological changes, most previous research has used precipitation scenarios without considering changes to the horizontal water vapor transport (IVT). As few studies have analyzed the IVT, and given that many extreme precipitation and flood events are driven by intense water vapor transport, it is the aim of this study to investigate projected changes to global IVT. Furthermore, this approach can identify climatological changes to the IVT between water source and sink regions. Using 22 global circulation models from the Climate Model Intercomparison Project Phase 5 (CMIP5) we evaluate, globally, the mean, standard deviation, and the 95th percentile of IVT from the historical simulations (1979-2005) and two emissions scenarios (2073-2099); representative concentration pathways (RCP4.5 and RCP8.5). This analysis is undertaken for December, January, and February (Boreal winter); and for June, July, and August (Austral winter). The CMIP5 historical multi-model mean has good agreement with the fields from the ECMWF ERA-Interim reanalysis, which provides confidence in the models' signal. In the future, under more extreme emissions (RCP8.5), multi-model mean IVT increases by 30-40% in the North Pacific and North Atlantic storm tracks and in the equatorial Pacific Ocean trade winds. The Arctic region has the largest relative IVT increase especially in Boreal winter. Analysis of low-altitude moisture and winds suggest that these projected changes are mainly due to higher atmospheric water vapor content.

  13. Total absorption and photoionization cross sections of water vapor between 100 and 1000 A

    Science.gov (United States)

    Haddad, G. N.; Samson, J. A. R.

    1986-01-01

    Absolute photoabsorption and photoionization cross sections of water vapor are reported at a large number of discrete wavelengths between 100 and 1000 A with an estimate error of + or - 3 percent in regions free from any discrete structure. The double ionization chamber technique utilized is described. Recent calculations are shown to be in reasonable agreement with the present data.

  14. Tracking atmospheric boundary layer dynamics with water vapor D-excess observations

    KAUST Repository

    Parkes, Stephen

    2015-04-01

    Stable isotope water vapor observations present a history of hydrological processes that have impacted on an air mass. Consequently, there is scope to improve our knowledge of how different processes impact on humidity budgets by determining the isotopic end members of these processes and combining them with in-situ water vapor measurements. These in-situ datasets are still rare and cover a limited geographical expanse, so expanding the available data can improve our ability to define isotopic end members and knowledge about atmospheric humidity dynamics. Using data collected from an intensive field campaign across a semi-arid grassland site in eastern Australia, we combine multiple methods including in-situ stable isotope observations to study humidity dynamics associated with the growth and decay of the atmospheric boundary layer and the stable nocturnal boundary layer. The deuterium-excess (D-excess) in water vapor is traditionally thought to reflect the sea surface temperature and relative humidity at the point of evaporation over the oceans. However, a number of recent studies suggest that land-atmosphere interactions are also important in setting the D-excess of water vapor. These studies have shown a highly robust diurnal cycle for the D-excess over a range of sites that could be exploited to better understand variations in atmospheric humidity associated with boundary layer dynamics. In this study we use surface radon concentrations as a tracer of surface layer dynamics and combine these with the D-excess observations. The radon concentrations showed an overall trend that was inversely proportional to the D-excess, with early morning entrainment of air from the residual layer of the previous day both diluting the radon concentration and increasing the D-excess, followed by accumulation of radon at the surface and a decrease in the D-excess as the stable nocturnal layer developed in the late afternoon and early evening. The stable nocturnal boundary layer

  15. Velocity profile of water vapor inside a cavity with two axial inlets and two outlets

    Science.gov (United States)

    Guadarrama-Cetina, José; Ruiz Chavarría, Gerardo

    2014-03-01

    To study the dynamics of Breath Figure phenomenon, a control of both the rate of flow and temperature of water vapor is required. The experimental setup widely used is a non hermetically closed chamber with cylindrical geometry and axial inlets and outlets. In this work we present measurements in a cylindrical chamber with diameter 10 cm and 1.5 cm height, keeping a constant temperature (10 °C). We are focused in the velocity field when a gradient of the temperatures is produced between the base plate and the vapor. With a flux of water vapor of 250 mil/min at room temperature (21 °C), the Reynolds number measured in one inlet is 755. Otherwise, the temperatures of water vapor varies from 21 to 40 °C. The velocity profile is obtained by hot wire anemometry. We identify the stagnations and the possibly instabilities regions for an empty plate and with a well defined shape obstacle as a fashion sample. Facultad de Ciencias, UNAM.

  16. A systemic study of stepwise chlorination-chemical vapor transport characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by alkaline chlorides as complex former

    International Nuclear Information System (INIS)

    Sun Yanhui; He Peng; Chen Huani

    2007-01-01

    A systematic study has been carried out for the stepwise chlorination-chemical vapor transport (SC-CVT) characteristics of pure rare earth oxides from Sc 2 O 3 to Lu 2 O 3 mediated by the vapor complexes KLnCl 4 and NaLnCl 4 (Ln = Sc, Y and La-Lu) used NaCl and KCl as complex former, respectively. The results showed that the SC-CVT characteristics are similarly for NaCl and KCl as complex former, the main deposition temperature of the rare earth chlorides LnCl 3 is in the increasing order ScCl 3 3 3 , and then with a systematically decreasing trend from the early lanthanide chlorides to the end one. The results also showed that the total transported amount of the produced chlorides is YCl 3 > ScCl 3 , and they are much higher than that of most lanthanoid chlorides. For lanthanoids, the total transported amount of chloride increases systematically from the early lanthanoid chlorides to the end one except for EuCl 3 and GdCl 3 mediated by KCl and NaCl as complex former, respectively, which showed the divergence effect of Gd in the total transport efficiency. But there are some differences in SC-CVT characteristics of pure rare earth oxide mediated by KCl and NaCl as complex former, that is the main deposition temperature region for the same rare earth element was lower for KCl than that for NaCl as complex former except for LaCl 3 , CeCl 3 , YbCl 3 and LuCl 3 , while the total transport amount of rare earth chloride for KCl as complex former is higher than that for NaCl except for LaCl 3 and EuCl 3 . More over, the discussion was carried out for Sc and Y on the one hand and the lanthanides contain 4f electron as another hand based on the 4f electron hybridization assumption. Further more, the transport characteristics of rare earth oxides with alkaline chlorides as complex former in this study were compared to that with AlCl 3 as complex former

  17. Experimental investigation and modeling of adsorption of water and ethanol on cornmeal in an ethanol-water binary vapor system

    Energy Technology Data Exchange (ETDEWEB)

    Chang, H.; Yuan, X.G.; Tian, H.; Zeng, A.W. [State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072 (China)

    2006-04-15

    The adsorption capacity of water and ethanol on cornmeal in an ethanol-water binary vapor system was investigated in a fixed-bed apparatus for ethanol dehydration. Experiments were performed at temperatures of 82-100 C for different relative humidities of ethanol-water vapor. Adsorption equilibrium models, including those based on the adsorption potential theory of Polanyi and Sircar's model, have been used to fit the experimental data for water adsorption on cornmeal, and all gave good fits. For ethanol adsorption, pseudo-equilibrium was defined as the mass adsorbed on the cornmeal within the time needed for the equilibrium for water on the same adsorbent. Based on this limiting condition, adsorption behaviors and mechanisms were analyzed. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  18. Evidence of non-LTE Effects in Mesospheric Water Vapor from Spectrally-Resolved Emissions Observed by CIRRIS-1A

    Science.gov (United States)

    Zhou, D. K.; Mlynczak, M. G.; Lopez-Puertas, M.; Zaragoza, G.

    1999-01-01

    Evidence of non-LTE effects in mesospheric water vapor as determined by infrared spectral emission measurements taken from the space shuttle is reported. A cryogenic Michelson interferometer in the CIRRIS-1A shuttle payload yielded high quality, atmospheric infrared spectra. These measurements demonstrate the enhanced daytime emissions of H2O (020-010) which are the result of non-LTE processes and in agreement with non-LTE models. The radiance ratios of H2O (010 to 000) and (020 to 010) Q(1) transitions during daytime are compared with non-LTE model calculations to assess the vibration-to-vibration exchange rate between H2O and O2 in the mesosphere. An exchange rate of 1.2 x 10(exp -12)cc/s is derived.

  19. Monitoring the variability of precipitable water vapor over the Klang Valley, Malaysia during flash flood

    International Nuclear Information System (INIS)

    Suparta, W; Rahman, R; Singh, M S J

    2014-01-01

    Klang Valley is a focal area of Malaysian economic and business activities where the local weather condition is very important to maintain its reputation. Heavy rainfalls for more than an hour were reported up to 40 mm in September 2013 and 35 mm in October 2013. Both events are monitored as the first and second cases of flash flood, respectively. Based on these cases, we investigate the water vapor, rainfall, surface meteorological data (surface pressure, relative humidity, and temperature) and river water level. The precipitable water vapor (PWV) derived from Global Positioning System (GPS) is used to indicate the impact of flash flood on the rainfall. We found that PWV was dropped 4 mm in 2 hours before rainfall reached to 40 mm and dropped 3 mm in 3 hours before 35 mm of rainfall in respective cases. Variation of PWV was higher in September case compared to October case of about 2 mm. We suggest the rainfall phenomena can disturb the GPS propagation and therefore, the impact of PWV before, during and after the flash flood event at three selected GPS stations in Klang Valley is investigated for possible mitigation in the future

  20. Extending water vapor trend observations over Boulder into the tropopause region: Trend uncertainties and resulting radiative forcing

    Science.gov (United States)

    Kunz, A.; Müller, R.; Homonnai, V.; Jánosi, I. M.; Hurst, D.; Rap, A.; Forster, P. M.; Rohrer, F.; Spelten, N.; Riese, M.

    2013-10-01

    Thirty years of balloon-borne measurements over Boulder (40°N,105°W) are used to investigate the water vapor trend in the tropopause region. This analysis extends previously published trends, usually focusing on altitudes greater than 16 km, to lower altitudes. Two new concepts are applied: (1) Trends are presented in a thermal tropopause (TP) relative coordinate system from -2 km below to 10 km above the TP, and (2) sonde profiles are selected according to TP height. Tropical (TPz>14km), extratropical (TPzconcepts reduces the dynamically induced water vapor variability at the TP and principally favors refined water vapor trend studies in the upper troposphere and lower stratosphere. Nonetheless, this study shows how uncertain trends are at altitudes -2 to +4 km around the TP. This uncertainty in turn has an influence on the uncertainty and interpretation of water vapor radiative effects at the TP, which are locally estimated for the 30 year period to be of uncertain sign. The much discussed decrease in water vapor at the beginning of 2001 is not detectable between -2 and 2 km around the TP. On lower stratospheric isentropes, the water vapor change at the beginning of 2001 is more intense for extratropical than for tropical air mass types. This suggests a possible link with changing dynamics above the jet stream such as changes in the shallow branch of the Brewer-Dobson circulation.

  1. Rigorous determination of stratospheric water vapor trends from MIPAS observations.

    Science.gov (United States)

    Ceccherini, Simone; Carli, Bruno; Raspollini, Piera; Ridolfi, Marco

    2011-05-09

    The trend of stratospheric water vapor as a function of latitude is estimated by the MIPAS measurements by means of a new method that uses the measurement space solution. The method uses all the information provided by the observations avoiding the artifacts introduced by the a priori information and by the interpolation to different vertical grids. The analysis provides very precise values of the trends that, however, are limited by a relatively large systematic error induced by the radiometric calibration error of the instrument. The results show in the five years from 2005 to 2009 a dependence on latitude of the stratospheric (from 37 to 53 km) water vapor trend with a positive value of (0.41 ± 0.16)%yr-1 in the northern hemisphere and less than 0.16%yr-1 in the southern hemisphere.

  2. The Use of Water Vapor for Detecting Environments that Lead to Convectively Produced Heavy Precipitation and Flash Floods

    Science.gov (United States)

    Scofield, Rod; Vicente, Gilberto; Hodges, Mike

    2000-01-01

    This Tech Report summarizes years of study and experiences on using GOES Water vapor (6.7 micron and precipitable water) and Special Sensor Microwave Imager (SSM/1) from the Defense Meteorological Satellite Program (DMSP) derived Precipitable Water (PNAI) for detecting environments favorable for convectively produced flash floods. An emphasis is on the moisture. upper air flow, and equivalent potential temperature (Theta(sub e)) patterns that lead to devastating flood events. The 15 minute 6.7 micron water vapor imagery is essential for tracking middle to upper tropospheric disturbances that produce upward vertical motion and initiate flash flood producing systems. Water vapor imagery at 6.7 micron is also used to detect surges of upper level moisture (called tropical water vapor plumes) that have been associated with extremely heavy rainfall. Since the water vapor readily depicts lifting mechanisms and upper level moisture, water vapor imagery is often an excellent source of data for recognizing patterns of heavy precipitation and flash floods. In order to analyze the depth of the moisture, the PW aspects of the troposphere must be measured. The collocation (or nearby location) of high values ofP\\V and instability are antecedent conditions prior to the flash flood or heavy rainfall events. Knowledge of PW magnitudes have been used as thresholds for impending flash flood events, PW trends are essential in flash flood prediction. Conceptual models and water vapor products are used to study some of the characteristics of convective systems that occurred over the United States of America (USA) during the summer of 1997 and the 1997-1998 El Nino. P\\V plumes were associated with most of the \\vest coast heavy precipitation events examined during the winter season of 1997 - 1998, In another study, conducted during the summer season of 1997. results showed that the collocation of water vapor (6.7 micron) and P\\N' plumes possessed higher correlations with predicted

  3. Comparison of pharmaceutical abatement in various water matrices by conventional ozonation, peroxone (O3/H2O2), and an electro-peroxone process.

    Science.gov (United States)

    Wang, Huijiao; Zhan, Juhong; Yao, Weikun; Wang, Bin; Deng, Shubo; Huang, Jun; Yu, Gang; Wang, Yujue

    2018-03-01

    Pharmaceutical abatement in a groundwater (GW), surface water (SW), and secondary effluent (SE) by conventional ozonation, the conventional peroxone (O 3 /H 2 O 2 ), and the electro-peroxone (E-peroxone) processes was compared in batch tests. SE had significantly more fast-reacting dissolved organic matter (DOM) moieties than GW and SW. Therefore, O 3 decomposed much faster in SE than in GW and SW. At specific ozone doses of 0.5-1.5 mg O 3 /mg dissolved organic carbon (DOC), the application of O 3 /H 2 O 2 and E-peroxone process (by adding external H 2 O 2 stocks or in-situ generating H 2 O 2 from cathodic O 2 reduction during ozonation) similarly enhanced the OH yield from O 3 decomposition by ∼5-12% and 5-7% in GW and SW, respectively, compared to conventional ozonation. In contrast, due to the slower reaction kinetics of O 3 with H 2 O 2 than O 3 with fast-reacting DOM moieties, the addition or electro-generation of H 2 O 2 hardly increased the OH yield (<4% increases) in SE. Corresponding to the changes in the OH yields, the abatement efficiencies of ozone-resistant pharmaceuticals (ibuprofen and clofibric acid) increased evidently in GW (up to ∼14-18% at a specific ozone dose of 1.5 mg O 3 /mg DOC), moderately in SW (up to 6-10% at 0.5 mg O 3 /mg DOC), and negligibly in SE during the O 3 /H 2 O 2 and E-peroxone treatment compared to conventional ozonation. These results indicate that similar to the conventional O 3 /H 2 O 2 process, the E-peroxone process can more pronouncedly enhance O 3 transformation to OH, and thus increase the abatement efficiency of ozone-resistant pharmaceuticals in water matrices exerting relatively high ozone stability (e.g., groundwater and surface water with low DOM contents). Therefore, by installing electrodes in existing ozone reactors, the E-peroxone process may provide a convenient way to enhance pharmaceutical abatement in drinking water applications, where groundwater and surface water with low DOM contents are used as

  4. The Water Vapor Source and Transport Characteristic of Rainy Seasons in Eastern China Base on Lagrangian Method

    Science.gov (United States)

    Shi, Y.; Jiang, Z.; Liu, Z.; Li, L.

    2017-12-01

    The Hybrid Single-Particle Lagrangian Integrated Trajectory platform is employed in this studyto simulate trajectories of air parcels in the different rainy seasons in East China from 1961 to 2010,with the purpose of investigating general and specific characteristics of moisture sources and the eventual relationship withprecipitation in each rainy season.The moisture transport andsource-sink characteristics of different rainy seasons have evident differences. The results show that the frontal pre-rainy season is mainly influenced bywinter monsoon system, and the precipitation is strongly affected by water vapor from Pacific Ocean (PO) and East China (EC). Afterthe onset of South China Sea Summer Monsoon (SCSMS), the moisture from Pacific Ocean decreases and from Indian Ocean monsoon area increases. Afterwards, with the northward of the rain belt, the parcels from Southwest region (South China Sea (SCS), Indian Ocean (IO) andIndo-China Peninsula and Indian Peninsula(IP)) decrease and from North region (EC, Eurasia (EA) and PO) increase. Besides, most of the land areas are water vapor sink region and most of sea areas are water vapor source region. Before the onset of SCSMS, EC and PO are two main water vapor source areas.After the onset of SCSMS, the source from PO decreasesand Indian monsoon area becomes the main vapor source region. IP is the main water vapor sink area for all four rainy seasons.As for moisture circulation characteristics, the results of vertical structure of water vapor transport indicate that the maximum water vapor transport in west and east boundaries is located in mid-troposphere and in south and north boundaries is at low-troposphere. The spatiotemporal analysis of moisture trajectory based onmultivariate empirical orthogonal function (MVEOF) indicates that the first mode has close relationship with the precipitation in North China and PDO pattern; the second mode is closely related with the precipitation in Yangtze-Huaihe river basin and

  5. Characterization of RuO sub 2 electrodes for ferroelectric thin films prepared by metal-organic chemical-vapor deposition using Ru(C sub 1 sub 1 H sub 1 sub 9 O sub 2) sub 3

    CERN Document Server

    Lee, J M; Shin, J C; Hwang, C S; Kim, H J; Suk, C G

    1999-01-01

    Pure and conducting RuO sub 2 thin films were deposited on Si substrates at 250 approx 450 .deg. C using Ru(C sub 1 sub 1 H sub 1 sub 9 O sub 2) sub 3 as a precursor by low-pressure metal-organic chemical-vapor deposition (LP-MOCVD). At a lower deposition temperature,smoother and denser RuO sub 2 thin films were deposited. The RuO sub 2 thin films, which were crack free, adhered well onto the substrates and showed very low resistivities around 45 approx 60 mu OMEGA cm. RuO sub 2 thin films on (Ba, Sr)/TiO sub 3 /Pt/SiO sub 2 /Si showed good properties, indicating that MOCVD RuO sub 2 thin films from Ru(C sub 1 sub 1 H sub 1 sub 9 O sub 2) sub 3 can be applied as electrodes of high-dielectric thin films for capacitors in ultra-large-scale DRAMs.

  6. The impact of water vapor transmission rate on the lifetime of flexible polymer solar cells

    Science.gov (United States)

    Hauch, Jens A.; Schilinsky, Pavel; Choulis, Stelios A.; Rajoelson, Sambatra; Brabec, Christoph J.

    2008-09-01

    In this paper we perform accelerated lifetime testing on high efficiency flexible poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM) solar cells encapsulated with food package quality barrier films with a water vapor transmission rate of 0.2 g/(m2 day) at 65 °C/85% relative humidity. We show that lifetimes exceeding 1250 h, even at high temperature/high humidity conditions, may be reached, proving that organic solar cells are significantly less sensitive against the environmental effects of water and oxygen than previously expected.

  7. Isotopic composition of water in a deep unsaturated zone beside a radioactive-waste disposal area near Beatty, Nevada

    Science.gov (United States)

    Stonestrom, David A.; Prudic, David E.; Striegl, Robert G.; Morganwalp, David W.; Buxton, Herbert T.

    1999-01-01

    The isotopic composition of water in deep unsaturated zones is of interest because it provides information relevant to hydrologic processes and contaminant migration. Profiles of oxygen-18 (18O), deuterium (D), and tritium (3H) from a 110-meter deep unsaturated zone, together with data on the isotopic composition of ground water and modern-day precipitation, are interpreted in the context of water-content, water-potential, and pore-gas profiles. At depths greater than about three meters, water vapor and liquid water are in approximate equilibrium with respect to D and 18O. The vapor-phase concentrations of D and 18O have remained stable through repeated samplings. Vapor-phase 3H concentrations have generally increased with time, requiring synchronous sampling of liquid and vapor to assess equilibrium. Below 30 meters, concentrations of D and 18O in pore water become approximately equal to the composition of ground water, which is isotopically lighter than modern precipitation and has a carbon-14 (14C) concentration of about 26 percent modern carbon. These data indicate that net gradients driving fluxes of water, gas, and heat are directed upwards for undisturbed conditions at the Amargosa Desert Research Site (ADRS). Superimposed on the upward-directed flow field, tritium is migrating away from waste in response to gradients in tritium concentrations.

  8. Photo(electro)chemical oxidation of water by the persulfate ion over aqueous suspensions of strontium titanate SrTiO3 containing lanthanum chromite LaCrO3

    NARCIS (Netherlands)

    Thewissen, D.H.M.W.; Timmer, K.; Eeuwhorst‐Reinten, M.; Tinnemans, A.H.A.; Mackor, A.

    1982-01-01

    The photodecomposition of the S2O2‐ 8 ion to the SO2‐ 4 ion with concomitant oxidation of water to molecular oxygen over n‐type SrTiO3 powders mixed with LaCrO3 (mole fraction x = 0–1), using UV light (λ > 300 nm), is considerably faster than the photochemical (UV) decomposition of S2O2‐ 8 in water

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

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

    2014-01-01

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

  10. UO{sub 2} surface oxidation by mixtures of water vapor and hydrogen as a function of temperature

    Energy Technology Data Exchange (ETDEWEB)

    Espriu-Gascon, A., E-mail: alexandra.espriu@upc.edu [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Llorca, J.; Domínguez, M. [Institut de Tècniques Energètiques (INTE), Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE), Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Giménez, J.; Casas, I. [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Pablo, J. de [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, E-08243 Manresa (Spain)

    2015-12-15

    In the present work, X-Ray Photoelectron Spectroscopy (XPS) was used to study the effect of water vapor on the UO{sub 2} surface as a function of temperature. The experiments were performed in situ inside a high pressure chamber attached to the XPS instrument. UO{sub 2} samples were put in contact with either hydrogen or argon streams, saturated with water at room temperature, and the sample surface evolution was analyzed by XPS. In the case of the water vapor/argon experiments, one experiment at 350 °C was performed and, in the case of the water vapor/hydrogen experiments, the temperatures used inside the reactor were 60, 120, 200 and 350 °C. On one hand, in presence of argon, the results obtained showed that the water vapor in the argon stream oxidized 93% of the U(IV) in the sample surface. On the other hand, the degree of UO{sub 2} surface oxidation showed a different dependence on the temperature in the experiments performed in the presence of hydrogen: the maximum surface oxidation occurred at 120 °C, where 65.4% of U(IV) in the sample surface was oxidized, while at higher temperatures, the surface oxidation decreased. This observation is attributed to the increase of hydrogen reducing effect when temperature increases which prevents part of the oxidation of the UO{sub 2} surface by the water vapor. - Highlights: • UO{sub 2} surface has been oxidized by water vapor in an argon stream at 350 °C. • H{sub 2} reduced more uranium oxidation produced by water at 350 °C when compared to Ar. • In H{sub 2} presence, the uranium oxidation produced by water depends on the temperature.

  11. R-22 vapor explosions

    International Nuclear Information System (INIS)

    Anderson, R.P.; Armstrong, D.R.

    1977-01-01

    Previous experimental and theoretical studies of R-22 vapor explosions are reviewed. Results from two experimental investigations of vapor explosions in a medium scale R-22/water system are reported. Measurements following the drop of an unrestrained mass of R-22 into a water tank demonstrated the existence of two types of interaction behavior. Release of a constrained mass of R-22 beneath the surface of a water tank improved the visual resolution of the system thus allowing identification of two interaction mechansims: at low water temperatures, R-22/water contact would produce immediate violent boiling; at high water temperatures a vapor film formed around its R-22 as it was released, explosions were generated by a surface wave which initiated at a single location and propagated along the vapor film as a shock wave. A new vapor explosion model is proposed, it suggests explosions are the result of a sequence of three independent steps: an initial mixing phase, a trigger and growth phase, and a mature phase where a propagating shock wave accelerates the two liquids into a collapsing vapor layer causing a high velocity impact which finely fragments and intermixes the two liquids

  12. Modeling of the Enceladus water vapor jets for interpreting UVIS star and solar occultation observations

    Science.gov (United States)

    Portyankina, Ganna; Esposito, Larry W.; Aye, Klaus-Michael; Hansen, Candice J.

    2015-11-01

    One of the most spectacular discoveries of the Cassini mission is jets emitting from the southern pole of Saturn’s moon Enceladus. The composition of the jets is water vapor and salty ice grains with traces of organic compounds. Jets, merging into a wide plume at a distance, are observed by multiple instruments on Cassini. Recent observations of the visible dust plume by the Cassini Imaging Science Subsystem (ISS) identified as many as 98 jet sources located along “tiger stripes” [Porco et al. 2014]. There is a recent controversy on the question if some of these jets are “optical illusion” caused by geometrical overlap of continuous source eruptions along the “tiger stripes” in the field of view of ISS [Spitale et al. 2015]. The Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observed occultations of several stars and the Sun by the water vapor plume of Enceladus. During the solar occultation separate collimated gas jets were detected inside the background plume [Hansen et al., 2006 and 2011]. These observations directly provide data about water vapor column densities along the line of sight of the UVIS instrument and could help distinguish between the presence of only localized or also continuous sources. We use Monte Carlo simulations and Direct Simulation Monte Carlo (DSMC) to model the plume of Enceladus with multiple (or continuous) jet sources. The models account for molecular collisions, gravitational and Coriolis forces. The models result in the 3-D distribution of water vapor density and surface deposition patterns. Comparison between the simulation results and column densities derived from UVIS observations provide constraints on the physical characteristics of the plume and jets. The specific geometry of the UVIS observations helps to estimate the production rates and velocity distribution of the water molecules emitted by the individual jets.Hansen, C. J. et al., Science 311:1422-1425 (2006); Hansen, C. J. et al, GRL 38:L11202 (2011

  13. Effect of hygroscopic materials on water vapor permeation and dehumidification performance of poly(vinyl alcohol) membranes

    KAUST Repository

    Bui, T. D.

    2017-01-16

    In this study, two hygroscopic materials, inorganic lithium chloride (LiCl) and organic triethylene glycol (TEG) were separately added to poly(vinyl alcohol) (PVA) to form blend membranes for air dehumidification. Water vapor permeation, dehumidification performance and long-term durability of the membranes were studied systematically. Membrane hydrophilicity and water vapor sorbability increased significantly with higher the hygroscopic material contents. Water vapor permeance of the membranes increased with both added hygroscopic material and absorbed water. Water permeation energy varied from positive to negative with higher hygroscopic content. This observation is attributed to a lower diffusion energy and a relatively constant sorption energy when hygroscopic content increases. Comparatively, PVA/TEG has less corrosive problems and is more environmentally friendly than PVA/LiCl. A membrane with PVA/TEG is observed to be highly durable and is suitable for dehumidification applications.

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

    Science.gov (United States)

    Rall, Jonathan A. R.

    1994-01-01

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

  15. LASE measurements of water vapor and aerosol profiles during the Plains Elevated Convection at Night (PECAN) field experiment

    Science.gov (United States)

    Nehrir, A. R.; Ferrare, R. A.; Kooi, S. A.; Butler, C. F.; Notari, A.; Hair, J. W.; Collins, J. E., Jr.; Ismail, S.

    2015-12-01

    The Lidar Atmospheric Sensing Experiment (LASE) system was deployed on the NASA DC-8 aircraft during the Plains Elevated Convection At Night (PECAN) field experiment, which was conducted during June-July 2015 over the central and southern plains. LASE is an active remote sensor that employs the differential absorption lidar (DIAL) technique to measure range resolved profiles of water vapor and aerosols above and below the aircraft. The DC-8 conducted nine local science flights from June 30- July 14 where LASE sampled water vapor and aerosol fields in support of the PECAN primary science objectives relating to better understanding nocturnal Mesoscale Convective Systems (MCSs), Convective Initiation (CI), the Low Level Jet (LLJ), bores, and to compare different airborne and ground based measurements. LASE observed large spatial and temporal variability in water vapor and aerosol distributions in advance of nocturnal MCSs, across bores resulting from MCS outflow boundaries, and across the LLJ associated with the development of MCSs and CI. An overview of the LASE data collected during the PECAN field experiment will be presented where emphasis will be placed on variability of water vapor profiles in the vicinity of severe storms and intense convection in the central and southern plains. Preliminary comparisons show good agreement between coincident LASE and radiosonde water vapor profiles. In addition, an advanced water vapor DIAL system being developed at NASA Langley will be discussed.

  16. Worldwide data sets constrain the water vapor uptake coefficient in cloud formation.

    Science.gov (United States)

    Raatikainen, Tomi; Nenes, Athanasios; Seinfeld, John H; Morales, Ricardo; Moore, Richard H; Lathem, Terry L; Lance, Sara; Padró, Luz T; Lin, Jack J; Cerully, Kate M; Bougiatioti, Aikaterini; Cozic, Julie; Ruehl, Christopher R; Chuang, Patrick Y; Anderson, Bruce E; Flagan, Richard C; Jonsson, Haflidi; Mihalopoulos, Nikos; Smith, James N

    2013-03-05

    Cloud droplet formation depends on the condensation of water vapor on ambient aerosols, the rate of which is strongly affected by the kinetics of water uptake as expressed by the condensation (or mass accommodation) coefficient, αc. Estimates of αc for droplet growth from activation of ambient particles vary considerably and represent a critical source of uncertainty in estimates of global cloud droplet distributions and the aerosol indirect forcing of climate. We present an analysis of 10 globally relevant data sets of cloud condensation nuclei to constrain the value of αc for ambient aerosol. We find that rapid activation kinetics (αc > 0.1) is uniformly prevalent. This finding resolves a long-standing issue in cloud physics, as the uncertainty in water vapor accommodation on droplets is considerably less than previously thought.

  17. Validation of Atmospheric Water Vapor Derived from Ship-Borne GPS Measurements in the Chinese Bohai Sea

    Directory of Open Access Journals (Sweden)

    Shi-Jie Fan

    2016-04-01

    Full Text Available Atmospheric water vapor (AWV was investigated for the first time in the Chinese Bohai Sea using a Global Positioning System (GPS receiver aboard a lightweight (300-ton ship. An experiment was conducted to retrieve the AWV using the state-of-the-art GPS precise point positioning (PPP technique. The effects of atmospheric weighted mean temperature model and zenith wet delay constraint on GPS AWV estimates were discussed in the PPP estimation system. The GPS-derived precipitable water vapor (PWV and slant-path water vapor (SWV were assessed by comparing with those derived from the Fifth Generation NCAR/Penn State Mesoscale Model (MM5. The results showed the PWV and SWV differences between those derived from both GPS and MM5 are 1.5 mm root mean square (RMS with a bias of 0.2 and 3.9 mm RMS with a bias of -0.7 mm respectively. These good agreements indicate that the GPS-derived AWV in dynamic environments has a comparable accuracy with that of the MM5 model. This suggests that high accuracy and high spatio-temporal resolution humidity fields can be obtained using GPS in the Chinese Bohai Sea, which offers significant potential for meteorological applications and climate studies in this region.

  18. Preconcentration and in-situ photoreduction of trace selenium using TiO2 nanoparticles, followed by its determination by slurry photochemical vapor generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Yang, Wulin; Wu, Li; Zhu, Xiaofan; Gao, Ying; Hou, Xiandeng; Zheng, Chengbin

    2014-01-01

    We have developed a method for the determination of trace levels of total selenium in water samples. It integrates preconcentration, in-situ photoreduction and slurry photochemical vapor generation using TiO 2 nanoparticles, and the determination of total selenium by AFS. The Se(IV) and Se(VI) species were adsorbed on a slurry of TiO 2 nanoparticles which then were exposed to UV irradiation in the presence of formic acid to form volatile selenium species. The detection limits were improved 17-fold compared to hydride generation and 56-fold compared to photochemical vapor generation, both without any preconcentration. No significant difference was found in the limits of detection (LODs) for Se(IV) and Se(VI). The LOD is as low as 0.8 ng L −1 , the precision is better than 4.5 % (at a level of 0.1 μg L −1 of selenium). The method gave good recoveries when applied to the determination of total selenium in a certified tissue reference material (DORM-3) and in spiked drinking water and wastewater samples containing high concentrations of transition and noble metal ions. It also excels by very low LODs, a significant enhancement of sample throughput, reduced reagent consumption and sample loss, and minimal interference by transition and noble metal ions. (author)

  19. Spectral control of an alexandrite laser for an airborne water-vapor differential absorption lidar system

    Science.gov (United States)

    Ponsardin, Patrick; Grossmann, Benoist E.; Browell, Edward V.

    1994-01-01

    A narrow-linewidth pulsed alexandrite laser has been greatly modified for improved spectral stability in an aircraft environment, and its operation has been evaluated in the laboratory for making water-vapor differential absorption lidar measurements. An alignment technique is described to achieve the optimum free spectral range ratio for the two etalons inserted in the alexandrite laser cavity, and the sensitivity of this ratio is analyzed. This technique drastically decreases the occurrence of mode hopping, which is commonly observed in a tunable, two-intracavity-etalon laser system. High spectral purity (greater than 99.85%) at 730 nm is demonstrated by the use of a water-vapor absorption line as a notch filter. The effective cross sections of 760-nm oxygen and 730-nm water-vapor absorption lines are measured at different pressures by using this laser, which has a finite linewidth of 0.02 cm(exp -1) (FWHM). It is found that for water-vapor absorption linewidths greater than 0.04 cm(exp -1) (HWHM), or for altitudes below 10 km, the laser line can be considered monochromatic because the measured effective absorption cross section is within 1% of the calculated monochromatic cross section. An analysis of the environmental sensitivity of the two intracavity etalons is presented, and a closed-loop computer control for active stabilization of the two intracavity etalons in the alexandrite laser is described. Using a water-vapor absorption line as a wavelength reference, we measure a long-term frequency drift (approximately 1.5 h) of less than 0.7 pm in the laboratory.

  20. Preparation of Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} catalyst and its catalytic properties for selective reduction of NO

    Energy Technology Data Exchange (ETDEWEB)

    Xi-kun Guo; Ping-ping Xie; Shu-dong Lin [Shantou University, Shantou (China). Department of Chemistry

    2008-12-15

    An La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} composite support was prepared by co-precipitation with the mixed aqueous solution of La(NO{sub 3}{sub 3}, Al(NO{sub 3){sub 3}, and ZrOCl{sub 2} dropping into the precipitant of (NH{sub 4})2CO{sub 3} aqueous solution. The Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} catalyst was prepared by the impregnation of La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} with active component Cu{sup 2+} aqueous solution. The effects of the catalyst on the selective catalytic reduction of NO with propylene in excess oxygen were investigated. The relationships between the preparation method, structure and properties of the Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} catalyst were also explored by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), surface area measurements (BET), pyridine absorption infrared spectrum (Py-IR), thermal gravimetry (TG), and temperature-programmed reduction (TPR). The results indicate that the support {gamma}-Al{sub 2}O{sub 3} prepared by Al(NO{sub 3})3 dropping into (NH{sub 4}{sub 2} CO{sub 3} can remarkably enlarge the surface area; the addition of La{sub 2}O{sub 3} contributes mainly to the enhancement of the thermal stability; and the introduction of ZrO{sub 2} can increase the amount of Lewis and Broenstead acid. Consequently, the catalyst Cu/La{sub 2}O{sub 3}-ZrO{sub 2}-Al{sub 2}O{sub 3} has excellent activity for the selective reduction of NO with propylene in excess oxygen. NO conversion is up to 88.9% at 300{sup o}C and 81.9% even at the presence of 10% volume fraction of water vapor. 15 refs., 8 figs., 1 tab.

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

    International Nuclear Information System (INIS)

    Choi, Bum Ho; Lee, Jong Ho

    2014-01-01

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

  2. Characterization of Pb(Zr, Ti)O3 thin films fabricated by plasma enhanced chemical vapor deposition on Ir-based electrodes

    International Nuclear Information System (INIS)

    Lee, Hee-Chul; Lee, Won-Jong

    2002-01-01

    Structural and electrical characteristics of Pb(Zr, Ti)O 3 (PZT) ferroelectric thin films deposited on various Ir-based electrodes (Ir, IrO 2 , and Pt/IrO 2 ) using electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. On the Ir electrode, stoichiometric PZT films with pure perovskite phase could be obtained over a very wide range of processing conditions. However, PZT films prepared on the IrO 2 electrode contain a large amount of PbO x phases and exhibited high Pb-excess composition. The deposition characteristics were dependent on the behavior of PbO molecules on the electrode surface. The PZT thin film capacitors prepared on the Ir bottom electrode showed different electrical properties depending on top electrode materials. The PZT capacitors with Ir, IrO 2 , and Pt top electrodes showed good leakage current characteristics, whereas those with the Ru top electrode showed a very high leakage current density. The PZT capacitor exhibited the best fatigue endurance with an IrO 2 top electrode. An Ir top electrode provided better fatigue endurance than a Pt top electrode. The PZT capacitor with an Ir-based electrode is thought to be attractive for the application to ferroelectric random access memory devices because of its wide processing window for a high-quality ferroelectric film and good polarization, fatigue, and leakage current characteristics

  3. Thermally activated 3D to 2D structural transformation of [Ni2(en)2(H2O)6(pyr)]·4H2O flexible coordination polymer

    International Nuclear Information System (INIS)

    Begović, Nebojša N.; Blagojević, Vladimir A.; Ostojić, Sanja B.; Radulović, Aleksandra M.; Poleti, Dejan; Minić, Dragica M.

    2015-01-01

    Thermally activated 3D to 2D structural transformation of the binuclear [Ni 2 (en) 2 (H 2 O) 6 (pyr)]·4H 2 O complex was investigated using a combination of theoretical and experimental methods. Step-wise thermal degradation (dehydration followed by release of ethylene diamine) results in two layered flexible coordination polymer structures. Dehydration process around 365 K results in a conjugated 2D structure with weak interlayer connectivity. It was shown to be a reversible 3D to 2D framework transformation by a guest molecule, and rehydration of the dehydration product occurs at room temperature in saturated water vapor. Rehydrated complex exhibits lower dehydration temperature, due to decreased average crystalline size, with higher surface area resulting in easier release and diffusion of water during dehydration. Thermal degradation of dehydration around 570 K, results in loss of ethylene diamine, producing a related 2D layered polymer structure, without interconnectivity between individual polymer layers. - Highlights: • Reversible 3D to 2D framework topochemical transformation on dehydration around 365 K. • Resulting polymer exhibits 2D layered structure with weak interlayer connectivity. • Dehydration is fully reversible in saturated water vapor at room temperature. • Further degradation around 570 K yields 2D polymer without interlayer connectivity. • 2D polymer exhibits conjugated electronic system

  4. Vapor-Liquid Equilibrium of Methane with Water and Methanol. Measurements and Modeling

    DEFF Research Database (Denmark)

    Frost, Michael Grynnerup; Karakatsani, Eirini; von Solms, Nicolas

    2014-01-01

    that rely on phase equilibrium data for optimization. The objective of this work is to provide experimental data for hydrocarbon systems with polar chemicals such as alcohols, glycols, and water. New vapor-liquid equilibrium data are reported for methane + water, methane + methanol, and methane + methanol...

  5. Evidence of water vapor in excess of saturation in the atmosphere of Mars.

    Science.gov (United States)

    Maltagliati, L; Montmessin, F; Fedorova, A; Korablev, O; Forget, F; Bertaux, J-L

    2011-09-30

    The vertical distribution of water vapor is key to the study of Mars' hydrological cycle. To date, it has been explored mainly through global climate models because of a lack of direct measurements. However, these models assume the absence of supersaturation in the atmosphere of Mars. Here, we report observations made using the SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) instrument onboard Mars Express that provide evidence of the frequent presence of water vapor in excess of saturation, by an amount far surpassing that encountered in Earth's atmosphere. This result contradicts the widespread assumption that atmospheric water on Mars cannot exist in a supersaturated state, directly affecting our long-term representation of water transport, accumulation, escape, and chemistry on a global scale.

  6. Interannual Variability in the Meridional Transport of Water Vapor

    Science.gov (United States)

    Cohen, Judah L.; Salstein, David A.; Rosen, Richard D.

    2000-01-01

    The zonal-mean meridional transport of water vapor across the globe is evaluated using the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis for 1948-97. The shape of the meridional profile of the climatological mean transport closely resembles that of previous mean climate descriptions, but values tend to be notably larger than in climatologies derived from radiosonde-only-based analyses. The unprecedented length of the NCEP-NCAR dataset invites a focus on interannual variations in the zonal-mean moisture transport, and these results for northern winter are highlighted here. Although interannual variability in the transport is typically small at most latitudes, a significant ENSO signal is present, marked by a strengthening of water vapor transports over much of the winter hemisphere during warm events. Because of an increase in tropical sea surface temperatures and in the frequency of warm events relative to cold events in the latter half of the 50-yr record, this interannual signal projects onto an overall trend toward enhanced meridional moisture transports in the global hydrological cycle.

  7. Effective preparation of magnetic superhydrophobic Fe3O4/PU sponge for oil-water separation

    Science.gov (United States)

    Li, Zeng-Tian; Lin, Bo; Jiang, Li-Wang; Lin, En-Chao; Chen, Jian; Zhang, Shi-Jie; Tang, Yi-Wen; He, Fu-An; Li, De-Hao

    2018-01-01

    Fe3O4 nanoparticles were modified by tetraethoxysilane and different amounts of trimethoxy (1H,1H,2H,2H-heptadecafluorodecyl) silane in sequence to obtain the magnetic nanoparticles with low surface energy, which could be used to construct the superhydrophobic surfaces for PU sponge, cotton fabric, and filter paper by a simple drop-coating method. Particularly, all the resultant Fe3O4/PU sponges containing different fluoroalkylsilane-modified Fe3O4 nanoparticles possessed both high water repellency with contact angle in the range of 150.2-154.7° and good oil affinity, which could not only effectively remove oil from water followed by convenient magnetic recovery but also easily realize the oil-water separation as a filter only driven by gravity. The Fe3O4/PU sponges showed high absorption capability of peanut oil, pump oil, and silicone oil with the maximum absorptive capacities of 40.3, 39.3, and 46.3 g/g, respectively. Such novel sponges might be a potential candidate for oil-water separation as well as oil absorption and transportation accompanied by the advantages of simple process, remote control by magnetic field, and low energy consumption.

  8. Auxiliary Electrodes for Chromium Vapor Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Fergus, Jeffrey; Shahzad, Moaiz; Britt, Tommy

    2018-05-15

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

  9. Vapor diffusion synthesis of rugby-shaped CoFe2O4/graphene composites as absorbing materials

    International Nuclear Information System (INIS)

    Zhang, Shenli; Jiao, Qingze; Hu, Ju; Li, Jingjing; Zhao, Yun; Li, Hansheng; Wu, Qin

    2015-01-01

    Graphical abstract: CoFe 2 O 4 rugbies/graphene composites were prepared using a vapor diffusion method followed by calcination. As-synthesized rugby-like CoFe 2 O 4 particles were distributed on the graphene sheet. PVP played a key role for the formation of rugby-shaped morphology of CoFe 2 O 4 particles. A minimum reflection loss of −39.0 dB was observed at 10.9 GHz for the CoFe 2 O 4 rugbies/graphene composites with a thickness of 2 mm, and the effective absorption bandwidth was 4.7 GHz. The CoFe 2 O 4 rugbies/graphene composites exhibited better microwave absorbing performance than that of the CoFe 2 O 4 nanoparticles/graphene composites prepared without PVP. - Highlights: • CoFe 2 O 4 rugbies/graphene hybrids were synthesized using a vapor diffusion method. • PVP played a key role for the formation of CoFe 2 O 4 rugbies. • CoFe 2 O 4 rugbies/graphene composites showed excellent microwave absorbing property. - Abstract: Rugby-shaped CoFe 2 O 4 /graphene composites were synthesized using a vapor diffusion method in combination with calcination. The morphologies and structures of the products were characterized by field emission scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The magnetic and electromagnetic parameters were measured using a vibrating sample magnetometer and a vector network analyzer, respectively. Results show that rugby-shaped CoFe 2 O 4 particles are distributed on graphene sheets. A minimum reflection loss (RL) of −39.0 dB is observed at 10.9 GHz for the sample with a thickness of 2.0 mm, and the effective absorption frequency (RL < −10 dB) ranges from 9.6 to 14.3 GHz, indicating the excellent microwave absorption performance of the products. The absorbing performance of the CoFe 2 O 4 rugbies/graphene composites is better than that of the CoFe 2 O 4 nanoparticles/graphene composites

  10. Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow

    Directory of Open Access Journals (Sweden)

    W. J. Massman

    2008-10-01

    Full Text Available Recent studies with closed-path eddy covariance (EC systems have indicated that the attenuation of fluctuations of water vapor concentration is dependent upon ambient relative humidity, presumably due to sorption/desorption of water molecules at the interior surface of the tube. Previous studies of EC-related tube attenuation effects have either not considered this issue at all or have only examined it superficially. Nonetheless, the attenuation of water vapor fluctuations is clearly much greater than might be expected from a passive tracer in turbulent tube flow. This study reexamines the turbulent tube flow issue for both passive and sorbing tracers with the intent of developing a physically-based semi-empirical model that describes the attenuation associated with water vapor fluctuations. Toward this end, we develop a new model of tube flow dynamics (radial profiles of the turbulent diffusivity and tube airstream velocity. We compare our new passive-tracer formulation with previous formulations in a systematic and unified way in order to assess how sensitive the passive-tracer results depend on fundamental modeling assumptions. We extend the passive tracer model to the vapor sorption/desorption case by formulating the model's wall boundary condition in terms of a physically-based semi-empirical model of the sorption/desorption vapor fluxes. Finally we synthesize all modeling and observational results into a single analytical expression that captures the effects of the mean ambient humidity and tube flow (Reynolds number on tube attenuation.

  11. VESPA-22: a ground-based microwave spectrometer for long-term measurements of polar stratospheric water vapor

    Science.gov (United States)

    Mevi, Gabriele; Muscari, Giovanni; Bertagnolio, Pietro Paolo; Fiorucci, Irene; Pace, Giandomenico

    2018-02-01

    The new ground-based 22 GHz spectrometer, VESPA-22 (water Vapor Emission Spectrometer for Polar Atmosphere at 22 GHz) measures the 22.23 GHz water vapor emission line with a bandwidth of 500 MHz and a frequency resolution of 31 kHz. The integration time for a measurement ranges from 6 to 24 h, depending on season and weather conditions. Water vapor spectra are collected using the beam-switching technique. VESPA-22 is designed to operate automatically with little maintenance; it employs an uncooled front-end characterized by a receiver temperature of about 180 K and its quasi-optical system presents a full width at half maximum of 3.5°. Every 30 min VESPA-22 measures also the sky opacity using the tipping curve technique. The instrument calibration is performed automatically by a noise diode; the emission temperature of this element is estimated twice an hour by observing alternatively a black body at ambient temperature and the sky at an elevation of 60°. The retrieved profiles obtained inverting 24 h integration spectra present a sensitivity larger than 0.8 from about 25 to 75 km of altitude during winter and from about 30 to 65 km during summer, a vertical resolution from about 12 to 23 km (depending on altitude), and an overall 1σ uncertainty lower than 7 % up to 60 km altitude and rapidly increasing to 20 % at 75 km. In July 2016, VESPA-22 was installed at the Thule High Arctic Atmospheric Observatory located at Thule Air Base (76.5° N, 68.8° W), Greenland, and it has been operating almost continuously since then. The VESPA-22 water vapor mixing ratio vertical profiles discussed in this work are obtained from 24 h averaged spectra and are compared with version 4.2 of concurrent Aura/Microwave Limb Sounder (MLS) water vapor vertical profiles. In the sensitivity range of VESPA-22 retrievals, the intercomparison from July 2016 to July 2017 between VESPA-22 dataset and Aura/MLS dataset convolved with VESPA-22 averaging kernels shows an average difference

  12. Rapid increases in permeability and porosity of bentonite-sand mixtures due to alteration by water vapor

    International Nuclear Information System (INIS)

    Couture, R.A.

    1984-01-01

    Packed columns of canister packing material containing 25% bentonite and 75% quartz or basalt sand, were exposed to water vapor at temperatures up t 260 0 C. The permeabilities of the columns were subsequently measured after complete saturation with liquid water in a pressurized system. Exposure to water vapor caused irreversible increases in permeability by factors of up to 10 5 . After saturation with liquid water, the permeability was nearly independent of temperature. The increases in permeability were due to a large decrease in the ability of the bentonite to swell in water. Calculations suggest that swelling of bentonite altered at 250 0 C was not sufficient to fill the pore spaces. If the pore spaces are filled, the mixture will form an effective barrier against flow, diffusion, and transport of colloids. The results suggest that if bentonite-based canister packing material is exposed even briefly to water vapor at high temperatures in a high-level nuclear waste repository, its performance will be seriously impaired. The problem is less severe if the proportion of bentonite is high and the material is highly compacted. Previous results show significant degradation of bentonite by water vapor at temperatures as low as 150 0 C. This suggests that in some repositories, backfill in tunnels and drifts may also be affected. 9 references, 5 figures, 1 table

  13. Improvement of Oil-Vapor Treatment Facility for Wolsong Unit 3,4

    International Nuclear Information System (INIS)

    Kim, Jeong Guk; Kwon, S. W.; Lee, H. S.

    2009-11-01

    With the purpose to minimize an oil-vapor discharge to the atmosphere and to be an environmentally friendly nuclear power plant by an improvement of mist eliminator for turbine lubricant system at Wolsong Nuclear Power Plant Unit 3,4, this project - project name : Improvement of Oil-vapor Treatment Facility for Wolsong Unit 3,4 - was conducted for six months (from Apr. 15, 2009 to Oct. 14, 2009). This Project contains Oil-vapor Source and Environmental Regulation, Analysis on the Present Oil-vapor Treatment Facility, Improvement of Oil-vapor Treatment Facility, Test Facility Design, Fabrication, Installation, Test Operation, Evaluation of the Facility

  14. Aircraft profile measurements of 18O/16O and D/H isotope ratios of cloud condensate and water vapor constrain precipitation efficiency and entrainment rates in tropical clouds

    Science.gov (United States)

    Noone, D. C.; Raudzens Bailey, A.; Toohey, D. W.; Twohy, C. H.; Heymsfield, A.; Rella, C.; Van Pelt, A. D.

    2011-12-01

    Convective clouds play a significant role in the moisture and heat balance of the tropics. The dynamics of organized and isolated convection are a function of the background thermodynamic profile and wind shear, buoyancy sources near the surface and the latent heating inside convective updrafts. The stable oxygen and hydrogen isotope ratios in water vapor and condensate can be used to identify dominant moisture exchanges and aspects of the cloud microphysics that are otherwise difficult to observe. Both the precipitation efficiency and the dilution of cloud updrafts by entrainment can be estimated since the isotopic composition outside the plume is distinct from inside. Measurements of the 18O/16O and D/H isotope ratios were made in July 2011 on 13 research flights of the NCAR C130 aircraft during the ICE-T (Ice in Clouds Experiment - Tropical) field campaign near St Croix. Measurements were made using an instrument based on the Picarro Wave-Length Scanning Cavity Ring Down platform that includes a number of optical, hardware and software modifications to allow measurements to be made at 5 Hz for deployment on aircraft. The measurement system was optimized to make precise measurements of the isotope ratio of liquid and ice cloud condensate by coupling the gas analyzer to the NCAR Counter flow Virtual Impactor inlet. The inlet system provides a particle enhancement while rejecting vapor. Sample air is vigorously heated before flowing into the gas phase analyzer. We present statistics that demonstrate the performance and calibration of the instrument. Measured profiles show that environmental air exhibits significant layering showing controls from boundary layer processes, large scale horizontal advection and regional subsidence. Condensate in clouds is consistent with generally low precipitation efficiency, although there is significant variability in the isotope ratios suggesting heterogeneity within plumes and the stochastic nature of detrainment processes

  15. Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

    Science.gov (United States)

    Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.; hide

    2012-01-01

    Here we report the measurement of water vapor in Titan's stratosphere using the Cassini Composite Infrared Spectrometer (CIRS). CIRS senses water emissions in the far infrared spectral region near 50 micron, which we have modeled using two independent radiative transfer codes. From the analysis of nadir spectra we have derived a mixing ratio of 0.14 +/- 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7 +/- 1.3 1014 molecules/cm2. In the latitude range 80S to 30N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 +/- 0.04 ppb at an altitude of 115 km and 0.45 +/- 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. We have also fitted our data using scaling factors of 0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan's lower stratosphere.

  16. WO3 nanoflakes decorated with CuO clusters for enhanced photoelectrochemical water splitting

    Directory of Open Access Journals (Sweden)

    Chongwu Wang

    2018-04-01

    Full Text Available The low quantum efficiency arising from poor charges transfer and insufficient light absorption is one of the critical challenges toward achieving highly efficient water splitting in photoelectrochemical cells. Three dimensions (3D structures and heterojunctions have received intensive research interests recent years due to their excellent ability to separate photo-generated charges as well as the enhanced light harvesting property. Herein, 3D CuO/WO3 structure was fabricated through a facile solvothermal method followed by chemical bath deposition. The loading of CuO clusters on WO3 nanoflake arrays results in a much improved photocurrent density compared with that of pristine WO3 nanoflake arrays, which reaches 1.8 mA/cm2 at 1.23 V vs. the reversible hydrogen electrode. The electrochemical impedance spectroscopy measurement demonstrates that the improved performance of CuO/WO3 electrode is attributed to the accelerated charge transfer kinetics as a result of the desirable band alignment in CuO/WO3 heterojunction. This work demonstrates a facile strategy to construct superior WO3 electrode, which will ultimately allow for efficient storage of solar energy into hydrogen. Keywords: Photoelectrochemistry, Water splitting, Tungsten trioxide photoanode, CuO clusters, Heterojunction

  17. D2O, Computation of Thermodynamic and Transport Properties of Heavy Water

    International Nuclear Information System (INIS)

    Durmayaz, Ahmet

    2000-01-01

    1 - Description of program or function: A computer program for the fast computation of the thermodynamic and transport properties of heavy water (D 2 O) at saturation, in subcooled liquid and superheated vapor states. Specific volume (or density), specific enthalpy, specific entropy, constant-pressure specific heat and temperature at saturation are calculated by a number of piecewise continuous approximation functions of (and their derivatives are calculated with respect to) pressure whereas pressure at saturation is calculated by a piecewise continuous approximation function of temperature for heavy water. Density in subcooled liquid state, specific volume in super-heated vapor state, specific enthalpy, specific entropy and constant-pressure specific heat in both of these states are calculated by some piecewise continuous approximation functions of pressure and temperature for heavy water. The correlations used in the calculation of these thermodynamic properties of heavy water were derived by fitting some appropriate curves to the data given in the steam tables by Hill et al (1981). The whole set of correlations and the approximation method used in their derivation are presented by Durmayaz (1997). Dynamic viscosity and thermal conductivity for heavy water are calculated as functions of temperature and density with the correlations given by Hill et al (1981), by Matsunaga and Nagashima (1983) and by Kestin et al (1984). Surface tension for heavy water is calculated as a function of temperature with the correlation given by Crabtree and Siman-Tov (1993). 2 - Methods: A group of pressure-enthalpy (P-h) pairs can be given in an input data file or assigned in the main program without knowing the state in which fluid takes place. In this case, first, the enthalpies at saturation corresponding to the given pressure are computed. Second, the state is determined by comparing the given enthalpy to the saturation enthalpies. Then, the properties are computed. Program D 2 O

  18. The simulation of stratospheric water vapor in the NH summer monsoon regions in a suite of WACCM models

    Science.gov (United States)

    Wang, X.; Wu, Y.; Huang, Y.; Tilmes, S.

    2016-12-01

    Water vapor maxima are found in the upper troposphere lower stratosphere (UTLS) over Asian and North America monsoon regions during Northern Hemisphere (NH) summer months. High concentrations of stratospheric water vapor are associated with the upper-level anticyclonic circulation and they play an important role in the radiative forcing for the climate system. However, discrepancies in the simulation of stratospheric water vapor are found among different models. In this study, we use both observational data: Aura Microwave Limb Sounder satellite observations (MLS), the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) and chemistry climate model outputs: different configurations of the Whole Atmosphere Community Climate Model (WACCM), including standard configuration of WACCM, WACCM L110, specified chemistry (SC) WACCM and specified dynamics (SD) WACCM. We find that WACCM L110 with finer vertical resolution better simulates the stratospheric water vapor maxima over the summer monsoon regions. To better understand the mechanism, we examine the simulated temperature at around 100 hPa since 100 hPa is known to act as a dehydration mechanism, i.e. the warmer the temperature, the wetter the stratospheric water vapor. We find that both WACCM L110 and SD-WACCM better simulate the temperature at 100 hPa as compared to that of MERRA2. This suggests that improving model vertical resolution and dynamical processes in the UTLS is crucial in simulating the stratospheric water vapor concentrations.

  19. An integrated optic ethanol vapor sensor based on a silicon-on-insulator microring resonator coated with a porous ZnO film.

    Science.gov (United States)

    Yebo, Nebiyu A; Lommens, Petra; Hens, Zeger; Baets, Roel

    2010-05-24

    Optical structures fabricated on silicon-on-insulator technology provide a convenient platform for the implementation of highly compact, versatile and low cost devices. In this work, we demonstrate the promise of this technology for integrated low power and low cost optical gas sensing. A room temperature ethanol vapor sensor is demonstrated using a ZnO nanoparticle film as a coating on an SOI micro-ring resonator of 5 microm in radius. The local coating on the ring resonators is prepared from colloidal suspensions of ZnO nanoparticles of around 3 nm diameter. The porous nature of the coating provides a large surface area for gas adsorption. The ZnO refractive index change upon vapor adsorption shifts the microring resonance through evanescent field interaction. Ethanol vapor concentrations down to 100 ppm are detected with this sensing configuration and a detection limit below 25 ppm is estimated.

  20. Water vapor weathering of Taurus-Littrow orange soil - A pore-structure analysis

    Science.gov (United States)

    Cadenhead, D. A.; Mikhail, R. S.

    1975-01-01

    A pore-volume analysis was performed on water vapor adsorption data previously obtained on a fresh sample of Taurus-Littrow orange soil, and the analysis was repeated on the same sample after its exposure to moist air for a period of approximately six months. The results indicate that exposure of an outgassed sample to high relative pressures of water vapor can result in the formation of substantial micropore structure, the precise amount being dependent on the sample pretreatment, particularly the outgassing temperature. Micropore formation is explained in terms of water penetration into surface defects. In contrast, long-term exposure to moist air at low relative pressures appears to reverse the process with the elimination of micropores and enlargement of mesopores possibly through surface diffusion of metastable adsorbent material. The results are considered with reference to the storage of lunar samples.

  1. Insertion of water into rare earth oxocuprates (Ln)Ba 2Cu 3O 7-δ

    Science.gov (United States)

    Günther, Wulf; Schöllhorn, Robert

    1996-02-01

    The solid state reaction of LnBa 2Cu 3O 7-δ bulk material with water vapour corresponds to a quantitative topotactic reaction of the solid with H 2O to a maximum stoichiometry of LnBa 2Cu 3O 7-δ(H 2O) 1. The reaction proceeds in a temperature window which depends upon the oxygen content (δ) of the starting phase and is correlated with a structural transition via intermediate states. Although the integral copper oxidation state is not affected by the water intercalation, electronic and transport properties are strongly influenced. The insertion of water into these defect perovskites has to be described as a topotactic acid/base process.

  2. Observing Tropospheric Water Vapor by Radio Occultation using the Global Positioning System

    Science.gov (United States)

    Kursinski, E. R.; Hajj, G. A.; Hardy, K. R.; Romans, L. J.; Schofield, J. T.

    1995-01-01

    Given the importance of water vapor to weather, climate and hydrology, global humidity observations from satellites are critical. At low latitudes, radio occultation observations of Earth's atmosphere using the Global Positioning System (GPS) satellites allow water vapor profiles to be retrieved with accuracies of 10 to 20% below 6 to 7 km altitude and approx. 5% or better within the boundary layer. GPS observations provide a unique combination of accuracy, vertical resolution (less than or equal to 1 km) and insensitivity to cloud and aerosol particles that is well suited to observations of the lower troposphere. These characteristics combined with the inherent stability of radio occultation observations make it an excellent candidate for the measurement of long term trends.

  3. Development of Raman-Mie lidar system for aerosol and water vapor profiling

    Science.gov (United States)

    Deng, Qian; Wang, Zhenzhu; Xu, Jiwei; Tan, Min; Wu, Decheng; Xie, Chenbo; Liu, Dong; Wang, Yingjian

    2018-03-01

    Aerosol and water vapor are two important atmospheric parameters. The accurate quantification of diurnal variation of these parameters are very useful for environment assessment and climate change studies. A moveable, compact and unattended lidar system based on modular design is developed for aerosol extinction coefficients and water vapor mixing ratios measurements. In the southern suburbs of Beijing, the continuous observation was carried out by this lidar since the middle of the year of 2017. The lidar equipment is presented and the case study is also described in this paper. The observational results show that the lidar kept a very good status from the long-time continuous measurements which is suitable for networking especially in meteorological research field.

  4. Validation of MODIS integrated water vapor product against reference GPS data at the Iberian Peninsula

    Science.gov (United States)

    Vaquero-Martínez, Javier; Antón, Manuel; Ortiz de Galisteo, José Pablo; Cachorro, Victoria E.; Costa, Maria João; Román, Roberto; Bennouna, Yasmine S.

    2017-12-01

    In this work, the water vapor product from MODIS (MODerate-resolution Imaging Spectroradiometer) instrument, on-board Aqua and Terra satellites, is compared against GPS water vapor data from 21 stations in the Iberian Peninsula as reference. GPS water vapor data is obtained from ground-based receiver stations which measure the delay caused by water vapor in the GPS microwave signals. The study period extends from 2007 until 2012. Regression analysis in every GPS station show that MODIS overestimates low integrated water vapor (IWV) data and tends to underestimate high IWV data. R2 shows a fair agreement, between 0.38 and 0.71. Inter-quartile range (IQR) in every station is around 30-45%. The dependence on several parameters was also analyzed. IWV dependence showed that low IWV are highly overestimated by MODIS, with high IQR (low precision), sharply decreasing as IWV increases. Regarding dependence on solar zenith angle (SZA), performance of MODIS IWV data decreases between 50° and 90°, while night-time MODIS data (infrared) are quite stable. The seasonal cycles of IWV and SZA cause a seasonal dependence on MODIS performance. In summer and winter, MODIS IWV tends to overestimate the reference IWV value, while in spring and autumn the tendency is to underestimate. Low IWV from coastal stations is highly overestimated (∼60%) and quite imprecise (IQR around 60%). On the contrary, high IWV data show very little dependence along seasons. Cloud-fraction (CF) dependence was also studied, showing that clouds display a negligible impact on IWV over/underestimation. However, IQR increases with CF, except in night-time satellite values, which are quite stable.

  5. A study of Water flooding modeling for DMFC at cathode channel

    International Nuclear Information System (INIS)

    Dong, Sang Keun; Yoo, Ki Soo; Lee, Dae Keun; Chung, Myung Kyoon

    2007-01-01

    The present paper addresses the water flooding model validation in cathode channel for DMFC. Water flooding not only reduces DMFC stack performance but also causes O 2 starve that damages membrane at cathode channel. Although the water flooding problem is critical in operating DMFC, it has not been resolved yet since the effect of temperature, H 2 O vapor and liquid partial pressure effects on the H 2 O vapor saturation is very complex. Therefore, the operating feasible range in the dynamic control of DMFC is inevitably narrow. In order to be able to dynamically control the DMFC to prevent water flooding problem at cathode channel, 3D numerical model was validated by comparison with experimental result. We performed numerical simulation for a wide range of Vcell - current density for 1 layer-1 cell DMFC and the results were compared with experimental data. It was found that the 3D simulation model for the DMFC can be used to accurately predict the water flooding at cathode channel

  6. Electrochemical vapor generation of selenium species after online photolysis and reduction by UV-irradiation under nano TiO{sub 2} photocatalysis and its application to selenium speciation by HPLC coupled with atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jing; Wang, Qiuquan; Huang, Benli [Xiamen University (China). Department of Chemistry; MOE Key Laboratory of Analytical Sciences, Xiamen (China)

    2005-01-01

    An online UV photolysis and UV/TiO{sub 2} photocatalysis reduction device (UV-UV/TiO{sub 2} PCRD) and an electrochemical vapor generation (ECVG) cell have been used for the first time as an interface between high-performance liquid chromatography (HPLC) and atomic fluorescence spectrometry (AFS) for selenium speciation. The newly designed ECVG cell of approximately 115 {mu}L dead volume consists of a carbon fiber cathode and a platinum loop anode; the atomic hydrogen generated on the cathode was used to reduce selenium to vapor species for AFS determination. The noise was greatly reduced compared with that obtained by use of the UV-UV/TiO{sub 2} PCRD-KBH{sub 4}-acid interface. The detection limits obtained for seleno-DL-cystine (SeCys), selenite (Se{sup IV}), seleno-DL-methionine (SeMet), and selenate (Se{sup VI}) were 2.1, 2.9, 4.3, and 3.5 ng mL{sup -1}, respectively. The proposed method was successfully applied to the speciation of selenium in water-soluble extracts of garlic shoots cultured with different selenium species. The results obtained suggested that UV-UV/TiO{sub 2} PCRD-ECVG should be an effective interface between HPLC and AFS for the speciation of elements amenable to vapor generation, and is superior to methods involving KBH{sub 4}. (orig.)

  7. The seasonal variation of water vapor and ozone in the upper mesosphere - Implications for vertical transport and ozone photochemistry

    Science.gov (United States)

    Bevilacqua, Richard M.; Summers, Michael E.; Strobel, Darrell F.; Olivero, John J.; Allen, Mark

    1990-01-01

    This paper reviews the data base supplied by ground-based microwave measurements of water vapor in the mesosphere obtained in three separate experiments over an eight-year period. These measurements indicate that the seasonal variation of water vapor in the mesosphere is dominated by an annual component with low values in winter and high values in summer, suggesting that the seasonal variation of water vapor in the mesosphere (below 80 km) is controlled by advective rather than diffusive processes. Both the seasonal variation and the absolute magnitude of the water vapor mixing ratios obtained in microwave measurements were corroborated by measurements obtained in the Spacelab GRILLE and ATMOS experiments, and were found to be consistent with several recent mesospheric dynamics studies.

  8. Ground-based eye-safe networkable micro-pulse differential absorption and high spectral resolution lidar for water vapor and aerosol profiling in the lower troposphere

    Science.gov (United States)

    Repasky, K. S.; Spuler, S.; Hayman, M. M.; Bunn, C. E.

    2017-12-01

    Atmospheric water vapor is a greenhouse gas that is known to be a significant driver of weather and climate. Several National Research Council (NRC) reports have highlighted the need for improved water vapor measurements that can capture its spatial and temporal variability as a means to improve weather predictions. Researchers at Montana State University (MSU) and the National Center for Atmospheric Research (NCAR) have developed an eye-safe diode laser based micro-pulse differential absorption lidar (MP-DIAL) for water vapor profiling in the lower troposphere. The MP-DIAL is capable of long term unattended operation and is capable of monitoring water vapor in the lower troposphere in most weather conditions. Two MP-DIAL instruments are currently operational and have been deployed at the Front Range Air Pollution and Photochemistry Experiment (FRAPPE), the Plains elevated Convection at Night (PECAN) experiment, the Perdigão experiment, and the Land Atmosphere Feedback Experiment (LAFE). For each of these field experiments, the MP-DIAL was run unattended and provided near-continuous water vapor profiles, including periods of bright daytime clouds, from 300 m above the ground level to 4 km (or the cloud base) with 150 m vertical resolution and 5 minute temporal resolution. Three additional MP-DIAL instruments are currently under construction and will result in a network of five eye-safe MP-DIAL instruments for ground based weather and climate research experiments. Taking advantage of the broad spectral coverage and modularity or the diode based architecture, a high spectral resolution lidar (HSRL) measurement capabilities was added to the second MP-DIAL instrument. The HSRL capabilities will be operational during the deployment at the LAFE field experiment. The instrument architecture will be presented along with examples of data collected during recent field experiments.

  9. Tracking atmospheric boundary layer dynamics with water vapor D-excess observations

    KAUST Repository

    Parkes, Stephen; McCabe, Matthew; Griffiths, Alan; Wang, Lixin

    2015-01-01

    Stable isotope water vapor observations present a history of hydrological processes that have impacted on an air mass. Consequently, there is scope to improve our knowledge of how different processes impact on humidity budgets by determining

  10. Single-footprint retrievals of temperature, water vapor and cloud properties from AIRS

    Science.gov (United States)

    Irion, Fredrick W.; Kahn, Brian H.; Schreier, Mathias M.; Fetzer, Eric J.; Fishbein, Evan; Fu, Dejian; Kalmus, Peter; Wilson, R. Chris; Wong, Sun; Yue, Qing

    2018-02-01

    Single-footprint Atmospheric Infrared Sounder spectra are used in an optimal estimation-based algorithm (AIRS-OE) for simultaneous retrieval of atmospheric temperature, water vapor, surface temperature, cloud-top temperature, effective cloud optical depth and effective cloud particle radius. In a departure from currently operational AIRS retrievals (AIRS V6), cloud scattering and absorption are in the radiative transfer forward model and AIRS single-footprint thermal infrared data are used directly rather than cloud-cleared spectra (which are calculated using nine adjacent AIRS infrared footprints). Coincident MODIS cloud data are used for cloud a priori data. Using single-footprint spectra improves the horizontal resolution of the AIRS retrieval from ˜ 45 to ˜ 13.5 km at nadir, but as microwave data are not used, the retrieval is not made at altitudes below thick clouds. An outline of the AIRS-OE retrieval procedure and information content analysis is presented. Initial comparisons of AIRS-OE to AIRS V6 results show increased horizontal detail in the water vapor and relative humidity fields in the free troposphere above the clouds. Initial comparisons of temperature, water vapor and relative humidity profiles with coincident radiosondes show good agreement. Future improvements to the retrieval algorithm, and to the forward model in particular, are discussed.

  11. The absorption spectrum of water vapor in the 2.2 μm transparency window: High sensitivity measurements and spectroscopic database

    International Nuclear Information System (INIS)

    Campargue, A.; Mikhailenko, S.N.; Vasilchenko, S.; Reynaud, C.; Béguier, S.; Čermák, P.; Mondelain, D.; Kassi, S.; Romanini, D.

    2017-01-01

    The weak absorption spectrum of water vapor in the important 2.2 μm transparency window is investigated with very high sensitivity. Overall, about 400 absorption lines were measured by Cavity Ring Down Spectroscopy (CRDS) and Optical-Feedback-Cavity Enhanced Laser Spectroscopy (OF-CEAS) in five spectral intervals: 4248.2–4257.3, 4298.4–4302.6, 4336.8.5-4367.5, 4422.4-4441.2 and 4514.6-4533.7 cm"−"1. The achieved sensitivity of the recordings (noise equivalent absorption, α_m_i_n, on the order of 2×10"−"1"0 cm"−"1) allowed detecting transitions with intensity values down to 1×10"−"2"8 cm/molecule, more than one order of magnitude better than previous studies by Fourier Transform spectroscopy. The rovibrational assignment was performed on the basis of variational calculations and of previously determined empirical energy values. Most of the newly assigned lines correspond to transitions of the ν_1, ν_3 and 3ν_2 bands of H_2"1"7O in natural isotopic abundance. Fourteen energy levels of H_2"1"7O, H_2"1"8O and HD"1"8O are newly determined. An accurate and complete spectroscopic database is constructed for natural water in the 4190–4550 cm"−"1 region (2.39–2.20 µm). The list includes about 4500 transitions with intensity greater than 1×10"−"2"9 cm/molecule, for the six most abundant isotopologues in natural isotopic abundance. Line positions were obtained by difference of empirical energy values determined from literature data and complemented with the present CRDS results. The list is made mostly complete by including weak transitions not yet detected, with positions calculated from empirical levels and variational intensities. The variational intensities computed by a collaboration between the University College London and the Institute of Applied Physics in Nizhny Novgorod are found to improve significantly previous results by Schwenke and Partridge. Examples of comparison of the constructed line list to CRDS spectra and to simulations

  12. Variations in stable hydrogen and oxygen isotopes in atmospheric water vapor in the marine boundary layer across a wide latitude range.

    Science.gov (United States)

    Liu, Jingfeng; Xiao, Cunde; Ding, Minghu; Ren, Jiawen

    2014-11-01

    The newly-developed cavity ring-down laser absorption spectroscopy analyzer with special calibration protocols has enabled the direct measurement of atmospheric vapor isotopes at high spatial and temporal resolution. This paper presents real-time hydrogen and oxygen stable isotope data for atmospheric water vapor above the sea surface, over a wide range of latitudes spanning from 38°N to 69°S. Our results showed relatively higher values of δ(18)O and δ(2)H in the subtropical regions than those in the tropical and high latitude regions, and also a notable decreasing trend in the Antarctic coastal region. By combining the hydrogen and oxygen isotope data with meteoric water line and backward trajectory model analysis, we explored the kinetic fractionation caused by subsiding air masses and related saturated vapor pressure in the subtropics, and the evaporation-driven kinetic fractionation in the Antarctic region. Simultaneous observations of meteorological and marine variables were used to interpret the isotopic composition characteristics and influential factors, indicating that d-excess is negatively correlated with humidity across a wide range of latitudes and weather conditions worldwide. Coincident with previous studies, d-excess is also positively correlated with sea surface temperature and air temperature (Tair), with greater sensitivity to Tair. Thus, atmospheric vapor isotopes measured with high accuracy and good spatial-temporal resolution could act as informative tracers for exploring the water cycle at different regional scales. Such monitoring efforts should be undertaken over a longer time period and in different regions of the world. Copyright © 2014. Published by Elsevier B.V.

  13. Water Vapor Diffusion and Adsorption of Sandstones: Influence of Rock Texture and Composition

    Directory of Open Access Journals (Sweden)

    Martin Keppert

    2016-01-01

    Full Text Available The term sandstone is used for wide range of rocks containing quartz clasts which can be cemented by secondary precipitated quartz or calcite; moreover the space between clasts can be filled by matrix. These facts result in existence of numerous rocks having highly various properties. Sandstones have been used as construction materials due to their good accessibility and workability. Since most of sandstones are porous, water vapor can penetrate through sandstone constructions. The rate of water vapor diffusion, as well as the vapor sorption isotherm, was determined for range of sandstone types. The diffusion resistance factor was found to be dependent on the total porosity of sandstone but the sorption behavior was strongly influenced by nature of the particular sandstone; the specific surface area of stone and presence of clay matrix are determining its sorption isotherm. The published data enable estimating (i diffusion resistance factor of a sandstone via knowledge of its total porosity and (ii the sorption isotherm via knowledge of the stone’s nature and specific surface area. This approach can significantly reduce the time necessary to acquire vapor-related properties of a sandstone.

  14. Bioventing - a new twist on soil vapor remediation of the vadose zone and shallow ground water

    International Nuclear Information System (INIS)

    Yancheski, T.B.; McFarland, M.A.

    1992-01-01

    Bioventing, which is a combination of soil vapor remediation and bioremediation techniques, may be an innovative, cost-effective, and efficient remedial technology for addressing petroleum contamination in the vadose zone and shallow ground water. The objective of bioventing is to mobilize petroleum compounds from the soil and ground water into soil vapor using soil vapor extraction and injection technology, and to promote the migration of the soil vapor upward to the turf root zone for degradation by active near-surface microbiological activity. Promoting and maintaining optimum microbiological activity in the turf root rhizosphere is a key component to the bioventing technique. Preliminary ongoing USEPA bioventing pilot studies (Kampbell, 1991) have indicated that this technique is a promising remediation technology, although feasibility studies are not yet complete. However, based on the preliminary data, it appears that proper bioventing design and implementation will result in substantial reductions of petroleum compounds in the capillary zone and shallow ground water, complete degradation of petroleum compounds in the turf root zone, and no surface emissions. A bioventing system was installed at a site in southern Delaware with multiple leaking underground storage tanks in early 1992 to remediate vadose zone and shallow ground-water contaminated by petroleum compounds. The system consists of a series of soil vapor extraction and soil vapor/atmospheric air injection points placed in various contamination areas and a central core remediation area (a large grassy plot). This system was chosen for this site because it was least costly to implement and operate as compared to other remedial alternatives (soil vapor extraction with carbon or catalytic oxidation of off-gas treatment, insitu bioremediation, etc.), and results in the generation of no additional wastes

  15. Observed Responses of Mesospheric Water Vapor to Solar Cycle and Dynamical Forcings

    Science.gov (United States)

    Remsberg, Ellis; Damadeo, Robert; Natarajan, Murali; Bhatt, Praful

    2018-04-01

    This study focuses on responses of mesospheric water vapor (H2O) to the solar cycle flux at Lyman-α wavelength and to dynamical forcings according to the multivariate El-Nino/Southern Oscillation (ENSO) index. The zonal-averaged responses are for latitudes from 60°S to 60°N and pressure-altitudes from 0.01 to 1.0 hPa, as obtained from multiple linear regression analyses of time series of H2O from the Halogen Occultation Experiment for July 1992 to November 2005. The results compare very well with those from a separate simultaneous temporal and spatial (STS) method that also confirms that there are no significant sampling biases affecting both sets of results. Distributions of the seasonal amplitudes for temperature and H2O are in accord with the seasonal net circulation. In general, the responses of H2O to ENSO are anticorrelated with those of temperature. H2O responses to multivariate ENSO index are negative in the upper mesosphere and largest in the Northern Hemisphere; responses in the lower mesosphere are more symmetric with latitude. H2O responses to the Lyman-α flux (Lya) vary from strong negative values in the uppermost mesosphere to very weak, positive values in the tropical lowermost mesosphere. However, the effects of those H2O responses to the solar activity extend to the rest of the mesosphere via dynamical processes. Profiles of the responses to ENSO and Lya also agree reasonably with published results for H2O at the low latitudes from the Microwave Limb Sounder.

  16. Stoichiometric control for heteroepitaxial growth of smooth ɛ-Ga2O3 thin films on c-plane AlN templates by mist chemical vapor deposition

    Science.gov (United States)

    Tahara, Daisuke; Nishinaka, Hiroyuki; Morimoto, Shota; Yoshimoto, Masahiro

    2017-07-01

    Epitaxial ɛ-Ga2O3 thin films with smooth surfaces were successfully grown on c-plane AlN templates by mist chemical vapor deposition. Using X-ray diffraction 2θ-ω and φ scans, the out-of-plane and in-plane epitaxial relationship was determined to be (0001) ɛ-Ga2O3 [10\\bar{1}0] ∥ (0001)AlN[10\\bar{1}0]. The gallium/oxygen ratio was controlled by varying the gallium precursor concentration in the solution. While scanning electron microscopy showed the presence of large grains on the surfaces of the films formed for low concentrations of oxygen species, no large grains were observed under stoichiometric conditions. Cathodoluminescence measurements showed a deep-level emission ranging from 1.55-3.7 eV; however, no band-edge emission was observed.

  17. Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO3 Photocatalysts.

    Science.gov (United States)

    Han, Kai; Lin, Yen-Chun; Yang, Chia-Min; Jong, Ronald; Mul, Guido; Mei, Bastian

    2017-11-23

    SrTiO 3 is a well-known photocatalyst inducing overall water splitting when exposed to UV irradiation of wavelengths water-splitting efficiency of the Mg:SrTiO x composites is up to 20 times higher compared to SrTiO 3 containing similar catalytic nanoparticles, and an apparent quantum yield (AQY) of 10 % can be obtained in the wavelength range of 300-400 nm. Detailed characterization of the Mg:SrTiO x composites revealed that Mg is likely substituting the tetravalent Ti ion, leading to a favorable surface-space-charge layer. This originates from tuning of the donor density in the cubic SrTiO 3 structure by Mg incorporation and enables high oxygen-evolution rates. Nevertheless, interfacing with an appropriate hydrogen evolution catalyst is mandatory and non-trivial to obtain high-performance in water splitting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Water vapor increase in the lower stratosphere of the Northern Hemisphere due to the Asian monsoon anticyclone observed during the TACTS/ESMVal campaigns

    Science.gov (United States)

    Rolf, Christian; Vogel, Bärbel; Hoor, Peter; Afchine, Armin; Günther, Gebhard; Krämer, Martina; Müller, Rolf; Müller, Stefan; Spelten, Nicole; Riese, Martin

    2018-03-01

    The impact of air masses originating in Asia and influenced by the Asian monsoon anticyclone on the Northern Hemisphere stratosphere is investigated based on in situ measurements. A statistically significant increase in water vapor (H2O) of about 0.5 ppmv (11 %) and methane (CH4) of up to 20 ppbv (1.2 %) in the extratropical stratosphere above a potential temperature of 380 K was detected between August and September 2012 during the HALO aircraft missions Transport and Composition in the UT/LMS (TACTS) and Earth System Model Validation (ESMVal). We investigate the origin of the increased water vapor and methane using the three-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS). We assign the source of the moist air masses in the Asian region (northern and southern India, eastern China, southeast Asia, and the tropical Pacific) based on tracers of air mass origin used in CLaMS. The water vapor increase is correlated with an increase of the simulated Asian monsoon air mass contribution from about 10 % in August to about 20 % in September, which corresponds to a doubling of the influence from the Asian monsoon region. Additionally, back trajectories starting at the aircraft flight paths are used to differentiate transport from the Asian monsoon anticyclone and other source regions by calculating the Lagrangian cold point (LCP). The geographic location of the LCPs, which indicates the region where the set point of water vapor mixing ratio along these trajectories occurs, can be predominantly attributed to the Asian monsoon region.

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

    Directory of Open Access Journals (Sweden)

    J. Meyer

    2015-07-01

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

  20. Using Satellites to Investigate the Sensitivity of Longwave Downward Radiation to Water Vapor at High Elevations

    Science.gov (United States)

    Naud, Catherine M.; Miller, James R.; Landry, Chris

    2012-01-01

    Many studies suggest that high-elevation regions may be among the most sensitive to future climate change. However, in situ observations in these often remote locations are too sparse to determine the feedbacks responsible for enhanced warming rates. One of these feedbacks is associated with the sensitivity of longwave downward radiation (LDR) to changes in water vapor, with the sensitivity being particularly large in many high-elevation regions where the average water vapor is often low. We show that satellite retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Clouds and the Earth's Radiant Energy System (CERES) can be used to expand the current ground-based observational database and that the monthly averaged clear-sky satellite estimates of humidity and LDR are in good agreement with the well-instrumented Center for Snow and Avalanche Studies ground-based site in the southwestern Colorado Rocky Mountains. The relationship between MODIS-retrieved precipitable water vapor and surface specific humidity across the contiguous United States was found to be similar to that previously found for the Alps. More important, we show that satellites capture the nonlinear relationship between LDR and water vapor and confirm that LDR is especially sensitive to changes in water vapor at high elevations in several midlatitude mountain ranges. Because the global population depends on adequate fresh water, much of which has its source in high mountains, it is critically important to understand how climate will change there. We demonstrate that satellites can be used to investigate these feedbacks in high-elevation regions where the coverage of surface-based observations is insufficient to do so.